EP3055567B1 - Rotary piston pump made of plastic - Google Patents

Description

The present invention relates to a rotary pump or metering pump made of plastic with two via gears coupled to each other, rotatably driven rotors, which are mounted in a pump housing, which is provided with intake and outlet, each rotor having a rotor shaft whose rotor shaft ends in the walls store the pump housing.

Metering pumps are known in all sizes and types. As metering pumps made of plastic hand-operated piston pumps are known in particular, as they are known on soap dispensers for liquid soaps or as here of particular interest in the hospitality industry, where, for example, in fast food companies mustard, ketchup or creamer delivered with such hand-operated piston pumps metered. Despite these metering pumps, however, the quantity delivered varies relatively greatly, since in the case of the metering pumps, in particular those as described here, the stroke should actually be fully utilized with each actuation, but this is usually not the case. Instead, often one, two or three Kurzhube be carried out and varies accordingly, the amount very strong. As long as this amount is given as an addition to a hamburger, this plays only a minor role. But where such dosing pumps are also used to add a special amount of a liquid food to a recipe, the taste is varied by incorrect operation, which is not always appreciated by customers.

Although various other types of pumps are well known, especially rotor pumps, but these are usually relatively high precision, made of metal This is also required in the food industry, where large quantities must be dispensed in a dosed manner. For commercial use, however, usually very inexpensive disposable metering pumps are usually delivered free of charge. Accordingly, such metering pumps must be made of plastic, have the simplest possible structure and work reliably.

The plastic metering pump of interest here should be designed in particular for foods that are dispensed in so-called tubular bags or other soft packaging made of plastic films.

Many liquid foods also contain larger amounts of solids. Typical examples of such liquid foods are, for example, sauce tartare, mustard sauces with pickles, vanilla sauce with chocolate or almonds, etc. With the dosing pumps customary today, such solid liquid foods can not be dispensed in metered quantities. In particular, with so-called gear pumps as such, for example in the FR-2313971 is shown, this can hardly be realized. For larger solid particles, such as almond pins, they are ground by the rotors or block the rotors. Correspondingly, dosing pumps are suitable for such dosing pumps, in particular in which the rotors have two or more rolling elements. Examples of such pumps are from the US 3054417 where a metering pump for liquid media is shown for adding other liquids, in which case each rotor has three wing arms and these wing arms roll each other and transport the medium on. In such pumps between the housing and the individual rotor blades enough space to transport liquids with solid particles. Here are less the larger solid particles a problem, but rather the smaller solid parts that stick to the mutually rolling rotor blades and are completely crushed during the rolling process, whereupon a coating can form, which reduces the flow rate and can even lead to blockages.

The same applies to a metering pump according to the WO 95/24556 , in which only two-bladed rotors are shown, but also roll against each other as well as on the housing wall each other.
Another rotary lobe pump is out of the EP-1 892 417 known. However, this is designed as an insert for an outer metallic housing, but is created for one-way use and has a plastic housing. The gear transmission with which the correct relative position of the two rotors is ensured, is part of a arranged outside of the actual pump gear and not part of the intended for disposable parts. The intermeshing rotors have part-cylindrical rotor blade shoes and concave indentations, but the latter are not shaped in such a way that the rotary piston pump is particularly suitable for products with solids content. In particular, the comparatively narrow radii of the concave recesses allow it to occur in these areas deposits that remain in the pump and possibly spoil quickly in the case of food by contact with the outside air. Sealing components in the form of lip seals for the rotor shafts are present as separate elements to be inserted. Because of the design of this rotary lobe pump as an insert in a rigid metal housing and because of the rotors penetrating drive shafts which also serve the purpose of keeping the housing parts sealing together, here focus the sealing measures as well as specifically on this area. From the US 5180299 is a rotary vane pump for powerful vehicle engines known. To better seal against air leakage, a thin elongated strip of sealing material is placed in a notch on the wing. It is therefore the object of the present invention to provide an improved metering pump, which has a relatively high flow rate and is particularly suitable for conveying solid-liquid mixtures, without having the disadvantages described above. In particular, should as possible largely the air access to the ingredients contained in the tubular bag are reduced so that they do not spoil prematurely.

