Pressure gauges, alternatively spelled as pressure gages, are
instruments used to measure and display the pressure of a gas or liquid
inside a closed system or vessel. They are capable of working with
various liquids and gases.
There are many different kinds of pressure gauges, and they are applied in all kinds of contexts. Air pressure gauges measure pneumatic pressure in any air-operated equipment and can feature analogue or digital displays, as can most gauge varieties. Differential pressure gauges are instruments that measure the difference in pressure of a gas or liquid between two points. A water pressure gauge monitors the pressure of any water-based system and is commonly attached to tanks that require monitoring of the liquid within. Fuel pressure gauges are instruments that specify the pressure of the fuel supply to the intake manifold in a combustion engine vehicle. This display represents how much gas is left in the tank. An oil pressure gauge is a tool that measures the pressure of oil circulating in any lubricating system. Maintaining the correct amount of oil in a vehicle can increase its longevity; the same is true in machinery. A gas pressure gauge measures and displays the pressure of a gas. They are widely used by manufacturing plants or industrial companies where it is important to monitor any changes in pressure in order to control the rate of flow of gases such as propane or natural gas. They are used to measure very high pressures as well as low pressures. Vacuum gauges are instruments used to measure and display sub-atmospheric or vacuum pressures within a system or vessel. Vacuums are frequently used to create cold temperatures for certain processes. Temperature gauges take measurements in a variety of materials including air, oil and water and are used in simple home purposes as well as in scientific processes.
Pressure gauges monitor and indicate the internal pressure of vessels or systems, especially those having dynamic working characteristics that require constant monitoring. 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 gauges are utilized in a wide variety of industrial applications. 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; they feature pressure ranges from less than 15 PSI to as high as 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.
Differential pressure gauges are instruments that measure the difference in pressure of a gas or liquid between two points. This eliminates the need for an operator or computer system to watch two gauges and perform the math. It is fast and efficient to have the information immediately and constantly displayed in one location. Digital pressure gauges are attached to an instrument that measures the pressure of a gas or liquid and gives numerical readings. They display readings in digital, rather than analog, form. Digital readouts are typically easier to read and provide greater accuracy. They usually run on batteries and are available on most kinds of pressure gauges. High pressure gauges are instruments that measure and display the pressure of gases and liquids moving at high velocities. When the temperature rises or more gas and liquid is added to the container, the pressure increases even more. High pressure gauges are used for industrial and manufacturing applications, mainly for high pressure hydraulic technology including water cutting machines, hydro-blasting pumps and hydro-demolition. Low pressure gauges generally measure pressures of 10 to 15 PSI. Gauges designed for low pressure are extremely sensitive and accurate out of necessity; many processes depend on the correct pressure to function properly and safely. Gauges are used in environments where the pressure tends to fluctuate frequently and so requires constant monitoring.
Pressure gauges are often combined with other similar instruments such as pressure transducers, sensors, transmitters and switches. Gauges may be in the same location or contained in the same enclosure. Because of their widespread usage and critical performance, pressure gauges are continually being improved. As the boundaries of what science and innovation can accomplish continue to be expanded, the abilities of gauges must improve as well. Gauges are becoming more precise and accurate, able to display more specific readings with smaller margins of error. In analogue gauges, the dials themselves are more detailed and often have multiple sets of units displayed on the face. The materials being used are increasingly strong and durable, able to stand up to tough environments. Corrosion resistant units are made of stainless steel and are used where chemicals or harsh substances need to be looked after and monitored. Because of the wide use of pressure gauges, they are being manufactured in a variety of sizes to fit in tight spaces or on very large tanks. The technology inside the gauges has improved, too. For hydrostatic gauges, different liquids are being tested to determine which most accurately reflects pressure changes. Aneroid gauges use different membrane materials that are more sensitive than previous versions in order to detect even small pressure differences.
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Pressure Gauges Types
measure any pressure above zero pressure. It is impossible to create a perfect vacuum artificially, and no perfect vacuums exist on earth or anywhere in space. Absolute pressure gauges measure pressures on a scale that begins with zero, though a pressure of zero is impossible to achieve.
