FlowLabPro, automatic low flow meter calibration stand

The Litre Meter temperature-controlled volumetric low-flow calibration rig FlowLabPro delivers automatic calibration of flow meters and instrumentation within a flow range of 0.0006 to 200 l/hr to an accuracy of ±0.2 per cent and a repeatability of ±0.05 per cent. Brochure.

Accuracy is much greater and uncertainty is much lower than was previously achievable using volumetric calibration.

All the associated tanks, pumps, ultrasonic sensors, pressure gauges and temperature probes are housed in a compact and manoeuvrable temperature-controlled cabinet.

FlowLabPro for low flow determination on a range of fluids

Now commercially available from Litre Meter, the new volumetric low-flow calibration rig can measure any fluid type within reason and features a reverse flow testing facility.

Charles Wemyss, CEO of Litre Meter, said: “We recently introduced our LF03 low-flow VFF rotary piston meter taking the capability of our VFF flow meter range down to lower flows than ever before – for example, on a fluid with a viscosity of 10 cSt the LF03 will measure down to 0.06 litres/hour at pressures of 1 bar right up to 4,000 bar.

“As a result of this innovation the next logical step was to develop a calibration rig capable of accurately measuring ultra-low flow rates. We were so happy with the results that the decision was made to make the volumetric low flow calibration rig available on the open market.”

    • Calibrate up to 5 flow meters with one setup
    • Automatic selection of up to 6 pre-loaded fluids from 0.2 cSt to 1000 cSt
    • Flow rate calibration 0.01 ml/min to 200 l/hr on all viscosity fluids
    • Temperature controlled 16°C to 24°C
    • Visual and Audio warning on completion
    • Automatically generates Calibration Certificates
    • Easy calibration setup and user interface
    • Repeatability ±0.05%
    • Accuracy ±0.2%
    • Small footprint – 120x60cm
    • Can be left overnight
    • Automated calibration over a number of flow rates from minimum to maximum
    • Significantly reduced calibration times

FlowLabPro automatic flowmeter calibration at low flows

What Flowmeter calibration techniques do Litre Meter use?

Essentially, there are three separate calibration methods that Litre Meter have in-house to calibrate a range of flowmeters.  As the fluids can vary from water to thick oil and the flows range from a few millilitres per hour to 1,000 litres per minute, there are not only three calibration methods but 10 rigs in total, all traceable to National Standards.

The most common calibration method for Litre Meter is gravimetric with flying start and stop.  This method, as the names suggests, records the weight to provide a mass flow. Frequently, this is converted to a volume flow after determination of density.  After that, the use of master meters is popular for higher flows, above a few litres per minute. Finally, where the flow rates are outrageously low – i.e. just millilitres per hour – Litre Meter has a volumetric pistonless design – the FlowLabPro.

Gravimetric Flying Start-Stop

Most Litre Meter flowmeters are calibrated using a gravimetric method.  A flow rate is established through the flowmeter with the output flow returning to the main reservoir.  At the commencement of test, the output flow is diverted into a weigh tank.  When sufficient volume of fluid has been collected in respect of that particular flow rate, the output flow is diverted to the main reservoir once more.  The time for the volume of fluid to be collected is recorded, together with the number of pulses produced by the transmitter.

The density of the fluid is determined at time of calibration.  Volume divided by time equals flow rate.  The number of pulses divided by volume equals the pulses per litre Meter Factor.  The calibration certificate is prepared from a table of these values.  If on-site calibration is required and a known volume of fluid flow can be established, then the same calculations apply to reproduce the calibration certificate.

Significant effort should be spent ensuring that the start and stop timing accurately reflect when flow is being weighed and that the speed of changeover is maximised. With modern, accurate weigh scales and timing the stop/start transitions are where precision improvements are made. Litre Meter have developed a simple program that enables quick monitoring of diverter performance and aids the operator in adjusting the timing.

When pulse rates are very low, such as in the VFF and some other positive displacement flowmeters, the flow rig electronics are altered such that a calibration run commences on a pulse and finish on a pulse. For example, a calibration run is dialled in requiring 60 pulses.  The operator starts the test with continuous flow running through the MUT. When the next pulse is sensed the diverter operates and the scales begin weighing the fluid. After 60 pulses pass the diverter switches back and measurements are taken. There will be 60 pulses, a specific weight and a specific time enabling the calculation of flow rate and pulses per mass unit. With an sg reading from a suitably accurate densitometer then the rate can be calculated in volumetric terms and the pulses used to calculate pulses per litre.  There is no uncertainty in the number of pulses i.e. whether the next pulse was about to arrive or had just been. This is usually an uncertainty of up to two pulses.  There is an unknown time at Start of diversion but this is somewhat equalled out at the Stop side. Good calibration of the start/stop sequence can almost eliminate this unknown.

Master Meter

As the flow rate increases the compactness of the Gravimetric method with its diverter starts to die away and the rigs become very large. At Litre Meter we have a good crossover between the upper end of the gravimetric to the lower end of the master meter which provides some flexibility and confidence.  For water the gravimetric rigs are suitable for flows up to 30 l/min and the master meters commence at 1 l/min. For oils it’s 10 and 0.1 respectively. Without the knife-edge start of the gravimetric flying start (above) the master meter technique pivots (sorry for the pun) around dual chronometry.

The Meter Under Test produces a pulse train simultaneously with the Master Meter but at a different frequency.  The computer program starts and stops the test period depending on the preset length of test and the number of pulses desired.  The preset length is then subtly adjusted so that a precise number of pulses is used. Further analysis of the MUT pulse rate counts the number of pulses, and more importantly, determines the fractional number of pulses at the start and end of test.  Finally, the test is repeated at least three times at each flow rate.  These are installed in a continuously running system, in a loop, thus enabling multiple tests in quick succession.  The pump or valve position is then altered to process all of the desired flow rate range in a suitable number of steps.

Piston-less piston prover

For investigation of very low flows our traditional gravimetric rigs were unable to control and/or develop low flows consistently. For the LF03 the low flows are actually lower than the leak flows through the valves or our then smallest system. A change of method was required.  Starting with a series of pumps a method was instigated using a rising column of fluid being monitored by an accurate height sensor.  With a variety of column diameters a wide range of flow rates can be generated and measured accurately.  Pulse interpolation is used in much the same way as for dual chronometry, above, except that the MUT and the height sensor are the two sources of pulses. All of the components including a choice of fluid reservoirs are together in one enclosure, temperature controlled, to maintain consistency.  Up to 4 rotors and chambers can be calibrated together over the required flow rate range enabling calibration to continue overnight, unsupervised.  Additional software programs can quickly determine minimum achievable flow which significantly speeds up parts selection for our LF and ULF calibration levels.



The TASI Group Continues Expansion with 2nd Acquisition in Q2

Marlborough, MA – May 9, 2019 – The TASI Group continues the growth of its Flow Segment business with the recent acquisition of Sierra Instruments, a global company specializing in the manufacture of flow measurement instrumentation.   This is the 2nd acquisition finalized by The TASI Group in just two months.

Offering flow and test solutions to international markets, Sierra Instruments is comprised of two divisions: FLOW, headquartered in Monterey, California and AUTO, headquartered in Malvern, United Kingdom.  The FLOW Division manufactures mass flow meters and flow controllers for gas, liquid, or steam application.  The AUTO Division builds complex, custom, integrated test facilities and world-class engine and vehicle test automation systems.

“Sierra’s flow product portfolio compliments TASI Flow businesses, offering new technologies including Transit-time ultrasonic and vortex shedding, among others,” explained TASI CEO John McKenna. “This acquisition is strategically important to the continuing growth of TASI Flow and the TASI Group.”

With this recent acquisition. the TASI Flow Segment now includes the following operations:

  • Air Monitor
  • AW-Lake Company
  • EXACT Dispensing Systems
  • Fox Thermal
  • Greyline
  • KEM Kuppers Electromechanik GmbH
  • Litre Meter
  • Onicon
  • Pulsar Process Measurement
  • Seametrics
  • Sierra Instruments
  • SignalFire Wireless Telemetry
  • Vögtlin Instruments GmbH
Logos of the 13 TASI Flow companies
Logos of the 13 TASI Flow companies

For more information about Sierra Instruments, visit https://www.sierrainstruments.com/.

About the TASI Group

The TASI Group of Companies is comprised of three technologically advanced product platforms commonly linked by a disciplined focus on Test, Measurement, and Assembly. Each TASI company delivers products and services to today’s world manufacturing environments, focusing on Automotive, Medical Devices, Oil and Gas, Plastic Containers, Consumer and General Industrial markets. For more information about the TASI Group, visit their Web site at www.tasigroup.com

Litre Meter and KEM flowmeters


Litre Meter manufacture and distribute an enviable range of flowmeter. From the low flow robustness of the VFF positive displacement meter to the precision of the Tricor Coriolis range, Litre Meter have a solution to your tricky measurement application.  Call our engineers now to receive the best advice on meter selection and application.

