Pressure Gauge Types and How They Work Engineers, technicians and buyers can choose an appropriate pressure gauge to measure the pressure of liquid or gas based on their knowledge of the types of pressure gauges. Bourdon tube, diaphragm, bellows, capsule, digital and differential gauges are common types of designs. Gauge, absolute or vacuum pressure can also be measured by instruments. Need help sourcing a pressure gauge? Send us your pressure range, process medium, connection, accuracy and operating conditions for specification-based sourcing assistance. Request a Quote Quick answer: A pressure gauge is used to measure the force from a gas or liquid against atmospheric pressure, against a vacuum or against another process pressure. The mechanisms in the main designs are mechanical or electronic devices that transform pressure into a readable sign. Main Pressure Gauge Types at a Glance The types of pressure gauges can be classified in two ways. Bourdon, diaphragm, bellows and capsule describe the sensing element. Gauge, absolute, differential and vacuum describe the pressure reference. Digital and analogue identify how the result is processed or displayed. Gauge design How it works Typical use Bourdon tube A curved tube deforms as internal pressure increases. General pneumatic, hydraulic and process duties Diaphragm A flexible membrane moves in response to pressure. Low pressure and challenging process media Bellows A flexible bellows expands or contracts. Sensitive low-pressure measurement Capsule Two joined diaphragms expand under pressure. Low-pressure gaseous media Digital An electronic sensor produces a numerical reading. Testing, maintenance and portable measurement Differential Two pressure inputs are compared. Filter monitoring, flow and tank level How Mechanical Pressure Gauges Work Bourdon Tube Gauge Bourdon tube pressure gauge has curved, flattened tube. If there is pressure on, the tube will attempt to straighten.Linkages convert this small movement into pointer rotation. Among common pressure gauge types, this design is widely used because it can serve many general industrial applications without electrical power. Examples of commercially available configurations include an Emerson ASCO 50 mm, 12 bar gauge and an Emerson ASCO 40 mm, 10 bar gauge . These links are provided as product examples only. Buyers should verify the full model specification and application compatibility. Diaphragm, Bellows and Capsule Gauges Diaphragm pressure gauge is a type of pressure gauge in which the deflection of a circular membrane is used to indicate the pressure. Depending on construction and materials it may be appropriate for low pressure or media that might cause a narrow pressure path to be blocked. The compatible diaphragm seal can also be used to isolate corrosive and viscous or crystallising media from the instrument. Bellows pressure gauge is a device that is accordion type.. A capsule pressure gauge uses two joined diaphragms and is commonly associated with sensitive, low-pressure gas measurement. These are important types of pressure gauges used in industry, but their usable range depends on the individual model. Digital and Differential Pressure Gauges A digital pressure gauge converts sensor output into a numerical reading. It may offer selectable units, minimum and maximum recording, or data output. In a digital vs analog pressure gauge comparison, digital equipment may provide easier reading and additional functions, but it is not automatically more accurate. Always compare the stated accuracy, resolution and calibration data. A differential pressure gauge measures the difference between two inputs. Common applications are: pressure drop across a filter and flow or vessel level measurement. This is not gauge pressure (which references against atmospheric pressure) or absolute (which references the theoretical perfect vacuum). Expert note: Sensing technology and pressure reference are separate specifications. A gauge can use a diaphragm sensing element while also measuring differential pressure. Examples of Industrial Gauge Configurations Industrial pressure gauges are used on compressors, pumps, hydraulic equipment, water systems, manufacturing machinery and process lines. Smaller pneumatic applications may use a Norgren 40 mm, 1 bar threaded gauge , while another system may require a Norgren 63 mm, 10 bar threaded gauge . You can explore the wider pressure gauges category or review related gauges and indicators for replacement, maintenance and project requirements. How to Choose Between Pressure Gauge Types Learning how to choose a pressure gauge type begins with the process specification. Avoid selecting a product from its dial range or price alone. Record the following details before comparing industrial pressure gauges: Pressure reference: Gauge, absolute, differential or vacuum. Range: Normal, minimum and maximum operating pressure. Medium: Gas, liquid, steam or aggressive chemical. Materials…