FI92818C - Production method for the clay pigeon - Google Patents

Description

92818 METHOD OF MANUFACTURE CLAY DISK

The invention relates to a manufacturing method for the production of disposable paints, such as clay discs, used in shotgun shooting or the like.

Clay discs are internationally standardized in their main dimensions and weight. They are disc-shaped in shape and have a circular bottom projection. Clay discs are intended as mobile shooting targets for sports-10 bats and hunters. In practice, clay discs are thrown into air-moving paints by machine or by hand and broken by firing. This approach places great demands on the material properties of the clay discs, as they 15 must be able to withstand the stresses caused to them by transport and the throwing device, but on the other hand they must break into small pieces when a single shot is hit.

The method of manufacturing clay wafers currently in use is described in Finnish publication No. 46208, which uses a mixture of pitch-like substance and filler. The mixture is melted by applying heat to it, after which it is compressed in cooled molds. The mixture contains mainly 50% by weight of coal tar pitch with a softening point of 85-90 ° C and 50% of calcium carbonate. However, this production method contains a very serious health disadvantage, as coal tar pitch contains high concentrations of polycondensed aromatic hydrocarbons, e.g. carcinogenic 3,4-benzopyrene.

30 If the discs break as a result of the shots, this harmful dust will spread to nature and it is possible that the animals in the area will consume it with their food and may become ill. In addition, given that thousands of clay discs are broken in one race, there are 35 health considerations to consider.

Swedish Offenlegungsschrift No. 398267 discloses a process for the preparation of 9281 8 2 in which, in order to reduce the above-mentioned disadvantages, aromatic petroleum resins having an atomic ratio of carbon to hydrogen of 0.8 or more and an average molecular weight of more than 1500 and a boiling point of at least 300 ° C are used as binders.

German Patent Publication No. 2627695 discloses the preparation of wafers from thermoplastic resins, kerosene-10 resins, terpene resins, polyterpene resins, xylene resins and polystyrene or modifications thereof with a powdered filler. Dust generated by the rupture of resin wafers is also unhealthy. For example, bakelite dust has been found to cause changes in the lungs. In addition, polycyclic hydrocarbons, asphalt, bitumen-based oils can cause skin cancer. A common disadvantage of the above inventions is their nature-polluting property.

20 Indeed, German Patent Publication No. 270236 describes the manufacture of clay wafers from a non-environmentally hazardous substance, such as a fertilizer, in order to avoid the release of substances harmful to nature. This was already taken into account in 1913, but it was not yet possible to implement it in practice.

According to Swiss Patent No. 541796, it is known to produce hollow-body, thin-walled target paints by freezing water on site. However, the manufacturing method is difficult to implement in practice, as each shooting range would then require its own production equipment. In addition, the number of firing discs in a given period is so large that these needs cannot be met by that method. This manufacturing method must also take into account the cheapness of the raw material and the correspondingly high energy requirements for the manufacture.

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Finnish publication No. 59872 discloses a manufacturing method in which waste gypsum generated in the process of a phosphoric acid plant and ash generated in connection with the incineration of waste liquor from a cellulose plant are used as the basic raw material for clay wafers. According to the invention, a mixture is formed of 70% by-product gypsum and 30% ash generated during the incineration of waste liquor and wood bark from the sulphite cellulose industry.

The essential substances for the invention are CaSO 4 * 2H 2 O in waste gypsum, 'excess' water in waste gypsum and CaO in sulphite ash. The proportion of water in the form of crystalline water is about 20%, so the unbound water in the mixture is about 20%. strength.

The inventions are characterized by a manufacturing process in which both components are mixed together as powders. The mixture is then compressed in a mold with a very strong compression pressure, e.g. 10 kN / cm2. Due to the high compression pressure, a reaction occurs which hardens the mixture at the end of the mesh. The main event in compression is that the excess water contained in the by-product gypsum reacts with the calcium oxide contained in the ash to form a hard body. The present invention has the advantage of contamination, but the raw material mixture according to the invention does not allow clay wafers to be produced at economically competitive prices. A pressure of 120 tons to produce a standard clay wafer and thus the equipment investment cost and energy requirement become unreasonably high. The so-called press type is best suited to the so-called eccentric press.

The main weaknesses of the current production method are the health effects of the products on humans and animals and the polluting effect of the products on the environment.

