The Type 72 Relay features an adjustable bias pressure which enables users to obtain an output pressure which is the sum of a controlled input signal pressure plus the bias. The relay offers an exceptionally high flow capacity of up to 50 SCFM with minimal pressure droop. Output pressure is accurately maintained under varying 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 rolling diaphragm makes the relay virtually immune to changes in supply pressure. 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 request. Four adjustable bias ranges, from 0-10 psi to 2-150 psi are available.

The Type 72 Relay is used when high flow capacity is required in conjunction with a positive output pressure bias. Typical applications include; Gas flow control, Tensioning control, Clutch and brake controls, Volume boosting, Dancer roll loading, Calendar roll loading, Cylinder bucking control, and Valve motor loading.