EP2834521B1 - Metering pump made of plastic - Google Patents

Description

The present invention relates to a 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 exhaust nozzles, each rotor having a rotor shaft, store the rotor shaft ends in the walls of 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. However, where such metering pumps are also used to add a special amount of a liquid food to a recipe, the taste is varied by improper operation, which is not always appreciated by customers.

Although various other types of pumps are well known, especially rotor pumps, but these are usually designed as relatively high-precision, made of metal dosing pumps and this is in the food industry, where large quantities must be dispensed dosed, also required. 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 which are dispensed in so-called tubular bags or other soft packaging made of plastic films, wherein in a preferred embodiment here the metering pump is specially adapted for this purpose, as disclosed in claim 12.

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 for admixing other liquids is shown, in which case each rotor has three wing arms and these wing arms together roll over 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.

Finally, EP-1'892'417 shows a further metering pump, which is designed as an insert into an outer metallic housing, but nevertheless created for the one-time use and has a plastic housing. The gear mechanism with which the correct relative position of the two rotors is ensured, however, is part of a outside of the actual pump arranged gear and not part of the intended for one-time use parts. Sealing components in the form of lip seals for the rotor shafts are also present only as separately inserted elements. 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, the existing sealing measures concentrate because also specifically on this area.

It is therefore an object of the present invention to provide an improved metering pump with the simplest possible structure, which has a relatively large flow rate and is particularly suitable for conveying solid-liquid mixtures, without having the disadvantages described above.

This object is achieved by a metering pump made of plastic of the type mentioned, wherein each rotor has two diametrically arranged on the rotor shaft rotor blade walls, at the peripheral ends of each partially cylindrical wall is formed as a rotor blade shoe, the rotor blade on the cylindrical inner wall portions of the pump housing on the one hand and to the Rotary shafts of the adjacent rotor on the other hand rest in a sliding and sealing, the metering pump is characterized in that on each rotor shaft, a gear is integrally formed.

In a particularly preferred embodiment, each rotor blade shoe on the outside of the part-cylindrical wall at least one parallel to the rotor axis extending sealing scraping edge, which is close to the front edge in the direction of rotation respective part-cylindrical wall of the rotor blade shoe is arranged. This ensures 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.

Fig. 7

zeigt schliesslich den Einlassstutzen der Dosierpumpe mit einem Öffnungsmittel und einem Befestigungsstutzen mit Flansch zur Schweissverbindung mit einem Schlauchbeutel.

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.

Fig. 7

finally shows the inlet nozzle of the metering pump with an opening means and a mounting flange with flange for welding connection with a tubular bag.

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 is shown with a view of a fixed end wall 8 of the pump housing 5, in which case a rotor shaft end 15 with a Drive coupling part 16 provided by the aforementioned solid end wall 8 protrudes and one 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. Before the first use of the pump housing 5 with screw its intake manifold 6 into the attachment stub 3 as far as a stop, wherein said opening means 17 cut open an aseptically closed container, preferably a tubular bag made of plastic film. 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 laterally offset or shown solved. 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 end 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 integrally gears 11 are formed, which cause the two rotors when one of the two rotors is driven to 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, where one here looking at 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 Fig. The special embodiment of the rotor wing shoes 14 is particularly clearly visible in this figure. The rotor shoes 14 are integrally formed as already mentioned at the peripheral ends of the rotor blade walls 13. The rotor blade shoes have a part-cylindrical outer surface 21. The radius of curvature of this outer surface corresponds to the distance between the axis A, which passes through the rotor shaft 12 centrally in the longitudinal direction and the outer surface 21 of the rotor blade shoes.

The inventive metering pump is preferably at least practically designed so that the pump seals the connection between the intake manifold and outlet. For this purpose, the pump or its rotors and the pump housing 5 to 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, at least in the direction of rotation near the front edge in the direction of rotation, have a sealing scraping edge 23. 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 suggests, the Dichtschabkante 23 serves on the one hand, between the inner cylindrical wall parts 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. Preferably, each rotor vane shoe 14 is provided with two sealing scraping edges 23, both in the direction of the leading end edge 22 and near the trailing end edge 22. These edges are referred to both times as end edge 22, because preferably both rotors 10 are made absolutely identical so only need an 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, which preferably has a cross-sectionally approximately triangular shape causes the outer surface 21 is no longer completely rests against the inner wall of the pump housing 5. However, it also means that the rotor wing shoes 14 are deformed in the outer region. In order to facilitate this deformation and thus to achieve a resilient contact pressure of the sealing scraping edges 23, 24 joint grooves 25 are mounted on the inner surface. These hinge grooves 25 are located closer to the rotor blade walls 13 than the sealing scraping edges 23 arranged on the opposite side. The joint grooves 25 thus allow a resilient articulated movement of the corresponding end edges 22 pivotably about the hinge groove 25. Are formed on both sides of the rotor blade shoes on the outer surfaces 21 Dichtschabkanten 23, it is of course on both sides of the inner surface 24 corresponding joint grooves 25 at.

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 to the outer surface 21 of the rotor blade shoes extending a respective sealing lip 27. On the opposite end, which is not visible here, the gears 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 A of the rotor shaft. In principle, it suffices in each case to attach a longitudinal scraping rib 28 to each rotor shaft, but preferably two such longitudinal scraping ribs are respectively mounted on the same side, so that the area between two rotor blade walls 13 is approximately divided into three. This Längsabstreifrippen 28 not only act sealing, but also clean the rotor blade 14, on the outside of 21 there may be formed 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. In this solution again the pump housing cover, or the detachable end wall of the pump housing, is removed. One thus looks at the inside of the fixed end wall 8 of the pump housing. Hierin second bearing sleeves 29, 30 are formed, wherein the one second bearing sleeve 29 is designed to be closed, and the other second bearing sleeve 30 is 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.

