WAM Products

VHS - Membrane Pressure Relief Valves

VHS - Membrane Pressure Relief Valves

Description and working principle

For some time tighter safety regulations in industrialized countries have ensured stricter enforcement of rules regarding the safeguarding of silos and bins against positive and negative pressure. There is no question that other countries will have to follow this example.

Pressure Relief Valves by WAM® are the last safety net when abnormal pressure conditions endanger the silo structure. This is why sudden excess or suction pressure inside the silo must be dealt with instantly. Even though ideally a Pressure Relief Valve should never have to go into action, it must be efficient and reliable if needed.

The counterweight-loaded VHS-type Pressure Relief Valve by WAM® has one decisive advantage compared to the other type made by WAM®, the VCP. Due to the moment of inertia of the helical springs on the VCP, pressure balance is re-established extremely quickly but not instantly. The VHS, on the other hand, does the job in real time. Through an interplay of pressure on different surface areas on both sides of a diaphragm fitted inside the valve housing, perfect pressure balance is achieved. In the event of excess pressure this interaction enables air from inside the silo to flow back into the atmosphere. In case of suction pressure the air penetrates from the atmosphere into the silo.

VHS Pressure Relief Valves are available as

  • Carbon steel version VHS2731B
  • 304 stainless steel version VHS2732B

These Valves are preset for a maximum negative pressure of - 0.005 bar (0.07 psi) and a maximum excess pressure of + 0.05 bar (0.72 psi).

Should the customer’s requirements be different, the Valves can be set at a maximum excess pressure ranging from + 0.02 bar (0.29 psi) to + 0.08 bar (1.16 psi).

Weight: 22 kg (49 lbs)

Advantages and innovative features

  • The working principle of the VHS Pressure Relief Valve itself is innovative. Its special double-acting diaphragm pervious to air sees to both excess and suction pressure relief.
  • The special properties of the diaphragm avoid blockage, as well as the formation of material crusts.
  • Maintenance and calibration, if necessary, are extemely easy.
  • Ideal for indoor installation and those applications where no exhaust dust in the environment is acceptable (valve is connected to exhaust duct)