Improved sliding vane rotary pump
Patent Information
- Application Number
- EP2022800246
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2022-10-10
- Publication Date
- 2025-08-20
AI Technical Summary
Rotary vane pumps suffer from constant noise and issues with lubricant ingress during shutdown, leading to increased operating noise, mechanical wear, and potential damage when restarted.
A rotary vane pump design featuring separate discharge, ventilation, and compensation channels, with optimized geometry and placement to prevent lubricant backflow and ensure efficient ventilation and sealing, reducing noise and mechanical stress.
The design achieves significant noise reduction and maintains pump effectiveness while minimizing lubricant ingress and mechanical wear, ensuring reliable operation and extended maintenance intervals.
Smart Images
Figure 1.1
Abstract
Description
[0001] Improved rotary vane pump
[0002] The invention relates to a rotary vane pump for conveying a fluid to be conveyed.
[0003] Rotary vane pumps have a housing with a cavity in which a rotatable rotor is eccentrically arranged. Typically, slot-like recesses (often referred to as vane slots) are formed in the rotor, in which wall elements (so-called vanes) are movably, in particular displaceably, arranged. In a large number of designs, the wall elements / vanes are pressed against an inner wall of the housing cavity (rotor receiving chamber) due to centrifugal force during rotation of the rotor. The wall elements thus form one or more delivery chambers, with the volume of the delivery chamber(s) varying cyclically during rotation of the rotor. By means of suitably arranged intake and discharge channels, a fluid to be delivered by the rotary vane pump can be conveyed from an intake channel to a discharge channel.
[0004] A lubricant stored in a lubricant chamber of the rotary vane pump is used to lubricate the mechanically moving parts. Another function of the lubricant is to provide additional sealing between the inner wall of the housing and the wall elements, between the wall elements and the rotor, and between other components of the rotary vane pump.
[0005] Rotary vane pumps as such are well-known in the art and are used in a wide variety of applications. A typical application for such rotary vane pumps is the generation of a vacuum, for example, in scientific applications (in the latter case, usually as one link in a chain of different pump types, with rotary vane pumps typically being used to generate a so-called forevacuum or rough vacuum). Although rotary vane pumps have proven themselves and are widely used, they still have certain disadvantages.
[0006] A frequently criticized disadvantage of rotary vane pumps is their constant noise. It's easy to understand why many users would welcome a reduction in this operating noise.
[0007] Another problem arises when shutting down rotary vane pumps (whereby the shutdown can be planned – for example, due to user intervention – or it can occur unplanned, for example, as a result of a malfunction). Typical designs of rotary vane pumps tend to suck lubricant into the rotor housing or pumping chambers. The sucked-in lubricant volume can then cause problems when the rotary vane pump is restarted, in particular causing increased operating noise, requiring increased drive torque, and / or causing increased mechanical resistance. The latter can lead to increased mechanical wear and, under unfavorable conditions, even damage to the rotary vane pump.It is readily apparent that, due to the problems described above, as well as other problems not described in detail here, there is still a need for improvements in the design of rotary vane pumps. Accordingly, it is not surprising that a number of possible improvements have already been proposed in the prior art.
[0008] WO 2013 / 139570 A2, for example, proposes a vacuum rotary vane pump in which a valve device is arranged between the discharge channel of the delivery chamber and the lubricant chamber of the rotary vane pump to prevent fluid from flowing back from the lubricant chamber into the delivery chamber. The use of a compensation channel is proposed, which is connected to the discharge channel and the lubricant chamber and is integrated into the valve device. This is intended to quickly equalize the pressure in the delivery chamber when the rotary vane pump is switched off, so that the delivery chamber is quickly brought to atmospheric pressure, thereby preventing the delivery chamber from filling with lubricant via the lubricant supply. A different design for such a compensation channel between the delivery chamber and the lubricant is proposed in WO 2007 / 006666 A1.
[0009] EP 3 470 678 A1 proposes to provide a compensation channel between the delivery chamber and the lubricant chamber of a rotary vane pump, wherein an opening of the compensation channel is arranged in the region of an overflow partition wall of the lubricant chamber.
[0010] Although these proposals have some advantages, there is still a need for further improvements.
[0011] The object of the present invention is therefore to propose a rotary vane pump for conveying a fluid to be conveyed, which has an improved operating behavior.
[0012] A rotary vane pump for conveying a fluid to be conveyed having the features of claim 1 solves this problem.
[0013] A rotary vane pump for conveying a fluid to be conveyed is proposed, which has a housing with a rotor receiving space, a lubricant chamber, a rotor arranged eccentrically in the rotor receiving space, an intake channel for supplying the fluid to be conveyed into the conveying chamber, and an exhaust channel for expelling the fluid to be conveyed from the conveying chamber in the direction of the lubricant chamber. The rotor is arranged eccentrically in the rotor receiving space m in such a way that at least one conveying chamber is created, the volume of which varies cyclically during rotation of the rotor. A valve device is provided between the exhaust channel and the lubricant chamber to prevent fluid, in particular lubricant and / or fluid to be conveyed, from flowing back from the lubricant chamber into the conveying chamber. The rotary vane pump is designed and configured such that the exhaust channel opens into the lubricant chamber.The rotary vane pump has at least one ventilation channel, which is fluidly connected to the delivery chamber at one end of the delivery chamber and fluidly connected to a space outside the delivery chamber at one ventilation end. Furthermore, the rotary vane pump has at least one compensation channel, which is fluidly connected to the delivery chamber at one end of the delivery chamber and fluidly connected to the lubricant chamber at one compensation end. The rotary vane pump is designed and configured such that, when the rotary vane pump is in operation, the compensation end of the compensation channel opens into the lubricant chamber below the lubricant level. When the rotary vane pump is in a resting state (or switched off state), 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 channel, ventilation channel, and equalization channel appears unnecessarily complex. However, the increased manufacturing effort – which is indeed a given – is generally more than offset by the associated advantages. This is because the separate design of the different channels (discharge channel, ventilation channel, equalization channel) allows for optimization of the respective channel for the respective functionality to be implemented, without this generally having any significant adverse effects on the other functionalities of the rotary vane pump, especially on the functionalities of the remaining channels.
