Sliding vane rotary pump

Abstract

The invention relates to a rotary vane pump (1) for conveying a fluid to be conveyed, with a housing (2), with a rotor receiving chamber (3) and a lubricant chamber (14). An eccentrically arranged rotor (4) is provided in a rotor receiving chamber (3) in such a way that at least one conveying chamber (11) is produced, the volume of which varies cyclically during rotation of the rotor (4). Furthermore, the rotary vane pump (1) has an intake channel (12) for feeding the fluid to be conveyed into the conveying chamber (11) and a discharge channel (13) for discharging the fluid to be conveyed out of the conveying chamber (11) in the direction of the lubricant chamber (14), wherein a valve device (21) is provided between the discharge channel (13) and the lubricant chamber (14) in order to prevent a backflow of fluid, in particular of lubricant and/or of fluid to be conveyed, from the lubricant chamber (14) into the conveying chamber (11). The rotary vane pump (1) is furthermore designed and set up in such a way that the discharge channel (13) is arranged in such a way that it opens into the lubricant chamber (14). Furthermore, the rotary vane pump (1) has at least one ventilation channel (26), which is fluidically connected by a conveying chamber end (28) to the conveying chamber (11) and fluidically connected by a ventilation end (27) to a chamber outside the conveying chamber (11), as well as at least one compensation channel (29), which is fluidically connected by a conveying chamber end (31) to the conveying chamber (11) and fluidically connected by a compensation end (30) to the lubricant chamber (14). In this way, the rotary vane pump (1) is designed and set up in such a way that the compensation end (30) opens into the lubricant chamber (14) below the lubricant level (24) in an operating state of the rotary vane pump (1) and opens into the lubricant chamber (14) above the lubricant level (34) in a resting state of the rotary vane pump (1).

Claims

1. Rotary vane pump for conveying a fluid to be conveyed, a housing with a rotor receiving chamber and a lubricant chamber, a rotor arranged eccentrically in the rotor receiving chamber to form a conveying chamber whose volume varies cyclically when the rotor rotates, an intake channel for supplying the fluid to be conveyed into the conveying chamber and a discharge channel for discharging the fluid to be conveyed out of the conveying chamber in a direction of the lubricant chamber, a valve device provided between the discharge channel and the lubricant chamber configured to prevent a backflow of fluid out of the lubricant chamber into the conveying chamber, wherein the discharge channel is configured to open into the lubricant chamber, a ventilation channel connected fluidically by a first conveying chamber end thereof to the conveying chamber, and connected fluidically by a ventilation end thereof to a chamber outside the conveying chamber, and a compensation channel connected fluidically by a second conveying chamber end thereof to the conveying chamber, and connected fluidically by a compensation end thereof to the lubricant chamber, whereby the rotary vane pump is configured to open the compensation end into the lubricant chamber below a lubricant level in an operating state of the rotary vane pump, and to open into the lubricant chamber above the lubricant level in a resting state of the rotary vane pump.

2. Rotary vane pump according to claim 1, wherein the first conveying chamber end of the ventilation channel and/or the compensation end of the compensation channel open(s) directly into the conveying chamber of the rotary vane pump.

3. Rotary vane pump according to claim 1, wherein the compensation channel is arranged such that in the operating state of the rotary vane pump, said compensation channel opens into the lubricant chamber completely below the lubricant level of the lubricant chamber, and in the resting state of the rotary vane pump said compensation channel opens into the lubricant chamber at least partially above the lubricant level.

4. Rotary vane pump according to claim 1, wherein the ventilation end of the ventilation channel opens into the lubricant chamber.

5. Rotary vane pump according to claim 1, wherein the discharge channel is configured such that in the operating state of the rotary vane pump said discharge channel opens into the lubricant chamber at least partially below the lubricant level of the lubricant chamber.

6. Rotary vane pump according to claim 1, wherein the lubricant chamber has a lubricant bath, adjacent to the discharge channel, and a lubricant storage area, wherein the lubricant bath and the lubricant storage area are separated from one another by a partition wall.