LM & MM Pelton Wheel

LMX, pictured, was designed from the outset with some simple parameters.  A pressure rating of 100bar coupled with a temperature rating of 100°C. End couplings are wither ½”NPT or BSP with built-in straight lengths of pipe. As a bonus the minimum fluid temperature can be -50°C and there are just 3 wetted materials. With 316 stainless steel, PTFE and sapphire in contact with the fluid there are few applications that it can’t handle. Flow rate abilities are selected by different internal jets enabling the same size body to measure from 0.004 l/min up to 65 l/min in just a few sizes.


VFF Positive Displacement

The group of VFF meters pictured are all in the LF range which covers the LF03, LF05 and LF15.  The internal chambers are interchangeable, if required, and future developments of this design will all be based around the same size chamber.  The FlowPod instrument is our standard fit offering most customers exactly what they want. Pressure and temperature ratings range from 414bar to 1380bar and beyond with temperatures to over 100°C depending on area type.

ZHM Gear Meter

The KEM ZHM, shown in High Pressure spec with blue Xylan coated bolts, is a traditional round gear positive displacement meter ideal for hydraulics measurement being capable of wide flow turndowns and a range of materials and specifications.

Tricor Coriolis

The 3rd generation Tricor Coriolis meter is now available with DSP Digital Signal Processing electronics for the ultimate in precision, accuracy.  The standard electronics is still available for general industry use at ±0.3% of reading levels. Sizes cover the majority of applications and the plain bores make selection simple.  Where pressures head north of 300 bar the TCMH can be specified which also has unique OIML137 certification for liquid hydrogen dispensing, also MID-002.

SRZ Helical Screw and HM Turbine

The KEM SRZ Helical Screw Positive Displacement flowmeter and the KEM HM axial turbine flowmeter complete the Litre Meter and KEM range. The SRZ are especially good for high viscosity or abrasive or filled liquids where they are the natural preference to the ZHM.  Viscosity change has little effect and the largest can measure 400 l/min.

The HM turbines are the workhorse of industrial measurement with a clear line of design going back several decades. They are well suited to measuring low and medium viscosity liquids whether they are lubricating or not. They can be specified for cryogenic fluids too. A variety of end fittings and materials reflect their design flexibility.


TASI Adds ONICON to Flow Segment Group

TASI and Onicon

The TASI Group recently acquired ONICON Incorporated, a private company specializing in the design and manufacture of flow meters and energy measurement systems. ONICON addresses liquid flow, steam flow, natural gas flow, airflow, and thermal energy applications with a broad range of flow meter technologies, including electromagnetic, turbine, ultrasonic, thermal mass, vortex, Pitot tube and BTU meters. Through its own acquisitions, ONICON offers six brands including:

  • Onicon
  • Air Monitor
  • Seametrics
  • Fox Thermal
  • Greyline
  • Pulsar

Larger Segment

The ONICON acquisition is another is step in the continuing development of TASI’s premier flow and level measurement business. The combined businesses now form a substantially larger TASI Flow Segment that offers an extensive range of technology to better serve customers around the globe and extend into new markets.
”The ONICON acquisition is a strategic win for everyone,” stated TASI CEO John McKenna. ”ONICON’s diversified portfolio of flow technologies compliment TASI Flow businesses with little overlap in technology, industries and geographic regions. This acquisition positions both businesses on an aggressive growth path “

Existing TASI Flow Group:

The organization joins the TASI Flow Segment of complementary businesses which includes:

  • AW-Lake Company
  • KEM Kuppers Electromechanik GmbH
  • Litre Meter
  • SignalFire Wireless Telemetry
  • Vogtlin Instruments GmbH
  • EXACT Dispensing Systems

What happens now?

John Norris, former ONICON President and Chief Executive Officer, will serve as TASI Flow Segment President with responsibilities for overseeing the entire combined group of world-class flow businesses. He will report directly to John McKenna the TASI Group CEO.

KEM Küppers flowmeters include the ZHM round gear PD meter

Litre Meter are the exclusive UK distributors for KEM Küppers.  These include the ZHM, SRZ positive displacement, HM turbine and the Tricor coriolis series. Sign up for FlowSight, the Litre Meter newsletter.

KEM ZHM01/3 gear meter
KEM ZHM01/3 gear meter

The ZHM series is highly engineered round gear PD flowmeter suitable for a slew of different applications such as hydraulic oil, automotive paint and chemical dispense measurement.

  • From 0.002 to 1 LPM to 1,000 LPM
  • Ratings to 315, 414, 690 bar and higher
  • Accuracy: ±0.5% of reading or better
  • Repeatability: ±0.05% of reading
  • Can be installed in any orientation
  • Cartridge, compact & aluminium options.

All of these units are manufactured in Germany by Litre Meter’s sister company, KEM Kueppers GmbH.



Litre Meter – who are we?

1. Can we start with some background on yourself and a brief history of Litre Meter?

Litre Meter was founded in 1975 by Sandy Wemyss. It originally designed and manufactured a Pelton wheel turbine flowmeter – still on sale today – along with a comprehensive selection of flow instrumentation. After Sandy’s death in 1978 his son, Charles Wemyss joined in 1982 and has been there ever since.

2. What inspired you to establish Litre Meter?

It was spun out of a development company looking at many types of flowmeter technologies for a variety of clients. One particular design was not used by that customer and was the genesis of the LM Pelton Wheel line. The MM soon followed and so a wide range of applications could be solved and Litre Meter Limited was established.

3. Given the massive proliferation of marketing technology, how do you see the Litre Meter market evolving over the next few years?

Litre Meter will always find a market for flowmeters at the margins. We are famous for providing flow solutions that are out of the ordinary, perhaps at low flow, with special materials, high pressures, or with specific pressure drop requirements. Whilst everyone one of our meters can measure the ordinary we will always aim for the niches.

4. Could you tell us about a standout business campaign to supply flow meters?

Our best campaigns come through word-of-mouth. Our two largest orders were as a direct result of providing, successfully, similar systems to original clients. They were impressed and those teams, when the time came, placed orders for similar equipment.

5. One word that best describes how you work.


6. Something you do better than others – the secret of your success? 

We still feel like a small family company. Staff turnover is very low, our longest employee has been here 31 years.

7. You did a thesis on ‘Weight reduction in the car with particular reference to the Wankel rotary engine’ in your Mechanical Engineering (The University of Sheffield). Can you brief the major points on it?

Even back in 1981, we were looking forward. Fuel consumption and efficiency were still drivers in car design but not as much as they are today. The thesis explored weight reduction in all aspects of the car but especially in the engine. There are great challenges to non-metallic materials in the engine bay relating to temperature and pressure. Various materials were explored, and simple components identified for evolving into composite construction. The Wankel engine has since fallen by the wayside, limited in its combustion efficiency with its awkwardly shaped combustion chamber. However, it now finds a role in UAVs where it’s relatively light weight and low vibration characteristics are close to ideal.

8. Litre Meter had received a Queen’s Award for Enterprise, which is an outstanding achievement to be recognized at the highest levels for your success. Can you please elucidate on this?

Litre Meter awarded Queen’s Award for International Trade

Specifically, this was an award for Export, reflecting our global success. Traditionally Litre Meter finds its markets overseas, not only in the USA but also in South East Asia and Europe. For a period of several years, our export orders increased culminating in over 70% in 2015.

9. Can you please address the challenges of low-flow measurement?

The term ‘low flow’ has different values to different people. The VFF can easily measure down to 200 milliliters per hour. For other meters, this will be considered impossibly low. For some, 200 ml per day is achievable but not necessarily with the right combination of other specifics such as viscosity or pressure. For Litre Meter, the challenge is to achieve these low flows in a package suitable for some of the most arduous conditions on the planet. We select appropriate materials, backed up by ISO9001:2015 quality management, with high specification testing procedures, high-pressure ratings and high resistance coatings for longevity.

10. How do Litre Meter’s flow meters meet the demands of your customers and transform their business in the new digital economy?

Litre Meter’s Mission Statement is very simple: Our purpose is to provide flow measurement solutions to enable our customers to control their usage of fluids, materials ultimately to reduce costs and environmental impact. The digital economy has the same focus as most economies: to drive down costs and reduce the ecological footprint. High-performance measurement.

11. What are some of the primary end user drivers and requirements in the market that impact the flow meter productivity, and which are the primary market sectors represented by your major customers?

