What is a Bellows Pressure Gauge Advantages Uses & Working Principle

Published: 8 Jul 2025

Want to understand the bellows pressure gauge? In this post, we’ll explain what it is, how it works, and where you can find it—everything you need to know. Let’s keep it easy and interesting!

What is a Bellows Pressure Gauge?

A bellows pressure gauge is a tool made with a thin, flexible metal tube shaped like a bellow. It measures pressure like absolute, differential, or gauge pressure. The bellows grow or shrink when pressure changes. This action turns the pointer to show pressure. The gauge responds quickly, making it reliable and easy to read.

Construction of Bellows Pressure Gauge

The main parts include:

A metal bellows (flexible and sealed)
A pointer and scale
A spring or mechanical linkage
A pressure inlet

Everything is inside a strong case. When pressure flows in, it presses against the bellows.

Bellows Pressure Gauge Working Principle

It works through the movement of a metal bellows.
When pressure enters the gauge, it pushes against the bellows. The bellows expand or shrink depending on how strong the pressure is.
This movement is sent to a pointer through a small gear or lever system. The dial pointer indicates the pressure.
It’s that simple! When the pressure increases, the bellows expand, and the pointer moves.

Types of Bellow Pressure Gauge

There are a few types, such as:

Single Bellows Gauge

This type checks gauge pressure, which means it compares the pressure to the surrounding air. It is easy to use and works well for low-pressure systems.

Double Bellows Gauge

This one has two bellows inside. Measures both absolute and differential pressure. It is more accurate and helps when you need to compare two pressures or get a very exact result.

Spring-Controlled Bellows

This type has a spring to help control movement. It makes the readings steadier and more reliable. It’s used when pressure changes quickly.

Advantages of Bellows Pressure Gauge

Why use it?

Simple and easy to use
No need for electricity
Good for low-pressure readings
Compact and light
Can work in tough environments

Application of Bellows Pressure Gauge

You’ll find these gauges in many places:

HVAC systems
Medical equipment
Low-pressure gas lines
Industrial machines
Scientific labs

They’re great for measuring small changes in pressure

Conclusion:

The bellows pressure gauge is easy to use and reliable. It helps measure pressure without any power. It’s used in many fields and works well in both light and tough settings.