EP0297371B1 - Dosing device for powder - Google Patents

Abstract

The device has a receiving container and a rinsing-out space for the apportioned metering of, in particular, powdery cleaning material from the receiving container into the rinsing-out space for supplying industrial dishwashers or washing machines. A solution is to be provided which allows the metering both of satisfactorily pourable powder cleaners and of powder cleaners with lumps and the like, whilst always achieving essentially the same metering capacity even with different levels of the powder cleaner in the receiving container and additionally reducing the risk of moisture entering the receiving container from the rinsing-out space. This is achieved by metering holes (9) in the bottom (8) of the receiving container (2) and in each case a collection plate (10), arranged with spacing below the metering holes (9), and a scraping mechanism (11) which is movable in the space between the underside of the bottom (8) and the collection plates (10) and essentially wipes over the plate surfaces. <IMAGE>

Description

The invention relates to a device consisting of a storage container with an associated wiping mechanism and a rinsing space with water inlet and water outlet for portioned metering of, in particular, powdered cleaning material from the storage container into the rinsing space for loading commercial dishwashers or washing machines, with at least one in the bottom of the storage container Dosing hole is formed and at least one collecting plate is provided at a distance below the at least one dosing hole.

Such a powder metering device is preferably used in commercial dishwashers or washing machines. In such machines, the detergent or detergent is permanently kept in such a large quantity in a storage container that the detergent is to be added to the fresh water or circulating water automatically when required. For example, a powder product metered into a rinsing basin of a commercial dishwasher for pre-metering is fed with cold or warm fresh water and for post-metering with warm circulating water via a solenoid valve Slope washed into the tank to be dosed in the machine to be supplied. In this context, dosing devices have been created that allow powdered cleaning agents to be introduced into the rinsing space in a controlled manner. Difficulties arise when the powder cleaner has become clumped, clammy or pasty due to atmospheric moisture, so that the metering mechanism cannot have the intended effect. In powder cleaners, a large amount of detergent is often poured into a storage container, so that the metering unit decreases as the storage container is emptied due to the decreasing product pressure with gradual consumption.

From US-A-3 066 520 a generic device is known, in which the connection path from the storage container through the dosing hole into the rinsing space is closed for dosing purposes by means of a piston-like rod.

Furthermore, from DE-A-2 715 369 a powder metering device is known which consists of a storage container and a rinsing space located underneath. In this case, the bottom of the storage container is formed by a rake which meshes with a rotatably mounted rake and in this way conveys powder product from the storage container into the rinsing space.

The object of the invention is to provide a solution that allows both the metering of perfectly free-flowing and powder cleaner with clods, lumps and the like, always substantially the same metering performance even at different levels of the powder cleaner in the storage container achieved and in addition the risk of moisture penetrating from the rinsing space into the storage container is reduced.

In a device of the type mentioned, this object is achieved according to the invention in that in the space between the underside of the floor and the at least one collecting plate, a movable stripping mechanism is provided which essentially extends across the plate surface, and in that the device has several metering holes and collecting plates, and the passage cross-section of the metering holes, the vertical distance between the underside of the bottom and the collecting plates and the area of the latter in the area below the metering holes are adapted to one another in accordance with the angle of repose of the cleaning powder such that the passage between the storage container and rinsing space is blocked by pre-metered cleaning agent when the scraper mechanism is at a standstill is.

The dosing holes in the bottom of the storage container allow cleaning powder to trickle through from the storage container onto the collecting plate located under each dosing hole. Here, as much powder product trickles through the individual metering hole until a truncated cone-shaped unit with a slope corresponding to the angle of repose hits the edge of the metering hole. Additional powder can only flow down through a hole when existing portioned product quantities have been pushed aside between the underside of the base and the collecting plates. The passage cross-section of the metering holes, the vertical distance between the underside of the bottom and the collecting plates and the area of the latter in the area below the metering holes are matched to one another in accordance with the angle of repose of the cleaning powder so that the passage between the storage container and the rinsing space is blocked by pre-metered cleaning powder when the scraper mechanism is at a standstill . In this way, a self-locking metering mechanism is created. Only when that Existing portioned product quantity between the underside of the base and the collecting plates has been pushed aside by the scraping mechanism which is movable in the space between the underside of the base and the collecting plates and essentially sweeps over the entire plate surface, further powder can flow in.

