Moore Products 67R25 Series 67 Precision Relays | 4" Hg vacuum to 35 psig (0.14-2.4 bar)Series 67 precision relays are narrow-band pneumatic controllers; with each one having an adjustable setpoint. These relays provide a high gain, repeatable output in response to changes of the pneumatic input.Series 67 relays are ideally suited for use as: Narrow-band proportional controllers, for direct process control Pneumatic safety and interlock switches Primary amplifiers, for precise operation of electrical pressure switchesA typical application of these high-gain relays is to activate a fail-safe valve when any of several process variables exceeds certain limits, potentially causing an unsafe condition. Model 67 relays are connected in series to monitor pneumatic signals, which are proportional to each process variable. Supply air to the normally closed (air-to-open) shutdown valve is connected through each of these relays. When all of the process variables are within operating limits, the supply air will pass through each relay - holding the valve open. When any variable exceeds its set limit, the supply air will be shut off, and the relay output will be vented to close the fail-safe valve.