CA1317828C - Non-absorbent litter for use with absorbent pad - Google Patents
Non-absorbent litter for use with absorbent padInfo
- Publication number
- CA1317828C CA1317828C CA000605752A CA605752A CA1317828C CA 1317828 C CA1317828 C CA 1317828C CA 000605752 A CA000605752 A CA 000605752A CA 605752 A CA605752 A CA 605752A CA 1317828 C CA1317828 C CA 1317828C
- Authority
- CA
- Canada
- Prior art keywords
- particles
- urine
- sorbtive
- desiccant member
- absorbent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Classifications
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01K—ANIMAL HUSBANDRY; CARE OF BIRDS, FISHES, INSECTS; FISHING; REARING OR BREEDING ANIMALS, NOT OTHERWISE PROVIDED FOR; NEW BREEDS OF ANIMALS
- A01K1/00—Housing animals; Equipment therefor
- A01K1/01—Removal of dung or urine, e.g. from stables
- A01K1/0107—Cat trays; Dog urinals; Toilets for pets
Abstract
ABSTRACT OF THE INVENTION
The invention relates to the prevention of the odor caused by the action of bacteria on cat urine in a cat litter box. The cat litter box has a base and walls and is provided with a sorbtive-desiccant member for the collection of animal urine. Litter is in direct moisture transfer contact with the sorbtive-desiccant member. The odor prevention process includes the steps of transferringcat urine directly from granular particles, to the sorbtive-desiccant member, sorb-ing the urine in a sorbtive-desiccant member having high surface area and high urine sorbency, dispersing the urine quickly in said sorbtive-desiccant member, and evaporating said urine from said high surface area sorbtive-desiccant memberthrough the granular particles. The sorbtive-desiccant member maintains the urine in a medium which subjects the bacteria in the urine to the effects of drying. The granular particles are non-absorbent particles having sufficiently large diameter to provide sufficient interparticle spacing to permit free flow of urine from the particles to the sorbtive-desiccant member and the free flow of mois-ture from said sorbtive-desiccant member to the air. The base of the litter box prevents urine from leaving one side of said sorbtive-desiccant member. Thereby the bacteria, which are capable of breaking down cat urine, die or become dor-mant and thus prevent significant odor formation.
The invention relates to the prevention of the odor caused by the action of bacteria on cat urine in a cat litter box. The cat litter box has a base and walls and is provided with a sorbtive-desiccant member for the collection of animal urine. Litter is in direct moisture transfer contact with the sorbtive-desiccant member. The odor prevention process includes the steps of transferringcat urine directly from granular particles, to the sorbtive-desiccant member, sorb-ing the urine in a sorbtive-desiccant member having high surface area and high urine sorbency, dispersing the urine quickly in said sorbtive-desiccant member, and evaporating said urine from said high surface area sorbtive-desiccant memberthrough the granular particles. The sorbtive-desiccant member maintains the urine in a medium which subjects the bacteria in the urine to the effects of drying. The granular particles are non-absorbent particles having sufficiently large diameter to provide sufficient interparticle spacing to permit free flow of urine from the particles to the sorbtive-desiccant member and the free flow of mois-ture from said sorbtive-desiccant member to the air. The base of the litter box prevents urine from leaving one side of said sorbtive-desiccant member. Thereby the bacteria, which are capable of breaking down cat urine, die or become dor-mant and thus prevent significant odor formation.
Description
~ 3~ 7~2g NON-ABSORBENT Lll~R FOR llSE WITH AE~SORBI~T PAD
BACKGROUND OF TH~: INVENTION
Field of the Inventlon Thls invention relates to a specific non-absorbent litter for use In combina-tion with an a~sorbent medium for odor prevention in animal litter units. In partlcular the litter can be a mineral particle, such as coar~e sand, and the ab-sorbent pad can be a disposable, sorbent/dessicant pad~liner system.
Brlef Descrlption of the Prior Art Many domestic animals frequently use litter boxes for the elimination of body wastes. The boxes are usually filled wlth various kinds of granular materials such as sand, cat litter and the like, and must be periodically emptied and cleaned, which are somewhat objectionable tasks, since the absorbent granular ma~erial must be replaced and the boxes cleaned each time~
Cats, being the most frequent users of litter boxes, present a further problem in that the urine of the feline contains the highest content of urea which, when allowed eo stand for any length of time In any sorbent material, releases an am monia odor. This odor is one of the more obJectlonable factors in the ownership of a cat.