Flowmeter performance is king in our main market which is Oil & Gas. Clients drove the design of the VFF meter to what it is today. The components have been optimized to be as compact and lightweight as possible whilst retaining the flow performance and instrumentation specification. The adoption of our CIFM philosophy has produced a number of crucial advances in meter and instrument design. CIFM is an abbreviation of Chemical Injection Flow Meter. The first and most obvious is that the meters are more compact. Underneath the skin though there are important advancements in components, reliability, Exd philosophy and instrumentation. Standardisation has been a keyword and Litre Meter expect 80% of future orders to be from a standard (but wide) range rather than 20% with 80% bespoke. Over 800,000 variations are possible and every drawing including GA and lifting is available at the time of inquiry.

12. We understand that Litre Meter will enlarge market sales to drive further expansion. Can you share with us in which geographic and technology areas this will cover and do you anticipate further growth via acquisition?

Litre Meter has a 5-year plan and this involves organic growth within our current markets plus expansion into other markets and acquisition. Our geography is driven by our customers and therefore currently covers many of the oil and gas hotspots and includes multiple areas worldwide where skids are built. Our technology platform is stable but we continuously push the operating boundaries to measure lower flows with or without higher pressures.

About: Charles Wemyss – CEO
Charles Wemyss

Charles Wemyss is the CEO of Litre Meter Limited, the flowmeter experts in supplying Mass, Water, and Chemical Injection Flowmeters worldwide. He holds the Bachelor of Engineering (BEng) degree from The University of Sheffield. His area of expertise lies in Oil & gas flow measurement and especially chemical injection measurement for positive displacement meters and Coriolis mass meters, over the last twenty- five years. Charles Wemyss plays a key role in launching a bespoke range of customisable flowmeters, growing the organization’s reach worldwide.


Originally published in PlantAutomation.


A history of subsea flowmetering – Litre Meter experts

Here is a short history of deploying flowmeters, of various technologies, subsea
France, 1985:
The first custom design involved the LM pelton wheel. A compact product was required for installation on a submarine.  The pelton wheel is a radial turbine meter type suitable for low viscosity liquids and, in this incarnation, with a stainless steel body rated to 20 bar internal pressure and capable of 0.1 to 28 l/min. Sign up for FlowSight, the Litre Meter newsletter.
Challenger Oceanic, 1992:
Litre Meter contributed a plastic bodied LM pelton wheel.  The internal and external pressures were identical so the plastic housing was quite strong enough with simple hose connections. The electronics, however, was inside a submersible pod where the pressure was 1 bar. To withstand the pressure differential (300bar, 3000m) the sensor wall, thin for good signal acceptance, was constructed in a titanium alloy, previously purposed for the nose cone of a Harrier Jump Jet. The meter was installed on Alvin and used as part of a sampling system in subsea fumaroles, in places such as the Marianas Trench. Particles were collected and the volume of water measurement helped determine the percentage of solids.
North Sea, 1993:
For a simple solution to the flotation and righting of an offshore vessel two VFF 4 flowmeters were designed with subsea totaliser displays.  The VFF4 was the original VFF flowmeter size capable of measurement, at that time, of 4 l/minute as they were fitted with carbon graphite rotors.  A simple reed switch sensor was used.  With a battery powered LCD display mounted behind a clear acrylic window the diver were able to assess the amount of hydraulic fluid being used and thereby the angle of the platform as it slowly rotated from it’s horizontal transport position.  The challenge was to design a compact subsea display against a tight cost restraint.
Heron and Egret, 1996:
As Litre Meter extended it’s capability with increased design freedom internal pressures increased to 690 bar. The application required a very low flow of chemical to be measured and the smallest meter at the time, the MF15, was selected, again with a carbon graphite rotor.  The next problem was designing for 300 bar external pressure and provide a loop powered 4-20mA output with a customer specified Tronic connector.  Two sensors were utilised with a well designed electronic board that provided redundancy by continuous monitoring each sensor.  Typically, scale inhibitor was measured at 0.5 to 2.5 litres per hour. A stainless steel housing was constructed incorporating the connector and fully O-ring sealed.  The housing was tested by Sira at 300bar.
VFF MF15 for subsea duty with 4-20mA loop powered output
Subsea visual rate display, 2005 onwards
By upgrading an existing turbine design Litre Meter engineers were able to add a submersible battery powered display for use by an ROV mounted camera.  Starting with a standard ‘topsides’ meter a subsea collar was welded on. Then a stainless steel canister was constructed with a heavy duty acrylic window to withstand the pressure at 800m external depth. A large height LCD rate and total instrument was incorporated.  As the turbine used a magnetic sensor requiring no power, a simple battery powered solution was provided to the client. Flow rates were typically 5 to 90 l/min of water but the design has been incorporated in to different size turbines since.
Turbine flow meter for subsea duty with battery powered LCD totaliser
Galley Tieback, 2006:
Hydraulics measurement was needed, in a very specific envelope. The fluid was Castrol Brayco running at a wide ranging 1 to 50 litres per hour. Internal pressure was up to 414bar and the external pressure was 20bar.  A 4-20mA loop powered electronics was integrated within a cylindrical housing and utilised a Tronic connector.
MF30 VFF flowmeter developed for subsea use, mounted
Thunderhorse, 2006
When hydraulic fluid is measured valve position can be interpreted.  When subsea this is considerably more difficult as the measurement has to be compact and resist high pressures inside and out.  With an innovative manifold base little of the VFF MF30 meter remained. The sensor was standard but all other aspects of the design were optimised to use least space, maintain a pressure rating in and out and incorporate a custom electronics interface. Forward and return lines were monitored with pressures at 760bar and 345bar respectively. External pressures could be up to 300bar. Glass to metal seals for the sensor outputs were utilised together with the redundant sensor design used before.
MF30 VFF flowmeter developed for subsea use, with manifold mounting
Subsea valve, 2006 onwards:
The VFF meter in it’s various sizes were becoming more and more popular for chemical injection particularly at high pressures and low flows.  The MF15 was redesigned as the LF15. This enabled a higher accuracy, lower flow ability and crucially a smaller chamber diameter.  This, in turn, allowed a more compact meter design at the same pressure or, usefully, a higher pressure rating for a specific cap diameter.  The design brief was simple: Could we design a 1,035 bar meter for 90 litres per hour and 345 bar external rating in the same envelope as a can of Guinness? – we’re still working on this! What we did end up with is a fairly compact device (100mm diameter and 125mm long) where we  supply just the chamber and cap and the customer integrates these parts into a subsea module.  The unique chamber design allows pressure independent measurement whether at 1 bar or 1,000 bar.
With an expected lifetime of 30 years all efforts were made to increase the ability of the rotor and chamber.  Extensive testing on various bearings and coatings refined the design, retaining it’s simplicity but greatly improving resistance to high flow shocks and significantly improving low flow performance.  A full 2.5 years continuous running at twice the previous maximum flow demonstrated it’s durability. Careful calibration showed that low flow measurement at the start and the end of the 30 months were identical thereby proving that 90 litres per hour was the new maximum with that design and coating.
Hundreds are in service subsea around the world. The meter is used to provide feedback on the flow rate of chemical.  The pulse output (with a redundant sensor) requires no power and the meter has excellent particle size acceptance.
North Sea, 2012
The VFF4, when specified with a PVD coated Nitronic rotor and chamber, can measure up to 8 litres per minute. With a pressure rating of 300 bar (external and internal) a compact 3 wire 4-20mA meter was designed with 1/2″NPT connections. Hydraulics footprinting was then possible subsea. A Seacon Micro Wet-Con 4 pin connector was utilised with dual reed switches for redundancy. Field not known.
VFF4 VFF flowmeter developed for high pressure subsea use on hydraulics
North Sea, 2013
Apart from the Pelton Wheel, turbine and VFF rotary piston flowmeter designs there are other meter types that an provide a significant design benefit to subsea modification.  The ZHM gear meter offers a wide range and high pulse output rate. A SubConn subsea connector was incorporated and a high pressure 690bar design modified for 0.3 to 6 litres per minute.  The application was again chemical injection and 409 bar was the external rating.
ZHM positive displacement gear meter for subsea use
North Sea, 2015 onwards
When a clean sheet of paper is used then a streamlined solution can result.  The subsea turbine flow meter developed for hydraulics measurement from 3 to 33 l/min (HM009) is typical of this approach.  The turbine blades are standard whilst the sensor and Canbus electronics board are encapsulated by welding into the integral stainless steel housing. The customer specified subsea connector provides easy integration electronically. Internally, the meter can withstand 1,035 bar (tested to 1550 bar, 22,500 psi) and externally the specification allows for 300 bar.
HM turbine flowmeter for subsea use in two common configurations

The drive to save weight from the flowmeter experts

There was a very interesting article about Shell in last months Fortune. It explains how Shell were approaching the next decade and building 4 different scenarios of oil price and availability and their investment reactions to those.  I’ve included the link at the end of this article.  Sign up for FlowSight, the Litre Meter newsletter.

