GB2312249A

GB2312249A - Rotary pivoted-vane pump

Info

Publication number: GB2312249A
Application number: GB9708026A
Authority: GB
Inventors: Manfred Sommer
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-04-20
Filing date: 1997-04-21
Publication date: 1997-10-22
Anticipated expiration: 2017-04-21
Also published as: FR2747744A1; GB9708026D0; ITTO970334A1; JPH1030579A; DE19716439A1; GB2312249B; IT1292264B1; ITTO970334A0; FR2747744B1

Abstract

Vanes 70 are pivotable about respective radial axes (75, Fig 3.1) so as to be transverse to the direction of motion 34 in a supply-duct part 54 from an inlet 31 to an outlet 32 of an annular duct 30 and to be parallel to the direction of motion 34 in a sealing-duct part 55 from the outlet 32 to the inlet 31 of the annular duct. The sealing-duct part 55 has a cross-section corresponding to the vanes when parallel to the direction of rotation 34 and is always sealed by at least one vane passing through it. At least one deflecting element 90.1 for pivoting the vanes is provided at the transition from the supply-duct part 54 to the sealing-duct part 55. In the region which makes contact with the deflecting element 90.1, the thrust face of the vane 70 has a surface contour 71 adapted to the shape of the control edge or face of the deflecting element.

Description

Rotary swing-vane pump The invention relates to a rotary swing-vane pump, and particularly to a pump with a drive and an annular duct which comprises a suction connexion and a pressure connexion and the supply-duct part of which has a constant cross-section, and with swing vanes which can be set in rotation about the axis of rotation in the duct and which are formed with flat vanes and which are connected to the drive and are pivotable about their pivot axes in a plane situated in the direction of rotation and which in the supplyduct part are arranged with their thrust faces approximately transversely to the direction of rotation, and with a sealing-duct part which is formed in the duct between the suction connexion and the pressure connexion and which has a cross-section corresponding to the shape of the swing vanes pivoted in the direction of rotation and which is always sealed by at least one swing vane, and with at least one deflecting element provided at the transition from the supply-duct part to the sealing-duct part and comprising a control edge or face for pivoting the vanes.

With respect to the mounting of the swing vanes, two main designs of rotary swing-vane pumps of this type are known. In one the swing vanes are pivotable about pivot axes arranged radially or at right angles to the axis of rotation. The disc-shaped vanes are arranged transversely to the direction of rotation in the supply-duct part and parallel to the direction of rotation in the sealing-duct part. Because of disoshaped design, the cross-sectional area of the vanes in a plane embracing the axis of rotation in the supply-duct part is larger than in the sealing-duct part. In particular, the vanes are frequently made with flat circular discs, but can also be produced with flat rectangular plates. Pumps of this type are described for example in DE-OS/PS 21 60 162, DE-OS 23 54 375, DE-OS 25 53 192 and DE-OS/PS 30 46 155.

In the other design the pivot axes of the swing vanes are not radial or at right angles to the axis of rotation, but are parallel to the axis of rotation. In many designs arranged in accordance with this principle, the swing vanes in the sealing-duct part are pivoted into recesses in the hub, so that their cross-sectional area in a plane embracing the axis of rotation in the sealing-duct part becomes zero. Axial swing-vane pumps of such designs are described for example in DE-OS 2845 658.

In order to pivot the swing vanes, two main designs of the pivoting mechanism are also known. In the case of one design the bearing journals of the swing vanes are driven in such a way that the vanes in the supply-duct part and in the sealing-duct part each occupy the pre-determined position. Rotary swing-vane pumps with a pivoting mechanism of this type are known for example from DE-OS 25 53 192, DE-OS 28 45 658, AT-PS 9304 and DE-PS 230 929.

In the case of the other design of the pivoting mechanism the supply duct or a part thereof is frequently formed in such a way that it is constricted on one side of the pivot axis, so that the vanes have to avoid this constriction by pivoting. The swing vanes are moved back either by means of springs, as described for example in US-A-2,135,161, or by coupling with a swing vane which is opposite with respect to the axis of rotation and which during the run-up to the constriction by its pivoting jointly pivots the opposite swing vane connected to it. Designs of this type are described for example in DE-OS/PS 21 60 162, DE-OS 23 54 375 and DE-OS/PS 30 46 155.

In particular, in the case of rotary swing-vane pumps of the last type in which the swing vanes are pivoted by contact of the vanes with constrictions at the transition from the supply-duct part to the sealing-duct part, it is not possible to avoid wear during prolonged operation, particularly on the thrust faces of the vanes. In this way, defects can arise during the pivoting of the vanes, until total failure of the pump occurs.

In a number of rotary swing-vane pumps, such as for example US-A-2,135,161, US-A-713,663 or DE-OSIPS 21 60 162, the constrictions forcing the pivoting of the vanes are produced in the form of relatively long run-up ramps with flat pitch angles.

