Howden WRV, Руководство по обслуживанию, Страница: 45 / 64

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8.4 DISMANTLING 204, 255, 321 & 365 COMPRESSOR FOR MAJOR OVERHAUL (Continued)
Removing the Inlet End Cover (Continued)
Remove the rest of the set pins and carefully slide the inlet cover over the extended shaft of the male
rotor taking the ‘O’ ring seal with it (Figs. 60-61).
Removing the Rotors
In preparation for removing the rotors, unlock the thrust bearing lockwasher (Fig. 62) and remove the
bolts from the male and female rotors (Fig. 63).
A construction variation between the above compressors and the WRV163 & WRV204 compressor
is that thrust bearing housings are fitted in the WRVi255, WRVi321 & WRVi365 compressors.
Before removing the rotors, the thrust bearings must be withdrawn. It has been known that the thrust
housings, which have jacking holes provided for removal purposes, have been used as bearing
extractors by jacking out the housings and drawing the bearings off with them. This method of thrust
bearing removal is not recommended. The risk of the thrust housing flange being distorted, due to
the tight fit of the thrust bearing, is a possibility and would have a detrimental effect on the outlet end
clearance. The correct procedure is as follows:
1.
Remove the set screws securing the thrust housings to the main casing.
2. Fit three long studs and a jacking plate (See Tool Section 9.3).
3. Using a suitable hydraulic jack and cylinder between the jacking plate and the end of the
rotor shaft , apply pressure to the cylinder with the pump, press each rotor in turn out of the
thrust bearings and the casings (Fig. 64).
4. The rotors will require to be carefully supported as shown (Figs. 65-66) and the weight of the
various sizes of rotors is given in the following table (Fig. 67).
Fig. 62 Fig. 63