GB2373242A - Emptying device for a bulk container - Google Patents

Abstract

An emptying device for a bulk container (1, Fig 1) where said container comprises a discharge hopper (2, Fig 1) and a closure member (3, Fig 1) which is moveable in an axial direction in the discharge hopper and can be moved into the closed position against the inner wall of the discharge hopper by spring action. The emptying device comprises a lifting device 15 with a pressure plate 17 which can be pressed against the pressure disc (5, Fig 2) of the closure member to move the closure member into the discharge position against the spring action, characterised in that the pressure plate is constructed to match the shape of the pressure disc so that they fit together and thus the underside of the pressure disc does not become contaminated. The pressure disc and pressure plate may be circular. An inflatable sealing ring 18 may be used to make the connection between the emptying device and the hopper airtight.

Description

Emptying device for a bulk container The invention relates to an emptying device for bulk containers in accordance with the precharacterizing clause of Claim 1.

Emptying devices of this kind are required for emptying bulk materials from bulk containers with an outlet in the form of a hopper into a storage container or the like at the intended location. For this purpose, the container containing the bulk materials is placed on an emptying station, which is generally fixed and which is matched to the outlet geometry of the bulk container and is capable of causing the bulk container to be opened and closed, allowing the bulk materials to run out of the container, even in batches, and to be fed to the associated collecting, process or storage container situated underneath the emptying station.

The emptying device mentioned at the outset for a bulk container, from which the invention starts, is known from EP 0 680 897 Bl, for example. This has a discharge hopper and closure member, which is guided in an axially displaceable manner, is held in the closed position against the inner wall of the discharge hopper, preferably by spring action, and can be acted upon by a lifting device to raise it into the discharge position. To avoid soiling, the prior art discloses that the lifting device can be produced from a single, centrally arranged cylinder, which can be moved to raise the closure member. If, however, for the emptying process, the relatively small area of a pressure plate of the lifting device situated on the discharge axis of the emptying station is pressed against a pressure disc, preferably a circular disc, of the closure member, then raises the latter and, in the process, exposes an increasing annular gap for the discharge of the filling material, it has hitherto been unavoidable that this pressure disc of the closure member should be protected against splashing by filling material and dirt following an emptying process. This is critical particularly when hazardous material or pharmaceutical products are to be dispensed, areas in which spreading of residues must be prevented for reasons of environmental protection, on the one hand, and for reasons of purity, on the other hand.

The object on which the invention was based was therefore to refine or develop an emptying device in such a way that the splashing of the pressure disc of the closure member as described no longer occurs.

This problem is solved with an emptying device which has the features of Claim 1.

Advantageous refinements of the invention are indicated by the features of the subclaims.

The invention is based on the idea of making the pressure plate of the lifting device match with the pressure disc of the closure member. In this way, the emptying process is screened from the underside of the bulk container, thus preventing splashing of the latter, especially of the closure member.

In order to protect the underside of the bulk container and especially also its outer wall from splashing, a sealing device is preferably provided, with which the lower edge region of the discharge hopper can be brought into sealing contact in a positive-interlock manner.

It is furthermore advantageous if a discharge tube directly adjoins the sealing device in order to carry away directly the material to be emptied. Soiling or contamination of other external parts of the bulk container is avoided by means of this measure.

A particularly advantageous variant of simple design consists in making both the pressure disc of the closure member and the pressure plate of the emptying device of (matching) circular design.

Provision is furthermore made for the sealing device to have an annular inflatable seal in the region of the discharge hopper, of the type described in DE 196 45 904 Al, for example. A positive interlock and thus leaktight closure is formed in this way.

Provision is furthermore made for centring devices to be provided in order for the small container to be placed fitting accurately on the emptying station.

The invention is explained in greater detail below with reference to the exemplary embodiments illustrated diagrammatically in the figures, of which: Fig. 1 shows a partially sectioned view of a bulk container; Fig. 2 shows the outlet of the bulk container in accordance with Fig. 1 in section; and Fig. 3 shows an emptying station according to the invention in section.

An emptying device 14 according to the invention for a bulk container 1 will now be described below with the aid of Figures 1 to 3.

Figure 1 shows a bulk container 1 of a type known per se. A bulk container 1 of this kind has a main body which is closed off at the top with the aid of a cover. Adjoining the underside of this cylindrical main body is a so-called discharge hopper 2, which is in the form of a radially symmetrical truncated cone. The bottom end of this discharge hopper 2 can be closed with the aid of a suitable closure member 3. For particulars of the construction of a closing device of this kind and the operation of the closing mechanism of the bulk container, attention is drawn to the explanations in EP 0 680 897 Bl.

Figure 2 shows an apparatus for closing (and opening) the closure member 3 referred to above. This apparatus is also referred to as a discharge cone 13 owing to its characteristic shape. As can be seen from Figure 2, a conical closure-member holder 9 is supported on the inside of the discharge hopper 2.