[0015] To give an example: the ventilation duct can be designed, particularly with regard to the placement and / or dimensioning of its conveying chamber end, the placement and / or dimensioning of its ventilation end, and / or its other geometry (in particular, cross-sectional shape, cross-sectional size, fluid throttling devices, position, channel routing, and the like), so that it can (largely) optimally perform its associated ventilation function. Due to its at least partially separate design, this usually has no, or at most minor, adverse effects on the other functionalities.With the aeration function, it is particularly important to ensure that, on the one hand, the best possible noise reduction is achieved, while, on the other hand, the pumping behavior of the rotary vane pump is not unduly adversely affected (particularly with regard to the achievable negative pressure, efficiency losses due to inflowing fluid, and the like). In this context, for the sake of completeness, it should be noted that a compromise may have to be found between optimal noise reduction and the lowest possible loss of pump efficiency. However, this compromise largely affects only the aeration functionality as such / the aeration channel as such, but not the other remaining channels and their functionalities.
[0016] What has been said above regarding the ventilation channel can also apply analogously to the other channels, in particular to the discharge channel and / or the equalization channel. In particular, the discharge channel typically requires particularly effective pumping performance with respect to the fluid to be conveyed (especially when discharging the fluid to be conveyed from the conveying chamber). A sufficiently large cross-sectional area must be selected to ensure good conveying performance. However, an excessively large discharge channel can be disadvantageous, for example, in that the achievable vacuum quality may be reduced.
[0017] Particularly with regard to the compensation channel, the primary concern is generally the best possible sealing effect during the rotary vane pump's operating state, combined with the fastest possible venting of the delivery chamber / rotor receiving chamber during or after the rotary vane pump is shut down, and / or a sufficiently small lubricant volume flowing into the delivery chamber / rotor receiving chamber during / after the rotary vane pump is shut down. The vent end of the vent channel can, in principle, be in fluidic contact with essentially any desired area. In particular, these areas can be areas that are largely under atmospheric pressure.This can result in fluidic communication with the environment (i.e., to 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 an operating state of the rotary vane pump). This can, for example, be an area of the lubricant chamber (or possibly also the lubricant bath and / or the lubricant storage chamber) that is (essentially) filled with a gas or a (essentially) gaseous fluid.
[0018] For the sake of completeness, it should be noted that an excessive amount of lubricant flowing into the discharge chamber / rotor receiving chamber can result in (excessively) high torque being required when restarting the rotary vane pump. Additionally or alternatively, damage or at least increased wear of the rotary vane pump can occur, which is naturally undesirable. An excessive amount of lubricant flowing into the rotor receiving chamber can also lead to lubricant leaking into the intake channel of the rotary vane pump, potentially contaminating vacuum areas or vacuum equipment.
[0019] In principle, any type of valve design is possible. In particular, passive valves, check valves, poppet valves, seat valves, and / or similar are considered. When designing the valve mechanism, particular attention should be paid to a combination of cost-effective construction, the highest possible sealing effect, long service life, and a high maximum possible switching frequency.
