Sir/Ma'am,
I have a vacuum pump (model. Recently, I have been facing the issue of vacuum pump oil leaking into the vacuum bagging pipe. I am attaching the photos below. Kindly help me understand and solve this issue.

Bhanu

Bingo ^ 

These older style pumps don't have a one-way valve on the inlet, so if you don't shut it off afterwards then you essentially 'infuse' the oil out of the pump.

The new pumps from EC have a one way valve built in so this isn't an issue.