Applying pressure to a diaphragm causes it to displace due to its elastic nature. This sort of pressure gauge will use the diaphragm’s elastic property to determine the difference between the reference and unknown pressures.
The Bourdon gauge’s functioning principle is the same as this device. The main difference between this gadget and a Bourdon gauge is that it has a corrugated diaphragm rather than a Bourdon tube.
If we attach this gadget to any gauge point, the diaphragm will deform elastically. Due to its small size, people commonly utilize this type of pressure gauge. The diaphragm pressure gauge excels in low-pressure applications.
Well, in this reading, we’ll explore what a diaphragm pressure gauge is, its applications, parts, diagram, types, and how it works. We’ll also explore its advantages and disadvantages.
Let’s Begin!
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What is a Diaphragm Pressure Gauge?
A pressure gauge with a diaphragm is one that measures pressure using a diaphragm. A diaphragm, also known as a flexible material, typically consists of thin metal, leather, rubber, cloth, or other similar materials.
The membrane device is used to measure the difference between two different pressures, and the working principle of the pressure gauge with a diaphragm is based on the resilience properties of metal/thin plate due to the curvature of iteration pressure at the membrane plane.
The membrane separates the pressure gauge’s inner working components from the media, preventing contamination. This feature allows the diaphragm pressure gauge to work with corrosive or contaminated liquid or gaseous media.
Applications
Several industries have successfully used diaphragm pressure gauges for both absolute and differential pressure measurement applications. Due to its capacity to separate media and prevent contamination, it is suitable for applications seeking purity.
It’s also suitable for industries that work with corrosive fluids. The following industries may benefit from the use of a diaphragm pressure gauge:
- Food and beverage
- Pharmaceutical
- Petrochemical
- Mining
Additionally, vacuums, air compressors, hydraulic applications, and swimming pool filters use the diaphragm pressure gauges.
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Diagram
Types of Diaphragm Pressure Gauge
The following are the various types of diaphragm pressure gauges:
Metallic Diaphragm Gauge
Brass or bronze serves as the construction material for its thin, flexible diaphragm. The diaphragm moves, which controls an indicating or recording instrument.
This gauge’s versatility and portability make it ideal for use or installation in moving equipment such as airplanes.
Slack Diaphragm Gauge
Because the fluctuations are minor, measuring pressure below atmospheric pressure is more challenging. Only 14.7 psi (1 kg/cm2) separates air pressure from the complete vacuum. It is more difficult to measure pressure here.
You can use a slack diaphragm gauge with a weak spring and a large area (torr) to measure overpressure ranges as low as 0.01–0.40 mm Hg. It is possible to attain 1-2 percent accuracy.
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How Does Diaphragm Pressure Gauge Work?
A diaphragm pressure gauge operates in a less complex and easily understandable manner. The diaphragm (B), a thin circular metal sheet that can be flat or corrugated, forms the basis of the figure.
Applying pressure should result in a linear diaphragm deflection. A flat diaphragm can guarantee only tiny deflections. For industrial applications, a corrugated diaphragm is the preferred option.
You can either weld or clamp the diaphragm in place between the flanges. Normally, clean applications prefer the welded diaphragm to prevent any potential leakage.
The diaphragm separates the gauge’s environment, exposing one side to the ambient while sealing the other. When working with corrosive or viscous fluids, this media separation protects the internal gauge components.
As pressure enters the system through the inlet (D), the diaphragm deflects. The link (A) and gears translate this deflection into pointer (C) movement, enabling a precise measurement of the pressure change.
People commonly express pressure in bar or psi (pounds per square inch), and several accuracy grades indicate the maximum deviation.
Advantages and Disadvantages of a Diaphragm Pressure Gauge
Advantages:
- They are quite sensitive.
- It has the ability to detect fractional pressure variations in the microsecond range.
- It merely requires a smaller amount of area.
- This type of pressure measurement apparatus measures low pressure, vacuum, and differential pressure.
- It is suitable for usage in corrosive environments.
Disadvantages:
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Conclusion
The Diaphragm Pressure Gauge is a highly versatile and sensitive instrument used to measure low to medium pressure, especially in corrosive or viscous media. It uses a flexible diaphragm that deflects under pressure, transferring movement to a mechanical linkage that drives a pointer on the dial.
A pressure gauge with a diaphragm is one that measures pressure using a diaphragm. Typically, thin metal, leather, rubber, cloth, or other similar materials construct the diaphragm, a flexible material also known as a membrane.
These gauges are commonly used in chemical, pharmaceutical, food processing, and sanitary applications, offering excellent accuracy and media isolation. Their ability to measure pressure in challenging environments makes them an essential tool in modern industry.
Frequently Asked Questions (FAQs)
What is a diaphragm pressure gauge?
It’s a pressure-measuring device that uses a thin, flexible diaphragm to sense pressure changes, ideal for low-pressure or corrosive applications.
Where is a diaphragm pressure gauge typically used?
In chemical processing, pharmaceuticals, sanitary processes, gas systems, and viscous or corrosive fluid environments.
What are the advantages of a diaphragm pressure gauge?
- Suitable for corrosive, viscous, or sludgy media
- Ideal for low-pressure ranges
- Provides isolation from the process media
- Can be combined with electrical contacts for control systems
- Hygienic and easy to clean options available
What is the pressure range for diaphragm pressure gauges?
Typically used for low to medium pressures, ranging from 10 mbar to a few bars.
What materials are used for diaphragms?
Common materials include stainless steel, PTFE, Hastelloy, and Monel, depending on media compatibility.
How is the diaphragm protected from harsh media?
By using chemical seals, coatings, or selecting corrosion-resistant diaphragm materials.
Can diaphragm pressure gauges be used for sanitary applications?
Yes, sanitary diaphragm gauges with tri-clamp connections and smooth surfaces are used in the food, dairy, and pharma industries.