7. Rotary vane pump according to claim 6, wherein the partition wall has a drain opening and/or a recess in a region of an upper edge of the partition wall.

8. Rotary vane pump according to claim 6, wherein a volume-reducing device is provided in an upper filling level region of the lubricant chamber and/or of the lubricant bath.

9. Rotary vane pump according to claim 1, wherein the valve device is configured at least in some areas as a valve tongue device.

10. Rotary vane pump according to claim 1, comprising a plurality of intake channels and/or discharge channels and/or valve devices and/or valve tongue devices and/or ventilation channels and/or compensation channels and/or conveying chambers and/or rotors and/or rotor receiving chambers.

11. Rotary vane pump according to claim 1, wherein the ventilation channel and/or the compensation channel comprises a fluid flow rate limiting device.

12. Rotary vane pump according to claim 11, wherein said valve device is configured as a sealing valve device, and said valve tongue device is configured to be substantially free of recesses.

13. Rotary vane pump according to claim 6, wherein a dimensioning of a volume of the lubricant bath is selected such that a lowering of the lubricant level during a transition from the operating state to the resting state of the rotary vane pump is realized by an initial lubricant transfer out of the lubricant chamber and/or the lubricant bath via the compensation channel into the conveying chamber, whereby maximum lubricant transfer into the conveying chamber is dimensioned such that a restart of the rotary vane pump is not impaired by the lubricant present in the conveying chamber.

14. Rotary vane pump according claim 6, wherein the rotary vane pump is configured such that a relative arrangement of lubricant level in the lubricant chamber and/or in the lubricant bath on the one hand, and in the discharge channel and/or the compensation end of the compensation channel on the other hand, results from a variation of the lubricant level.

15. Rotary vane pump according to claim 1, wherein the conveying chamber is at least partially delimited by wall elements which are slidable and/or pivotable relative to the rotor.

16. Rotary vane pump according to claim 11, wherein the fluid flow rate limiting device of the ventilation channel is dimensioned such that in the operating state of the rotary vane pump a noise reduction is realized without significant impairment of a conveying capacity of the rotary vane pump.

17. Rotary vane pump according to claim 11, wherein the fluid flow rate limiting device of the compensation channel is dimensioned such that sufficient ventilation of the conveying chamber is realized during a shutdown of the rotary vane pump without significant impairment of the operating state by lubricant flowing back through the compensation channel and/or the fluid to be conveyed.

Description

(1) Further advantages, features and functions of the invention emerge from the following detailed description of the invention in combination with the corresponding drawings. The drawings show:

(2) FIG. 1, a schematic cross-sectional view of a rotary vane pump with laterally arranged lubricant chamber;

(3) FIG. 2, an enlarged detail of FIG. 1 in the region of discharge channel, ventilation channel and compensation channel;

(4) FIG. 3, a lateral top view of the region with the valve tongue device of the rotary vane pump shown in FIG. 1;

(5) FIG. 4, a lateral top view of an overflow partition wall in the lubricant chamber of the rotary vane pump shown in FIG. 1.

(6) Shown in FIG. 1 in a schematic cross-sectional view is a rotary vane pump 1. Such rotary vane pumps 1 are known from their basic structure in the state of the art and are used for a variety of applications.

(7) The rotary vane pump 1 has a housing 2, in which a hollow spacethe rotor receiving chamber 3is formed. Disposed in the rotor receiving chamber 3 in an eccentrically offset way is a rotor 4, which can be set in rotational movement along a rotational axis 5. In the embodiment example shown, the rotor 4 has three slide slots 6, in each of which a wall element 7 (often also referred to as a slide, vane or slide blade) is arranged so as to be displaceable relative to the rotor 4 in such a way that the wall elements 7 rotate together with the rotor 4. Through the rotation of the rotor 4 about the rotational axis 5, the wall elements 7, owing to the centrifugal force, are pressed against an inner wall 8 of the rotor receiving chamber 3. With the aid of a lubricant 10, the mechanical friction between the front ends 9 of the wall elements 7 and the inner wall 8 of the rotor receiving chamber 3 is reduced, and thus the attrition of the rotary vane pump 1 significantly decreased. At the same time, the lubricant film between the front ends 9 of the wall elements 7 and the inner wall 8 of the rotor receiving chamber 3 produces a sealing function, so that no fluid to be conveyed is able to flow by here.

