Liquid ring compressor, the maximum exhaust pressure of a single stage is 0.3 MPa, and that of a double stage is 0.6 MPa. Double end-face mechanical seal, capable of compressing flammable and explosive gases, widely used in the chemical and petroleum industries for polyethylene, styrene, oxides, vinyl chloride monomer, sulfur dioxide, hydrogen sulfide, benzene, butylene, oxygen, etc.