This results in a relatively large area of the pump duct, or a relatively large rotationalangle range for pivoting the swing vanes. This limits the conveying capacity of these pumps to a corresponding degree. It thus appears advantageous to restrict the constriction to a relatively small area of the pump duct, i.e. to use as far as possible those deflecting elements which allow the pivoting of the swing vanes to be restricted to small rotational angles. In order to achieve high conveying capacities it is additionally necessary to arrange the swing vanes in such a way that they reliably seal off the sealing-duct part. In this case, however, undesired jamming of the vanes in the region of the constriction can occur, until destruction of the vanes takes place together with complete failure of the pump. Since only relatively rigid vanes of steel or plastics materials having suitable properties are possible for reliable operation, in order to mitigate this problem the constriction was formed hitherto with a flexible deflecting element, preferably of rubber, which allowed relatively large resilient deformation.

Such an arrangement is known from DE-OS/PS 30 46 155. This pump has hitherto proved advantageous in particular in pumping highly abrasive substances and/or corrosive media, such as for example liquids containing fruit acid or vinegar. In this pump design the entire annular duct was lined completely with plastics material or rubber, in order to ensure that no corrosive substances could come into contact with metallic parts of the pump housing. However, with this design a relatively large amount of energy is absorbed in the region of the constriction during the pivoting of the swing vanes. The operation of this pump therefore requires a relatively large amount of driving energy.

It would therefore be desirable to be able to provide an improved arrangement of the rotary swing-vane pump which can permit reliable operation over a prolonged period with high conveying capacities and an energy-saving manner of operation.

The present invention provides a rotary swing-vane pump in which, in the pivoting contact area touching the control edge or face of the deflecting element, the thrust faces of the vanes are provided - in a cross-section formed at a right angle to the pivot axis with a surface contour which deviates from a straight line and which is adapted to the shape of the control edge or face of the deflecting element.

This results on the one hand in advantageous sliding and moment conditions, so that the vanes are reliably prevented from jamming in the region of the deflecting element which forms the constriction. On the other hand, because of this step, it is possible to restrict the pivoting of the vanes to a small area of the pump chamber or to small rotational angles, so that maximum conveying capacities are thereby possible. In addition, it is possible to dispense with the use of energy-absorbing materials in the pivoting contact area, as a result of which the pump can be operated with reduced driving energy.

The thrust faces of the vanes may advantageously be made concave, at least in partial areas. In this way, with advantageous sliding and moment conditions during the pivoting of the vanes, optimum sealing of the sealing-duct part is also possible in conjunction with optimum conveying capacity.

In a further advantageous arrangement, in the pivoting contact area the surface contour of the thrust faces may be formed - in a cross-section at a right angle to the pivot axis - with a continuous curve, preferably made ellipsoidal or circular. This implies uniform pivoting of the vanes with favourable moment and load-application conditions.

In a fUrther particularly advantageous arrangement an insertion element is provided, which is associated with the deflecting element and comprises control edges or faces and which is opposite the deflecting element with respect to the plane of rotation described by the pivot axes of the swing vanes during the rotation of the said swing vanes and is arranged offset with respect to the said deflecting element in the direction of rotation. This also allows reliable pivoting of the vanes even after prolonged operation of the pump.

The deflecting element and the insertion element may advantageously be adapted to each other in such a way that the pivot angle corresponding to the pivoting of the vanes on the deflecting element is very much greater than the insertion pivoting angle corresponding to the pivoting of the vanes on the insertion element, in which case the pivoting angle may advantageously be greater than or equal to 60". This makes possible relatively rapid pivoting of the vanes while at the same time taking into consideration the acceleration forces which occur, in which case reliable pivoting of the vanes into the sealing-duct part is ensured despite the wear which is unavoidable during prolonged operation.

The thrust faces of the vanes and the control edges or faces of the insertion and/or deflecting element may advantageously be adapted to one another in such a way that the rotational angle corresponding to pivoting of the vanes through approximately 90 amounts to less than 40". Large conveying capacities are possible as a result of these steps at the same time as prolonged reliable operation.

In an advantageous arrangement the deflecting element is formed with a round rod or tube bent through 90". As a result, the deflecting element occupies the smallest possible space in the pump duct, without obstructing the conveying flow. This is advantageous particularly when conveying sensitive fluid media that contain lumpy constituents, which are thus not subject to any undesired compression or shearing even in this area.

In this case the deflecting element may advantageously be arranged in such a way that the surface contour of its control edge or face is made circular in a cross-section at a right angle to the pivot axis. This arrangement ensures sufficiently rapid pivoting of the vanes in a small space.

The thrust faces of the vanes in the pivoting contact area preferably have a radius which is greater than the radius of the control edge or face of the deflecting element.

