Pressure Gauge and 6 Key Considerations

The Important Role of Pressure Gauges

Pressure gauges are essential tools across various industries worldwide. From manufacturing to healthcare, they play a vital role in measuring the pressure of gases and liquids within systems. Understanding their history, how they work, and their maintenance ensures they continue to operate accurately and reliably. Let's delve into these indispensable instruments.

Pressure Gauge History & Development

Overall, the development of pressure gauges has undergone an evolution from liquid columns → mechanical → electrical signals → to the current era of intelligence.

Around the 17th century, the Italian scientist Evangelista Torricelli invented the mercury barometer, proving the existence of atmospheric pressure. Shortly after, Otto von Guericke conducted the famous "Magdeburg hemispheres" experiment, once again perceiving and measuring atmospheric pressure. In the mid-19th century, French engineer Eugène Bourdon invented the Bourdon tube pressure gauge, which uses a curved metal tube that straightens under pressure, converting pressure into mechanical displacement displayed by a pointer on a dial. 

From the early to mid-20th century, pressure gauges diversified with the development of various types including diaphragm pressure gauges, bellows pressure gauges, manometers, as well as shock-resistant and liquid-filled models. In the late 20th century, with the advancement of electronic sensing technology, pressure sensors and transmitters with electrical signal outputs emerged. Subsequently, following the trend towards intelligence and connectivity, pressure measurement entered an era of "smart, connected, and self-diagnosing" devices.

How do Pressure Gauges Work?

Pressure gauges measure the force exerted by a liquid or gas on the wall of a container (usually a pipe or tank). This force is converted into a readable value on the gauge. The typical working principle of pressure gauges is as follows:

Mechanical Pressure Gauges (Bourdon Tube): The most common design for mechanical pressure gauges uses a curved tube called a Bourdon tube. When pressure is applied, the tube straightens slightly. This movement is transmitted to a pointer on the dial, displaying the pressure reading. These gauges are ideal for medium to high-pressure applications.

Digital Pressure Gauges: Digital pressure gauges use electronic sensors to measure pressure. These sensors detect pressure changes and convert them into electrical signals, which are then displayed on a digital screen. These gauges are often more precise and easier to read, especially in environments where exact readings are crucial.

Smart Wireless Pressure Sensors: Smart wireless pressure sensors convert pressure signals into electrical signals. After digital processing, the data is uploaded to the cloud via wireless communication, enabling real-time pressure monitoring, analysis, and remote control.

What is Calibration of a Pressure Gauge?

Pressure gauges must be calibrated regularly to maintain their accuracy, especially Bourdon tube gauges. The calibration process involves comparing the gauge's pressure reading against a known reference standard. Over time, gauges can deviate or lose accuracy due to factors like wear and tear, aging, or damage.

Calibration Steps:

Use a Reference Standard: Use a calibrated reference pressure gauge or a deadweight tester as a standard to compare the readings of the gauge under test.

Adjust the Gauge: If the gauge reading is inaccurate, adjustments may be necessary. Some gauges have an adjustment screw for easy calibration, while others might require professional calibration.

Record the Calibration: For quality assurance, it is crucial to record the calibration results, especially in highly regulated industries.

What does an Application Pressure Gauge Do?

Manufacturing: Pressure gauges are used to monitor hydraulic, pneumatic, or steam systems, ensuring normal operation and safety.

Oil, Chemical, and Energy Industries: Pressure gauges monitor process pressures of fluid media, ensuring reaction safety and preventing explosions or leaks. They are used alongside pressure transmitters for automated control.

Water Treatment and Environmental Protection: Pressure gauges monitor filtration pressure differentials, prevent membrane fouling, achieve water supply system pressure balance, and check pump operational status and energy consumption.

Automotive and Transportation: Pressure gauges are used for automotive tire pressure monitoring, brake systems, hydraulic systems, aircraft hydraulic cabins, and railway brake systems.

Medical and Life Sciences: Pressure gauges are used in medical oxygen cylinders, ventilators, anesthesia machines, laboratory gas supply systems, sphygmomanometers, and negative pressure suction equipment.

Maintenance of Pressure Gauges

Although the Bourdon tube pressure gauge has a metal housing and a robust structure, it still requires regular maintenance.Proper maintenance ensures that pressure gauges continue to work effectively and provide accurate readings. Here are some tips for maintaining pressure gauges:

Regular Inspection: Visually inspect the gauge for any signs of damage, such as surface cracks or corrosion. Check for any debris that might obstruct the pointer's movement.

Clean the Gauge: Ensure the gauge surface is free from dirt, grease, or other substances that could affect its accuracy. A clean surface helps prolong the gauge's life.

Avoid Overpressure: Never subject the pressure gauge to pressure exceeding its rated capacity. Overpressure can damage internal components, leading to inaccurate readings or failure.

Protect from Harsh Environments: If the gauge is used in corrosive or extreme conditions, consider using protective coatings or installing pressure snubbers to reduce vibration.

Regular Calibration: Regular calibration is essential for maintaining the accuracy of pressure gauges. The frequency depends on the criticality of the application, typically annually or semi-annually.