In principle, according to the invention, pre-metering is carried out in the form of frustoconical units and, if necessary, the pre-metered product is fed to the intended use with the aid of a scraper mechanism. Without actuation of the stripping mechanism, on the other hand, the pre-metered product quantities themselves form a seal between the adjacent part of the interior of the machine and the storage container containing the further powder product, which also prevents the penetration of moisture from the rinsing space into the storage container. Since the powder filling of the storage container is supported and held by the floor apart from the dosing holes, the level of the powder still in the storage container has no significant effect on the dosing performance. Finally, the metering holes can be made so large and / or a stirrer can be provided to distribute the cleaning powder on the floor in such a way that even powder clods that are clumped or clumped are easily accessible to the metering mechanism.

According to an embodiment of the invention, the scraper mechanism of the collecting plate consists of at least one metering finger rotatably mounted about the vertical axis, about which metering holes and collecting plate are to be distributed essentially symmetrically. When using three dosing holes and three collecting plates, it may be advantageous for a uniform dosing to use a wiper mechanism consisting of four dosing fingers that are symmetrical to the axis to provide. A form of the collecting plate which is simple to manufacture consists of circular sectors which are attached to the vertical axis and are spaced apart in the circumferential direction, each vertically below the metering hole.

According to a further embodiment of the invention, a trough, preferably symmetrical with respect to the vertical axis, is provided in the bottom of the storage container, in the bottom surface of which the metering holes are located. Stirrers with one or more stirring fingers can be provided rotatably about the vertical axis directly above the metering holes, inside the trough and possibly additionally or instead directly on the bottom of the storage container surrounding the trough. With the help of these stirrers, more or less heavily baked powder product can be easily and continuously introduced into the metering holes when the scraper mechanism located below the bottom is in operation.

Reliable powder dosing is guaranteed by the powder quantities portioned onto the collecting plates and the dynamic forced clearing of the collecting plates with the help of the scraper mechanism. If there is a risk that moist powder product will accumulate on the stripping surfaces of the stripping mechanism, these dosing means are stripped regularly, for example once each time on a bow spring or the like.

The scraper mechanism is designed in such a way that it can effortlessly clear incrusted and hardened powder cones on the collecting plates after switching on after switching on in the downstream rinsing area.

In a further development of the invention, an electric motor, in particular a shaded-pole motor with gear reduction, is provided as the drive for the metering and stirring mechanism, the drive shaft of which should lie in the vertical axis of metering holes and collecting plates. The drive can be arranged as a closed block below the rinsing space so that the space above the metering device remains free for placing a commercially available powder container.

The bottom of the storage container and the moving parts of the scraper mechanism and stirrer including the associated axis should preferably be made of stainless steel, V 4, because of the aggressiveness of the cleaner used and the required stability of the moving parts. The collecting plate and the bottom of the rinsing space, on the other hand, can essentially be made of plastic which is also resistant to the aggressive cleaning powder, e.g. PE or PP.

In order to enable observation of the powder supply in the storage container, the invention further provides that the storage container consists of transparent plastic.

In order to further reduce the risk of moisture penetrating into the storage container, the invention provides, in a further embodiment, a chimney-type fume hood arranged on the rinsing space above the water outlet. This is particularly expedient in the case of a device with a rinsing space through which circulating water flows permanently.

The effect of the vapor extraction is strengthened and supported by one arranged in the transition from the rinsing space to the vapor extraction Air baffle with aerodynamically designed flow-around edge and air slots formed in the side walls of the rinsing space, as is also provided by the invention. Through the air baffle and the air slots, an air flow is generated in cooperation with the fume hood in the rinsing space, which draws any moisture mist into the fume hood, so that the moisture is kept away from the metering mechanism. The air baffle is designed in such a way that moisture, which is deposited thereon, collects in the area around the flow edge and is then entrained by the air flow into the fume hood. The louvers are arranged at a height that is significantly above the normal liquid level in the rinsing space.