It also detailed the effect on their platform design when the oil price suddenly reduced.  The most striking image is of two platforms designed in different eras.  Appomattox will soon be active in the Gulf of Mexico so would have been designed in 2013 with a Final Investment Decision (FID) in July 2015.  Vito was designed in early 2014, when oil was at $100.  By 2015, when the price had slipped, Vito was looking bulky. In early 2016 it was decided to slim it down to be profitable at $40.

A radical design overhaul slashed the top weight over the next year, from 40,000 tons to 8,900 tons. The shell team right-sized Vito, for a world of ‘peaking oil demand’.

The similarities with Litre Meter developing the FlowPod instrument seem tenuous – and we don’t have meters on either platform, which is unusual. But, the FlowPod was developed over 12 months from the original FPod Exd flow display.  The prime motive was size reduction and improved performance.  With that, and unclear at the start of the process, was a beneficial reduction in meter size and weight into the bargain.

The original purpose of the redesign was two-fold: firstly, to reduce the size of the instrument enclosure – mounting them remotely from the meter produced some unexpected challenges for our clients from time-to-time; secondly, to replace on obsolescent internal electronic component. It transpired that the new component was even bigger than the old one so a thorough instrumentation re-design was discussed, eliminating the large isolator and taking the benefit of a reduced enclosure size. This wasn’t an easy task and soon we were down the road of a ground-up redesign encompassing the traditional sensor which now had to be part of an Exd system.

With a new sensor every cap was also redesigned and there was a knock-on effect to the VFF body. We coupled this refinement with a desire to provide our customers with more standard meters ‘off-the-shelf’ shifting our traditional 80% bespoke/20% standard to 80/20 standard design vs custom, offering better availability.
When the dust had settled the new VFF, although having the same flow rate ranges, had a standardised Pressure Balanced Chamber design with a redesigned sensor, a compact display dubbed FlowPod certified Exd and over 114,000 different standard designs.
Litre Meter have analysed our customer’s requirements which has resulted in the various meter sizes being available in most appropriate connection sizes and styles. For example:

VFF flowmeter sizes and selected threaded connections

The sheer range of choice, which also encompasses body & cap materials, seal materials and instrumentation has effectively designed out the need for customization. Drawings are available for over 114,000 different VFF configurations – including

  • General Arrangement,
  • Parts List and
  • Lifting Diagrams, together with a
  • STEP file, allowing instant modelling.

Lead times are reduced, enabling customers to bring their projects to fruition earlier. There is a dedicated program that enables Litre Meter and their distributors to select and configure flowmeter solutions quicker and more accurately.

All the VFF range are designed around the Pressure Balance Chamber.  Cap and body sizes have been rationalised and minimum pressure ratings increased. For example, the most popular 1/2″NPT female body is now rated to 530 bar rather than 414 bar previously, increasing it’s usability just by varying bolting material.

Here are two identically ranged meters with 1/2″NPT female connections:

The older FPod on the left dwarfs the more compact FlowPod and rationalised body and cap.

Instrument weight plummets from 5 kg to 1.2 kg and display enclosure diameter reduces from 6.5 to 3.5 inches.  Stainless steel is now standard.   Here’s a quick comparison:

FlowPod benefits

We think this clearly demonstrates Litre Meter’s commitment to continuous improvement, matching Shell’s dramatic reductions on the Vito project. Fortune article.

 Sign up for FlowSight, the Litre Meter newsletter.

Upgrading your FPod to FlowPod – a simple guide

Litre Meter ships biggest ever VFF flowmeter!

At the end of 2017 there was more activity than usual at Litre Meter as some of the largest VFF meters were gathered together for assembly and calibration. A complex project involving 7 different VFF sizes including the largest ever VFF was nearing completion.  The V400 weighs a hefty 600kg and measures a suitably massive flow rate of 330 l/min and is designed for 19m³/h normal flow. The liquid is lean MEG (monoethylene glycol) which is used as an antifreeze in offshore production platforms, amongst others.  The VFF series normally tops out at 2″ connections so 6″ was quite an engineering and logistical task.  Sign up for FlowSight, the Litre Meter newsletter.

The pressure rating of 260+bar and the customer’s 6″ line dictated the use of 6″ANSI2500 connections and a 316L body.  On top of this is the standard chemical injection instrument, the FlowPod, which provides a clear display, 2 wire operation and HART all in a 316 Exd enclosure.

6" VFF V400 with 6" ANSI2500 flanges for measurement of Lean MEG, ready for final testing.
6″ VFF V400 with 6″ ANSI2500 flanges for measurement of Lean MEG, ready for final testing.
6" VFF V400 with 6" ANSI2500 flanges for measurement of Lean MEG.
6″ VFF V400 with 6″ ANSI2500 flanges for measurement of Lean MEG.

Other meter sizes included a V270 for methanol measurement, several HF60s also for methanol and an LF03 measuring just 0.5 litres per hour of antifoam (40,000 to one range from the smallest to the largest, in case you’re wondering). They all use the VFF rotary piston technology with pressure balanced chambers to ensure accurate measurement independent of operating pressure.  The range of displacements is from 0.4ml up to around 860 ml.

Connection ratings were equally disparate, ranging from ANSI150 to API6A, matching pressure ratings from 16.5 to 690bar.

Litre Meter CEO Charles Wemyss said: “Many new technologies provide superb measurement at various pressures, flow rates and operating conditions but lack the ability to provide measurement when the going gets tough, the pressures get high and the rates get low, or in this case when the rate gets high.  For super low flows at challenging pressures, or when pulsing flow can’t be tamed, the VFF comes out on top.

“Hydrate, scale and corrosion prevention strategies provide protection during normal operation, start-up and shutdown.

“Litre Meter’s VFF flowmeter is ideally suited for use in the oil and gas industry and in particular for low flow / high pressure applications.

“Years of experience in chemical injection applications onshore and offshore have confirmed the instrument’s capability to reliably measure fluids under extreme conditions of both flow and pressure.”

What’s in a typical flow meter datasheet?

First, let’s have a look at what might land on your desk.  Later, we’ll review it line by line. Sign up for FlowSight, the Litre Meter newsletter.

A typical datasheet relating to a flowmeter is given as below – this one is based on a NORSOK format:

Flowmeter datasheet – Norsok layout.

This one is for the same meter but based on an ISA format (a version used by Litre Meter which uses S20.25 as it’s base):

Flowmeter datasheet – ISA layout, describing the same flowmeter.


This is an approximate layout, typified by NORSOK.

1 General

1.01 Type – a description of the flowmeter, by trade name and basic principle

1.02 Manufacturer – manufacturer’s name.

1.03 Design Temperature Limits – maximum and minimum design temperatures in suitable temperature units (°C)

1.04 Design Pressure Limits – maximum and minimum design pressures in suitable pressure units (bar gauge)

1.05 Estimated Pressure Loss – pressure drop at a specific flow such as maximum in suitable units (millibar)

1.07 Face to face dimension – complete assembly length in millimetres, with a tolerance

1.08 Mounting – type of mounting, in this case, In-Line but could be insertion, clamp-on etc.

1.09 Weight – dry, without fluids – in kilogrammes

2 Instrument Characteristics

2.01 Calibrated Range – flow rate range that the unit will be calibrated over – and units

2.02 Characteristic – an appreciation that not all meters are necessarily linear – some are non-linear such as orifice plates where the pressure drop is related to the flow rate by a square law, in this case linear – and linearised.

