Improved rotary vane pump

Abstract

The present invention relates to a rotary vane pump (1) for transporting a fluid to be transported, comprising a housing (2) with a rotor-accommodating chamber (3) and a lubricant chamber (14). The rotor (4) is eccentrically arranged in the rotor-accommodating chamber (3) in such a way that at least one transport chamber (11) is created, the volume of which varies periodically during rotation of the rotor (4). The rotary vane pump (1) further comprises an intake channel (12) for supplying the fluid to be transported to the transport chamber (11) and a discharge channel (13) for discharging the fluid to be transported from the transport chamber (11) in the direction of the lubricant chamber (14). A valve device (21) is provided between the discharge channel (13) and the lubricant chamber (14) for preventing a backflow of fluid, in particular lubricant and / or the fluid to be transported, from the lubricant chamber (14) into the transfer chamber (11). The rotary vane pump (1) is further designed and installed so that the discharge channel (13) is positioned to open into the lubricant chamber (14). The rotary vane pump (1) further has at least one ventilation channel (26) fluidly connected to the transfer chamber (11) by a transfer chamber end (28) and fluidly connected to a chamber external to the transfer chamber (11) by a ventilation end (27), and at least one compensation channel (29) fluidly connected to the transfer chamber (11) by a transfer chamber end (31) and fluidly connected to the lubricant chamber (14) by a compensation end (30). In this way, the rotary vane pump (1) is designed and installed so that the compensation end (30) opens into the lubricant chamber (14) below the lubricant level (24) when the rotary vane pump (1) is operating, and opens into the lubricant chamber (14) above the lubricant level (34) when the rotary vane pump (1) is at rest.

Description

[Technical Field]

[0001] The present invention relates to a rotary vane pump for transporting a fluid to be transported. [Background technology]

[0002] A rotary vane pump has a housing with a cavity in which a rotatable rotor is eccentrically arranged. Typically, slot-like recesses (often called slide slots) are formed in the rotor, in which wall elements (so-called slides) are movably, particularly slidably, arranged. In many designs, the wall elements / slides are pressed against the inner wall of the housing cavity (rotor-accommodating chamber) by centrifugal force during rotor rotation. In this way, one or more transfer chambers are formed by the wall elements, and the volume of the transfer chamber(s) changes periodically during rotor rotation. By appropriately arranged inlet and outlet channels, the fluid to be pumped by the rotary vane pump can be transferred from the inlet channel to the outlet channel.

[0003] The lubricant contained in the lubricant chamber of the rotary vane pump is used to lubricate the parts that move mechanically relative to each other. Another function of the lubricant is to provide additional sealing between the inner wall of the housing and the wall element, between the wall element and the rotor, and between other components of the rotary vane pump.

[0004] Such rotary vane pumps are well known in the art and are used in a variety of applications, a typical application of such rotary vane pumps being the generation of low pressure / vacuum, for example in scientific applications, in the latter case mainly as one link in a series of different pump types (rotary vane pumps are typically used to generate so-called forevacuums or rough vacuums).

[0005] Although rotary vane pumps have proven their usefulness and are widely used, they still suffer from certain drawbacks.

[0006] A drawback of rotary vane pumps that is often criticized is the continuous noise they generate, so it is easy to see why a reduction in the operating noise they generate would be welcomed by many users.

[0007] Another problem arises with the shutdown of rotary vane pumps (which can be planned, e.g., by user intervention, or can occur unplanned, e.g., as a result of a malfunction). In this case, typical designs of rotary vane pumps tend to ingest lubricant into the rotor-accommodating or transfer chamber. The volume of lubricant ingested can subsequently cause problems when restarting the rotary vane pump, in particular by increasing operating noise, requiring increased drive torque, and / or increasing mechanical resistance. The latter can lead, in particular, to increased mechanical wear and, under adverse conditions, even damage to the rotary vane pump. It is easy to see that the design of rotary vane pumps still needs improvement due to the problems mentioned above, as well as others not described in detail here. It is therefore not surprising that numerous possible improvements have already been proposed in the prior art.

[0008] For example, WO 2013 / 139570 proposes a vacuum rotary vane pump in which a valve device is disposed between the discharge channel of the transfer chamber of the rotary vane pump and the lubricant chamber to prevent backflow of fluid from the lubricant chamber into the transfer chamber. The use of a compensation channel is proposed, which is connected to the discharge channel and the lubricant chamber and is integrated with the valve device. This is intended to provide rapid pressure equalization in the transfer chamber when the rotary vane pump is switched off, thereby quickly bringing the transfer chamber to atmospheric pressure and preventing the transfer chamber from filling with lubricant via the lubricant supply. A different design for such a compensation channel between the transfer chamber and the lubricant is proposed in WO 2007 / 006666.

[0009] EP 3470678 A1 proposes providing a compensation channel between the transfer chamber and the lubricant chamber of a rotary vane pump, the opening of the compensation channel being located in the area of ​​the overflow partition of the lubricant chamber.

[0010] While such proposals certainly have some merit, further improvements are still needed. Summary of the Invention [Problem to be solved by the invention]

[0011] The object of the invention is therefore to propose a rotary vane pump for transporting a fluid to be transported, which has improved operating behavior. [Means for solving the problem]

[0012] A rotary vane pump for transporting a fluid to be transported having the features of claim 1 achieves this object.

