Low-temperature environments (such as below -20℃) can lead to problems like increased viscosity of the lubricating oil in the hot air blower, decreased battery performance, and reduced sensitivity of electrical components, directly affecting the start-up performance of the equipment. The following provides a systematic inspection plan from three aspects: pre-startup inspection, startup process monitoring, and post-startup performance verification.
First, check before startup
1. Lubrication system inspection
Lubricating oil condition:
Check whether the lubricating oil has thickened or solidified due to low temperature. If the fluidity of the oil is poor, it needs to be replaced with low-temperature lubricating oil (such as ISO VG 32 or a lower viscosity grade).
Case: The hot air blower in a certain factory got stuck in the gearbox due to the solidification of lubricating oil in an environment of -30℃, and the repair cost exceeded 50,000 yuan.
Lubricating oil level
Make sure the oil level is between 1/2 and 2/3 of the oil window to avoid false drops in the oil level due to low temperature (thermal expansion and contraction effect).
2. Electrical system inspection
Battery status (if applicable) :
Measure the battery voltage. At low temperatures, the battery capacity may decrease by 30% to 50%. If the voltage drops below 80% of the rated value, the battery needs to be charged or replaced.
The capacity of a 12V lead-acid battery may drop to 6V at -20℃, causing the motor to be weak when starting.
Cables and terminal blocks:
Check whether the insulation layer of the cable has become brittle and cracked due to low temperature, and whether the terminal blocks are loose or oxidized.
Use an infrared thermometer to check the temperature of the terminal blocks. If the local temperature abnormally rises (> 50℃), they need to be tightened or replaced.
3. Heating elements and sensors
Heating element:
Check whether the heating tube or PTC ceramic is damaged, and measure the resistance value with a multimeter (the deviation from the standard value should be less than ±10%).
Temperature sensor
Verify the accuracy of the temperature sensor to ensure that it can accurately feedback the ambient temperature and equipment temperature.
4. Inspection of mechanical components
Fans and impellers
Manually rotate the fan to check if it gets stuck or makes abnormal noises. If the rotational resistance is large, the accumulated ice or the bearings need to be cleaned or lubricated.
Air inlet and outlet:
Clear the snow or frost to ensure the air ducts are unobstructed.
Second, startup process monitoring
1. Starting current and voltage
Record data:
Monitor the current (which should be ≤ 3 times the rated current) and voltage (fluctuation should be ≤±10%) at the moment of startup using a clamp-on ammeter and a voltmeter.
Exception handling:
If the starting current is too large or the voltage fluctuates sharply, it is necessary to check the circuit load or power supply capacity.
2. Startup Time and Response
Standard time:
The time from the start-up of the hot air blower to its normal air output should be no more than 2 minutes. If this time is exceeded, it is necessary to check for faults in the heating element or the fan.
Response delay
If the equipment does not respond, it is necessary to check whether the control circuit (such as relays, PLCS) has failed due to low temperature.
3. Record of abnormal phenomena
Common Questions:
The motor is humming but cannot start (possibly due to capacitor failure or phase sequence error).
Abnormal outlet air temperature (possibly due to an open circuit in the heating element or a malfunction of the temperature controller).
Third, performance verification after startup
Outlet air temperature and air volume
Test method:
When using an infrared thermometer to measure the temperature at the air outlet, it should reach more than 90% of the rated temperature (for example, if the rated temperature is 80℃, the actual temperature should be ≥72℃).
When using an anemometer to measure air volume, it should be ≥ 85% of the rated air volume.
Case: A certain hot air blower had an outlet air temperature of only 50℃ in an environment of -25℃. After inspection, it was found that the heating tube was aged. After replacement, it returned to normal.
2. Vibration and Noise
Vibration standard:
The vibration velocity of the motor should be ≤4.5mm/s (ISO 10816 standard).
Noise control
The noise should be ≤75dB (A) (measured at a distance of 1 meter from the equipment).
3. Long-term operational stability
Continuous monitoring
Let the equipment run continuously for one hour and observe whether there is overheating, leakage of electricity or abnormal noise.
Calibration of temperature control system
Check whether the temperature controller can accurately control the start and stop of the heating element to avoid overheating.
Fourth, suggestions for improving adaptability to low-temperature environments
Equipment selection:
Select a hot air blower specially designed for low temperatures (such as equipped with heating tapes, low-temperature lubricating oil, and cold-resistant cables).
Preheating measures:
Preheat the lubricating oil and battery before starting (such as by using a heating blanket or a vehicle preheater).
Maintenance cycle:
Shorten the maintenance cycle in low-temperature environments. It is recommended to conduct a comprehensive inspection every two weeks.
Fifth, Summary
After the hot air blower is used in a low-temperature environment, special attention should be paid to the starting performance of the three core components: the lubrication system, the electrical system, and the heating elements. Through systematic inspection and improvement measures, the failure rate caused by low temperatures can be effectively reduced and the service life of equipment can be prolonged. If there are still problems such as difficulty in starting up or performance degradation after inspection, it is recommended to contact the equipment manufacturer for professional maintenance or upgrade.
