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Why we need diaphragm seals for pressure gauges or transmitters?


In industries that involve operations and systems with fluid processing, pressure measurement is a critical activity. These fluids are not always non-reactive and hence can damage the material of the pressure sensing equipment (such as pressure gauge and pressure transmitters) through corrosion. This results in erroneous readings and malfunctioning of the sensor itself. In such processes of pressure measurement in controlled environments, diaphragm seals are widely used for shielding the pressure sensors from being affected by the process fluid.

What is diaphragm seal?

A diaphragm seal is a pliable membrane that covers the sensor and its adjacent path to prevent the process fluid from coming in contact with it. The pressure of the controlled system can be easily measured through this membrane while the fluid is held back. Usually, isolation diaphragm seals are made of elastomers and can be customized as per the requirements of the fluid it is dealing with.

diaphragm pressure gauge
To measure the pressure of the fluid accurately, the space created between the chemical seal and the sensor equipment is filled with an appropriate liquid. The pressure from the process fluid is transferred to this liquid, which in turn is read by the pressure sensor. The diaphragm seal is mounted with the help of open-flanged, threaded, sanitary or other similar connections. They are also referred to as gauge guards or chemical seals. For systems that operate in environments of high pressure, the diaphragms are made of materials like Hastelloy, Inconel, Monel, stainless steel or titanium. Needless to say, some materials are better suited for certain fluids than others.

What are the chemical seals used in food industry?

In the food and beverage or pharmaceutical industries, these seals are used in the sanitary processes to prevent contamination occurring due to process fluid accumulation in the system. If a buildup of let's say milk happens in a pressure port or gauge, the entire production batch gets compromised. Additionally, fluids like ultra-pure water can lose their extreme purity if they come in contact with the metal of the pressure sensor. Diaphragm seals are also used to take care of any minor pressure fluctuations in certain pneumatic systems.

Improvement for diaphragm selas

Diaphragm seals have few areas of improvement and the current designs are equipped to handle such concerns. The newest models are designed to eliminate maximum dead space, are self-cleaning in nature and enable the continuous fluid flow. Some of the seals used in high-pressure situations have anti-clogging capacities due to the absence of the formation of internal cavities when mounted. Temperature-control and improved performance sensitivity by predicting and diffusing high-stress regions are two features incorporated in multi-purpose sensors, All of these add-on features result in better longevity and effective performance while preventing corrosion.

Conclusion

There are many options of diaphragm seals available for your use in the market. To find something that suits your application, share your requirements along with any prior experience that you have about the process with a product specialist.