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The current coal tar pitch-based pieces of clay disc remain in nature for years, contaminating it - unless 9281 8 4 they are systematically collected there. However, collection activities are difficult to organize and are a cost-increasing measure, as the number of shots fired in Finland alone is approximately EUR 24 million. pcs / year. In addition, clay wafers made today are oil-dependent in terms of raw material base, and given the limited oil resources on earth, it may not make sense to use these raw material resources for products that can be made from other raw materials at significantly lower prices.

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With the method of manufacturing the gypsum board according to the invention, the above-mentioned drawbacks can be eliminated. To achieve this, the manufacturing method according to the invention is characterized by what is set forth in the characterizing part of claim 1.

The invention achieves several advantages over the method in use. The most important advantage is that the gypsum wafer made according to the invention eliminates the pollution problems of nature and health, which are currently detrimental to the Firearms species. In addition, the gypsum disc made according to the invention withstands the stresses caused by the casting device and the transport on the clay discs better than the conventionally manufactured clay discs. This makes it possible to re-throw the shot-25 discs as targets. The better strength properties are due to the fact that in the manufacturing method according to the invention no stresses are created in the discs which promote their breakage. Conventionally made clay discs shrink as they cool in the mold, creating these stresses.

In addition to the above, the economic benefit obtained when the oil-based product is replaced by a product according to the invention must be taken into account.

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In the following, the invention will be explained in detail by way of example. To make gypsum wafers, II is formed; 9281 8 5 a homogeneous mixture containing, for example, 63% process gypsum, 23% calcined gypsum and 14% iron or other heavy metal oxide of specific gravity.

5 Example of raw material analysis

Process gypsum CaSO 4 * 2H 2 O 72.5% H 2 O 25 P2Os total 0.6 10 P205 vl 0.3

Fe203 0.3 A1203 0.03

SrO 0.25

MgO 0.04 15 K20 0.03

Na20 0.1

SiO2 0.2 F 0.5

Calcined gypsum CaSO 4 * l / 2H 2 O 100% 20 Iron oxide Fe 2 O 3 96%

SiO2 2

MgO 0.3

CaO 0.3 Al 2 O 3 0.4 25 'The essential components of the mixture for the invention are process gypsum CaSO 4 * 2H 2 O, calcined gypsum CaSO 4 * 1 / 2H 2 O and iron oxide Fe 2 O 3.

30 Other substances do not have a direct effect on the strength of the product. They act only as fillers in the mixture, with the exception of the liquid added during the manufacture of the product, which, together with compression, causes the internal reaction of the ingredients. The presence of iron or other metal oxide in the mixture according to the invention is due not only to the reactivity of the oxide it contains to the other ingredients of the mixture, but also crucially that the high specific gravity 9292 8 6 can be used to adjust the weight of the gypsum wafer to the desired thickness. which is very important when adjusting other properties of the gypsum board, such as its fracture.

It is essential for the production method according to the invention that the finished, homogeneous mixture is metered into the mold and at the same time a suitable amount of liquid, e.g. HaO, is added to the mixture.

10 The mixture is compressed in a mold. Due to the compression and the liquid added to the mixture, the mixture hardens. Curing continues after removal from the mold and the product reaches its final strength within a reasonable time. The method does not require a high pressing pressure, so the most suitable pressing device is the so-called

15 hydraulic presses. According to the method, the finished test-shot wafers have been prepared by compressing the mixture with a force of 300 kN, which means n in relation to the area of the wafer.

2.7 kN / cm2 pressure. The main event in the process is that under the effect of compression, the excess water, together with the other substances in the mixture, react with each other to form a hard body. Curing continues until all excess water has been removed from the product. However, the foregoing is in no way intended to limit the invention to this example only, but many modifications are possible within the scope of the inventive idea defined by the following claims.

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Claims (3)

1. A method for the manufacture of single-use measuring objects for use in sports shooting or the equivalent of example p. Clay pigeons, characterized in that a material mixture containing process gypsum CaSO Fe 2 O 3 and a suitable amount of water-containing liquid, preferably water, and the components of which react red to each other, are dosed in a mold and where the thus obtained raw material is subjected to a low compression pressure, e.g. 3 N / cm1, solidifies the mixture. 2. A method according to claim 1, characterized in that, in the powdered material mixture containing gypsum of different crystal water content, an aqueous liquid, preferably water, is applied to the reaction of the components, and the solidification reaction proceeds until the excess liquid has evaporated. product. A method according to claim 1 or 2, characterized in that the mixture is most suitably pressed with a hydraulic press in a mold which corresponds to the shape of the final product.