[0013] A rotary vane pump for transporting a fluid to be transported is proposed. The rotary vane pump includes a housing with a rotor accommodating chamber, a lubricant chamber, a rotor eccentrically disposed within the rotor accommodating chamber, an intake channel for supplying the fluid to be transported into the transfer chamber, and a discharge channel for discharging the fluid to be transported from the transfer chamber toward the lubricant chamber. The rotor is eccentrically disposed within the rotor accommodating chamber so that there is at least one transfer chamber whose volume periodically changes during rotation of the rotor. A valve device is provided between the discharge channel and the lubricant chamber to prevent backflow of fluid, particularly lubricant and / or the fluid to be transported, from the lubricant chamber into the transfer chamber. The rotary vane pump is designed and equipped so that the discharge channel opens into the lubricant chamber. The rotary vane pump includes at least one ventilation channel, which is fluidly connected to the transfer chamber by a transfer chamber end and to a space outside the transfer chamber by a ventilation end. The rotary vane pump further comprises at least one compensation channel, the compensation channel being fluidly connected to the transfer chamber by a transfer chamber end and to the lubricant chamber by a compensation end. The rotary vane pump is designed and equipped such that, in the operating state of the rotary vane pump, the compensation end of the compensation channel opens into the lubricant chamber below the lubricant level. In the resting state (or switched-off state) of the rotary vane pump, the compensation end of the compensation channel opens into the lubricant chamber above the lubricant level.

[0014] At first glance, the design of a rotary vane pump with separate discharge, ventilation and compensation channels appears unnecessarily complex. However, any increase in manufacturing costs is generally outweighed by the associated advantages, since the separate design of the different channels (discharge, ventilation and compensation) allows the optimization of the associated channels for the functionality to be realized in each individual case, without usually having a significant adverse effect on the other functionality of the rotary vane pump, especially on the functionality of the other channels.

[0015] For example, a ventilation channel can be designed to (almost) optimally perform its associated ventilation function, particularly with respect to the arrangement and / or dimensions of its transfer chamber end, the arrangement and / or dimensions of its ventilation end, and / or other geometries (particularly cross-sectional shape, cross-sectional size, fluid throttle device, position, channel path, etc.). Due to its at least partially independent design, this usually does not adversely affect other functionalities, or at most only slightly. In the case of the ventilation function, it is particularly important to achieve the highest possible noise reduction on the one hand and ensure that the pumping behavior of the rotary vane pump is not excessively adversely affected (particularly with respect to the achievable low pressure, efficiency losses due to the incoming fluid, etc.). In this context, for the sake of completeness, it should be noted that a compromise may sometimes be found between optimal noise reduction and the lowest possible pumping efficiency losses. However, this compromise primarily concerns the ventilation functionality itself / ventilation channel itself, and not the remaining channels and their functionality.

[0016] What has been said above with respect to the ventilation channel can equally be applied to other channels, in particular the exhaust channel and / or the compensation channel. In particular, the exhaust channel usually requires a particularly effective pumping performance with respect to the fluid to be transferred (especially if the fluid to be transferred is being discharged from the transfer chamber). In this case, a sufficiently large cross-sectional area must be selected for good transfer performance. However, a too large exhaust channel can be disadvantageous in that it may reduce the achievable vacuum quality.

[0017] In particular, with regard to the compensation channel, the main concern is usually to achieve the fastest possible ventilation of the transfer chamber / rotor accommodation chamber when / after the rotary vane pump is switched off, in combination with the best possible sealing effect in the operating state of the rotary vane pump, and / or to achieve a sufficiently low inflow of lubricating oil into the transfer chamber / rotor accommodation chamber when / after the rotary vane pump is switched off. In principle, the ventilation ends of the ventilation channel can be in fluid contact with essentially any area. In particular, these can be areas that are mostly under atmospheric pressure. Fluid communication can occur not only with the surroundings (i.e., the outside), but also with certain (internal) areas of the rotary vane pump, in particular with those (internal) areas of the rotary vane pump that are essentially at ambient / atmospheric pressure (especially in the operating state of the rotary vane pump). This may be, for example, an area of ​​the lubricant chamber (or, if applicable, further the lubricant reservoir and / or lubricant supply chamber) that is (substantially) filled with gas, or an area of ​​the lubricant chamber (or, if applicable, further the lubricant reservoir and / or lubricant supply chamber) that is (substantially) filled with gaseous fluid.

[0018] For the sake of completeness, it is pointed out that if an excessive amount of lubricant oil enters the transfer chamber / rotor receiving chamber, it may require (excessively) high torque when restarting the rotary vane pump. Additionally or alternatively, this may result in damage to the rotary vane pump or at least increased wear, which is obviously undesirable. If an excessive amount of lubricant oil enters the rotor receiving chamber, it may also lead to leakage of lubricant oil into the intake channels of the rotary vane pump, which may cause oil contamination of the vacuum area or vacuum equipment, if applicable.

[0019] In principle, any kind of valve design is possible: in particular passive valves, check valves, disc valves, seat valves, etc. When designing a valve device, the combination of low-cost construction, the best possible sealing effect, a long service life, and the highest possible maximum switching frequency must be taken into account.

[0020] In particular, the compensation end of the compensation channel and / or the ventilation end of the ventilation channel and / or the discharge end of the discharge channel can be arranged in an area of ​​the lubricant chamber substantially adjacent to the rotor accommodating chamber or the transfer chamber. In particular, the associated ends can be formed in a wall separating the lubricant chamber from the rotor accommodating chamber or the transfer chamber. In this way, substantially straight and / or relatively short compensation channels, ventilation channels or discharge channels can be realized. This can facilitate a particularly simple construction, but can also be functionally advantageous.

