Water Flow Sensor (GPM for BTU Calculation)

The VFS flow measurement sensor combines the established vortex principle with the direct exposure of the sensor chip to the media which gives superior sensitivity and fast response. The VFS sensor detects the pressure pulsation generated by the vortices and converts the pulsation and temperature into an electrical output signal. The RPS sensor transforms the pressure and temperature of the medium into electrical signals. The pressure signals are linearized to compensate for temperature variations.

Technical specifications
VFS and RPS:
Connections - pipe: 1" straight male union thread  
Optional separate fittings: 1/2", 3/4" & 1" sweat tailpieces
(low-lead brass) and brass union nuts
Materials - body: brass, stainless steel or composite
- seals: EPDM
- sensor housing: composites (PPS, PA66)
- tailpieces low-lead brass
Performance
Suitable fluids: water, glycol solution
Max. percentage of glycol: 50%
Max. working pressure: 150 psi (10 bar)
Max. fluid temperature: 250ºF (120ºC)
Temperature measuring range: 32–210ºF (0–100ºC)
Temperature measurement accuracy: ±2°F (±1°C)
Temperature response time: < 1sec

Operating principle
The flow measurement is based on the vortex principle. The molded flow pipe (1) directs flow past the wedge shaped vortex generator (2), a series of vortices are generated periodically on each side of the wedge shaped body. These vortices move down steam giving rise to turbulence pressure variations, which are detected directly on silicon bulk micro machined chip (3) in the differential pressure sensor. The frequency of the pressure variations is proportional to the volume flow through the flow pipe (4).
VFS and RPS sensors have been constructed to withstand extended exposure to harsh environments with corrosion resistant coating on the sensor element, no moving parts and a robust brass or composite body.
RPS sensors utilize Micro-Electro-Mechanical Systems (MEMS) technology to quickly measure and deliver accurate pressure and temperature readings from a robust two-in-one sensor.
VFS sensors utilize Micro-Electro-Mechanical Systems (MEMS) technology and the principle of vortex shedding using an integrated bluff body vortex generator to quickly measure and deliver accurate flow and temperature readings from a robust two-in-one sensor. The bluff body is design to optimize the pulse strength of the pressure variations at the position of the differential pressure sensor.