A diaphragm seal separates a gauge from the process medium using a thin, flexible metal diaphragm. Such seals are used in industries as diverse as oil and gas and foods and beverages. They can be mounted onto a measuring instrument via a direct threaded connection or by means of a flexible capillary and probe device. For high temperatures, a cooling element can be fitted between the diaphragm seal and the instrument.

Most important from the user’s standpoint is to understand when diaphragm seals are necessary. Here are eight common uses for using gauges equipped with diaphragm seals.

1. When using corrosive media. Such substances are commonplace in the oil and gas and chemical industries, making this one of the most familiar uses for a diaphragm seal. Gauges equipped with diaphragm seals protect the pressure-measuring element from the corrosive media.
2. When using very hot media. Applications involving high temperatures are also a common application for diaphragm seals, which reduce the effects of heat on the instrument. Besides protecting the gauge from damage, the diaphragm seal eliminates the likelihood that high temperatures will result in inaccurate gauge readings.
3. When remote readings are necessary. In industrial settings, gauges must often be placed in hard-to-reach places, making it difficult or impossible to read them. Diaphragm seals can be installed in tandem with a capillary measurement probe, thus simplifying the installation and reading of gauges. Such lines can be up to 50 feet in length.
4. To avoid environmental hazards. Today’s industries must take care in the use of a plethora of toxic substances. Among these precautions, diaphragm seals prevent toxic or harmful media from escaping into the environment.
5. Health and hygiene. Industries such as food processing, beverage production, pharmaceuticals, medical labs and others have stringent requirements for sterility and cleanliness. Diaphragm seals remove dead space within the measuring instrument and its fittings which might otherwise harbor dangerous bacteria.
6. Sticky situations. Some industrial media can be viscous – “sticky” – or fibrous liquids that contain minute solid particles. These factors can lead to clogged instrumentation and can create dead spaces within a chamber, resulting in inaccurate readings. A diaphragm seal prevents these issues.
7. Keeping chambers clear. Some substances have a tendency to crystallize and polymerize. Diaphragm seals keep crystals and polymers away from the measurement chamber.

By keeping process media flowing properly, diaphragm seals reduce or eliminate the occurrence of production-line issues or breakdowns. And by ensuring higher gauge accuracy, they provide plant personnel with better information on their operations, thus alerting them to problems before it’s too late and ensuring both the safety and productivity of the entire operation and the people who run it.A diaphragm seal separates a gauge from the process medium using a thin, flexible metal diaphragm. Such seals are used in industries as diverse as oil and gas and foods and beverages. They can be mounted onto a measuring instrument via a direct threaded connection or by means of a flexible capillary and probe device. For high temperatures, a cooling element can be fitted between the diaphragm seal and the instrument.