[0020] In particular, it is possible to arrange 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 in a region of the lubricant chamber that is essentially adjacent to the rotor receiving chamber or the delivery chamber. In particular, the respective ends can be formed in a wall that separates the lubricant chamber from the rotor receiving chamber or the delivery chamber. This makes it possible to create a largely straight and / or relatively short compensation channel, ventilation channel or discharge channel. This can, in particular, promote a simple design, but can also be functionally advantageous. In particular, it is possible for the delivery chamber end of the ventilation channel and / or the delivery chamber end of the compensation channel in the rotary vane pump to open directly into the delivery chamber of the rotary vane pump.In other words, separate openings (separate openings) leading to the conveying chamber are provided for the separate channels (ventilation channel, equalization channel, and / or discharge channel). In other words, openings are provided that do not coincide, or channels are provided that do not merge, and, with a common channel section, have a common conveying chamber opening / conveying chamber end leading to the conveying chamber. The same also applies to the conveying chamber end of the discharge channel located adjacent to the conveying chamber. The separate design makes it possible to optimize the respective conveying chamber ends, in particular their placement, cross-sectional shape, and cross-sectional size, for the respective purpose.For example, initial tests have shown it to be advantageous if the respective discharge chamber ends are positioned at different locations, particularly along a circumferential direction of the rotor receiving chamber(s), i.e., at slightly offset locations. For example, positioning the discharge chamber end of the ventilation channel near the dead center can achieve particularly effective noise reduction combined with high efficiency of the rotary vane pump, while the discharge chamber end of the compensation channel, for example, is preferably positioned somewhat further from the dead center.Initial tests have shown that in particular the conveying chamber end of the ventilation duct (if necessary additionally or alternatively also the conveying chamber end of the compensation duct) should be located in the last third, preferably in the last quarter of the angular range of the respective conveying chamber, which results when one side of the respective conveying chamber coincides with the dead center. So if, for example, there are three conveying chambers in a rotor receiving area and the conveying chamber end of the respective duct is to be within the last third, the conveying chamber end should be arranged in an angular range of 360° ■ 1 / 3 ■ 1 / 3 = 40° before the dead center. With four conveying chambers this would accordingly result in an angular range of 360° ■ 1 / 4 ■ 1 / 3 = 30° before the dead center.Additionally or alternatively, a different placement of the different conveying chamber ends (or some of them) in the axial direction can also be used, in particular to enable a separation of the different conveying chamber ends despite (essentially) identical or only slightly different placements along the circumferential direction of the rotor receiving chamber. Furthermore, additionally or alternatively, it is also conceivable that at least some of the conveying chamber ends are arranged at (essentially) the same height in the circumferential direction and / or in the axial direction. For the sake of completeness, it should be noted that it is of course also possible for at least some of the channels to be designed in such a way that the relevant channels are brought together at a distance from the conveying chamber / the rotor receiving chamber, so that a common conveying chamber end / a common conveying chamber opening is created.The latter form of design can in particular lead to a simplified design, smaller installation space requirements and / or improved functionality of the rotary vane pump in question.
[0021] Furthermore, it is proposed that the compensation channel in the rotary vane pump be arranged such that, in an operating state of the rotary vane pump, it opens into the lubricant chamber completely below the lubricant level of the lubricant chamber, and preferably, in a resting state of the rotary vane pump, it opens into the lubricant chamber at least partially, preferably at least substantially completely, above the lubricant level. Such a design can, in particular, enable a high degree of tightness of the compensation channel in an operating state of the rotary vane pump, combined with good ventilation effectiveness of the delivery chamber / rotor receiving chamber after the rotary vane pump is shut down.Furthermore, the amount of fluid flowing into the delivery chamber / rotor receiving space (in particular lubricant, but also external fluid and / or fluid to be pumped; also a mixture of different fluids, such as a mixture of lubricant and fluid to be pumped) can be kept as low as possible in order to maintain the effectiveness of the rotary vane pump and, if necessary, even increase it. If - as preferably proposed - in a rest state (in particular shortly after the rotary vane pump is switched off or shut down), the compensation end of the compensation channel opens into the lubricant chamber above the lubricant level, a particularly rapid ventilation of the delivery chamber / rotor receiving space can be achieved and / or the amount of lubricant flowing into the delivery chamber / rotor receiving space can be minimized. These are typically properties that are desired for rotary vane pumps.
[0022] Furthermore, it is proposed to design the rotary vane pump such 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, in particular the lubricant level in the operating state of the rotary vane pump. 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) filled with a gaseous fluid. This can effectively prevent unwanted contamination of the environment (external space) by lubricant. Furthermore, the lubricant loss from the rotary vane pump can be reduced, which is also advantageous.In this context, it should be noted that any lubricant entrained by the ventilation channel from the lubricant chamber into the delivery chamber / rotor receiving chamber (for example in the form of a lubricant mist) is generally unproblematic and, in particular, is generally negligible compared to the amount of lubricant introduced via the compensation channel (although the amount of lubricant introduced into the delivery chamber / rotor receiving chamber through the compensation channel is itself comparatively small thanks to the proposed design of the rotary vane pump).
[0023] Furthermore, it is proposed to design the rotary vane pump such that the discharge channel is arranged such that, in an operating state of the rotary vane pump, it opens into the lubricant chamber at least partially, preferably at least substantially completely, below the lubricant level in the lubricant chamber. This particularly applies to an operating state of the rotary vane pump; however, it can also apply to a resting state of the rotary vane pump. This generally makes it possible for the valve device to be particularly tight, so that the effectiveness of the rotary vane pump can be increased and / or that valve devices of comparatively simple construction and / or cost-effective manufacture can be used.
[0024] It is further proposed that in the rotary vane pump, 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 preferably separated from one another by a partition, more preferably by an overflow partition. Thanks to this comparatively simple development, it is particularly possible that when the rotary vane pump is switched off, the lubricant level in the lubricant bath can drop particularly quickly, and thus, in particular, the compensation end of the compensation channel can particularly quickly come to lie partially / largely completely above the lubricant level (by lowering the lubricant level). This can, in particular, significantly reduce the lubricant entry via the compensation channel into the delivery chamber / the rotor receiving space.By providing a lubricant storage area separated from the lubricant bath, the lubricant storage volume (which can be pumped, for example, to the relevant areas of the rotary vane pump via feed pumps and the like to lubricate the various components) can be selected to be particularly large, allowing the rotary vane pump to operate for extended periods without the need for lubricant refills. This can, in particular, extend maintenance intervals and / or reduce the likelihood of damage due to lubricant loss.Another advantageous property of the partition wall is usually that it largely precisely defines the lubricant level in the lubricant bath, especially when the rotary vane pump is operating (excess lubricant drains over the partition wall into the lubricant reservoir; it should be noted that lubricant is usually replenished via the discharge channel). This allows the lubricant level relative to the equalizing end of the equalizing channel, the venting end of the venting channel, and / or the discharge end of the discharge channel (primarily the equalizing end of the equalizing channel) to be defined particularly easily and precisely, both in the operating state and in the idle state of the rotary vane pump.For the sake of completeness, it should be noted that the lubricant level in the lubricant bath is generally higher than the lubricant level in the lubricant storage area, particularly when the rotary vane pump is in operation, but often also when the rotary vane pump is switched off.