This object is achieved by the feature combination of claim 1.

The solution essentially comprises that in a generic rotary piston pump with two identical rotors, a number of seals are integrally or integrally formed on the respective rotor.

The number of gaskets integrally formed on the respective rotor preferably includes at least lateral sealing lips on the rotor blade walls, sealing scraping edges on the outer surfaces of the rotor blade shoes, and longitudinal scraping ribs on the rotor shafts.

The integral arrangement of the seals on the respective rotor has the advantage that the rotary lobe pumps for single use of plastic can be produced very cost-effectively and from very few individual parts.

In a particularly preferred embodiment, each rotor blade shoe has on the outside of the part-cylindrical wall at least one sealing scraping edge running parallel to the rotor axis. Such a sealing scraping edge can be arranged close to the front edge in the direction of rotation of the respective part-cylindrical wall of the rotor blade shoe. However, it can, as shown in the embodiment described below, also be arranged centrally. Sealing edges ensure that no deposits can build up on the housing wall.

Further advantageous embodiments of the subject invention will become apparent from the dependent claims and their meaning and effect are described in the following description with reference to the accompanying drawings.

Fig. 1

Eine bevorzugte Verwendung der erfindungsgemässen Dosierpumpe angebracht auf einem Schlauchbeutel.

Fig. 2

zeigt eine perspektivische Ansicht der Dosierpumpe mit dem Befestigungsstutzen, wobei die lösbare Pumpengehäusewand entfernt worden ist.

Fig. 3

zeigt nochmals die Dosierpumpe in einer Seitenansicht, wiederum unter Weglassung der lösbaren Pumpengehäusewand, während

Fig. 4

die beiden Rotoren für sich allein in korrekter Relativlage zueinander in perspektivischer Ansicht dargestellt sind.

Fig. 5

stellt eine perspektivische Teilansicht des Pumpengehäuses für sich allein und

Fig. 6

die lösbare Pumpengehäusewand in perspektivischer Ansicht mit Blick auf dessen Innenseite dar.

In the drawing, a preferred embodiment of the subject invention is shown. It shows:

Fig. 1

A preferred use of the metering pump according to the invention mounted on a tubular bag.

Fig. 2

shows a perspective view of the metering pump with the attachment piece, wherein the detachable pump housing wall has been removed.

Fig. 3

again shows the metering pump in a side view, again omitting the detachable pump housing wall, while

Fig. 4

the two rotors are shown by themselves in correct relative position to each other in a perspective view.

Fig. 5

represents a partial perspective view of the pump housing on its own and

Fig. 6

the detachable pump housing wall in perspective view with a view of the inside.

In the Fig. 1 is symbolically a preferred application of the inventive metering pump, which is generally designated 1, shown on a tubular bag 2. The metering pump 1 is held on the tubular bag 2 by means of a fastening sleeve 3 which is provided with a flange 4 on the tubular bag 2. The connection of the flange 4 with the tubular bag 2 is preferably carried out by ultrasonic welding.

The metering pump itself has a pump housing 5 with an intake manifold 6 and an outlet 7. The intake manifold 6 is screw-connected to the Attachment 3. The metering pump itself is shown here with a view to a fixed end wall 8 of the pump housing 5, in which case a rotor shaft end 15 provided with a drive coupling part 16 protrudes through said fixed end wall 8 and recognizes the drive coupling part 16. The drive coupling part serves to be positively connected to a drive means, not shown here.

In the Fig. 2 the metering pump 1 is shown with the attachment piece on its own. In this perspective view, one looks obliquely from above on the said flange 4 and detects opening means 17, which are formed here as perforating and incisors and in this position are still completely within the intake manifold 6 before the first use. Prior to initial use, you will screw the pump housing 5 with its intake 6 in the attachment piece 3 to a stop, said opening means 17 an aseptically closed container, preferably a tubular bag made of plastic film, cut open. In the transport position of the metering pump 1 shown here also the outlet port 7 is provided with a closure cap 18, which ensures that during transport and storage no foreign matter or foreign particles can get into the metering pump.

