The basic structure of sanitary diaphragm valve consists of valve body, diaphragm and actuator.
- Valve Body
Valve bodies typically include two or more ports that connect inlet and outlet flow. A diaphragm, made of elastomer or thermoplastic material, acts as a flexible barrier between the two ports. An actuator controls the movement of the diaphragm to open or close the valve.
The sealing principle of sanitary diaphragm valves is based on the deformation of the diaphragm, which creates a tight seal between the two ports. When the valve is closed, the actuator applies pressure to the diaphragm, forcing the diaphragm against the sealing surface of the valve body. This compression of the diaphragm creates a seal that prevents any fluid from passing through the valve.
- Valve Diaphragm
Diaphragm material plays a vital role in the sealing efficiency of the valve and its compatibility with different applications. Flexible diaphragms, such as EPDM (ethylene propylene diene monomer) or silicone, are typically used in applications involving low to moderate temperatures and non-corrosive fluids.
For more demanding applications, thermoplastic diaphragms made of materials such as polytetrafluoroethylene (PTFE) can be used due to their excellent chemical resistance and durability.
- Actuators can be manual, pneumatic, or electric
Their selection depends on factors such as the required control accuracy, the level of automation and the application environment. Pneumatic actuators, for example, can exert a high force on the diaphragm, ensuring a tight and reliable seal even under high pressure conditions.
The sealing principle of the sanitary diaphragm valve also enables it to be used in bi-directional flow applications. This means that the valve can be installed in piping in any direction, enabling it to meet a wide range of process requirements.
However, potential limitations of sanitary diaphragm valves must be considered. High-pressure applications may require larger, more robust actuators to ensure adequate sealing force.