Pressure Gauge with Isolation Valve and “O” Syphon

A pressure gauge with an isolation valve and “O” syphon is a standard assembly used in steam and high-temperature pressure systems. This setup protects the gauge from excessive heat while allowing safe maintenance and accurate pressure monitoring.

It is widely installed in boilers, steam lines, and industrial heating systems where direct exposure to hot steam may damage the pressure gauge.

Main Components and Their Functions

Pressure Gauge

The pressure gauge is the main instrument used to display system pressure in bar, psi, or other units. It provides operators with real-time pressure readings for safe and efficient operation.

Function:

• Monitors system pressure continuously

• Helps detect abnormal pressure conditions

• Ensures safe operation of equipment

Isolation Valve (Globe Valve)

The isolation valve is installed between the process line and the pressure gauge.

Function:

• Allows the operator to shut off pressure to the gauge

• Enables safe removal or replacement of the gauge

• Suitable for maintenance or calibration without shutting down the system

“O” Syphon (Pigtail Syphon)

The “O” syphon is a loop-shaped pipe installed between the process connection and the gauge.

Function:

• Protects the gauge from high-temperature steam

• Traps condensed water inside the loop

• Creates a cooling barrier to prevent hot steam from reaching the gauge internals

How the Assembly Works

1. Steam or hot fluid enters the syphon loop.

2. The loop traps condensed water.

3. This water forms a protective cooling seal.

4. The gauge reads pressure through the cooled liquid.

5. The isolation valve allows the gauge to be safely shut off when required.

Common Industrial Applications

This assembly is commonly used in industries where steam or high-temperature pressure is present:

• Steam boilers

• Steam distribution pipelines

• Autoclaves

• Heat exchangers

• Steam heating systems

• Food and beverage processing

• Palm oil mills

• Chemical and petrochemical plants

Key Advantages

• Protects pressure gauge from heat damage

• Extends gauge service life

• Allows safe isolation during maintenance

• Improves system safety and reliability

• Standard solution for steam applications

Conclusion

A pressure gauge with isolation valve and “O” syphon is an essential assembly for any steam or high-temperature system. It ensures accurate pressure monitoring while protecting the gauge from heat and enabling safe maintenance.

For reliable industrial pressure measurement solutions, choose quality components from VD Valve.