Vacuum generators

Almost any air pump that you have access to an inlet pipe for would probably do the trick. However, you failed to mention the size of vessel that you were trying to evacuate (even this tiny amount). If your pump is too small you may never overcome the leaks.

Mickey,

It really depends on the size of the application, i.e. what is the influx rate that you have to continuously evacuate? If there is no influx, how quickly do you have to draw down what volume?

Jet eductors, either air or water, might be appropriate if the application is large.

Oh, when you say a vacuum of 12.5 mBar, do you mean a gauge pressure of -12.5 mBar or an absolute pressure of 12.5 mBar? That does make an enormous difference, of course.

Walter.