DE3111612A1 - APPLICATION OF VACUUM FILM PACKAGING FOR PACKING ALUMINOTHERMAL MIXTURES - Google Patents

Description

Ol I IUIZ.

Elektro - Thermit GmbH, Essen

Use of vacuum film packaging for packaging aluminothermic mixtures

Summary: Page 2 Claim: Page 3 Description: Page 4 bis

Aluminothermic mixtures consist of finely divided. Aluminum and heavy metal oxides, wherein the mixture to dampen the reaction and / or to form ^one of an alloy in the reaction, further finely divided metals, metal oxides or other alloying elements, such as iron filings, copper, copper oxides, chromium, manganese, carbon or the like. can be added.

To achieve a uniform reaction and to do it controlled process, it is necessary that the reactants contained in the aluminotherraischen mixture be within a predetermined particle size range and with a desired particle size distribution.

The different specific weights of the reactants in the aluminothermic mixture as well as their specific ones Particle shape cause during transport and storage, especially when subjected to shaking loads, such as they cannot be ruled out during loading and transport, changes in production optimally set mixing ratio of the reactants within a packaging unit, e.g. a cloth bag containing 7 to 15 kg of aluminothermic mixture as the usual form of packaging for aluminothermic *: - Welding compounds for performing aluminothermic schion welds.

JIIIbIZ

This segregation can lead to an uneven course of the aluminothermic reaction. Is e.g. at the aluminothermic rail welding the reaction due to segregation in the reaction crucible, which is open at the top, is too violent or uneven, e.g. a part the melt are thrown out of the crucible, whereby the operating personnel is endangered and it in addition, faulty welds due to missing weld metal or the formation of alloys are undesirable Composition can come. Separated aluminothermic mixtures can also react too slowly, which can lead to heat losses and thus also to faulty welds. Since the vast majority of the aluminothermic mixtures for rail joint welding is used, such sources of error have to be ruled out for reasons of road safety will.

Attempts have been made to counteract the segregation of aluminothermic mixtures by pelletizing the reactants. However, this requires inorganic or organic binders. A possible inorganic binder is water glass, with which the aluminothermic mixtures could be made into a paste and solidified _{with CO 2.} However, this introduces foreign elements into the reaction mixture, which interfere with the molten metal

can. If organic binders are used, the organic constituents can contribute to the development of gas the reaction and thus lead to porous reaction products. Another disadvantage of pelletized mixtures but lies in the increase in the bulk volume. By the sudden development of heat in the aluminothermic reaction expands that contained in the bed Air strongly and causes violent splashing of the reaction mass at the beginning of the reaction.

The invention is now based on the object of a simple solution to the problem of preventing segregation · to find aluminothermic mixtures optimally mixed during production without adding any substances to the mixture must be added, which remain in the aluminothermic reaction or interfere if they remain. In particular, the bulk density of the reaction mixture should; - " cannot be decreased. All application properties of the Bollen aluminothormic mixture remain unchanged stay.

According to the invention, this object can surprisingly be achieved by using the vacuum foil packaging from alui:> i "■ --thermalischen Mixtures are dissolved.

The packaging of powdery or granular goods in packaging containers, which are essentially thermo

Plastic foils are formed and the air is removed from the packaging unit by applying a vacuum removed after filling has long been known. Such vacuum film packaging have in particular gained importance in the packaging of food. This type of packaging essentially solved two tasks:

a) By removing the air from the packaging unit, e.g. that made of plastic film "Bags, the volume of the filled packaging unit is kept to a minimum, so that the largest possible Number of packaging units transported and / or stored in a given volume

j can be.

b) By removing the air from the packaging unit, decomposition processes are caused by oxygen reduced or avoided. This is why this process has been used, for example, for packing ground, freshly used roasted coffee and achieved that the container has the smallest possible volume and on the other hand the aromas of the coffee are retained. The consumer is also others, in the same way packaged foods, such as vacuum-packed peanuts.

One has also using the vacuum foil cUunn industrial granular or powdery goods packaged,

the primary goal being that the filling material has the highest possible bulk density. For this reason, the bulk goods were usually shaken during or after packing condensed. A device suitable for this is described, for example, in DE-AS 11 43 434.

The application of this vacuum packaging, which is known per se, to aluminothermic mixtures is inventive Character in that a completely different and unpredictable effect with this type of packaging can be achieved. By packing the aluminothermic mixture in a flexible container, in particular a bag or sack made of plastic film which, after evacuation, fits tightly around the aluminothermic mixture and this encloses, the aluminothermic mixture is compressed and solidified so that by shaking movements a segregation of the aluminothrmii optimally mixed during production during transport and storage: · one Mixture no longer takes place.

The particular advantage here is that the aluminothermic mixture does not contain any solidifying E'reradsuL · .-. > an -: must be added, which in the later alumino the ri ^; ■ - · ■. Reaction by influencing the molten metal or 'uii formed slag could interfere. When the (- bond is torn open, the previously compact aluminothermic mixture becomes

• · · 1

immediately free-flowing again and can be poured into the reaction crucible.

Vacuum film packaging is therefore particularly suitable for aluminothermic mixtures if they have to be transported over long distances with different means of transport. Such long transport routes are quite common when shipping aluminothermic mixtures, since these mixtures are manufactured in specialized companies, whereby the place of manufacture and the place of use can be quite far apart. These mixtures are transported by motor vehicle, train, ship and occasionally also by airplane. The majority of aluminothermic compounds are used for rail joint welding in railroad tracks. The aluminothermic mixtures must therefore be transported to the track to be welded on construction site vehicles immediately before they are used. It is understandable that segregation, aluminothermic mixtures, could not be avoided with conventional packaging, e.g. in linen bags, with these transport loads favors / that the components of the mixture are very different specifically. Weights and different particle sizes and particles ·., · - shape.

3 111 6 Ί 2

By using the vacuum film packaging according to the invention succeeds in preventing this segregation process practically completely.

To produce the packaging units, from the Packaging films known from the prior art, in particular thermoplastic films, can be used. You need to only meet the condition that they allow a substantially vacuum-tight packaging. Suitable Films are, in particular, films made of polyethylene, with film thicknesses of 0.1 to 0.3 mm being preferred. Thermoplastic Foils have the advantage that they can be sealed in a vacuum-tight manner in a simple manner by welding permit.

In order to achieve a higher mechanical stability, the films can be provided with additional packaging material, e.g. paper, such as soda kraft paper, can be laminated. The packaging material must, however, also after the Lamination be flexible that it is dos Vacuum tightly around the aluminothermic ^ mixture and clings to this.

It is also possible to use films which shrink through heat treatment. In this case, the aluminothermic mixture is first poured into one of the FoI \ c

ί .- ·. .: 3 1 Ί Ί 6 Ί λ

AO

The bag formed is filled and the bag is hermetically sealed after the vacuum has been applied. The packaging unit thus obtained can then be heated by · warm air or by immersing in a heated liquid, such as Water, in addition to being shrunk.

The aluminothermic mixture packaged according to the invention is solidified into a hard, rigid block from which the aluminothermic Mixture can be recovered in giant shape.

Claims (1)

i 0 ψ · · Patent claim Application of vacuum film packaging for packaging aluminothermic mixtures.