Water

Litre Meter specialise in the design, manufacture and supply of flowmeters. The unique Pelton wheel based meter design ensures an inherent reliability which has been proven in more than three decades of operation. Listed below are all the flow meters within our range that are suitable for water flow:

Different fluids have different characteristics; they vary in given pressure, temperature, density, conductivity, composition to only mention a few. 

Water is the transparent fluid made up of hydrogen and oxygen, forming the world’s streams, lakes, ocean and rain. It’s a liquid at standard ambient temperature and pressure but can also be seen in a solid state (ice) and a gaseous state (steam), as well as existing as snow, fog, dew and cloud. 

Our range offers a number of different flow meters that are suitable for water, including: 

Rotary piston meter

Rotary piston meters, also known as positive displacement flowmeters (PD meters) measure volumes of fluid by counting repeatedly known fixed volumes as they go in and out of the meter’s chamber.

The chamber contains an oscillating piston which divides the chamber into compartments containing an exact volume, meaning that the volume can be monitored and measured easily.

Perfect for measuring low flow, high pressure chemicals or hydraulics, positive displacement flowmeters are used for most fluids including water, as well as polyisobutene. 

Pelton wheel

Also known as a radial turbine, the Pelton Wheel measures and monitors flow rates by using a large blade area with ferrites and a no-drag sensing coil.

As the flow goes into the meter, it is directed by a jet onto the rotor which turns at a speed in proportion to the flow rate. The small sensing coil detects the ferrites of each of the rotor blades’ tips as they pass.

Due to the large size of each blade and ultra-low friction bearings, this flowmeter is ideal for jobs that require the measurements of very low flows.

Vortex shedding

Like all oscillatory flowmeters, vortex shedding detects provoked vortices made from the fluid to determine its velocity and rate. 

Vortex shedding uses the fluid’s own properties, like its pressure, density and viscosity, to induce fluctuations that create the vortices that help to calculate the volumetric flow rate. 

Due to its ability to measure low viscosity liquids and volumetric flow rate, vortex shedding has been found to be one of the best choices to measure water or other condensates accurately. 

Ultrasonic 

To determine the flow velocity, these flowmeters use ultrasonic waves that pass through the flow measuring the travelling times or the frequency shifts. 

There are two types of ultrasonic flowmeters - clamped-on and inline – and they differ by the way they are installed. 

Ultrasonic flowmeters can measure water and other liquids, as well as a certain amount of solid content. 

Turbine 

Turbine flowmeters are used to calculate the average velocity of a fluid, detecting the vaned rotor as the fluid travels through the meter to make an accurate measurement. 

Found inside the meter, the vaned rotor is centred on a shaft and allowed to rotate on bearings. The shaft is also supported by tube bundles or a cruciform which provide a degree of flow conditioning for the fluid, improving the accuracy of the reading. 

It’s a great choice of flowmeter for water due to its wide size range and its excellent precision. 

Helical screw

A helical screw flowmeter is controlled by the fluid itself – as the fluid flows through the meter, the helical screws inside are forced to rotate. 

Inside, there are two – normally identical - counter rotating gears that form a continuous constant volume cavity, meaning that the flow rate of a fluid can be determined by the known volume within the cavity per revolution. 

Very little force is needed to rotate the gears ensuring that pressure drop is kept to a minimum, and as a result they are a great option for higher viscosity fluids, too.


