Disc check valve - RK | Gestra

GESTRA RK – Spring-Loaded Disc Check Valve

The GESTRA RK is a wafer-type check valve designed for installation between flanges. The disc opens via differential flow pressure and closes automatically by spring force, without the need for an actuator. With a spring, installation is possible in any orientation; without a spring, use is limited to vertical lines with upward flow.

Variants

• RK 76: DN15–DN100, PN6/10/16/25/40, ASME Class 125/150/300.
• RK 86 / RK 86A: DN15–DN200, PN10/16/25/40, ASME Class 125/150/300. DN15–DN100 also suitable for PN6.
• RKE 86 / RKE 86A: End-of-line version (e.g., vacuum breaker), only with metal disc. Not intended for safety valve applications.

Materials and Sealing Options

RK 86 uses body material 1.4317 up to DN100 and 1.0619 for DN125–DN200. RK 86A uses stainless steel 1.4408. Disc and internal parts are stainless steel; spring is 1.4571.

Available seat options:

• Metal seat, leakage rate C per EN 12266-1
• PTFE seat for corrosive media
• EPDM seat for water, condensate, and steam
• FPM seat for mineral oils, gases, and air

Applications

Suitable for water, steam, condensate, gases, air, and industrial fluids. Material selection depends on temperature, pressure, chemical compatibility, and seat leakage requirements. For clean steam, food, or pharmaceutical use, pickled versions of RK/RKE 86A are available.

Selection Considerations

DN selection should not be based solely on pipe diameter. Minimum flow must keep the disc fully open and stable. For pulsating flows (e.g., near compressors), pressure drop calculations and possibly special versions are required.

FAQ

Typical opening pressure?
For RK/RKE 86: 5 mbar up to DN100, 10 mbar for DN125–DN200 (with spring). Special springs available from 20 to 3000 mbar.

Is an actuator required?
No. Operation is automatic via flow and spring force.