FAQ-Product
Yes, metal check valves can be delivered with the option of a leakage hole (for a surcharge). The leakage hole is used to allow a small amount of medium to escape without having to open the fitting.
Yes, but only the versions with spring, as there must be permanent contact through a mechanical connection between the housing and the flap disc (spring) in order to exclude static charges or discharges that pose a potential ignition hazard.
The valve disc of a check valve opens into the pipeline system and strikes the pipeline, so the maximum opening is limited by the pipeline system.
Our DR series dual plate check valves are used whenever high flow rates are implemented and very good cv values are required.
Check the swing check valve for damage before installation. Ensure the valve moves smoothly. Damaged parts may not be fitted. Ensure that only swing check valves are fitted, whose pressure class, chemical resistance, connection and dimensions correspond to the conditions of use. There must be a straight piece of pipe of at least 5x the nominal diameter before and after the swing check valve.
Direct assembly on the pump flange is not recommended. Pulsing flow conditions and pressure shocks in the pipe system should be avoided. If the flow is vertical, installation is permitted only if the valve can open upwards; the ring bolt must point upwards if the check valve is installed horizontally. The flow direction of the check valve must be observed (see arrow on the identification plate). During a subsequent pressure test, the seal of the connections must be checked.
No, unfortunately we do not have VDS or FM approval for our check valves.
The following data is required:
- Type
- Nominal diameter
- Nominal pressure
- Maximum working pressure
- Pressure in front of the valve
- Desired pressure loss
- Temperature
- Medium
- Density
- Operating volume flow
- Standard volume flow
- Flow direction
Dual plate check valves CANNOT be converted into metallic flaps by removing the seals. Various housings and flap discs are used here.
The same applies to our swing check valves.
For pulsating and uneven flow conditions, for quieter guidance of the flap disc.
Due to a turbulent flow it can come to fluttering / noise. In addition, increased forces/loads occur, which can lead to premature wear (especially at the top of the attachments of the flap disc).
This would have no effect on the seal, but of course due to the "non-recommendation" in the technical documentation, the warranty would no longer be valid in the event of damage.
Yes, the metallic sealing intermediate flange check valves use the same housing as the soft-sealing flaps, only the sealing groove is left free.
The pump creates flow vortices in the pipeline. These can result in unstable flap behaviour and fluctuating opening angles, which leads to increased wear on the check valve. In addition, a strong noise development can occur. Of course, this is very individual depending on the application. However, in order to protect the valve from turbulence, we recommend that a calming distance between the pump and the check valve of 5 x DN be observed.
The dual plate check valve series DR has reduced turbulence in comparison to the swing check valve series ZR, thanks to the more stable action of the valve.
Check valves with return springs are used to ensure stable behaviour of the valve, and to prevent the disc from flapping in the flow or reduce flapping – this reduces the mechanical load, in particular, on the valve shaft and valve holder. Turbulence is reduced because the behaviour of the valve is more stable. The return spring ensures faster and more secure closure. Check valves without springs are used with low opening pressures and lower pressure drops.
Dual plate check valves are available in lengths according to DIN EN 558-1 series 16 (DIN3202 / K3) or API 594.
Yes, they can also be used with sealing surface A DIN1092-1.
We can issue a material testing certificate 3.1 (for a charge) and/or plant acceptance certificate EN 10204-3.1 (for a charge) for our high-quality ZR series swing check valves. Please contact us to receive these certificates. In addition, you can always access all available certificates/permits for a product under Certificates.
- Swing check valves are maintenance-free
- Shorter installation area
- Lower opening pressures
- Suitable for use with vacuum pressure
- Multiple material / seal combinations possible
- Additional securing of “moving” parts like screws and spring holder by the flange
There for you
Special requests, spare parts or a quick support? Our staff will answer your questions and concerns immediately.
You can reach us from Monday to Friday at +497143 9666900 and any time at sales@nieruf.com
Quality
Our certified quality management according to DIN EN ISO 9001: 2015 is part of our DNA. With our test stands we can carry out pressure tests with up to 350 bar with air and water as well as leak tests according to DIN EN 122661.
This is NieRuf
Committed
Commitment engenders trust. We stand by our word and are convinced that as a result not only our customers but also everyone we work with can rely on us.
Motivated
We always strive to find the best solution for our customers. It is our goal and incentive to have completely satisfied customers.
Competently
Technical and commercial expertise form the basis for developing qualified solutions tailored precisely to the needs of our customers.
Flexible
We do not adhere to rigid guidelines but instead focus on the individual wishes and needs of our customers. They are more important to us than internal company processes.
Contact 
Resistance check 
Frequently asked questions 
Configurator 