A Brief Analysis of the Installation and Maintenance of Gas Detectors
Gas detectors are mainly divided into two types: portable gas detectors and handheld gas detectors. They are instruments and tools that use sensors to detect toxic and harmful gases in the environment and issue warnings. When using gas detectors, it is necessary to install them correctly to ensure normal use. Below, we will briefly introduce and understand them.
Installation of gas detector
The first step is to install the gas detector in an area where there may be gas leakage. The installation of the gas detector must be firm, and the installation position is determined by the specific gravity of the measured gas relative to air. As the specific gravity of the measured gas is smaller than that of air, the detector should be installed at a distance of 30-60cm from the ceiling. Fix the detector to the wall with expansion screws.
However, in order to ensure the correct use of the detector and prevent its malfunction, the following are precautions (in areas that are not easy to install):
1. Places with temperatures below -40 ℃ or above 70 ℃
2. Places with high airflow, such as air vents, ventilation fans, doors, etc
3. Places with high levels of water vapor and droplets (relative humidity: greater than 90%)
4. Places directly affected by steam and oil fumes
The second step is wiring: Highly shielded wires should be used to prevent interference with electrical signals. The wires should be arranged properly and the top cover should be opened.
1. The gas detector of a gas detector generally adopts a three wire transmission system. The positive terminal of the power supply (marked as "VCC" terminal), the signal line (marked as "SIG" terminal), and the negative terminal of the power supply (marked as "GND" terminal) are respectively connected to a set of terminals labeled as "4-20mAIN" in the channel module, with "24V, mA, and GND". The chassis ground (shielding network of the cable) is well grounded, and after connecting the wires, the chassis is fastened.
2. Start: Wiring completed, power supply to detector. After startup, the reading will go from over range to stable, which takes about 15 minutes.
In addition to proper installation, one should also be familiar with simple maintenance.
1. Sensor maintenance: Generally, re inspection and calibration are required after six months to one year of installation and use, and a testing report should be issued by the testing party.
2. When the sensor of a gas detector loses sensitivity, it needs to be replaced. Metal tube float flow meters, turbine flow meters, and vortex street flow meters can determine whether the sensor has failed through regular calibration. When the calibration value cannot reach the standard gas value, the sensor needs to be replaced.
3. Whole machine inspection of gas detector: The detector should be checked regularly, and its signal current in clean air is DC4mA. 1. Pre distillation:
Transfer 50 ml of boric acid solution (ρ=20 g/L) into the receiving bottle, ensuring that the outlet of the condenser tube is below the level of the boric acid solution. Take 250 ml of sample and transfer it into a flask. Add a few drops of bromothymol blue indicator (ρ=0.5 g/L). If necessary, adjust the pH to 6.0 (yellow indicator)~7.4 (blue indicator) with sodium hydroxide solution (c (NaOH)=1 mol/L) or hydrochloric acid solution (c (HCl)=1 mol/L). Add 0.25 g of light magnesium oxide and several glass beads, and immediately connect the nitrogen ball and condenser tube. Heat distillation to achieve a distillate rate of approximately 10 ml/min. When the distillate reaches 200 ml, stop distillation and add water to make up to 250 ml.
