Principle of maintenance necessity of Roots blower:

罗茨风机凡使用过的零件，拆下来检查，不外乎以下几种情况：一是质量状况尚好，或者虽有磨损但不作修理也可以继续使用;二是存在缺陷，但经过修复仍然可以继续使用;三是有较大的缺陷，难以修复或修理价值不大，需要进行更换。

All used parts of Roots blower can be disassembled for inspection only in the following cases: first, the quality is good, or it can be used without repair even though it is worn; Second, there are defects, but they can still be used after repair; Third, there are large defects that are difficult to repair or have little repair value and need to be replaced.

检查过程中，该修换的零件应及时修换，否则影响鼓风机的检查质量。但如果对没有影响的部位盲目进行修理，或者将本来可以继续使用的零件提前更换，又会造成浪费，增加维修费用。因此，确定零件是否修换，总体上应遵循“有必要才修换”的原则。

During the inspection, the parts to be replaced should be repaired in time, otherwise the inspection quality of the blower will be affected. However, if the parts that are not affected are repaired blindly, or the parts that can be used continuously are replaced in advance, it will cause waste and increase maintenance costs. Therefore, the principle of "repair and replacement only when necessary" should be followed in determining whether to repair and replace parts.

罗茨风机维修可靠性原则：

Maintenance reliability principle of Roots blower:

有缺陷的零件需要修换，但究竟是修还是换，应遵循“能可靠使用”的原则。选择修理的零件，修理后应当恢复或基本上恢复原有的制造精度，满足整机对零件的技术要求。这些要求，通常包括零件的尺寸误差，表面粗糙度，形位公差和表面硬度等。一般说来，磨损不太严重的机壳墙板和转子等，经过修复大都可以照旧使用，此类缺陷通常选择修理;但轴承齿轮及油封等零件一旦损坏就难以修复，勉强使用往往带来更大的麻烦，因此检修时一般选择更换。

Defective parts need to be repaired and replaced, but whether to repair or replace them should follow the principle of "reliable use". After selecting the repaired parts, the original manufacturing accuracy shall be restored or basically restored to meet the technical requirements of the whole machine for the parts. These requirements usually include the dimensional error, surface roughness, geometric tolerance and surface hardness of parts. Generally speaking, the casing wallboard and rotor that are not too worn can be used as usual after repair, and such defects are usually repaired; However, once the bearing gear, oil seal and other parts are damaged, it is difficult to repair them. Reluctantly using them often brings more trouble. Therefore, they are generally replaced during maintenance.

罗茨风机维修经济性原则：

Economical principle of Roots blower maintenance:

可以修复的零件是否一定进行修复，而不选择更换，还应当对修理与更换的经济性进行比较。这种比较，不单是对零件的修理与重置费用进行比较，而是将修理费用和修理的使用时间进行权衡。

Whether the parts that can be repaired must be repaired rather than replaced, the economy of repair and replacement should also be compared. This comparison is not only to compare the repair and replacement costs of parts, but also to balance the repair costs and the service time of repair.