Connect fittings of appropriate size to the suction port of the vacuum pump (if the size of the suction port on the pump is just right, those three fittings are not needed), connect the interface, and then turn on the switch to start pumping ("-" means opening to start pumping Air, "o" means turn off and stop pumping).
Air pumps are mainly divided into electric air pumps, manual air pumps, and foot pumps. Electric air pump. An air pump powered by electricity uses electricity to continuously compress air to generate air pressure. Mainly used for gas pumping, sewage treatment, electroplating blasting, biogas tank aeration, tunnel ventilation, etc.