What is a pressure gauge?
Pressure gauges are instruments for measuring and displaying the pressure of a medium. Pressure gauges are pressure measuring instruments with elastic pressure elements, which have been used millions of times in various industrial applications. Depending on the area of application of the pressure gauge, Bourdon tubes, diaphragm elements or capsule elements are used as pressure elements.
Which pressures do pressure gauges measure?
Pressure gauges measure gauge pressure, absolute pressure and differential pressure. Furthermore, not only can WIKA pressure gauges be used for measuring positive gauge pressure, but also for measuring negative gauge pressure.
How does a pressure gauge work?
Pressure gauges work differently depending on the type. In industrial measurement technology, two different types of pressure gauges are used - Bourdon tube pressure gauges and diaphragm pressure gauges. They have different functional principles and are therefore suitable for different applications. With Bourdon tube pressure gauges, the pressure is measured by a Bourdon tube transmitting pressure directly to the pointer. Inside the case there is a curved tube, into which the medium enters and causes the Bourdon tube to stretch. This stretching is transmitted to the movement via a link and a toothed segment and displayed on the dial as a corresponding deflection.
Bourdon tube pressure gauges can be used in a variety of ways and cover the majority of applications. However, when they reach their limits, diaphragm pressure gauges are used. In diaphragm pressure gauges, the pressure is transmitted via a wave-shaped diaphragm to a link. This then transfers the pressure to the movement.
What material should my pressure gauge be made of?
WIKA offers all common case forms. For standard applications, a plastic version with a copper-alloyed measuring system is sufficient for neutral media, such as compressed air, water or oil. For hydraulic applications, we recommend a robust chrome case with a glycerine filling that damps the measuring system against vibration and thus ensures good readability of the instrument. For measuring tasks in aggressive, not highly viscous and non-crystallising substances, even in aggressive environments, the pressure gauge variants made from stainless steel are suitable. The measuring system can also be coated with a special material such as PTFE, gold, Hastelloy and many others. This protects the instrument from aggressive media.
What is meant by the accuracy class of a pressure gauge?
On the dial of a pressure gauge we always find an indication of the accuracy class. The accuracy class of a pressure gauge defines the permissible deviation of the display in percent of the full scale value. For plastic cases, this is 4 % or 2.5 %, whereas for chrome steel or stainless steel instruments it is 1.6 % or 1.0 %. For test gauges, the accuracy class is 0.6 %, 0.25 % or even 0.1 %, depending on the display range used. What does this mean in practice? With a measuring range of 0 to 100 bar and an accuracy class of 1.0 %, the permissible deviation is 1 bar over the entire measuring range.