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SSV Series

The all-rounder

The AR Valve of our SSV series 18, 19 and 20 (see graphic below) is a reliable device that automatically protects centrifugal pumps against wear, total loss and damage that can result from running dry, from cavitation or from operating under low-load conditions, generally suitable for pressures up to 140 bar (SSV18) or up to 180 bar (SSV19). As soon as the main flow falls below the required minimum flow, the valve opens its bypass to the extent that the required pump minimum flow is discharged even if the main flow is zero. The pressure in the bypass is reduced via an inte­grated throttle line with a bypass non-return valve. The SSV series 10, 11 and 12 work with pressure reduction in the bypass by throttles only.


The SSV series valves are suitable for all kind of liquid fluids, for example in

  • boiler feed water and condensate cycles of fossil and nuclear power plants as well as
  • combined cycle power plants
  • petrochemical and chemical industries
  • offshore applications
  • the production of renewable energies
  • the paper industry
  • steel mills
  • fire extinguishing systems
  • LNG applications
  • snow blowers and other industries

Operating principle

The AR Valve is flow-controlled, i.e. the non-return cone that controls the bypass via a lever, is raised solely by the main flow and into a determined position. Increasing main flow lifts, decreasing main flow lowers the cone position. The cone reaches its top end position at opera­tion flow. Via the lever, the non-return cone actuates the rotary valve in the bypass. When the cone is on its seat, the bypass valve is fully open. By opening the discharge line, the increas­ing main flow lifts the cone and the bypass is closed simultaneously. The valve is operating in a modulating way, i.e. it allows just as much liquid to flow through the bypass as is necessary to supplement the required minimum flow rate of the pump. The addition of main and bypass flow rate is always the requir­ed pump minimum flow. As soon as the main flow rate exceeds the pump minimum flow, the bypass is closed. Vice versa, the bypass is opened again when the main flow falls below the minimum flow.

Watch here the SSV Flow Animation.

Advantages at a glance

  • highly flexible application range
  • experienced, robust design

SSV 18 Dimensional drawing with optional DN4 branch:
main spare- and wear parts.

Advice for a long pump and valve life

Download the brochure

Schroeder Valves is a global specialist in designing and manufacturing reliable pump protection valves.

Find out more about our AR Valves and download the PDF brochure.