[0021] In particular, the transfer chamber ends of the ventilation channels and / or the compensation channels of the rotary vane pump can open directly into the transfer chamber of the rotary vane pump. In other words, separate openings (separate from each other) are provided for the separate channels (ventilation channel, compensation channel, and / or discharge channel) leading to the transfer chamber, or, in other words, non-coincident openings or non-converging channels are provided, and have a common transfer chamber opening / end leading to the transfer chamber with a common channel portion. The same applies to the transfer chamber ends of the discharge channels adjacent to the transfer chamber. Individual design allows each transfer chamber end, in particular their arrangement, cross-sectional shape, and cross-sectional size, to be optimized for the respective purpose. Initial tests have shown, for example, that it is advantageous to arrange each transfer chamber end at different positions, in particular along the circumferential direction of the rotor receiving chamber / transfer chamber, i.e., in particular at slightly offset positions. For example, while locating the transfer chamber ends of the ventilation channels close to the dead center can achieve particularly effective noise reduction in combination with high efficiency of the rotary vane pump, it is desirable to locate the transfer chamber ends of the compensation channels some distance away from the dead center. Initial testing has shown that the transfer chamber ends of the ventilation channels (and, if necessary, the transfer chamber ends of the compensation channels, additionally or alternatively) should be located in the last third, preferably the last quarter, of the angular range of each transfer chamber that results when one side of each transfer chamber coincides with the dead center. For example, if there are three transfer chambers in the rotor-accommodating area and the transfer chamber ends of the associated channels are to be located in the last third, the transfer chamber ends should be located an angular range of 360° × 1 / 3 × 1 / 3 = 40° before the dead center. For four transfer chambers, this results in an angular range of 360° × 1 / 4 × 1 / 3 = 30° before the dead center. Additionally or alternatively, different arrangements of different transfer chamber ends (or portions thereof) in the axial direction may be provided, particularly to allow separation of different transfer chamber ends despite (substantially) equal or only slightly different arrangements along the circumferential direction of the rotor accommodating chamber.Additionally or alternatively, it is also conceivable that at least some of the transfer chamber ends are arranged at (substantially) the same height in the circumferential and / or axial direction. For the sake of completeness, it is of course noted that at least some of the channels can also be designed such that the associated channels are grouped away from the transfer chamber / rotor receiving chamber, resulting in a more or less common transfer chamber end / transfer chamber opening. The latter design form can result in a particularly simplified structure, smaller installation space requirements, and / or increased functionality of the rotary vane pump in question.

[0022] It is further proposed that in the rotary vane pump, the compensation channel is arranged so that it opens into the lubricant chamber completely below the lubricant level in the lubricant chamber when the rotary vane pump is in operation, and preferably opens into the lubricant chamber at least partially, preferably at least substantially completely above the lubricant level when the rotary vane pump is in a resting state. Such a design, in particular in combination with high airtightness of the compensation channel when the rotary vane pump is in operation, can enable good ventilation efficiency of the transfer chamber / rotor accommodation chamber after shutdown of the rotary vane pump. Furthermore, to maintain and possibly increase the effectiveness of the rotary vane pump, the amount of fluid flowing into the transfer chamber / rotor accommodation chamber (particularly the lubricant, but also the external fluid and / or the fluid to be transported, as well as a mixture of different fluids, such as a mixture of lubricant and the fluid to be transported) can be kept as low as possible. If, as is preferably suggested, in the rest state (especially immediately after switching off or shutting down the rotary vane pump) the compensation end of the compensation channel opens into the lubricant chamber above the lubricant level, a particularly fast ventilation of the transfer chamber / rotor accommodating chamber can be achieved and / or the amount of lubricant entering the transfer chamber / rotor accommodating chamber can be minimized, which are generally desirable features in rotary vane pumps.

[0023] It is further proposed to design the rotary vane pump so that the ventilation end of the ventilation channel opens into the lubricant chamber. The ventilation end of the ventilation channel can preferably open into the lubricant chamber above the lubricant level, particularly above the lubricant level during the rotary vane pump's operating state. In other words, the ventilation end of the ventilation channel can preferably open into a region of the lubricant chamber that is (at least substantially) filled with gas or (at least substantially) with a gaseous fluid. This effectively prevents unwanted contamination of the surrounding (external) space with lubricant. It is also advantageous to reduce the amount of lubricant lost from the rotary vane pump. In this context, it should be noted that any lubricant (e.g., in the form of a lubricant mist) transported from the lubricant chamber into the transfer chamber / rotor housing chamber by the ventilation channel generally poses no problems and, in particular, is, in principle, negligible compared to the amount of lubricant introduced via the compensation channel (although the amount of lubricant entering the transfer chamber / rotor housing chamber through the compensation channel is relatively small due to the proposed rotary vane pump design).

[0024] Furthermore, a design of the rotary vane pump is proposed in which the discharge channel is arranged to open into the lubricant chamber at least partially, preferably at least substantially completely, below the lubricant level in the lubricant chamber in the operating state of the rotary vane pump. This applies in particular to the operating state of the rotary vane pump, but may also apply to the resting state of the rotary vane pump. In this way, the valve device can usually be particularly tight, which can increase the effectiveness of the rotary vane pump and / or allow the use of a relatively simply constructed and / or inexpensively manufactured valve device.

[0025] It is further proposed that the lubricant chamber of the rotary vane pump preferably has a lubricant reservoir adjacent to the discharge channel and a lubricant storage area, the lubricant reservoir and the lubricant storage area being separated from each other by a partition wall, preferably an overflow partition wall. This relatively simple further development allows the lubricant level in the lubricant reservoir to be lowered particularly quickly when the rotary vane pump is switched off, and thus allows the compensation end of the compensation channel to be brought partially / almost completely above the lubricant level (by lowering the lubricant level) particularly quickly. In particular, this significantly reduces the amount of lubricant entering the rotor-accommodating chamber via the compensation channel. Providing a lubricant storage area separate from the lubricant reservoir allows the lubricant supply (which can be transferred to the relevant areas of the rotary vane pump, for example, via a supply pump, for lubricating various components) to be selected to be particularly large, thereby allowing the rotary vane pump to operate for particularly long periods without the need to replenish the lubricant. In particular, this allows for longer maintenance intervals and / or reduces the possibility of damage due to lubricant loss. Another advantageous feature of the partition is that it usually defines to a large extent the lubricant level in the lubricant tank, especially in the operating state of the rotary vane pump (excess lubricant will overflow the partition and flow into the lubricant storage area; it should be noted that the lubricant is usually replenished via the drain channel). In this way, the lubricant level relative to the compensation end of the compensation channel, the ventilation end of the ventilation channel and / or the drain end of the drain channel (first of all relative to the compensation end of the compensation channel) can be particularly easily and accurately defined both in the operating state and in the rest state of the rotary vane pump. For the sake of completeness, it is pointed out that the lubricant level in the lubricant tank is usually higher than the lubricant level in the lubricant storage area, especially in the operating state of the rotary vane pump, but also often in the switched-off state of the rotary vane pump.

