Norgren has designed an isolating system that helps users comply with the machine air monitoring requirements of AS4024.1-1996. The standard requires that machine air supply shall be effectively isolated before maintenance is performed.
The P645 and P745 monitored valves have been developed from soft-start dump valves. They allow air system pressure to be slowly introduced on machine start up. This avoids pre-exhausted cylinder start up, a situation where cylinders stroke at uncontrolled speed on first start up due to lack of air system back pressure. The soft-start valve switches to full flow at a predetermined pressure, typically 50% of system pressure.
The isolating valves have a valve spool that is positively monitored by a micro switch on the valve. The micro switch confirms the spool has shifted into the isolated position. They can handle pressures of between three and 16 bar and can operate from -20°C to 50°C.
As the valves are based on modular air preparation dump valves they can be easily fitted to filter regulator units. For AS4024.1-1996 Category 4 applications that require dual monitoring, two monitored dump valves can be easy mounted and piped in series using Norgren quick clamps or mounting yokes. This modular system eliminates the need for fittings and pipe work between air preparation units and isolating valves. Both Norgren P645 and P745 are poppet type valves that dump downstream air rapidly. The internal poppet design valve offers good sealing characteristics and offers good resistance to airline contaminants.