PM/(D)S

PM/(D)S

Pressure/Vacuum Relief Valve
Pilot-operated diaphragm valve

Función y Descripción

The PM/(D)S type pilot-controlled PROTEGO® diaphragm valve is a highly developed valve for pressure and vacuum relief. It is primarily used as a safety device for outbreathing in tanks, containers, and process engineering equipment and it also offers reliable protection from vacuum and overpessure. It prevents the intake of air and unacceptable product vapor loss up to the set point. The valve can also be used as inbreathing valve. The main valve is directly controlled when it is exposed to a vacuum; e.g., it functions as a weight-loaded diaphragm valve. This valve is highly suitable under atmospheric conditions and for use in cryogenic service.

The main valve is controlled by a pilot valve. The pilot valve is controlled by the tank pressure. The tank medium does not continuously flow through the pilot. The set pressure is adjusted at the pilot valve by a corrosion-resistant and low-temperatureresistant permanent magnet.

As the operating pressure increases, the closing force acting on the main valve also rises; e.g. the valve tightness increases to prevent leakage until the set pressure is reached. After the valve responds, it immediately opens completely without any significant increase in pressure (pop open characteristic), and the nominal volumetric flow is discharged through a fully open valve. If this level is exceeded, the pressure increase follows the flow performance curve (Δp/V̇ curve). Up to the set pressure, the tank pressure is maintained with a tightness that is far superior to the conventional standard due to the superior manufacturing technology. This feature is achieved by valve seats made of high-grade stainless steel with precisely ground valve pallets. After the excess pressure is discharged or the vacuum is compensated, the valve reseats and provides a tight seal.

Características especiales y ventajas

  • high degree of safety due to double pilot
  • controlled by corrosion-resistant, low-temperature-resistant permanent magnet
  • the tank medium does not continuously flow through the pilot valve
  • pop-open characteristic from a minimum pressure rise to full lift
  • extreme tightness and hence least possible product losses and reduced environmental pollution
  • set pressure is close to full lift pressure, which results in high level of design freedom and product savings
  • high flow capacity
  • the control diaphragm of the main valve is shielded from low temperatures - high-level durability
  • can be used in areas subject to an explosion hazard
  • designed for use at low temperatures
  • self draining
PM/(D)S
PM/(D)S

Modelo y especificación

The valve is equipped with either a control pilot valve or with one control and emergency pilot valve to ensure optimum operating safety in case of malfunctions or damage.
Two different designs are therefore available:

Basic design of pressure/vacuum relief valve with a control pilot valve

PM/S

Basic pressure/vacuum relief valve with a control pilot valve and additional emergency pilot valve

PM/DS

Basic design of pressure/vacuum relief valve with a control pilot valve

PM/S

Basic pressure/vacuum relief valve with a control pilot valve and additional emergency pilot valve

PM/DS

Additional special devices available upon request.

Settings

Pressure:

+10 mbar +300 mbar
+4 inch W.C. +120 inch W.C.

Vacuum:

-3.0 mbar -7 mbar
-1.2 inch W.C. -2.8 inch W.C.
Higher or lower settings upon request.
PM/(D)S

Diagrama de flujo volumétrico

Los diagramas de flujo volumétrico han sido determinados con un banco de pruebas de caudal calibrado y certifi - cado por TÜV. El flujo volumétrico V. en [m³/h] y el CFH se refi eren a las condiciones estándar de referencia de aire según ISO 6358 (20°C, 1bar). La conversión a otras densidades y temperaturas están referidas en el Vol. 1: “Fundamentos Técnicos”.

PM/(D)S
PM/(D)S