Pressure gauges are instruments used to measure the pressure of liquids, vapors, solids, and gases. The pressure is defined by the force of the exerted fluid when at rest or on a unit area, such as pounds per square inch or newtons per square centimeter. Pressure is a scalar quantity and the SI unit of pressure is Pascal.
How to Measure Pressure?
Most gauges calculate the pressure relative to atmospheric pressure as the zero point. The pressure gauges operate in a vented environment with ambient atmospheric pressure and are measured by using sensors to gauge the input pressure into a system. The pressure difference between the device and the atmosphere is calculated by this formula: P=Pa+ρgh.
Types of Pressure Gauges
The three most common methods for measuring pressure are absolute, gauge, and differential. Absolute pressure refers to the pressure in a vacuum, whereas gauge and differential pressures are the ambient atmospheric pressure or pressure in an adjacent vessel.
- Absolute Pressure Gauge (have zero pressure with no variation and are ideally used to measure the natural fluctuations in atmospheric pressure)
- Differential Pressure Gauge (measures the pressure difference in two chambers separated by an element that moves back and forth based on the changes)
- Bourdon Tube Pressure Gauge
- Diaphragm Pressure Gauge
- Capsule Pressure Gauge
- Bellows Pressure Gauge
- Manometer Pressure Gauge
- Piezometer Pressure Gauge
What is a pressure gauge used for?
Pressure gauges are used for a wide range of applications in both process and industrial markets. Here are some of the common pressure gauge applications:
Industrial Market
- Hydraulics and pneumatics
- Specialized OEM equipment
- Material strength testing
- Weighing systems
- Torque measurement
- Calibration laboratories
- Turbines & compressors
- Cryogenics
- Waterjets and water blasters
- Ammonia and refrigeration
Process Market
- Refineries
- Offshore oil rigs
- Chemical and petrochemical plants
- Pulp and paper
- Natural gas transmission and LNG
- Water and wastewater
- Power generation
- Mining and metals
Medical and Life Sciences
- Food and beverage
- Autoclave
Choosing the Right Pressure Gauges
There are a lot of specifications and functions that go into choosing the right pressure gauges for a testing requirement. For example, one of the most important elements to consider is choosing a pressure gauge with an analog display or a digital display. Analog pressure gauges do not require a power supply; however, it is less accurate compared to digital one. Looking at other specifications can also help determine the right device for you.
Pressure Gauges Specifications
- Pressure range (psi)
- Digital / analog
- Fixed or portable
- Dry or liquid-filled
- Accuracy
- Overpressure
- Operating environment
- Temperature
- Weather protection
- Process connection