عملکرد سنسور یا دتکتور گازی چگونه است؟
دتکتور گاز، میزان گاز تزریق شده به سنسور را با تاخیر از طریق سیگنال خروجی نمایش می دهد و زمان پاسخ اکثر دتکتورهای گاز به گاز تزریق شده به سنسور به صورت نمایی می باشد.
Definition of "Response Time"
In gas detectors, the "response time" feature is usually defined as follows:
It takes a while for a gas meter to show 90% of the volume of gas injected into the sensor at the output and is expressed in T90. For example, if 100% LEL is applied from a gas to a sensor, the T90 of this sensor will take up to 90% of the LEL to last. (When comparing the performance of different sensors, we should note that in the United States and some other countries, a lower scale of T60 is considered.) Give. Therefore, it is wrong to indicate the response time of gas detectors in an absolute volume, and when a gas with volume A is injected into its sensor, it can only be said that the detector detects and shows at what time what percentage of 90% A or 60% Give.
Factors Affecting "Response Time"
Sensor type and gas detection process
T90 is usually between 30 and 60 seconds for electrochemical gas sensor sensors and between 20 and 30 seconds for catalyst type sensors. Infrared gas meters give a faster response to the gas injected into the sensor so that the T90 reaches below 10 seconds.
Electronic signal processing time in detector
Gas transmission time to the sensor
For example, for gas sampler detectors, the time to transfer gas to the sensor is the length and diameter of the sampler tube, the suction and sampling rate, and the rate of gas diffusion from the fluid location to the BAGGS sensor.
Determine the "response time" required
Determining the "response time" required depends on the following factors:
Detector installation location
The purpose of using the detection system
The speed of the spread of predictable events
Protecting people against gas settling requires less and faster response time, but if we are facing low gas settling speed and low compression speed, high and slow response time is acceptable.
Also, the alarm level should be considered in proportion to the response time. For example, a longer response time is acceptable when a lower alert level is considered for the same gas rate and installation position. (For example, the LEL10% alert level should be considered instead of LEL25%).