In order to avoid the formation of splash water and to achieve a regulated flow of the liquid in the rinsing space, the device according to the invention is characterized in further development in that a cross-sectionally essentially diamond-shaped guide core is arranged in the rinsing space, comprising the drive shaft for the stirrer.

According to a further embodiment of the invention, the circulating water is supplied in a particularly gentle manner and with restraint of any food residues carried along by a circulating water supply device designed as a water valve lip in the rinsing space.

Finally, the invention provides in a further embodiment at least one electrode arranged in the area of the water drain for detecting the water level in the rinsing space.

Figur 1

einen senkrechten Schnitt durch eine erfindungsgemäße Vorrichtung,

Fig. 2

eine Aufsicht auf die Dosiermechanik längs der Schnittlinie II - II von Fig. 1,

Fig. 3

eine Aufsicht auf die Dosiermechanik längs der Schnittlinie III - III und in

Fig. 4

eine Aufsicht auf den Leitkern längs der Schnittlinie IV - IV.

The invention is explained below with reference to the schematic drawing, for example. This shows in

Figure 1

a vertical section through a device according to the invention,

Fig. 2

a view of the metering mechanism along the section line II - II of Fig. 1,

Fig. 3

a supervision of the dosing mechanism along the section line III - III and in

Fig. 4

a supervision of the guide core along the section line IV - IV.

The device shown in FIGS. 1 to 4 and generally designated 1 consists of a storage container 2, a rinsing space 3 and a metering mechanism arranged between them. The storage container 2 is so large or suitable that it is suitable for receiving an original container. It has a lid 4 and can therefore be closed on its upper side against the ingress of moisture. At the bottom of the storage container (not shown), means for opening, for example piercing, an unopened original package placed in the container can be provided.

In the exemplary embodiment, the base 5, which preferably consists of V 4 A stainless steel and is inclined in the direction of the central axis 6 of the container 2, contains a trough 7 in the center, in the base 8 of which 8 metering holes 9 are provided. Underneath each metering hole there is also a sector-shaped collecting plate 10. Three metering holes 9 and collecting plate 10 are expediently arranged almost symmetrically on a pitch circle with respect to the central axis 6.

Between the bottom 8 of the trough 7 and the collecting plates 10, a scraper mechanism 11, for example consisting of four metering fingers 12, is provided rotatably about the central axis 6. In the exemplary embodiment, a stirrer 13 consisting of two groups 14 and 15 of stirrer fingers is rotatably arranged about the central axis 6 above the base 8 of the trough 7. The stirring fingers 14 are moved within the trough 7, while the stirring fingers 15 also sweep the bottom 5 of the storage container 2 surrounding the trough 7. By means of the stirrer 13 it is achieved that even moistened or clumped powder product present in clods can be reliably introduced into the metering holes 9 and metered.

During operation, powder product falls through the metering holes 9 onto the collecting plate 10 and remains there as a truncated cone-shaped metering unit 16. If cleaning agent is required in the downstream machine, the wiping mechanism 11 is switched on in such a way that the dosing fingers scrape off the dosing units 18, which are in the shape of a truncated cone on the collecting plates 10, over the respective radially extending edge 17 of the collecting plate 10 in a rinsing space 3 which is arranged underneath and is designed as a rinsing trough . At the same time, the metering holes 9 are permanently supplied with powder product 18 with the rotating stirring fingers 14, 15 via the trough 7 with the bottom surface 5 of the storage container 2 inclined towards the center. In order to prevent excessive powder coating of the stripping surfaces of the metering fingers 12, the metering fingers 12 are stripped once by a bow spring 19 with each revolution.

