Features The Type 75 relay uses signal pressure to accurately control output pressure over a wide range of flow and supply pressure variation. Under varying flow conditions output pressure is maintained by use of an aspirator tube, which adjusts the air supply valve opening in accordance with the flow velocity. A balanced supply valve, utilizing a rolling diaphragm, makes the relay virtually immune to changes in supply pressure. Maintenance is simple due to the unit construction, and the relay can be serviced without removing it from the line. Signal to output pressure ratios of 1:1, 1:2, 1:4 and 1:6 are available. Maximum output is 150 psig (10.3 BAR). Models Type 75 The basic relay offers excellent precision along with high forward flow rates. Type 75 High Relief Relays These relays provide extra fast “blowdown” for very rapid release of output pressure. The extra relief feature makes this relay suitable for cylinder return stroke actuation, air hoists, and similar applications requiring fast exhaust. To calculate negative bias relay output: Relay output = (signal pressure) - 4 psi bias x (relay ratio factor) where the relay ratio factor is defined as follows: Relay Ratio Factor Volume Boosting Gas Flow Control Valve Motor Loading Temperature Range -40˚F to +200˚F Type 75 Dimensional Drawing

P79 High Flow Air Relays The P79 1:1 Ratio High Flow Precision Air Relay brings additional precision and control to the BelGAS line of precision control products. The P79 relay is designed for applications where a precise control of flow is needed. This regulator offers low droop, high accuracy and fine adjustment sensitivity. The use of a rolling diaphragm provides greater sensitivity and improved accuracy. The balanced pintle minimizes output pressure changes caused by fluctuations in supply pressure. A version of the P79 for valve control applications is available. The P79 utilizes soft exhaust...

Type Standard P79 (w/Bypass Valve) Dead Band <0.4 psig < 0.6 psig (0.04 BAR) per 50 psig (6.9 BAR) change in supply pressure < 0.6 psig (0.04 BAR) per 50 psig (3.5 BAR) change in supply pressure <0.35 psig (0.02 BAR) per 100 psig (3.5 BAR) change in supply pressure <0.50 psig (0.02 BAR) per 100 psig (3.5 BAR) change in supply pressure Flow Capacity 40 SCFM (1150 LPM) @ 20 psig (1.4 BAR) signal and 100 psig (6.9 BAR) supply 40 SCFM (1150 LPM) @ 20 psig (1.4 BAR) signal and 100 psig (6.9 BAR) supply >125 SCFM (3500 LPM) @ 20 psig (1.4 BAR) signal and 100 psig (6.9 BAR) supply >125 SCFM (3500 LPM)...

Volume Booster Ordering Information Ratio Port Size (NPT) Type 75 Precision Relay Type 75 Precision Relay Fixed Negative Bias (4 psi) Type 75HR Precision Relay Type 75HR Precision Relay Fixed Negative Bias (4 psi) Tapped Supply Gage Port 0 Configuration 0 High Relief (P79HR) Versions 0 Standard B w/ Bracket * standard configuration P79V, has a A bypass valve, soft seat exhaust, epoxy finish and Tapped Vent Ports. Type 75 Option Ordering Matrix Replace last three digits of part number with digits from table below. Option 5 7 5 Epoxy Finish 005 075 7 Mounting Bracket 007