The screw chiller is named after the use of a screw compressor. Its cooling power is higher than that of the scroll chiller, and it is mainly used in chemical plants, ink printing plants, automobile manufacturers or central air conditioning systems or other large industrial refrigeration.
The maintenance method is as follows:
1, disassembly
Before the screw compressor must be overhauled, if the cold storage equipment is possible, the spool valve will be unloaded to the “0†position, and the power will be shut off normally. The compressor can be disassembled by cutting off the piping connected to the compressor and discharging the refrigerant and lubricating oil in the compressor. Be careful to develop good habits when disassembling. Parts of different parts should be placed separately and the necessary assembly marks should be made.
(1) After removing the pipes, couplings, and anchor bolts connected to the compressor, lift the compressor to the workplace. Guangzhou cold storage equipment zui has a platform for operation.
(2) Remove the suction filter and suction check valve.
(3) Remove the energy indicator.
(4) Remove the locating pin, remove the suction end cap in parallel, and take out the oil piston and balance piston. Note that when the locating pin is taken, it can only be pulled out and cannot be pulled out. Be sure to remove the locating pin first, then remove all the bolts to prevent the weight of the suction end cap from acting on the locating pin and bend the locating pin.
(5) Remove the shaft cover and take out the shaft seal. Be careful not to touch the moving and stationary rings.
(6) Remove the locating pin and remove the vent cap.
(7) Remove the bearing gland, locknut, washer, thrust bearing, adjustment pad, etc. To remove the locknut from the cold storage equipment, use a special special tool and first open the lock piece of the lock washer. Mark them at any time and place them separately.
(8) After removing the positioning pin, remove the exhaust end seat.
(9) Use the special eye bolts to slowly and smoothly remove the active rotor, and do not collide with the body. At this time, the driven rotor rotates with it.
(10) Take out the driven rotor.
(11) Take out the slide valve.
2, check
Items examined include:
(1) Check the surface of the machine body and the surface of the slide valve for abnormal wear marks, and measure the inner surface size and roundness with an inner diameter dial gauge.
(2) Check the main and driven rotor end faces and the suction and exhaust end seats for wear marks.
(3) Check the outer and outer surfaces of the main and driven rotors and measure the outer diameter of the rotor with an outer diameter dial gauge.
(4) Measure the rotor main shaft diameter and the inner diameter of the main bearing hole, and 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 circuit conditions of the compressor.
(8) Check the energy indicator for damage or jamming.
(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
After inspection, repair or replace damaged parts. The details are as follows:
(1) For less severe wear and napping, it can be smoothed by the fitter with oil stone. The surface of the rotor journal and the shaft seal static ring of the cold storage equipment shall not have any defects such as rust and crack. After the surface of the main shaft is polished, the dimensions should be carefully measured and the main bearing adjusted accordingly.
(2) If the main bearing is severely worn, it exceeds the gap limit with the shaft and should be replaced. If the bearing alloy is cast, the coaxiality of the inner surface with the bearing hole must be ensured.
(3) The thrust bearing is damaged or the clearance is increased and must be replaced with a new one. The size of the vacuum clearance should be measured, and the bearing adjustment pad should be used as the basis.
(4) All gaskets and “O†rings must be replaced if damaged. The gasket can be machined by itself, but be careful not to break or crack near the bolt hole to avoid leakage. Gaskets should be made of high quality materials. The “O†ring should be made of a material suitable for the refrigerant.
(5) Clean the sealant on both ends of the body and the suction and exhaust end seat. Be careful not to scratch the surface.
4, assembly
Assembly work can be performed after each part has been inspected and repaired or replaced with damaged parts. When assembling, pay attention to the marks marked during disassembly, and do not confuse the parts. When assembling cold storage equipment , it is necessary to measure the assembly clearance of each part at any time. For parts with excessive clearance, adjust the clearance or replace the parts. See the gap table for assembly clearance.
(1) Clean all parts and blow dry with compressed air.
(2) Prepare the tools you need to use and clean them.
(3) Install the main bearing into the bearing hole as it is, and measure the inner diameter of the bearing so that the inner diameter meets the clearance requirements for mating with the rotor journal.
(4) Apply a sealant evenly on the contact surface of the suction end seat and the body.
(5) Place the suction end seat against the suction end of the machine body and string the part of the bolt to bear the weight. After pressing in the locating pin, tighten the bolts.
(6) Install the slide valve and its guide plate. The guide plate is first fixed by the positioning pin and can be fixed by bolts.
