Pressure gauges are a group of devices that measure and display the liquid or gas pressure levels inside enclosed vessels or systems. The measurement of pressure to the safe and proper functioning of many products and systems, such as water heaters and other water-based systems, fire extinguishers, medical gas cylinders, and many oil-based and gas-based systems.
To accommodate their many different applications, manufacturers make many different types of pressure gauges. Some are designed to measure specific substances or conditions. Examples of these include: water pressure gauges, air pressure gauges, oil pressure gauges, temperature gauges, gas pressure gauges, fuel pressure gauges, differential pressure gauges, and vacuum pressure gauges. Some of the uses of these gauges are more obvious than others. Water pressure gauges, of course, monitor the pressure of any water-based system.
Quite commonly, they are found attached to tanks, where they monitor the pressure of the water within. Air pressure gauges, also as their name suggests, measure pneumatic pressure in air-operated equipment. In the same way, oil pressure gauges measure the pressure of oil circulating in a lubricating system. Next, temperature gauges measure the temperature changes of any number of substances, including all of the former substances. Their applications range from scientific research to at-home temperature tracking.
Gas pressure gauges, as one might expect, measure and display gas pressure. They are especially prevalent in factories and manufacturing facilities, where they keep track of the flow rate of both high and low pressure natural gas and propane-based systems. Fuel pressure gauges also check gas pressure levels, but they do so in the context of automobiles; they measure and display the fuel supply, or amount of gas, left in a vehicle tank.
Differential pressure gauges are a bit different than the other gauges; instead of measuring pressure as a whole, they measure the difference in pressure between two points of contained liquid or gas. They are popular for filtration applications. Finally, vacuum pressure gauges measure and display the pressure within vessels or systems that are immersed in a sub-atmospheric or vacuum environment. Vacuum environments, after which vacuum pressure gauges are named, are used to create cold temperatures. Read More…
Other specialized gauges include seal gauges, absolute pressure valves, high pressure valves and low pressure valves. Seal gauges are designed with the addition of a diaphragm seal isolator; they are made specifically to stop and avoid potential leaks. Most of their applications are found in the process, pharmaceutical, chemical, petrochemical, and sanitation industries. Absolute pressure valves are used to measure pressure without the participation of barometric pressure variation; they are designed to monitor liquid vapor pressures and condensation pressures.
Pressure gauges may be designed to specifically measure substances flowing at either exceptionally high velocities or exceptionally low velocities. These are known as high pressure gauges and low pressure gauges, respectively. High pressure gauges are important to manufacturing and industrial applications, particularly those related to high pressure hydraulic technology, like hydrodemolition, hydroblasting pumps, and water cutting machines. Low pressure gauges are extremely accurate and sensitive, generally measuring pressures between ten and fifteen PSI. They are especially important to applications that take place in environments with frequent pressure fluctuation.
Two major groups of pressure gauges are analog gauges and digital pressure gauges. The difference between the two is in how they display information, which are in analog and digital form, respectively. Analog displays use needles that change where they’re pointing on the meter’s clock-like face, as the pressure changes.
This method of display was popular for many years, and is still used, but has now largely been replaced by digital displays, which are usually easier to read and more accurate. Digital pressure gauges, which typically run on batteries, are usually attached to an additional measuring device, which measures pressure and feeds the results back to the gauge, which then displays a numerical reading.
To enhance their performance, pressure gauges are frequently used in conjunction with complementary instruments, like sensors, switches, transmitters, and pressure transducers. With the addition of these devices, gauges increase in accuracy and precision, displaying more specific readings with smaller margins of error. They may also be equipped with electric contacts that sound alarms, turn on signal lights or control a valve or pump.
In addition, pressure gauges may be fabricated with a number of materials, depending on the demands of the application. For example, those gauges that will be exposed to harsh substances or chemicals must be corrosion-resistant, and will therefore most likely be made of stainless steel. Typical areas in which gauges are exposed to substances like these include the chemical, petrochemical, refining, power, and pharmaceutical processing industries.
For pressure gauges that will encounter only non-corrosive fluids or gases, on the other hand, a brass or bronze construction will probably be adequate. Regardless of their material makeup, pressure gauges are standard and custom designed to fit into any number of tight spaces or sufficiently span an uncommonly large tank.