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Screw Compressor Of Cold Storage Maintenance Methods

Apr 07, 2020

Screw Compressor of Cold Storage Maintenance Methods


First, the disassembly method of the cold storage screw compressor


Before the cold storage screw compressor must be overhauled, if possible, unload the slide valve to the "0" position, shut down normally, and cut off the power supply. The pipeline connected to the compressor should be cut off and the refrigerant and lubricating oil in the compressor should be discharged before the compressor can be disassembled. Pay attention to good habits when disassembling, parts of different parts should be placed separately, and make necessary assembly marks.


1. After removing the pipeline, coupling and anchor bolts connected to the compressor, hoist the compressor to the workplace. There is an operating platform.


2. Remove the suction filter and suction check valve.


3. Remove the energy indicator.


4. Remove the positioning pin, remove the suction end cap in parallel, and remove the oil piston and balance piston. Note that the positioning pin can only be pulled out and cannot be smashed out. Be sure to remove the positioning pin first and then remove all bolts to prevent the weight of the suction end cap from acting on the positioning pin and bending the positioning pin.


5. Remove the shaft seal cover and take out the shaft seal. Be careful not to hurt the moving and static rings.


6. Remove the positioning pin and remove the exhaust cover.


7. Remove the bearing gland, locknut, washer, thrust bearing, adjustment pad, etc. To remove the locknut, use the special tool provided and start the lock piece of the lock washer first. Mark them at any time and place them separately.


8. After removing the positioning pin, remove the exhaust end seat.


9. Use special eye bolts to take out the active rotor slowly and steadily, do not collide with the body. At this time, the driven rotor rotates accordingly.


10. Take out the driven rotor.


11. Take out the spool.


Second, the inspection items of the cold storage screw compressor


1. Check the inner surface of the machine body and the surface of the slide valve for abnormal wear marks, and measure the size and roundness of the inner surface with a dial indicator.


2. Check whether there are any wear marks on the end faces of the main and driven rotors and the suction and exhaust end seats.


3. Check the wear of the outer diameter and tooth surface of the main and driven rotors, and measure the outer diameter of the rotor with an outer diameter dial gauge.


4. Measure the rotor spindle diameter and the inner diameter of the main bearing hole to check the main bearing wear.


5. Check the wear of the shaft seal.


6. Check the deformation and damage of all "o" rings and springs.


7. Check all internal oil circuits of the compressor.


8. Check whether the energy indicator is damaged or stuck.


9. Check the oil piston and balance piston for abnormal wear.


10. Check the transmission core or diaphragm of the coupling for damage.


3. Repair method of cold storage screw compressor


After inspection, repair or replace damaged parts. The details are as follows:


1. For less serious abrasion and roughening, it can be smoothed by fitter with oil stone. The surface of the rotor journal and the dynamic and static ring of the shaft seal must not have any defects such as corrosion and cracks. After the spindle neck surface is polished, the size should be carefully measured, and the main bearing should be adjusted based on this.


2. If the main bearing wears seriously and exceeds the clearance limit matched with the shaft, it should be replaced. If the bearing alloy is cast, the coaxiality of the inner surface and the bearing hole must be ensured.


3. If the thrust bearing is damaged or the clearance increases, a new one must be replaced. And the vacuum clearance should be measured, based on this, the bearing adjustment pad should be used.


4. All gaskets and "O" rings must be replaced if damaged. The gasket can be processed by yourself, but be careful not to break or crack near the bolt hole to avoid leakage. The gasket should be made of high-quality materials. "O" ring should be selected to adapt to the refrigerant material.


5. Clean the sealant on both sides of the machine body and the plane of the suction and exhaust end seats. Be careful not to scratch the surface.


Fourth, the cold storage screw compressor assembly details


After inspecting each part, and repairing or replacing damaged parts, assembly work can be carried out. When assembling, pay attention to the marks noted during disassembly, and do not confuse parts. When assembling, it is necessary to measure the assembly gap of each part at any time. For the part where the gap exceeds the standard, the gap must be adjusted or parts should be replaced. Assembly clearance see clearance table


1. Clean all parts and blow dry with compressed air.


2. Prepare and clean the necessary tools.


3. Put the main bearing into the bearing hole in situ, and measure the inner diameter of the bearing so that the inner diameter meets the clearance requirements of the rotor journal.


4. Evenly apply sealant on the surface of the suction end seat and the body.


5. Put the suction end seat against the suction end of the machine body, and insert some bolts to bear the weight. After pressing the positioning pin, tighten the bolt.


6. Install the slide valve and its guide bracket. The guide pallet can be fixed with bolts after being positioned by the positioning pin.


7. Apply the same type of lubricating oil used for the main bearing hole of the suction end and the inner hole of the machine body to the operation, and install it into the male and female rotors. The back-mounted rotor should be slowly screwed in, and cannot be forced into the body.


8. Place the female and male rotors close to the suction end seat, and measure the difference in size between the exhaust end face of the rotor and the exhaust end face of the machine body.


9. Evenly apply sealant on the surface of the exhaust end seat and the body.


10. Put the exhaust end seat against the discharge end of the machine body, press in the positioning pin, and tighten the bolt. Pay attention to the inner hole of the main bearing when installing the exhaust end seat, and do not damage the main bearing.


11. Install the adjusting shim, thrust bearing, and fix the inner spacer of the thrust bearing on the rotor journal with a round nut and anti-lock lock pad. Thrust bearings are installed in pairs, and pay attention to the installation direction.


12. Install the rotor bearing gland and press the outer spacer of the thrust bearing against the machine body. Remove the connecting bolts between the exhaust end seat and the body, pull the exhaust end seat together with the rotor, and measure the gap between the exhaust end face of the rotor and the exhaust end seat. This gap is the exhaust end clearance. If the gap is unreasonable, the thickness of the adjustment pad should be changed. Assemble after adjusting the clearance of exhaust end. After installation, move the active rotor according to the actual operating steering wheel. The rotation should be flexible and free of jamming.


13. Install the positioning pin on the exhaust end cover, and fix it with bolts by adding gaskets.


14. Install the shaft seal moving ring and apply freezing oil on the surface of the moving ring and the rubber ring.


15. Put the static ring into the shaft seal gland, and add gasket to the exhaust end seat. Adjust the pretension of the shaft seal spring by the thickness of the gasket. The surface of the static ring and the static ring aprons are also coated with freezing oil.


16. Install oil piston and balance piston. Apply freezing oil during assembly.


17. Install the positioning pin on the suction end seat, and add a washer to fix it with bolts.


18. Install the energy indicator, pay attention to the pointer corresponding to the position of the spool.


19. Install the repaired suction filter and check valve on the suction end seat. Transport the assembled compressor to the unit. After finding the coaxiality, fix the compressor and motor, and connect them with a coupling.