Rotary displacement pump comprising scraper and guide of the scraper

A rotary displacement pump, comprising:

• a housing;
• a stator fixed in said housing;
• a rotor including a shaft portion and a radially protruding web having a configuration of and undulatory disk;
• a scraper having an engagement slot of predetermined radial height and predetermined axial width, the engagement slot engaging said protruding web of said rotor;
• a guide of said scraper, the guide generally having a configuration of a recessed plate and being at least one of directly or indirectly fixed in said housing, wherein the guide retains said scraper in a circumferential direction and allows said scraper a reciprocating movement in a substantially axial direction;
• said scraper, including
• a first groove having a predetermined depth and extending along its radially outer edge surface,
• and a second groove and a third groove each having a predetermined depth and extending in radial direction along one front edge surface and along another front edge surface, respectively, of said scraper,
• said first, second and third grooves being designed such that they accommodate a portion of said guide and allow said reciprocating movement of said scraper in said substantially axial direction;
• and said housing together with said stator and together with said scraper defining
• an inlet chamber, having an inlet port, of said pump,
• an outlet chamber, having an outlet port, of said pump, and
• a channel extending from said inlet chamber to said outlet chamber,
• said scraper forming a partition between said inlet chamber and said outlet chamber, and said web of said rotor being rotatable through said inlet chamber, said channel, said outlet chamber and said engagement slot of said scraper.