Roller bearings
BITZER screw compressors are equipped with fatigue resistant bearings. The bearings are designed for more than 100000 h operation in the central area of the application limits. For this reason, it is generally not necessary to replace them during normal operation. However, due to deviations from normal operation, for example due to lack of oil, oil dilution due to wet operation, insufficient suction gas superheat or thermal overload, it may be necessary to replace the bearings.
Checking the roller bearings
Bearing wear is checked by a sound evaluation. Slight bearing damage and slight wear cannot be determined analytically. Defective bearings, however, are easily audible due to a significantly increased noise emission. If this is the case, the bearings must be replaced as quickly as possible.
At bearing change the rotors, the housing and the discharge flange should also be checked visually.
In case of severe scores or distinct signs of wear, overhaul or replace the entire compressor!
For a preventive maintenance the replacement intervals of the bearings are also listed in the table. In case of a normal and fault free operation, however, the full life span potential of the bearings is not utilised.
Inspection and replacement intervals for normal operation (definition Normal operation) and for predominant operation at high condensing temperatures tc>50 °C
Refrigerant | Air conditioning | Medium temperature | |||
|---|---|---|---|---|---|
Inspection | Replacement | Replacement | Inspection | Replacement | |
R134a / R450A / R513A / R1234yf / R1234ze | 10000 h | 50000 h | 40000 h | 10000 h | 50000 h |
R22 / R407C / R290 / R448A / R449A / R454C / R455A | 10000 h | 40000 h | 30000 h | 10000 h | 40000 h |
R404A / R507A | 10000 h | 40000 h | |||