Reduced-pressure-zone backflow preventer BA, RPZ-Valve

Fluid category 4 safety valves

KEMPER RPZ backflow preventers type BA protect drinking water from non-potable water up to and including fluid category 4.

Definition of fluid category 4 based on DIN EN 1717

Fluid that represents a health hazard for human beings through the presence of one or more toxic or very toxic substances or one or more radioactive, mutagenic or carcinogenic substances.

Practical use examples:

  • Chemical mixing means, e.g. disinfectants, fertilisers, etc.
  • Heating filling device, water with inhibitors
  • Non-certified softening systems
  • High-pressure cleaners

You can find more information on choosing the right safety valves in our guidebook.

Go to safety valves guidebook

How does an RPZ backflow preventer work?

RPZ backflow preventers are based on a three-chamber system with supply pressure, medium pressure and back pressure zones. The differential pressure controllers of the protection cartridge on the inlet side and the check valve (RV) on the outlet side ensure reliability and a high level of safety.

1. Rest position (under operating pressure)

If no removal of water occurs, the check and and bleeder valve are closed on the inlet and outlet sides.

2. Flow position

When water is being removed, the check valves on the inlet and outlet sides are open and the bleeder valve is closed.

3. Disconnection position

In the event of siphon backflow, the pressure on the inlet side drops. The bleeder valve reacts before the differential pressure falls below 140 mbar. The check valves on the inlet and outlet sides close, bleeder valve opens.

Terminal RPZ backflow preventer type BA

Discover our terminal RPZ backflow preventers type BA for use cases with flexible connections.

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