Absolute Pressure Sensing and Its Applications
Pressure is a physical quantity that is measured by a wide array of devices. There are various methods to measure pressure, and each may provide a different reading for constant pressure in a given area. Differential and gauge pressure readings play critical roles in monitoring flow, leaks, and extreme pressure deviations in a closed system, but absolute pressure sensing has an even broader range of vital applications. In this blog, we will define absolute pressure sensing, how it is accomplished, as well as some of the numerous applications in which it is used.
Before understanding absolute pressure, it is first important to discuss atmospheric pressure. Atmospheric pressure is defined as the pressure exerted by our earth's atmosphere. Although a standard number has been established and accepted by the scientific community, this number varies based on several factors, including height, temperature, and the mass of air at the given height. Other forms of pressure measurement, such as gauge pressure, are affected by the variable atmospheric pressure. While this may not be an issue in many systems, some applications require a more accurate reading that is not influenced by changes in altitude, temperature, and other variables which affect atmospheric pressure.
Absolute pressure recording involves a sensor being in contact with an enclosed vacuum chamber. As a result, the device may use this pressure as a zero, meaning any changes in pressure are an accurate representation that is not affected by atmospheric pressure. The measurement end is then deformed or strained by the change in pressure. Since the material used for this portion of the device is selected based on its ability to change electrical characteristics based on strain, the magnitude of deformation may be measured using a piezoresistive device. Depending on the system in which the sensor will be integrated, there may be two or more resistors to help minimize noise and improve accuracy.
One of the primary uses for absolute pressure sensors is in meteorology, allowing users to quantify changes in barometric pressure caused by various weather patterns. Meteorological sensing devices commonly employ a highly-sensitive material such as single-crystal silicon in the circuit architecture, which also has a broad operating temperature range. To help further increase accuracy, such devices often include two or more sensors. This redundancy helps the system produce stable measurements to better predict local and regional high and low-pressure weather systems.
Absolute pressure sensors are also used to ensure that a vacuum remains intact, such as those in industrial packing machines. These machines utilize a vacuum pump to eliminate oxygen in an associated environment, such as medical products and perishable food items. Removing oxygen is critical to reducing the growth of aerobic bacteria, which might otherwise contaminate medical supplies or lead to accelerated food spoiling. Absolute pressure sensing is also the primary choice for research laboratories in both civil and military science since they consistently provide users with the most accurate results. If you are in need of absolute pressure sensing devices, look no further than Buy Aviation Parts.
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