Types of Pressure Gauges – Working Principles, Uses and Applications
Pressure measurement is an important part of almost every industrial process. Whether a factory operates pumps, compressors, boilers, pipelines or hydraulic equipment, monitoring pressure helps operators understand how the system is performing.
A pressure gauge is an instrument used to measure the pressure of a liquid or gas. It provides a visible reading so that operators can monitor operating conditions, identify unusual pressure changes and take action when required.
However, not every pressure gauge works in the same way. Different industries require different measuring mechanisms depending on pressure range, accuracy, temperature, fluid properties and installation conditions.
Understanding the types of pressure gauges helps engineers, maintenance teams and purchasing professionals select the correct instrument for their applications.
In this guide, we will explain the different types of pressure gauges, how they work, where they are used and what you should check before purchasing one.
CBT Flow Solutions Pvt. Ltd. supplies industrial pressure gauges from Baumer and Dwyer for various process applications. You can explore the complete pressure gauge range to review available products.
What Is a Pressure Gauge?
A pressure gauge is a mechanical or electronic instrument used to measure the pressure of a gas or liquid inside a system.
It is commonly installed on pipelines, pumps, compressors, boilers, pressure vessels, tanks and industrial machinery.
For example, consider a water pump supplying water to an industrial pipeline. The operator needs to know whether the pump is maintaining the required pressure.
A pressure gauge installed at the appropriate point provides a reading that helps monitor the system.
Most traditional pressure gauges display the measurement using a dial and pointer. Digital pressure gauges display the reading on an electronic screen.
Pressure gauges are available in different designs, pressure ranges, dial sizes and materials.
How Does a Pressure Gauge Work?
The working principle depends on the type of pressure gauge.
In a traditional mechanical gauge, pressure acts on a sensing element inside the instrument. This element moves or changes shape in response to the applied pressure.
The movement is transferred through a mechanical linkage to a pointer, which moves across the graduated dial.
The pointer indicates the pressure value.
In a digital pressure gauge, a pressure sensor converts the applied pressure into an electrical signal. The instrument processes this signal and displays the measured value digitally.
The sensing mechanism, material and measuring range determine which applications a particular gauge can handle.
10 Different Types of Pressure Gauges
Pressure gauges are classified according to their sensing mechanism, construction and intended application.
The following are commonly used types in industrial plants and process systems.
1. Bourdon Tube Pressure Gauge
A Bourdon tube pressure gauge is one of the most widely used mechanical pressure gauges in industrial applications.
It contains a curved metallic tube with an oval-shaped cross-section. One end of the tube is connected to the pressure inlet, while the other end is sealed and connected to a mechanical linkage.
When pressure enters the tube, its cross-section tends to become more circular, causing the curved tube to straighten slightly.
This movement is transferred to a pointer through a mechanical mechanism. The pointer then indicates the pressure on the dial.
Applications:
- Industrial pipelines.
- Water pumps.
- Air compressors.
- Hydraulic systems.
- Chemical processing.
- Oil and gas installations.
- General manufacturing equipment.
Bourdon tube gauges are available in different pressure ranges, dial sizes and materials.
CBT supplies SS Case Brass Bourdon Type Pressure Gauges and other Bourdon-type process gauges.
2. Capsule Pressure Gauge
A capsule pressure gauge is designed primarily for measuring low pressures.
Its sensing element consists of two thin, corrugated diaphragms joined together to form a sealed capsule.
When pressure enters the capsule, it expands or contracts. This movement is transferred to the pointer mechanism and displayed on the dial.
Because of its sensitive construction, a capsule gauge can measure relatively small pressure changes.
Applications:
- Low-pressure air systems.
- Ventilation systems.
- Pharmaceutical facilities.
- Cleanroom monitoring.
- Gas measurement.
- Laboratory equipment.
- Low-pressure process applications.
CBT lists Stainless Steel Capsule Gauges in different dial sizes and configurations.
The published product range includes low-pressure and draft-measurement options.
3. Diaphragm Pressure Gauge
A diaphragm pressure gauge uses a flexible membrane called a diaphragm as its sensing element.
When pressure is applied, the diaphragm deflects. The resulting movement is transferred to a mechanical indicator or another suitable measuring mechanism.
Diaphragm gauges are useful for applications where the sensing mechanism needs to be separated from the measuring mechanism or where specific process conditions make conventional Bourdon gauges unsuitable.
Depending on the design, diaphragm gauges can be used with corrosive, viscous or contaminated media.
Applications:
- Chemical industries.
- Pharmaceutical equipment.
- Water treatment plants.
- Food processing.
- Low-pressure measurement.
- Industrial process systems.
