Why the vacuum degree of miniature vacuum pump will drop?

Miniature vacuum pump VBH2005 used for a long time, the degree of vacuum, the flow rate decreased, it should be due to accumulation of dust inside the pump chamber. So customers use the pump extracted 1 ml of water, attempting to use water to clean the pump chamber dust, the result is not enough. The pump after repair processing, after disassembling all the components to dry, reassembled, everything returned to normal. This shows that micro-pump, micro-pump can not have water into the pump, or vacuum and flow will be significantly reduced, the appearance of the appearance of very weak suction. There are also miniature vacuum pump PCF series, miniature pump FAA series, intelligent vacuum pump ANB series, are not allowed to enter the pump of liquid water.