Air intake and exhaust filtering system for suction-type sewer scavenger

The invention belongs to the technical field of special vehicles for environmental sanitation cleaning, and particularly relates to an air intake and exhaust filtering system for a suction-type sewerscavenger. The air intake and exhaust filtering system is characterized by comprising a water and air separator, a cross valve, a vacuum dirt suction pump, an oil and air primary separator, an oil andair secondary separator and an anti-back flowing protecting device, wherein the water and air separator is connected with the cross valve; the cross valve is provided with a suction shift and a discharge shift; the oil and air are separated twice; the vacuum dirt suction pump is a pump unit which is formed by coaxially connecting a pump I and a pump II. Compared with the prior art, the air intakeand exhaust filtering system has the beneficial effects that (1) by adopting the double-vacuum pump axial connecting type pump unit, the working efficiency is improved by one time; (2) when the pressure of air in the tank exce