[0025] It is possible for the partition wall to have at least one drain opening and / or at least one recess in the area of the upper edge of the partition wall. The number and size of the recesses in the area of the upper edge of the partition wall and / or the drain openings should be selected such that the amount of lubricant draining through these recesses / drain openings is compensated for by additionally pumped lubricant under all realistically expected operating conditions when the rotary vane pump is in operation. As a rule, a safety margin must be taken into account. The drain openings can in particular be designed as through holes in the partition wall. The proposed design can in particular promote a particularly rapid drop in the lubricant level in the area of the lubricant bath when the rotary vane pump changes from an operating state to a rest state.This in turn can reduce the entry of lubricant into the rotor receiving chamber / the delivery chamber when the rotary vane pump is switched off.
[0026] It is further proposed that at least one volume-reducing device, in particular a bead device, be provided in the lubricant chamber, in particular in the lubricant bath, particularly preferably in an upper fill level region of the lubricant chamber and / or the lubricant bath. This makes it possible, for example, to reduce the cross-section of the lubricant bath in its upper fill level region (especially in the region of the upper edge of the partition wall). An upper fill level region can be understood in particular as the area 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 makes it possible to further accelerate the drop in the lubricant level when the rotary vane pump transitions from an operating state to a rest state.Accordingly, the lubricant ingress into the rotor receiving space / feed chamber can be further reduced. The beading device can be arranged on the partition wall, particularly in the area of the upper edge of the partition wall. Additionally or alternatively, it is also possible for the partition wall to be curved, resulting in a cross-section of the lubricant bath that tapers towards the top.
[0027] Furthermore, it is proposed to design the rotary vane pump such that the valve device is designed, at least in part, as a valve reed device. In particular, a valve device or a valve reed device can also be provided with multiple valve reed regions. This allows a comparatively simple and cost-effective design of the valve device to be realized. In particular, in conjunction with at least partial immersion of the valve device in the lubricant chamber / lubricant bath, a particularly high sealing effect of the valve device can generally be achieved.
[0028] When designing the rotary vane pump, it is possible – and often preferred – to provide a plurality of intake channels, discharge channels and / or valve devices and / or valve reed devices and / or ventilation channels and / or compensation channels and / or delivery chambers and / or rotors and / or rotor receiving chambers. This can generally significantly increase the functionality of the rotary vane pump. In particular, it is possible to improve the pumping performance, the achievable pressures, the noise development and / or the ventilation after the rotary vane pump has been switched off / shut down. However, it should be noted that the rotary vane pump can also have exactly one rotor receiving chamber, one rotor, one delivery chamber, one intake channel, one discharge channel, one valve device, one compensation channel and / or one ventilation channel.However, it is equally conceivable that one, a plurality, or all of the aforementioned elements may each occur multiple times (in particular twice, three times, four times, five times, or six times). In this context, particular attention is also drawn to the possibility of "mixed combinations," i.e., for example, such that a rotary vane pump with a rotor and a rotor receiving chamber may have, for example, three delivery chambers, two intake channels, four discharge channels, a valve device (in particular a valve device with multiple valve regions, such as, in particular, valve reed regions), a ventilation channel, and two compensation channels. Other combinations are, of course, also conceivable.
[0029] It is further proposed that at least one ventilation channel and / or at least one compensating channel in the rotary vane pump have at least one fluid flow-limiting device, in particular at least one throttle device. This can further increase the functionality of the respective channel. If the fluid flow-limiting device is also designed to be variable and / or replaceable (in each case, in particular with regard to the achievable fluid flow rate), it is also possible to adapt the rotary vane pump particularly easily for different areas of application / applications. For example, by using a different throttle device, the rotary vane pump can be adapted for use with a different lubricant (e.g., different viscosity) without requiring excessively complex adaptation work.
[0030] Another conceivable design of the rotary vane pump results when at least one valve device in the rotary vane pump is designed as a completely sealing valve device, in particular such that at least one valve tongue region of the valve device is designed essentially without recesses. This generally allows the effectiveness of the rotary vane pump to be further increased. In particular, pumping losses and / or reduced pressure quality / vacuum quality can generally be avoided. It should be noted that functionalities such as ventilation during operation to reduce noise and / or ventilation of the rotor receiving chamber / the delivery chambers of the rotary vane pump when the rotary vane pump is switched off can be implemented by devices specifically designed and constructed for this purpose (equalization channel / ventilation channel), which can be optimized for the respective functionality to be achieved.In a certain sense, the proposed design can therefore also be understood to mean that the valve device is or can be optimized for its intended use, namely in such a way that it allows fluid to flow through in (essentially) only one direction.
