Various common problems of screw air compressor maintenance

Various common problems of screw air compressor maintenance

1.What are the maintenance methods for screw air compressor motors?

The operating environment of the motor should always be kept dry, the surface should be kept clean, and the air inlet should not accumulate dust, fibers and other debris. When the thermal protection and short-circuit protection of the motor continue to operate, check whether the fault comes from the motor or the overload, or because the protection device is set too low, the fault can be put into operation after the fault is cleared.

　　 When the motor bearing is running for 1500~2000h, grease should be added, and the bearing temperature should not exceed 120℃. When the temperature is lower than 70℃, the interval of adding grease can be appropriately extended. When filling oil, use a grease gun, first remove the grease plug on the oil drain pipe, add new grease until the original grease is discharged from the oil drain hole, wipe it with a rag, and tighten the oil plug after the oil is filled.

　　2. Description of daily maintenance and operation record table of screw air compressor

　　The daily maintenance and overhaul records of screw air compressors can be recorded regularly or irregularly, or recorded after maintenance. Accurate records are helpful for timely analysis and troubleshooting when the air compressor fails. The main content of the maintenance record includes inspection, cleaning, adjustment, supplementation, replacement and corresponding time. The maintenance records and operation records of the screw air compressor are shown in Table 1 and Table 2 respectively. (90% of practitioners pay attention to the WeChat public platform of Compressor Network)

　　3. What is the significance of maintenance for screw air compressors?

　　 Air compressors are in the best working condition if they are adequately maintained. Correct maintenance can increase the service life of the entire machine and greatly reduce the downtime of failure. The maintenance cycle of the screw air compressor is provided by the manufacturers with reference time. If the air compressor is installed in a clean and low temperature environment, the service cycle can be appropriately extended. The correct service cycle should be formulated according to the use environment of the air compressor .

　　 4. What are the daily maintenance items for screw air compressors?

　　 Daily maintenance items specifically include:

　　Check the coolant level and refill it in time;

　　 Replace the coolant;

　　Clean or replace the air filter element;

　　 Cooler after cleaning;

　　 clean oil cooler;

　　Clean the water separator;

　　 Replace the oil filter;

　　 Replace the oil and gas separator filter element;

　　 Check the leakage of hoses and all pipe joints, and eliminate the leaks in time;

　　Belt tightness check;

　　 Check all wire connections and tighten them in advance;

　　 Check the contacts of the AC contactor;

　　 Clean the dust on the surface of the motor suction port and the surface of the shell;

　　 Add grease to the main motor;

　　 Clean the motor and fan motor.

　　 5. Why must the air compressor switch regularly?

　　 When multiple air compressors are operated in parallel, they must be periodically switched. For air compressors in a humid working environment, switching operation is beneficial to drain the moisture in the lubricating oil; if the air compressor is out of service for a long time (such as one month left in the middle), it will cause adhesion particles on the oil filter element or the oil and gas separator filter element. Dry knots block the filter holes of the oil filter element or the filter element of the oil and gas separator, which shortens the service life of the filter element; the upper part of the air compressor rotor is not soaked in lubricating oil, and it will be shut down for a long time, which will cause this part of the rotor to contact with humid air and rust; Time downtime will also cause grease to accumulate in the air compressor pipeline or main engine, which will force the air compressor to be overhauled.

　　 6. What are the maintenance items for the new screw air compressor after it is put into operation?

The maintenance items after the new machine is put into operation 300h~500h: oil change and oil change filter, air filter cleaning, check for leaks, looseness, oil storage drum drain, motor body cleaning, belt tightness inspection and transmission device inspection, motor temperature L, current, host sound check.

Maintenance items after 2000h after the new machine is put into operation: check for leaks and looseness, oil storage drum drainage, body cleaning, oil and gas separator pressure difference, radiator cleaning, manual check of safety valve (draw rod), belt tightness and transmission device check, Check motor temperature rise, current, and host sound.

Maintenance items every 6 months or 4000h: oil change and oil change filter, air filter element cleaning, oil and gas separator filter element change (or pressure difference exceeding 0.08MPa), check for leaks and looseness, oil storage drum drain, motor body cleaning, Oil and gas separation pressure difference, radiator cleaning, manual inspection of safety valve (rod), motor and cooling fan bearings for lubrication, electrical insulation, contact status inspection, motor temperature rise, current, host sound inspection.

