WITT, manufacturer in the field of gas safety and gas process technologies, presents the precision metering valve (PMV).
Very small gas flow rates down to 30ml/min can be metered by the PMV. The precise flow adjustments can be made in the pressure range up to 290 psi using a rotary knob. Its spindle with 14 full rotations is generously sized to allow very fine flow gradations and has virtually no hysteresis. An alternative is a digital knob with 1499 divisions and a locking ring, this allows any target value to be set rapidly, precisely and with high repeatability.
However, the metering device boasts many additional special features, explains valve specialist Andreas Heyer, “We have redeveloped precision metering technology from scratch.” He continued, “A hollow-cylinder, sintered body forms the regulating core element.”
The PMV is superior to the needle valve in terms of service life. “The porous structure of the sintered body filters out unwanted particles from the gas as a side-benefit,” said Heyer. Static sintered bodies are not only insensitive to dirt, but are also self-cleaning when the valve is being set. Rapid clogging, as occurs with a needle piston, is rare. This has meant a corresponding lengthening of the fault-free service life.
WITT supplies the PMV fine-metering valve as a straight flow valve in block design with two rotary knob variants or simply as the valve cartridge. A choice of eight sinter inserts with different flow ranges and degrees of fineness is available. The valve is manufactured from brass and stainless steel, with nitrile rubber (NBR) seals. The design is extremely compact – the valve cartridge is less than 70 mm long and weighs only 54g.