The powder product dosed into the rinsing space 3 is by means of a water distribution lip 20, which is supplied with circulating water at a temperature of approximately 60 ° C., via a gradient and then through the water outlet 21, which is a centrifugal pump (not shown here) or an injector is connected downstream, for example to a dishwasher. If desired, cold or warm fresh water can also be supplied to the rinsing space 3 via a nozzle 25. Is the Device 1 assigned to a washing machine, only cold fresh water is supplied to the rinsing space 3.

To drive the stirrer 13 and the stripping mechanism 11, an electric motor 22 with a reduction gear 23 is expediently provided below the rinsing space 3 for reasons of space. The drive via shafts located in the central axis 6 can be designed and controlled such that either the stirrer 13 and the stripping mechanism 11 rotate together, or that the stirrer 13 is permanent and the stripping mechanism 11 is to be rotated whenever cleaning agents are required.

If in the bottom 8 of the trough 7 three metering holes 9 are to be provided, z. B. the following dimensions in question:
Diameter of the dosing holes = 18mm
Radius of the bolt circle = 31mm
Sector size of the collecting plate = 80 °
Distance collecting tray / floor = 10mm

The water distribution lip 20 is designed so that it distributes the circulating water flowing in evenly over the bottom surface of the rinsing space 3. Any food residues carried in the circulating water can, however, detach themselves from the water distribution lip 20, which is movably mounted on an axis 26, and flow back to the dishwasher through the water outlet 21.

A chimney-like vapor extraction shaft 27 is arranged on the device 1 above the water outlet 21 in order to discharge water vapor-shaped vapors formed when the circulating water at approximately 60 ° C. is flushed in. In the side walls of the rinsing space 3 there are air slots 28, one of which is shown in broken lines in FIG. Together with the fresh air flowing in through the louvers 28, they are in the Flushing vapors 3 are taken up by the vapor extraction duct 27 and discharged into the environment. In order to prevent swirling of vapors and air through edges and surfaces on the dosing mechanism in the area of the rinsing area, these are aerodynamically designed in the direction of flow. In particular, an air baffle 29 with an aerodynamically designed flow-around edge 30 is arranged in the transition region from the rinsing space 3 to the vapor extraction shaft 27. An air flow is generated by the vapor extraction shaft 27, the air slots 28 and the air baffle 29, which prevents moisture from being deposited in the area of the metering mechanism.

In the area of the line 24, a carbon flow electrode 31 for measuring the conductivity of the incoming circulating water is installed below the rinsing space 3. If the conductivity value falls below a specified value, the wiping mechanism 11 is started and cleaning powder is metered into the rinsing space. However, it can also be provided to assign a time relay to the stripping mechanism 11, with the aid of which the stripping mechanism 11 is actuated automatically at certain time intervals, since the device according to the invention is exceptionally well suited for precise time / quantity control.

Finally, two electrodes 32 for detecting the water level in the rinsing space are provided within the rinsing space 3 in the area of the water outlet 21. If the liquid level is too high, the higher electrode switches off the water supply, and the lower electrode switches off the electric motor 22 if the liquid level in the rinsing space 3 is too low.

Furthermore, in the rinsing space 3 around the drive shaft for the stirrer 13, a cross-sectionally essentially diamond-shaped guide core 33 is arranged, around which the incoming water flows in the direction of the arrow according to FIG. 4.

Finally, the cover 4 is also assigned a safety switch 34, which prevents the metering mechanism from being switched on or the supply of water when the cover is not closed.

Claims (22)