Maintenance items every 12 months or 8000h: oil change and oil change filter, air filter element cleaning, oil and gas separator filter element change (or pressure difference exceeding 0.08MPa), check for leaks and looseness, oil storage drum drain, motor body cleaning, Oil-gas separation pressure difference, radiator cleaning, motor and cooling fan bearing replacement lubricating oil, electrical insulation, contact condition inspection, safety protection device inspection, circulation system, control system aging inspection, safety valves, pressure gauges get the national production department calibration Inspection or replacement, pressure controller, solenoid valve, minimum pressure valve, temperature controller, intake valve, transmission device inspection or replacement, electrical main brake inspection, motor temperature rise, current, host sound inspection, safety device reliability .

　　The above maintenance items should be strictly implemented by the user. The maintenance time is different for each brand of air compressor. The most reasonable maintenance time is determined by the user after summing up the operating status of the air compressor.

　　7. What is the maintenance method for the air filter element of the screw compressor?

　　 The air filter is equipped with a differential pressure switch. When the set value of the differential pressure switch is reached, the differential pressure switch will act, or when the internal fixed time is zero, the LCD shows that the air filter is clogged, indicating that the air filter must be cleaned or replaced. Maintenance should be carried out after the air compressor is shut down and corresponding safety measures have been taken, as follows:

　　Open the end cap.

　　 Loosen the fixing bolts of the air filter element and take out the filter element.

　　 Check the blockage of the air filter, use compressed air to blow from the inside out to clean the dust, pay attention to the pressure of the compressed air does not exceed 0.3MPa.

　　 The air filter element should be replaced when it is damaged. To check whether the air filter element is damaged, you can use an electric lamp to place it in the air filter element and observe whether there is light exposed from the outside.

　　 When the surface of the filter element is stained with oil, replace the air filter element with a new one.

　　Clean or replace the filter element and cover the end cap.

　　 Check that the differential pressure switch equipped with the air filter is normal, and the preset value does not exceed 50kPa. (90% of practitioners pay attention to the WeChat public platform of Compressor Network)

　　 8. What is the maintenance method of the screw air compressor oil filter?

Whether the oil filter needs to be replaced can be judged by whether the oil filter differential pressure switch is activated or the oil filter timer time is zero. The new machine needs to cause insufficient oil intake after 500h of rotation for the first time, causing high exhaust temperature. Tripping, and the lack of oil will affect the bearing life. Maintenance should be carried out after the air compressor is shut down and corresponding safety measures have been taken, as follows:

　　 Unscrew the old filter with pliers.

　　 Clean the contact surface.

　　 Apply a thin oil film on the surface of the new filter seal.

　　Tighten the new filter by hand until the gasket is sealed; in particular, pay attention not to borrow other tools when the new filter is tightened, in case it is difficult to remove it during the next replacement.

　　 Check that the differential pressure switch equipped with the oil filter is installed properly. The preset value is 150kPa.

　　 9. What is the maintenance method of the oil and gas separator filter element of the screw air compressor?

　　Maintenance should be carried out after the air compressor is shut down and corresponding safety measures have been taken. Small air compressors mostly use rotary oil and gas separator filter elements, and the maintenance method is the same as that of oil filters; the built-in steps are as follows:

　　 Loosen the pipeline on the oil and gas barrel, and at the same time remove the pipeline from the outlet of the pressure maintenance valve (minimum pressure valve) to the aftercooler, remember to ensure that it can be reinstalled correctly.

　　 Loosen and take out the oil return pipe.

　　 Loosen the fastening bolts of the upper cover of the oil and gas barrel, and remove the upper cover of the oil.

　　 Take out the oil-air separator filter element and replace it with a new oil-air separator filter element and gasket.

　　 Follow the reverse steps to reassemble and tighten the bolts with a torque wrench.

　　 After the machine is turned on, re-tighten the bolts of the oil and gas barrel cover.

　　 Check that the pressure difference switch equipped with the oil and gas separator filter element on the oil and gas barrel is installed properly. The preset value is 100kPa.