The most common types of pressure gauges are nothing more than these three types: Bourdon tube (Bourdon Tube, for general high pressure), diaphragm type (Diaphragm, for corrosive or viscous media), and diaphragm type (Capsule, for special measurement of micro-pressure gas).

Of course, if you divide by function, you will also encounter differential pressure gauge (commonly used in filtration systems), absolute pressure gauge and digital table.

The core of the selection actually depends on these three points: what is the medium (liquid/gas), what is the pressure range, and what is the environment (there is no vibration or extreme temperature). Let me take these types of watches apart to help you find out which one to choose. If you choose the right one, you can save a lot of money for downtime and maintenance, and it is safer.

Mechanical Pressure Gauges

A. Bourdon Tube Pressure Gauges

This is definitely the “main force” of the instrument community “. If you walk into a factory and point to a pressure gauge, it’s probably a Bourdon tube. Its internal structure is very simple, that is, it 1 a C- shaped or spiral metal tube. As soon as the pressure comes, the tube will be “blown straight”, thus driving the pointer.
Applicable scenarios: clean liquid, gas and steam. General manufacturing, heating, ventilation and air conditioning (HVAC) and hydraulic systems (up to 100,000 PSI).
The reason I recommend it: cheap, leather solid, and huge range coverage.
Pit Avoidance Guide: Never use a standard Bouldon tube to measure “dirty” things (like sludge, waste water, concrete) or high viscosity fluids. Once the medium enters the tube, dry or blocked, the watch is useless.

B. Diaphragm Pressure Gauges

Unlike the Bourdon tube, this watch uses a flexible diaphragm (diaphragm) to sense pressure. The medium pushes the diaphragm, and the diaphragm pushes the movement again.
Application scenarios: corrosive chemicals, viscous fluids, slurries, or occasions with extremely high hygiene requirements (food and pharmaceutical).
The reason I recommend: the medium can’t touch the internal gear mechanism at all. And you can plate the diaphragm with Teflon, gold or Hastelloy, specifically hard, strong acid and alkali.
The rule of thumb: If you’re in the food and beverage industry, this is pretty much your only safe option (usually with a hygienic chuck). Bouldon tube is easy to hide dirt and dirt to breed bacteria. There is no dead corner on the diaphragm surface, so washing is over.

C. Capsule Pressure Gauges

The diaphragm box is to weld two thin diaphragms together. It is extremely sensitive to small pressure changes.
Applicable scene: low pressure gas measurement. Such as furnace negative pressure, medical breathing equipment or leak testing.
The reason I recommend: the accuracy of the general pressure gauge is not good when it is less than 15 PSI. But in the range of 0-10 PSI (or millibar), the film box table is the king.
stern warning: absolutely can not be used to measure the liquid! The weight of the liquid itself (static pressure) can make the reading deviate and even crush the capsule. Remember, it belongs only to gas.

Specialized Function Types

Differential Pressure Gauges (DP Gauges)

The ordinary gauge measures the pressure at a certain point, while the DP gauge measures the “difference” between two points “.
Killer app: Filter monitoring.
Scenario simulation: You have a filter on the pipeline, how do you know if it is blocked? A differential pressure gauge is installed before and after the filter. The more dirty the filter element, the greater the pressure drop. When the pointer points to the red area, it reminds you that it is time to change the filter element.
Other uses: liquid level measurement of closed tanks, or flow measurement with orifice plates.

Liquid Filled vs. Dry Gauges

Characteristics

Feature	Dry Gauges	Liquid Filled (Glycerin/Silicone)
Cost	Lower	Higher (approx. 20-30% more)
Vibration	Needle shakes (hard to read)	Needle is stable
Lifespan	Shorter in harsh environments	Longer (internals lubricated)
Moisture	Lens may fog up	No fogging
Verdict	Use for stationary, low-vibration areas.	Essential for pumps, compressors, and high-vibration machinery.

Conclusion

Standard configuration for high vibration equipment such as static and vibration-free area pumps and compressors.

My suggestion: as long as your pipe has vibration, even if it is only a little bit, spend that extra 10 yuan to buy an oil filling meter. The damping effect of the liquid can protect the fine gear from being damaged. The replacement cost saved is in absolute value back to the fare.

How pressure gauge Work

Gauge pressure vs. Absolute Pressure (Gauge pressure vs. Absolute Pressure)

gauge pressure (PSIG): the vast majority of the table on the market is this. It measures pressure relative to atmospheric pressure. If the table shows 0, the pressure in the pipe is the same as the air outside. Imagine pumping a tire, that’s gauge pressure.
Absolute pressure (PSIA): This is the pressure relative to the absolute vacuum. Generally used in meteorological barometer or vacuum packaging machine.

Digital vs. Analog (Digital vs. Analog)

Analog (pointer type): Suitable for a quick glance (“Is the pointer still in the green area?”). You don’t need batteries, you can use them there.
Numbers: Can give you precise numbers (such as 105.4 PSI). It is suitable for data recording and automation integration, but it is troublesome to supply power.

FAQ on Pressure Gauge Selection

Q: Does the medium I measured have a great influence on the selection?

A: The medium is the most critical factor. According to my rule of thumb:
Clean water or gas: standard BURDON tube is enough, cheap and easy to use.
Corrosive, sludge or slurry: must be on the diaphragm table, otherwise the internal mechanism will be waste in a few days.
Low pressure gas: the diaphragm meter is the only option that can guarantee accuracy.

Q: Which kind of table is best in a large vibration environment like pump or compressor?

A: Where there is vibration or pressure pulsation, the oil filling gauge must be installed. Glycerin or silicone oil filler can dampen pointer jitter, so you can read accurately, and lubricate internal parts for a much longer life. Dry meter? Use it only in a static environment.

Q: When should I use a normal meter and when should I use a differential pressure (DP) meter?

A: Look at your purpose:
Monitor the overall pressure of the system: use ordinary pressure gauge.
Monitor the pressure drop before and after the filter, pump or valve: a differential pressure (DP) meter must be used. This is the best tool to judge whether the filter is blocked or not.

About the Author

I am a Senior Instrumentation Application Engineer with over 15 years of hands-on experience in the petrochemical and HVAC sectors. Throughout my career, I have focused on solving complex process control issues and diagnosing equipment failures directly in the field. I write these guides to bridge the gap between textbook theory and real-world application, helping you choose the exact right instrumentation to prevent costly system downtime.