In the Fig. 2 the pump housing 5 is shown open. While in the Fig. 1 As already mentioned, looking at the fixed end wall 8 of the pump housing 5, here the metering pump 1 is shown rotated by 180 ° and you look at that side of the metering pump 1 with a detachable end wall 9. This detachable end wall 9 is shown laterally offset or released. The detachable end wall 9 can also be referred to as a pump housing cover. One looks in this figure on the outside of the pump housing cover and recognizes outwardly projecting closed bearing bushings 19, which are able to accommodate the rotor shaft ends 15 on the inside. The outwardly closed bearing bushes 19 are held stabilized with stiffening ribs 20 on the outside of the detachable end wall 9.

In the Fig. 3 the metering pump 1 is shown in the side position, but in the same situation as in Fig. 2 However, with the omission of the detachable end wall of the pump housing 5. In this view can be seen clearly, the two mounted in the pump housing 5 rotors 10, on which preferably integrally gears 11 are formed, which cause the two rotors when one of the two rotors driven will, move in opposite directions. With regard to the exact configuration of the two rotors 10 is on the following Fig. 4 directed. In the Fig. 3 it can be seen that each rotor is provided with a rotor shaft 12, wherein one looks here on the rotor shaft ends 15, and wherein on the rotor shafts 12 each two diametrically opposed rotor blade walls 13 are formed. At the peripheral ends of the rotor blade walls 13, a rotor blade shoe 14 is formed in each case. Each rotor blade has a part-cylindrical shape, which is adapted to the cylindrical part of the pump housing 5 in the curvature. As can be seen here, each rotor blade 14 constantly abuts either on the inside of the pump housing or on the rotor shaft 12 of the adjacent rotor.

In the Fig. 4 now the design of the two rotors can be seen in detail. These are shown on their own in a correct relative position as provided in the installation, but omitting the pump housing 5. The already in connection with the Fig. 3 mentioned parts, namely the rotor shaft 12 and the corresponding rotor shaft ends 15 are not referred to again here, so as not to unnecessarily burden the figure. The special embodiment of the rotor wing shoes 14 is particularly clearly visible in this figure. As already mentioned, the rotor blade shoes 14 are integrally formed on the peripheral ends of the rotor blade walls 13 in such a manner that the rotor blade walls 13 expand continuously substantially outwards and thus merge into the rotor blade shoes 14. The rotor blade shoes have a part-cylindrical outer surface 21. The radius of curvature of this outer surface corresponds to the distance between an axis which passes through the rotor shaft 12 extending centrally in the longitudinal direction and the outer surface 21 of Rotor Wing shoes. The outwardly widening rotor wing walls 13 form concave recesses 38, wherein the shape or the curve of the concave recesses is chosen and optimized so that in a pumping as little or no product residues remain in the concave recesses.

The inventive metering pump is preferably designed so that the pump seals the connection between the intake manifold 6 and outlet 7. For this purpose, the pump or its rotors 10 and the pump housing 5 on a plurality of different sealing elements. At the same time, however, these sealing elements also purify and prevent deposits in the pump housing, which can lead to a reduction in quality and leaks and, in the worst case, blockages of the pump.

Correspondingly, the rotor blade shoes 14 have at least one sealing scraping edge 23 on the outer surface 21. This can, as in the Fig. 4 be shown centrally, or it may for example be arranged near a leading edge in the direction of rotation 22. This sealing edge 23 has substantially the shape of a bead which runs parallel to the rotor shaft 12 on the aforementioned outer surface 21. As the name says, the Dichtschabkante 23 serves on the one hand, between the inner cylindrical wall of the pump housing 5 and the rotor 10 to form a seal, but at the same time this Dichtschabkante 23 should avoid by its scraping effect, the formation of deposits. Each rotor blade shoe 14 may also be provided with two sealing scraping edges 23, both near the leading end edge 22 and near the trailing end edge 22. Preferably, both rotors 10 are made absolutely identical so as to require only one injection mold. This also has the advantage that with the same design of the two rotors also during assembly no source of error arises.

