Piston valves
The sealing element is a metal piston or flat disc with an annular seat seal. The piston is guided in the valve cover by special piston guide bands and grooved rings. This type of valve is robust, suitable for high pressures and suitable for a wide range of applications thanks to the use of a wide variety of sealing materials. Due to the shape of the piston, the valves are usually higher than diaphragm valves. Piston valves are more sensitive to contamination than diaphragm valves due to the relatively large piston surface area.
We distinguish between 2 control types:
- Servo-controlled piston valves: The stroke movement OPEN/CLOSE is achieved solely by the existing pressure difference.
- Force-controlled piston valves: The stroke movement is,
- directly by the magnetic force if no pressure difference is present between input and output,
- supported by any existing pressure difference.
Characteristics of piston valves:
The entire interior, from the valve base to the solenoid armature, is surrounded by the operating medium. This means that suitable materials must be used when determining the valve. The flow direction for piston 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. We refer to this characteristic as reverse flow open. Piston valves are available in seat sizes from 13 mm to 250 mm in the form of threaded and flanged valves.
Due to the choice of material combinations, a large number of different operating media can be safely shut off. At temperatures between -200°C and +300°C, the operating medium can assume the aggregate state gaseous, liquid or vapour.
Piston valves are ** normally closed (NC valve)** as standard. Further options and possible combinations:
- de-energised open (NO valve)
- AtEx version
- Limit switch for detecting the OPEN and/or CLOSED end position
- oil and grease-free
- Emergency manual operation
- Cryogenic version
- Hot vapour version
- Underwater installation
All options can be easily and efficiently determined using the Ventilscout tool https://www.buschjostventile.de/en/valve_scout.
Advantages
- Choice of body 1.4305, 1.4571, brass
- Variety of seals PTFE, FKM, EPDM, PTFE, Peek
- Large selection of options
- Wide temperature range -200°C to +300°C
- Application range from vacuum to high pressure
- as solenoid valve and electro-pneumatic valve
Technical data and versions:
- Body materials: brass, stainless steel, grey cast iron, cast steel, ductile cast iron
- Sealing materials: PTFE, PEEK, special materials
- Electromagnetic actuators: 7 to 100 watts
- Protection classes: IP65 - IP68
- Duty cycle: 100%
- Connection type: G-thread DIN EN 228, NPT or flange connection PN16/40, ANSI, tongue/groove
- Nominal size: DN13(15) to DN150
- Operating pressure: 16 bar, 25 bar, 40 bar, 70 bar ... 450 bar