Bourdon Tube Pressure Gauge: Working, Applications & Advantages
Pressure measurement is one of the most fundamental parameters in industrial process control. From chemical processing plants to oil refineries, from pharmaceutical production lines to power generation facilities — pressure monitoring ensures safety, operational efficiency, and equipment longevity.
Among the various pressure measurement technologies available today, the Bourdon tube pressure gauge remains the most widely used mechanical pressure instrument in the world. Its simplicity, reliability, and cost-effectiveness have made it the backbone of industrial pressure measurement for more than 150 years.
In this comprehensive guide, we will explore:
- What is a Bourdon tube pressure gauge?
- Working principle explained step-by-step
- Construction and components
- Types of Bourdon tubes
- Applications across industries
- Advantages and limitations
- Accuracy classes and standards
- Selection guidelines
- Maintenance and calibration
- Why choosing a reliable manufacturer matters
If you’re looking to buy industrial pressure gauges or understand how they work before making a purchasing decision, this guide will help you make an informed choice.
Table of Contents
What is a Bourdon Tube Pressure Gauge?
A Bourdon tube pressure gauge is a mechanical device used to measure gauge pressure in gases and liquids. It operates based on the deformation of a curved metallic tube when pressure is applied internally.
The invention dates back to 1849 by French engineer Eugène Bourdon. Despite technological advancements in digital instrumentation, the Bourdon tube design remains highly relevant in modern industrial environments due to its durability and reliability.
Working Principle of a Bourdon Tube Pressure Gauge
The working principle of a Bourdon tube pressure gauge is based on the elastic deformation of a curved tube.
Step-by-Step Working Mechanism:
- Pressure Entry
- The process fluid (gas or liquid) enters the gauge through the pressure inlet (socket).
- Internal Pressure Applied
- The pressure travels into the curved Bourdon tube.
- Tube Tends to Straighten
- When pressure increases, the oval-shaped cross-section of the tube tends to become more circular.
- This causes the curved tube to slightly straighten.
- Tip Movement
- The free end (tip) of the tube moves outward due to deformation.
- Mechanical Linkage Transmission
- This movement is transmitted through a link and gear mechanism.
- Pointer Movement
- The gear converts linear motion into rotary motion.
- The pointer moves over a calibrated dial scale.
- Pressure Displayed
- The dial indicates the pressure value.
When pressure decreases, the tube returns to its original shape due to its elasticity.
This simple mechanical system allows accurate pressure indication without requiring electricity.
Construction and Main Components
A standard Bourdon tube pressure gauge consists of the following components:
1. Bourdon Tube
- Curved metallic tube (C-shaped, spiral, or helical)
- Made from materials like:
- Phosphor bronze
- Stainless steel
- Monel
- Inconel
2. Socket / Pressure Inlet
- Connects gauge to the process line
- Usually threaded (BSP/NPT)
3. Linkage Mechanism
- Connects tube tip to gear
- Transfers movement
4. Sector Gear & Pinion
- Converts linear motion into rotational motion
5. Pointer
- Indicates pressure on dial
6. Dial
- Calibrated scale (bar, psi, kg/cm², MPa)
7. Case & Window
- Protects internal mechanism
- Can be:
- Steel
- Stainless steel
- ABS
- Window: glass, acrylic, or safety glass
8. Optional Features
- Liquid filling (glycerin/silicone)
- Blow-out back
- Dampening mechanism
- Electrical contacts
Types of Bourdon Tubes
There are three main types based on design:
1. C-Type Bourdon Tube
- Most common design
- Suitable for medium pressure ranges
- Used in general industrial applications
2. Spiral Bourdon Tube
- More sensitive than C-type
- Used for low pressure measurement
3. Helical Bourdon Tube
- Used for high pressure ranges
- Offers greater displacement
Pressure Ranges Covered
Bourdon tube gauges can measure:
- Vacuum: -1 bar
- Low pressure: 0–1 bar
- Medium pressure: 0–100 bar
- High pressure: 0–1000 bar
- Very high pressure: up to 7000 bar (special designs)
This wide measurement capability makes them versatile for almost every industrial sector.
Applications of Bourdon Tube Pressure Gauges
Bourdon tube pressure gauges are used across multiple industries due to their robustness and ease of installation.
1. Oil & Gas Industry
- Pipeline pressure monitoring
- Compressor systems
- Storage tanks
- Hydraulic systems
- Refineries
2. Chemical Industry
- Reactor pressure measurement
- Acid handling systems
- Boiler pressure
- Distillation columns
3. Power Plants
- Steam pressure measurement
- Turbine systems
- Condensate lines
4. Pharmaceutical Industry
- Cleanroom applications
- Sterile processing
- Water systems
5. HVAC Systems
- Refrigeration pressure
- Air compressors
- Chillers
6. Marine Industry
- Engine room monitoring
- Hydraulic controls
- Ballast systems
7. Food & Beverage
- Pasteurization systems
- Steam pressure
- Process control
Advantages of Bourdon Tube Pressure Gauges
Despite the availability of digital transmitters and electronic sensors, Bourdon tube gauges offer several benefits.
1. Simple and Reliable Design
No electronic components, making them durable and long-lasting.
2. No Power Required
Works purely mechanically.
3. Cost-Effective
Lower initial investment compared to digital systems.
