METHOD AND APPARATUS FOR COMPACTING FLOWABLE SOLIDS

Abstract

The invention relates to a method and an apparatus for compacting flowable solids, in particular powders, flours or similar materials, preferably by packing in packagings or sacks. In order to increase the process reliability, there is provision for evacuation of the solid and its sack packaging to take place in a likewise evacuated environment.

Description

The invention relates to a method for compacting flowable solids, in particular powders, flours or like substances, preferably by packaging in packages or sacks, in accordance with the preamble of Claim 1.

The invention furthermore relates to an apparatus for compacting flowable solids.

In a process for the gravimetric dosing of bulk solids according to DE-C-19645505, a discharge apparatus is completely emptied, and the quantity of the bulk solids is determined and taken into account as blast. To that end, the discharge apparatus is run on empty at least once during the dosing process, the mass of the empty and the filled discharge apparatus is weighed, and the difference represents the blast to be taken into account.

For such discharge apparatuses, a two-shaft discharge screw conveyer is known, which has engaging spirals. The discharge screw conveyer is run with negative pressure to avoid any impairment of the guide.

The bulk solids can be de-aerated by pressing or packing, i.e. without vacuum processing, and an expansion is possible after the pressing- or packing element has been removed.

With a compacting method for flowable bulk solids according to EP-A-1561685, a compacting space is first filled with the bulk solids and then the compacting space is decreased. Then the compacting space is sealed gas-tight and subsequently increased again to generate a negative pressure. Then the compacted bulk solids flow out via an output opening.

WO-A-9007452 discloses a method for filling and evacuating large containers having a neck or a valve, for example for hygroscopic products, where the containers are filled in an evacuated chamber. The vacuum can be adapted with the addition of inert gases.

The invention is based on the problem of developing a method for compacting flowable solids, in particular powders, flours or like substances, preferably by packaging in packages or sacks, which allows the storage and transport of the compacted solids with little space requirements and stable positioning. Another goal is to reduce cost and increase process reliability.

The storage times for the compacted solids may be very long.

The object of the invention is attained with the characteristics of Patent claim 1. Because a storage chamber for a bulk solid as well as a sack chamber is evacuated before or after filling, it is possible to compact safely and to a high degree without any impairment to the flow properties of the bulk solids during the bagging. The bagging practically takes place as under “normal conditions.”

Preferred embodiments are disclosed in subordinate claims.

The compacting of white flour, for example, leads to an increase of the shelf life (no oxygen feed) and to a reduction of the packaged volume. Furthermore, it improves the stacking capability of the packaging containers and their handling and/or palletization. The growth of insects or mold as well as fatty oxidation is also inhibited.

The invention furthermore relates to an apparatus for compacting flowable solids, in particular powders, flours, or like substances, preferably by packaging into packages or sacks. The apparatus includes a storage chamber and a downstream sack chamber, both of which can be evacuated.

The vacuum is supposed to be formed as quickly as possible, if necessary with pre-vacuuming.

Furthermore, filling can also be accomplished with tubular bags, with a sack form means being used instead of a sack filler neck, and the product also being pre-weighed.

The apparatus in accordance with the invention for sacks as well as tubular bags may be integrated at individual stations as well as in carousels. Furthermore, it is possible to perform an especially advantageous staggered or preliminary vacuuming in carousels. Instead of de-aeration, the negative pressure of a preceding station may be used.

The invention is described in the following embodiment in greater detail by means of an example. The illustration shows a principal representation of the compacting apparatus.

The apparatus comprises a storage chamber 1 for flour or the like, with a sack chamber 2 located below and a slide 5 being arranged as shutoff means between the two chambers 1, 2, and with a sack filler neck 6 that projects into the sack chamber. Both chambers have a vacuum connection 4. The storage chamber 1 furthermore has a fill opening that can be sealed tightly with a lid 3.

At the neck 5 (sack filler neck), a sack to be filled (not shown) is attached in the usual manner.

Because an applied negative pressure already holds both chambers together, clamping elements are principally not required. They can be arranged for safety reasons, however.

Furthermore, certain elements (not shown) may be provided in the sack chamber 3 to lend the sack a specific form.

After the storage chamber 1 has been filled with flour for filling a sack, and a sack has been provided in the sack chamber 2 and/or at the neck 6, both chambers 1, 2 are evacuated likewise via the vacuum connection 4 while the lid 3 and the slide 5 are closed until sufficient negative pressure has been reached. Then the clamping jaws at the neck 6 are closed (the sack is attached) and the slide is opened until the sack has been filled as desired. Then the slide is closed and the sack is sealed airtight. Then both chambers 1, 2 are aerated to normal pressure, the clamping jaws at the neck are released, and the sack is moved out of the sack chamber 2 through an opening (not shown).

The neck 6 can be supplemented with a sack closing means. The storage chamber 1 has an upstream weighing and dosing means.

With a tightly closing slide 5, the storage chamber 1 alternately may also contain product for filling of a plurality of sacks, which means that the aeration and de-aeration effort can be reduced. To that end, the storage chamber 1 has a weighing- and dosing means.

REFERENCE SYMBOLS

1 Storage chamber

2 Sack chamber

3 Lid

4 Vacuum connection

5 Slide

6 Neck

Claims

1. Method for compacting flowable solids by evacuating the solids and bagging and/or packaging the solids in an evacuated container, characterized in that the evacuation of the solids and their bagging are performed in similarly evacuated environment.

2. Method in accordance with claim 1, characterized in that the evacuation of the solids and their bagging is performed in separate chambers that are connected air-tight to one another.

3. Apparatus for compacting flowable solids by evacuating the solids and bagging and/or packaging the solids in an evacuated container, characterized in that the apparatus has a storage chamber (1) for the solids and a downstream sack chamber (2) for the bagging, and both chambers (1, 2) can be evacuated and connected air-tight relative to one another.

4. Apparatus in accordance with claim 3, characterized in that a tightly sealing shutoff device is arranged between both chambers (1, 2).