How does a pressure gauge work

The purpose of a pressure gauge is simple: a manometer is used to measure pressure. More specific: a pressure gauge controls whether the pressure in a certain medium maintains equal to the atmospheric pressure. If it maintains equal, the mechanism will remain in balance and no deformation takes place; therefor, nothing happens. In case of increasing pressure, the indicating needle in the display will start to move because the tube or diaphragm within the pressure gauge will change its form. The most commonly used manometer is the Bourdon pressure gauge, but in many situations, a diaphragm pressure gauge is more suitable.

Operation of a Bourdon gauge

The mechanism of a Bourdon gauge is based on a small metal tube, usually made of brass. It is a slightly flattened, hollow, C-shaped tube. It has one open, and one closed end. The medium to be measured enters the tube through the opening. When pressure is put on the inside of the tube, the flattening will become more rounded, straightening the C-shape accordingly. This movement is transferred and magnified through the closed end, causing a set of gears to move and rotate. That provokes the indicating needle in the display to start moving to the right. It will indicate the value of the pressure on a round scale. When pressure decreases, the tube will regain its original C-shape and the needle will move back to the left.

Operation of a diaphragm gauge

When the medium to be measured is corrosive, polluted, or viscous, a diaphragm gauge should be used. The diaphragm separates the medium of the operating mechanism within the manometer, preventing it from damage caused by the medium. The operating principle of this type of pressure gauge is similar to the Bourdon gauge: a certain part is pressurized, causing a deformation that moves a mechanism. In the case of a diaphragm pressure gauge, this pressure is applied to a thin, circle shaped, metal diaphragm, causing it to bend. Usually, the diaphragm is flat, although in some cases it is corrugated to guarantee the linearity of the bending. The diaphragm is clamped or welded between two flanges. From the bottom side, the medium touches the diaphragm, bending it. Just like in a Bourdon gauge, this movement is transformed in a rotating movement through a mechanism, casing the display needle to move over a scale.

Measuring pressure in a fluid or gas

Which pressure gauge you need, depends on several factors. One of them is the medium. For example, when you need to measure pressure in a corrosive medium, you need a stainless steel pressure gauge. When measuring dangerous media such as acids, oxygen, toxic or inflammable substances, a pressure gauge provided with additional safety measures is required. An example of a safety measure is a blow-out function at the back of the instrument. It prevents leaks or crack in the front of the instrument when it suffers high pressure, which could cause bystanders to get hurt.

Complete range of pressure gauges

EMVO Techniek has a wide range of manometers and thermometers. Besides from popular instruments, such as a digital pressure gauge, our wide stock also can provide you wit special measuring instruments. U can buy for example:

Use and installation of manometers

On our page Assembly and usage instructions, you can find more info on usage and installation of pressure gauges. For optimal functioning of your instrument, it is important that it is installed correctly. In our Unit converter, you can easily and quickly convert different units. Ideal to verify all regulations that the instrument is required to meet.


At EMVO Techniek you can find a pressure gauge for any professional application. Depending on big or small differential pressure, the medium and other circumstances, we can advise you about the manometer you need. Due to our specialism on pressure gauges, we stand out in both product knowledge and efficiency. Are you not sure which pressure gauge you need? Would you like more information regarding the operation of a pressure gauge before placing an order? Ask us any question by contacting us. You can reach us by phone and e-mail.

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