Phosphine (PH₃) is an inorganic compound that is a colorless, highly toxic, flammable liquefied compressed gas at room temperature with active chemical properties. It is odorless in its pure state, but may be accompanied by the smell of acetylene, garlic or rotten fish in industrial preparation or metal phosphide reactions. After inhalation, it quickly enters the human body through the respiratory tract, damaging organs such as the heart, respiratory system, kidneys, nervous system and liver.
一．Working principle of phosphine detector
Electrochemical sensors work by reacting with phosphine gas. When phosphine reacts with the sensitive element of the sensor, a tiny current change is generated. Through the design of the internal circuit, this current change can be converted into a voltage signal, which can be conveniently measured and displayed.
二．How to choose a phosphine detector?
Confined space detection: Phosphine gas detector pump suction is preferred, with a range of 0-2000ppm, which meet the needs of complex environments such as granaries and chemical workshops.
Routine inspection: Single detector (range 0-20ppm, resolution 0.1ppm) is suitable for rapid screening in open areas, response time ≤30 seconds, automatic sound and light alarm when exceeding the standard.
三．Fixed online system
The fixed online system consists of a fixed detector and a control panel. The detector uses an electrochemical sensor, supports RS485/4-20mA output, range: 0-1000ppm, resolution: 1ppm. Suitable for tobacco fumigation, chemical plants and other scenarios. Explosion-proof type, protection level IP65 and above, to ensure long-term stable operation. High-frequency detection, electrochemical detectors have low unit cost and are suitable for long-term use.
Fumigation operation monitoring: 0-2000ppm large-range detector can also be selected.
四．Correct use of phosphine detector
1. Preparation before use
①Confirm that the detector has sufficient power (it is recommended to start with full power), and observe whether the self-test of the display screen is completed normally after starting.
②Check the life of the sensor.
Environmental prejudgment:
①For confined space detection, a pump-suction detector (equipped with an electric sampling pump) must be used to avoid direct exposure of personnel.
②Confirm that the ambient temperature is within the range of -20℃~50℃.
2. Detection operation process
①Power on and calibration: Our detector has been calibrated before leaving the factory, and customers can use it directly after receiving the goods. After that, calibrate once every 6 months or one year to ensure the accuracy of the test results and extend the service life of the sensor.
②Gas sampling: Open area: Handheld detector for natural diffusion sampling, the probe is facing the detection area, 30-50 cm5 from the ground.
Confined space: Use a pump-type detector to collect samples, connect the extended sampling hose, and start the detector to remotely inhale the gas; please stay for a few minutes when sampling to ensure that the gas can fully contact the sensor.
③Reading and recording: Observe the real-time concentration value detected and record the peak data after stabilization. Evacuate immediately when exceeding the standard, and retest and confirm after the concentration drops to a safe value.
3. Post-test processing: Cleaning and maintenance of equipment.
4. Precautions
①Safety protection: Protection must be taken during detection.
②Avoid long-term charging: When charging, please turn off the instrument to reduce the charging time, and then turn it on to charge. Generally, the charging time is about 3 to 6 hours. To protect the effective life of the battery, try not to charge the instrument for more than 6 hours.
③Avoidance of interference factors: Avoid using in high-concentration hydrogen sulfide (H2S) or sulfur dioxide (SO2) environments. Some sensors may be cross-sensitive.
By standardizing the operating procedures and strictly following safety standards, the phosphine detector can ensure efficient and reliable operation safety.