Gas flow sensors are widely used in various fields of industrial production because their measurement accuracy is unaffected by the temperature, pressure, and viscosity of the fluid being measured. Today, the Transmission Network editor will share some key points about the use and application areas of gas flow sensors.
Key points for using gas flow sensors
1. During operation, when the gas flow rate suddenly changes, heat transfer and temperature redistribution within the pipe are necessary, so the output signal requires a certain amount of time to stabilize. To reduce this hysteresis, gas flow sensor manufacturers often add differential networks to the electrical circuitry to enable a rapid response in the output signal. This is especially important when working with other instruments for automatic flow control.
2. Because this type of gas flow sensor can only function properly under relatively stable gas specific heat conditions, it is unsuitable for use in situations where the gas composition is unstable, the gas contains mist, or the operating conditions approach the gas's liquefaction critical region, due to the highly unstable specific heat value. For example, the liquefaction critical point of Znene is 50 kg / cm² , 9.9 ° C . During testing, it was found that the gas flow sensor readings began to become unstable when the pressure exceeded 30 kg / cm² . Through long- term research and development of gas flow sensors, the types of gas flow sensors have increased significantly, and they are widely used in industrial measurements. Therefore, we should strictly adhere to the key points of their use in industrial applications.
Application areas
Gas flow sensors (or airflow sensors) used in anesthesia machines measure the flow rates of air, oxygen, and nitrous oxide, ensuring the gas composition supplied to the patient is appropriate and meets the standards set by the doctor. Thermistor temperature sensors monitor the temperature and humidity of the air delivered by the anesthesia machine, ensuring patient comfort and preventing throat pain caused by inhaling dry, cold air.
An airflow sensor used in sleep apnea machines sends a signal to the machine to reduce the speed of the fan when the patient begins to exhale, so as to prevent the patient from feeling uncomfortable as if they are "fighting" against the machine . A humidity sensor monitors the humidity of the air, measuring its dew point and moisture content, in order to provide the patient with air of appropriate humidity.
Gas flow sensors used in air purifiers primarily function to adsorb floating particulate matter and harmful substances in indoor environments. Similarly, in certain industrial applications, gas flow sensors provide workers with a safe and clean breathing environment. However, compared to consumer air purifiers, industrial air purifiers are more powerful and handle more complex harmful gases and substances. In industrial air purifiers, timely replacement of the filter, which uses activated carbon as its main component for particulate adsorption, is crucial, and the use of gas flow sensors facilitates this monitoring.
In some industrial settings, the concentration of dust particles and harmful substances in the air, both inherent to the environment and generated by the work, is higher than in daily life. Therefore, the activated carbon filter in the air purifier is consumed more quickly during adsorption, losing its filtering effect. To address this, a gas flow sensor detects the airflow velocity at the other end of the filter. When the filter approaches "saturation"—meaning the airflow velocity drops below a set value due to obstructed airflow—an alarm is triggered, notifying staff to replace the filter and ensuring the purifier's efficiency. The Siargo FS4001 gas mass flow sensor, offered by ICbuy.com, utilizes proprietary MEMS flow sensor and packaging technology. This sensor measures from 0 to 30 sccm to 0 to 1000 sccm . The flow rate for each model is achieved through specially designed packaging and intelligent electronics to achieve appropriate sensitivity.
The packaging is made of chemically inert and thermally stable polycarbonate material. A high pressure rating of 5 BAR ( 73 PSI ) is achieved thanks to Siargo's unique MEMS chip structure, special packaging technology, and rugged sensor housing. Furthermore, the FS4001 can be used in a wide range of applications including instrumentation (such as gas chromatography-mass spectrometry), leak detection, process control, gas flow metering, and medical applications. The FS4001 requires an 8–24 VDC power supply to provide an analog and/or digital user interface. The analog output is linear , responding linearly from 0.5 to 4.5 VDC from 0 to full scale flow rate. The digital output is transmitted via RS232 . The RS232 communication protocol can be found in this manual.
The functional block diagram is shown below. The MEMS sensor chip's sensor drive circuit provides power and transmits a flow-related voltage converter. The microcontroller processes the 19th letter of the English alphabet.
(Amplification, filtering, etc.) converts voltage into flow rate. The flow rate signal is transmitted via analog or analog-digital format ( RS232 ).
