Flowmeters are used in a wide range of industries to measure the flow of a variety of materials. Fluids and gases all have different characteristics, meaning certain flowmeters are better suited to measuring certain materials than others.

A solvent is typically a liquid with a lower density than water. Whilst they vary in pressure and flow rates, solvents are best to be measured using the flowmeters mentioned below if you are looking for the highest level of accuracy and efficiency.

Rotary Piston meter

Also known as positive displacement flowmeters or PD meters, rotary piston meters measure volumes of fluid by repeatedly counting fixed volumes as the material passes in and out of the meter’s chamber.  Inside this chamber is an oscillating piston, dividing the chamber into compartments which contain an exact volume. This makes the rotary piston meter an efficient and accurate solution for monitoring and measuring flow rates.  It’s a versatile flowmeter, suitable for measuring a whole range of materials.

Pelton Wheel

The Pelton Wheel or the Radial Turbine meter measures and monitors the flow rate of all kinds of low viscosity liquids. It does this by using a large blade area with ferrites and a sensing coil.  As the flow enters the meter, the rotor begins to turn at a speed that is equal to the flow rate. The small sensing coil detects the ferrites on each tip of the rotor blades as they pass.  Its large blades and ultra-low friction bearings make the Pelton Wheel particularly useful when it comes to measuring low flows.

Vortex Shedding

A different type of oscillating flowmeter, Vortex Shedding meters induce fluctuations in fluids to create vortices. These vortices are detected by the meter to determine the fluid’s velocity and rate.  Vortex Shedding has been found to be one of the best choices of flowmeter when it comes to measuring steam and fluids at high temperatures but it is not limited to this. 

Ultrasonic meters

By using ultrasonic waves, ultrasonic meters can measure the flow rate of a variety of materials. These ultrasonic waves pass through the flow, measuring the travelling times and frequency shifts to determine the volume and rate. Ultrasonic meters are suitable for measuring the flow rate of water and other liquids, as well as a certain amount of solid content.  There are two types of ultrasonic flowmeters – clamped-on and inline – which differ simply in the way that they are installed.


Axial turbine flowmeters are used to calculate the average velocity of a fluid. A Turbine flowmeter makes accurate measurements by using a vaned rotor located inside the device. The vaned rotor is centred on a shaft and allowed to rotate on bearing as the fluid travels through the meter. The shaft is also supported by tube bundles or a cruciform, providing a degree of flow conditioning for the fluid also.

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. The units are manufactured in 316 stainless steel or titanium. They can measure pulsing flows. Suitable for solvent measurement. 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 solvent measurement up to 2" pipe sizes and larger and up to 10cSt. 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 methanol over a range of velocities. 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 solvent 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.