This section provides an overview for pressure gauges as well as their applications and principles. Also, please take a look at the list of 9 pressure gauge manufacturers and their company rankings.
Table of Contents
A pressure gauge is a device that measures the pressure of a fluid, such as gas or water.
Pressure is measured mainly by measuring the amount by which the elastic body inside the pressure gauge is deformed by the pressure. Various principles have been developed for measuring the amount of deformation, including the Bourdon tube, diaphragm, and bellows types.
Since there are different types of pressure, such as constant pressure, fluctuating pressure, and pulsating pressure, and there are absolute pressure, gauge pressure, and differential pressure depending on how the zero point is taken, it is necessary to select an appropriate pressure gauge by paying attention to the type of pressure to be measured and the pressure gauge's display method of output by the pressure gauge.
Incidentally, a pressure gauge that measures positive gauge pressure is called a pressure gauge, while one that measures negative gauge pressure is called a vacuum gauge.
Pressure gauges are used in equipment under pressure in factories, plant pipes, and residences. Pressure gauges should be selected appropriately according to the environment in which they are to be operated and the gaps in which they are to be used.
The following are examples of pressure gauges applications:
Pressure gauges basically measure pressure by reading the amount of deformation of an elastic body called a pressure-sensitive element. There are three types of pressure gauges: the Bourdon tube type, diaphragm type, and bellows type, depending on the type of pressure-sensing element, and the principle of each is explained below.
When pressure is applied to a metal pipe called a Bourdon tube, the Bourdon tube is displaced according to the pressure. The Bourdon tube pressure gauges measure the pressure by measuring the amount of displacement. The Bourdon tube pressure gauges can measure pressure without the need for external energy, such as electricity. Bourdon tube pressure gauges can be further classified into general-purpose, general, compact, sealed, and glycerin-injected types. The Bourdon tube type is widely used, but due to its small tube diameter, it cannot be used as it is when containing highly viscous fluids or solids.
Diaphragm type pressure gauges measure pressure by converting pressure into an electrical signal through a diaphragm using an element whose resistance value changes according to pressure. The characteristics such as long life and heat resistance vary depending on whether semiconductors, strain gauges, or thin films are used for the element. Since measurement is made using electrical signals, high-precision pressure measurement is possible. Diaphragm type is also suitable for corrosive or highly viscous fluids.
The bellows type pressure gauges measures pressure by converting the amount of displacement of a bellows-like cylinder with external folds under pressure into the amount of pressure. Because of its high sensitivity to pressure, the bellows tube type is suitable for measuring relatively low pressures.
Pressure gauges are attached to the piping through which the fluid whose pressure is to be measured flows. For analog gauges, the needle position is read straight from the front of the scale, as with other needle-type analog measuring instruments. In the case of digital gauges and pressure gauges, the indicated value is read directly.
Pressure gauges are connected directly to piping or other equipment. This means that there are some points to keep in mind when handling pressure gauges. If pressure gauges has malfunction, for example, unintentional removal of the gauge may result in fluid leakage or injury due to fluid leakage. The pressure in the piping must be reduced during removal, etc. In addition, fluid may remain inside the piping or pressure gauges after removal, or a small amount of that fluid may leak out when it is removed. Depending on the fluid being measured, care may be required in handling these.
In many cases, piping is branched to install pressure gauges, or branch pipes are installed for measurement. When designing or manufacturing new equipment or machinery that includes piping that handles such fluids, it is advisable to install a branch pipe for the pressure gauges in advance (if it will not be used immediately, just block it off) to minimize the work required when stopping the equipment or machinery later and connecting the pressure gauges.
A variety of pressure gauges are commercially available, depending on the intended use. Some selection methods are listed below.
*Including some distributors, etc.
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