Mechanical pressure gauges have been the mainstay of process instrumentation for a wide variety of industries. This simple, inexpensive device has multiple applications and allows users to monitor and control environments with relative speed and ease.

While the fundamental design remains more or less the same, technological improvements have made these gauges more accurate and easier to read over the years. Plus, instead of outdated clipboard rounds, electronic gauges can transfer information directly to a central location.

Let’s take a quick look at some design adaptations and accessories that have been developed over the years.


This device is a device used to snub or suppress sudden spikes in pressure. This mechanism allows the gauge to better protect against overpressure. This device is added to the gauge’s inlet and often slows down response, guarding the pressure gauge.

Seal or Isolator

The seal prevents process fluid from leaking into the mechanism. A flush diaphragm allows pressure ports to be sealed using an added stainless-steel seal. In this case, the transmission fluid transmits pressure to the internal sensor diaphragm through the external diaphragm. Isolators are used in situations with high temperatures, so the gauge needs to be protected or when products are hazardous.


To effectively measure the pressure of a condensable vapor, the siphon acts as a thermal barrier and traps condensate. The vapor puts pressure on the condensate slug inside the siphon. As a result, the siphon fills up with fluid and prevents the device from coming in contact with live steam temperature.

Blowout cases and safety cases

In high-risk environments, blowout cases are designed to break in a certain way that directs the release of fluid in one direction. This is to prevent people near the pressure gauge from coming in contact with the exposed process fluid.

Internal Dampening Systems

Internal dampening systems prevent gauge fluctuation and minimize wear on internal parts. This system is usually found in standpipe gauges that are used in harsh operating conditions and are often subject to vigorous vibrations and extreme temperatures.

Contact Instruments is a renowned manufacturer of drilling rig instrumentation equipment for oil and gas clients all over the US and Canada. Our popular products include Type F standpipe pressure gauges, electronic gauges, clipper weight indicators, overmolded custom cables, and drilling mud pumps.

For more information, call 780-955-8998 or browse our selection of products today.