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W.A.S offers a wide range of flowmetering technologies for gas applications.

Thermal Flowmeters


Thermal mass flow meters generally use combinations of heated elements and temperature sensors to measure the mass flow of a fluid. The fluid temperature is also measured and compensated for. They provide a direct mass flow readout, and do not need any additional pressure temperature compensation over their specified range.

Thermal mass flow meters are used for compressed air, nitrogen, helium, argon, oxygen, natural gas. In fact, most gases can be measured as long as they are fairly clean and non-corrosive.

W.A.S. supplies 2 basic kinds of thermal mass flowmeter devices

Vortex Flowmeters

Vortex flowmeters make use of the Karmansch vortex principle. The frequency of the created vortices behind the bluff body is used for measuring the flow of the medium. A capacitive sensor detects the local low-pressure created by the vortices. This information is then used to compute the flow.

Vortex flowmeters are applicable for gases, steam and liquids

Vortex products

Differential pressure

By reducing the diameter of a line, a differential pressure is generated in the flow. This difference is in quadratic proportion to the volumetric flow of the medium. Orifice plates, nozzles or venturi tubes are used to reduce the pipe diameter. Pitot tubes use the same principle by measuring the stream-up and -down side.

Differential pressure systems are:

Ultrasonic Flowmeters

This Principle uses an acoustic signal, sent and received by one or multiple transmitters. The signal is directed alongside and against the flow-direction, the runtime-difference between the 2 signals is proportional to the flow-speed. By additionaly considering the process-pressure, process-temperature and pipe-dimensions, the flow can be calculated.

Ultrasonic Flowmeters are available as Inline-devices or clamp-on designs

Coriolis Flowmeters

The coriolis measuring principle uses the coriolis force, an inertia force. The coriolis force appears in rotating reference systems, additional to the centrifugal force. It's value is proportional to the mass of the moved body. The moving mass will be forced into oscillation in 1 or 2 metering tubes across the direction of movement. The coriolis forces which occur here, influence the oscillation of the measuring system, which are the basis of the measurement. Depending on the layout of the system, density can also be recorded.

Coriolis products