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SchuF Automatic Recirculation Valve

SchuF Automatic Recirculation Valve protects centrifugal pumps against low-flow operation by combining check-valve and minimum-flow bypass functions in one self-actuating valve. Request a quote for SchuF Automatic Recirculation Valve from AxFlow.

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Product features

  • Automatic minimum-flow protection → helps protect centrifugal pumps during low-load operation.
  • Integrated check function → reduces the need for separate reverse-flow protection.
  • Self-actuating operation → no external electrical signal or instrument air is required for the basic function.
  • Modulating bypass action → recirculates only when main process flow falls.
  • Single-body solution → can replace several components in a conventional bypass arrangement.
  • DN 25–250 standard range → covers a broad range of critical centrifugal-pump duties.
  • Pressure classes up to ASME 2500 → supports demanding high-pressure applications.
  • High-pressure and slurry variants → extends application flexibility for severe service.
  • Application-specific sizing → matches bypass flow to the pump minimum-flow requirement.
  • AxFlow support → simplifies selection, spare-parts planning and lifecycle service.

Product description

Centrifugal pumps can be damaged when process demand falls below the minimum stable flow required for cooling, hydraulic stability and safe operation. The SchuF Automatic Recirculation Valve provides a compact way to maintain this minimum flow while also preventing reverse flow, making it relevant for boiler-feed water, cooling-water, refinery, chemical, pulp and paper, marine and other critical pump services. It is particularly useful where operators want to avoid a continuously open recirculation line and the associated energy loss.

The valve reacts mechanically to changing main-line flow. As the main flow decreases, the internal disc moves toward its seat and the bypass element opens a recirculation path; as demand rises, the bypass closes progressively and the main outlet remains available for process flow. Because this action is self-contained, no external electrical signal, instrument air or separate control valve is required for the basic minimum-flow function.

Current SchuF and AxFlow data describe the range from 1 inch (DN 25) to 10 inch (DN 250) and up to ASME Class 2500, with other configurations available on request. The design combines check and bypass functions in one body and is available in variants for high-pressure service and demanding multiphase or slurry applications. Exact sizing, bypass flow, pressure class, materials and trim must be selected from the pump curve and process conditions.

By replacing several components of a conventional bypass arrangement with one engineered valve, the solution can reduce piping complexity, auxiliary control hardware and maintenance points. Maintaining the specified pump minimum flow helps reduce the risk of overheating, cavitation-related damage and unstable operation, while closing the bypass when full process flow is available avoids unnecessary recirculation energy. AxFlow can support valve sizing, material selection, spare parts and lifecycle service for the installation.


It maintains the minimum flow required by a centrifugal pump when process demand falls. The valve opens a bypass path automatically while also providing reverse-flow protection. This helps protect the pump without a continuously open recirculation line.
The basic minimum-flow function is self-actuating and does not require an external electrical or pneumatic actuator. Its internal mechanism responds directly to changing main-line flow. Any project-specific instrumentation or accessories should be confirmed during selection.
Current SchuF and AxFlow data list standard sizes from DN 25 to DN 250. Pressure classes are available up to ASME Class 2500. Larger, special or severe-service configurations should be confirmed with AxFlow.
Typical applications include boiler-feed water, cooling-water, refinery, chemical, pulp and paper and marine pump systems. They are especially useful where a centrifugal pump must retain a guaranteed minimum flow during low demand or start-up. Process conditions and the pump curve determine the correct valve configuration.
Selection starts with the pump minimum-flow requirement, normal operating flow, pressure, temperature and fluid properties. The bypass capacity and valve trim must then be matched to the pump and system. AxFlow can help identify the correct SchuF configuration and provide a quotation.
UAB AxFlow