This closure-member holder 9 carries an axially arranged spiral-spring holder 10. Supported against this spiral-spring holder 10 is a return spring 4 in the form of a spiral spring, which is guided in an axially displaceable manner in an axially arranged hollow cylinder 11. At the other end, the return spring 4 is supported against the actual closure member 3, which is designed as a circular pressure disc 5 in the example. The closure member 3 with the circular pressure disc 5 is guided in an axially displaceable manner in the discharge hopper 2, on the outer wall of the hollow cylinder 11, by means of guide elements 12 of annular design.

In the closed position illustrated here, the outer rim of the circular closing plate 5 is held pressed against the inner wall of the discharge hopper 2 by the spring action of the return spring 4. To produce a highly effective sealing action, a sealing ring 6 is arranged on the outer rim of the circular pressure disc 5.

To move the closure member 3 into the discharge position, a lifting device 15 is arranged underneath the closure member 3 according to the prior art, this device being provided for the purpose of raising the closure member 3 to expose an annular gap and allow the bulk materials to be discharged downwards through this annular gap. The annular gap is not shown explicitly in the drawings provided here but attention is drawn, by way of example, in this regard to Figures 4 and 5 in EP 0 680 897 Bl.

The lifting device 15 is part of an emptying station 20 of the type illustrated in Figure 3. This emptying station 20 comprises a supporting stand or the like, which has an accommodation space 16 for a bulk container 1 on its upper side. In Figure 3, the standard feet 8 and the bottom part of the holding stand 7 (c. f. the illustration in Figure 1) for the actual bulk container 1 are sketched in broken lines.

The lifting device 15 for raising the closure member 3 is situated in the central area of this emptying station 20. This lifting device 15, which is preferably designed as a pneumatic or hydraulic cylinder, is supported by a discharge tube 19, which tapers downwards and is itself secured on the support arrangement of the emptying station 20. The discharge tube 19 opens into a conically widened portion on the side facing the bulk container 1. This portion forms an area of overlap for the bottom end of the discharge hopper 2 of the small container 1. To avoid mechanical damage and, especially, to achieve positive-interlock contact, the cone-type portion is equipped with an inflatable sealing ring 18, which is constructed in the manner of a tube which can be inflated with the aid of a pneumatic device. For details of the particular configuration of an inflatable sealing ring 18, reference may be made to the explanations in DE 196 45 904 Al. However, as is apparent from EP 0 680 887 Bl, for example, it can also be designed as a sealing sleeve.

In order to move the closure member 3 into the discharge position, it is, as already indicated, raised by the lifting device 15, that is to say, in particular, the axially arranged cylinder. The special inventive feature of this lifting device 15 is that it has a pressure plate 17 which is constructed essentially to match to the underside of the closure member 3, i. e. the surface of the pressure disc 5. The matching embodiment of the pressure disc 5 and the pressure plate 17 reliably prevents splashing of the pressure disc 5 while the bulk container 1 is being emptied, thus preventing subsequent dripping from the underside of this pressure plate 5 or contamination of a component or the like brought into contact with the pressure disc 5.

Provision is furthermore made for the inflatable sealing ring 18 preferably to completely surround the bottom end region of the discharge hopper 2, with the result that the latter does not project beyond the inflatable sealing ring 18 at the end face. This ensures that, during the emptying process, no part of the outer wall and, in particular, the underside of the bulk container 1, comes into contact with the filling material. The discharge tube 19, which directly adjoins the inflatable sealing ring 18 and carries away from the bulk container 1 the material to be emptied, also serves the same purpose. The actual emptying process thus takes place only at the tapering bottom end of this discharge tube 19, thereby avoiding any soiling or contamination of the bulk container 1. List of reference numerals: 1 Bulk container 2 Discharge hopper 3 Closure member 4 Return spring 5 Pressure disc 6 Sealing ring 7 Holding stand 8 Standard foot 9 Closure-member holder 10 Spiral-spring holder 11 Hollow cylinder 12 Guide elements 13 Discharge cone 14 Emptying device 15 Lifting device 16 Accommodation space 17 Pressure plate 18 Inflatable sealing ring 19 Discharge tube 20 Emptying station

Claims (6)

1. Claims 1. Emptying device (14) for a bulk container (1), with a discharge hopper (2) and a closure member (3), which device is guided in an axially displaceable manner in the discharge hopper (2) and can be moved into the closed position against the inner wall of the discharge hopper (2) by spring action, with a lifting device (15) with a pressure plate (17), which can be pressed against the pressure disc (5) of the closure member (3) to move the closure member (3) into the discharge position against the spring action, characterised in that the pressure plate (17) is constructed essentially to match with the pressure disc (5).
2. 2. Emptying device (14) according to Claim 1, characterised in that a sealing device (18) is provided for sealing contact with the discharge hopper (2).
3. 3. Emptying device (14) according to Claim 2, characterised in that the sealing device is designed as an inflatable sealing ring (18), as a sealing sleeve or the like.
4. 4. Emptying device (14) according to Claim 1,2 or 3, characterised in that provision is made for a discharge tube (19) which adjoins the sealing device (18).
5. 5. Emptying device (14) according to one of Claims 1 to 4, characterised in that the pressure plate (17) and the pressure disc (5) are of circular design.
6. 6. Emptying device (14) according to one of Claims 1 to 5, characterised in that centring devices are provided in order to ensure that the bulk containers (1) are placed fitting accurately one on top of the other.