1. Device (1) consisting of a provisional storage container (2) with associated wiping-off mechanism (11) and a flushing chamber (3) with water inlet and water outlet (21) for the portioned admetering of, in particular powdery cleaning material (18) from the provisional storage container (2) into the flushing chamber (3) for the charging of industrial rinsing or washing machines, wherein at least one metering hole (9) is formed in the base (5, 8) of the provisional storage container (2) and at least one respective collecting plate (10) is provided, which is arranged at a spacing below the at least one metering hole (9), characterised thereby, that a movable wiping-off mechanism (11), which substantially wipes across the plate surface, is provided in the space between the underside of the base (5, 8) and the at least one collecting plate (10) and that the device (1) comprises several metering holes (9) and collecting plates (10) and the passage cross-section of the metering holes (9), the vertical spacing between the underside of the base (8) and the collecting plates (10) as well as the area of the latter in the region underneath the metering holes (9) are so matched one to the other in correspondence with the angle of repose of the cleaning powder that the passage between the provisional storage container (2) and the flushing chamber (3) is blocked by preliminarily metered cleaning agent when the wiping-off mechanism (11) is at standstill.
2. Device according to claim 1, characterised thereby, that the metering holes (9) and the collecting plates (10) are distributed substantially in symmetry with respect to a vertical axis (6).
3. Device according to claim 1 or 2, characterised thereby, that the wiping-off mechanism (11) consists of at least one metering finger (12), which is borne to be rotatable about the vertical axis (6).
4. Device according to one or more of the claims 1 to 3, characterised thereby, that at least one stirrer (13 to 15) for the distribution of the cleaning powder (18) is provided at the base (8) above the metering holes (9).
5. Device according to claim 4, characterised thereby, that the stirrer (13) consists of at least one stirring finger (14, 15), which is borne to be rotatable about the vertical axis (6).
6. Device according to one or more of the claims 2 to 5, characterised thereby, that the metering holes (9) are situated in the base (8) of a pan (7), which is let into the base area (5) of the provisional storage container (2) and symmetrical with respect to the vertical axis (6).
7. Device according to claim 6, characterised thereby, that the stirrer (14) is rotatable in the pan (7).
8. Device according to claim 6 or 7, characterised thereby, that three metering holes (9) are provided on a pitch circle in the base (8) of the pan (7).
9. Device according to one or more of the claims 6 to 8, characterised thereby, that the collecting plates (10) are formed as circular sectors which are set at a spacing in circumferential direction and fastened at the vertical axis (6).
10. Device according to one or more of the claims 1 to 10, characterised thereby, that the wiping-off mechanism (11) is associated with a cleaning device, in particular a clip spring (19) or the like, which during each revolution wipes off once adhering powder.
11. Device according to one of more of the claims 2 to 10, characterised thereby, that the drive of the wiping-off mechanism (11) and the stirrer (13) consists of an electrical motor (22), in particular a shaded pole motor with step-down gearing (23), wherein the drive shaft lies in the vertical axis (6).
12. Device according to claim 11, characterised thereby, that the drive is arranged as self-contained block underneath the flushing chamber (3), which is preferably constructed as flushing trough.
13. Device according to one or more of the claims 1 to 12, characterised by the construction of the base (5, 8) of the provisional storage container (2) and the movable parts of the wiping-off mechanism (11) and the stirrer (13) inclusive of associated shafts of fine steel.
14. Device according to one or more of the claims 1 to 12, characterised thereby, that the collecting plates (10) and the base of the flushing chamber (3) consist substantially of synthetic material.
15. Device according to one or more of the claims 1 to 14, characterised thereby, that the provisional storage container (2) is constructed for the reception of an original package.
16. Device according to one of the preceding claims, characterised thereby, that the provisional storage container (2) consists of transparent synthetic material.
17. Device according to one of the preceding claims, characterised by a chimney-like vapour extraction shaft (27) arranged above the water outlet (21) at the flushing chamber (3).
18. Device according to one of the preceding claims, characterised by a metal air guide plate (29) with aerodynamically shaped flow edge (30) and arranged in the transition from the flushing chamber (3) to the vapour extraction shaft (27).
19. Device according to one of the preceding claims, characterised by air slots (28) formed in the side walls of the flushing chamber (3).
20. Device according to one of the preceding claims, characterised thereby, that a guide core (33), which is substantially rhomboid in cross-section and encompasses the drive shaft for the stirrer (13), is arranged in the flushing chamber (3).
21. Device according to one of the preceding claims, characterised by a circulation water feed equipment, which is constructed as water-distributing lip, in the flushing chamber (3).
22. Device according to one of the preceding claims, characterised by at least one electrode (32), which is arranged in the region of the water outlet (21), for the detection of the water level in the flushing chamber (3).

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