Replacing the rotor of a screw compressor
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At present, the rotor end of one screw compressor is severely worn； The depth is about 20 mm. Spraying cannot fix it. Replace one female rotor. After returning and attempting to start the machine, the exhaust temperature increased ； The alarm value is reached in about 60 seconds. Cannot be used. Help: 1. Is it required to replace both the male and female rotors when replacing the rotor? 2. Is the condenser clogged? 3. Is there an issue of original wear and iron shavings in the system? 4. Is it caused by a high vacuum level?
Was the exhaust clearance checked after installing the new rotor? Is it within the specified range?
Replaced by the manufacturer; it wasn’t tested on a calibration bench, and high temperature was observed during testing after shipment.
Is the gap between the male and female rotors appropriate?
Replacing the rotor requires replacing both the male and female rotors simultaneously. Otherwise, uneven running-in can lead to excessive temperatures or wear-induced shavings, causing the rotor to lose balance or even become unusable. The gears of moving equipment and the compressor rotors must be supplied as a set when repairing or replacing parts.
It is not only replaced in pairs. The male and female teeth of the rotor are also aligned one by one. That’s good
If replacement is necessary, it must be done in pairs; rotors that are severely worn can cause excessive internal leakage, affecting the volume of air flow and the exhaust temperature. As for the issue of high exhaust temperature, for your unit, the rotor clearance is likely the main cause. In the case of a dry screw compressor, a high intake vacuum level can affect the pressure ratio and lead to higher exhaust temperatures. In the case of a wet screw compressor, the impact of inlet vacuum is much smaller; deviations within the normal operating range do not affect the exhaust temperature.
Repair of screw vacuum pumps: 1. After opening the pump, check whether there is wear on both rotors, as well as any contact wear on the pump body; it’s impossible for only one rotor to be worn – there must be contact wear and corrosion as well； 2. Whether the local coating cannot be repaired, or the entire coating cannot be repaired. 3. When adjusting the clearance, it is necessary to first fix the axial clearance, and then adjust the clearances between the two rotors (bottom clearance, concave surface clearance, convex surface clearance, top clearance); the clearance for large pumps is larger, while that for small pumps is relatively smaller. 4. If excessive heat is generated, check whether the cooling water is turned on; if the pump gets stuck even with the cooling water running, it means there is interference between the clearances of the two screws
1. It might be due to excessive clearance causing air leakage; by comparing the operating currents before and after, it can be seen that the current increases first when there is no change in the amount of air drawn in. This indicates that the spool is in a higher position, and possibly excessive wear on the end face of the rotor chamber is leading to air leaking from the outlet to the inlet, which in turn raises the temperature. 2. For oil-lubricated machines, the fuel injection volume and fuel injection temperature also need to be considered.