[0031] A further embodiment of the rotary vane pump results when the dimensioning of the rotary vane pump, in particular the volume of the lubricant chamber, particularly preferably the volume of the lubricant bath, is selected such that a lowering of the lubricant level during the transition from the operating state to the idle state of the rotary vane pump is realized by an initial lubricant transfer from the lubricant chamber and / or the lubricant bath via the compensation channel into the delivery chamber / rotor receiving chamber, wherein the maximum lubricant transfer (in particular with regard to the volume) into the delivery chamber is dimensioned such that a re-commissioning of the rotary vane pump is not significantly adversely affected, in particular substantially not adversely affected, by the lubricant located in the delivery chamber.Additionally or alternatively, the maximum lubricant transfer (particularly in terms of volume) into the pumping chamber should be dimensioned such that the release of lubricant in the area of the intake channel or into the intake channel is reduced, in particular minimized, or at least substantially prevented. This allows the desired functionality for rotary vane pumps when switching off / shutting down the rotary vane pump (moving the rotary vane pump from an operating state to a standby state) to be achieved using comparatively simple and cost-effective means.The volume of transferred lubricant should, in particular, be so small that, when the rotary vane pump is restarted, no undesirably high drive torque is required and / or no increased wear occurs and / or no damage to the mechanical components (in particular wall elements / vanes or the like) occurs (at least under realistically expected operating conditions). In particular, it is proposed that the rotary vane pump be designed and configured such that the relative arrangement of the lubricant level in the lubricant chamber and / or in the lubricant bath, on the one hand, and the discharge channel and / or the compensation end of the compensation channel, on the other hand, results (exclusively) from a (height / level) variation of the lubricant level.Such a variation in the lubricant level can be achieved, in particular, by appropriately dimensioning the lubricant chamber / lubricant bath. This makes the desired functionality particularly easy to implement technically. In particular, no moving mechanical components are required for this purpose.
[0032] In particular, it is proposed that in the rotary vane pump, the at least one delivery chamber is at least partially delimited by wall elements that are displaceable and / or pivotable relative to the rotor. In particular, the displaceability of wall elements (often referred to as vanes) relative to the rotor can be achieved by displaceably mounting the wall elements in correspondingly designed receiving slots (often referred to as vane slots) in the rotor. It is pointed out that mechanical wear caused by relative movement between the rotor and the wall element(s) can be reduced with the aid of the lubricant. This design typically results in 2, 3, 4, 5, 6, 7, 8, 9, 10 or more delivery chambers (in particular per rotor receiving area), whereby the above is not necessarily limited to this design.
[0033] Furthermore, it is proposed that the ventilation channel of the rotary vane pump, in particular the fluid flow limiting device of the ventilation channel, be dimensioned such that, in an operating state of the rotary vane pump, a noise reduction is achieved without significantly impairing the delivery capacity of the rotary vane pump. This, too, generally represents a particularly desirable operating behavior of the rotary vane pump. Thanks to the proposed design of the presently proposed rotary vane pump, this particularly desirable operating behavior of the rotary vane pump can be technically realized using comparatively simple means.
[0034] Furthermore, it is proposed that the compensating channel, in particular the fluid flow limiting device of the compensating channel, be dimensioned such that sufficient ventilation of the pumping chamber is achieved when the rotary vane pump is shut down without significantly impairing the operating state due to lubricant and / or fluid flowing back through the compensating channel. This, too, is a particularly desirable operating behavior for rotary vane pumps. Thanks to the design of the rotary vane pump proposed here, this desired operating behavior of the rotary vane pump can be easily achieved using comparatively simple means.
[0035] Further advantages, features, and objects of the invention will become apparent from the following detailed description of the invention in combination with the accompanying drawings. The drawings show:
[0036] Fig. 1 is a schematic cross-sectional view of a rotary vane pump with a laterally arranged lubricant chamber;
[0037] Fig. 2 is an enlarged detail of Fig. 1 in the area of the exhaust duct, ventilation duct and compensation duct;
[0038] Fig. 3: a side plan view of the area with the valve tongue device of the rotary vane pump shown in Fig. 1;
[0039] Figure 4: A side view of an overflow partition in the lubricant chamber of the rotary vane pump shown in Fig. 1. Fig. 1 shows a schematic cross-sectional view of a rotary vane pump 1. Such rotary vane pumps 1 are known in the art in terms of their basic design and are used for a wide variety of applications.
[0040] The rotary vane pump 1 has a housing 2 in which a hollow space – the rotor receiving space 3 – is formed. Arranged eccentrically in the rotor receiving space 3 is a rotor 4 which can be set in a rotational movement along a rotational axis 5. In the illustrated embodiment, the rotor 4 has three vane slots 6, in each of which a wall element 7 (often also referred to as a vane, vane, or vane blade) is arranged so as to be displaceable relative to the rotor 4 such that the wall elements 7 rotate together with the rotor 4. The rotation of the rotor 4 about the rotational axis 5 presses the wall elements 7 against an inner wall 8 of the rotor receiving space 3 due to centrifugal force. 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 space 3 is reduced, thus significantly reducing wear on the rotary vane pump 1.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 space 3 has a sealing function so that no fluid to be pumped can flow past here.