(8) The wall elements 7 divide the rotor receiving chamber 3 (taking into account the rotor 4) into three conveying chambers 11, namely conveying chambers 11a, 11b and 11c. Due to the current position of rotor 4 and dead center 15, conveying chamber 11c can be further divided into two sub-conveying chambers 11c, 11c separated by the dead center. Due to the eccentric arrangement of the rotor 4 in the rotor receiving chamber 3, the volume of the conveying chambers 11 varies cyclically in the course of a rotation of the rotor 4 of the rotary vane pump 1, so that a fluid can be conveyed.

(9) The fluid to be conveyed is drawn via an intake opening 12 into one of the three conveying chambers 11 (currently conveying chamber 11a and possibly also conveying chamber 11c). The conveying chamber 11 in question isas already mentionedbounded by two adjacent wall elements 7. Due to the initial expansion of the respective conveying chamber 11, fluid to be conveyed is sucked into the respective conveying chamber 11 (conveying chamber 11a). After the respective conveying chamber 11 is separated from the intake opening 12 by the rotation of the rotor 4 from a certain angular position, its volume is reduced again due to the shape of the rotor receiving chamber 3 and the rotor 4 arranged eccentrically therein, so that the fluid contained therein is compressed (conveying chamber 11b). From a certain angular position of the rotor 4 or the respective conveying chamber 11, a fluidic connection to the discharge channel 13 is established and the fluid to be conveyed is ejected from the conveying chamber 11 via the discharge channel 13 into the lubricant chamber 14 (conveying chamber 11c). The ejection of the fluid into the lubricant chamber 14 takes place via the valve tongue device 21, which opens when the pressure in the conveying chamber 11 is slightly higher than the pressure in the lubricant chamber 14 (typically close to atmospheric pressure). The described cycle then starts again from the beginning. Mention should be made of the so-called dead center 15, which separates the area of the rotor receiving chamber 3 adjacent to the discharge channel 13 from the area of the rotor receiving chamber 3 adjacent to the intake opening 12.

(10) The lubricant chamber 14 is connected via a flange area 16 to the area of the housing 2 of the rotary vane pump 1 in which the rotor receiving chamber 3 is formed with the rotor 4. In the present embodiment, the lubricant chamber 14 has two different areas. These are the lubricant bath 17 arranged adjacent to the discharge channel 13 and the lubricant storage area 18 designed separately therefrom. Lubricant bath 17 and lubricant storage area 18 are separated from each other by a partition wall, which is designed as an over-flow partition wall 19.

(11) The discharge end 20 facing the lubricant bath 17 is connected to the lubricant bath 17 via a valve device, which in this case is designed as a valve tongue device 21. The valve tongue device 21 is connected to the housing 2 of the rotary vane pump 1 by means of screws 22, for example. In the embodiment example shown here, the valve tongue device 21 has four elastic valve tongue areas 23 (see also view according to FIG. 3), which cover the respective discharge ends 20 of the discharge channels 4 <sic. 13>, which are also arranged next to each other in the axial direction of the axis of rotation 5 of the rotor 4. Thanks to the elastic valve tongue areas 23, the fluid to be conveyed by the rotary vane pump 1 can only flow from the rotor receiving chamber 3 in the direction of the lubricant chamber 14but not in the reverse direction.

(12) In the case under consideration, the rotary vane pump 1 is designed in such a way that the discharge ends 20 of the discharge channels 13 open into the lubricant bath 17 in an operating state of the rotary vane pump 1 below the lubricant level 24 in the operating state of the rotary vane pump 1. This has the advantage that the lubricant 10 in the lubricant bath 17 exerts a certain fluid pressure on the elastic valve tongue areas 23, and thus the discharge ends 20 of the discharge channels 13 are securely closed (fluid-tight) by the valve tongue areas 23. Thereby the ambient pressure in the lubricant chamber 14 naturally exerts a pressure on the lubricant 10 in the lubricant bath 17. In addition, the lubricant 10 causes a certain sealing of any gaps and cracks that may be present, so that the tightness of the valve tongue device 21 is also particularly high as a result.

