Studies of the effects of thermal gradients on performance of pres¬sure trandducers indicate that:1. Flush diaphragm pressure transducers may show very large zero shifts due to thermal gradients even though they are compensated for changes in uniform temperatures. 2. For the thirteen units tested, the detailed design is as important as the principle used to convert diaphragm deflection to an electrical output signal, i.e., piezoelectric crystal, wire strain gages, bonded or not, differential transformer, etc. 3. Some transducers can operate in a thermal gradient with very little zero shift, but no simple way to predict this without testing is apparent at this time.nSince the transducer's zero shift in this test is the result of an imposed thermal gradient and is a function of the transducer design, a comparison of responses to thermal gradients reflects the comparison of transducer design features.nFor the transducers tested, although the rate of energy input and thermal flux density influenced the magnitude and the time to reach a given gradients, it is the temperature gradient itself that is responsible for the zero shift of the instrument and this should be considered when choosing a pressure transducer for field use.nThe wide range of response that was encountered in these tests emphasized the need for caution in interpreting the data furnished by pressure transducers when thermal gradients may be present. While these tests specifically aimed at conditions of temperature gradients in one particular direction, for gradients in other directions one can expect comparable effects and they should be investigated by the user.
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