The diaphragm material and process connection must be compatible with the medium.
CBT lists SS Low/High Pressure Diaphragm Type Pressure Gauges for different industrial pressure-measurement requirements.
4. Differential Pressure Gauge
A differential pressure gauge measures the difference between pressure at two points rather than measuring pressure at only one point.
It typically has two connections: a high-pressure side and a low-pressure side.
The instrument compares the pressure at these two connections and displays the difference.
For example, a filter may have a certain pressure on its inlet side and a lower pressure on its outlet side. As dirt accumulates inside the filter, the pressure difference may increase.
A differential pressure gauge helps operators identify this condition.
Applications:
- Air filtration systems.
- HVAC installations.
- Cleanrooms.
- Water treatment plants.
- Hydraulic systems.
- Heat exchangers.
- Industrial filter monitoring.
CBT supplies Dwyer differential pressure instruments, including the Series 2000 Magnehelic Differential Pressure Gauge.
Its range also includes diaphragm-type differential pressure gauges and SS piston-type differential pressure gauges.
5. Digital Pressure Gauge
A digital pressure gauge measures pressure using an electronic sensing element and displays the result on a digital screen.
Unlike traditional mechanical gauges, it does not rely on a pointer and dial to show the reading.
The sensor converts the applied pressure into an electrical signal. The instrument processes this signal and displays the pressure in the selected unit, depending on the model.
Some digital gauges also provide additional functions such as unit selection, peak-pressure recording, zero adjustment and electrical output.
Applications:
- Industrial testing.
- Hydraulic equipment.
- Laboratory systems.
- Calibration work.
- Machine monitoring.
- Compressed-air systems.
CBT lists Dwyer digital instruments, including the Series DPG Digital Pressure Gauge.
The required measurement range, accuracy, power supply and environmental protection should be checked before selecting a digital model.
6. Glycerine-Filled Pressure Gauge
A glycerine-filled pressure gauge is designed to reduce the effect of vibration and pointer movement.
The gauge case contains glycerine or another specified filling liquid. This liquid helps dampen vibration and mechanical movement of the pointer.
This makes the reading easier to observe in installations where pumps, compressors or other machinery create continuous vibration.
It can also help reduce wear on some internal moving components.
Applications:
- Water pumps.
- Compressors.
- Hydraulic machinery.
- Industrial processing equipment.
- Vibrating pipelines.
- Mechanical equipment.
One important distinction is that a glycerine-filled gauge is not a separate sensing mechanism. It is generally a filled-case variation of an underlying pressure gauge, often a Bourdon tube design.
The filling liquid, temperature limits and material compatibility should be checked for the application.
7. Electric Contact Pressure Gauge
An electric contact pressure gauge combines pressure indication with electrical switching contacts.
It displays the pressure through a pointer while also allowing an electrical contact to operate when the pointer reaches a selected set point.
This can be used to trigger an alarm or send a control signal to compatible equipment.
For example, if pressure increases beyond a selected limit, the contact mechanism may activate an alarm or control circuit.
Applications:
- Pumps and compressors.
- Hydraulic systems.
- Industrial presses.
- Chemical processing.
- Automatic machinery.
- Pressure alarm systems.
CBT lists S.S Electric Contact Type Pressure Gauges with single or double contact options and stainless-steel construction.
Check the switching rating, contact arrangement and electrical protection before connecting the gauge to a control system.
8. Test Pressure Gauge
A test pressure gauge is used where accurate pressure measurement is important, particularly during equipment testing and calibration activities.
These instruments are generally designed with higher accuracy than ordinary utility gauges, depending on the selected model.
They may be used as reference instruments when checking the performance of other pressure gauges or pressure-measuring equipment.
Applications:
- Pressure gauge calibration.
- Testing laboratories.
- Industrial maintenance.
- Hydraulic pressure testing.
- Equipment inspection.
- Quality-control departments.
CBT lists S.S Test Pressure Gauges for relevant testing and measurement applications.
Always check the gauge’s specified accuracy class, calibration status and measurement range before using it as a reference instrument.
9. Sanitary Pressure Gauge
A sanitary pressure gauge is designed for applications where hygienic process connections and cleaning requirements are important.
These gauges may use stainless-steel construction and specialised process connections that allow them to be installed in suitable sanitary piping systems.
Depending on the design, a diaphragm or seal arrangement may help isolate the measuring mechanism from the process medium.
Applications:
- Food and beverage processing.
- Pharmaceutical manufacturing.
- Dairy plants.
- Biotechnology.
- Hygienic liquid processing.
CBT lists SS Sanitary Pressure Gauges with TRC-Clover Ends.