(13) As can be seen in particular from the enlarged view in FIG. 2, in the present embodiment example shown of a rotary vane pump 1, in addition to the discharge channels 13, there is also a ventilation channel 26 which is in the present case completely separate from the discharge channel 13, as well as (in the present case) two compensation channels 29also designed completely separate from the discharge channel 13 and the ventilation channel 26.

(14) The ventilation channel 26 has a ventilation 27 which opens into the lubricant chamber 14 (or the lubricant bath 17) above the lubricant level 24 in the operating state of the rotary vane pump 1. The conveying chamber end 28 of the ventilation channel 26 is arranged at a suitable location in the rotor receiving chamber 3, preferably directly adjacent to the dead center 15. Thanks to the ventilation channel 26, a small amount of air or a small amount of fluid (in particular gaseous fluid) present in the lubricant chamber 14 can flow into the compression area of the rotor receiving chamber 3. This leads to a reduction in noise development, in particular at rotational speeds of the rotor 4 which lie in a limit range. Since the ventilation opening 26 can be optimized for the purpose of noise reduction, a partly significant noise reduction can be realized with a comparatively small construction effort, without other advantageous properties of the rotary vane pump 1 (which will be explained in more detail in the following) being adversely affected to a significant extent.

(15) In particular, it is possible to provide the ventilation channel 26 with a suitably dimensioned throttle 32. In addition, it is also possible to make the throttle 32 interchangeable, so that the rotary vane pump 1 can be quickly adapted to different operating environments and for different purposes (also retroactively).

(16) Furthermore, in the embodiment example shown here, two compensation channels 29 are provided, which are arranged at the same height, but axially offset to each other (with respect to the axis of rotation 5 of the rotor 4) (see also view in FIG. 3). Of course, a different number of compensation channels 29 is also possible (which, by the way, also applies to the ventilation channels 26).

(17) The compensation ends 30 of the compensation channels 29 are arranged in such a way that they lie just below the lubricant level 24 of the lubricant bath 17 in the operating state of the rotary vane pump 1. As a result, a certain sealing effect is realized by the lubricant 10 in the lubricant bath 17, so that only a minor (net) fluid throughput (if any) occurs through the outlet channels 29 during operation of the rotary vane pump 1. This applies both to a flow of fluid to be conveyed out of the rotor receiving chamber 3 in the direction of the lubricant chamber 14 and to a flow of fluid (in particular lubricant 10) out of the lubricant chamber 14 or out of the lubricant bath 17 in the direction of the rotor receiving chamber 3.

(18) It is particularly noteworthy with regard to the arrangement of the compensation ends 30 of the outlet channels 29 that these are located completely below the lubricant level 24 in the operating state of the rotary vane pump 1, but only just below the lubricant level 24 in the operating state of the rotary vane pump 1. This is relevant because after a shutdown of the rotary vane pump 1 (whether intentional or unintentional), the compensation channels 29 should be exposed as quickly as possible. The lubricant level in the lubricant bath 17 should therefore drop as quickly as possible to a lubricant level 34 when the rotary vane pump 1 is switched off (indicated by a dashed line in FIGS. 1 to 3). This will be discussed in more detail below.