The thrust faces of the vanes may advantageously extend evenly and parallel to one another outside the pivoting contact area and have an approximately rectangular shape in a plane embracing the axis of rotation. This permits very good sealing of the sealingduct part, in which case on the one hand complete sealing is made possible shortly after the entry of the vane into the sealing-duct part and on the other hand the sealing-duct part is sealed until the vane has virtually completely left the said sealing-duct part. In this way, the sealing-duct part can be made relatively short, i.e. occupying only a relatively small rotational-angle area. This has the advantage of a supply-duct part more extended over a larger rotational-angle area in conjunction with greater conveying capacities which can be achieved. This is advantageously assisted by making the radial outer surfaces of the vanes parallel to the pivot axis.

Further details, arrangements, advantages, and preferred features of the invention may be seen in the following description with reference to the accompanying drawings, in which: Fig. 1 is a plan view of an opened rotary swing-vane pump comprising two housing parts; Fig. 2 is a cross-section through the closed rotary swing-vane pump along the sec tion line 2-2 in Fig. 1; Fig. 3.1 is a plan view of one of the swing vanes; Fig. 3.2 is a lateral view of the swing vane according to Fig. 3.1; Fig. 3.3 is a view from below of the swing vane according to Fig. 3.2; Fig. 4 is an enlarged partial cut-away view in the region of the deflecting element with a section through the swing vane along the line 4-4 in Fig. 3.2 in a position after complete pivoting on the deflecting element with a partial sectional illustration of the sealing-duct part; Fig. 5 is a reduced plan view of a connecting pin connecting two respective swing vanes in a rotationally fixed and releasable manner.

The pump 20 comprises a pump housing 21 which is divided into the two housing parts 22 and 23 along the separation plane 28. The said two housing parts 22 and 23 are joined together in a sealed manner by means of a seal 24, for which purpose use is made of the clamping bolts 25 which extend through the bores 26 in the lugs 27. The pump housing 21 has an annular duct 30 which is formed by the supply-duct part 54 and the sealing-duct part 55. The two connexions 31 and 32, which are provided with the connexion flanges 33 for the connexion of supply or discharge lines, open tangentially into the duct 30. Although the pump is set up for right-hand and left-hand operation or forwards and backwards operation, for the sake of simplicity the connexion 31 will be referred to as an inlet or a suction connexion and the connexion 32 will be referred to as an outlet or a pressure connexion. They perform this function when the pump is running clockwise in accordance with the arrow 34 in Fig. 1.

The swing vanes 35 rotate in the annular duct 30. Four swing vanes 35 are provided, which are each arranged at an angle of90" to each other. In this embodiment the swing vanes 35 are each formed in one piece with the vane 70, the bearing journal 37 and a stop collar 50 provided at the transition between the bearing journal 37 and the vane 70. As an alternatively to this, the swing vanes 35 can each be formed with two separate swing-vane parts, in which case one swing-vane part is formed with the bearing journal 37 and the other swing-vane part is formed with the vane 70 as well as the stop collar 50 integrally moulded thereon. The two swing-vane parts are advantageously releasably connected to two guide pins insertible with exact fitting in mutually parallel bores extending parallel to the pivot axis 75. Instead of the guide pins with suitably shaped bores, it is also possible however to use flat sections insertible in suitably shaped openings in an exactly fitting but releasable manner. When the swing vanes 35 are formed with two swing-vane parts in the manner described, the vanes 70 can be interchanged in a simple manner, without the bearing journals 37 having to be removed and replaced.

The swing vanes 35 are arranged so as to be pivotable about their pivot axes 75 which are situated in the rotational plane referred to as the separation plane 28 and covered during the rotation of the swing vanes 35 about the axis of rotation 29 and which extend radially to the axis of rotation 29 of the pump 30. The bearing journals 37 are mounted in the bearing bores 39 provided in the hub member 40. The hub member 40 is integrally moulded in the manner of a flange on a driving sleeve 41 and frees a control cavity 42. The bearing journal has a diameter 78 which is chosen to be as large as possible in order to achieve favourable pivoting-moment conditions. The hub member 40 is sealed in a sliding manner and is supported on the circular cylindrical bearing shoulder 44.1 and 44.2 respectively of the housing parts 22 and 23 by way of the circular cylindrical sliding sealing rings 43.1 and 43.2. The shaft seal 45 is provided for the further sealing of the driving sleeve 41. The drive shaft (not shown) is connected in a rotationally fixed manner to the sleeve 41 and the hub member 40 - with the aid of a feather key which engages in the groove 46 - in a manner not shown in detail.

