ALADCO 302502 1/4" NPT Nu-Check Valve with Override, Viton Seals
The Aladco® Nu-Check® valve is a normally closed check valve that can be either overridden manually or by air piloting to allow two-way flow. The tightly sealed Nu-Check® valves are used on pneumatic devices to prevent air from flowing towards the ball check upon loss of pilot pressure which will prevent the device from drifting. The Nu-Check® valve, designed specifically for pneumatics, is a patented Aladco® product. It was the first check on the market with both manual and pilot release capabilities. The unique bubble-tight seal keeps devices from drifting towards the “checked” position in the event of pressure loss or fluctuation. To release the seal, press the manual override button or operate the pilot. A typical use of a Nu-check® valve involves combining it with a directional control valve to restrict when air is allowed to flow from ports of a pneumatic device. With an appropriate combination of directional control valves and other pneumatic components, a cylinder position control system using Nu-Check® valves can accommodate for both normal position control as well as rapid motion stoppage and position holding. Two example schematics are shown to illustrate potential uses of the Nu-Check® valve. Figure 1 shows an example of a system using a single Nu-Check® valve that will prevent the cylinder or load from falling upon pressure loss or upon loss of power to directional control valve. Figure 2 shows an example of a system using two Nu-Check® valves that will stop the cylinder in from moving in either direction upon pressure loss or upon loss of power to directional control valve. Aladco® highly recommends the use of spring centered 3 position 5 way centered vented valves for directional control with the use of Nu-Check® valves.