Performance Of Pressure Transducers Research Articles

Characterization of a newly developed diaphragmless shock tube for the primary dynamic calibration of pressure meters

In conventional shock tubes with a diaphragm, many effects related to the burst of the diaphragm can influence shock formation, thus preventing an ideal pressure step change, as predicted by the shock tube measurement model being generated. This paper presents a newly developed diaphragmless shock tube with a quick-acting pneumatic valve, which demonstrates several advantages over conventional shock tubes with a diaphragm. The tests of the developed diaphragmless shock tube were performed using nitrogen at the atmospheric initial driven pressure, and at initial driver gauge pressures from 1 MPa to 7 MPa. The results show that the construction of the developed shock tube effectively reduces the generation of secondary shock waves and mechanical vibrations, which are often generated during the operation of shock tubes, thereby increasing the uncertainty of the shock tube calibration method. The uncertainty analysis shows that the developed diphragmless shock tube can act as a primary time-varying pressure calibration standard, generating pressure steps with a magnitude calculable from its measurement model to characterize the dynamic performance of pressure transducers with a relative expanded uncertainty of less than 0.025.

Dynamic neural network calibration of quartz transducers

AbstractThe performance of quartz pressure transducers is often compromised when subjected to thermal transients. In this paper, a new method of calibrating quartz transducers in which a neural network is used to accomplish a dynamic calibration of a transducer pair for a range of temperatures and pressures will be described. When a quartz pressure transducer is exposed to an environmental temperature change, thermal stress is induced in the sensing element. This thermal stress causes erroneous pressure readings until thermal equilibrium is achieved within the transducer. In order to compensate the undesirable transient thermal effects on the pressure transducer performance, multiple past and future temperature‐and‐pressure sensor outputs are used as inputs to a calibrating neural network. This new method allows the time‐dependent qualities of the quartz‐oscillator transducer to be included in the calibration scheme. This method can be applied generally to other types of transducers that are subjected to transient environmental effects and is not limited to quartz‐oscillator transducers. A theoretical discussion of this technology is presented, followed by experimental results obtained by applying the method to quartz pressure transducer calibration. Copyright © 2002 John Wiley & Sons, Ltd.

Method of evaluating frequency characteristics of pressure transducers using newly developed dynamic pressure generator

A dynamic pressure generator using a rotating valve has been developed to evaluate the dynamic characteristics and performance of pressure transducers. The waveform of the generated dynamic pressure is square, and the amplitude and fundamental frequency can be varied. In this paper, the generator using a novel rotating valve and the method of evaluating the frequency characteristics of pressure transducers using the generator are described. With the amplitude of the dynamic pressure of 10 kPa and varying the fundamental frequency in 1-Hz increments between 10 and 50 Hz, we measured the generated dynamic pressure using two different pressure transducers, and to obtain the amplitude spectrum of the measured waveform using frequency analysis. Then, the magnitude of the harmonic components in the spectrum are shown as a function of frequency. From the simultaneous outputs of two transducers, the frequency characteristics of one transducer was compared with that of the other.

The Effect of Zero Offset Changes on Pressure Transducer Performance

The Effect of Zero Offset Changes on Pressure Transducer Performance

Laboratory evaluation of pressure transducer domes containing a diaphragm.

Pressure transducers are being used with increasing frequency in patient care. The recent availability of sterile transducer domes containing a diaphragm provides a means for reducing the risk of bacteremia when using these devices. The present studies measured the effect of diaphragm domes on the accuracy of pressure measurement. The sensitivity and frequency responses of 5 pressure transducers utilizing diaphragm and nondiaphragm domes were compared. The results indicate that the type of dome utilized and the method of dome application can significantly modify pressure transducer performance. The data are useful in providing optimal accuracy and reliability of pressure measurments when using a diaphragm dome, pressure transducer combination.

Environmental Influences on Pressure Transducer Performance

The ideal pressure transducer responds to an input of pressure and pressure alone and has a unique, and preferably simple transfer function. The real transducer of course does not achieve this and its accuracy is characterised by the amount by which it deviates from ideal under the effect of pressure, the primary influence, or secondary influences such as temperature. Hysteresis and creep are two of the most serious errors, which occur even under constant environmental conditions, but usually as a result of changing pressure. Non-linearity is not necessarily to be regarded as an error. The errors that occur when the transducer is subjected to changes in a secondary influence such as acceleration, humidity and temperature are generally more severe. It is the purpose of this paper to demonstrate these effects, which fall into three categories: quasi-static changes, transient reversible and irreversible, in descending order of tolerability. As an example, the effect of acceleration may fall into any one of these categories. An inversion of a transducer may cause a steady and entirely reversible change in the output; shaking the device may give rise to a transient output which disappears when the excitation is removed, whereas a sudden and severe shock may irreversibly derange the transducer. In practice, the most important environmental influence is temperature, and the effects are examined in some detail. Thermal errors in the first and last category are well understood and are usually fully covered in manufacturers' specifications, but the most serious errors, and those for which it is most difficult to allow, occur in the second category under conditions of changing temperature. A good understanding of these effects is essential for the design of transducers and their installations.