Description of screw compressor
The screw refrigeration compressor is a volumetric compressor, which compresses the gas by the change of the volume. The compressor uses two screws with helical grooves placed in the body to mesh and rotate, and it is connected with the inner wall of the body and the suction and exhaust. The cooperation of the inner wall of the end seat causes the change of the volume between the teeth, so as to complete the process of gas inhalation, compression and discharge.
Features of screw refrigeration compressor:
Simple structure, small number of parts, high strength and wear resistance of rotor bearings;
Forced gas delivery, that is, the exhaust volume is hardly affected by the exhaust pressure;
It can still maintain high efficiency in a wide range of working conditions;
The sliding valve adjustment is adopted, which can realize the stepless adjustment of energy and is not sensitive to the liquid inflow.
Internal structure of screw compressor
Screw air compressors are now advertised for use in refrigeration and HVAC. This article summarizes common faults and causes, hoping to help you.
1. The exhaust pressure of the screw air compressor is too high
1. The inlet water temperature of the condenser of the air compressor is too high or the flow rate is insufficient;
2. There is air or non-condensable gas in the system;
3. Serious scaling in the copper tube of the condenser;
4. Excessive refrigerant charge;
5. The intake valve on the condenser is not fully opened;
6. The suction pressure is higher than normal;
7. Water pump failure.
2, the screw air compressor exhaust pressure is too low will cause failure
1. The water flow through the condenser is too large;
2. The inlet water temperature of the condenser is too low;
3. A large amount of liquid refrigerant enters the compressor;
4. Insufficient refrigerant charge;
5. The suction pressure is lower than the standard.
3. The suction pressure of the screw air compressor is too high
1. Excessive charging of refrigerant;
2. When the screw air compressor is at full load, a large amount of liquid refrigerant flows into the compressor;
4, the suction pressure is too low
1. The refrigerant liquid outlet valve of the condenser is not fully opened;
2. The refrigerant filter is blocked;
3. Improper adjustment or failure of expansion valve;
4. Insufficient refrigerant charge;
5. Excess lubricating oil circulates in the refrigeration system;
6. The inlet water temperature of the evaporator is too low;
7. The amount of water passing through the evaporator is insufficient.
5. The compressor shuts down due to high pressure protection
1. The amount of water passing through the condenser is insufficient;
2. The copper tube of the condenser is blocked;
3. Excessive charging of refrigerant;
4. The setting value of high voltage protection is incorrect,
6. The screw air compressor stops due to the overload of the main motor
1. The voltage is too high or too low and the phase is unbalanced;
2. Exhaust pressure is too high;
3. The return water temperature is too high;
4. Failure of overloaded originals;
5. The main motor or terminal is short-circuited.
7. The compressor shuts down due to the temperature protection of the main motor
1. The voltage is too high or too low;
2. Exhaust pressure is too high;
3. The cold water return temperature is too high;
4. Insufficient refrigerant charge;
5. The temperature protection device is faulty;
6. The condenser gas inlet valve is closed.
8. The compressor shuts down due to low pressure protection
1. The refrigerant filter is blocked;
2. Expansion valve failure;
3. Insufficient refrigerant charge;
4. The condenser liquid outlet valve of the screw air compressor is not opened.
9, the compressor can not run
1. The overload protection is disconnected or the control line fuse is blown;
2. The control circuit is in poor contact;
3. The compressor relay coil is burned out;
4. Phase error.
10. Uninstalling the system does not work
1. Thermostat failure;
2. The unloading solenoid valve is faulty;
3. The unloading mechanism is damaged.
11. The startup load is heavy or cannot be started
1. The exhaust pressure of the screw air compressor is too high;
2. Exhaust check valve leaks;
3. The energy adjustment is not at the zero position;
4. There is too much oil or liquid in the machine;
5. Partial mechanical wear;
6. The pressure relay is faulty or the adjustment pressure is too low.
12. The screw air compressor vibrates continuously after starting
1. Tighten the anchor bolts of the unit;
2. The axis of the compressor and the motor is misaligned and eccentric;
3. The compressor rotor is unbalanced;
4. The unit and the pipeline have the same vibration frequency and resonance;
5. Poor balance of the coupling.
13. After the screw air compressor starts, it vibrates for a short time and then stabilizes:
1. Inhalation of excess lubricating oil or liquid;
2. The compressor accumulates oil and causes liquid shock.
14. There is abnormal noise in the operation of the air compressor
1. There is a foreign body in the rotor;
2. The thrust bearing is worn and broken;
3. The sliding bearing is worn, the rotor and the casing are worn;
4. The running connector (coupling, etc.) is loose;
5. Oil pump cavitation.
15. Compressor automatically stops for no reason
1. High voltage relay action;
2. Oil temperature relay action;
3, fine filter differential pressure relay action;
4. Control circuit failure;
5. Overload.
16. Insufficient refrigeration capacity of screw air compressor
1. Insufficient fuel injection;
2. The slide valve is not in the correct position;
3. The inhalation resistance is too large;
4. The machine wear clearance is too large;
5. The energy regulating device is faulty.
17, the energy adjustment mechanism does not work or does not work
1. The four-way valve cannot be used, and the control circuit is faulty;
2. The oil pipeline or joint is blocked;
3. The oil piston clearance is too large;
4. The slide valve or oil piston is stuck;
5. The oil pressure is not high
18. Exhaust temperature or oil temperature is too high
1. The compression ratio is too large;
2. The heat transfer effect of the oil cooler is not good;
3. Inhalation of superheated gas;
4. Insufficient fuel injection.
19 the compressor body temperature is high
1. The friction part of the body is hot;
2. The inhaled gas is overheated;
3. The compression ratio is too high;
4. The heat transfer effect of the oil cooler is poor.
20. High fuel consumption
1. Too much oil in one oil separation;
2. The secondary oil separator has oil return.
21. Oil pressure is not high
1. Improper adjustment of the oil pressure regulating valve;
2. Excessive fuel injection;
3. The amount of oil is too large or too small;
4. Internal oil leakage;
5. The rotor is worn and the efficiency of the oil pump is reduced;
6. The oil circuit is not smooth (the fine filter is blocked);
7. The amount of oil is insufficient or the oil quality is poor.
22. Oil level rises
1. The refrigerant is dissolved in the oil;
2. Enter the liquid refrigerant.
23. The screw air compressor keeps reversing during shutdown
1. The suction check valve is stuck and the valve is not closed;
2. Insufficient elasticity of the suction check valve spring.