(19) In an operating state of the rotary vane pump 1, a fluid to be conveyed that is enriched with the lubricant 10 (suction of the fluid to be conveyed via the intake port 12) is conveyed by means of the cyclically increasing and decreasing conveying chambers 11 from the conveying chamber 11 (in this case conveying chamber 11c) located adjacent to the discharge channel 13 into the discharge channel 13. Due to the resulting pressure, the elastic valve tongue areas 23 of the valve tongue device 31 are pressed away from the wall of the flange area 16 so that the lubricant-fluid mixture enters the lubricant bath 17 or the oil chamber 14. This continuous flow of lubricant-fluid mixture (and thus also of lubricant 10) keeps the lubricant level 24 in the operating state of the rotary vane pump 1 in an upper range. The upper lubricant level 24 is essentially defined by the upper edge 35 of the overflow partition 19. The function of the optional recesses 36 in the area of the upper edge 35 of the overflow partition 19 and the optional drain openings 37 in the overflow partition 19 will be discussed below. In any case, recesses 36 and drain openings 37if presentare to be dimensioned with regard to number and size in such a way that the lubricant level 24 in the operating state of the rotary vane pump 1 remains in the region of the upper edge 35 of the overflow partition 19 in all realistically expected operating states of the rotary vane pump 1, whereby a rise of the lubricant level 24 above the upper edge 35 of the overflow partition 19 takes place by overflow 38 of the lubricant 10 (indicated in FIGS. 1 and 2 by an arrow 38), the overflow 38 causing the lubricant 10 to flow from the lubricant bath 17 into the lubricant storage area 18 of the lubricant chamber 14.

(20) Lubrication of the rotary vane pump 1, in particular in the area of the rotor 4 or the rotor receiving chamber 3, can be realized by lubricant pumps not shown here, which for example release lubricant 10 in the area of the intake port 12 of the rotary vane pump. Such lubricant pumps as well as such a lubrication of the rotary vane pump 1 are known as such in the prior art.

(21) When the rotary vane pump 1 stops (for example, due to an intended shutdown process, but also due to an unintentional failure), air or fluid (in particular predominantly gaseous fluid) is drawn out of the lubricant chamber 14 into the rotor receiving chamber 3 via the ventilation channel 26, on the one hand. In addition, lubricant 10 initially flows from the lubricant bath 17 into the rotor receiving chamber 3 via the compensation channel 29. Since, due to the stopping of the rotary vane pump 1, there is no replenishment of lubricant 10 into the lubricant bath 17 (via the discharge channels 13), the initial lubricant level 24 in the operating state of the rotary vane pump 1 quickly drops to the lowered lubricant level 34 in the switched-off state of the lubricant pump 1. Accordingly, the compensation ends 30 of the compensation channels 29 are now exposed, so that air or substantially gaseous fluid is now drawn from the lubricant chamber 14 into the rotor receiving chamber 3. This allows the pressure in the rotor receiving chamber 3 to be equalized particularly quickly. Since the rotor receiving chamber 3 can thus be brought to ambient pressure (typically atmospheric pressure) particularly quickly, it can be ensured that only minimal quantities of lubricant enter the rotor receiving chamber 3. This is an advantageous way to prevent the rotor receiving chamber 3 from filling up with lubricant.

(22) A rapid lowering of the lubricant level from the operating state level 24 to the switched-off level 34 can be accelerated by optional recesses 36 in the area of the upper edge 35 of the overflow partition wall 19 and/or by drain openings 37 in the overflow partition wall 19. The number and size of the recesses 36 and/or drain openings 37 can be selected in such a way that the amount of lubricant draining through these recesses/openings is compensated for under all realistically expected operating conditions in an operating state of the rotary vane pump 1 (usually plus a safety margin). To enable the rotary vane pump 1 to be adapted to different applications and/or operating conditions, the recesses 36 and/or the drain openings 37 can be designed to be reversibly closable, for example by providing an internal thread (especially in the case of the drain openings 37) or by the possibility of a slip-on discharge edge (especially in the case of recesses 36 in the area of the upper edge 35).

(23) Furthermore, in the embodiment example shown, a bead 39, which is also optional, is attached in the area of the upper edge 35 of the overflow partition wall 19. This tapers the cross-section (horizontal cross-section in the view of FIG. 1 and FIG. 2) so that a reduced volume of lubricant 10 is sufficient to lower the lubricant level in the operating state 24 to the lubricant level in the switched-off state 34 of the rotary vane pump 1 (compared to the situation without bead 39). The bead 39 also increases the effectiveness of the recesses 36 and/or the drain openings 37 (if any).

(24) Furthermore, it is possible that only individual elements (or also a certain subset of the described features) of the embodiment example described in detail of the rotary vane pump 1 described here are picked out and combined with the generic description of the presently proposed rotary vane pump.