What is a diaphragm pressure gauge? Diaphragm pressure gauge is a precision instrument for measuring fluid pressure in a variety of industrial and commercial uses. In contrast to other pressure gauge types, diaphragm pressure gauges employ a thin but strong diaphragm as the main measuring component. This distinctive architecture enables them to deliver precise and trustworthy pressure readings across a broad array of settings, rendering them essential in numerous sectors.

Basic Structure and Design of diaphragm pressure gauge

Diaphragm pressure gauge structure and principle The diaphragm pressure gauge generally has a housing, a diaphragm, a push rod and a movement mechanism. A diaphragm is a thin and extensible membrane that is mounted horizontally between the upper housing and lower housing (flange) outside the case. The flange's diameter can vary based on the pressure range of the gauge. The larger diaphragm (nominal size 160 mm, or 6 inches) is used for pressure ranges of 100 inches of water column (250 mbar) or less. A smaller diaphragm (nominal size 100 mm, or 4 inches) is used for higher pressure ranges.

How does a diaphragm pressure gauge work?

If fluid pressure deformed the diaphragm, the pressure of the fluid was the same as the pressure of the gas in the tube. Under the influence of fluid pressure applied to the diaphragm, the diaphragm deflects or bends and produces a displacement. A matrix of mechanical linkages translates this displacement into a rotation of the pointer on the gauge face.

Here’s a step-by-step explanation of what the process looks like:

Fluid Pressure Application:

A pressure port from the fluid whose pressure is to be measured connects to the diaphragm.

The diaphragm deflects as fluid pressure increases or decreases, allowing the two parts to separate.

Diaphragm Deflection:

The displacement of diaphragm is directly proportional to the applied fluid pressure.

The amount of deflection varies by the diaphragm's material, thickness and size, and the pressure range for which the gauge is designed.

Push Rod Transmission:

The center of the diaphragm attaches to a push rod.

The diaphragm pushes the vibration rod as it moves, and the vibration rod sends this movement to the measurement mechanism in the gauge.

Movement Mechanism:

This mechanism is called the movement, and it changes the linear movement of the push rod into the rotation of the pointer.

This is normally done by means of a gear, lever, or spring system that multiplies and transfers the curling of diaphragm to the indicator pointer.

Pointer Rotation and Reading:

Attached to the mechanism is a pointer, which rotates about a fixed point.

The exact locati0n of the needle on the gauge display shows the pressure of the fluid being monitored.

The dial pressure gauges usually display range on faces where 1 psi correlates to 0 – 0.2 bar or less.

Advantages and Applications:

Advantages of diaphragm pressure gauges — diaphragm pressure gauges have many advantages over other kinds of pressure gauges:

Accuracy and Precision:

As diaphragm pressure gauges are designed with a sensitive diaphragm, they can provide very accurate and precise pressure readings.

Commonly used in applications requiring accurate pressure measurement, they can be found in process monitoring and control, lab and clinical equipment and medical devices.

Versatility:

Diaphragm pressure gauges can be used to measure very low or very high pressures.

They are versatile and can be adapted to measure other fluid type such as gas, liquid, and steam.

Durability and Reliability:

The diaphragm must be strong enough to withstand high pressures and a wide temperature range, so it is constructed from durable materials such as metal or high-strength polymers.

It makes diaphragm pressure gauges ideal for demanding industrial applications, where severe conditions may be encountered.

Easy to Install and Maintain

Installation and maintenance of diaphragm pressure gauges is easy.

They require very little setup and calibration, and can be easily replaced or maintained if needed.

To sum up a diaphragm pressure gauge is a very precise instrument that employs a sensitive diaphragm to gauge the pressure of fluid. Due to its unique design, it can provide precise and dependable pressure readings in a wide array of environments, making it indispensable across many industries. With knowledge of the basic structure, working principle and advantages of this instrument, we can better use this instrument to monitor and control the pressure of working fluid in the system.