HomeFluid MechanicsMechanical Pressure Gauges: Types, Working, Applications, Advantages

# Mechanical Pressure Gauges: Types, Working, Applications, Advantages

In this post, you will learn what is a Pressure gauge and how it is done with It’s Working principle, Applications, Advantages, Types of pressure gauge and more

## Mechanical Pressure Gauges

Contents

Pressure gauges or Mechanical gauges these are the devices used for measuring the pressure by balancing the column of fluid by spring or dead weight.

## Types of Pressure Gauges

Following are the commonly used mechanical pressure gauges:

1. Diaphragm pressure gauge
2. Bourdon tube pressure gauge
3. Bellows pressure gauge

### 1. Diaphragm Pressure Gauge

A mechanical pressure-measuring instrument used to measure pressure above or below the atmospheric pressure. It is usually employed to measure relatively low pressures. A diaphragm pressure gauge, in its simplest form, consists of a corrugated diaphragm as shown in the figure.

The gauge is connected to the fluid which is under pressure causes some deformation to the diaphragm. With the help of pinion system, elastic deformation of the diaphragm rotates the pointer. This pointer moves over a calibrated scale, which directly gives the pressure.

#### Advantages of Diaphragm Pressure Gauge

1. This is good for low pressure.
2. It is inexpensive.
3. It has a wide range
4. Used to measure gauge, atmospheric and differential.
5. it is very reliable.

#### Disadvantages of Diaphragm pressure gauge

1. Impact resistance is not good.
2. Difficulty in maintenance.
3. Lower measurement pressure.

### 2. Bourdon’s Tube Pressure Gauge

A mechanical pressure-measuring instrument employing as its sensing element a curved or twisted metal tube flattened in cross-section and closed known as Bourdon tube.

It is a device for measuring the pressure of gases or liquids. It consisting of a semicircular or coiled, flexible metal tube connected to a gauge, which records the degree to which the tube is straightened by the pressure of the gas or liquid inside. Generally, it is used for measuring high pressures.

The instrument is connected to the fluid which is under pressure flows into the Bourdon’s tube. As a result of the increased pressure, the tube tends to straighten itself. Since the tube is encased in a circular cover, therefore it tends to become circular instead of straight.

With the help of a simple pinion and sector arrangement, the elastic deformation of the Bourdon’s tube rotates the pointer. This pointer moves over a calibrated scale, which directly gives the pressure.

#### Advantages of Bourdon Tube Pressure Gauge

1. Construction is simple and the cost is low.
2. It has excellent sensitivities.
3. It has high accuracy.
4. This gauge is available for various ranges

#### Disadvantages of Bourdon Tube Pressure Gauge

1. Slow response to a change in pressure.
2. Prone to shock and vibrations.
3. It is subjected to hysteresis.
4. Not available for the low-pressure condition.

#### Application of Bourdon Tube Pressure gauge

1. Gas distribution system.
2. Used in the hydraulic installation.
3. Used in pneumatic installation.

### 3. Bellows Pressure Gauge

It is a device, the pressure responsive element is made of a thin metal tube with a deep circumference when the pressure changes as the elastic elements increase or decrease.

A pointer is connected to it which indicates reading on the circular dial. It expands when the pressure increases and when the pressure is low the elastic elements in the pressure gauge are contracts.