Compressed air is very common in industrial processes. Measuring the pressure of compressed air can ensure the safety of operators. It can be used for flammable, explosive and corrosive gases. So, how to measure the pressure of compressed air? That is the compressed air pressure sensor. This chapter will introduce the compressed air pressure sensor in detail.
What is a Compressed Air Pressure Sensor?
A compressed air pressure sensor is an important device commonly used in industrial equipment. It can convert the pressure signal of compressed air into an electrical signal. It outputs the signal to the controller, which monitors and controls the pressure.
Sini-Inst’s compressed air pressure sensor can measure flow and temperature. Sino-Inst’s compressed air pressure sensor supports customization. Don’t hesitate to get in touch with us. Sino-Inst’s professional engineers can provide you with a suitable measurement solution.
What is Compressed Air?
Compressed air is air compressed by an external force. Air is compressible. Air that has been reduced in volume and increased in pressure by the air compressor doing mechanical work is called compressed air. Compressed air is an important source of power. Compared with other energy sources, it has the following obvious characteristics: clear and transparent. Convenient to transport. No special harmful properties. No fire hazard. Not afraid of overload. Compressed air can work in many adverse environments, and air is inexhaustible.
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How does the Compressor Air Pressure Transducer Work?
The principles of common compressed air pressure sensors are as follows.
Strain principle:
Use the deformation of the material under pressure to measure pressure. The strain gauge is attached to the elastic element. When the elastic element is deformed by pressure, the resistance value of the strain gauge will change. The pressure is calculated by measuring the change in resistance.
Capacitive principle:
Use the change in capacitance between two conductive plates to measure pressure. When the pressure change causes the distance between the conductive plates to change. The capacitance will also change. The pressure is calculated by measuring the change in capacitance.
Piezoelectric principle:
Use the change in charge generated by certain materials (such as quartz) under pressure to measure pressure. Piezoelectric materials will generate charges on their surfaces when they are under pressure. The pressure is calculated by measuring the change in charge.
Piezoresistive principle:
The pressure is measured by the change in the resistance value of semiconductor materials under pressure. The resistance value of semiconductor materials will change with the change of pressure. The pressure is calculated by measuring the change in resistance value.
What are the Three Types of Pressure Transducers?
The pressure types mainly include gauge pressure, absolute pressure and differential pressure.
Pressure transmitters can be divided into the following types according to the measured pressure type:
Differential pressure transmitter:
The differential pressure transmitter is used to prevent the medium in the pipeline from directly entering the transmitter. The pressure-sensitive diaphragm and the transmitter are connected by a capillary filled with fluid. It is used to measure the liquid level, flow rate and pressure of liquids, gases or steam. Then the pressure is converted into a 4~20mA DC signal output.
Absolute pressure transmitter:
The absolute pressure transmitter is a new series of products. It is used for vacuum measurement and control. The absolute pressure transmitter completely solves the problem of difficult vacuum measurement.
Gauge pressure transmitter:
A gauge pressure transmitter is an instrument for measuring pressure. A gauge pressure transmitter is mainly used to convert a pressure signal into a standard electrical signal. and it outputs a signal to a control system or instrument.
In industrial production, it is often necessary to monitor and control the pressure of materials. A gauge pressure transmitter can provide a high-precision and high-stability pressure signal. Gauge pressure transmitter is widely used in petroleum, chemical, pharmaceutical, food and other fields. It is an indispensable and important part of the industrial automation production process.
According to the working principle, pressure transmitters can be divided into seven categories.7 Types of Pressure Sensors: Different Types, Working Principles, and Definitions
Compressed Air Pressure Sensor Applications
Compressed air pressure transmitter is widely used in petroleum, chemical, pharmaceutical, food and other fields. It is an indispensable and important part of the industrial automation production process.
In the air compressor safety management system, a compressed air pressure sensor is used to control the side airbag.
In industrial air compressors:
Compressed air pressure sensors can be used to measure inlet and outlet pressures, filter pressure drop, cooling water inlet and outlet pressures, and compressor oil pressure.
In pneumatic applications:
Compressed air pressure sensors can be used to measure and control the pressure of high-pressure compressed air and gases.