The swing vanes 35 are supported in the inside with their stop collar 50 on the circular cylindrical bearing shoulder 51. The inwardly projecting bearing journals 37 of opposed swing vanes 35 are, as shown in Figs. 1, 2 and 5, connected together in a rotationally fixed but releasable manner with the aid of connecting rods 47, 48 which are straight here, in which case the vanes 70 of the swing vanes 35 opposed in pairs are arranged offset from one another at approximately 900 about their pivot axis 75. The connecting rods 47, 48 which can also be made tubular have an external diameter 106 at least in the region of their two ends. As shown in Fig. 2 and Figs. 3.1 to 3.3, they engage in an exactly fitting manner in the bore 73 with the diameter 107 provided in the bearing journal 37. As shown in Fig. 3.3 in particular, the bore 73 is offset by the angle 74 with respect to the median plane 80 of the vane 70 and is arranged eccentrically with respect to the pivot axis 75 thereof by the distance 104. This makes it possible for the two pairs of vanes to be pivotable independently of one another. The connecting rods 47, 48 each have two rotation-preventing pins 87.1, 87.2 which are formed at a distance from each other and in the same plane and at right angles to the connecting-rod axis 89 and which are arranged at the same distance in each case from the centre of the rod. In the assembled state the rotation-preventing pins 87.1 and 87.2 engage in the respective rotation-preventing groove 76 arranged on the inwardly directed end of the bearing journal 37. In order to secure the axial position the connecting rods 47, 48 each have the two stop collars 88.1 and 88.2 which are each arranged directly adjoining the rotation-preventing pins 87.1 and 87.2 and between them. The stop collars 88.1, 88.2 are flattened in a circular manner on the side of the connecting rods 47 and 48 respectively opposite the rotation-preventing pins 87.1 and 87.2, so that the connecting rods 47, 48 can be arranged eccentrically to the pivot axis 75 at the maximum possible distance without obstructing the pivoting movement, and in order to permit the most advantageous possible lever conditions when pivoting the swing vanes 35 connected to one another. Instead of the rotation-preventing pins 87.1, 87.2 and the narrow stop collars 88.1, 88.2 other auxiliary elements can also be provided for fixing the position and preventing rotation. For example, instead of the stop collars, it is possible to provide wider stop support pins capable of bearing a load and arranged at right angles to the connecting-rod axis 89. In order to prevent rotation, the said stop support pins are provided at their end remote from the connecting rod 47 with rotation-preventing rods which extend parallel to the connecting-rod axis 89 and which have approximately the same external diameter as the extemal diameter 106 of the connecting rods 47. The said rotation-preventing rods engage fitting in associated bores in the bearing journal 37 of the swing vanes 35 which are provided eccentrically with respect to the pivot axis 75 and in this respect opposite the bore 73. This design makes it possible to transmit relatively large swing-vane forces and moments, which can be advantageous in particular in the case of relatively large pumps.

If more than two pairs of swing vanes or four swing vanes 35 are used, for example three pairs of swing vanes or six swing vanes 35, at least two of the three connecting rods are advantageously made alternately bent over on different sides, while the third connecting rod can be made straight. In this way, in this embodiment with more than two pairs of swing vanes, it is also made possible for all three pairs of swing vanes to pivot independently of one another, In order to clean the pump 30 and/or to replace the swing vanes 35, after loosening the three clamping bolts 25 and lifting off the housing part 23 it is possible to lift off the entire hub member with the swing vanes 35 mounted therein in a simple manner, without any bolts having to be loosened. In order to dismantle the swing vanes 35 or the vanes 70 they can be simply withdrawn towards the outside. In order to clean the pump and/or to replace worn vanes, it is thus merely necessary to loosen the three clamping bolts 25. All the other parts can be lifted off or withdrawn in a simple manner, without any bolts or other fastening elements having to be loosened, as a result of which an easy and rapid dismantling or assembly of the entire pump or of pump parts worn after prolonged use is possible.

In its supply-duct part 54 the annular duct 30 has a cross-section corresponding to the shape of the vanes 70 arranged transversely to the direction of rotation. In the sealing-duct part which extends over a shorter rotational-angle area between the inlet 31 and the outlet 32 the duct 30 has a cross-section which corresponds to the shape of the vanes 70 pivoted in the direction of rotation, i.e. it is reduced in this area to the thickness 92 of the vanes 70. For this purpose, sealing members 56 and 57, which are fastened to the housing parts 22 and 23 respectively with the aid of bolts (not shown) or in another manner, are inserted in the duct 30 extended in an annular manner over the entire periphery.

The deflecting element 90.1 is arranged at the transition from the supply-duct part 54 to the sealing-duct part 55 in order to pivot the swing vanes 35. It is formed with a circular cylindrical rod which is bent at approximately 90" and of which one end 93 is rigidly connected to the initial end face 53 of the sealing member 57 and the other end 94 is rigidly connected to the housing part 21. The deflecting element is connected to the duct wall by welding, but in order to replace the deflecting element in a simple manner it can also be connected with the aid of connecting means (not shown). In the region of the curvature of the deflecting element 90.1 directed towards the separation plane 28, the said deflecting element 90.1 has a radius of curvature 96 which is adapted with respect to a rapid pivoting of the swing vanes 35. The spatial arrangement of the deflecting element 90.1 relative to the swing vanes 35 is chosen in such a way that its deflecting edge 98 touches the thrust face 71 for the first time in an area as close as possible to the bearing journal 37, so that the pivoting-contact area is situated in the vicinity of the mounting of the swing vanes 35. In this way, advantageous moment and force application conditions are produced for pivoting the swing vanes 35.

