Bellofram Type 72HR Positive Bias Booster Pneumatic Air Relay

Marsh Bellofram’s Type 72HR Positive Bias Booster Pneumatic Air Relay – High Relieving Version - is a positive bias booster pneumatic relay used when high flow capacity is demanded. The Type 72HR comes in four adjustable ranges with an outstandingly high flow capacity of up to 50 SCFM (1400 LPM) with minimal pressure droop. The output pressure of the Type 72HR is precisely sustained under fluctuating flow conditions by means of an aspirator tube, which adjusts the air supply valve opening in proportion to flow velocity.

A balanced supply valve utilizing a Bellofram patented internal rolling diaphragm makes the relay virtually immune to changes in supply pressure, while offering reliable performance over millions of cycles. Simple design makes maintenance easy, and the relay can be serviced without removing it from the line. The standard signal-to-output ratio is 1:1, but 1:2, 1:4 and 1:6 ratios are available on special request.