Bourdon tube pressure gauge
For special applications and even very high pressures, Bourdon tube pressure gauges are very popular in process, process and industrial engineering. The functioning of these measuring instruments is based on specially shaped measuring elements in usually helical, circular or spiral wound coil springs. The tube is closed on one side and connected on the open side. When pressurized, the thus shaped spring tends to expand. This movement is then converted to a displayable size via a special mechanism and displayed on a measuring scale.
Such Rohrfesern be made depending on the application of different materials. Depending on the medium to be measured (gaseous, liquid, etc.) and the composition of the medium (water, air, oils or acids, etc.), a suitably resistant material must be selected. The manufacturers like to use brass, copper or copper / nickel alloys. But there are also stainless steel and unalloyed steel used. For measurements in the vacuum range, quartz glass is also used as a particularly resistant material.
Applications and measuring ranges
Bourdon tube pressure gauges are often used for different measurements with different media. These include, for example, gas pressure measurements via gas pressure thermometers and use in switchgear. Depending on the pressurization, different types of Bourdon tube are used here. At pressures of 0.5 bar to 60 bar, a circular winding of the tube spring is preferred. In pressure ranges from 50 bar up to 1000 bar, the design of the worm spring is used. For extremely high pressures up to 4000 bar, the design of the worm spring is preferred.
Regardless of the suitable design of the Bourdon tube, the individual measuring ranges can still be adapted and extended very precisely. For this one simply varies the material used (for example copper or brass) and additionally the wall thickness of the tubes used. With this combination very accurate measuring ranges and sensitivities can be generated. But not only overpressure can be measured. Especially in the vacuum measuring range of up to 10-6 bar, special tube springs made of quartz glass are used. A particularly fine and sensitive mechanism then uses the material deformation for the actual pressure display via a pointer instrument.