The upper edge 97 of the deflecting element 90.1 extends in a straight line and passes in alignment into the sealing face 60 of the sealing member 57. The said sealing member extends through the entire sealing-duct part 55, from the initial end face 53 situated in the region of the outlet 32 as far as the final end face 58 formed in the region of the inlet 31.

During prolonged operation of the pump it is not possible to avoid a certain degree of wear of the thrust faces 72 of the vanes 70, in particular in the region of their radial rims or edges 102 at the transition to their radial outer surfaces 82. This results in the risk that the vanes will not be pivoted completely in the direction of rotation 34 before entering the sealing-duct part 55, so that they can become skewed or jam on the initial end face 53.

In order to avoid this difficulty in insertion caused by wear or in order to permit longer trouble-free operation of the pump, an insertion guide element 91.1 formed with a wedge-shaped run-up ramp 101 is provided at the transition of the sealing face 60 to the final end face 58 of the sealing member 56. The said insertion element 91.1 is situated opposite the deflecting element 90.1 with respect to the rotational plane 28 described by the pivot axes 75 of the swing vanes 35 during the rotation thereof and it is arranged offset from the said deflecting element 90.1 in the direction of rotation 34 (Fig. 4).

The run-up ramp 101 forms an acute angle 103 with the sealing face 60 and in this embodiment it is formed by a portion of the sealing member 57 which is offset by the angle 59 with respect to the final end face 58 (Fig. 1). In order to facilitate the pivoting in, the vanes 70 can be made rounded or flattened at least in part on their radial rims or edges 102, so that the vanes 70 in this area have a cross-section which tapers inwardly towards their radial rims or edges 102.

The insertion element 91.1 is associated with the deflecting element 90.1 with respect to the pivoting of the vanes 70 during the operation of the pump 20 in the direction of rotation indicated by the arrow 34 in Fig. 1 (Fig. 4). In contrast, the insertion guide element 91.2 is associated with the deflecting element 90.2 with respect to the pivoting of the vanes 70 during the operation of the pump 20 contrary to the direction of rotation indicated by the arrow 34 in Fig. 1 (Fig. 2).

The sealing face 60 extends flat and parallel to the separation plane 28 as far as the region of the insertion element 91.2 and with the exception of the region directly adjacent to the hub member 40 at a distance corresponding to half the thickness 100 of the vanes 70.

A sealing member 56 which is similar but is made mirror-symmetrical is inserted in the sealing-duct part 55 of the housing part 23. In this case the insertion element 91.1 associated with the deflecting element 90.1 is situated in the region of the outlet 32. A similar deflecting element 90.2 is arranged mirror-symmetrically to the deflecting element 90.1 in the region of the inlet 31. One respective deflecting element 90.1, 90.2 is accordingly provided on each side of the sealing-duct part 55 associated with the transition from the supply-duct part 54 to the sealing-duct part 55, in which case one deflecting element 90.1 is arranged on one side and the other deflecting element 90.2 on the other side of the rotational plane 28 described by the pivot axes 75 of the swing vanes 35 during the rotation thereof. This mirror-symmetrical arrangement is chosen so that the pump can be driven both in the right-hand and the left-hand direction as well as both in forwards and backwards operation. The sealing constriction 61, the area profile of which corresponds to the shape of the vanes 70 pivoted in the peripheral direction, is formed between the two sealing faces 60 of the two sealing members 56 and 57.

The arrangement of the vanes 70 of the swing vanes 35 is described below in greater detail with reference to Figs. 3 and 4: The relatively flat vanes 70 are essentially shaped in the form of discs. The axial outer faces 81 directed towards the housing 30 are rounded in the manner of a partial sphere with the radius 77 in the same way as the outer face 52 of the housing 30 immediately opposite them, and the radial outer faces 82.1 and 82.2 of the vanes 70 are rounded in the manner of partial circular cylinders with the radius 83. In all possible positions of the swing vanes 35 these steps result in a trouble-free abutment and sealing inside the duct 30. In addition, at the transition from the stop collar 50 of the swing vanes 35 to the vane 70 the said swing vanes 35 have a transition radius 79 which corresponds to the conditions specific to the materials and the stress. Accordingly, the two sealing members 56 and 57 are rounded in a convex manner on their edges facing the vanes 70.

For the sake of simplicity and on account of the possibility of operating the pump in right-hand and left-hand operation, the thrust or suction faces of the swing vanes 35 are referred to below as thrust faces 72.1 and 72.2, so that each vane 70 has two thrust faces 72.1, 72.2. In the pivoting contact area of the thrust faces 72.1, 72.2 of the vanes, i.e. the area in which they touch the deflecting edge or face 98 of the deflecting element 90.1 during the pivoting, the vanes are formed with an ellipsoid or circular segmental groove 71 with a radius or main radius 84 which is greater than the radius 96 of the deflecting element 90.1. In addition, the thrust faces 72.1, 72.2 of the vanes 70 arranged symmetrically to their pivot axis are constructed in the form of flat faces parallel to one another.