2.03 Meter factor – an estimated value of the number of pulses per litre – or other volume or mass unit

2.04 Accuracy – with percentage bounds and either proportional to the actual reading or FSD (Full Scale Deflection)

2.05 Linearity – with percentage bounds and either proportional to the actual reading or FSD (Full Scale Deflection)

2.06 Repeatability – with percentage bounds and proportional to the actual reading

2.07 Max Range limit – not necessarily the same as the maximum calibrated flow – describes the capabilities of the flowmeter

3 Meter Body

3.01 Nominal Size – normally relating the meter body size to the pipe size

3.02 Manufacturer model number – to precisely define the scope of supply

3.03 Process connection size and type – Size and flange or thread type, for example

3.04 Pressure rating – the rating of the flowmeter body in comparable units to 1.04

3.05 Face to face dimension – will match 1.07 in most cases

3.06 Body inner diameter – where appropriate

3.07 Sour service specification – nominated when appropriate – ISO or NACE in this example

3.08 Material, body – A specification for the material of the flowmeter body i.e. the main part of the meter

3.09 Material, Raised –

3.10 Protective coating/color

3.11 Other


4.01 Type – such as rotor and chamber or another description of the flowmeter internals and principle

4.02 Material, shaft – if any

4.03 Material, support – if any – this might refer to a turbine flowmeter part

4.04 Material, rotor

4.05 Material, bearing – if any, may include material and type

4.06 Material, Seal – not just the materials but may include seal type

4.07 Material, pick-up – i.e. sensor material, wetted, or not

4.08 No of pick-ups

4.09 Other


5.01 Type

5.02 Material

5.03 Connection

5.04 Other


6.01 Material

6.02 Connection up/downstr.

6.03 Up/downstream length

6.04 Tube inner diameter

6.05 Other


7.01 Type

7.02 Body/mesh material

7.03 Connection

7.04 Other

8              TRANSMITTER

8.01        Manufacturer model no

8.02        Mounting

8.03        Max distance meter/trans

8.04        Cable connection

8.05        Cable entry

8.06        Dimension

8.07        Material

8.08        Enclosure protection

8.09        Ex. classification

8.10        Protective coating

8.11        Indicator

8.12        Tamb

8.13        Totalizer

8.14        Output signal (note 9.02)

8.15        Communication

8.16        Recommended loop voltage

8.17        Transmitter loop voltage drop

8.18        Max loop current (fault condition)

8.19        Other – in this case describes more of the hazardous area ratings and standards – CSA, IECEx and ATEX

Why should I measure Scale Inhibitor (and how)?

Money, money, money – or, as we now call it, Flow Assurance, coupled with a low flow meter

Allowing scale to build up on the inside of the pipeline may seem fairly inconsequential. However, when the amount of scale is considered, (and referencing the image) it is immediately obvious that the expensive crude will slow down and pumping costs will soar. Sign up for FlowSight, the Litre Meter newsletter.
Scaling reduces the area of a pipe if scale inhibitor is not used
Scaling reduces the area of a pipe if scale inhibitor is not used – Stock image
Chemists will analyse the crude oil as it comes out of the well, sometimes years before production starts. From geotechnical surveys other technicians will determine the rate of oil output through the anticipated life of the field.  With this data the chemist will recommend what the concentration of the scale inhibitor should be.  The pressure of the well will determine at which pressure the inhibitor needs to be injected at. Day to day the temperature will vary according to the seasons, the weather and location of the measurement.
The analysis of the crude, unrefined oil will tell the chemist whether the pipe will start to scale up as a result of pumping the oil through a pipe to the ship or refinery.  Certain chemicals are then formulated to optimise and negate the scale.  There will be compromises between concentration of the fluid, application flow rates and storage availability.  If the concentration can be increased so that the tanks only need filling up once per month then that is preferred to once per fortnight. Inevitably this means that the flow rate is lower, and probably, the viscosity increases. Measurement range will also vary through the life of the field. It may start slow, then plateau a few years later and then tail off as the field winds down.  Additionally to this, the consistency of the unrefined oil will probably change from start to finish.  All of these variables can lead to a range of viscosities and a range of flow rates.
In summary, selection of the meter philosophy and specification is critical to successful measurement of scale inhibitor and future condition of the oil pipeline.

The VFF rotary piston flowmeter has been used for many years to measure scale inhibitor at a variety of flow rates, pressures and viscosities.

VFF flowmeter for chemical injection service, with FlowPod display

Electronic documentation – leading the way

Litre Meter now provides all documentation electronically for it’s manufactured flowmeters.  That’s not just a manual emailed to the client, either.  Each meter has a product label and includes a QR code and URL. At the website location there’s a minimum of a calibration certificate, quick start instructions and a full Installation and Operation Manual (IOM). Most will also have material certificates, hydrostatic test certificates, wiring diagrams and a function test cert. Sign up for FlowSight, the Litre Meter newsletter.

The product label is comprehensive, providing all calibration data.  The URL provides everything else the installation engineer might need. Using a smart phone and scanning the QR code is even more convenient.

Charles Wemyss, CEO of Litre Meter, says:”If a client needs any information emailed we just send the link. For larger projects with a number of flowmeters and larger documentation packages we include a single zip file for ease of downloading.  We’ve been providing this as part of our service since 2013 and our customers love it! This is a project dear to our hearts that cuts waste right down and provides our clients with a very quick and easy access point.  As far as we know, there is no other instrumentation company providing this level of data direct to their clients.”.

Litre Meter QR code allows remote access to documentation


20k meters – brochure available

Litre Meter have been making meters for higher pressures for over 3 decades. Our first 1,380bar unit was shipped in 1997.  We’ve now produced a brochure to cover these ratings.

Download the 20k VFF datasheet
20,000 psi rated VFF flowmeters – brochure

Litre Meter have been manufacturing flowmeters since 1975. We’ve always concentrated on the harder margins of metering typically at low flows and/or at high pressure. The VFF range has many uses in the oil and gas industry and meets the high specifications required. Outside of oil and gas we have manufactured these to 2,500 bar. We have recently noticed a trend towards 20,000 psi ratings and this brochure is in response to that.

Since 1997 Litre Meter has made numerous VFF meters for 1,380 bar in Oil and Gas applications and a reference list is provided at the end of this article.
The same design can be used on 22.5ksi (1,550 bar) with little modification.
The breakthrough in our design philosophy came in 2005 when we separated the measurement of the fluid from the pressure containment. We designed a measurement chamber that floats in the pressure vessel. This ensures accurate, pressure independent flow metering from 10 psi to 20,000 psi. The Pressure Balance Chamber is explained below.

Key Features

  • Rotary Piston/ Oscillating Piston type flow meter with a single moving part provides robust and low maintenance technology.
  • Suitable for low & high viscosity liquids at pressure ratings up to 4,000 bar (60,000 psi). 20,000 psi designs as standard.
  • Available materials of construction: 316L (UNS S31603), Duplex F51(UNS S31803), Super Duplex F53(UNS S32750)/F55(UNS S32760), 6Mo F44(UNS S31254), Hastelloy (UNS N10276) & Titanium (UNS R56400).
  • Connections: Autoclave, Grayloc Hubs, Galperti Hubs, Techlok hubs. More on request.
  • Communications: 4‐20mA HART, Pulse, MODBUS, Foundation Fieldbus, dependent on electronics and certification requirements.
  • Compact
  • Very Low Flow Measurement
  • Tolerant of particulate up to 100+ microns
  • Low pressure drop (<0.1 bar typical)

20K Flowmeters ‐ Applications and Rates

The VFF has successfully metered fluids such as oils, hydraulic fluids, corrosion / wax / asphaltene / demulsifier / pour point depressant (PPDs) /scale / hydrate inhibitors, biocides, oxygen scavengers, etc. for over 30 years. Meter bodies are produced in a variety of high grade materials which offer good chemical and environmental resistance.
Applications for flow‐rates as low 0.00013 litres/min (0.19 litres/day) have been metered within the offshore oil industry. The VFF flow meter provides exceptional rangeability with potential turndowns of up to 3000:1, dependent on operating viscosity.
The meters range in size from the smallest standard stock size, LF03 ‐ 18 L/Hr max, to the largest V270 ‐ 270 L/min max. Higher flow‐rate meters are available to special order.
An extensive range of meter designs and materials offers pressure ratings to 20,000 psi (1,380 bar). Higher pressure rating designs are manufactured up to 4,000 bar (60,000 psi). 20,000 psi designs available, as standard, up to HF60 and special designs can measure higher flow rates.

20K Flowmeters ‐ Meter Sizes

The VFF meter is not just one size, one specification. It’s a comprehensive range of carefully engineered devices to meet today’s standards in the most demanding oil & gas arenas. It’s truly a Versatile Fluids Flowmeter.

In the illustration below the smallest meter is typically housing an LF05 or LF15 rotor and chamber with FlowPod instrument and Autoclave Engineers MP connections.

The middle unit is a medium size meter, say, VFF4 with hub connections and FlowPod display.

The right‐hand meter also has hubbed connection sizes, FlowPod display but is larger to accommodates the HF60 rotor and chamber.

VFF Flowmeter Sizes and Connections.
VFF Flowmeter Sizes and Connections.

Pressure Balance Chamber

What Is a Pressure Balance Chamber?
Extensive testing by Litre Meter in 2005 proved that leaks occur over the top of the rotor at higher pressures. This is due to minute distortions of the cap. For example, at 700 bar the cap moves by just 0.02mm in the centre. Increasing the bulk of the cap still produces this movement. The effect on meter performance was the creation of a leak path for fluid that avoided the positive displacement of the rotor. This was equivalent to about a 3% inaccuracy at 700 bar. As a result, of this Litre Meter designed a pressure balance chamber for its VFF flowmeters so it could operate at extreme pressure and at low flow rates. The pressure balance chamber acts as a barrier, protecting the internal measurement components of the instrument from the high pressure conditions, preventing them from expanding and contracting under the immense pressure. NO DISTORTION MEANS ACCURATE MEASUREMENT AT ANY PRESSURE. All VFFs over 414 bar are fitted with this technology. It is identified by the letters PBC in the calibration certificate.
Key Benefits:

  • No distortion of the chamber at higher pressures.
  • Enables selection of optimal materials for the chamber to match the rotor i.e. PVD coated stainless steel or titanium.
  • Enables selection of optimal materials for the pressure vessel.
  • Enables construction of a duplex bodied flowmeter.
  • Swappable PBC for simplified sparing.

