Preface: During this period, customers have been wavering between the choice of gauge pressure and absolute pressure types. So today we will talk about how to choose a board-mounted pressure sensor to achieve the effect of throwing out some ideas. We hope that more professional colleagues will leave messages for discussion.
Pressure, an invisible and immaterial physical quantity, plays an omnipresent role in our daily life and industrial production. From simple tire inflation to complex deep-sea exploration, the accuracy of pressure measurement is crucial. It is not only directly related to the quality of products, but also a core element to ensure production safety and prevent risks. In this context, gauge pressure and absolute pressure, as two basic pressure types in the field of industrial measurement, are becoming increasingly important. This article will guide you to explore these two concepts in an easy-to-understand way, and further extend them to the important application field of airtightness testing, to help you fully understand the key roles they play in modern manufacturing.
Basic Concepts of Pressure
In physics, pressure is defined as the vertical force per unit area. In manufacturing, the role of pressure is much more than that. It not only profoundly affects the shape and structural properties of an object, but is also directly related to the stability and safety of the process. This seemingly simple and straightforward definition, in fact, implies a wide range of potential applications and unlimited possibilities. Whether it’s supporting a towering skyscraper or designing an energy-efficient airplane wing, the concept of pressure plays a vital role everywhere.
1.Gauge Pressure
Definition of Gauge Pressure
Gauge pressure, as the name implies, is a measurement of pressure relative to local atmospheric pressure. It tells us how much the measured pressure is above or below the surrounding air pressure (usually atmospheric pressure).
How Gauge Pressure Works
Gauge pressure measurements determine the amount of pressure by comparing it to atmospheric pressure. If the gauge pressure is positive, the pressure is above atmospheric pressure; if it is negative, the pressure is below atmospheric pressure.
2.Absolute Pressure
Definition of Absolute Pressure
Absolute pressure is a measurement of pressure relative to a complete vacuum. It directly reflects the absolute value of pressure and includes all pressures including atmospheric pressure.
How Absolute Pressure Works
Absolute pressure measurement ignores atmospheric pressure and focuses on the pressure exerted by the object itself.
3.Comparison of Gauge Pressure and Absolute Pressure
Differences in measuring principles
The main difference between gauge pressure and absolute pressure is the difference in reference pressure.
Gauge pressure is measured relative to atmospheric pressure, while absolute pressure is relative to a complete vacuum.
This leads to differences in application and interpretation between the two.
Conversion Relationships
The conversion from gauge to absolute pressure requires consideration of the current atmospheric pressure value.
This is usually achieved by adding or subtracting a standard atmospheric pressure value.
The conversion formula is as follows: – Absolute Pressure = Gauge Pressure + Atmospheric Pressure
– Gauge pressure = Absolute pressure – Atmospheric pressure
Relative vacuum = Absolute vacuum (absolute pressure) – Barometric pressure at the measuring location.
For example: there is a miniature vacuum pump for the absolute pressure of 80kPa, then its relative vacuum is about 80-100 = -20kPa, (the measurement site of the air pressure assumed to be 100kPa) in the ordinary vacuum gauge should be displayed as -0.02MPa.
The customer’s requirement is 1Mpa absolute pressure type products, according to the way of the output signal, we can match to the analog millivolt signal, analog proportional output and digital signal products, here we see what are the options:
≥1MPA≈150PSI Absolute Pressure，abs. accuracy around 0.5% FS
| Analog mV Series | Analog proportional outputs | Digital Output |
|---|---|---|
| WF100S/100E WF162F/162L | WF200S/WF152A | WF5803F / WF100DP / WF183DE / WF200DP / WF280A/282 |
| Factory Calibration | Factory Calibration | Factory Calibration |
| WF100E | WF152A | WF183DE |
Other details are not listed yet, please contact us for more options.
Core Applications of Pressure Measurement in Manufacturing
1.First, quality control: precision and reliability of the “master quality inspector”.
In the vast arena of manufacturing, pressure measurement is undoubtedly the product quality control field of “quality control master”. It is its keen insight and rigorous attitude to ensure that each product can meet the established quality standards. In the injection molding process, accurate control of the pressure in the mold, not only to ensure that the product size is accurate, but also effectively reduce the rate of defective products, improve overall production efficiency. In the food packaging industry, pressure measurement has become the “invisible shield” that guards the freshness of food products, ensuring that food products are protected from external contamination during transportation and storage through rigorous sealing tests, safeguarding the health and safety of consumers.
2. Process monitoring: the “production guardian” for efficiency and stability
In every step of the production process, pressure measurement plays an important role as the “production guardian”. It is like a conscientious supervisor, always paying attention to the pressure changes in the production process, to ensure that all operations are carried out in a safe and stable range. In the chemical industry, pressure monitoring in the reactor is particularly important. Once the pressure rises abnormally, the system will immediately issue an alarm to avoid potential safety risks. At the same time, in the fluid transportation pipeline, the accurate control of pressure measurement can effectively prevent the occurrence of “running, risking, dripping, leaking” and other problems, to protect the production environment and the effective use of resources.
3. Safety standards: strict and reliable “safety guards”.
In the manufacturing industry, safety always comes first. Pressure measurement as an important tool to ensure the safety of equipment and working environment, its importance is self-evident. It is like a loyal “safety guard”, always guarding the safety and stability of the production site. For boilers, pressure vessels and other high-pressure equipment, real-time monitoring of pressure measurement and early warning function can effectively prevent the occurrence of “pressure burst” and other serious accidents. In the management of industrial gas storage tanks, the precise control of pressure measurement is the key to avoid accidents. Through the implementation of these measures, we can ensure that every aspect of the production process meets the requirements of safety standards, laying a solid foundation for the sustainable development of enterprises.
Gas Tightness Testing vs Gauge Pressure
Gastightness testing is the process of evaluating whether a product or device has leaks or defects by measuring whether it can remain stable under pressure to ensure that the product does not have quality problems.
Gauge pressure sensors are commonly used in gas-tightness testing equipment to determine whether there are leaks or defects by measuring the pressure difference between the inside and outside of a product component. It plays a key role in industries such as automotive parts, consumer electronics, food packaging and medical devices to ensure product quality and safety.
Gauge pressure measurements offer significant advantages in gas tightness testing: High accuracy: detects small leaks
Fast response: results are displayed in real time
Repeatability: suitable for batch testing
Non-destructive: no damage to the object under test
By combining gauge pressure measurement and leak testing, the manufacturing industry can more effectively ensure product quality and productivity while ensuring safety standards are met.
