NZ233244A

NZ233244A - Granulated animal litter having a water content of 40 to 70% by weight

Info

Publication number: NZ233244A
Application number: NZ233244A
Authority: NZ
Inventors: Mirjam Krahenbuhl
Original assignee: Organ Faser Technology Co
Priority date: 1989-04-10
Filing date: 1990-04-06
Publication date: 1992-04-28
Also published as: EP0392444B1; AU5298890A; AU636601B2; NO900898L; CH680894A5; ATE101957T1; FI900966A0; NO900898D0; EP0392444A1; DK0392444T3; DE3911678A1; DD299024A5; CA2014292A1; DE8906631U1; DE59004717D1

Abstract

The invention relates to a new process for producing animal litter, using fillers and additives which react with water. These fillers are obtained from a fraction from household, industrial and similar waste and/or from paper sludge. The fraction obtained from the waste is pulverised and mixed with the additives, the mixed product is adjusted to a given moisture content and then granulated, and the resulting granulate grains with a specified particle size are separated out. The animal litter produced according to the invention ensures a high deodorising level, high absorbency and has low bulk weight. <IMAGE>

Description

233244 Priority Date(s): AQ.....Ur....

Specification Filed: ...Cfi....Ur.~S|0 Class: (3).AO.iK.i./.Oi..^./ .33-2^. .Cfl. .Q .1 .J2D./.D. [4. . ..^.^0^5.40.0 Puojicaticrn Dste: .]?j92 PX). Jour«Q{, Ho: Patents Form No. 5 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION ANIMAL LITTER AND A METHOD FOR ITS MANUFACTURE WE, ORGAN-FASER TECHNOLOGY COMPANY N.V. organised under the laws of the Netherlands Antilles of de Ruyterkade 62, Curacao, NETHERLANDS ANTILLES hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: (followed by page la) 233244 0 This invention relates to a method for the manufacture of animal litter and to litter made by the method. Animal litter made by the method is in a solid, granular form and exhibits a high degree of odour retention and has high absorbing power and low apparent density.

O 1 o BACKGROUND Of THE INVCNTIOM AMD PRIOR The known materials for the manufacture of Litter for animals are essentially natural products of mineral ( . origin such as pumice stone, bentonite, clay minerals, for example sepiolite, diatomite, or of organic origin 15 such as wood flour, sawdust and peat which, because of their porous structure, have the property of absorbing liquids in their pores.

For years granulated drying and/or absorbing agents have been used for keeping household pets clean, 20 especially in densely populated urban and suburban areas. Such products are mostly bought and used in large quantities by owners of small animals, in particular cats. w/ Nowadays a variety of products with very different ; 25 properties is marketed under the name "cat litter". The majority of these products, as already mentioned above, are manufactured on a mineral basis.

An animal litter of this kind is known, for example, from OE-PS 31 21 403, which is made using a porous 30 inorganic material with a pore structure. The porous material used here consists of calcium silicate granulate and/or calcium silicate powder which has a pH-va lue between about 5.8 and 6.2.

The known animal litter made from calcium silicate 35 granulate having a pore radius of less than 500 nm retains its shape and consistency and is bactericidal. 4 — N.2. PA1 a 14 FEB 1992 ?3 3 2 4 4 o However, after prolonged use of such materials an unfavourable smell develops so that the animal litter often has to be changed even though the absorbing power of the material is by no means exhausted.

The afore-mentioned animal litter products with their different characteristics do, however, have further disadvantages. Their high specific gravity causes great practical problems in the supply and transportation of the packaged product. Some of the animal litter preparations consist of sharp-edged - in particular broken - stones, which leads pawed animals to avoid the sharp granules.

In relation to the weight of the product the take-up of liquid in many known products is very small. After 15 reaching their absorptive capacity these products tend to swell and thus form clumps. This effect is still more marked in the case of diatomite, which becomes very sticky, greasy and even pasty. These disadvantageous properties necessarily lead to difficulties in handling 20 such products. Because of these product characteristics the litter must also be changed often and as a result more is used.

