Adopting oil-free piston pump. Clean-without pollution of oil and smoke. Convenient-no need add oil to maintain daily. Safe-no plus pressure during using. No flow backwards pressure when the machine stops, so the liquid won’t flow backwards. 7A-23B type of electric suction apparatus adopts completely plastic panel design, which makes it more fancy and fashionable. The device of intercepting oil for circumfluence can reduce the oil pollution. Easy to carry, low noise, high negative pressure and large flux. It can be widely applied in the surgical operations, which needs to absorb phlegm etc thick liquids and other occasions, which need negative pressure suction.