Vacuum pump lubricant recovery system returning lubricant from the air filter based on pressure measurements in the vacuum pump

A lubricant recovery system for a vacuum pump comprising:

• a reservoir to store a lubricant;
• a supply line connected to the reservoir, wherein the supply line can be connected to the vacuum pump to supply the lubricant to the vacuum pump;
• a return line connected to the reservoir to return a lubricant-air mixture from the vacuum pump to the reservoir by the return line;
• an air filter disposed inside the reservoir to separate lubricant from the lubricant-air mixture, wherein the air filter is connected to a scavenge line, wherein the scavenge line is connectable to a low-pressure region of the vacuum pump such that lubricant separated from the lubricant-air mixture by the air filter is drawn via the scavenge line into the vacuum pump;
• a valve is disposed in the scavenge line to selectively separate the air filter from the vacuum pump, wherein the valve is connected to a control unit;
• and
• a pressure gauge arranged at the low-pressure region of the vacuum pump or inside a vacuum apparatus connected to the vacuum pump in order to measure the pressure inside, wherein the control unit is configured to control the valve in dependence on the measured pressure.