In the manufacture of these animal litter materials a large proportion of fine dust is formed as a result of 25 the way they are crushed, and by abrasion in the drums or other containers during storage, transport and handling between the manufacturer and consumer. Handling the open container in the pet owner's home raises a great deal of dust, especially when changing the litter in the boxes. 30 In addition this high proportion of fine dust is bad for the animals, since they inhale the dust when scratching in such products.

After use, such water-insoluble stone and/or mineral animal litter products can only be disposed of as or with 35 domestic waste. This causes the waste disposal plants to be burdened with a not insignificant amount of such waste 2 2 3 3 2 4' products. In Switzerland and in the Federal Republic of Germany, for example, about 40,000 tons and 500,000 tons respectively of waste consisting of this kind of product accumulates each year. This shows that the market for 5 such (albeit improved) animal litter products is very large, especially in densely populated urban and suburban areas.

An object of the invention is to provide a method for the manufacture of an animal litter which overcomes the disadvantages of the prior art and ensures a high degree of odour retention, has high absorbing power and low apparent density. The new animal litter is intended to fulfil the optimal requirements for man and animal with regard to quality and economy.

Accordingly, this invention provides a method for the manufacture of animal litter that comprises granules that have a stable, porous surface of substantially bound additional material and a soft, absorbent core of filler materials and substantially unbound additional materials, the method comprising: forming a granulate using additional materials, that react with liquid, and filler materials by pulverizing the filler materials and mixing them with the additional materials; adjusting the pulverized mixture to a moisture content of 40 to 70% by weight by adding water; forming the mixture into substantially spherical granules and drying the resulting granules; and separating those granules that have a predetermined particle size to provide the animal litter.

The method differs from known methods in that a wet process is used. 3 233244 3 5 The spherical animal litter granulate according to the invention has the following specification: The granulate has a particle size in the range of 1 to 10 mm diameter and is spherical. In the finished animal litter product spheres of all sizes are advantageously mixed together. In this product, however, the preferred 5 particle size range is from 2 to 5 mm diameter. The granulate also has, according to the invention, an apparent density in the range of 200 to 700 kg/m3, /"~x advantageously in the range of 300 to 500 kg/m3. The colour of the animal litter product according to the 10 invention is greyish to brownish, and can to a large extent be adapted to the desires of the consumer.

For the first time a new animal litter can thus be provided which consists of a granulate having an organic 30 fibre basis, prepared from waste materials and additional materials. For this a precrushed fibre and/or granulate fraction obtained from domestic, industrial and similar waste could be used, which can be manufactured according to DE-PS 31 05 597 (copy available upon request).

By reutilising slurry from the paper and pulp industry and/or from wet fibre plants a granulate can be produced in which all the substances (solid materials and liquids) can be recycled or utilised. By the use of the paper slurry, the burden on the environment can be further reduced, as hitherto this waste would have had to be dumped and destroyed.

(^) The animal litter according to the invention is particularly useful as litter for cats.

Compared with known animal litter products the 15 product manufactured according to the invention has the following advantages. The new litter according to the invention is very easy to handle in comparison to known litter products because it has a low apparent density. In addition, the product according to the invention does 20 not have a fine dust fraction and is abrasion-free 4 N.Z. PATENT OFFICE according to the abrasion classification (modified SHELL-Index). Owing to its high absorbing power the litter according to the invention does not need to be changed frequently and thereby reduces use of large amounts so that a longer life or period of use are ensured. The product according to the invention can advantageously be disposed of down the drains or by domestic compost preparation.

To sum up, the animal litter according to the invention has, compared with the known animal litter products, the great advantage that with the superior absorption or adsorption capacity (high absorbing power) of the granules according to the invention having an organic fibre basis, prepared from waste and used materials with the addition of diverse materials, such as lime, calcium hydroxide, gypsum and similar materials and a certain amount of residual moisture, it not only, as already mentioned, retains its shape and consistency but is also odour-retaining, bactericidal and easy to dispose o f .

The invention will now be described in more detail with reference to the accompanying drawing, in which Fig. 1 shows a flow diagram of the manufacture according to the invention of an animal litter according to an embodiment of the invention.