- measure the air pressure of pneumatic equipment.
- , also called "sea level gauges," are
the most commonly used gauge. Ambient gauges are preset to read zero
at standard atmospheric pressure (~14.7 psi).
- measure both pressure and vacuum.
- , also referred to as "general purpose gauges" or "equipment
gauges," are low-cost measuring instruments designed for applications
that do not have severe conditions. Commercial gauges may be ruggedly
constructed but are not typically economical to repair.
- provide the relative pressure between
two measurement points. An indication of differential pressure only
occurs when one pressure is higher or lower than the other.
- are industrial standard gauges, typically battery-powered,
which use a digital display rather than an analog dial display. Digital
readouts are typically easier to read and provide a greater accuracy
- are instruments that indicate the pressure of
the fuel supply to the intake manifold in a combustion engine.
- A gas pressure gauge is an instrument designed to measure and display the pressure of a gas.
- High pressure gauges are instruments that measure and display the pressure of gases and liquids moving at high velocities, up to 10,000 PSI, a very high pressure when compared to the atmospheric pressure of ~14.7 PSI.
- have heavy-duty sensing elements and case designs
and higher accuracy requirements than general purpose gauges. They are built
for extended life and are designed for use in harsh environments.
- can be filled with various fluids, such as silicone
oil, mineral oil and glycerin. The liquid fill provides protection
to internal components of the gauge in severe environments in which
the gauge may encounter excessive vibration and pulsation.
- Low pressure gauges are designed to accurately measure pressures less
than 15 PSI using a capsule sensing element.
- are instruments that measure
and display the pressure of the oil in an enclosure, particularly oil circulating in a lubricating
- are extremely sensitive and highly accurate
instruments that are used in applications that demand precision and
consistent results, such as instrument shops, gauge repair and calibration
shops and testing laboratories.
- Pressure gauges are instruments that are designed to measure the pressure of a gas or liquid. Pressure gages monitor and indicate the internal pressure and/or the vacuum of vessels or systems, especially those having dynamic working characteristics that require constant monitoring.
- are made from corrosion resistant material to meet the
demanding heavy-duty operating and construction requirements of the
chemical and petroleum industries. Process gauges are also designed
to fulfill the exacting accuracy and service life needs of a variety
of process applications.
- have a scale that is compressed at either one or both
of its ends.
- Temperature gauges are instruments that indicate the temperature of an item or substance being measured. The results may be displayed through an analog dial or digital readout.
- indicate negative atmospheric pressure or the degree
of rarefaction below atmospheric pressure.
- are designed to determine and monitor the pressure
of any system that uses water.
Pressure Gauges Terms
A thin walled elastic tube of metal that is flat and formed into a circular
shape, which tends to straighten in response to increases in pressure
and is fixed to a pressure recording or indicating device such as a gauge
- The part of the gauge that
works with the dial to indicate the pressure level
way of making a modification in indication with an adjustable needle
with the change being the same over the whole scale
- The insertion
of a plug in the wall of the gauge that vents when there is an element leak
to prohibit excess pressure build up in the case
- The highest pressure
a gauge can maintain with no apparent alteration in accuracy
- A periodic pressure swell
- The highest difference
from any two or more successive indications for identical working conditions
and applied pressure
- The apparatus that limits
the flow of fluid between the pressure element and the source of pressure
- The scale of this gauge
is compressed at either one or both ends
- The part that firmly fixes
the window to the case
- The point at which a vessel's capacity to contain pressurized material is exceeded
- The markings on the dial comprised
of gradations, related numbers and units of measure
- An apparatus for the reduction
of the effect of pressure variations and surges
- The major supporting
element of the pressure component assembly that the elastic component
- The alteration
of pressure indication that is caused by the difference of temperature
in the components from the temperature at which they were calibrated
- Any element of a gauge
that comes in direct contact with pressure media
- A clear component made of
glass or plastic closing the front of the case