[0026] The partition wall can have at least one outlet and / or at least one recess in the upper end area of ​​the partition wall. The number and size of the recesses and / or outlets in the upper end area of ​​the partition wall must be selected so that the amount of lubricant discharged through these recesses / outlets is compensated for by the lubricant subsequently transferred under all realistically expected operating conditions of the rotary vane pump. In principle, a safety margin must be taken into account. The outlet can be designed as a through-hole in the partition wall. The proposed design can facilitate a particularly rapid drop in the lubricant level in the lubricant reservoir area, especially when the rotary vane pump switches from an operating state to a resting state. This reduces the amount of lubricant entering the rotor chamber / transfer chamber when the rotary vane pump is switched off.

[0027] It is also proposed to provide at least one volume reduction device, in particular a bead device, in the lubricant chamber, in particular in the lubricant reservoir, particularly preferably in the upper filling level region of the lubricant chamber and / or lubricant reservoir. In this way, for example, the cross section of the lubricant reservoir can be reduced in its upper filling level region (particularly in the region of the upper end of the partition wall). The upper level range can be understood, in particular, as the range between the lubricant level when the rotary vane pump is switched on and the lubricant level when the rotary vane pump is switched off. This can further accelerate the decrease in the lubricant level during the transition of the rotary vane pump from an operating state to a resting state. Therefore, the amount of lubricant entering the rotor receiving chamber / transfer chamber can be further reduced. The bead device can be arranged, in particular, on the partition wall, in the region of its upper end. Additionally or alternatively, the partition wall can be curved so that the cross section of the lubricant reservoir tapers toward the top.

[0028] Furthermore, a rotary vane pump design is proposed in which the valve device is at least partially designed as a valve tongue device. In particular, the valve device or valve tongue device can have several valve tongue areas. This allows for a relatively simple and cost-effective design of the valve device. In particular, in conjunction with at least partial immersion of the valve device in the lubricant chamber / lubricant tank, a particularly high sealing effect of the valve device can usually be achieved.

[0029] When designing a rotary vane pump, it is possible, and often preferable, to provide multiple intake channels, exhaust channels, valve devices, valve tongue devices, ventilation channels, compensation channels, transfer chambers, rotors, and / or rotor accommodation chambers. In this way, the functionality of the rotary vane pump can usually be significantly improved. In particular, the pump performance, achievable pressure, noise after switching off / shutdown of the rotary vane pump, and / or ventilation can be improved. It should be noted, however, that a rotary vane pump can also have only one rotor accommodation chamber, one rotor, one transfer chamber, one intake channel, one exhaust channel, one valve device, one compensation channel, and / or one ventilation channel. However, it is also conceivable that one, several, or all of the mentioned elements can occur several times (in particular, two, three, four, five, or six times). In this context, mention may also be made of the possibility of "mixed combinations", such that a rotary vane pump with a rotor and a rotor receiving chamber may have, for example, three transfer channels, two intake channels, four discharge channels, one valve device (particularly a valve device with several valve areas, in particular valve tongue areas), one ventilation channel, and two compensation channels. Of course, other combinations are also conceivable.

[0030] It is also proposed that in the rotary vane pump, at least one ventilation channel and / or at least one compensation channel have at least one fluid flow restriction device, in particular at least one throttling device. This can further increase the functionality of the channel in question. Furthermore, if the fluid flow restriction device is designed to be variable and / or interchangeable (in each case, particularly with regard to the achievable fluid flow rate), the rotary vane pump can be particularly easily adapted to various applications / use cases. For example, by using different throttling devices, the rotary vane pump can be adapted for use with different lubricating oils (e.g., different viscosities) without the need for excessively expensive adaptation work.

[0031] In another possible design of the rotary vane pump, at least one valve device of the rotary vane pump is designed as a fully sealed valve device, in particular, in such a way that at least one valve tongue area of ​​the valve device is essentially free of recesses. In this way, the effectiveness of the rotary vane pump can usually be further increased. In particular, pumping losses and / or pressure / vacuum degradation can usually be avoided. Functionalities such as ventilation during operation to reduce noise and / or ventilation of the rotor chamber / transfer chamber of the rotary vane pump when the rotary vane pump is switched off are realized by devices (compensation chambers / ventilation channels) specially provided and designed for this purpose, which can be optimized for the functionality to be achieved in each case. In a sense, the proposed design can also be understood in the sense that the valve device is optimized or can be optimized depending on its intended use, i.e., it allows fluid to flow (substantially) only in one direction.

