Metering pump made of plastic

1. A metering pump ( 1 ), made of plastic, comprising two rotors ( 10 ), which are coupled to one another via gearwheels ( 11 ) and are drivable in opposite directions and which are mounted in a pump housing ( 5 ) provided with a suction port ( 6 ) and an outlet port ( 7 ), wherein each of the rotors ( 10 ) has a rotor shaft ( 12 ), rotor shaft ends ( 15 ) of which are seated in walls ( 8 , 4 ) of the pump housing ( 5 ), and a rotor shaft axis (A), characterized in that each of the rotors ( 10 ) has two rotor blade walls ( 13 ), which are disposed diametrically on the rotor shaft ( 12 ) and onto peripheral ends of which are respectively molded partially cylindrical rotor blade shoes ( 14 ), wherein the rotor blade shoes ( 14 ) bear slidingly and sealingly against cylindrical inner wall regions of the pump housing ( 5 ), on the one hand, and against the rotor blade shafts ( 13 ) of the adjacent rotor ( 10 ), on the other hand, wherein the pump has an end wall ( 8 ) fixedly connected to the pump housing ( 5 ) and a detachable end wall ( 9 ), wherein the end wall ( 8 ) fixedly connected to the pump housing ( 5 ) defines both an open bearing sleeve ( 30 ) and an outwardly closed bearing sleeve ( 29 ), wherein at least one rotor shaft end ( 15 ) has a drive coupling part ( 16 ), which passes through the pump housing ( 5 ) and passes through the end wall fixedly connected to the pump housing ( 5 ), wherein both of the rotors ( 10 ) are identical and both thus have one of the drive coupling parts ( 16 ), and wherein one of the drive coupling parts ( 16 ) is seated in the open bearing sleeve ( 30 ) and the other drive coupling part ( 16 ) is seated in the outwardly closed bearing sleeve ( 29 ).

2. The metering pump as claimed in claim 1 , wherein the metering pump is disposable.

3. The metering pump as claimed in claim 1 , wherein one of the respective gearwheels ( 11 ) is molded in one piece onto one of the rotor shafts ( 12 ), and another of the respective gearwheels ( 11 ) is molded in one piece onto the other rotor shaft ( 12 ).

4. The metering pump ( 1 ) as claimed in claim 1 , characterized in that each of the rotor blade shoes ( 14 ) has on an outer face ( 21 ) at least one leading sealing scraping edge ( 23 ), which runs parallel to the rotor axis (A) and which is disposed close to, in a rotational direction, a leading end edge ( 22 ) of a respective rotor blade shoe ( 14 ).

5. The metering pump ( 1 ) as claimed in claim 4 , characterized in that on each rotor blade shoe ( 14 ) is respectively disposed a trailing sealing scraping edge ( 23 ), which runs parallel to the rotor axis (A) and is close to a trailing end edge ( 22 ) of the respective rotor blade shoe.

6. The metering pump ( 1 ) as claimed in claim 5 , characterized in that, in a region between each leading and trailing sealing scraping edge ( 23 ) and the rotor blade wall ( 13 ), a joint groove ( 25 ) is disposed on an inner face ( 24 ) of the rotor blade shoe ( 14 ), the inner face being on a side of the rotor blade shoe opposite the outer face.

7. The metering pump ( 1 ) as claimed in claim 1 , characterized in that into the open bearing sleeve ( 30 ) is molded, in one piece, at least one circumferential sealing lip ( 31 ).

8. The metering pump ( 1 ) as claimed in claim 1 , characterized in that on the two rotor blade walls ( 13 ) of each rotor ( 10 ), in end sides ( 26 ) remote from the gearwheels ( 11 ), is provided at least one sealing lip ( 27 ) for sealing contact against the detachable end wall ( 9 ) of the pump housing ( 5 ).

9. The metering pump ( 1 ) as claimed in claim 1 , characterized in that between the two rotor blade walls ( 13 ) of each rotor ( 10 ), on both sides of the rotor shaft ( 12 ), are arranged two parallel longitudinal stripping ribs ( 28 ).

10. The metering pump ( 1 ) as claimed in claim 1 , characterized in that the suction port ( 6 ) is provided with cutting and/or perforating opening means ( 17 ) and a mounting socket ( 3 ) with a flange ( 4 ), which mounting socket is configured to be welded onto a container wall.

11. The metering pump ( 1 ) as claimed in claim 1 , characterized in that the outlet port ( 7 ) is provided with a closing cap ( 18 ).

12. The metering pump ( 1 ) as claimed in claim 1 , characterized in that closed bearing bushes ( 19 ) for both rotors ( 10 ) are molded into the detachable end wall ( 9 ) of the pump housing ( 5 ).