The Dichtschabkante 23 preferably has a cross-sectionally approximately triangular shape, but other shapes are also possible.

In the Fig. 4 one recognizes, furthermore, that the rotor blade walls 13 have end faces 26. On the end faces 26, which come to lie in the installed state of the rotors in the pump housing 5 to the detachable end wall 25 and the pump housing cover, are centrally extending from the rotor shaft ends 15 to the outer surface 21 of the rotor blade 14 extending a respective sealing lip 27. On the opposite end, which is not visible here, the gears 11 are connected to these end faces in one piece. Here you will attach such sealing lips on the corresponding end face portions extending only from the corresponding gear to the outer surface 21 of the rotor blade shoes.

So that the rotor blade shoes 14 are sealed relative to the rotor shaft 12, 12 Längsabstreifrippen 28 are also mounted on the rotor shaft. These Längsabstreifrippen 28 extend parallel to the axis of the rotor shaft. In principle, it is sufficient to attach a Längsabstreifrippe 28 on each rotor shaft, but preferably two such Längsabstreifrippen are each mounted on the same page., These Längsabstreifrippen 28 not only act sealing, but also clean the Rotorflügelschuhe 14, on the outside of 21 of possibly itself there forming deposits. These constructive features practically a self-cleaning metering pump is formed.

In the Fig. 5 the pump housing 5 is shown by itself. The intake manifold 6 and the outlet 7 are only partially visible. Also in this solution, in turn, the pump housing cover, or the detachable end wall 9 of the pump housing is removed. Here, second bearing sleeves 29, 30 are formed, wherein the second bearing sleeve 29 is designed to be closed, and the other second bearing sleeve 30 is continuously open to the outside. In this open bearing sleeve 30, a circumferential sealing lip 31 is preferably formed with a lesser height. However, it is also possible for a plurality of such peripheral sealing lips 31 to be present, thus forming a kind of labyrinth seal practically. Alternatively, solutions are possible in which one or more circumferential sealing lips are not attached to the bearing sleeve 30, but at the rotor shaft end 15 used in this bearing sleeve, ie at the rotor shaft end with the drive coupling part sixteenth

The rotors 10 thus have on their rotor shafts 12 on both sides rotor shaft ends 15, which are designed as rotor shaft pin 35. The rotor shaft pin 35 on the side of the pump housing cover 9 have a smaller diameter, while the rotor shaft ends on the other side have a much larger diameter. Since, however, as already mentioned, preferably the two rotors are designed identically, both rotors also have a so-called drive coupling part 16 at that rotor shaft end with the larger diameter, which already has a reference to FIG Fig. 1 has been described. While in the Fig. 1 On the left the open bearing sleeve 30 is arranged and thus one recognizes there the drive coupling part 16 is in the Fig. 1 right, the closed bearing sleeve 29 shown. In the Fig. 5 , in which one now sees the pump housing from the inside, consequently, the closed, second bearing sleeve 29 is left and the second, open bearing sleeve 30 right recognizable. Only in the second, open bearing sleeve 30 will attach the corresponding circumferential sealing lip 31.

In the Fig. 6 is now the detachable end wall 9 and the pump housing cover 9 shown by itself. It can be seen on the peripheral edge of a plurality of spring tongues 32, which hook on the outside of the pump housing 5 in the closed state of the pump housing cover on the latching means 33 with corresponding cam 34.

