Automatic Recirculation Valves protect centrifugal pumps from damage that may occur during low-flow operations. Minimum flow protection is accomplished with an automatic, modulating bypass that assures smooth pump operation between the minimum and maximum flow point on the pump curve.
No external power source is required. These valves are self-contained and simplify the system design and installation. Sizes range from 1 inch to 24 inches, including ANSI Class 150 through 2500 lb. Valve internals are stainless steel with housing in carbon steel, stainless steel, or special machinable alloys.
The primary function of AUTOMATIC RECIRCULATION VALVES is to assure the Minimum continuous Flow (Qmin) required by the centrifugal pump during all operating conditions. Centrifugal pumps can be damaged due to cavitation and over-heating during ‘low flow’ and ‘no flow’ operations.
OPERATION OF AUTOMATIC RECIRCULATION VALVES
The valve combines the functions of:
- Main Flow check valve disk that is flow sensitive and modulates with the process flow over the full pressure range. The Main Flow check valve disk is designed as a Non-Return Check Valve to prevent reverse flow from process.
- Bypass valve head that controls the designed bypass flow (Qmin). The Bypass valve head modulates with the process demand flow to assure Qmin and to ‘shut off’ when the process demand is in excess of the required Qmin.
- Throttle that internally provides pressure reduction for the bypass flow.
When the Main Flow check valve disk is on the valve seat, the Bypass valve head is 100% open.
In this position there is no flow to process and the open Bypass provides the Minimum continuous Flow (Qmin) to protect the pump from ‘low flow’ and ‘no flow’ damages.
As the process control valve begins to open – the Main Flow check valve disk will move and begin to allow flow to the process. The Bypass valve head will begin to close. In this modulating function (partial process flow and partial bypass flow) the Minimum continuous Flow is assured.
As the Main Flow check valve disk continues to open due to the increase in process demand the Bypass valve head will ‘shut off’ when the process demand is in excess of the Minimum continuous Flow. This allows all the pump energy to flow to the process demand.
- No external power source is required
- Self-contained for simplified system design and installation
- Size range:1” through 24”
- ANSI class:150 through 2500
- Engineering Assistance for Valve Selection
- Specific Valve Design According to:
- Pump/Process Data
- Pressure Rating/Connections
- Spare Parts
- Modification, Repair, and Reconditioning of Valves: Disassembly/Part Replacement/Reassembly
Experienced service engineers are available on call for worldwide start-up assistance, training, and repair.
All repairs are supervised by specialists with direct access to factory engineering personnel.