Accordingly, as shown in Fig. 4, the vanes 70 have a dumb-bell-shaped crosssectional profile in a cross-section formed at a right angle to their pivot axis 75 in the region of the pivoting contact area. The groove 71 has the depth 85. This is selected to be such that on the one hand the vanes 70 are reliably prevented from jamming by the levers or moment condition and load-application or force conditions arising during the pivoting of the vane 70 on the deflecting member 90.1. On the other hand the groove depth 85 is adapted in accordance with the requirements and conditions specific to the materials. The width 86 of the concave groove 71 is selected to be sufficiently large in accordance with the diameter 95 of the deflecting element 90.1 or in accordance with the contact conditions actually occurring.

Since the pump 20 is intended in particular for foodstuffs, drinks and corrosive media in the chemical industry, all the parts coming into contact with the media are produced from sufficiently resistant materials, in which case when luxury articles have to be pumped their physiological harmlessness is particularly important. Possible materials for the pump housing 21 or the supply-duct part 54 are in particular stainless special steel, and also bronze, cast iron and

The mode of operation of the pump is described below: The individual movement phases are best seen in Fig. 1. The description starts at position 63. When the hub member 40 is turned in the direction of the arrow 34 by a motor (not shown) by way of a shaft (likewise not shown), it entrains all the swing vanes 35. Their vanes 70 are situated transversely or at right angles to the direction of rotation at positions 63 and 64.

The vane 70 at position 63 presses the conveying medium present between it and the vane at position 64 in accordance with the direction of rotation indicated by the arrow 34 in the direction towards the outlet 32 and itself reaches the position 64. During this the conveying medium is conveyed towards the outlet 32. This is assisted in particular by the fact that after entering the sealing-duct part 55 the vane 70 alternating from position 64 to position 65 closes the said sealing-duct part 55 in a sealing manner, so that the conveying medium conveyed from position 63 to position 64 by the change of positions is conveyed almost entirely to the outlet 32. In this embodiment, however, a small part of the conveying medium is entrained through the sealing-duct part 55 to the outlet 31 between two respective vanes 70 pivoted in the direction of rotation.

Shortly after reaching position 64 the vane 70 reaches the deflecting element 90.1 arranged in the region of the transition from the supply-duct part 54 to the sealing-duct part 55 and is entrained by the said deflecting element 90.1, so that it pivots about its pivot axis 75, until before reaching the point 65, in particular before entering the sealing-duct part 55, it occupies the position (Fig. 4) pivoted in the direction of rotation 34 and thus rests against the upper edge 97 of the deflecting element 90.1 extending parallel to and in alignment with the sealing face 60. In this way, the pivot angle forcibly set by contact with the deflecting element 90.1 during the rotation of the swing vanes 35 about the axis of rotation 29 is approximately 900 in the case of non-worn vanes 70.

If, however, the thrust faces 72 display certain signs of wear after prolonged operation of the pump 20, before entering the sealing-duct part the vane 70 no longer reaches the position pivoted in the direction of rotation 34, but a pivoting position slightly inclined with respect to the rotational plane 28. In this case the vane 70 strikes the runup ramp 101 of the insertion element 91.1 in the region of the edge 102 present at the transition of the thrust face 72.1 to the radial outer face 82.2 and there in the course of rotation it is pivoted in a sliding thrusting movement in the direction of rotation 34, until it completely seals off the sealing-duct part 55 formed between the two sealing members 56 and 57. With the exception of the areas formed with the insertion elements 91.1, 91.2 the said sealing-duct part 55 has the thickness 92 of the vane 70 over its entire length.

If the vane 70 entering the sealing-duct part 55 has entered the latter so far that it completely seals of the sealing-duct part 55 the leading vane 70 returns a short distance in the sealed-off sealing-duct part 55 and then leaves it. When it has gone out completely it is moved into a position pivoted at right angles or obliquely to the direction of rotation, namely as a result of the fact that the opposite vane 70 connected in a rotationally fixed manner to it runs up onto the deflecting element 90.1 and is pivoted. In the course of this pivoting movement the vane 70 draws the conveying medium through the inlet 31, while being assisted in particular by the fact that the trailing vane 70 is still sealing the sealing-duct part 55. After that, the conveying medium enclosed between two swing vanes arranged vertically or transversely to the direction of rotation is guided through the conveying duct 54 in a gentle manner, i.e. without substantial compression.

During the rotation through the conveying-duct part 54 the vane 70 is held in its position at right angles or transversely to the direction of rotation as a result of the fact that the opposite vane 70 connected thereto in a rotationally fixed manner rests on the upper edge 97 of the deflecting element 90.1 or is held in the sealing-duct part 55 between the two sealing faces 60 so as to be prevented from rotating or rests on the upper edge 97 of the deflecting element 90.2 arranged symmetrically to the deflecting element 90.1. In this way, an automatic control performed in the pump chamber is carried out in order to pivot the swing vanes 35.