[0041] The wall elements 7 divide the rotor receiving chamber 3 (which remains taking into account the rotor 4) into three delivery chambers 11, namely delivery chambers 11 a, 11 b, and 11 c. Due to the current position of the rotor 4 and the dead center 15, the delivery chamber 11 c can also be considered divided into two sub-delivery chambers 11 c, 11 c' separated from each other by the dead center. Due to the eccentric arrangement of the rotor 4 in the rotor receiving chamber 3, the volume of the delivery chambers 11 varies cyclically during the course of a rotation of the rotor 4 of the rotary vane pump 1, so that a fluid can be delivered.
[0042] The fluid to be pumped is sucked into one of the - in this case three - pumping chambers 11 via an intake opening 12 (currently pumping chamber 11a and possibly also pumping chamber 11c'). The pumping chamber 11 in question is - as already mentioned - delimited by two adjacent wall elements 7. Due to the initial expansion of the pumping chamber 11 in question, fluid to be pumped is sucked into the pumping chamber 11 in question (pump chamber 11a). After the pumping chamber 11 in question 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 (pump chamber 11b). From a certain angular position of the rotor 4 orof the respective delivery chamber 11, a fluidic connection to the discharge channel 13 is created and the fluid to be delivered is expelled from the delivery chamber 11 via the discharge channel 13 into the lubricant chamber 14 (delivery chamber 11c). The fluid is expelled into the lubricant chamber 14 via the valve reed device 21, which opens when the pressure in the delivery chamber 11 is slightly higher than the pressure in the lubricant chamber 14 (typically approximately atmospheric pressure). The described cycle then begins again. Of note here is 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.
[0043] The lubricant chamber 14 is connected via a flange region 16 to the region of the housing 2 of the rotary vane pump 1 in which the rotor receiving chamber 3 with the rotor 4 is formed. In the present exemplary embodiment, the lubricant chamber 14 has two different regions. These are the lubricant bath 17 arranged adjacent to the discharge channel 13 and the lubricant storage region 18, which is designed separately from it. The lubricant bath 17 and the lubricant storage region 18 are separated from each other by a partition wall, which in this case is designed as an overflow partition wall 19.
[0044] The discharge end 20 pointing toward the lubricant bath 17 is connected to the lubricant bath 17 via a valve device, which in this case is designed as a valve reed device 21. The valve reed device 21 is connected, for example, to the housing 2 of the rotary vane pump 1 by means of screws 22. In the exemplary embodiment shown here, the valve reed device 21 has four elastic valve reed regions 23 (see also the view according to Fig. 3), which cover the respective discharge ends 20 of the four discharge channels 4, which in this case are also arranged next to one another in the axial direction of the rotational axis 5 of the rotor 4. Thanks to the elastic valve reed regions 23, the fluid to be pumped by the rotary vane pump 1 can flow only from the rotor receiving space 3 toward the lubricant chamber 14 - but not in the opposite direction.
[0045] In the present case, the rotary vane pump 1 is designed such that the discharge ends 20 of the discharge channels 13 open into the lubricant bath 17 below the lubricant level 24 in the operating state of the rotary vane pump 1. This has the advantage that the lubricant 10 located in the lubricant bath 17 exerts a certain fluid pressure on the elastic valve reed regions 23, and thus the discharge ends 20 of the discharge channels 13 are securely (fluid-tight) closed by the valve reed regions 23. Of course, the ambient pressure in the lubricant chamber 14 exerts pressure on the lubricant 10 in the lubricant bath 17. Furthermore, the lubricant 10 provides a certain sealing of any gaps and cracks that may be present, so that the tightness of the valve reed device 21 is also particularly high.
[0046] As can be seen in particular from the enlarged view in Fig. 2, in the presently illustrated embodiment of a rotary vane pump 1, in addition to the discharge channels 13, a ventilation channel 26, which in this case is formed completely separately from the discharge channel 13, as well as (in this case) two compensation channels 29, which are also formed completely separately from the discharge channel 13 and the ventilation channel 26, are provided.
[0047] The ventilation channel 26 has a ventilation end 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 discharge 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 region of the rotor receiving chamber 3. This leads to a reduction in noise generation, especially at rotational speeds of the rotor 4 that are in a marginal range.Since the ventilation opening 26 can be designed in an optimized manner for the purpose of noise reduction, a partially significant noise reduction can be achieved with comparatively little construction effort, without other advantageous properties of the rotary vane pump 1 (some of which are explained in more detail below) being adversely affected to a significant extent.
[0048] In particular, it is possible for the ventilation channel 26 to be provided with a suitably dimensioned throttle 32. Furthermore, it is also possible to make the throttle 32 replaceable, allowing the rotary vane pump 1 to be quickly adapted to different operating environments and for different purposes (even retroactively).
[0049] Furthermore, in the presently illustrated embodiment, two compensating channels 29 are provided, which are arranged at the same height but axially offset from one another (relative to the rotational axis 5 of the rotor 4) (see also the view in Fig. 3). Of course, a different number of compensating channels 29 is also possible (which also applies to the ventilation channels 26).