Flow ranges and references

All VFF flowmeters are custom calibrated across the customer specified min – max flow conditions and working viscosity. The minimum flow rates achievable are dependent on fluid viscosity. To see the achievable calibration ranges for each meter size please consult the table below. We can offer meters that range from 0.005 L/hr to 3,600 L/hr at 20K pressures to best suit your applications and with exceptional turndowns.

20K flow ranges

Areas of key significance:

  • Extended experience in measuring 20,000 psi in Oil & Gas applications.
  • World leaders in low flow and high pressure measurement.
  • High or low viscosity fluids flow measurement.
  • The Chemical Injection Specialists.
20,000 psi reference list
20,000 psi reference list VFF meters

Future developments

Litre Meter have already provided meters for 2,500bar. Offshore models at 22.5k & 25k are designed and 30k, 40k and 50k will be produced.
Litre Meter continues to innovate in the field of flow measurement. Recent successes include the LF05 and LF03 size meters, a new sensor, the FlowPod instrument and the FlowLabPro calibrator series. In the near term, expect to see lower flow capabilities, more calibrators and a low flow meter for any liquid type.

Queen’s Award 2016 – the story

We were recently interviewed for a story by our local Chamber of Commerce.  This is the result:

Litre Meter on the front cover of InBusiness
Litre Meter on the front cover of InBusiness

Specialist global flow measurement company Litre Meter has come a long way since its conception in 1975.

Set up in the attic of the Wemyss family home – with a calibration rig in the boiler house and a flow lab in the cellar – it was inevitable for a teenage Charles Wemyss to get involved in the family firm established by his father.

Litre Meter provided flow measurement engineering solutions that were ahead of its time and was set up to create one particular product, the Pelton Wheel – designed as a low cost economical meter for flow.

Charles said: “The product line was unusual at the time but now there are far more competitors to it. We still make it and it is still our company logo.”

From age 12 Charles worked in the business in school holidays but despite the cutting edge products and the company’s impressive initial success, he was uninterested in following in his father’s footsteps.

But when his father tragically died in a road traffic accident in 1978, the future of the company lay solely in the hands of Charles and his mother.

And they have done him proud.

Litre Meter has gone from strength to strength and cemented its presence as an international market leader in the flow measurement field, exporting products worldwide.

Now with a 16-strong team and manufacturing and selling from a converted barn in the North Marston countryside,  unprecedented sales over the past three years have recently been recognised by Her Majesty the Queen.

Litre Meter was awarded the UK’s highest accolade for sustained business exporting success – The Queen’s Award for International Trade.

Charles, now Litre Meter CEO, tells inbusiness: “We had two very successful years which were recognised in turnover and profit but this was a different recognition altogether. It was barely believable.

“It means as much abroad as it does here as a symbol of achievement. It provides a reassurance for our clients that we are of a certain standard.”

The award recognises continuous achievement, through sustained international trade. Litre Meter were praised for their enviable reputation, excellence in design and manufacturing, investment in British Engineering Excellence and service to the global oil and gas market.

“Our vision has always been to become the most respected specialist flowmeter measurement company in the world and this award reflects our continued commitment to that goal,” said Charles. “My father would have been immensely proud.”

In 2013 and 2014 Litre Meter enjoyed its most successful period ever, winning more orders in two years than in the previous six years combined.

This was driven by an increasing presence in the oil and gas sector, which has led to a substantial increase in export business. Over 65% of Litre Meter’s sales are exports.

Charles said: “There are some solutions we’ve got that no one else can do in the world so there’s no competition. We can do much lower flow rates and much higher pressures than most people and that means we can keep pushing those boundaries and keep innovating – that keeps us competitive.

“Our big market – where we sell more than half of our equipment – goes offshore to the oil and gas industries and they need those higher pressures and lower flows.”

But it hasn’t all been plain sailing in recent years, there have been many challenges along the way.

Charles recalled: “The most difficult time was the recession in early 2009. It was very tough. We had put together an ambitious plan and presented it to the staff in the January. We called it 5 x 14 – to triple our turnover in five years. Two months later we had to reduce all staff to a three day week.   The drop in the oil price really affected us then.

“We did get to 5 by 14 – we had £5 million worth of orders in one year.”

A key development that has led to this stupendous success was the manufacture of the Viscous Fluids Flow Meter (VFF), which was originally designed in the mid-80s.

“That’s the product that lifted us and took us to where we are now,” said Charles, who fully took over at the helm of Litre Meter 12 years ago.  “It was the right product at the right time. We spent many years refining the product to match the customer’s need, coupled with a worldwide expansion in the market we designed it for and the two things came together quite nicely.”

Litre Meter was sold in 2011 to a large conglomerate, but Charles still sees it as a family firm.

“My proudest achievement is keeping all these guys employed for such a long time. We might now be owned by an enormous American privately owned group but we are still 16 people in a field in North Marston.

“The success we’ve had – and what you don’t realise when you’re in the middle of it – was a big team effort.”

Charles accepted The Queen’s Award for Enterprise from Her Majesty at Buckingham Palace this summer.


ON YOUR CAREER: “I studied mechanical engineering at Sheffield. I graduated in the June/July and was working here at Litre Meter by the September.

“My tutor at Sheffield was head of the flow measurement lab but I had no interest in flow at all. It was the last thing I wanted to do. But I was sick of cleaning the hospital (straight after university) so I rang the MD of Litre Meter and he had just fired his chief engineer.”

DESCRIBE YOUR COMPANY: “We sell and manufacture flow meters and we vary our designs to meet customer requirements. A lot of the jobs are customised, bespoke, made to measure.”

JOINING THE CHAMBER: Litre Meter save money every year by using our International Trade team for export documents. “The service is first class,” said Charles.

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We are delighted to celebrate being one of the select businesses recognised as winners of the 2016 Queen’s Award for Enterprise – the UK’s highest accolade for business success.

Litre Meter awarded Queen's Award for International Trade
Litre Meter awarded Queen’s Award for International Trade

Our award was received for Enterprise in International Trade and was in recognition of achieving significant year-on-year growth of export sales from 2013 to 2015.  In turn, this helped us achieve record increases in turnover and profits resulting in a Compound Annual Growth Rate of 48%.


CEO Charles Wemyss: ‘As a very specialist company working on an international basis from the middle of a field in Buckinghamshire it is an outstanding achievement to be recognised at the highest levels for our success.’


Litre Meter was established as a family business in 1975 by the current CEOs father, where it moved to Buckinghamshire in 1978. Today, Litre Meter is recognised as the world’s premier Flow Measurement Specialist, employing home grown talent in a converted barn in North Marston.  Our highly engineered products are used in various industries throughout the globe, such as the Oil & Gas sector, where they can be installed on platforms in some of the deepest seas and most arduous environments. We pride ourselves in using local suppliers for our materials, where possible and are proud to be an active part of the UK’s engineering heritage.


Notes for Readers

  • 249 Queen’s Awards (QA) have been announced in 2016 for outstanding business achievement in the fields of International Trade, Innovation and Sustainable Development. Winners of The Queen’s Awards can expect an invitation to attend a special reception at Buckingham Palace.
  • QA winners can also use The Queen’s Award Emblem in advertising, marketing and on packaging for a period of five years as a symbol of their quality and success.
  • The awards are made annually by HM The Queen and are only given for the highest levels of excellence demonstrated in each category.
  • To find out more about next year’s awards visit the Queen’s Award website.
  • Litre Meter, based near Buckingham, UK, was established in 1975 and specialises in the custom design and manufacture of instruments for measuring and controlling fluids.
  • The company has particular expertise with offshore and sub-sea flow measurement and has supplied flowmeters for these applications throughout the world. The company’s VFF flowmeter was developed specifically for the petrochemical industry.
  • Litre Meter also pioneered the development of the Pelton wheel flowmeter, an accurate and versatile technology that has since been used across many industries to measure a variety of low viscosity liquids at both low and high flow rates.
  • Since 2011 Litre Meter has been part of the TASI Group of companies which includes AW-Lake, KEM and TRICOR.
    Rotary Piston Litre Meter flow meter with Hub connectors for high pressure flow measurement
    Rotary Piston Litre Meter flow meter with Hub connectors for high pressure flow measurement


    Litre Meter FlowPod flowmeter instrumentation
    Litre Meter FlowPod flowmeter instrumentation
Litre Meter operate out of a barn in the rolling Buckinghamshire countryside - Hart Hill Barn
Litre Meter operate out of a barn in the rolling Buckinghamshire countryside – Hart Hill Barn

The versatile VFF

Litre Meter was founded in 1975 as a manufacturer of industrial flowmeters. Today, the company still manufactures flowmeters, but with a slight shift in focus – more than 80% of its products are designed specifically for the harsh conditions of the offshore oil and gas industry.