[0032] In another embodiment of the rotary vane pump, the dimensions of the rotary vane pump, particularly the volume of the lubricant chamber, and particularly preferably the volume of the lubricant reservoir, are selected so that the lubricant level reduction during the transition from the operating state of the rotary vane pump to the idle state is achieved by an initial lubricant transfer from the lubricant chamber and / or the lubricant reservoir into the transfer chamber / rotor-accommodating chamber via the compensation channel, and the maximum lubricant transfer (particularly in terms of volume) into the transfer chamber is dimensioned so that the restart of the rotary vane pump is not significantly, particularly not substantially, affected by the lubricant present in the transfer chamber. Additionally or alternatively, the maximum lubricant transfer (particularly in terms of volume) into the transfer chamber should be dimensioned so as to reduce, particularly minimize, or at least essentially prevent the release of lubricant into the intake channel area or into the intake channel. In this way, the functionality desired for the rotary vane pump during switch-off / shutdown (transition from the operating state of the rotary vane pump to the idle state of the rotary vane pump) can be achieved by means of a relatively simple and inexpensive implementation. In particular, the transferred lubricant should be in the smallest volume possible so that, when the rotary vane pump is restarted, an undesirably high drive torque is not required and / or wear is not increased and / or damage to the mechanical components (particularly the wall elements / sliders, etc.) is not caused (at least under realistically expected operating conditions).

[0033] In particular, it is proposed to design and arrange the rotary vane pump in such a way that the relative positioning of the lubricant level in the lubricant chamber and / or lubricant reservoir on the one hand and the compensation end of the discharge channel and / or compensation channel on the other hand is (exclusively) caused by changes in the lubricant level (height / level). Such changes in the lubricant level can be realized in particular by suitable dimensions of the lubricant chamber / lubricant reservoir. This makes it particularly easy to technically implement the desired functionality. In particular, for example, no mobile mechanical components need to be provided for this purpose.

[0034] In particular, it is proposed that in a rotary vane pump, at least one transfer chamber is at least partially delimited by a wall element that can shift and / or pivot relative to the rotor. In particular, the displaceability of the wall element (often called a slider) relative to the rotor can be realized by the wall element being displaceably mounted in a correspondingly formed receiving slot (often called a slider slot) in the rotor. It is therefore noted that mechanical wear can be reduced through the relative movement between the rotor and the wall element(s) by using a lubricant. Typically, this configuration results in 2, 3, 4, 5, 6, 7, 8, 9, 10, or more transfer chambers (in particular per rotor receiving area), although the above description is not necessarily limited to this embodiment.

[0035] It is further proposed that the ventilation channel of the rotary vane pump, and in particular the fluid flow restriction device of the ventilation channel, be dimensioned in such a way that, under the operating conditions of the rotary vane pump, noise reduction is achieved without significantly impairing the conveying rate of the rotary vane pump. This is also, in principle, a particularly desirable operating behavior for a rotary vane pump. The proposed design of the rotary vane pump presented herein allows this particularly desirable operating behavior of the rotary vane pump to be technically realized in a relatively simple manner.

[0036] It is further proposed that in a rotary vane pump, the compensation channel, and in particular the fluid flow restriction device of the compensation channel, be dimensioned such that sufficient ventilation of the transfer chamber is achieved during shutdown of the rotary vane pump without significant disruption of the operating state due to lubricant and / or the fluid to be transferred flowing back through the compensation channel. This is also a particularly desirable operating behavior for a rotary vane pump. Again, the rotary vane pump design presented herein makes it easy to achieve this desired operating behavior of the rotary vane pump in a relatively simple manner.

[0037] Further advantages, features, and capabilities of the present invention will become apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0038] [Figure 1] FIG. 1 is a schematic cross-sectional view of a rotary vane pump with a laterally located lubricant chamber. [Figure 2] FIG. 2 is an enlarged detail of FIG. 1 in the region of the exhaust channel, the ventilation channel and the compensation channel. [Figure 3] FIG. 3 is a side view of the area of ​​the rotary vane pump shown in FIG. 1 that includes a valve tongue device. [Figure 4] 4 is a side view of an overflow partition in the lubricant chamber of the rotary vane pump shown in FIG. 1. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0039] Shown in a schematic cross-section in Figure 1 is a rotary vane pump 1. Such rotary vane pumps 1 are known from their basic construction in the state of the art and are used in a variety of applications.

[0040] The rotary vane pump 1 has a housing 2, within which a cavity, or rotor-accommodating chamber 3, is formed. A rotor 4 is eccentrically offset within the rotor-accommodating chamber 3 and can be configured for rotational movement along a rotation axis 5. In the illustrated embodiment, the rotor 4 has three slide slots 6, each of which accommodates a wall element 7 (often referred to as a slide, vane, or slide blade) displaceably disposed relative to the rotor 4 so that the wall element 7 rotates with the rotor 4. Through rotation of the rotor 4 about the rotation axis 5, the wall element 7 is pressed against an inner wall 8 of the rotor-accommodating chamber 3 by centrifugal force. The use of a lubricating oil 10 significantly reduces wear in the rotary vane pump 1 by reducing mechanical friction between a front end 9 of the wall element 7 and the inner wall 8 of the rotor-accommodating chamber 3. At the same time, the lubricating oil film between the front end 9 of the wall element 7 and the inner wall 8 of the rotor-accommodating chamber 3 creates a seal, preventing the fluid to be pumped from passing through.

[0041] The wall element 7 divides the rotor accommodating chamber 3 (considering the rotor 4) into three transfer chambers 11, namely transfer chambers 11a, 11b and 11c. Depending on the current position and dead center 15 of the rotor 4, the transfer chamber 11c can be further divided into two sub-transfer chambers 11c, 11c' separated by the dead center. Due to the eccentric arrangement of the rotor 4 within the rotor accommodating chamber 3, the volume of the transfer chamber 11 changes periodically in the course of rotation of the rotor 4 of the rotary vane pump 1, thereby allowing the fluid to be transported.

