Air Compressor Troubleshooting And Solutions
With the development of motor technology, compressor is regarded as “electrical”. “General purpose machines”; especially in coal chemical industry, machinery industry and other industries
For distance measurement applications, incremental and absolute encoders can be technically selected. The advantages of absolute encoder are accuracy and performance, but incremental encoder seems to be more economical and practical.
A normal compressor determines the safe operation of the whole air conditioner or refrigerator. For example, the piston compressor may burn out, the oil supply engine may fail, or the low pressure and air supply may be insufficient when it is working. If these problems occur, the device will not work properly.
The methods to quickly and accurately check and timely solve these problems affect the operating speed and product output of the compressor.
This document analyzes the common faults of the air conditioning compressor and provides solutions.
From the perspective of air flow, the possible fault is that the air pressure or compressed air temperature is too high. If the protective device does not work, the carbon deposit will ignite naturally and the pressure vessel may explode.
Another possible problem is that insufficient or too low air volume will affect production.
From the perspective of compressor structure, there are four types of problems: lubrication system problems, cooling water circuit problems, compressed air circuit problems, and mechanical failures.
- Burned compressor casing
When the piston compressor is working, the babbitt layer on the main bearing bush or connecting bearing bush may burn or peel off. This causes the temperature of the bearing bush to rise, producing high temperature and smoke, and melting the babbitt alloy.
-1.1 Lower oil temperature
In the past, people worried that the high oil temperature of the crank pin would cause combustion. The manual stipulates that the oil temperature cannot exceed 60 ℃ or 70 ℃, but there is no minimum limit.
However, lower than standard oil temperature will lead to the same failure. After the compressor shuts down in winter, the oil temperature of the compressor crankcase decreases. Therefore, the oil is very thick and the skin will burn when the machine is restarted. Therefore, it is better to use oil with lower consistency in winter.
-1.2 Crankshaft low fuel
If the hole below the oil level is blocked, the oil level will not be found. If the oil level in the crankcase is too low, the oil pumping unit will draw air intermittently.
Air resistance occurs to the drain pipe and the oil film of the bearing housing is damaged. After that, the compressor casing gradually became wet and may eventually burn off.
-1.3 Clearance between bearing bush and shaft
We used to measure the clearance between bearing bush and shaft by pressing the lead wire.
This method is applicable to measuring the main bearing housing, because the main bearing is fixed, the top cover is locked on the main bearing journal, and the main bearing journal does not move when the bolts are tightened.
However, this method is not applicable to the measurement of connecting bearing shells. When the connecting rod is tightened, the wire will be squeezed. If the link is tilted, the gap is not reflected correctly.
Therefore, depending on the size of the shaft, a dial indicator must be used to measure the clearance.
- Jet failure
-2.1 Refueling failure
The milk powder machine needs to be disassembled for inspection without refueling.
If the piston and pump body are excessively worn, the clearance increases and the pressure oil leaks, they should be cleaned, repaired and replaced.
-2.2 Oil suction failure
If the milk powder machine does not absorb oil, and the oil will not drop from the oil cap, it means that the oil suction valve is stuck, or the oil cap is improperly installed, and air will enter.
The oil suction valve of the milk powder pump must be cleaned and the rubber ring on the oil cap must be replaced.
-2.3 Insufficient oil supply
The reason why the oil supply of the milk powder machine is insufficient is that the system is not clean for a long time, which eventually leads to the blockage of the pipeline. Or the nut joint was not tightened after the overhaul, resulting in oil leakage. To solve this problem, the pipes must be cleaned and the joints tightened.
- Low voltage and high/low voltage
When the compressor pressure is low and the air volume is insufficient, if the compressed air duct cannot leak air, it is generally a problem of the compressor itself.
There are several problems that lead to insufficient air displacement of the compressor unit.
-3.1 Timely maintenance
First, check whether the compressor air displacement decreases after maintenance. How long did the service last? If the environment is bad, please check whether the power supply is blocked when the compressor operates for 2000 hours.
If the air filter is not seriously clogged, simply perform the dust removal procedure. If the stagnation is serious, a new propaganda base should be replaced.
In most cases, there is not much problem when the discharge of the compressor is reduced. The problem is that the customer was careless in maintenance and the air filter of the compressor was blocked. Replace with a new air filter, and the compressor can work normally.
In addition to the air filter, lubricants and other filter components are also important. Check whether the lubricant is within the standard range. If it is missing, please add it appropriately.
-3.2 Open the suction valve
Check the equipment when the compressor discharge decreases.
If your compressor has just been maintained and there is no problem with the three filters and dairy products, the technician should check the air valve of the compressor.
Remove the suction hose, open the compressor, and observe whether the opening of the suction valve is normal.
Generally speaking, the theoretical design life of the air valve is 100000 times. Each manufacturer’s brand and batch number are different, so the quality may be different. Therefore, the failure of the air inlet valve will reduce the air displacement of the crew.
When loading on the compressor, if the air inlet is not fully opened, it can be concluded that the reduction of air discharge is the air inlet fault, which should be maintained or replaced separately.
-3.3 Motor fault
For the exhaust volume of air inlet valve and equipment, it shall be considered whether the motor operates well after troubleshooting.
Due to local short circuit of motor coil or wear of bearing and motor shaft, the motor speed is lower than the rated speed, so the discharge capacity of compressor will be reduced. Check the engine coil and bearing, and test the exhaust capacity of the compressor after maintenance.
-3.4 Setting lower working pressure
If the operating pressure switch of the compressor is set lower than the standard value, it should be set higher.