[0050] The compensating ends 30 of the compensating channels 29 are arranged such that they lie just below the lubricant level 24 of the lubricant bath 17 during the operating state of the rotary vane pump 1. As a result, the lubricant 10 in the lubricant bath 17 creates a certain sealing effect, so that only a minimal (net) fluid throughput (if any) occurs through the outlet channels 29 during operation of the rotary vane pump 1. This applies both to the flow of fluid to be pumped from the rotor receiving space 3 toward the lubricant chamber 14, as well as to the flow of fluid (in particular lubricant 10) from the lubricant chamber 14 or from the lubricant bath 17 toward the rotor receiving space 3.What is particularly noteworthy about the arrangement of the compensating ends 30 of the outlet channels 29 is that, although they are completely below the lubricant level 24 in the operating state of the rotary vane pump 1, they are only just below the lubricant level 24 in the operating state of the rotary vane pump 1. This is relevant because after the rotary vane pump 1 is switched off (regardless of whether intentionally or unintentionally), the compensating 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 in the switched-off state of the rotary vane pump 1 (indicated by a dashed line in Figs. 1 to 3). This will be discussed in more detail below.
[0051] In an operating state of the rotary vane pump 1, the rotation of the rotor 4 causes a fluid to be pumped, enriched with the lubricant 10 (the fluid to be pumped is sucked in via the suction opening 12), to be pumped from the pumping chamber 11 adjacent to the discharge channel 13 (in this case, pumping chamber 11c) into the discharge channel 13 by means of the cyclically expanding and contracting pumping chambers 11. Due to the resulting pressure, the elastic valve tongue regions 23 of the valve tongue device 31 are pushed away from the wall of the flange region 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) maintains the lubricant level 24 in an upper range during the operating state of the rotary vane pump 1.The upper lubricant level 24 is essentially defined by the upper edge 35 of the overflow partition 19. The function of the optionally provided recesses 36 in the region of the upper edge 35 of the overflow partition 19, or of the likewise optionally provided drain openings 37 in the overflow partition 19, will be discussed below. In any case, the number and size of the recesses 36 and drain openings 37 - if present - must be dimensioned such that, under all realistically expected operating conditions of the rotary vane pump 1, the lubricant level 24 remains in the region of the upper edge 35 of the overflow partition 19 during the operating condition of the rotary vane pump 1, whereby an increase in the lubricant level 24 above the upper edge 35 of the overflow partition 19 is prevented by overflow 38 of the lubricant 10 (in Fig.1 and 2 by an arrow 38), whereby the lubricant 10 flows from the lubricant bath 17 into the lubricant storage area 18 of the lubricant chamber 14 due to the overflow 38.
[0052] Lubrication of the rotary vane pump 1, particularly in the area of the rotor 4 or the rotor receiving chamber 3, can be achieved by lubricant pumps (not shown here), which, for example, release lubricant 10 in the area of the intake opening 12 of the rotary vane pump. Such lubricant pumps and such lubrication of the rotary vane pump 1 are known in the prior art.
[0053] When the rotary vane pump 1 is stopped (for example due to an intentional shutdown, but also due to an unintentional failure), air or fluid (in particular predominantly gaseous fluid) is sucked from the lubricant chamber 14 into the rotor receiving chamber 3 via the ventilation channel 26. 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 stoppage of the rotary vane pump 1, no "replenishment" of lubricant 10 takes place 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 reduced lubricant level 34 when the lubricant pump 1 is switched off. Accordingly, the compensation ends 30 of the compensation channels 29 are now exposed, so that air orEssentially gaseous fluid is sucked from the lubricant chamber 14 into the rotor receiving space 3. This allows for particularly rapid pressure equalization of the rotor receiving space 3. Since the rotor receiving space 3 can thus be brought to ambient pressure (typically atmospheric pressure) particularly quickly, it can be ensured that only small amounts of lubricant enter the rotor receiving space 3. This advantageously prevents the rotor receiving space 3 from filling up with lubricant.
[0054] 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 19 and / or by drain openings 37 in the overflow partition 19. The number and size of the recesses 36 and / or drain openings 37 can be selected such 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).In order 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 (in particular in the case of the drain openings 37) or by the possibility of an attachable drain edge (in particular in the case of recesses 36 in the region of the upper edge 35).
[0055] Furthermore, in the illustrated embodiment, a likewise optional bead 39 is provided in the area of the upper edge 35 of the overflow partition 19. This bead 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 off state 34 of the rotary vane pump 1 (compared to the situation without the bead 39). The bead 39 also increases the effectiveness of the recesses 36 and / or the drain openings 37 (if present).
[0056] Furthermore, it is possible that only individual elements (or even a certain subset of the described features) of the embodiment of the rotary vane pump 1 described here in detail are picked out and combined with the generic description of the rotary vane pump proposed here.
Claims
Patent claims 1. Rotary vane pump (1) for conveying a fluid to be conveyed, comprising a housing (2) with a rotor receiving space (3) and a lubricant chamber (14), a rotor (4) arranged eccentrically in the rotor receiving space (3) in such a way that at least one conveying space (11) is formed, the volume of which varies cyclically during rotation of the rotor (4), an intake channel (12) for supplying the fluid to be conveyed into the at least one conveying space (11) and an exhaust channel (13) for expelling the fluid to be conveyed from the at least one conveying space (11) in the direction of the lubricant chamber (14), wherein a valve device (21) is provided between the exhaust channel (13) and the lubricant chamber (14) in order to prevent a backflow of fluid, in particular lubricant and / or fluid to be conveyed, from the lubricant chamber (14) into the at least one conveying space (11), wherein the Rotary vane pump (1) is designed and arranged in such a waythat the discharge channel (13) is arranged such that it opens into the lubricant chamber (14), characterized by: at least one ventilation channel (26), which is fluidically connected by a delivery chamber end (28) to the at least one delivery chamber (11) and by a ventilation end (27) to a space outside the at least one delivery chamber (11), and by at least one compensation channel (29), which is fluidically connected by a delivery chamber end (31) to the at least one delivery chamber (11) and by a compensation end (30) to the lubricant chamber (14), wherein the rotary vane pump (1) is designed and configured such that the compensation end (30) opens into the lubricant chamber (14) when the rotary vane pump (1) is in an operating state below the lubricant level (24), and when the rotary vane pump (1) is in a rest state above the lubricant level (34) Lubricant chamber (14) opens., 2. Rotary vane pump (1) according to claim 1, characterized in that the delivery chamber end (28) of the ventilation channel (26) and / or the delivery chamber end (30) of the compensation channel (29) opens directly into the delivery chamber (11) of the rotary vane pump (1).
