Vacuum pump having a silencer

Abstract

A vacuum pump comprises rotor elements arranged in a suction chamber. An outlet duct is connected to an exhaust pipe. For the purpose of silencing, sound expansion spaces are provided in the outlet duct, which are integrated into the pump housing. Alternatively or in addition to these sound expansion spaces, sound expansion spaces may be provided in an inlet duct which is used for the inlet of gas ballast, said sound expansion spaces being preferably likewise integrated into the pump housing.

Claims

1. A two-shaft vacuum pump, comprising: a pump housing defining a suction chamber and having a gas inlet and a gas outlet, rotor elements arranged in said suction chamber for forming a plurality of successive pump stages, an inlet duct for gas ballast connected to one of said pump stages, and at least one sound expansion space arranged between duct sections of said inlet duct and is partially integrated into said pump housing and partially integrated into a removable pump housing cover, the sound expansion space having at least one change in cross-section.

2. The vacuum pump according to claim 1, further comprising: a discharge duct connected to the gas outlet, and the at least one sound expansion space arranged between duct sections of said discharge duct.

3. The vacuum pump according to claim 1, wherein at an inlet opening of the sound expansion space a multiple increase of the cross-section is realized.

4. The vacuum pump according to claim 1, wherein two identically configured sound expansion spaces are arranged one behind the other in the direction of flow.

5. The vacuum pump according to claim 1, wherein in the inlet duct at least two identically configured sound expansion spaces and in the outlet duct at least two identically configured sound expansion spaces are arranged.

6. The vacuum pump according to claim 1, wherein an inlet opening and an outlet opening of the at least one sound expansion space are arranged in a staggered manner relative to each other.

7. The vacuum pump according to claim 1, further comprising a gas ballast inlet which is open against the atmosphere or a rotary valve which is provided at the gas ballast inlet.

8. The vacuum pump according to claim 1, further comprising at least one duct section has connected thereto a pipe section projecting into the at least one sound expansion space.

9. A two-shaft vacuum pump, comprising: a pump housing defining a suction chamber and having a gas inlet and a gas outlet, rotor elements arranged in said suction chamber for forming a plurality of successive pump stages, an inlet duct for gas ballast connected to one of said pump stages, at least one sound expansion space arranged between duct sections of said inlet duct and is partially integrated into said pump housing and partially integrated into a removable pump housing cover, a discharge duct connected to the gas outlet, and the at least one sound expansion space arranged between duct sections of said discharge duct.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Hereunder the disclosure is elucidated in detail on the basis of preferred embodiments with reference to the accompanying drawings in which:

(2) FIG. 1 shows a schematic sectional view of an embodiment according to the disclosure of a vacuum pump having a gas ballast inlet,

(3) FIG. 2 shows a schematic sectional view of a vacuum pump having sound expansions spaces, which are arranged according to the disclosure, in the discharge duct,

(4) FIG. 3 shows a perspective schematic sectional view where silencers are provided both in the discharge duct and the inlet duct for gas ballast,

(5) FIG. 4 shows a perspective view of an alternative embodiment essentially corresponding to FIG. 3, and

(6) FIGS. 5 to 7 show schematic diagrammatic sketches of alternative configurations of sound expansion spaces for silencing purposes.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(7) In FIG. 1 a vacuum pump having a pump housing 10 is schematically shown. In the pump housing 10 a suction chamber 22 is configured for forming a plurality of stages 12, 14, 16, 18, 20. The illustrated exemplary embodiment is a claw pump, for example, wherein per stage one rotor element 24 is arranged in the suction chamber 22. The rotor elements 24 are held by a common shaft 26 which is in particular supported in the housing 10. Per pump stage 12, 14, 16, 18, 20 the rotor elements 24 cooperate with a respective further rotor element not shown, wherein these are held by a second shaft.

(8) In FIG. 1 the gas is delivered from the left to the right, wherein the gas is taken in through a gas inlet 28 and discharged via a gas outlet 30.

(9) The last but one pump stage 14 in the exemplary embodiment has connected thereto an inlet duct 32 for feeding gas ballast. The inlet duct 32 comprises a duct section 34 configured as a bore in the housing 10. Further, the inlet duct comprises in a housing cover 36 connected to the housing 10 duct sections 38, 40 configured as grooves and another duct section 42 configured as a bore.

(10) Between two duct sections 38, 40 and 40, 42, respectively, a respective sound expansion space 44 is provided. In the illustrated exemplary embodiment, the sound expansion space is partly provided in the housing cover 36 and partly in the housing 10. Thus the sound expansion spaces 44 are easy to clean by removing the housing cover 36.

(11) In the exemplary embodiment illustrated in FIG. 1, the duct section 42 of the inlet duct 32 has connected thereto an inlet valve 45 for gas ballast. This is a valve having a rotatable valve body 46 for opening and closing valve inlet ducts 48.

(12) The sectional view shown in FIG. 2 also illustrates the vacuum pump shown in FIG. 1 according to a preferred embodiment, wherein a different sectional plane is selected that, relative to the sectional plane illustrated in FIG. 1, lies in front of or behind the latter. The portion of the vacuum pump illustrated in FIG. 2 is the outlet. Here, the discharge duct 30 comprises a duct section 50 arranged as a bore in the housing 10. A groove arranged in the housing cover 36 and forming another duct section 52 adjoins the duct section 30. A sound expansion space 44 adjoins the former in the direction of flow in accordance with the configuration of the inlet duct of FIG. 1, which sound expansion space is connected to a duct section 54 configured as a groove in the cover 36. Another sound expansion space 44 adjoins said duct section, which sound expansion space is then connected to another duct section 56. The duct section 56 enters the exhaust pipe 58 or is connected therewith.

(13) The sound expansion spaces 44 which are arranged in the discharge duct 30 and between the corresponding duct sections 52, 54, 56, respectively, are configured in accordance with the sound expansion spaces 44 of the inlet duct (FIG. 1).

(14) FIG. 3 shows a schematic perspective view of the housing cover 36, wherein an upper side 60 of the housing cover 36 abuts on a lower side 62 of the pump housing 10 in the assembled state (FIGS. 1 and 2). As can in particular be seen in FIG. 3, in the illustrated exemplary embodiment the sound expansion spaces 44 are of identical configuration. The sound expansion spaces 44 respectively comprise a circular cross-section, wherein a bottom side is rounded in the edge area. In addition, from the exemplary embodiment illustrated in FIG. 3 it can be seen that the individual duct sections 38, 40, 42 and 52, 54, 56, respectively, are arranged in a horizontally and vertically staggered manner. This staggered arrangement improves the silencing effect. The sound waves entering a sound expansion space 44 cannot directly travel into the opposite duct section due to the staggered arrangement.

(15) For further improvement of the silencing effect it is possible, as illustrated in FIG. 4, to connect to the duct sections 38, 40, 42 and 52, 54, 56, respectively, pipe sections 64 which respectively project into a sound expansion space 44.

(16) In FIGS. 5 to 7 further possible embodiments of sound expansion spaces 44 of different configurations are diagrammatically illustrated. The corresponding sound expansion spaces 44, which may be more than two series-connected sound expansion spaces 44, can be arranged for silencing purposes both for the inlet of the gas ballast and for the outlet of the gas. Here, it is particularly advantageous to provide the sound expansion spaces with additional bosses or protrusions 66, as illustrated in FIGS. 5 and 6, since thereby a further silencing effect is possible. It is also preferred that the gas flowing into and/or out of a sound expansion space 44 is guided through a pipe section 64.