As already mentioned 9 bearings are molded in the detachable end wall. However, these are referred to here as closed bearing bushes 19. Since these bushings 19 are closed, no additional sealing means are required here. The diameter of these closed bearing bushes 19 is substantially smaller than the diameter of the two bearing sleeves 29 and 30. In these closed bearing bushes 19 engage the rotor shaft ends 15, the as mentioned, are also designed as rotor shaft 35, as most clearly in the Fig. 4 is apparent.
The rotary piston pump described here has due to the integral arrangement of the seals on the rotors particularly good sealing properties. However, a further contribution to the good sealing properties also results from the special shape of the rotors, or the curve of the concave recesses on the rotors, which are so pronounced or optimized to the effect that in a pumping as little as possible or no product residues in the concave recesses remain.

For the purpose of reducing the residue, the rotor wing walls (13) with the rotor wing shoes (14) have the aforementioned concave indentations (38) at their peripheral ends, whose shape or curve is so pronounced or optimized that a quasi -permanent mutual contact of the end edges (22) with the surface of the concave recesses (38) takes place and consequently remain as little or no product residues in the concave recesses in a pumping operation. Any product residues in the concave recesses are continuously removed by the end edges (22) of the rotor blade shoes. The term 'quasi-permanent' is used here in a meaning that is intended to clarify that the described state, although not permanently, but recurring recurring recurrent.

• a) einerseits wegen des Merkmals, dass die Aussenfläche (21) jedes Rotorflügelschuhs (14) eines Rotors im Betrieb an der Rotorwelle (12) des benachbarten Rotors (10) anliegt. So kommt eine erste Teilkammer-Abdichtung zustande
• b) andererseits wegen der Eigenschaft, dass im Betrieb auch eine quasi-permanente gegenseitige Berührung der Endkanten (22) mit den Oberfläche der konkaven Einformungen (38) erfolgt. so kommt wenigstens annähernd eine zweite Teilkammer-Abdichtung zustande

In connection with the features described above for reducing the residue in the concave recesses, it can also be stated that partial chambers are formed in the intermediate region between the two rotors during operation in a quasi-permanent manner. These sub-chambers, which regularly recur in the pump operation but do not permanently exist, arise for the following reasons:

• a) on the one hand because of the feature that the outer surface (21) of each rotor blade shoe (14) of a rotor in operation on the rotor shaft (12) of the adjacent rotor (10) is present. This is how a first partial chamber seal is made
• b) on the other hand because of the property that during operation also a quasi-permanent mutual contact of the end edges (22) with the surface of the concave recesses (38) takes place. so at least approximately a second partial chamber seal comes about

Of course, the partitioning effect of these subchambers also at least partially achieves that the effects of the air ride on the ingredient in the tubular bag are reduced.

With the metering pump 1 described here, fluids and also mixtures of fluids and solids can be conveyed without problems. In this case, the size of the solid particles plays virtually no role, they must of course be in size so that it is less than the distance between the two rotor shafts. But whether the solid particles are coarse-grained or fine-grained and thus more or less prone to deposits does not matter. On the one hand, the solid parts are not ground, and on the other hand, their deposits on the pump housing and on the rotor wing shoes or on the rotor shafts are continuously removed by the means described above. This ensures that the metering pump, which serves as a disposable metering pump, always works reliably for the required service life. Since thanks to the construction described above also a high tightness between the outlet 7 and the tube bag 2 is maintained during the entire emptying a practically aseptic state in the tubular bag is obtained. Accordingly, the food which is delivered in the fully closed aseptic tubular bag can be offered without or at least substantially less preservative.

