Check Valve - 81-18 | Cla-Val

Cla-Val 81-18 Check Valve

The Cla-Val 81-18 is a hydraulically operated, no-slam check valve designed for water distribution networks. The valve opens when inlet pressure exceeds downstream pressure and achieves drip-tight closure upon pressure reversal, preventing backflow.

Operation

Downstream pressure is routed to the cover chamber via control tubing. Gradual opening minimizes hydraulic surges, while the hydraulically controlled closure ensures drip-tight shutoff without sudden slam events. The valve operates automatically, utilizing system line pressures.

Technical Data

• Type: Hydraulically operated no-slam check valve
• Model: 81-18
• Connection: Flanged
• Standard: ANSI
• Pressure Classes: 150 lbs, 300 lbs
• Body Materials: Bronze, ASTM A216 WCB, ductile iron
• Operation: Automatic, pressure-actuated
• Sealing: Drip-tight closure

Applications

Suitable for water pumping stations, booster pump discharge lines, industrial water networks, and installations where flow reversal may cause hydraulic shock. Commonly used in municipal water supply, process water, and industrial utility systems.

Selection Criteria

Valve selection should be based on required flow rate, available differential pressure, ANSI flange class, pipeline velocity, and surge mitigation requirements. For large diameter pipelines or high flow velocities, surge analysis is recommended.

FAQ

Is external power required?
No. The valve operates hydraulically using system line pressures.

When does the valve close?
Closure occurs when downstream pressure exceeds inlet pressure.

How does it differ from a standard check valve?
Closure is controlled via a cover chamber and control lines, reducing slam and associated pressure transients compared to conventional check valves.