VFF Rotary Piston Positive displacement flowmeters, also known as PD meters, measure volumes of fluid flowing through by counting repeatedly the filling and discharging of known fixed volumes. A typical positive displacement flowmeter comprises a chamber that obstructs the flow. Inside the chamber, a rotating/reciprocating mechanical unit is placed to create fixed-volume discrete parcels from the passing fluid. In the VFF the rotor is basically a disc shape with an annular groove on its underside capable of holding and transporting flow from the chamber inlet to the outlet i.e. a rotary piston. Water meters in the UK have traditionally used rotary piston technology. The VFF size range goes much lower than domestic water meters and has been designed for higher pressures and in corrosion resistant materials. The benefit of this technology that it can measure water based chemicals in various concentrations including water only. They can measure pulsing flows. 0.01 to 33,000 l/hr. +/-0.5% accuracy, +/-0.25% repeatability.
Pelton Wheel Also known as a radial turbine the highly efficient Pelton Wheel meter has some major advantages. The very large blade area compared with the flow inlet port size produces an exceptionally wide range flowmeter which can measure very low flows. The flow through the inlet of the meter is accurately directed onto the rotor which rotates at a speed in linear proportion to the flow rate. A small sensing coil detects the ferrites mounted in the flow meter rotor blade tips as they pass. No drag is imposed on the rotor which assists in the measurement of extremely low flows. Sapphire bearings provide a very low friction mechanically-robust bearing with long life characteristics. Turndown can be as high as 280:1. Ideally suited for water measurement up to 2" pipe sizes and larger. 0.003 to 500 l/min; ±2.0% of reading (also 1.0%); some models suitable for flow measurement at higher pressure.
Vortex Vortex and other types of "oscillatory" flow meters utilize the behaviour fluid oscillations in order to derive flow rate. This technology works by inducing fluctuations in the fluid properties such as pressure, density or viscosity which can be converted into a flow rate. These flowmeters are normally calibrated on water. No moving parts and relatively tolerant to particulate flow these find many applications where temperatures are high or where other more traditional flowmeter technologies are out of spec. +/- 1% rate, 1/2" to 8" and insertion.
Ultrasonic Ultrasonic flowmeters measure the travelling times (transit time models) or the frequency shifts (Doppler models) of ultrasonic waves in a pre-configured acoustic field that the flow is passing through to determine the flow velocity. The Sierra range of ultrasonic (transit time) Innovasonic devices are available, click for details. Litre Meter has access to other ranges but the Innovasonic is relatively unique as not only are fixed and portable ultrasonics available but also insertion devices for tougher applications. Ultrasonic flow meters can measure water and other liquids over a range of velocities and with a certain amount of solid content. 25mm to 10000mm;±1.0% of reading (also 0.5%); 0 to ±40 ft/s (0 to ±12 m/s).
Turbine Inline 'axial' turbine flowmeters are velocity measuring devices - they measure the average velocity of a fluid flowing through the body of the meter. Mounted within the body of a liquid turbine flowmeter is a vaned rotor. The rotor is centred on a shaft and allowed to rotate on bearings. The shaft is supported in the housing by tube bundles that also provide a measure of flow conditioning for the fluid stream. Good for water flow metering. Wide size range and excellent accuracy. 0.24-17 up to 3028-56775 litres/min. Overrange 150% intermittent. ±0.25% reading - typical. ±0.1% repeatability.
Helical Screw Positive displacement flowmeters, also known as PD meters, measure volumes of fluid flowing through by counting repeatedly the filling and discharging of known fixed volumes. A typical positive displacement flowmeter comprises a chamber that obstructs the flow. Inside the chamber, a rotating/reciprocating mechanical unit is placed to create fixed-volume discrete parcels from the passing fluid. The helical screw principle uses 2 counter rotating gears to form a continuous constant volume cavity. The OMK is a stainless steel version suitable for water flow metering. 0.2 to 100 litres per minute, +/-0.5 to +/-2% accuracy, +/-0.2% repeatability. Other versions like the OMG and OME flowmeter can be selected for suitable adhesives and resins; +/-0.1 to +/-0.3% accuracy, +/-0.01% repeatability. 0.1 to 7500 l/min.
Digmesa From the stringent hygiene requirements of the manufacturing process to simple dispensing measurement at point of sale the industry relies on flow measurement. The Digmesa range of technologies offer cost effectives solutions for many applications. Whether you require beer or cold drinks dispensing, cellar auditing systems, coffee makers (industrial and domestic) or flowmeters for vending machines these meters can help. Ideally suited for water flow measurement and typically used for batching applications. From about 30 ml/min to 30 litres per minute. Contact factory for details. MOQ 100 units. +/-2% reading, +/-0.25% repeatability.