LIST OF REFERENCE NUMBERS

1. 1 dosing pump
2. 2 tubular bags
3. 3 fixing sockets
4. 4 flange
5. 5 pump housings
6. 6 intake manifold
7. 7 outlet nozzles
8. 8 fixed end wall of the pump housing
9. 9 detachable end wall of the pump housing (pump housing cover) A axis of the rotor shaft
10. 10 rotor
11. 11 gears
12. 12 rotor shaft
13. 13 rotor wing walls
14. 14 rotor wing shoes
15. 15 rotor shaft ends
16. 16 drive coupling part
17. 17 opening means
18. 18 cap
19. 19 closed bearing bushes
20. 20 stiffening ribs
21. 21 outer surface of the rotor wing shoes
22. 22 end edge of the rotor wing shoes
23. 23 sealing edge
24. 24 not used
25. 25 not used
26. 26 face
27. 27 sealing lip
28. 28 longitudinal scraping ribs
29. 29 second bearing sleeves closed
30. 30 second bearing sleeves open
31. 31 circumferential sealing lip in open bearing sleeve
32. 32 spring tongues
33. 33 latching means
34. 34 cams
35. 35 rotor shaft journals
36. 36 external thread
37. 37 internal thread
38. 38 concave inlays
39. 39 partial chambers

Claims (7)

1. Single-use rotary-piston pump made of plastics material for screwing onto a fastening nozzle on a tubular bag, having two rotors (10) which are coupled to one another via gearwheels (11), can be driven in opposite directions and are mounted in a pump housing (5), which is provided with intake nozzles (6) and outlet nozzles (7), wherein each rotor (10) has a rotor shaft (12), of which the rotor-shaft ends (15) are mounted in the walls (8, 4) of the pump housing (5) and the gearwheels are formed integrally on the rotor shafts, and wherein each rotor (10) has two rotor-wing walls (13) which are arranged diametrically on the rotor shaft (12), widen continuously outwards and at the peripheral ends of which a respective partially cylindrical rotor-wing shoe (14) is formed, wherein the rotor-wing shoes (14) butt, with sliding and sealing action, on the cylindrical inner-wall regions of the pump housing (5), on the one hand, and on the rotor-wing shafts (13) of the adjacent rotor (10), on the other hand, characterized in that seals are formed integrally on the rotor, wherein the seals serve to reduce the effects of the admission of air onto the contents located in the tubular bag.
2. Rotary-piston pump according to Patent Claim 1, characterized in that the seals comprise at least lateral sealing lips (27) on the rotor-wing walls (13), sealing/scraping edges (23) on outer surfaces (21) of the rotor-wing shoes (14) and longitudinal skimming ribs (28) on the rotor shafts (12).
3. Rotary-piston pump according to Patent Claim 1 or 2, characterized in that the pump housing (5) has a closed bearing sleeve (29) for accommodating a rotor-shaft journal (35) and an open bearing sleeve (30) for accommodating a rotor-shaft journal (35) with a drive-coupling part (16), wherein further sealing means are present in the region of the open bearing sleeve (30).
4. Rotary-piston pump according to Patent Claim 4, characterized in that the further sealing means comprise at least one encircling sealing lip (31') which is formed in one piece on a rotor-shaft journal (35), which can be inserted into the open bearing sleeve (30) of the pump housing (5).
5. Rotary-piston pump according to Patent Claim 4, characterized in that the further sealing means comprise at least one encircling sealing lip (31) which is formed in one piece on the open bearing sleeve (30).
6. Rotary-piston pump according to one of Patent Claims 1 to 5, characterized in that the outwardly continuously widening rotor-wing walls (13) with the rotor-wing shoes (14) at their peripheral ends have concave indentations (38), of which the shaping or curved progression is such that there is regularly recurring contact between the end edges (22) and the surface of the concave indentations (38).
7. Rotary-piston pump according to Patent Claim 6, characterized in that sub-chambers (39) can be formed in a quasi-permanent manner, during operation, in the intermediate region between the two rotors (10), which

   - on the one hand on account of the feature that the outer surface (21) of each rotor-wing shoe (14) of a rotor butts, during operation, against the rotor shaft (12) of the adjacent rotor (10), first partial-chamber sealing thereby being achieved, and

   - on the other hand on account of the feature that, during operation, there is also regularly recurring contact between the end edges (22) and the surface of the concave indentations (38), at least more or less second partial-chamber sealing thereby being achieved, as a result of which the effects of the admission of air onto the contents located in the tubular bag are likewise reduced by partitioning.

Images