The Cla-Val 50-05 Pressure Relief, Air Release and Vacuum Breaker Valve is used to prevent surges during deep well pump start; and vacuum formation during pump shut-down operations. The valve is in the open position when the pump is started, discharging all of the air in the pump column and piping to the atmosphere. As the water begins to flow through the valve, the air release valve senses the change and closes, causing the main valve to close slowly through an adjustable restriction.
Hydraulic Pressure Control Valves - 50-05 & 650-05 Pressure Relief, Air Release & Vacuum Breaker Valve | Cla-Val
Cla-Val 50-05 / 650-05
Hydraulic pressure relief, air release, and vacuum breaker valve designed for deep well and pump station applications. Used during pump start-up and shutdown to mitigate hydraulic surge, prevent air entrapment, and avoid vacuum formation in pipelines.
Operation
At pump start-up, the valve remains open to discharge air from the pump column and discharge line to atmosphere. As water flow initiates, the air release mechanism closes, followed by gradual closure of the main valve via an adjustable needle valve to control transient effects.
Applications
- Deep well installations
- Pump discharge (delivery) pipelines
- Surge protection during pump start-up
- Vacuum prevention during pump shutdown
- Water networks with significant elevation differences
Construction
- Connection: Flanged
- Standard: ANSI
- Pressure Classes: 150 lbs, 300 lbs
- Materials: Bronze, ASTM A216 WCB, ductile iron
- Variants: 50-05 (full port), 650-05 (reduced port)
Selection Criteria
Selection is based on pipeline diameter, air volume during start-up, pump flow rate, operating pressure, closure rate, and installation location. Needle valve adjustment directly affects closure timing and transient response.
FAQ
Is this a simple air release valve?
No. It combines relief, air release, and vacuum breaker functions in a single assembly.
Where is it installed?
Typically installed on the pump discharge header or at locations requiring air evacuation from the water column.
Description
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