Before selection, check the process connection, wetted materials, surface finish, cleaning method and any required hygienic certifications.
10. Ammonia Pressure Gauge
An ammonia pressure gauge is specially selected for pressure measurement in refrigeration and other systems that handle ammonia.
The sensing element, process connection and wetted materials must be compatible with ammonia service and the operating pressure and temperature.
These gauges are commonly considered for ammonia refrigeration equipment and other compatible industrial installations.
Applications:
- Industrial refrigeration.
- Cold storage facilities.
- Fertilizer plants.
- Chemical processing.
- Petrochemical applications.
- Refrigeration machinery.
CBT lists an Ammonia Pressure Gauge with AISI 316L stainless-steel sensing-element construction and an AISI 304 stainless-steel case, with optional material configurations.
Always confirm compatibility with the actual ammonia service and manufacturer specifications.
Pressure Gauge Types: Quick Comparison
| Pressure Gauge Type | Main Working Principle | Common Application |
|---|---|---|
| Bourdon tube | Curved tube deformation | General industrial pressure |
| Capsule | Capsule expansion or contraction | Low-pressure gas measurement |
| Diaphragm | Flexible membrane deflection | Selected corrosive and process applications |
| Differential | Compares two pressure points | Filters and HVAC |
| Digital | Electronic pressure sensor | Testing and digital monitoring |
| Glycerine-filled | Damped mechanical indication | Vibrating machinery |
| Electric contact | Mechanical indication with electrical contacts | Alarms and control systems |
| Test gauge | High-accuracy pressure measurement | Calibration and testing |
| Sanitary gauge | Hygienic-compatible pressure measurement | Food and pharmaceutical processes |
| Ammonia gauge | Pressure measurement with suitable ammonia-compatible construction | Refrigeration and ammonia systems |
Some entries describe the measuring mechanism, while others describe the construction or application. This distinction is important when comparing products.
What Are the Different Pressure Measurement Units?
Pressure gauges display readings in different units depending on the application and instrument specification.
Common pressure units include:
Bar: Commonly used in industrial pressure measurement.
PSI: Pounds per square inch, frequently used in hydraulic, pneumatic and equipment specifications.
MPa: Megapascal, used in engineering and industrial pressure applications.
kg/cm²: A pressure unit still found on many industrial specifications and older equipment.
kPa: Kilopascal, commonly used in low- and medium-pressure measurement.
mmWC: Millimetres of water column, commonly used for low differential-pressure applications.
Always check the unit displayed on the gauge before interpreting or recording its reading.
How to Select the Right Pressure Gauge
Choosing the right pressure gauge depends on several technical factors.
1. Pressure Range
Select a gauge that covers the normal operating pressure and expected maximum pressure.
As a general selection guideline, normal operating pressure should usually fall between approximately 25% and 75% of the gauge’s full-scale range, ideally around 50–60%.
For example, if normal operating pressure is 10 bar, a 0–16 bar gauge may be a suitable starting point for evaluation.
However, also consider pressure surges, pulsation and maximum allowable pressure. Always check the manufacturer’s recommendations and applicable system requirements.
2. Accuracy Class
Accuracy class indicates the permitted measurement error as a percentage of the gauge’s full-scale range.
For example, a gauge with an accuracy class of ±1.6% has a different measurement tolerance from one rated at ±0.5%.
Choose the accuracy according to the measurement and control requirements.
3. Dial Size
Common industrial dial sizes include 63 mm, 100 mm and 160 mm.
A larger dial can improve readability, particularly when the gauge is installed at a distance.
4. Case and Wetted Materials
Choose materials according to the fluid, environment and installation conditions.
Common options include brass, aluminium, AISI 304 stainless steel and AISI 316 stainless steel.
The material of every wetted component is important, not just the external case.
5. Process Connection
Check the required connection size and standard.
Common options include 1/4-inch BSP, 1/2-inch BSP and NPT connections, depending on the model.
Also confirm whether bottom entry, back entry or another mounting arrangement is required.
6. Temperature
Confirm the process-fluid temperature and surrounding ambient temperature.
High temperatures can affect the sensing element, seals and measurement performance. A suitable diaphragm seal or another protective arrangement may be needed in certain applications.
7. Vibration and Pulsation
For vibrating installations such as pumps and compressors, consider a suitable liquid-filled gauge or another manufacturer-approved damping arrangement.
8. Special Application Requirements
Chemical compatibility, hygienic connections, differential measurement and electrical switching may require specialised gauges.
The final selection should always follow the operating conditions and product datasheet.
Applications of Pressure Gauges in Different Industries
Pressure gauges are used throughout industrial infrastructure.