[0042] The fluid to be transferred is drawn into one of the three transfer chambers 11 (currently transfer chamber 11a and possibly further transfer chamber 11c') via the inlet 12. The boundaries of the transfer chambers 11 in question are, as already mentioned, defined by two adjacent wall elements 7. Due to the initial expansion of each transfer chamber 11, the fluid to be transferred is sucked into the respective transfer chamber 11 (transfer chamber 11a). After each transfer chamber 11 is separated from the inlet 12 by the rotation of the rotor 4 from a specific angular position, its volume is reduced again due to the shape of the rotor receiving chamber 3 and the rotor 4 eccentrically arranged therein, compressing the fluid contained therein (transfer chamber 11b). From the specific angular position of the rotor 4 or each transfer chamber 11, a fluid connection to the discharge channel 13 is established, and the fluid to be transferred is discharged from the transfer chamber 11 via the discharge channel 13 into the lubricant chamber 14 (transfer chamber 11c). The discharge of fluid into the lubricant chamber 14 is carried out via a valve tongue device 21, which opens when the pressure in the transfer chamber 11 is slightly higher than the pressure in the lubricant chamber 14 (usually 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 accommodating chamber 3 adjacent to the discharge channel 13 from the area of ​​the rotor accommodating chamber 3 adjacent to the inlet 12.

[0043] The lubricant chamber 14 is connected via a flange area 16 to an area of ​​the housing 2 of the rotary vane pump 1 in which the rotor receiving chamber 3 with the rotor 4 is formed. In this embodiment, the lubricant chamber 14 has two different areas: a lubricant tank 17 arranged adjacent to the discharge channel 13 and a separately designed lubricant storage area 18. The lubricant tank 17 and the lubricant storage area 18 are separated from each other by a partition wall, which is designed as an overflow partition wall 19.

[0044] The discharge end 20 facing the lubricant reservoir 17 is connected to the lubricant reservoir 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, for example by means of a screw 22. In the illustrated embodiment, the valve tongue device 21 has four elastic valve tongue areas 23 (see also the diagram in FIG. 3 ), which cover each discharge end 20 of the discharge channel 13 and are also arranged adjacent to one another in the axial direction of the rotation axis 5 of the rotor 4. The elastic valve tongue areas 23 allow the fluid transported by the rotary vane pump 1 to flow only from the rotor receiving chamber 3 to the lubricant reservoir 14, but not in the reverse direction.

[0045] In the case under consideration, the rotary vane pump 1 is designed such that the discharge end 20 of the discharge channel 13 opens into the lubricant reservoir 17 in the operating state of the rotary vane pump 1 below the lubricant level 24. This has the advantage that the lubricant 10 in the lubricant reservoir 17 exerts a certain fluid pressure on the elastic valve tongue area 23, and the discharge end 20 of the discharge channel 13 is reliably closed (fluid-tight) by the valve tongue area 23. As a result, the atmospheric pressure in the lubricant chamber 14 naturally imposes a pressure on the lubricant 10 in the lubricant reservoir 17. Furthermore, the lubricant 10 provides a certain degree of sealing of any gaps and cracks that may be present, resulting in a particularly tight seal of the valve tongue device 21.

[0046] As can be seen in particular from the enlarged view of Figure 2, in the illustrated embodiment of the rotary vane pump 1, in addition to the discharge channel 13, there is also a ventilation channel 26, which in this case is completely separate from the discharge channel 13, and (in this case) two compensation channels 29, the compensation channels 29 also being designed completely separate from the discharge channel 13 and the ventilation channel 26.

[0047] The ventilation channel 26 has a ventilation device 27 that opens into the lubricant chamber 14 (or lubricant tank 17) above the lubricant level 24 when the rotary vane pump 1 is in operation. The transfer chamber end 28 of the ventilation channel 26 is located in a suitable position within the rotor-accommodating chamber 3, preferably directly adjacent to the dead center 15. The ventilation channel 26 allows small amounts of air or fluid (especially gaseous fluid) present in the lubricant chamber 14 to flow into the compression area of ​​the rotor-accommodating chamber 3. This reduces noise generation, especially when the rotor 4 is rotating at a critical speed. The ventilation openings 26 can be optimized for noise reduction, thereby achieving significant noise reduction with relatively little construction effort, without significantly affecting other advantageous properties of the rotary vane pump 1 (described in more detail below).

[0048] In particular, it is possible to provide the ventilation channel 26 with a suitably dimensioned throttle valve 32. Furthermore, the throttle valve 32 can also be exchangeable, so that the rotary vane pump 1 can be quickly adapted (even retroactively) to different operating environments and different purposes.

[0049] Furthermore, in the exemplary embodiment shown here, two compensation channels 29 are provided, which are arranged at the same height but axially offset from one another (relative to the axis of rotation 5 of the rotor 4) (see also the illustration in FIG. 3). Of course, a different number of compensation channels 29 (and, incidentally, the same for the ventilation channels 26) can also be provided.

[0050] The compensation end 30 of the compensation channel 29 is positioned so that it is directly below the lubricant level 24 in the lubricant reservoir 17 when the rotary vane pump 1 is in operation. As a result, a certain degree of sealing effect is achieved by the lubricant 10 in the lubricant reservoir 17, and only a small (net) fluid flow rate (if any) occurs through the outlet channel 29 during operation of the rotary vane pump 1. This applies both to the fluid flow transferred out of the rotor accommodating chamber 3 in the direction of the lubricant reservoir 14, and to the fluid (particularly the lubricant 10) flowing out of the lubricant reservoir 14 or the lubricant reservoir 17 in the direction of the rotor accommodating chamber 3.

[0051] What is particularly noteworthy about the arrangement of the compensation ends 30 of the outlet channels 29 is that they are located completely below the lubricant level 24 in the operating state of the rotary vane pump 1, but only slightly below the lubricant level 24 in the operating state of the rotary vane pump 1. This has the consequence that the compensation channels 29 need to be exposed as quickly as possible after a shutdown of the rotary vane pump 1 (whether intentional or not). Therefore, when the rotary vane pump 1 is switched off, the lubricant level in the lubricant tank 17 needs to drop as quickly as possible to the lubricant level 34 (shown by the dashed line in Figures 1 to 3). This will be explained in more detail below.

