Vacuum pump system

Abstract

A vacuum pump system for evacuating a chamber, in particular a lock or a process chamber, is provided that includes a main vacuum pump preferably configured as a screw pump. An inlet of the main vacuum pump is connected with the chamber to be evacuated. As seen in the feeding direction of the main vacuum pump an auxiliary vacuum pump is arranged which is in particular a Roots pump. An outlet area of the main vacuum pump is connected with a main outlet on the one hand and an inlet of the auxiliary vacuum pump on the other hand. Further, an outlet of the auxiliary vacuum pump is connected with the main outlet.

Claims

1. A vacuum pump system for evacuating a chamber, comprising: a main vacuum pump whose inlet is connected with the chamber to be evacuated, an auxiliary vacuum pump downstream of said main vacuum pump as seen in the direction of flow, wherein said main vacuum pump comprises an outlet area which is connected with a main outlet on the one hand and an inlet of said auxiliary vacuum pump on the other hand, wherein an outlet of said auxiliary vacuum pump is connected with said main outlet, wherein the main vacuum pump is a screw pump, wherein the auxiliary vacuum pump is selected from a group consisting of a Roots pump, a claw pump, and a side channel pump, wherein a suction capacity of the auxiliary vacuum pump is smaller than one tenth of a suction capacity of the main vacuum pump, wherein at least one rotor element of the main vacuum pump and at least one rotor element of the auxiliary vacuum pump are arranged on a common shaft.

2. The vacuum pump system according to claim 1, wherein in the main outlet a check valve is arranged which prevents a medium from flowing back into the outlet area.

3. The vacuum pump system according to claim 2, wherein the outlet of the auxiliary vacuum pump is connected with the main outlet at a location downstream of the check valve.

4. The vacuum pump system according to claim 1, wherein the main vacuum pump and the auxiliary vacuum pump are arranged in a common housing.

5. The vacuum pump system according to claim 1, wherein the main vacuum pump and the auxiliary vacuum pump are connected with a common drive motor.

6. The vacuum pump system according to claim 1, wherein the main vacuum pump has two rotor elements and the auxiliary vacuum pump has two rotor elements, wherein one of the two rotor elements of the main and auxiliary vacuum pumps are respectively arranged on one common shaft, and wherein another of the two rotor elements of the main and auxiliary vacuum pumps are respectively arranged on a second common shaft.

7. The vacuum pump system according to claim 6, wherein the drive motor drives one of the two common shafts.

8. The vacuum pump system according to claim 1, wherein the main vacuum pump comprises an internal compression of at least >2.

9. The vacuum pump system according to claim 1, wherein the auxiliary vacuum pump comprises an internal compression of less than 2.

10. A vacuum pump system for evacuating a chamber, comprising: a housing having an intermediate wall that divides the housing into a main region and an auxiliary region; a main vacuum pump in the main region of the housing, the main vacuum pump having a main inlet into the main region from the chamber and a main outlet out of the housing, the main inlet being connected with the chamber to be evacuated; and an auxiliary vacuum pump in the auxiliary region of the housing, the auxiliary vacuum pump having an auxiliary inlet connected with the main region through the intermediate wall and an auxiliary outlet out of the housing, the auxiliary outlet being connected with the main outlet, wherein the main vacuum pump and the auxiliary vacuum pump are different types of pumps, wherein the main vacuum pump has two rotor elements and the auxiliary vacuum pump has two rotor elements, wherein one of the two rotor elements of the main and auxiliary vacuum pumps are respectively arranged on a first common shaft, and wherein another of the two rotor elements of the main and auxiliary vacuum pumps are respectively arranged on a second common shaft, wherein the main vacuum pump is a screw pump and the auxiliary vacuum pump is selected from a group consisting of a Roots pump, a claw pump, and a side channel pump.

11. The vacuum pump system according to claim 10, further comprising a check valve in the main outlet arranged to prevent flow back into the main vacuum pump.

12. The vacuum pump system according to claim 11, wherein the auxiliary outlet is connected with the main outlet downstream of the check valve.

13. The vacuum pump system according to claim 10, further comprising a drive motor outside of the housing and connected to the first common shaft.

14. The vacuum pump system according to claim 13, further comprising gears on the first and second common shafts outside of the housing, the gears being configured so that the drive motor also drives the second common shaft.

15. A vacuum pump system for evacuating a chamber, comprising: a housing having an external wall and an intermediate wall, the intermediate wall dividing the housing into a main region and an auxiliary region, the external wall having a main inlet connecting the chamber and the main region, a main outlet connecting the main region and a region external to the housing, and an auxiliary outlet connecting the main region and the region external to the housing, the intermediate wall having an auxiliary inlet connecting the main and auxiliary regions; a screw pump in the main region; and an auxiliary vacuum pump in the auxiliary region, the auxiliary vacuum pump consists of a Roots pump or a claw pump or a side channel pump; and a common shaft through the intermediate wall and the external wall in the auxiliary region, the common shaft driving both the screw pump and the auxiliary vacuum pump.

16. The vacuum pump system according to claim 15, wherein the screw pump has an internal compression of at least >2 and the auxiliary vacuum pump has an internal compression of less than 2.

17. The vacuum pump system according to claim 16, wherein the auxiliary vacuum pump has a suction capacity that is smaller than one tenth of a suction capacity of the screw pump.

18. The vacuum pump system according to claim 15, wherein the auxiliary vacuum pump has a suction capacity that is smaller than one tenth of a suction capacity of the screw pump.

19. The vacuum pump system according to claim 15, further comprising a check valve that prevents backflow through the main outlet.

20. The vacuum pump system according to claim 19, wherein the auxiliary outlet is connected with the main outlet downstream of the check valve.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a schematic sectional view of a preferred embodiment of the vacuum pump system according to the disclosure.

(2) FIG. 2 shows a schematic sectional view of an alternate embodiment of the vacuum pump system according to the disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(3) In FIG. 1, the schematic representation of a preferred embodiment of the disclosure a screw pump 12 is arranged in a common housing 10 is shown. The screw pump 12 comprises two helical rotor elements 18 respectively arranged on a rotor shaft 14, 16.

(4) The two rotor shafts 14, 16 extend through an intermediate wall 20 of the housing, each carrying a rotor element 22 of a Roots pump 24.

(5) The shaft 14 shown on the left-hand side in the drawing is further connected with an electric drive motor 26.

(6) The electric motor 26 drives the shaft 14. The shaft 16 is driven via gears 28 which are respectively connected with one of the two shafts 14, 16.

(7) For example, the inlet 30 of the main vacuum pump 12 is connected via a connecting line 31 with a chamber not shown which is to be evacuated. The screw pump 12 then feeds the medium to an outlet area 32 and/or an outlet chamber 32. From there the medium passes through the main outlet 34. In the main outlet 34 a check valve 36 is arranged.

(8) In particular during holding operation a small volume of a medium is sucked in via an inlet 38 of the auxiliary vacuum pump 24 and ejected via an outlet 40 of the auxiliary vacuum pump. The outlet 40 is connected with the main outlet 34, wherein the connection is realized in the main outlet 34 downstream of the check valve 36 as seen in the direction of flow.

(9) In FIG. 2, the schematic representation of an alternate embodiment of the disclosure a screw pump 12 is arranged in a common housing 10 is shown. Here, the two rotor shafts 14, 16 extend through an intermediate wall 20 of the housing, each carrying a pump elements 22 of a claw pump or a side channel pump 24.