Oil and Gas: Monitoring pressure in pipelines, compressors, separation equipment and process systems.
Chemical Industry: Measuring pressure in reactors, process lines, storage equipment and chemical-handling systems.
Pharmaceutical Industry: Monitoring compatible process equipment and utility systems where the measuring instrument meets the required hygienic and material requirements.
Water Treatment Plants: Measuring water pressure in pumps, filters, treatment equipment and distribution pipelines.
Power Plants: Monitoring pressure in boilers, steam systems, pumps and auxiliary equipment.
HVAC Systems: Differential pressure gauges help monitor filters, air handling systems and room pressure conditions.
Food and Beverage: Suitable pressure gauges monitor process equipment, tanks and hygienic utility systems.
Pressure Gauge Supplier in Mumbai – CBT Flow Solutions
CBT Flow Solutions Pvt. Ltd. is an authorised channel partner and supplier of industrial pressure gauges from Baumer and Dwyer.
Established in 1966 as C.B. Trading Corporation, the company supplies pressure-measurement instruments to process industries across Mumbai and other parts of India.
Its pressure gauge portfolio includes:
- Bourdon tube pressure gauges.
- Stainless-steel pressure gauges.
- Capsule pressure gauges.
- Differential pressure gauges.
- Diaphragm-type pressure gauges.
- Electric contact pressure gauges.
- Sanitary pressure gauges.
- Test gauges.
- Digital pressure gauges.
- Specialised ammonia pressure gauges.
The listed product range includes model-specific pressure ranges from 0–1 bar to 0–1000 bar, dial sizes and different case and wetted-material options.
CBT also supplies Dwyer Magnehelic differential pressure gauges for applications such as filter monitoring, cleanroom pressure measurement and HVAC systems.
For product specifications and enquiries, visit the CBT Pressure Gauge Supplier in Mumbai page.
Frequently Asked Questions
What are the main types of pressure gauges?
The main types include Bourdon tube, capsule, diaphragm, differential and digital pressure gauges. Specialised versions include electric contact, sanitary, test and ammonia gauges.
Which pressure gauge is commonly used in industries?
Bourdon tube pressure gauges are widely used for general industrial pressure measurement. The correct type still depends on pressure range, fluid compatibility, temperature and accuracy requirements.
Which pressure gauge is suitable for low-pressure measurement?
Capsule gauges and suitable diaphragm gauges are commonly used for low-pressure applications. The exact choice depends on the required measurement range and medium.
What is the difference between a Bourdon tube and a diaphragm pressure gauge?
A Bourdon tube gauge uses the deformation of a curved metallic tube to measure pressure. A diaphragm gauge uses the deflection of a flexible membrane. Their suitability depends on pressure, medium and process conditions.
What is a differential pressure gauge used for?
It measures the pressure difference between two points. Common applications include filter monitoring, HVAC systems, cleanrooms and water treatment equipment.
Why are glycerine-filled pressure gauges used?
Glycerine filling helps reduce pointer vibration and improve reading stability in installations exposed to mechanical vibration and pulsation.
Which pressure gauge is suitable for pharmaceutical applications?
Suitable capsule, diaphragm or sanitary pressure gauges may be considered depending on the process. Material compatibility, hygienic design, connection type and documentation must be verified.
How do I choose the correct pressure gauge range?
Identify the normal and maximum operating pressure, then select a suitable full-scale range. As a general guideline, normal pressure should fall around 50–60% of full scale, while allowing for pressure surges and operating conditions.
Which brands of pressure gauges does CBT Flow Solutions supply?
CBT Flow Solutions is an authorised channel partner and supplier of Baumer and Dwyer pressure instruments. The range includes mechanical, differential and digital pressure measurement products.
Different types of pressure gauges are designed for different measurement requirements.
Bourdon tube gauges are commonly used for general industrial applications, capsule gauges are useful for low-pressure measurement, diaphragm gauges suit selected process conditions, and differential gauges compare pressure between two points.
Digital, electric-contact, sanitary and test gauges provide additional features for specific applications.
The correct pressure gauge should always be selected according to pressure range, accuracy, dial size, materials, process connection, temperature and operating environment.
Understanding these factors helps engineers and purchasing teams choose a suitable instrument and obtain reliable pressure readings.
Looking for Industrial Pressure Gauges?
CBT Flow Solutions Pvt. Ltd. supplies Baumer and Dwyer pressure gauges for industrial measurement applications.
Whether you require a Bourdon tube gauge, capsule gauge, differential pressure gauge, digital pressure gauge or specialised process gauge, our team can help you evaluate the right product.
Share your required pressure range, dial size, accuracy class, process medium, connection type and quantity to help identify a suitable gauge.
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