The shift towards offshore supplying happened largely due to Litre Meter’s ability to engineer new products, as many offshore oil and gas rigs require custom-built flow measurement solutions for chemical injection; however, the ability to engineer new products has sometimes been a setback for Litre Meter, as the majority of orders would often require custom engineering despite the company’s extensive catalogue of standard products.

Litre Meter defines its company by the strapline, ‘Specialist flow measurement engineering’, representing four of its unique and client-oriented company principles:

  • Specialist: Litre Meter is a specialist manufacturing company, focusing solely on products for measuring flow, rather than level or pressure.
  • Flow: its products drill down into the finer flow details, such as flow rate and flow total.
  • Measurement: its products measure flow accurately – they are not flow switches or flow indicators.
  • Engineering: although it offers a catalogue of standard products, Litre Meter can engineer bespoke solutions for unique challenges.

The VFF series

Litre Meter’s shift in focus began a little over 25 years ago, when it first adapted a standard industrial flowmeter for use on a North Sea oil rig. The popularity and success of this custom device led to the eventual production of their flagship range: the Viscous Fluids Flowmeter (VFF) series.

The VFF series is hugely popular and very adaptable, but its standard range has still been largely overshadowed by a flood of custom orders – until recently. One of the innovations for the 2015 range of VFFs included a new by-product: the FlowPod. The device itself is two-wire and fully HART compatible, with stainless steel housing. It opens up the popular VFF series to an even wider range of low-flow applications, and gives even the most obscure requirements near-instant access to Litre Meter’s innovative engineering without the need for custom designs.

Introducing the FlowPod

Litre Meter decided quite early on that the FlowPod would be its only supporting instrument, and it has completely transformed the way the VFF range can be used.

The FlowPod mounts directly on the VFF flow meter.

Designed as Exi and Exd from the outset, the FlowPod was built in an enclosure small enough to be mounted directly onto the meter body, and gives Litre Meter an innovative method of incorporating extra functionality like reverse flow and redundancy measurement.
For Litre Meter, introducing the FlowPod to the VFF range was a great way to combine multiple design elements, gathered over 30 years of experience, to make an impressive and useful meter with a focus on utility plus weight and size reduction.
The 2015 VFF range includes more than 800 end-user drawings, representing more than 115,000 meter combinations and covering almost every conceivable possibility. While previously, around 80% of Litre Meter’s sales were for custom products, the introduction of the FlowPod means that only 5–10% of meters will now need any extra engineering at all. Most customers can simply access instant PDFs of general arrangement drawings, parts-list drawings and lifting diagrams, together with STEP files, as part of their Litre Meter quotation.
For Litre Meter, this means a faster sales cycle and more revenue; for the customer, it means much faster quotation, production and manufacturing times. 2015 has already been a big year for Litre Meter, and by raising its game and producing a range of meters without equals, it has truly cemented itself as a top-tier supplier of flowmeter technology to the chemical injection industry.

First published in Gas Technology Review www.gas-technology-review.com


Litre Meter VFF Range

LF03 chamber and rotor

We recently re-designed our popular VFF (Versatile Fluid Flowmeter) range of positive displacement flowmeters. The innovations in VFF technology make it ideal for bespoke flow measurement.

Innovations include a new compact size and design with reduced weight using high strength material specifications for high pressure applications. The new range of meters is suitable for low and high viscosity liquids at pressure ratings from 414 bar right up to 4,000 bar (60,000 psi). The range covers the measurement of fluids from 0.3 centistokes (cSt) to 100,000 cSt and flow rates of 0.0008 l/hr to 16,200 l/hr.

We have over 40 years’ experience in successfully designing and manufacturing bespoke flowmeters for extreme environments for the most demanding industries and applications.

The VFF series has been distilled into one series to meet the specific requirements of chemical injection flowmetering. The new 2015 VFF range uses the same ultra-reliable rotary/oscillating piston technology that Litre Meter has developed and refined over the past 30 years. With one moving part the flow meter is a robust and low maintenance component within a chemical injection system.

The VFF range has a wide of standard options so we can quickly respond to fulfill most chemical injection enquiries. A full drawing package is available detailing every option in either PDF or STEP formats.

Specifying the right meter for a system is now even easier to specify with a new VFF meter software, a step-by-step builder that takes the user through all the meter options available. When the meter has been selected the user can search the Litre Meter database of over 400 general arrangements and parts listing drawings. For more details the user can browse 3D STEP files for the correct meter to download and insert into the skid assembly.

Meters are constructed from 316L stainless steel, Duplex Super Duplex, titanium and 6Mo. Other materials are available on request. Standard connections include NPT, Autoclave, ANSI flanges, Grayloc hubs, Galperti hubs and Techlok hubs. Two wire Exia and 2/4 wire Exd versions are available and 4-20mA, HART7 communications is standard with new pickup sensor capabilities.

Other innovations in the 2015 VFF range include a new rotatable and positionable Exd approved display union, new sensing options with increased reliability, reverse flow detection and increased resolution.

We are excited about the new range. The new compact and lightweight design has been developed specifically for integration within chemical injection skids. Its footprint is further reduced because positive displacement flowmeters don’t require straight lengths of pipe in the system before or after the meter.

We have also responded to industry demands with regard to lifting requirements for offshore by adding lifting eyes manufactured from certified forged material to every meter that weighs 16 kg or more.


IMG_9572 LF03 white bgWe recently re-designed our popular VFF (Viscous Fluid Flowmeter) range of positive displacement flowmeters. The innovations in VFF technology make it ideal for bespoke flow measurement.

Innovations include a new compact size and design with reduced weight using high strength material specifications for high pressure applications. The new range of meters is suitable for low and high viscosity liquids at pressure ratings from 414 bar right up to 4,000 bar (60,000 psi). The range covers the measurement of fluids from 0.3 centistokes (cSt) to 100,000 cSt and flow rates of 0.0008 l/hr to 16,200 l/hr.

We have 40 years’ experience in successfully designing and manufacturing bespoke flowmeters for extreme environments for the most demanding industries and applications.

The VFF series has been distilled into one series to meet the specific requirements of chemical injection flowmetering. The new 2015 VFF range uses the same ultra-reliable rotary/oscillating piston technology that Litre Meter has developed and refined over the past 30 years. With one moving part the flow meter is a robust and low maintenance component within a chemical injection system.

The VFF range has a wide of standard options so we can quickly respond to fulfill most chemical injection enquiries. A full drawing package is available detailing every option in either PDF or STEP formats.

Specifying the right meter for a system is now even easier to specify with a new VFF meter software, a step-by-step builder that takes the user through all the meter options available. When the meter has been selected the user can search the Litre Meter database of over 400 general arrangements and parts listing drawings. For more details the user can browse 3D STEP files for the correct meter to download and insert into the skid assembly.

Meters are constructed from 316L stainless steel, Duplex Super Duplex, titanium and 6Mo. Other materials are available on request. Standard connections include NPT, Autoclave, ANSI flanges, Grayloc hubs, Galperti hubs and Techlok hubs. Two wire Exia and 2/4 wire Exd versions are available and 4-20mA, HART7 communications is standard with new pickup sensor capabilities.

Other innovations in the 2015 VFF range include a new rotatable and positionable Exd approved display union, new sensing options with increased reliability, reverse flow detection and increased resolution.

We are excited about the new range. The new compact and lightweight design has been developed specifically for integration within chemical injection skids. Its footprint is further reduced because positive displacement flowmeters don’t require straight lengths of pipe in the system before or after the meter.

We have also responded to industry demands with regard to lifting requirements for offshore by adding lifting eyes manufactured from certified forged material to every meter that weighs 16 kg or more.

Slim line customisation

Litre Meter’s ability to highly customise its meters has led to the company winning a significant order to supply meters to a company that produces hydraulic systems to the oil and gas industry. The fluid to be measured was Castrol Transaqua HT 2, with a viscosity of 3,95 cSt at 20 degree Celsius. The meters were bespoke slimline ones with a wide turn-down to allow for additional meters on a skid.