In air compressors
Compressed air pressure sensors convert the measured compressed air pressure into a digital or analog electronic signal. Compressed air pressure sensors enable precise control in manufacturing, construction, chemical, pneumatic tool, oil and gas, food and beverage industries, and medical equipment applications.
Sensors are commonly used for two types of pressure measurements:
(1) Determine if the compressed air output to the equipment is appropriate
(2) Monitor air pressure leaks for pressure line maintenance.
Sino-Inst’s compressed air pressure sensor customization case:
- Medium: compressed air
- Range: 0 to 16 Bar
- Output: 4 – 20 mA
- Supply voltage: 24 V DC
- Operating temperature: up to 220 degrees Celsius
- Sampling frequency: 2000~3000Hz
- Response time: 0.2 m/s
- Vibration resistance: 1000 Hz
- Accuracy: 0.25%
- Process connection: 1/4 inch NPT
Compressed Air Pressure Sensor Order Guide
1. According to the type of pressure to be measured
The pressure types mainly include gauge pressure, absolute pressure, and differential pressure. Gauge pressure refers to the pressure that is less than or greater than atmospheric pressure based on the atmosphere.
Absolute pressure refers to the pressure that is higher than the absolute pressure based on the absolute pressure zero point
Differential pressure refers to the difference between two pressures.
2. According to the measured pressure range
In general, the actual measured pressure is selected as 80% of the measurement range.
The maximum pressure of the system should be considered. Generally speaking, the maximum pressure range of the pressure transmitter should reach 1.5 times the maximum pressure of the system.
Some water pressure and process control have pressure spikes or continuous pulses. These spikes may reach 5 or even 10 times the “maximum” pressure, which may cause damage to the transmitter.
Continuous high-pressure pulses, close to or exceeding the maximum rated pressure of the transmitter. It will shorten the practical life of the transmitter.
However, increasing the rated pressure of the transmitter will sacrifice the resolution of the transmitter. Buffers can be used in the system to weaken the spikes, which will reduce the response speed of the sensor.
Pressure transmitters are generally designed to withstand the maximum pressure for 200 million cycles without reducing performance.
3. According to the measured medium
According to the different measured media: dry gas, gas liquid, highly corrosive liquid, viscous liquid, high-temperature gas liquid, etc.
Correct selection according to different media is conducive to extending the service life of the transmitter.
4. According to the maximum overload of the system
The maximum overload of the system should be less than the overload protection limit of the transmitter, otherwise, it will affect the service life of the transmitter or even damage the transmitter.
Usually, the safety overload pressure of the pressure transmitter is twice the full scale.
5. According to the required accuracy
The measurement error of the transmitter is divided according to the accuracy level. Different accuracy corresponds to different basic error limits (expressed as a percentage of the full scale output).
In practical applications. The selection is based on the control requirements of the measurement error and the principle of economic use.
6. According to the operating temperature range of the system
The temperature of the measuring medium should be within the operating temperature range of the transmitter. If it is used at an overtemperature, a large measurement error will be generated. And the service life of the transmitter will be affected.
In the production process of the pressure transmitter, the temperature effect will be measured and compensated to ensure that the measurement error caused by the temperature effect is within the accuracy level requirement.
In high-temperature situations, you can consider choosing a high-temperature pressure transmitter. Install auxiliary cooling measures such as condensers and radiators.
7. According to the compatibility of the measuring medium and the contact material
In some measuring occasions, the measuring medium is corrosive. At this time, it is necessary to select materials compatible with the measuring medium. Or perform special process treatment.
8. According to the pressure interface form
Flange connection, threaded connection, clamp connection and hose connection, etc.
9. According to the power supply and output signal
Usually, the pressure transmitter is powered by a DC power supply and provides a variety of output signal options, including 4~20mA. DC; 0~5V. DC, 1~5V. DC, 0~10mA. DC, etc., and can have RS232 or RS485 digital output.
10. According to the on-site working environment and other conditions
Whether there is vibration and electromagnetic interference, etc., relevant information should be provided when selecting the model so that corresponding treatment can be taken.
Sino-Inst’s compressed air pressure sensor supports customization. Sino-Inst’s compressed air pressure sensor has many models for you to choose from.
If you have any instrument-related questions. Please contact us. Our professional engineers will customize a solution for you.