3. Rotary vane pump (1) according to claim 1 or 2, characterized in that the compensation channel (29) is arranged such 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), opens into the lubricant chamber (14) at least partially, preferably at least substantially completely, above the lubricant level (34).
4. Rotary vane pump (1) according to one of the preceding claims, characterized in that the ventilation end (27) of the ventilation channel (26) opens into the lubricant chamber (14).
5. Rotary vane pump (1) according to one of the preceding claims, characterized in that the discharge channel (13) is arranged such that, in an operating state of the rotary vane pump (1), it opens into the lubricant chamber (14) at least partially, preferably at least substantially completely, below the lubricant level (24) of the lubricant chamber (14).
6. Rotary vane pump (1) according to one of the preceding claims, characterized in that the lubricant chamber (14) has a lubricant bath (17) adjacent to the discharge channel (13), as well as a lubricant storage area (18), wherein the lubricant bath (17) and the lubricant storage area (18) are preferably separated from one another by means of a partition wall, preferably by means of an overflow partition wall (19).
7. Rotary vane pump (1) according to claim 6, characterized in that the partition wall (19) has at least one drain opening (37) and / or at least one recess (36) in the region of the upper edge (35) of the partition wall (19).
8. Rotary vane pump (1) according to one of the preceding claims, in particular according to claim 6 or 7, characterized in that in the lubricant chamber (14), in particular in the lubricant bath (17), particularly preferably in an upper filling level area of the lubricant chamber (14) and / or the lubricant bath (17), at least one volume reduction device, in particular a bead device (39) is provided.
9. Rotary vane pump (1) according to one of the preceding claims, characterized in that the valve device (21) is designed at least in regions as a valve tongue device (23).
10. Rotary vane pump (1) according to one of the preceding claims, 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 delivery chambers (11) and / or rotors (4) and / or rotor receiving chambers (3).
11. Rotary vane pump (1) according to one of the preceding claims, characterized in that at least one ventilation channel (26) and / or at least one compensation channel (26) has at least one fluid flow limiting device, in particular at least one throttle device (32, 33).
12. Rotary vane pump (1) according to one of the preceding claims, in particular according to one of claims 9 to 11, characterized in that at least one valve device (21) is designed as a completely sealing valve device, in particular such that at least one valve tongue device (23) is designed substantially free of recesses.
13. Rotary vane pump (1) according to one of the preceding claims, in particular according to one of claims 6 to 12, characterized in that the dimensioning of the rotary vane pump (1), in particular the volume of the lubricant chamber (14), particularly preferably the volume men of the lubricant bath (17), is selected such that a lowering of the lubricant level (24) during the transition from the operating state to the idle state of the rotary vane pump (1 ) is realized by an initial lubricant transfer from the lubricant chamber (14) and / or the lubricant bath (17) via the compensation channel (29) into the delivery chamber (11 ), wherein the maximum lubricant transfer into the delivery chamber (11 ) is dimensioned such that a re-commissioning of the rotary vane pump (1 ) is not impaired by the lubricant located in the delivery chamber (11 ).
14. Rotary vane pump (1) according to one of the preceding claims, in particular according to one of claims 6 to 13, characterized in that the rotary vane pump (1) is designed and arranged such that the relative arrangement of lubricant level (24, 34) in the lubricant chamber (14) and / or in the lubricant bath (17) on the one hand and discharge channel (13) and / or compensation end (30) of the compensation channel (29) on the other hand results from a variation of the lubricant level (24, 34).
15. Rotary vane pump (1) according to one of the preceding claims, characterized in that the at least one conveying chamber (11) is at least partially delimited by wall elements (7) which are displaceable and / or pivotable relative to the rotor (4).
16. Rotary vane pump (1) according to one of the preceding claims, in particular according to one of claims 11 to 15, characterized in that the ventilation channel (26), in particular the fluid flow limiting device (32) of the ventilation channel (26), is dimensioned such that in an operating state of the rotary vane pump (1) a noise reduction is realized without significantly impairing the delivery capacity of the rotary vane pump (1).
17. Rotary vane pump (1) according to one of the preceding claims, in particular according to one of claims 11 to 16, characterized in that the compensating channel (29), in particular the fluid flow limiting device (33) of the compensating channel (29), is dimensioned such that sufficient ventilation of the delivery chamber (11) is ensured at a Shutdown of the rotary vane pump (1) is achieved without significant impairment of the operating state by lubricant and / or fluid to be pumped flowing back through the compensation channel (29).