Animal husbandry – Material for absorbing moisture from waste product
Reexamination Certificate
2000-11-22
2003-05-27
Jordan, Charles T. (Department: 3644)
Animal husbandry
Material for absorbing moisture from waste product
Reexamination Certificate
active
06568349
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains to a natural product litter composition and methods for use as a sorbent for liquids.
BACKGROUND
The use of litter as a sorbent for pet animal urine and other waste liquids has been known for years. Typically, the litter is placed into a container or in an area in which the pet has been trained to use for urinating and defecating. Many prior art litters have been derived from sand, clay, and other minimally sorbent materials. More recently the useful life and sorbency of these litters has been increased by addition of binders and other additives which cause a clump to form from litter soiled by urine and fecal liquids. See e.g., U.S. Pat. Nos. 5,216,980 and 5,176,107. Formation of soiled litter into a clump, in part, minimizes the spread of urine or fecal liquids thus minimizing contamination of the unsoiled litter surrounding the excreted waste liquids. Additionally, clumping reduces the tracking of the soiled litter out of the litter container.
More recently, natural products such as grains, cellulosic products such as sawdust, woodchips or plant hulls have been used as a litter. See eg, U.S. Pat. Nos. 4,206,718; 4,727,824; 4,883,021; 5,109,804; 5,152,250; 5,690,052; 6,014,947. These products were developed in an effort to enhance the sorbency of the litter as well as provide a biodegradable litter. Litters with higher sorbency can minimize odors, reduce the amount of litter required and minimize disposal problems of the wetted litter. Although highly sorbent litters have been prepared, many of them tend to swell excessively when contacted with liquids causing problems such as blockage of sewer or septic lines when flushed down a commode.
The present invention is directed to providing a highly sorbent natural product litter with low swelling and suitable clumping characteristics. The invention also provides methods for preparing and using natural product litters with high sorbency, low swelling and suitable clumping characteristics.
SUMMARY OF THE INVENTION
The present invention provides an improved natural product sorbent composition. The sorbent can be a mixture of 50% to 99% by weight ground grain and 1 to 50% by weight wood particles. The sorbent is biodegradable, scoopable and flushable. The ground grain is typically prepared from cereal grains. In one preferred embodiment, the cereal grains are wheat varieties including white wheat, spring wheat, winter wheat, durum, and combinations thereof. The wood particles are typically derived from trees with wood having good sorbency characteristics such as, for example, aspen, poplar, pine, birch, cedar, and combinations thereof. The wood particles typically sorb an amount of liquid based on weight equal to at least about 1.0 times and preferably at least about 2.0 times and more preferably at least about 3.0 times the weight of the sorbent. Preferably, the wood particles are sawdust or wood chips that are smaller than about 4 mm. A preferred composition is one in which the ground grain is hard red spring wheat and the wood particles are aspen. Upon contact with a liquid, the sorbent can sorb an amount of liquid based on weight equal to at least about 1.0 times and preferably at least about 1.5 times and more preferably at least about 2.0 times the weight of the sorbent.
The invention also provides a method for preparing a sorbent containing 1 to 50% by weight wood particles and 50% to 99% by weight ground grain. After selection of wood particles and ground grain, a litter mixture is prepared. In one embodiment, the litter mixture is pelletized. In another embodiment, the pellets are crumbled.
In another embodiment, the invention provides a method for producing a pelletized sorbent from ground grain. The ground grain pellet may contain additives including, for example, wood particles to improve sorbency, deodorants, agents to inhibit microbial growth, anti-dusting agents and animal attractants. In one embodiment, the pellets are crumbled.
The invention also provides a method for sorbing liquid using a sorbent containing ground grain and wood particles. Ground grain and wood particles are selected and mixed to produce a litter mixture. The mixture contains 50% to 99% by weight of a ground grain and 1 to 50% by weight of wood particles. The litter is situated such that a liquid to be sorbed can contact it. Upon contact with the liquid, the litter mixture preferably forms a clump and sorbs an amount of liquid based on weight equal to at least about 1.0 times and preferably at least about 1.5 times and more preferably at least about 2.0 times the weight of the litter mixture.
DETAILED DESCRIPTION
The present invention provides an improved natural product sorbent composition and methods for sorbing liquids. The sorbent composition can be a litter mixture of ground grain and wood particles. Preferably, the sorbent has low odor and is biodegradable. Upon contact with a liquid, the sorbent can form a low attrition clump that is easily separated from the surrounding unwetted sorbent. When the sorbent is disposed of down a commode, the clumps can break down. The sorbent typically has a low tendency to swell, thus reducing the likelihood of plugging a sewer or septic system upon disposal.
A ground grain of the invention can be prepared from, for example, cereal grains such as wheat, sorghum, barley, rice, oats, rye, triticale, millet, corn and other grains for which “cereal grain” is a generic term. The ground grain may be prepared from a single grain or combination of grains. The grains may be combined before or after the grinding process. Preferred cereal grains of the invention may be selected from the group of wheat varieties including white wheat, spring wheat, winter wheat, durum and the like. In one preferred embodiment, the ground grain is hard red spring wheat.
The ground grain is prepared by grinding whole raw grain. Prior to grinding, the whole raw grain can be put through a cleaning device to remove foreign materials including stones, rocks, metal, dirt, dust, weed seed and other nongrain material. Such cleaning devices are known in the art and include, for example, magnets, disk cleaning mills, sieve cleaning mills and similar devices. The grain may then optimally be subjected to disinfestation using an infestation destroyer. The order in which the grain is cleaned and disinfested is not important. Infestation destroyers are known in the art.
After the grain is cleaned and disinfested, it is subjected to a roller or a hammer mill to crush the whole grain into smaller particles. After the grain is crushed (ground) it moves into a sifter where large particles are separated by passing through a mesh sieve and returned to the roller or hammer mill until the proper particle size is achieved. Typically, the particle size is reduced such that at least 95% of the particles are less than 4 mm (pass through a 5 mesh screen). Preferably, at least 95% of the particles are between 4 mm and 125 &mgr;m (pass through a 5 mesh screen but not a 120 mesh screen).
Wood particles of the invention can be produced, for example, by grinding, milling, or cutting. The source of wood can be, for example, trees, timber, cellulose fibers, or wood by-products such as bark and wood shavings. A single type of wood or combination of wood types can be used.
Typically, the wood particles are sorbent materials that can sorb an amount of liquid in weight between about 0.5 times to about 5.0 times the weight of the wood particles. The wood particles typically can sorb an amount of liquid equal to at least 1 times and preferably 2 times and more preferably at least 3 times the weight of the wood particles. Sorption includes both adsorption and absorption of the liquid into or onto the wood particles. Suitable sorbent wood materials include, for example aspen, poplar, birch, pine, cedar, and the like.
The wood particles typically are obtained by grinding or milling. The wood particles may be derived from a pelletized or ground wood product. Sources of ground and pelletized aspen products include Green Pet Produ
Doeringg Alan
Hughes Mike
Johnson Jack
Golba Tara M
Jordan Charles T.
Pet Care Systems, Inc.
Welsh & Katz Ltd.
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