The rotors 10 thus have on their rotor shafts 12 on both sides of rotor shaft ends 15, which are designed as a rotor shaft journal. The rotor shaft pin 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. In the Fig. 2 an alternative form for attachment of the detachable end wall 9 is shown. Here, two spring tongues are formed on the inside of the pump housing cover 9, the essential are made more stable and are practically designed as a displacement body, which penetrates in that area in the pump housing, which is not detected by the two rotors. Here it is of course also possible to provide corresponding latching means on the rotor housing. Thus, it is largely impossible in that edge area that deposits can form. Further towards the inside, the openings of intake manifold 6 and outlet 7 are present, where no deposits can form anyway. These somewhat more stable spring tongues 32 can correspondingly have latching means which are not apparent here and which can engage behind the edges of the inside of the intake stub 6 or outlet stub 7 instead of behind the cams.

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, which are designed as a bearing pin 30, as shown most clearly in the Fig. 4 is apparent.

Finally, on the Fig. 7 referenced, in which one recognizes the attachment piece 3 with the flange 4 separated from the intake manifold 6. Here, the opening means 17 are clearly visible, which are integrally formed on the intake manifold 6. The intake manifold 6 also has an external thread 36. This external thread 36 is suitable for the internal thread 37 in the attachment piece. 3

With the metering pump 1 described here, fluids and also mixtures of fluids and solids can be conveyed without problems. Here, the size of the solid particles plays It is of course of no importance that they must be of a size that is smaller 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.

Claims (13)

1. Metering pump (1), made of plastic, comprising two rotors (10), which are coupled to one another via gearwheels (11) and are drivable in opposite directions and which are mounted in a pump housing (5) provided with suction ports (6) and outlet ports (7), wherein each rotor (10) has a rotor shaft (12), the rotor shaft ends (15) of which are seated in the walls (8, 4) of the pump housing (5), and wherein each rotor (10) has two rotor blade walls (13), which are disposed diametrically on the rotor shaft (12) and onto the peripheral ends of which is respectively molded a partially cylindrical rotor blade shoe (14), wherein the rotor blade shoes (14) bear slidingly and sealingly against the cylindrical inner wall regions of the pump housing (5), on the one hand, and against the rotor blade shafts (13) of the adjacent rotor (10), on the other hand, characterized in that a gearwheel (11) is molded in one piece onto each rotor shaft (12).
2. Metering pump (1) according to Claim 1, characterized in that the pump housing (5) has an end wall (8) fixedly connected to the pump housing (5) and a thus detachable end wall (9), wherein at least one rotor shaft end (15) has a drive coupling part (16), which passes through the pump housing (5) and passes through the end wall fixedly connected to the pump housing (5).
3. Metering pump (1) according to Claim 2, characterized in that both rotors (10) are identical and both thus have a drive coupling part (16), wherein one drive coupling part (16) is seated in a second, open bearing sleeve (30) and the other is seated in an outwardly closed bearing sleeve (29).
4. Metering pump (1) according to Claim 1, characterized in that each rotor blade shoe (14) has on its outer face (21) at least one sealing scraping edge (23), which runs parallel to the rotor axis (A) and which is disposed in the region of an end edge (22) present in the rotational direction, of the respective rotor blade shoe (14).
5. Metering pump (1) according to Claim 4, characterized in that each rotor blade shoe (14) respectively has a sealing scraping edge (23), which runs parallel to the rotor axis (A) in the region of both an end edge (22) which is present in the rotational direction and one which is present in the contrarotational direction.
6. Metering pump (1) according to Claims 4 or 5, characterized in that, in the region between each sealing scraping edge (23) and the rotor blade wall (13), a joint groove (25) is disposed on the inner face (24) of the rotor blade shoe (14), i.e. on the side remote from the sealing scraping edge (13).
7. Metering pump (1) according to Claim 3, characterized in that into the second, open bearing sleeve (30) is molded, in one piece, at least one circumferential sealing lip (31).
8. Metering pump (1) according to Claim 1, characterized in that on the rotor blade walls (13), in its end sides (26) remote from the gearwheels (11), is provided at least one sealing lip (27) for sealing contact against the detachable end wall (9) of the pump housing (5).
9. Metering pump (1) according to Claim 1, characterized in that on each rotor shaft (12) is arranged at least one longitudinal stripping rib (28), which is directed radially outward and runs parallel to the rotor shaft axis (A).
10. Metering pump (1) according to Claim 9, characterized in that between the two diametrically running rotor blade walls (13), on both sides of the rotor shaft (12), are arranged two parallel longitudinal stripping ribs (28).
11. Metering pump (1) according to Claim 1, characterized in that the suction port (6) is provided with cutting and/or perforating opening means (17) and a mounting socket (3) with flange (4), which mounting socket can be welded onto a container wall.
12. Metering pump (1) according to Claim 12, characterized in that the outlet port (7) is provided with a closing cap (18).
13. Metering apparatus (1) according to Claim 3, characterized in that closed bearing bushes (19) for both rotors (10) are molded into the detachable end wall (9) of the pump housing (5).

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