1. Maintenance Preparation
A. Coordinate the machine maintenance sequence with the production department to ensure orderly production and the quality of inventory products;
B. Ensure on-site hoisting equipment is in good working order, protective facilities are in place, and monitoring personnel are in place;
C. Drain the refrigerant oil from the compressor body into an empty oil tank, close all inlet and outlet valves, and after the internal pressure of the compressor body drops to negative pressure, vent it to the atmosphere;
D. Support suspended pipes to prevent collisions;
E. Unload the slide valve to the 0 position;
F. Confirm that all lifting equipment (including steel cables, lifting lugs, lifting rings, etc.) is safe and usable.
G. Prepare a clean site for maintenance work;
H. Disconnect the main unit power supply;
2. Precautions during compressor overhaul:
A. Unload the slide valve to the 0 position;
B. Some parts on the rotor assembly may look similar, but they cannot be mixed. Mark them carefully during disassembly, distinguishing between the male and female rotors, and the suction and discharge ends;
C. Replace damaged O-rings, retaining washers, and round nuts during reassembly;
D. Components between different bearings cannot be interchanged;
E. Always apply oil when replacing new O-rings;
3. Disassembly:
A. After removing the coupling guard, suction filter, suction check valve, oil pipes, coupling, and compressor foundation bolts from the compressor unit, hoist the compressor to the maintenance work site;
B. Remove the energy level indicator cover and electrical components, and place the oil tank under the oil cylinder;
C. After removing the locating pin, remove the suction end cover parallel to the cylinder and remove the oil piston; D. After removing the locating pin, remove the intake end seat;
E. Remove the shaft seal cover and take out the shaft seal stationary ring and rotating ring assembly;
F. After removing the locating pin, remove the exhaust end cover;
G. Loosen the round nut and remove the thrust bearing, paying special attention to making the assembly marks;
H. Remove the drive rotor. Using the special eye bolts, gently and evenly remove the drive rotor. At this point, the driven rotor will be attached and rotating; the drive rotor needs to be rotated;
I. Remove the driven rotor using the eye bolts;
J. After removing the locating pin, remove the exhaust end seat.
K. Remove the slide valve
4. Inspection
A. The rotor shaft surface and shaft seal components must be free of rust, cracks, and other defects. Check for wear and scratches on the machine body and other parts.
B. Replace the main bearings and thrust bearings.
C. Replace the gaskets and O-rings with new ones.
D. Clean the original sealant from both ends of the machine body and the intake and exhaust end surfaces.
5. Assembly
A. Each part should be inspected before assembly. Repair or replace any damaged parts. Pay close attention to the assembly position marks made during disassembly to avoid misalignment.
B. Clean all parts thoroughly and dry them with compressed air.
C. Install each main bearing into its original position in the intake and exhaust end bearing holes, and measure the bearing inner diameter to ensure it meets the clearance requirements for the rotor journal.
D. Place the intake end seat on the intake end of the machine body and press in the locating pin. E. When applying sealant, ensure even application.
F. Place the suction end seat on the machine body's suction end, press in the locating pin, and secure with bolts.
G. Apply the same brand of refrigerant oil as used during normal operation to the main bearing bore at the suction end and the inner bore of the machine body. Then install the male and female rotors. The rotor installed later should be slowly screwed in; do not force it into the machine body. The end faces of both rotors should be firmly against the suction end seat. At this point, measure the dimension between the rotor exhaust end face and the exhaust end seat.
G. Apply sealant to the surface where the exhaust end seat and the machine body meet, ensuring even application.
H. Place the exhaust end seat on the machine body's discharge end, position it with the locating pin, and secure with bolts. When installing the exhaust end seat, pay attention to the inner bore of the main bearing; do not scratch the main bearing.
I. Insert the adjusting shims and thrust bearing, and secure the inner race of the thrust bearing to the rotor journal with a round nut. Pay attention to the direction of the thrust bearing.
J. Install the bearing pressure ring. After assembly, gently rotate the drive rotor in the actual operating direction; it should rotate freely. If the discharge end clearance is unreasonable, adjust the shim thickness.
K. After positioning the discharge end cover with the locating pin, secure it with bolts.
L. Install the shaft seal and rotating ring, and apply refrigerant oil to the friction surface of the rotating ring.
M. Install the shaft seal cover and stationary ring.
N. Install the oil piston and suction end cover.
O. Install the energy indicator, ensuring the pointer corresponds to the slide valve position.
P. Hoist the assembled compressor into the unit, align it with the motor, and install the coupling after coaxial alignment.
6. Post-overhaul test run
The overhauled compressor needs to undergo a test run. Only after a normal test run can it be put into formal operation. Perform a no-load test run, adjusting the installation status of each component during the test run. The trial run includes:
A. Unit leak test;
B. Oil pump oil pressure test;
C. Slide valve operation test;
D. Before installing the coupling, check the motor rotation direction. After connecting the coupling, the compressor should rotate easily without jamming.
G. With the slide valve in the 0 position, start the compressor and carefully check vibration, oil temperature, oil pressure, and noise.
H. With the slide valve in the 0 position, stop the machine. After stopping, the compressor should rotate easily.
F. Vacuum test: The absolute pressure should be below 5.332 kPa.
I. Replace the lubricating oil after compressor maintenance.
J. After the trial run and before formal operation, all lubricating oil in the unit should be replaced.
K. Oil filling: Use vacuum oil filling.