Diaphragm valves

Diaphragm-seat valves with solenoid actuator, are used to shut off pressurised pipelines.

The sealing element is a circular, beaded, rubber diaphragm with a special shape. The diaphragm is clamped between the valve cover and the fitting, the flexibility of which allows the lifting movement.

We distinguish between 2 types of diaphragm valves:

  • servo-controlled diaphragm valves: (see function video Type 40) The OPEN/CLOSED stroke movement is effected solely by the existing pressure difference.
  • Force-controlled diaphragm valves: (see function video type 43) The stroke movement is ...
  1. directly by the solenoid force, if no pressure difference exists between inlet and outlet,
  2. supported by any pressure difference that may be present.

Features Diaphragm valves:

The complete valve is surrounded by the medium inside. This means that when specifying the valve, attention must be paid to suitable materials, both diaphragm quality and metallic materials. The direction of flow for diaphragm valves is fixed. The valve closes under pressure in the direction of the arrow, supported by the spring force. Pressure against the direction of the arrow and the valve opens. This characteristic is also referred to as reverse flow open. Diaphragm valves are available in nominal seat width from 13 mm to 50 mm in the form of threaded and flanged valves. Diaphragm valves are simple in design, maintenance-free and suitable for high switching cycles.

The choice of material combinations, both in diaphragm quality and body material, means that a wide range of different operating media can be controlled. The operating medium can assume the aggregate state gaseous, liquid or vapour at temperatures between -30°C and +140°C.

Diaphragm valves are normally closed (NC valve) as standard. Further options:

  • normally open (NO valve)
  • ATEX
  • Limit switch for detecting the end position OPEN or CLOSED
  • oil- and grease-free
  • Emergency manual override
  • Floodable IP68

Combinations of these are also possible. All options can be easily and efficiently determined using the ValveScout tool from Buschjost Magnetventile GmbH & Co. KG can be determined easily and efficiently.

Technical data and versions:

  • Electric solenoid actuators: 7 to 100 watts
  • Protection classes: IP65 - IP68
  • Duty cycle: 100%
  • Connection types: G-thread DIN EN 228, NPT or flange connection PN16/40, ANSI, groove/spring
  • Nominal sizes: DN13(15) to DN50
  • Operating pressure: max. 20 bar
  • Body materials: brass, stainless steel, grey cast iron, cast steel, nodular cast iron
  • Diaphragm materials: NBR, EPDM, FKM

Series, solenoid valve/diaphragm/servo-controlled

  • 28
  • 40
  • 3/124

Series, solenoid valve/diaphragm/forced pilot operated

  • 27
  • 43