Pressure gauges – pressure measurement

One of the fundamental parameters that define the thermodynamic state of a body is pressure. Its measurement is a component of nearly all measurements encountered in engineering practice. The instrument used to measure pressure is a manometer. Based on the reference pressure and the indicated pressure, pressure-measuring instruments are classified as absolute—indicating absolute pressure, i.e., relative to a vacuum—differential—indicating the pressure difference—manometers—indicating pressure relative to ambient pressure, vacuum gauges—which show relative pressure, but lower than ambient pressure, and manovacuum gauges—which indicate relative pressure both higher and lower than ambient pressure. Pressure gauges are classified as hydrostatic, spring-loaded, bell-type, electric, piston, and canister gauges.

What types of pressure gauges are used today? What do pressure gauges look like?

In practice, electronic pressure gauges are increasingly used. Their design is typically based on simple analog instrument constructions but also includes appropriate sensors, a processor, and a display. Electronic pressure gauges, like all devices of this type, are less precise than analog ones, but they allow for real-time adjustments. This makes them more practical. The simplest possible design is a liquid manometer, known as a U-tube. It consists of a tube with two open ends, calibrated arms, and is partially filled with liquid. This type works very well for measuring gas pressure. Spring-loaded pressure gauges are closed-end designs in which the pressure reading is determined by changes in the potential energy of the spring caused by pressure changes. Diaphragm gauges are more complex. They are typically used to measure small changes or to operate in systems where changes are significant.

Design and Function

Due to their different designs, each pressure gauge operates slightly differently. However, in each case, the measurement involves a force or the displacement caused by that force. This means that none of them directly measures pressure. Consequently, pressure gauges are not used indiscriminately—slightly different types of these measuring devices are employed for specific applications. It is also worth noting the professional solutions offered by reputable brands, such as Enerpac pressure gauges, which are widely used in industry and ensure high measurement precision.