(7) Apply the same type of lubricating oil used in the main bearing hole and the inner hole of the suction end to the male and female rotors. The rear mounted rotor should be screwed in slowly and must not be forced into the body.
(8) The female and female rotors are pressed against the suction end seat, and the difference in size between the exhaust end surface of the rotor and the exhaust end surface of the body is measured. This value is the sum of the suction and exhaust gaps.
(9) Apply a sealant evenly on the surface of the exhaust end seat and the body.
(10) After the exhaust end seat is pressed against the discharge end of the body, press 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 washer and thrust bearing, and fix the thrust bearing inner spacer to the journal of the rotor with a round nut and a lock washer. The thrust bearings are installed in pairs and the mounting direction is noted.
(12) Install the rotor bearing gland and press the outer bearing of the thrust bearing against the body. Remove the connecting bolt of the exhaust end seat and the body, and pull the exhaust end seat together with the rotor to measure the gap between the exhaust end face of the rotor and the exhaust end seat. This gap is the exhaust end gap. If the gap is not reasonable, the thickness of the adjustment pad should be changed. Adjust the exhaust end clearance and assemble. After installation, the active rotor is driven in the actual running direction, and the rotation should be flexible and free of jamming.
(13) Install the exhaust end cap with the locating pin and attach the shims to the bolts.
(14) Install the shaft seal ring and apply the frozen oil on the surface of the moving ring and the apron.
(15) Install the static ring into the shaft seal gland and bolt it to the exhaust end seat. The preload of the shaft seal spring is adjusted by the thickness of the spacer. The static ring surface and the static ring apron are also coated with frozen oil.
(16) Install the oil piston and balance piston. Apply frozen oil to the assembly.
(17) Install the suction end seat on the positioning pin and attach the spacer to the bolt.
(18) Install the energy indicator. Note that the pointer corresponds to the position of the spool.
(19) Install the inhaled filter and check valve to the suction end seat. Ship the installed compressor to the unit. After finding the coaxiality, fix the compressor and the motor and connect them with a coupling.
5, after trial operation after maintenance
After the overhaul, the compressor was tested for air tightness and vacuum. The test run can be carried out after the test is passed. Mainly check the operation of the slide valve, whether the oil pressure of the oil pump is normal, and whether the noise and vibration during operation are normal. The car should be normal after the stop.
The maintenance method is as follows:
1, disassembly
Before the screw compressor must be overhauled, if the cold storage equipment is possible, the spool valve will be unloaded to the “0†position, and the power will be shut off normally. The compressor can be disassembled by cutting off the piping connected to the compressor and discharging the refrigerant and lubricating oil in the compressor. Be careful to develop good habits when disassembling. Parts of different parts should be placed separately and the necessary assembly marks should be made.
(1) After removing the pipes, couplings, and anchor bolts connected to the compressor, lift the compressor to the workplace. Guangzhou cold storage equipment zui has a platform for operation.
(2) Remove the suction filter and suction check valve.
(3) Remove the energy indicator.
(4) Remove the locating pin, remove the suction end cap in parallel, and take out the oil piston and balance piston. Note that when the locating pin is taken, it can only be pulled out and cannot be pulled out. Be sure to remove the locating pin first, then remove all the bolts to prevent the weight of the suction end cap from acting on the locating pin and bend the locating pin.
(5) Remove the shaft cover and take out the shaft seal. Be careful not to touch the moving and stationary rings.
(6) Remove the locating pin and remove the vent cap.
(7) Remove the bearing gland, locknut, washer, thrust bearing, adjustment pad, etc. To remove the locknut from the cold storage equipment, use a special special tool and first open the lock piece of the lock washer. Mark them at any time and place them separately.
(8) After removing the positioning pin, remove the exhaust end seat.
(9) Use the special eye bolts to slowly and smoothly remove the active rotor, and do not collide with the body. At this time, the driven rotor rotates with it.
(10) Take out the driven rotor.
(11) Take out the slide valve.
2, check
Items examined include:
(1) Check the surface of the machine body and the surface of the slide valve for abnormal wear marks, and measure the inner surface size and roundness with an inner diameter dial gauge.
(2) Check the main and driven rotor end faces and the suction and exhaust end seats for wear marks.
(3) Check the outer and outer surfaces of the main and driven rotors and measure the outer diameter of the rotor with an outer diameter dial gauge.
(4) Measure the rotor main shaft diameter and the inner diameter of the main bearing hole, and 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 circuit conditions of the compressor.
