Eschmann VP12-S High Vacuum Suction Unit
This works with a motor which operates a suction pump which evacuates a bottle, and it is from this bottle that your suction tube will lead to the patient.
There will be a system of regulating the vacuum by allowing air to be drawn in from the room, and a pressure gauge so that you can see what you are getting. Some operate with a reciprocating motor moving a diaphragm with in and out valves, and some operated from a rotary vane motor.
One of the best is made by Eschmann called a Matburn VP12s (there are other models).These are the Rolls Royce of suction units.
They have a large motor driving the pump. They are large but very quiet. They have an oil reservoir, this is filled with 200 mls of vacuum oil and needs to be checked every 1000 hours of use, which for a sucker that is only on for short spells, is a long time.
If the oil level drops below 10ml the unit will not operate as well as it should.