Pressure gages are instruments that are designed to measure the pressure of a gas or liquid. Pressure gauges monitor and indicate the internal pressure of vessels or systems, especially those having dynamic working characteristics that require constant monitoring.
Related Categories
Pressure gages, more commonly known as pressure gauges, vary in style, size and material, depending on the application. Display types include graphical and video displays, digital readouts or analog meters and needles. Pressure gauges can also be equipped with electric contacts to turn on signal lights, sound alarms or operate a pump or valve. Pressure gages have a wide variety of industrial applications in which the pressure gauges are utilized. Specialty tanks, such as fire extinguishers and medical gas cylinders, use pressure gauges. Liquid filled gauges are utilized in nitrous systems on nitrous bottles or solenoids. Gauges made of stainless steel can be used in applications that have strict sanitary requirements and are capable of withstanding high pressure cleaning. Some high pressure gauges are specifically designed for use in high purity semiconductor gas and liquid applications with a range from vacuum to 10,000 PSI. Pressure gauges are essential for applications in which the accurate functioning of a vessel or system directly depends on the accuracy of the gauge reading, such as in pesticide sprayers.
There are two main kinds of pressure gauges: hydrostatic and aneroid. Hydrostatic gauges use the levels of liquid in a tube to determine pressure; examples include liquid column, piston type and manometers. Aneroid gauges have a membrane that flexes with the changing pressure. A standard pressure gauge is the Bourdon tube, a sensing element for measuring pressures of 15 PSI or more. Bourdon tubes are spirally wound or C-shaped, and when a pressure change occurs, the pressure gauges bend and produce a rotational movement, causing the gauge indicator to move. A diaphragm seal or gauge isolator can be used to prevent the Bourdon tube from coming into contact with the process material if the tube and material are not compatible. Gauges are used with multiple types of pressure including absolute, gauge, differential, sealed and vacuum pressure. Absolute pressure gauges are used to measure pressure that is referenced against a perfect vacuum, which would have a pressure of 0 PSI; it is the sum of the gauge pressure plus atmospheric pressure. Gauge pressure gauges measure pressure referenced against the pressure of the surrounding space (the ambient pressure). Differential pressure sensor gauges find the difference in pressure between two different systems or vessels. Sealed pressure sensors are used to gauge pressure as it relates to sea-level pressure. Vacuum pressure sensors measure pressure that is sub-atmospheric.
