The function of the check valve is to only allow the medium to flow in one direction and prevent the flow in the opposite direction. Under the pressure of fluid flowing in one direction, the valve diaphragm opens. When the fluid flows in the opposite direction, the fluid press the the valve diaphragm to act on the valve seat, thus cutting off the flow.
Rubber diaphragm is one of the key components in check valves. The performance of rubber diaphragms in these valves depends heavily on the material selection and specific technical requirements according to the requirement of the application. Here’s an overview of the commonly used materials and key requirements for rubber diaphragms in check valve applications.
Common Materials
EPDM Diaphragms:
EPDM provides excellent resistance to water, steam, making it ideal for water and gas applications, particularly in environments where heat and low temperatur (down to -50℃) stability are needed.
Recommended operating temperature range is -50℃~150℃
FKM Diaphragm:
FKM, also known as Viton®, is used for its superior heat and chemical resistance. It’s particularly effective in applications where the diaphragm may encounter with chemicals like, fuels, or elevated temperatures.
Recommended operating temperature range is -20℃~180℃.
We also have low-temperature-resistant FKM material with optimized the compression set performance at low temperatures.It could work under -35℃ with higher cost.
FVMQ Diaphragm:
Compare to FKM rubber, FVMQ has better performance in low temperature and chemical resistance. It can be used with harsh chemicals such as fuel, methanol.
Recommended operating temperature range is -50℃~180℃
PTFE EPDM Diaphragm:
The combination of PTFE and EPDM rubber creates a unique composite material that offers excellent chemical and temperature resistance, low-friction, and good sealing function.
The PTFE layer offers a low-friction surface, reducing wear and extending the lifespan of Diaphragm.
Recommended operating temperature range is -50℃~150℃
Challenge for the production of rubber Diaphragm
In addition to the above material selection, the manufacturing process of the rubber diaphragm is also crucial.
The thickness requirement of some products is very low, only 0.3mm thick. Such a small thickness needs to ensure that the product has no cracks.
The product has high dimensional accuracy requirements and cannot have warpage.
For more details, contact OBT Rubber Seal for customized Diaphragm solutions for your valve applications.
