Scroll pump and method of assembling same

1. A method of assembling a scroll pump, the scroll pump comprising a housing; a drive shaft having an eccentric shaft portion; first bearing means for supporting the drive shaft for rotation; second bearing means for supporting an orbiting scroll on the eccentric shaft portion so that during use rotation of the shaft imparts an orbiting motion to the orbiting scroll which co-operates with a second scroll for pumping fluid along a fluid flow path between an inlet and outlet of the pump; and a bellows arrangement for isolating the first bearing means and the second bearing means from the fluid flow path and for providing relative rotational location of the orbiting scroll with respect of the second scroll; comprising the steps carried out sequentially of:

mounting the first bearing means and the drive shaft for rotation relative to the housing;

fastening a first flange portion of the bellows arrangement relative to the housing;

fastening the orbiting scroll to a second flange portion of the bellows arrangement; and

fixing the second scroll relative to the housing for co-operation with the orbiting scroll.

2. The method as claimed in claim 1 , further comprising the step of fastening the second bearing means relative to the orbiting scroll and mounting the second bearing means to the eccentric shaft portion prior to the step of fastening the orbiting scroll to the bellows arrangement.

3. The method as claimed in claim 1 , further comprising the step of fastening the orbiting scroll to the second flange portion of the bellows arrangement with at least one fastener which is inserted through a bore in the orbiting scroll.

4. The method as claimed in claim 3 , further comprising the step of inserting the fastener through the bore so as to be substantially flush with a surface of the orbiting scroll.

5. The method as claimed in claim 1 , further comprising the step of fastening a counter-weight for the orbiting scroll to the drive shaft with an axially extending fastener.

6. The method as claimed in claim 5 , wherein the step of fastening the counter-weight to the drive shaft takes place subsequently to the step of fastening the first flange portion of the bellows arrangement relative to the housing.

7. A scroll pump comprising:

a housing;

a drive shaft having an eccentric shaft portion;

first bearing means supporting the drive shaft for rotation;

second bearing means supporting an orbiting scroll on the eccentric shaft portion so that during use, rotation of the shaft imparts an orbiting motion to the orbiting scroll which co-operates with a second scroll for pumping fluid along a fluid flow path between an inlet and outlet of the pump; and

a bellows arrangement isolating the first bearing means and the second bearing means from the fluid flow path; wherein the bellows arrangement has a first flange portion fastened relative to the housing and a second flange portion fastened to the orbiting scroll with at least one fastener which extends through a through-bore in the orbiting scroll and engages with the second flange portion.

8. The scroll pump as claimed in claim 7 , wherein the through-bore extends through a surface of the orbiting scroll defining the fluid flow path.

9. The scroll pump as claimed in claim 7 , wherein the fastener is at a radially outer portion of the orbiting scroll.

10. The scroll pump as claimed in claim 7 , wherein the through-bore has a counter-sunk recess so that when the fastener is inserted through the through-bore, a head of the fastener is received in the recess and is substantially flush with or recessed from a surface of the scroll pump.

11. The scroll pump as claimed in claim 7 , wherein a counter-weight is disposed axially between the bellows arrangement and the orbiting scroll.

12. The scroll pump as claimed in claim 11 , wherein the counter-weight is generally axially aligned with the second bearing means.

13. The scroll pump as claimed in claim 11 , wherein the counter-weight is fastened to the drive shaft with an axially extending fastener.

14. The scroll pump as claimed in claim 9 , wherein the through-bore has a counter-sunk recess so that when the fastener is inserted through the through-bore, a head of the fastener is received in the recess and is substantially flush with or recessed from a surface of the scroll pump.

15. The scroll pump as claimed in claim 9 , wherein a counter-weight is disposed axially between the bellows arrangement and the orbiting scroll.

16. The scroll pump as claimed in claim 10 , wherein a counter-weight is disposed axially between the bellows arrangement and the orbiting scroll.

17. A method of assembling a scroll pump, the scroll pump comprising: a housing; a shaft supported by a first bearing; an orbiting scroll on an eccentric portion of the shaft supported by a second bearing; and a bellows arrangement; the method comprising the steps carried out sequentially of:

mounting the first bearing and the drive shaft for rotation relative to the housing;

fastening a first flange portion of the bellows arrangement relative to the housing;

fastening the orbiting scroll having a bore to a second flange portion of the bellows arrangement with at least one fastener positioned through the bore; and

fixing the second scroll relative to the housing for co-operation with the orbiting scroll.

18. The method as claimed in claim 17 , further comprising the step of fastening the second bearing relative to the orbiting scroll and mounting the second bearing to the eccentric shaft portion prior to the step of fastening the orbiting scroll to the bellows arrangement.

19. The method as claimed in claim 17 , further comprising the step of inserting the fastener through the bore so as to be substantially flush with a surface of the orbiting scroll.

20. The method as claimed in claim 17 , further comprising the step of fastening a counter-weight to the drive shaft with an axially extending fastener.

21. The method as claimed in claim 20 , wherein the step of fastening the counter-weight to the drive shaft takes place subsequent to the step of fastening the first flange portion of the bellows arrangement relative to the housing.