Axial Check Valve – Fast backflow stop with lowest pressure loss
The axial check valve type RD100 – also referred to as a nozzle check valve – prevents backflow in piping systems with minimal pressure differential. Thanks to the axial flow path and the spring-loaded closure element, the valve closes within fractions of a second, before full backflow can occur. The result: effective protection against pressure surges (water hammer) with the lowest possible flow resistance.
Operating principle – Why nozzle check valves close faster
In a nozzle check valve, the closure element moves axially along the flow axis – not sideways like a swing check valve or vertically like a lift check valve. The short closing stroke of the spring-loaded disc enables an extremely fast response to pressure reversal. At the same time, the flow-optimised conical shape ensures low-turbulence flow with a low resistance coefficient.
Compared to conventional check valves or wafer check valves, the axial check valve offers significantly lower pressure loss and quiet, surge-free operation.
Materials and technical design of the RD100
The axial check valve RD100 is constructed in the standard version with the following materials:
- Body: EN-GJL-250 (GG25)
- Disc / guide: EN-GJS-400-15 (GGG40)
- Shaft: AISI 304L (1.4307)
- Spring: AISI 302 (1.4310)
- Seal: EPDM
- Temperature range: −10 °C to +80 °C
- Operating pressure: max. 16 bar
Available nominal sizes: DN50, DN65, DN80, DN100, DN125, DN150, DN200, DN250, DN300, DN350, DN400 and DN500. Flange connection according to PN10, PN16, PN25 and ANSI 150 – face-to-face dimension according to DIN EN 558.
Optional material combinations
For more demanding operating conditions, the RD100 is also available in alternative material combinations:
- Body made of GGG40 or Duplex for higher mechanical strength and corrosion resistance
- Spring made of Inconel for increased temperature and chemical resistance
- Seal made of Viton (FKM) for aggressive media and higher temperatures
The right material selection depends on the medium, temperature and pressure range. Fergo advises on selecting the optimal configuration.
Applications for axial check valves and nozzle check valves
Axial check valves are suitable wherever fast, surge-free closing and low pressure loss are critical. Typical applications for the RD100:
- Water supply and water treatment
- Pumping stations and pressure boosting systems
- HVAC and refrigeration technology
- Power plants and energy generation
- Process and chemical plants
- Industrial cooling circuits
Especially in high-pressure pump systems, nozzle check valves offer a longer service life and better dynamic performance than conventional swing or ball check valves. All versions are available for online purchase directly from Fergo.
Installation position and notes
The axial check valve RD100 can be installed in various mounting positions:
- Horizontal – standard installation
- Vertical – flow from bottom to top
- Inclined – depending on pipe routing
For vertical or inclined installation, the integrated spring supports reliable closing even against gravity. For clean media, an upstream strainer is additionally recommended to keep foreign particles out of the system and increase the service life of the valve.