The working pressure of compressor during factory test run shall be set according to customer requirements. It can be set as differential pressure when used by customers. For example, if the compressor starts to put the air pump into the air receiver and the pressure reaches 10 kg, the compressor will stop or unload. If the pressure reaches 7 kg, the compressor will restart. There is a pressure difference between them. This process can let the compressor rest to protect it.
Different compressor switches have different adjustment methods. One is that the pressure difference is fixed by the switch itself, and only the automatic stop pressure and maximum pressure are regulated. The switch is equipped with two buttons, which are adjusted by a slotted screwdriver. Both buttons must be adjusted in the same way. Otherwise they will move together, stop, stop, restart, and burn the appliance.
The other is to adjust the start pressure(low pressure) and stop pressure(high pressure).
- Compressor pressure adjustment
Turn the pressure regulating screw clockwise to increase the closing and opening pressure. Turn the pressure regulating screw counterclockwise to reduce the closing or opening pressure.
- Adjust the compressor differential pressure
When the differential pressure adjusting screw rotates clockwise, the closing pressure will not change and the opening pressure will increase. When the differential pressure adjusting screw is turned counterclockwise, the closing pressure will not change and the opening pressure will decrease.
If the working pressure is wrong due to the failure of the pressure switch, it is necessary to replace the pressure switch if it cannot be repaired.
-3.5 Environmental changes
The compressor is initially used in low altitude areas. If the compressor is moved to high altitude with other equipment when the factory is relocated, the environment will become humid and the emissions of the crew will be reduced.
The higher the altitude, the thinner the air, and the lower the output per unit time. If there is too much water in the air, compressed air will naturally contain a lot of water. In the subsequent treatment process, the waste gas will be reduced due to the participation of water vapor.
-3.6 Compressor drive belt loosening
In this case, the belt needs to be adjusted. If it is damaged, replace it with a new one.
Select the appropriate positioning method according to the matching of pulley and shaft.
The pulley is installed on the compressor cover shaft and the compressor motor. First, the pulley on the compression head is fixed and locked.
If it is loose, you can tighten it with a soft copper, aluminum or rubber hammer.
The seal can be assembled by pressing or heating and accumulation, and the heating temperature shall be controlled at 120-150 ℃.
If the tolerances of the tapered sleeve pulley are slightly combined, the inner bore of the tapered sleeve may be slightly extended and installed on the shaft.
The perpendicularity(accuracy less than 0.5mm) of the same reference plane as the two pulleys with a level ruler shall be less than 0.5mm.
The perpendicularity error is greater than 0.5mm. The installation foundation of compressor cover or compressor oil and gas tank can be adjusted with gasket to ensure that the vertical error of the same datum plane is not greater than 0.5mm.
The compressor cover or compressor drum mounting bolts must be tightened. According to the principle that the trademark is in the same position, install the belt on the pulley. With the small roller as the benchmark, use a straightedge or a laser measuring instrument to measure the plane straightness of the two pulleys, and the allowable error is less than 0.5mm.
Fasten the belt with the compressor motor adjusting screw. On the contrary, recheck the straightness of the two pulleys based on the large pulley, and the allowable error is less than 0.5mm. Finally, lock the adjusting screw and nut.
Replacing the belt is the same as adjusting the belt. You should not replace only one belt, but only pay attention to replacing the belt. Otherwise, the new belt will also be damaged due to the tension of the belt.
Do not splash lubricating oil on the belt or pulley to avoid belt slipping. The belt was checked 30 hours after the new machine was started. After the compressor belt is loose, it should be adjusted immediately.
- Compressor type problems and solutions
According to its floating principle and structure, there are several compressors, including piston compressor, rotary compressor, centrifugal compressor and axial compressor. In addition, different compressors may have different faults due to different applications and methods of use.
Refer to this document for more information on compressor types.
Common Types of Refrigeration Compressors: A Comprehensive Guide
Then, we will analyze the special problems of ordinary compressors, such as piston compressors, centrifugal compressors and screw compressors, and propose solutions.
-4.1 Troubleshooting of piston compressor
Common problems with piston compressors include:
-
The compressor works abnormally
-
Compressor starts and stops frequently
-
Hydraulic hammer of compressor
-
Too much noise during operation
-
Abnormal discharge pressure and temperature
-
Abnormal compressor oil pressure
-4.2 Troubleshooting of centrifugal compressor
Common faults of centrifugal compressor can be summarized as the following 11 points:
-
Abnormal vibration and noise
-
Bearing failure
-
Thrust bearing failure
-
The oil ring and sealing ring are damaged and the sealing is unstable
-
Unstable sealing system, exception
-
Invalid performance
-
Sharp increase
-
Wheel damage
-
leak
-
Insufficient flow and exhaust
-
Prime mover overload
-4.3 Troubleshooting of screw compressor
Screw compressor is a commercial compressor with 11 common faults.
-
Compressor does not work
-
The compressor cannot build pressure
-
Exhaust temperature too high or overheat protection
-
Frequent switching between full load and empty load operation
-
Empty operation failed; the pressure or safety valve cannot be maintained when it is empty
-
The air displacement or pressure is lower than the normal value
-
High oil content in tail gas and high oil consumption of compressor
-
Oil spill
-
Abnormal unit sound
-
overload protection
-
The host is overloaded or blocked during startup. Main contactor acts automatically
Generally speaking, there are many kinds of compressors, but due to the floating working environment and operation method, there may be floating problems. Another solution is required at this time. But the structure principle is almost the same, and the basic operation method is also similar. Therefore, the clothing problem of floating compressor can be referred to in reality.