Pressure Gauges

Pressure gauges are arguably the most known or commonly used measuring instrument onboard ships, offshore rigs or industrial plants. Available in a range as small as 0.5 millibars up to 7.000 bar, the pressure gauge comes in different scales, sizes and materials from other pressure gauge manufacturers. Our specialist helps you choose the needed gauge for your process.

A pressure gauge is an analogue or digital device that measures the pressure or vacuum within a fluid power system. One of the benefits of using pressure gauges is that they can be installed at any point within a process where the pressure needs to be measured.

You can prevent damage or downtime over pressure by monitoring the pressure within a system. Looking for more information on how a pressure gauge works? Please read our blog on what is a pressure gauge.

Which pressure gauge for which pressure type?

Depending on the type of pressure, you select your pressure gauge. There are three types of pressure you should know before choosing the correct gauge:

• Gauge pressure
• Absolute Pressure
• Differential pressure

Gauge pressure

Pressure gauges measure the difference between atmospheric and gauge pressure, also called ambient pressure. The atmospheric pressure depends on the weather and the altitude at which the pressure gauge is placed. At sea level, for instance, the average pressure is 1013.25 mbar. Since nearly all points in a production plant are equally exposed to the same air pressure, gauge pressure measurement usually is acceptable for industrial applications.

Absolute pressure

Absolute pressure is always about zero pressure obtained with a vacuum. Therefore, absolute pressure gauges should always be selected when the tiniest change in atmospheric pressure could affect the process. Applications for absolute pressure measurement are determining the vapour pressure for liquids, monitoring condensation pressures, and distillation. Other applications in which absolute pressure gauges are used are in the food industry.

Differential pressure

With differential pressure, we are talking about a type of pressure which – as the name suggests – specifies the difference between two pressures. Differential pressure gauges, therefore, have two process connections. They are used, for example, in the monitoring of filter and pump systems.

Types of gauges

The most common type of gauge is the analogue pressure gauge. These types of gauges show the pressure measurement on a dial. The needle is either moved due to the bourdon tube system, a diaphragm connection or capsule. Depending on the pressure gauge’s environment, it can either be filled or not. When the gauge is placed in a location between 0 and 100 °C it can be filled with glycerine for vibration protection.

Digital pressure gauges

In need for high-accuracy pressure measurement? Digital pressure gauges are ideal for low pressures due to resolution scales ranging from 0.001 to 0.01. In need of a digital pressure gauge? For more info, check out our assortment of digital pressure gauges.

Materials and sizes

The diameter of a pressure gauge is expressed in nominal size (NS). The nominal sizes of pressure gauges are: 40, 50, 63, 80, 100, 160 and 250 mm.

The housing of pressure gauges is, depending on the environment, made out of (ascending in resistance) plastic, steel, and stainless steel.

process connection
lower mounted (bottom connection) or back connection. Material variating from brass to steel.

Pressure Gauge Calibration

Pressure gauge calibration is an important and required factor that sometimes gets overlooked. When buying a pressure gauge, consider if it needs to be calibrated or certified before applying it to your process. The calibration and certification of pressure gauges are obligated when used, for instance, on vessels once every year.