VFF positive displacement meters had to be made to operate at different pressures and flow ranges with different connections ranging from a VFF8 meter with a design pressure of 44 Bar, a scale of 0.3-30L/min with 25mm Female BSPP or equivalent size connections up to HP20 Flowmeters designed to work at a pressure of 950 Bar with a scale of 0.1-10L/min and 3/8” MP Autoclave connections.

All the flowmeters were located and certified for in Zone 2, Gas group IIB and Temperature class T3 so had to be EEx D or E. The minimum accuracy had to be within ±1.0% of full scale and the meters were constructed from 316SS quality stainless steel for all wetted parts.

The solutions provided were:

VFF8/690bar/AGPVD/V/9/16″AE MP

VFF8/1035Bar/AGPVD/V/9/16AE MP

HF20/207Bar/AGPDV/V/1″NPT all with


Significantly we were able to offer measurement over the whole of the flow ranges required which competing flowmeter manufacturers were not able to deliver. In addition, the bespoke slimline VFF8 1035bar on drawing enabled the end user to get an additional meter on the skid without having to increase the available space.

Litre Meter, Company of the Year

Text from Industrial Process News article, issue 622

It gives us great pleasure to present Litre Meter Limited with the prestigious and highly sought after Industrial Process News Flow Measurement ?Company of the Year?.

Speaking with CEO Charles Wemyss and Industrial Process News Editor Thomas Gill, we unveil the reasons why Litre Meter Limited has been selected for this prestigious award, why the company has been so successful over the past twelve months and how they have weathered the economic crisis.

Thomas explained: ‘If I’m being honest, it didn?t take much deliberation when selecting our Company of the Year. From our research, Litre Meter were head and shoulders above the rest in the category and have proven their worth especially over the past twelve months.

‘As we all know, weathering the economic downturn is crucial for all businesses and very difficult at that. But Litre Meter have managed to not only sustain their position in such difficult times but have also seen some encouraging signs, continually moving forward, and this was the real clincher for the team at Industrial Process News.’

Charles explained: The last time we won an award was back in 2005 and that was a springboard to part of our success, and we are hoping that this will generate the same outcome. It feels great to know that our hard work and dedication has been noticed. A job well done I say.

The past twelve months has been fantastic for us, as we have seen significant growth, acquiring more orders than the previous two years combined. This has particularly been driven by our presence in the Oil & Gas sectors. We are now in a position where we are very busy exporting, have a huge level of stock and have a large back log of orders that we are currently working on. Having so much business has given us a great deal of confidence.

To be honest the current economy hasn’t affected our business at all, which has allowed us to take strides forward in the industry. As the majority of our business is executed abroad, we haven’t had to shelter ourselves from any hardship in the UK. Our sales in the UK have risen and we are expecting, once the UK economy is stabilising, home-grown business to get even better, opening more doorways.

Our forecasts were significantly exceeded with a 29% rise in sales over budget and a 91% rise in bookings compared to 2012.

Our most successful product has been the LF05, part of the VFF range, which has been available for its first full year in 2013. Particularly successful in the Oil & Gas industries, the LF05 has pulled along other flowmeter sizes with its success, plus accompanying  instruments and accessories.


A simple construction with only one moving part and reed switch pulse output, the LF05 is a positive displacement flowmeter with 316 stainless steel body. With a PVD coated titanium rotor only, the LF05 is hazardous area approved as standard. Available with any end connections to your individual applications, the product has a flow range of 0 to 30 I/hr and is accurate to ±1% linearity, ±0.5% linearization and ±0.25 repeatability.

Other Litre Meter 2013 innovations have included: LF03 estimated at 60% flow rates of the LF05; a new connection type ? ½ inch OD tube; and QR codes on each meter, with links to material certs, calibration certs and instructions via the internet.

Looking ahead, we are aiming for more of the same. We currently have four times more orders, and we are looking to utilise our additional resources and information to increase production for the forthcoming years. With more resources available our ability to plan ahead has dramatically increased and we continue to grow and innovate.?

Company Profile:

Founded in 1975, Litre Meter Limited is a world-leading designer and manufacturer of flowmeters, which are installed on a wide variety of applications across the UK, Europe, America, as well as the rest of the world. Litre Meter works in a number of high profile industries including Oil and Gas, Aerospace, Automotive, Marine, Mining, Power Generation, and many others.

Litre Meter is a member of the TASI Flow Division, as well as the Institute of Manufacturing at Cambridge University, FPAL, Achilles, Institute of Measurement and Control and Northampton Chamber of Commerce. Litre Meter hold ISO9001:2008 approval.

Charles Wemyss, Chief Executive of Litre Meter Limited, commented: ?When flow measurement is critical, consult the specialists. Litre Meter has been leading the field since its founding, with a well established reputation for the design, manufacture and supply of flowmeters of all kinds.?

Firstly, Litre Meter pioneered the development of the Pelton Wheel flowmeter: an accurate, effective and versatile design suitable for many different fluids including acids, chemicals, fuels, spirits and water, at both high and low flow rates.

Then since 1986, Litre Meter has developed the popular VFF meter (literally, Viscous Fluids Flowmeter) for low flow & high pressure applications for the offshore industry particularly for chemical injection. And in 2011 the company supplied the largest ever chemical injection flowmeter order for the Gulf of Mexico.

Litre Meter?s portfolio for the UK now includes flowmeters of all kinds, including rotary meters, gas flowmeters, helical screw flowmeters, electromagnetic and ultrasonic flowmeters to handle a wide range of viscosities, flow rates and pressures, aggressive liquids and hazardous or adverse environments. They have particular expertise in measuring low flow rates and flows at high pressure.

‘To fulfil our customer’s needs in the UK we also distribute other flowmeters from many flowmeter manufacturers. For gas flow we offer Sierra thermal mass gas flowmeters, vortex flowmeters, Ritter gas meters, Hoffer turbine meters and Ritter gas sampling bags. Sierra also manufacture thermal mass gas flow controllers,’ added Charles.

For more information please don’t hesitate to contact one of the team on 01296 670200 or email: sales@litremeter.com. Alternatively, to view a full product portfolio or download spec sheets visit www.litremeter.com.



Chemical injection – from Africa to Arctic

Two articles in the current issue of Offshore magazine cover very different areas of the world ? West Africa and the Arctic.

They also cover very different scenarios. One is talking about ‘brownfield’ development – extending the life of existing fields and brining new reserves online through existing infrastructure. The other is focused on new technologies and challenges in safely exploiting hitherto unreachable reserves.

The common element is that both articles mention chemical injection as a key technology. This is, of course, an area in which Litre Meter has considerable experience.

Over the past year we have shipped a large number of meters to be used subsea, on a variety of chemicals, over a wide range of flows at high pressure and calibrated at specific viscosities. For example, Litre Meter rotary piston flow meters are part of systems used to control the amount of ‘antifreeze’ injected into pipelines at high pressure (430 bar) in subsea gas exploration on fields in the Caspian Sea and the North Sea.

‘Antifreeze’ fluids like methanol are used as thermodynamic inhibitors, which lower the freezing point of gas hydrate. They are injected into pipelines where there is a risk of hydrates (dew) forming then freezing at low temperature.

The antifreeze prevents gas hydrates solidifying as crystals and blocking pipelines – which can result in a costly shutdown and the risk of explosion or unintended release of hydrocarbons into the environment.

Litre Meter has also recently shipped flowmeters for use in chemical injection skids on a number of fields in the Gulf of Mexico and the Persian Gulf off Dubai. These meters are used in the flow measurement of wax dispersants and pour point depressants (PPD) to control their use to a very high tolerance.

Wax dispersants break apart and prevent the reformation of hydrocarbon sludge deposits and improve flow by reducing the viscosity of the fluid. PPDs are used to reduce the viscosity of oil and to maintain flow rate by preventing the build-up of wax crystals at low temperatures.

Sludge deposits are typically composed of varying concentrations of hydrocarbon, asphaltene, paraffin, water and inorganic materials. They are commonly found in storage tanks and vessels, production and transportation pipelines, process systems and hydrocarbon-producing formations where they have an adverse effect on the flow of crude oil from the well head.

Our expertise is nicely summarised in our new chemical injection brochure which highlights the enormous success of the VFF meter over the past few years in solving chemical injection measurement problems around the world.

With 3,000 VFFs in active use on chemical injection Litre Meter has demonstrated a depth of experience and knowledge that is unmatched in the low flow arena. The brochure provides further detail of the VFF range in one eight-page document.

Desalination provides metering opportunities

Desalination (the process of removing salt and minerals from water to make it potable) is mainly necessary in countries suffering water stress such as Oman, Kuwait and Saudi Arabia in the Middle East and in Australia, North Africa, Spain, the USA and China. It is also used on ships, submarines

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