The Evolution of Flowmeters to the start of the Atomic Age

From the simplicity of Michael Faraday to the complexity of modern electronics, flowmeters have moved with the times and provide an accurate reflection of industrial progress. Most meters now used began, or finished, their main development by 1945.

The Nilometer is a well-documented type of meter alluding to it’s earliest known form. There must have been prototypes of this beforehand, definitely on a less grand scale. Maybe a brick left in a river bed allowed a local observer to draw a conclusion about the state of the water. That would have pre-dated the Nilometer by hundreds of years. What is certain is that they were very visual devices. Someone had to look at the meter itself to know the state of flow.

Leonardo da Vinci, in 1510 or so, observed the eddies trailing the bluff bodies of bridge piers. The frequency of shedding of the vortices is proportional to the flow rate. This physical action is exploited by the Vortex Flowmeter, first commercially available from Eastech in 1969.

Leonardo da Vinci observed the vortices shed from the bluff bodies of a bridge.

In 1738 Bernoulli published Hydrodynamica which described the conservation of energy in flowing fluids. He reasoned that as fluid speeds up it’s kinetic energy increased at the expense of static. He developed an equation for non-compressible fluids.  This theory is still applied for one of the oldest methods of flow measurement, orifice plates. The flow rate measured is a function of the pressure drop or loss.

Bernoulli’s equations formed the basis for one of the most popular types of flow measurement

Michael Faraday, in 1832, created an open channel electromagnetic meter at Waterloo Bridge. He used two large metal sheets as electrodes to try and ascertain the flow rate of the Thames. Due to the limitations of instruments at the time he was unsuccessful. By 1930 the principle was adapted for closed pipes and, just after the Atomic Age started, a commercial mag meter was available in the 1950s.

Michael Faraday delivering a Christmas Lecture at the Royal Institution in 1856 / Credits: Wikipedia

Although the first commercial ultrasonic flowmeter was used in the late 1950s earlier patents from the 20s and 30s set the tone. This one, from 1939, specifically references frequency and phase shift.

Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through the meter in a continuous flow by measuring frequency, phase-shift, or propagation time of electromagnetic or other waves, e.g. ultrasonic flowmeters

Coriolis flowmeters seem like the last word in flowmeter techniques but the origins date back to everyone’s friend Gustave Coriolis.  Apparently, Napoleon asked Coriolis why cannon balls never went straight.  Although this had nothing to do with what we now call the Coriolis effect, it did lead him to research the reasoning. By 1835 he had published research on the effect.

Gustav Coriolis, the original article
From Journal de l’École polytechnique, 1835

Patents evolved through the 50s and 60s to commercial offerings in the 70s.

A similar pattern can be traced for more traditional meters such as turbines and Positive Displacement flowmeters.

The Price Advantage, Standard meters at better prices

Litre Meter introduce the ”Price Advantage” series of VFF meters. The most popular VFF meters are now available in standard configurations at keener prices and shorter delivery times. These are the LF15, MF30, VFF4 and VFF8 sizes. 1/2″NPT threaded female connections, 316L stainless steel bodies and elastomer seals complete the specification. The internals are PVD coated stainless steel and using the standard calibration guarantees the best lead-time and price. All chambers are in-stock with 15cP calibration.

LF VFF Flowmeter
LF VFF Flowmeter with Direct Mounted FlowPod

LF15 0.75 to 90 l/hr, 15cP
MF30 1.20 to 180 l/hr, 15cP
VFF4 2.40 to 400 l/hr, 15cP
VFF8 4.80 to 800 l/hr, 15cP

As with all VFF meters the drawings are available at time of quote from a link. These 4 meter types are all:

  • 316L Rotary Piston VFF Flowmeter, PBC type. Pressure rating 530 bar.
  • Nitronic 60 Rotor and Chamber with ultra low friction PVD coating
  • Viton O’ring Seals
  • 1/2 inch female NPT
  • Direct mounted FlowPod display

Complete with:

  • Exd certification
  • Material Test Certificates
  • Hydrostatic Certificate and
  • Calibration Certificates

The seals can be swapped to Nitrile, EPDM or PTFE Encapsulated Viton O-ring Seals at no extra cost. Other materials such as Chemraz and Kalrez cost extra but are available on the same swift lead time.

Calibration can be customised according to the customer’s requirement at extra cost but still on the same 2 week lead time.


LF Drawings

MF30 Drawings

VFF4 and VFF8 Drawings

Certification etc

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