Electromagnetic diaphragm valve is a special structure of direct acting or pilot operated solenoid valve. It uses electromagnetic force as a power source to open or close fluid channels by controlling the up and down movement of a diaphragm (a flexible film).
The core design feature is to use a flexible diaphragm to completely isolate the flow channel inside the valve body from the upper electromagnetic drive mechanism and valve chamber. This makes it particularly suitable for situations that require strict sealing, prevent cross contamination, or handle high viscosity, particle laden fluids.
Pilot operated electromagnetic diaphragm valve
Working Principle:
Closed state: In the power-off state, the pilot hole is closed, and fluid pressure enters the chamber above the diaphragm from the inlet channel. Due to the piston area being larger than the diaphragm area, the pressure acting above the diaphragm is greater than below, tightly pressing the diaphragm onto the valve seat and keeping the valve closed.
Open state: After the coil is powered on, the electromagnetic force opens the pilot hole, and the pressure medium above the diaphragm quickly releases pressure through the pilot hole. At this point, the fluid pressure at the inlet generates an upward force below the diaphragm, which is sufficient to overcome the residual pressure and spring force above, lift the diaphragm, and open the valve.
Features: Low power consumption, capable of producing larger diameters, but requires a certain fluid pressure difference (minimum pressure difference) to function properly.
4、 Main features and advantages
Excellent sealing performance: The flexibility of the diaphragm enables it to tightly adhere to the valve seat, achieving zero leakage sealing.
High cleanliness and isolation: The diaphragm completely isolates the fluid medium from all moving parts such as iron cores and springs. This means:
Pollution prevention: The fluid will not come into contact with the internal metal parts of the valve, making it very suitable for hygiene applications such as food, medicine, and biotechnology.
Corrosion resistance: The diaphragm material (such as PTFE) can be selected according to the fluid properties, and the valve body can also be made of corrosion-resistant materials, so that only key components need to be protected against corrosion, reducing costs.
No risk of internal and external leakage: avoids the possibility of medium leakage through the valve stem seal.
Ability to handle complex fluids: Able to easily handle high viscosity fluids, slurries, media containing particles or fibers, as the flow channels are unobstructed and there are no narrow gaps that may be blocked.
Easy maintenance: The valve cover can usually be easily opened, and the diaphragm can be inspected and replaced without removing the valve body from the pipeline.