Infrared technology

Gases containing more than one atom can absorb infrared light, so that hydrocarbons and some gases such as carbon dioxide and carbon monoxide can be detected by infrared technology.

In order to distinguish infrared absorption, gas and other substances from water, an additional sensor with a wavelength bandwidth of 2.7-3um is required. Hydrocarbons have no absorption peak in this range. This prevents false alarms from occurring and reduces the signal of interfering substances. The double beam design is used to prevent optical component pollution from causing false alarm.

Advantages of infrared technology

1. Faster reaction rate: the response time is generally less than 7 seconds;

2. Automatic fault operation: power supply error, signal error and software error can be fed back to the control system;

3. Strong anti-interference ability to the signal of polluting gas;

4. Long service life, generally more than 10 years;

5. Low maintenance cost;

6. No oxygen required;

7. It will not burn out under the condition of high concentration of combustible gas;

8. No sintering and corresponding problems will not occur;

Disadvantages of infrared technology

Purchase price is higher than catalytic combustion detector

Catalytic combustion needs to be tested regularly (through standard gas). Some offshore oil platforms usually need to be tested every six weeks and replaced every 3-5 years, which will cost a lot.

The infrared gas detection instrument that will not sinter can detect itself, which can greatly reduce the possibility of problems compared with detecting such unrecoverable problems as lamps, sensors, windows, software, etc. Less zero point, range drift and high sensitivity mean less calibration and routine maintenance of infrared gas detection instruments, generally 6-12 months.

At the same time, the price of infrared sensors has dropped significantly in recent years. Although the price is still higher than that of catalytic combustion detectors, practical experience shows that the cost of infrared sensors can be reduced by reducing maintenance costs. Therefore, it is a general trend that infrared gas sensing technology replaces catalytic combustion technology.