Implementation of a titanium strain gauge pressure transducer for CTD applications
Additional Document Info
The installation and operational characteristics of a titanium element strain gauge pressure sensor in conductivity-temperature-depth (CTD) instruments is described. The behavior of the sensor is examined in both steady state and transient conditions, the latter consisting of thermal shocks achieved in laboratory plunge tests. The titanium pressure sensor has superior linearity and reduced hysteresis as compared with strain gauges which utilize a stainless steel element. However, significant transient pressure errors are noted for certain gauge installations. A model of the pressure sensor’s transient is developed from heat transfer theory, which is solved for an idealization of the Mark III CTD configuration. This, in turn, motivates a numerical procedure for reducing the thermally-induced static and transient pressure error in the titanium strain gauge pressure sensor data, and an installation procedure that thermally isolates the gauge. Residual pressure error in calibrated data from the titanium strain gauge is an acceptably small fraction of a decibar.