Diaphram-Operated Lift Check Valve - 81M Spring-Loaded | Cla-Val

Cla-Val 81M Spring-Loaded Diaphragm Check Valve

The Cla-Val 81M is a lift check valve, spring-loaded and hydraulically actuated via diaphragm. It is primarily specified in marine sprinkler and AFFF systems to prevent reverse flow in hydraulic signal or actuation lines.

Operation

This valve is an internally ported diaphragm actuated hydraulic check valve. Internal porting and diaphragm actuation enable the valve to function as a control element in both open-valve and closed-valve loop piping. In standard Cla-Val diagrams, two 81M valves are installed per loop to ensure the highest available pressure signal is applied to the Magazine Sprinkler Valve.

Technical Specifications

• Type: spring-loaded diaphragm operated lift check
• Function: reverse flow prevention
• Design: internally ported
• Application: hydraulic actuation circuits
• Typical size (engineering sheet): 3/8"
• Use case: Dry Type Magazine Sprinkler Systems
• Systems: sprinkler, AFFF, seawater sprinkler control loops

Applications

The 81M is selected for circuits where check function is required not only for main water supply but also for control pressure signals. Typical applications include:

• magazine sprinkler systems
• dry and wet type sprinkler loops
• AFFF foam systems
• hydraulic actuation lines
• marine fire protection circuits

Selection Considerations

Selection should address loop function, required actuation signal, compatibility with AFFF or seawater, connection requirements, and fire protection system specifications. Response delay or minor reverse leakage can affect main valve actuation logic in these applications.

Maintenance

Inspection should include internal port cleanliness, diaphragm condition, spring operation, and sealing under reverse pressure. For AFFF or seawater service, check for deposits and elastomer chemical compatibility.