[0052] In the operating state of the rotary vane pump 1, the lubricant-rich fluid to be transferred (suction of the fluid to be transferred via the inlet port 12) is transferred from the transfer chamber 11 (in this case, transfer chamber 11c) located adjacent to the discharge channel 13 into the discharge channel 13 by the periodically expanding and contracting transfer chamber 11. The resulting pressure pushes the elastic valve tongue area 23 of the valve tongue device 31 away from the wall of the flange area 16, so that the lubricant-fluid mixture enters the lubricant reservoir 17 or the oil chamber 14. This continuous flow of the lubricant-fluid mixture (and thus further lubricant 10) maintains the lubricant level 24 in an upper range in the operating state of the rotary vane pump 1. The upper lubricant level 24 is essentially defined by the upper end 35 of the overflow partition 19. The functions of the optional recess 36 in the area of ​​the upper end 35 of the overflow partition 19 and the optional outlet 37 in the overflow partition 19 will be described later. In either case, the recesses 36 and the outlets 37 (if present) are dimensioned in number and size so that the lubricant level 24 in the operating state of the rotary vane pump 1 remains in the area of ​​the upper end 35 of the overflow partition 19 in all realistically expected operating states of the rotary vane pump 1, whereby a rise in the lubricant level 24 above the upper end 35 of the overflow partition 19 occurs by an overflow 38 of the lubricant 10 (shown by arrows 38 in Figures 1 and 2), which causes the lubricant 10 to flow from the lubricant tank 17 into the lubricant storage area 18 of the lubricant chamber 14.

[0053] Lubrication of the rotary vane pump 1, in particular in the area of ​​the rotor 4 or in the rotor receiving chamber 3, can be achieved by a lubricating oil pump, not shown here, which releases lubricating oil 10, for example, in the area of ​​the intake port 12 of the rotary vane pump. Such lubricating oil pumps and such lubrication of rotary vane pumps 1 are known per se in the prior art.

[0054] When the rotary vane pump 1 stops (for example, due to an intentional shutdown process, but also due to an unintentional failure), air or fluid (e.g., primarily gaseous fluid) is drawn from the lubricant chamber 14 into the rotor accommodating chamber 3 via the ventilation channel 26. Furthermore, the lubricant 10 first flows into the rotor accommodating chamber 3 from the lubricant reservoir 17 via the compensation channel 29. Since the lubricant reservoir 17 is not "topped up" with the lubricant 10 (via the drain channel 13) when the rotary vane pump 1 stops, the initial lubricant level 24 in the operating state of the rotary vane pump 1 drops rapidly to a lower lubricant level 34 in the switched-off state of the lubricant pump 1. Therefore, the compensation end 30 of the compensation channel 29 is now exposed, so that air or substantially gaseous fluid is drawn from the lubricant chamber 14 into the rotor accommodating chamber 3. This allows the pressure in the rotor accommodating chamber 3 to be equalized particularly quickly. The rotor receiving chamber 3 can therefore be brought to ambient pressure (typically atmospheric pressure) particularly quickly, ensuring that only a minimal amount of lubricant enters the rotor receiving chamber 3. This is an advantageous way of preventing the rotor receiving chamber 3 from filling up with lubricant.

[0055] The rapid drop in the lubricant level from the operating state level 24 to the switch-off level 34 can be accelerated by an optional recess 36 in the area of ​​the upper end 35 of the overflow partition 19 and / or by outlets 37 in the overflow partition 19. The number and size of the recesses 36 and / or outlets 37 can be selected so that the amount of lubricant discharged through these recesses / openings is compensated (usually plus a safety margin) under all operating conditions that are realistically expected in the operating state of the rotary vane pump 1. In order to make the rotary vane pump 1 adaptable to various applications and / or operating conditions, the recesses 36 and / or outlets 37 can be designed to be reversibly closable, for example by providing an internal thread (especially in the case of the outlets 37) or by the possibility of a slip-on discharge edge (especially in the case of the recesses 36 in the area of ​​the upper end 35).

[0056] Furthermore, in the example embodiment shown, a bead 39 is also optionally fitted in the area of ​​the upper end 35 of the overflow partition wall 19, which results in a tapered cross section (horizontal cross section in Figures 1 and 2) such that a smaller volume of lubricant 10 is sufficient to reduce the lubricant level 24 in the operating state of the rotary vane pump 1 to the lubricant level 34 in the switched-off state (compared to the situation without the bead 39). The bead 39 also increases the effectiveness of the recess 36 and / or the outlet 37 (if present).

[0057] Furthermore, it is possible to take only individual elements of the detailed example embodiments of the rotary vane pump 1 described herein (or even a particular subset of the described features) and combine them with the general description of the presently proposed rotary vane pump.

Claims

1. A rotary vane pump (1) for transporting a fluid to be transported, a housing (2) with a rotor-accommodating chamber (3); a lubricant chamber (14); a rotor (4) eccentrically arranged within said rotor receiving chamber (3), said rotor (4) defining at least one transfer chamber (11) whose volume varies periodically as said rotor (4) rotates; an intake channel (12) for supplying the fluid to be transferred into at least one of the transfer chambers (11); a discharge channel (13) for discharging the fluid to be transferred from at least one of the transfer chambers (11) in the direction of the lubricant chamber (14); and a valve device (21) is provided between the drain channel (13) and the lubricant chamber (14) for preventing a backflow of fluid, in particular lubricant and / or the fluid to be transferred, from the lubricant chamber (14) into at least one of the transfer chambers (11); The rotary vane pump (1) is designed and installed so that the discharge channel (13) is arranged to open into the lubricant chamber (14); At least one ventilation channel (26) is fluidly connected to at least one of said transfer chambers (11) by a transfer chamber end (28) and to at least one chamber external to said transfer chamber (11) by a ventilation end (27); at least one compensation channel (29) fluidly connected to at least one of said transfer chambers (11) by a transfer chamber end (31) and to said lubricant chamber (14) by a compensation end (30); The rotary vane pump (1) is characterized in that the compensation end (30) is designed and installed to open into the lubricant chamber (14) below a lubricant level (24) when the rotary vane pump (1) is in an operating state, and to open into the lubricant chamber (14) above a lubricant level (34) when the rotary vane pump (1) is in a rest state.