DETAILED DE3CRIPTI0N OF A P R C f E K R C D EMBODIMENT OF THE INVCNTIfrN— By way of example, the manufacture according to the invention of the now animal litter having a precomminuted organic fibre basis, prepared from waste materials was carried out as follows, with reference to Fig. 1.

The following starting materials were used: approx. 60 X/wt. organic fibres, prepared from waste and used materials (according to OE-PS 31 05 597), — N./_. PAiENT OFFICE • £l f 4 FEB 1992 2332 approx. 32 %/wt. Lime or calcium hydroxide or gypsum, approx. 8 Z/wt. water.

The organic fibres, prepared from mixed domestic, industrial and other such waste which can be manufactured according to DE-PS 31 05 597, are stored in a storage bin 1. The pr.e-comminuted organic waste mater i a Ls are withdrawn in measured amounts from this bin 1 and delivered to a pulverizer 3.

Pulverizer 3 then pulverises these materials to dust and the powder made in this way is transported pneumatically (not shown) to a metering bin 4.

The metering bin 4 then conveys the powder, metered by weight, to a mixer 6. The additional materials (lime, calcium hydroxide, gypsum or similar materials) are then metered from a storage bin 2 according to a special formula and sequence and are likewise supplied to the mixer 6.

Water metered from a device 5 is then conveyed to the mixer 6. The mixer 6 can be a-known cyclic batch mi xer, having the function of mixing the components according to a special program. A conveyor (not shown) conveys the finished mixture to a mixture metering device 7. This mixture metering device has the following functi ons : a) Storing the mixture and b) metering the mixture.

A mechanical conveyor (not shown) then transports the mixture metered from the mixture metering device 7 to a granulating device 3. The function of the granulating device 8, which in an embodiment of the invention comprises a rotating drum, is to spheroidise the mixed material. The speed, inclination and residence time of the mixture are important for determining its shape. The granulating device can alternatively comprise a plate or a worm .

J""*" ;OFFICE ;6 14 FEB 1992 ;2 3 3 2 4 4 ;I } ;Vj ;The granules obtained are conveyed from the granulating device directly to a pre- ;screening device 9. This pre-screening device 9 ;separates the oversized granules from those with the ;5 maximum final size (10 mm diameter). A conveyor (not shown) transports the oversize pieces back to the mixture metering device 7. ;The granules -a-*—li t tar are then conveyed to a secondary treatment device 10 by a conveyor (not shown). 10 The function of the secondary treatment device (poaition 10 is to dust the granules of litter with a mineral powder. A conveyor (not shown) then transports the dusted granules to a drier 11. This drier 11 comprises a rotating drum with a heating device (not 15 shown) arranged before it. The function of the drier 11 is to dry the granules at a specific temperature, while continually moving and rolling them, from about 4 G to 70% water content to a maximum water content of 8 %/wt. without the granules' pi-ococi' being damaged or 20 deformed. At the end of this drying phase hard granules are formed which are conveyed directly to a separating housing 12.

The separating housing (poaition 12 comprises a settling chamber and a granule discharge outlet and 25 separates the granules from the steam-air mixture that has been formed during drying.

The granules are then taken by a conveyor (not shown) from the outlet of the separating housing 12 and transported to a fractionating device 13. The 30 fractionating device 13 separates the granules into two grain sizes. In the method according to the invention the fine grain material, advantageously less than 1 mm diameter, is supplied to the mixer 6 for recycling by a conveyor (not shown).

The product (granulate) obtained is supplied to a cooling/dust-removing device 14 likewise by a J'-J .J.

PATENT OFFICE 14 FEB 1992 233 2 4 transporting unit (not shown) .

The function of the cooling/dust removing .device 14, in which there are built-in fans, is to cool the product, which is still hot, to room temperature and simultaneously remove the dust. The cooled product is then conveyed directly to a deodorizing device 15. The deodorizing device 15 comprises a swinging container with a pneumatic injection device and its function is to spray the product uniformly with the preset fragrance note.

A transporter (not shown) conveys the finished animal litter product to a portion dispensing device 16.

This dispensing device 16 divides the product stream into portions of the predetermined commercial size and passes these directly to a packaging device 17. ihe packaging device 17 takes the portions and fills them into bags, which are then sealed immediately and stacked in a container.

