Multistage ejector assembly

A multistage ejector assembly of the type including a casing body and a multistage ejector assembly into said casing body to produce a suction force of vacuum pressure at a suction port by the action of pressurized air supplied to said multistage ejector, wherein said multistage ejector assembly comprises:

• said casing body being channel-shape in cross-section having a bottom wall internally providing an axial through hole to receive said multistage ejector structure, said casing body having a channel-like groove formed therein by a pair of parallel side walls extending from said bottom wall,
• said multistage ejector including a nozzle body connected to a supply of pressurized air and having a spout hole jetting pressurized air therefrom, and a multistage ejector structure which is separated from the nozzle body and which includes an ejector body which is molded a one piece integral structure comprising a plurality of diffuser-nozzles including a diffuser of a final stage, said diffuser nozzles being located in an axially aligned relation with said spout hole of said nozzle body and being connected through a diameter portion having a suction opening, wherein said ejector body has flanges respectively formed around said diffuser-nozzles and said diffuser of the final stage and wherein said ejector structure includes three seal members located between said ejector body and said casing;
• said nozzle body and said multistage ejector being hermetically sealed in said axial through hole on said casing body to define therein a plurality of vacuum generating chambers by said flanges, said vacuum generating chambers being communicated with said groove through a plurality of suction passages provided on said casing body, and
• a vacuum chamber provided with said groove of said casing body between said suction port and said suction passes from said vacuum generating chambers.