The circular volume flow controllers are used for the reliable, precise, and fast control and stabilizing of contaminated volume flows in fume hood applications. All parts coming into contact with media flows are made of thermoplastic material. This makes the volume flow controllers particularly suitable for regulating chemically contaminated process air. Determination of the volume flow is carried out by differential pressure measurement at the integrated DIN-compliant Venturi tube. The design also guarantees very low pressure loss.
The design of the Venturi tube according to DIN EN ISO 5167-1, as well as the high quality demand made on the product, guarantee precise and perfectly repeatable measurement results even with lowest possible volume flows. The nominal diameter of the volume flow controller is chosen so that it can be connected to standard circular pipes without any adapters.
For the housing and installations, a PPs thermoplastic, highly chemical-resistant material is used. The volume flow control and flowmeters have completely enclosed housing in flange connection. The seal of the integrated throttle valve blade against the housing is achieved using a special, highly chemical-resistant elastomer material. The drive shaft of the control damper blade is fed through a 3-way adjustable condensation-proof O-ring seal in the volume flow controller housing and mounted in the counter bearing.
The ultrashort versions (HLBHA00200QF and HLBHA00250QF) have an oval damper blade with elastomer seal which has been positioned for improved flow in an exact, geometrically defined area of the diffusor. As a result, they have a drastically shortened installation length, precise differential pressure, and high control speed.
The volume flow controllers have also been tested and certified in the overall system (including automation station, operating unit, and sensors) for fume hood volume flow control according to EN 14175-6.