Bypass valves
Product Stage Picture ByPass Ventil

Application areas

pump

heating

touchless faucet

Product range

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HomeProductsBypass valves

The HDS (hydrodynamic switch) valve is a dynamic bypass valve. By maintaining a defined differential pressure, it ensures constant flow conditions in special modules of boilers and touchless sensor faucets.

There are two application areas by way of example:
In water-driven mini-turbines of touchless faucets

By keeping the pressure loss at a constant level over a certain flow rate range, HDS valves ensure smooth turbine operation for power generation.

In hydraulic assemblies of boilers

HDS valves limit the delivery pressure of circulation pumps and ensure a minimum flow in the boiler circuit. They also avoid annoying flow noise caused by excessive differential pressure.

Quality featuresThe guide on both sides ensures high plunger stability in all positions, thereby preventing natural oscillations and noise problems.The plunger's geometric design provides for almost constant pressure loss over wide flow rate ranges while significantly reducing the level of inherent noise.Integral flushing openings protect the bypass valve from contamination of the guide area.HDS valves are designed to be robust and compact. They are made from standard POM material and are approved for use in drinking water applications in accordance with KTW and WRAS standards.Difference to › check valves (backflow preventers): In HDS valves, the plunger opens dynamically with the increased water pressure and keeps the pressure loss at a constant level across wide flow rate ranges. Reliable leakage-free backflow prevention is not required here, so HDS valves have no seal between plunger and housing. In contrast, a check valve reliably prevents backflow and keeps the pressure loss low.

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Function and installation

HDS bypass valves open as soon as the water pressure reaches a level defined by means of the force of the installed spring.

The more water flows, the wider the valve opens. The excess water is diverted past the main pipe with the device (pump or turbine), where the pressure and flow rate remain constant.

HDS bypass valves are installed in the flow direction.

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HDS closed

Constant flow at defined differential pressure

HDS partly open

Excess water passes through the HDS bypass valve

HDS fully open

Even more excess water passes through the HDS valve

Selection criteria

Please note that bypass valves are only available for our OEM / manufacturing customers. For more details, as well as information on worldwide approvals, please see the product listing. To refine your selection, please use the following points as filters.

Mounting bore: HDS bypass valves are available with bore diameters of 15 mm and 20 mm (0.59 and 0.79 inches) as well as springs with varying stiffness for specifying the pressure loss.Operating temperature: The maximum operating temperature is 65 °C (149° F), with peaks of 90 °C (194° F) within a period of up to 60 minutes.Differential pressure: For the different sizes, different levels of differential pressure are possible within the indicated range of 50 – 600 mbar. You can access PDFs with flow rate diagrams for the HDS 15 and the HDS 20 right below this section.

Do you need help choosing? You will find the relevant contact information towards the bottom of the page.

HDS 15 flow rate diagram  | pdf | 419.08KB
HDS 20 flow rate diagram  | pdf | 418.72KB
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16 Results

All downloads and properties
Bypass valve HDS 15-300
  • Part No. : 304903000
  • Bore diameter: 15.2 +/- 0.1 mm
  • Pressure drop: 300 mbar
Downloads and properties
Technical Product Information Download drawing ›  Download Specsheet
Bypass valve HDS 20-400
  • Part No. : 304906000
  • Bore diameter: 20.2 +/- 0.1 mm
  • Pressure drop: 400 mbar
Downloads and properties
Technical Product Information Download drawing ›  Download Specsheet
Bypass valve HDS 15-250
  • Part No. : 304907000
  • Bore diameter: 15.2 +/- 0.1 mm
  • Pressure drop: 250 mbar
Downloads and properties
Technical Product Information Download drawing ›  Download Specsheet
Bypass valve HDS 15-190
  • Part No. : 304909000
  • Bore diameter: 15.2 +/- 0.1 mm
  • Pressure drop: 190 mbar
Downloads and properties
Technical Product Information Download drawing ›  Download Specsheet
Bypass valve HDS 15-500
  • Part No. : 304911000
  • Bore diameter: 15.2 +/- 0.1 mm
  • Pressure drop: 500 mbar
Downloads and properties
Technical Product Information Download drawing ›  Download Specsheet
Bypass valve HDS 15-17
  • Part No. : 304912000
  • Bore diameter: 15.2 +/- 0.1 mm
  • Pressure drop: 17 mbar
Downloads and properties
Technical Product Information Download drawing ›  Download Specsheet
Bypass valve HDS 15-78
  • Part No. : 304913000
  • Bore diameter: 15.2 +/- 0.1 mm
  • Pressure drop: 78 mbar
Downloads and properties
Technical Product Information Download drawing ›  Download Specsheet
Bypass valve HDS 20-230
  • Part No. : 304905000
  • Bore diameter: 20.2 +/- 0.1 mm
  • Pressure drop: 230 mbar
Downloads and properties
Technical Product Information Download drawing ›  Download Specsheet
Bypass valve HDS 15-270
  • Part No. : 304908000
  • Bore diameter: 15.2 +/- 0.1 mm
  • Pressure drop: 400 mbar
Downloads and properties
Technical Product Information Download drawing ›  Download Specsheet
Bypass valve HDS 15-400
  • Part No. : 304904000
  • Bore diameter: 15.2 +/- 0.1 mm
  • Pressure drop: 400 mbar
Downloads and properties
Technical Product Information Download drawing ›  Download Specsheet
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No matches were found.For an improved search result, try changing your filter criteria or reset all filters. For further questions you can contact us.
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Please contact us for help finding the right bypass valve. Neoperl offers you solutions that are completely tailored to your requirements. Our qualified staff will be happy to assist you with any questions you may have.

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OEM / manufacturers
  • oem_inquiry@neoperl.com
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