4. Wide Pressure Range
Suitable from vacuum to ultra-high pressures.
5. Easy Installation
Simple threaded connections.
6. Low Maintenance
Minimal servicing required.
7. Rugged Construction
Ideal for harsh industrial environments.
8. Quick Visual Indication
Operators can instantly see pressure levels.
Limitations
Although reliable, Bourdon tube gauges have some limitations:
- Not ideal for extremely low pressures (better suited to diaphragm gauges)
- Less suitable for highly pulsating pressures without dampening
- Mechanical wear over time
- Manual reading (not remote monitoring)
However, liquid-filled and damped versions solve many of these challenges.
Accuracy Classes and Standards
Accuracy is defined as the permissible error as a percentage of full-scale reading.
Common accuracy classes:
- Class 2.5
- Class 1.6
- Class 1.0
- Class 0.6
Example:
If a 100 bar gauge has Class 1.0 accuracy:
Allowable error = ±1 bar
Standards followed:
- EN 837
- ASME B40.100
- IS standards
For critical industrial applications, Class 1.0 or 0.6 is recommended.
Selection Guide: How to Choose the Right Bourdon Tube Pressure Gauge
Choosing the correct pressure gauge is crucial for performance and safety.
1. Pressure Range
Select a gauge where:
Operating pressure = 50–70% of full scale
2. Process Media
- Corrosive? → Stainless steel
- Non-corrosive? → Brass acceptable
3. Temperature
High temperature requires:
- Syphon
- Cooling element
4. Vibration
Use:
- Liquid-filled gauges
5. Accuracy Requirement
Critical processes → Class 1.0 or better
6. Mounting Type
- Bottom entry
- Back entry
- Panel mounting
7. Environmental Conditions
Outdoor → Stainless steel case preferred
Liquid-Filled Bourdon Gauges
Liquid-filled gauges (glycerin or silicone) offer:
- Vibration resistance
- Shock absorption
- Reduced pointer flutter
- Extended life
These are recommended for compressors and heavy machinery.
Calibration and Maintenance
Regular calibration ensures accurate readings.
Calibration Methods:
- Using dead-weight tester
- Comparison test pump
- Digital pressure calibrator
Calibration interval:
- Typically every 6–12 months
Maintenance Tips:
- Avoid overpressure
- Use proper mounting
- Protect from corrosion
- Inspect periodically
Safety Considerations
Pressure gauges must include safety features:
- Blow-out back
- Solid front case
- Overpressure protection
- Proper venting
Failure in high-pressure systems can be dangerous, making quality manufacturing essential.
Why Quality Manufacturing Matters
A poorly manufactured pressure gauge can lead to:
- Incorrect readings
- Process inefficiency
- Equipment damage
- Safety hazards
- Regulatory violations
Industries depend on precision instrumentation for operational integrity.
Why Choose a Trusted Manufacturer?
When selecting a Bourdon tube pressure gauge, always consider:
- Manufacturing standards
- Material quality
- Calibration facilities
- Testing procedures
- Industry experience
- Customization capability
Reliable manufacturers provide:
- In-house calibration
- Quality raw materials
- Compliance with global standards
- Custom designs
- Technical support
For industries across India and global markets, companies like Japsin Instrumentation deliver high-performance pressure gauges engineered for durability, safety, and accuracy.
Comparison: Bourdon Tube vs Other Pressure Gauges
| Type | Best For | Limitations |
|---|---|---|
| Bourdon Tube | Medium to high pressure | Not best for ultra-low pressure |
| Diaphragm | Low pressure | Limited high-pressure capability |
| Capsule | Very low pressure | Limited range |
| Digital | Remote monitoring | Requires power |
For most industrial applications, Bourdon tube remains the most practical solution.
Future of Bourdon Tube Pressure Gauges
Even in Industry 4.0 environments, mechanical gauges are not obsolete. Instead, they are integrated with:
- Pressure transmitters
- Alarm switches
- IoT sensors
- Remote monitoring systems
Hybrid systems combine mechanical reliability with digital intelligence.
Frequently Asked Questions (FAQs)
Q1: What is the lifespan of a Bourdon tube pressure gauge?
Typically 5–10 years depending on environment and usage.
Q2: Can it measure vacuum?
Yes, specially designed vacuum gauges are available.
Q3: Is liquid filling necessary?
Recommended for vibrating environments.
Q4: How often should it be calibrated?
Every 6–12 months or as per process requirement.
Q5: Can it handle corrosive fluids?
Yes, with stainless steel or special alloy materials.
Conclusion
The Bourdon tube pressure gauge continues to be a cornerstone of industrial pressure measurement. Its simple mechanical design, wide pressure range capability, cost-effectiveness, and proven reliability make it indispensable across industries.
From oil refineries to pharmaceutical plants, from HVAC systems to marine applications, Bourdon tube gauges ensure accurate and safe pressure monitoring.
When selecting a pressure gauge, never compromise on quality. Choose a trusted manufacturer that offers certified, durable, and precision-engineered instruments tailored to industrial demands.
If your organization is looking for high-quality industrial pressure gauges with reliable performance and competitive pricing, partnering with an experienced Indian manufacturer like Japsin ensures safety, accuracy, and long-term operational excellence.
Japsin Instrumentation – Since 1974