(8) Check the energy indicator for damage or jamming.
(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
After inspection, repair or replace damaged parts. The details are as follows:
(1) For less severe wear and napping, it can be smoothed by the fitter with oil stone. The surface of the rotor journal and the shaft seal static ring of the cold storage equipment shall not have any defects such as rust and crack. After the surface of the main shaft is polished, the dimensions should be carefully measured and the main bearing adjusted accordingly.
(2) If the main bearing is severely worn, it exceeds the gap limit with the shaft and should be replaced. If the bearing alloy is cast, the coaxiality of the inner surface with the bearing hole must be ensured.
(3) The thrust bearing is damaged or the clearance is increased and must be replaced with a new one. The size of the vacuum clearance should be measured, and the bearing adjustment pad should be used as the basis.
(4) All gaskets and “O†rings must be replaced if damaged. The gasket can be machined by itself, but be careful not to break or crack near the bolt hole to avoid leakage. Gaskets should be made of high quality materials. The “O†ring should be made of a material suitable for the refrigerant.
(5) Clean the sealant on both ends of the body and the suction and exhaust end seat. Be careful not to scratch the surface.
4, assembly
Assembly work can be performed after each part has been inspected and repaired or replaced with damaged parts. When assembling, pay attention to the marks marked during disassembly, and do not confuse the parts. When assembling cold storage equipment , it is necessary to measure the assembly clearance of each part at any time. For parts with excessive clearance, adjust the clearance or replace the parts. See the gap table for assembly clearance.
(1) Clean all parts and blow dry with compressed air.
(2) Prepare the tools you need to use and clean them.
(3) Install the main bearing into the bearing hole as it is, and measure the inner diameter of the bearing so that the inner diameter meets the clearance requirements for mating with the rotor journal.
(4) Apply a sealant evenly on the contact surface of the suction end seat and the body.
(5) Place the suction end seat against the suction end of the machine body and string the part of the bolt to bear the weight. After pressing in the locating pin, tighten the bolts.
(6) Install the slide valve and its guide plate. The guide plate is first fixed by the positioning pin and can be fixed by bolts.
(7) Apply the same type of lubricating oil used in the main bearing hole and the inner hole of the suction end to the male and female rotors. The rear mounted rotor should be screwed in slowly and must not be forced into the body.
(8) The female and female rotors are pressed against the suction end seat, and the difference in size between the exhaust end surface of the rotor and the exhaust end surface of the body is measured. This value is the sum of the suction and exhaust gaps.
(9) Apply a sealant evenly on the surface of the exhaust end seat and the body.
(10) After the exhaust end seat is pressed against the discharge end of the body, press 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 washer and thrust bearing, and fix the thrust bearing inner spacer to the journal of the rotor with a round nut and a lock washer. The thrust bearings are installed in pairs and the mounting direction is noted.
(12) Install the rotor bearing gland and press the outer bearing of the thrust bearing against the body. Remove the connecting bolt of the exhaust end seat and the body, and pull the exhaust end seat together with the rotor to measure the gap between the exhaust end face of the rotor and the exhaust end seat. This gap is the exhaust end gap. If the gap is not reasonable, the thickness of the adjustment pad should be changed. Adjust the exhaust end clearance and assemble. After installation, the active rotor is driven in the actual running direction, and the rotation should be flexible and free of jamming.
(13) Install the exhaust end cap with the locating pin and attach the shims to the bolts.
(14) Install the shaft seal ring and apply the frozen oil on the surface of the moving ring and the apron.
(15) Install the static ring into the shaft seal gland and bolt it to the exhaust end seat. The preload of the shaft seal spring is adjusted by the thickness of the spacer. The static ring surface and the static ring apron are also coated with frozen oil.
(16) Install the oil piston and balance piston. Apply frozen oil to the assembly.
(17) Install the suction end seat on the positioning pin and attach the spacer to the bolt.
(18) Install the energy indicator. Note that the pointer corresponds to the position of the spool.
(19) Install the inhaled filter and check valve to the suction end seat. Ship the installed compressor to the unit. After finding the coaxiality, fix the compressor and the motor and connect them with a coupling.
5, after trial operation after maintenance
After the overhaul, the compressor was tested for air tightness and vacuum. The test run can be carried out after the test is passed. Mainly check the operation of the slide valve, whether the oil pressure of the oil pump is normal, and whether the noise and vibration during operation are normal. The car should be normal after the stop.
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