Trafag pressure transmitters are high-quality pressure measurement devices suited to most requirements in very many of the harshest application areas. Apart from mature amplifier electronics ─ in the very latest products, equipped with ASIC ─ the associated pressure sensor is also of focal importance. For this reason, Trafag develops and manufactures each and every sensor in-house and is therefore able to look back over longstanding design and field experience in this sector.
All Trafag`s pressure sensors are based on the Wheatstone (resistance) bridge. At a change in pressure (deformation of the membrane), the resistance alters proportionally. This results in a change in current at the bridge.
Trafag pressure transmitters function on the following principles:
By means of complex coating processes under high vacuum, a thin layer of film, only a few micrometers thick, is superimposed on a stainless steel membrane. The pressure sensor is then welded together with a pressure connection to form an assembly highly compatible with sample media.
A Wheatstone bridge is superimposed onto a ceramic membrane by means of a screen printing process (thick film), and then fired.
In the piezo-resistive process, pressure is transferred indirectly to the measurement membrane via a liquid, normally silicone oil. Due to the temperature dependence of this transfer liquid, the procedure is influenced by changes in temperature. Temperature-compensation is therefore essential.