2. 2. The rotary vane pump (1) according to claim 1, characterized in that the transfer chamber end (28) of the ventilation channel (26) and / or the transfer chamber end (30) of the compensation channel (29) open directly into the transfer chamber (11) of the rotary vane pump (1).

3. 3. A rotary vane pump (1) according to claim 1 or 2, characterized in that the compensation channel (29) is arranged so that in an operating state of the rotary vane pump it opens into the lubricant chamber (14) completely below the lubricant level (24) of the lubricant chamber (14), and preferably in a rest state of the rotary vane pump (1) it opens into the lubricant chamber (14) at least partially, preferably at least substantially completely, above the lubricant level (34).

4. 4. A rotary vane pump (1) according to claim 1, wherein the ventilation end (27) of the ventilation channel (26) opens into the lubricating oil chamber (14).

5. 5. A rotary vane pump (1) according to claim 1, characterized in that the discharge channel (13) is arranged to open into the lubricant chamber (14) at least partially, preferably at least substantially completely, below the lubricant level (24) in the lubricant chamber (14) in an operating state of the rotary vane pump (1).

6. 6. The rotary vane pump (1) according to any one of claims 1 to 5, characterized in that the lubricant chamber (14) comprises a lubricant tank (17) adjacent to the discharge channel (13) and a lubricant storage area (18), the lubricant tank (17) and the lubricant storage area (18) being preferably separated from each other by a partition wall, preferably an overflow partition wall (19).

7. 7. A rotary vane pump (1) according to claim 6, characterized in that the partition wall (19) has at least one outlet (37) and / or at least one recess (36) in the region of the upper end (35) of the partition wall (19).

8. 1. A rotary vane pump (1) according to any one of claims 1 to 7, in particular claim 6 or 7, characterized in that at least one volume reduction device, in particular a bead device (39), is provided in the lubricant chamber (14), in particular in the lubricant reservoir (17), particularly preferably in the upper filling level region of the lubricant chamber (14) and / or the lubricant reservoir (17).

9. A rotary vane pump (1) according to any one of claims 1 to 8, characterized in that the valve device (21) is designed as a valve tongue device (23) in at least some areas.

10. 10. A rotary vane pump (1) according to any one of claims 1 to 9, characterized by a plurality of intake channels (12), and / or discharge channels (13), and / or valve devices (21), and / or valve tongue devices (23), and / or ventilation channels (26), and / or compensation channels (26), and / or transfer chambers (11), and / or rotors (4), and / or rotor accommodation chambers (3).

11. 11. A rotary vane pump (1) according to any one of claims 1 to 10, characterized in that at least one ventilation channel (26) and / or at least one compensation channel (26) comprises at least one fluid flow restriction device, in particular at least one throttling device (32, 33).

12. A rotary vane pump (1) according to any one of claims 1 to 11, in particular according to any one of claims 9 to 11, characterized in that at least one valve device (21) is designed as a fully sealing valve device, in particular at least one valve tongue device (23) is designed in a manner that is substantially free of recesses.

13. 10. The rotary vane pump (1) according to claim 1, wherein the dimensions of the rotary vane pump (1), in particular the volume of the lubricant chamber (14), and particularly preferably the volume of the lubricant reservoir (17), are selected in such a way that a drop in the lubricant level (24) during the transition of the rotary vane pump (1) from the operating state to the resting state is achieved by an initial lubricant transfer from the lubricant chamber (14) and / or the lubricant reservoir (17) into the transfer chamber (11) via the compensation channel (29), and wherein the maximum lubricant transfer into the transfer chamber (11) is dimensioned in such a way that the lubricant present in the transfer chamber (11) does not impair the restart of the rotary vane pump (1).

14. 13. A rotary vane pump (1) according to claim 1, in particular claim 6, characterized in that the pump (1) is designed and installed in such a way that a relative positioning of the lubricant level (24, 34) in the lubricant chamber (14) and / or in the lubricant reservoir (17) on the one hand and the discharge channel (13) and / or the compensation end (30) of the compensation channel (29) on the other hand is caused by a change in the lubricant level (24, 34).

15. A rotary vane pump (1) according to any one of claims 1 to 14, characterized in that at least one of the transfer chambers (11) is at least partially delimited by a wall element (7) which is slidable and / or pivotable relative to the rotor (4).

16. A rotary vane pump (1) according to any one of claims 1 to 15, in particular any one of claims 11 to 15, characterized in that the ventilation channel (26), in particular the fluid flow restriction device (32) of the ventilation channel (26), is dimensioned such that, in an operating state of the rotary vane pump (1), noise reduction is achieved without significant impairment of the transport capacity of the rotary vane pump (1).

17. 10. A rotary vane pump (1) according to any one of claims 1 to 16, in particular any one of claims 11 to 16, characterized in that the compensation channel (29), in particular the fluid flow restriction device (33) of the compensation channel (29), is dimensioned in such a way that sufficient ventilation of the transfer chamber (11) is achieved during shutdown of the rotary vane pump (1) without significant disturbance of the operating state due to lubricant oil and / or the fluid to be transferred flowing back through the compensation channel (29).

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