The average materia litter granules obtained as follows: apparen t densi ty moisture/liquid take-up capaci ty particle size co lour water content loss at red heat Abrasion (mod. SHELL-Index) The products manufactured in this way according to the method of the invention and having an organic fibre basis, prepared from waste and used materials, can be used with advantage as animal litter, in particular as litter for cats. As shown above the product according to J 't i.Z.. PATENT OFFICE I 14 FEB 1992 l parameter values of the animal according to the invention were approx. 400kg/m3 between 90 and 120 g water/ 100 g litter in the range of 2 to 5 mm light grey 7.7% 56.1% 1.8 0 / 0 0 at 6 kg/cm2 ^ . • . 233244 the invention is superior to known commercial products in respect of apparent density, absorption of moisture/liquid and abrasive behaviour. Since the new product according to the invention is also superior to 5 known commercial products in respect of odour-retaining power and in the other ways mentioned above it is suitable as a superior animal litter, in particular as litter for cats. o < ( 1 I t ? J < I J t o u 233;

Claims

WHAT WE CLAIM IS:

1. A method for the manufacture of animal litter that comprises granules that have a soft, absorbent core of filler materials and substantially unbound additional materials and a stable, porous surface of substantially bound additional material, the method comprising: forming a granulate by pulverising filler materials that include a fibre fraction obtained from domestic, industrial and similar waste, and mixing them with additional materials that react with liquid; adjusting the pulverized mixture to a moisture content of 40 to 70% by weight by adding water; forming the mixture into substantially spherical granules and drying the resulting granules; and separating those granules that have a predetermined particle size to provide the animal litter.

2. A method according to claim 1 in which the substantially spherical granules are dusted with minerals before being dried and after drying the granules are cooled and treated to remove dust.

3. A method according to claim 2 in which the minerals used for dusting also act as a deodorant.

4. A method according to any one of claims 1 to 3 in which the granules are formed and dried simultaneously in a rotating drum.

5. A method according to any one of claims 1 to 4 in which the shaped and dried granules have a maximum water content of 8% by weight. : - •. ice 14 FEB 1992 2332 4 <i -l-i-

6. A method according to any one of claims 1 to 5 in which the granules remaining after the separation are returned to the mixture.

7. A method according to any one of claims 1 to 6 in which the additional materials used are selected from lime, calcium hydroxide, and gypsum.

8. A method according to claim 7 in which the filler materials comprise paper slurry.

9. A method according to claim 7 in which the filler materials comprise paper slurry and organic fibres and the initial moisture content is set by the ratio of paper slurry and organic fibres.

10. A method according to any one of claims 1 to 9 in which granules that have a particle size in the range of 1 to 10mm are separated to provide the animal litter.

11. A method according to claim 10 in which granules having a particle size of 2 to 5mm are separated.

12. A method according to claim 1 and substantially as described in this specification with reference to the examples.

13. An animal litter produced by a method according to any one of claims 1 to 12.

14. An animal litter according to claim 13 which consists of: a) 55 to 65 wt% of organic fibres prepared from waste materials; 233241 12 b) 30 to 34 wt% of additional materials; and c) 6 to 10 wt% water.

15. An animal litter according to claim 14 which consists of about 60 wt% of organic fibres prepared from waste materials; about 32 wt% of additional materials; and about 8 wt% of water.

16. An animal litter according to claim 14 or claim 15 in which the additional materials are selected from lime, calcium hydroxide, and gypsum.

17. An animal litter according to any one of claims 13 to 16 in which the granules have an apparent density in the range of 200 to 700 kg/m and a moisture/liquid take-up capacity of between 90 and 120 g water/100 g litter.

18. An animal litter according to claim 17 in which 3 the granules have an apparent density of 300 to 500 kg/m .

19. An animal litter according to any one of claims 13 to 18 in which the granules have a particle size of 1 to 10mm.

20. An animal litter according to claim 19 in which the granules have a particle size of 2 to 5mm. ORGAN-FASER TECHNOLOGY COMPANY N. V. BALDWIN, SON & CAREY