Because of the mode of operation of the pump 20 in the manner of a reciprocating pump, it is self-priming. Since, on the other hand, it is constructed as a rotation pump, however, a highly uniform flow is discharged in the pressure line practically without pulsations.

The pivoting movement of the vanes 70 about their pivot axis 75 after running up onto the deflecting element 90.1 and 90.2 respectively and the application of load or force and lever-arm or moment conditions are described in detail below. In order to explain the advantageous arrangement of the vanes 70, they are compared below with a vane not constructed in an advantageous manner with thrust faces formed over the entire width in the form of flat faces. It is assumed that the swing vanes 35 rotate at a constant rotational speed, so that they cover the same distances or rotational angles during equal periods of time. The lever arms occurring at the corresponding positions should likewise be taken into consideration. These positions are situated in a plane formed at a right angle to the pivot axis and on the one hand are bounded by their point of intersection with the pivot axis 75 and on the other hand are bounded on the deflecting edge or face 98 of the deflecting elements 90.1 and 90.2 respectively by the contact point currently changing in its position as a function of the individual positions.

During the pivoting of the vane 70 the length of the lever arm changes continuously, namely starting from a maximum length in a position in which the vane 70 is still situated at a right angle or transversely to the direction of rotation, as far as a minimum length in a position in which the vane 70 is pivoted completely in the direction of rotation, ie. is turned through approximately 90". This means first of all that starting from the initial position the moment conditions deteriorate to an increasing extent as a result of the lever arm becoming continuously shorter. On the other hand, during the entire pivoting time required for the complete pivoting through approximately 90 an effect of force is produced which is directed towards the deflecting edge or face 98 and which in turn induces an effect of force contrary to the direction of rotation 34. In this way, in particular when using rigid and wear-resistant vanes 70, an undesired jamming of the said vanes 70 can occur in the region of the deflecting element 90.1. This results in damage to differing degrees on the thrust faces 71 of the vanes 70 and on the deflecting element 90.1, which can lead to complete failure of the pump 20 in conjunction with a complete destruction of the operating parts involved. This problem cannot be reliably solved even by increasing the radius 96 of the deflecting element 90.1 or by an evenly ascending deflecting element or a deflecting element shaped in some other way.

In contrast, in the case of the advantageous arrangement of the thrust faces 72.1, 72.2 of the vanes 70 favourable lever-ann or moment conditions occur in the pivoting contact area during the entire pivoting period. The lever arms which occur are always greater than the lever arm which occurs with an unfavourable thrust-face arrangement with the vane pivoted completely in the direction of rotation 34. In addition, it has been found that favourable load-application and force conditions exactly the reverse of the conditions with an unfavourable thrust-face arrangement are present during the really critical pivoting period. It follows from this that, starting from the position in which the lever arm is at a right angle to the direction of rotation 34, the thrust face 72 of the vane 70 just slides on the deflecting edge or face 98 of the main deflecting member 90.1.

This reliably prevents the vane 70 from jamming in this region in an undesired manner.

Although load-application or force ratios directed towards the deflecting member 90.1 likewise occur in the brief pivoting period until the position last described is reached, this has been found to be insignificant owing to the very great lever-arm length here in conjunction with the thickness 92 of the vanes 70 and the angles currently set in the pivoting contact area relative to the deflecting element 90.1.

In the present case, therefore, it is particularly important, by a suitable arrangement of the thrust faces 72.1, 72.2 of the vanes 70 in the pivoting contact area, to produce favourable conditions with respect to the forces arising there and directions of force and with respect to the lever-arm and moment conditions arising there, in which case a combination effect of the influencing variables illustrated has also to be taken into consideration.

To sum up, the rotary swing-vane pump (20) has a drive and an annular duct (30) which comprises a suction connexion and a pressure connexion (31, 32) and the supplyduct part (54) of which has a constant cross-section. The pump (20) comprises swing vanes (35) which are formed with flat vanes (70) and which are connected to the drive and which can be set in rotation about the axis of rotation (29) in the duct (30). The swing vanes (35) are pivotable about their pivot axes (75) in a plane situated in the direction of rotation (34) and in the supply-duct part (54) they are arranged with their thrust faces (72) approximately transversely to the direction of rotation (34). The pump (20) has a sealing-duct part (55) which is formed in the duct (30) between the suction connexion (31) and the pressure connexion (32) and which has a cross-section corresponding to the shape of the swing vanes (35) pivoted in the direction of rotation (34) and which is always sealed by at least one swing vane (35) passing through it. At least one deflecting element (90) comprising a control edge or face for pivoting the vanes (70) is provided at the transition from the supply-duct part (54) to the sealingduct part (55). In the pivoting contact area touching the control edge or face of the deflecting element (90), the thrust faces (72) of the vanes (70) have a surface contour which permits favourable pivoting conditions and which is adapted to the shape of the control edge or face of the deflecting element (90).

