The desirable features of piezoelectric sensors include their rugged construction, small size, high speed, and self-generated signal. The maximum range of such sensors is 5,000 or 10,000 psir. The output of such dynamic pressure sensors is often expressed in "relative" pressure units (such as psir instead of psig), thereby referencing the measurement to the initial condition of the crystal. Some of these rugged sensors can detect pressure events having "rise times" on the order of a millionth of a second, and are described in more detail later in this chapter. These sensors cannot detect static pressures, but are used to measure rapidly changing pressures resulting from blasts, explosions, pressure pulsations (in rocket motors, engines, compressors) or other sources of shock or vibration. The resulting electric signal can be measured as an indication of the pressure which was applied to the crystal. This deformation results in a flow of electric charge (which lasts for a period of a few seconds). When pressure is applied to a crystal, it is elastically deformed. This characteristic makes these sensors unsuitable for the measurement of static forces or pressures but useful for dynamic measurements. The fundamental difference between these crystal sensors and static-force devices such as strain gauges is that the electric signal generated by the crystal decays rapidly. When pressure, force or acceleration is applied to a quartz crystal, a charge is developed across the crystal that is proportional to the force applied (Figure 3-8). Depending on which phenomenon is used, the crystal sensor can be called electrostatic, piezoresistive, or resonant. Piezoelectric presssure sensors can further be classified according to whether the crystal's electrostatic charge, its resistivity, or its resonant frequency electrostatic charge is measured. Finally, the charge signal needs to be converted by a charge amplifier to a voltage which can then be read.In addition, the optimized diaphragm ensures accurate dynamic pressure measurements, even when the diaphragm is simultaneously exposed to a high thermal shock.Pressure sensor What is a pressure sensor? The compressed crystal produces a charge which is proportional to the pressure. The pressure to be measured acts on the sensor’s diaphragm and compresses the PiezoStar crystal. This PiezoStar crystal gives the sensor a far higher sensitivity than an equivalently sized pressure sensor based on synthetic quartz, which results in a lower noise level and so enables lower pressure to be measured more accurately.
#Piezo electric pressure sensor series#
At the core of the all-welded, hermetically sealed 601C series there is a high performance PiezoStar crystal grown by Kistler.
By contrast, piezoresistive pressure sensors are the right choice when measuring static pressure curves.
Another unique characteristic of piezoelectric pressure sensors is their ability to measure small pressure fluctuations that are superimposed on top of high static pressures with exceptional resolution. Due to their high natural frequencies, piezoelectric pressure sensors can be used for a variety of applications where dynamic pressures need to be measured.
0 kommentar(er)