List of references: 20 pump 21 pump housing 22 housing part 23 24 seal 25 clamping bolt 26 bore 27 lug 28 separation plane / plane of rotation 29 axis of rotation 30 duct 31 connexion / inlet / suction connexion 32 connexion I outlet I pressure connexion 33 connexion flange 34 arrow I direction of rotation 35 swing vane 37 bearing journal 39 bearing bore 40 hub member 41 driving sleeve 42 control cavity 43.1 sliding sealing ring 43.2 44.1 bearing shoulder 44.2 45 shaft seal 46 groove 47 connecting rod 48 50 stop collar 51 bearing shoulder 52 outer surface 53 initial end face 54 supply-duct part 55 sealing-duct part 56 sealing member 57 91 insertion guide member 91.1 insertion guide member 91.2 92 thickness of 70 93 end 58 final end face 59 angle 60 sealing face 61 sealing constriction 63 vane position 64 65 vane position 66 70 vane / outer surface 71 groove 72 thrust face 72.1 thrust face 72.2 73 bore 74 angle 75 pivot axis 76 rotation-preventing groove 77 sphere radius 78 diameter of 37 79 transition radius 80 median plane 81 axial outer surface 82 radial outer surface 82.1 radial outer surface 82.2 " 83 radius 84 radius 85 groove depth 86 width 87.1 rotation-preventing pin 87.2 88.1 stop collar 88.2 89 connecting-rod axis 90 deflecting element 90.1 deflecting element 90.2 94 95 diameter of 90 96 radius of curvature 97 upper edge 98 deflecting edge/ face 100 half thickness of 70 101 run-up ramp 102 edge 103 angle 104 distance 106 external diameter 107 diameter

Claims

CLAIMS: 1. A rotary swing-vane pump comprising drive means, an annular duct which has a suction connexion and a pressure connexion and a supply-duct part of substantially constant cross-section, swing vanes which can be set in rotation in the duct about a pump axis and which comprise flat vanes, the swing vanes being connected to the drive means and being pivotable about respective pivot axes in a plane situated in the direction of rotation, the swing vanes in the supply-duct part having their thrust faces approximately transverse to the direction of rotation, the duct including a sealing-duct part between the suction connexion and the pressure connexion, the sealing-duct part having a cross-section which corresponds to the shape of the swing vanes pivoted in the direction of rotation and being always sealed by at least one passing swing vane , and at least one deflector at the transition from the supply-duct part to the sealing-duct part, the deflector having a control edge or face for pivoting the vanes, characterized in that, in the region which makes contact with the control edge or face of the deflector, the thrust face of each vane - in a cross-section at a right angle to the pivot axis - has a surface contour which deviates from a straight line and which is adapted to the shape of the control edge or face of the deflector.
2. A pump as claimed in claim 1, in which the thrust faces of the vanes are made concave, at least partially.
3. A pump as claimed in claim 1 or 2, in which in the contact region the surface con tour of the thrust face - in a cross-section at a right angle to the pivot axis - is formed with a continuous curve.
4. A pump as claimed in claim 3, in which in the contact region the surface contour of the thrust face is ellipsoidal or circular in a cross-section at a right angle to the pivot axis.
5. A pump as claimed in any preceding claim, in which a guide which comprises a control edge or face is associated with the deflector, the guide being arranged opposite the deflector with respect to the plane of rotation described by the pivot axes of the swing vanes during the rotation of the swing vanes and being arranged offset with respect to the deflector in the direction of rotation.
6. A pump as claimed in claim 5, in which the deflector and the guide are adapted to each other in such a way that the angle corresponding to the pivoting of the vanes on the deflector is much greater than the angle corresponding to the pivoting of the vanes on the guide.
7. A pump as claimed in claim 5 or 6, in which the pivot angle is greater than or equal to 60".
8. A pump as claimed in any of laims 5 to 7, in which the thrust faces of the vanes and the control edge or face of the guide and/or deflector are adapted to one another in such a way that the rotational angle corresponding to pivoting of the swing vanes through approximately 90" amounts to less than 40".
9. A pump as claimed in any preceding claim, in which the deflector comprises a round rod or tube bent through 900.
10. A pump as claimed in any preceding claim, in which the surface contour of the control edge or face of the deflector is circular in a cross-section at a right angle to the pivot axis.
11. A pump as claimed in any preceding claim, in which the thrust faces of the vanes, in the contact region, have a radius which is greater than the radius of the control edge or face of the deflector.
12. A pump as claimed in any preceding claim, in which the thrust faces of the vanes extend straight and parallel to one another outside the contact region.
13. A pump as claimed in any preceding claim, in which the thrust faces of the vanes have a substantially rectangular shape in a plane containing the axis of rotation.
14. A pump as claimed in any preceding claim, in which the radial outer surfaces of the vanes are substantially parallel to the pivot axis.
15. A pump substantially as described with reference to, and as shown in, the accompanying drawings.