In order to eliminate the odor caused by cat urine, the lltter box must be changed frequently, necessitating the expensive, laborious and unpleasant chore.Summary of the Invention In accordance with the instant invention the foregoing prob~ems are overcome and an easy to use~ odorless, disposable sorbent pad system is provided. It has now been found that the ei ficacy of the dlsposable sorbent system can be op-timized if the absorbence of urlne in the lltter is mlnimlzed and eYaporation from the system is maximlzed~ Non-absorbent mlneral particles allow for the rapid entrance of the cat urlne Into the sorbent pad. The sorbent pad, can be constructed from high wicking capability materials. The formatlon of the odor associated with cat litter boxes is prevented by drylng, thus Inhlbltlng the bac-terial action on cat urine. The cat urine is transferred directly from overlylnglitter particles, through a cat claw resistant screen into a sorbtlve-deslccant member of fibers and having high surface area and high urine sorbency. The urine disperses quickly from flber to fiber in the sorbtive-desiccant member.
The moisture impermeable sheet preven~s urine from leaving the side of the sorbtive-desiccant member opposite the screen. The screen and the fibers of the sorbtive-desiccant member provlde for transport of moisture, alding the drying process of the urine, thus Inhibiting the growth and bacterlal action of bacteria.
13~ 28 Consequently, the bacteria die or become dormant thereby preventing slgniflcant odor form ation.
BRIEF DESCRIPTION OF THE DRAWINGS
The advantages and objects of the invention will become apparent and the Invention will be more fully understood from the following specificatlon, par-tlcularly when read In conJunction with the drawings, whereln:
FIGURE I is a top perspectlve of the assembled unit In accordance with the present Invention;
FIGURE 2 is an exploded fragmentary view of the sorbent pad of the instant invention;
FIGURE 3 is a graph which compares evaporation rate for several materlal and plots time versus quantity of water evaporated and retalned.
L~lr~2~
DETAILEV DEscRlpTloN OF T~IE INVENTION
. _ . _ . . . . . . ...
In order to provlde a clear undelstanding of the Ins~ant in~ent on, the various aspects of the InventIon are here~na'ter descr bed In d tall.
~ e sorbent pad structure of t:he instant inven-tion can include a pro-tective screening and a moisture impermeable liner. The protective screening that is fully disclosed in U.S. Patent 4,640,225, issued Febru-ary 3, 1987, is suited for use with the present invention. The screen must be capable of withstanding the clawing action of an animal such as a cat, thus protecting the sorbent pad and the moisture impermeable liner.
the holes in the screen are sized small enough to prevent the animal s claws from reaching the sorbent pad, while numerous and large enough to allow for air passage and rapid evaporation of liquids. The sorbent pad, constructed from high wicking capabi1ity materia]s, is positioned between the screen and the moisture impermeable material. Ille screen is sealed to moisture impermeable material along at least a substantial por-tion of their peripheral edges. The screen is a flexible member formed of strands -bonded at their intersections and is formed of a material which is sub-stantially inert to urine.
The formatlon of the odor associated with ca~ Iitter boxes Is ?revented byInhiblting the bacterlal actlon on cat urine. A sorbent pad structure is posi-tioned between a protectIve screening, capable of wlthstanding the clawing actlon of a cat, and a moisture impermeable liner. The cat urine is transferred directly from overlylng litter partlcles, through a cat claw reslstant screen into a sorbtlve-desiccant member of flbers and having hlgh surface area and high urine sorbency. The urlne disperses quickly from fiber to flber In the sorbtive-desiccant member. The moisture Impermeable sheet prevents urine from Ieaving the side of the sorbtive-desiccant member opposite the screen. The screen and the fibers of the sorbtive-desiccant member provide for aeratlon, thus inhiblting the growth and bacterial actlon of bacterla as well as ald the evaporation of the urlne from the sorbtive-desiccant member. Consequently, the bacteria die or become dormant, thereby preventIng slgnlflcant odor formatlon.
Cat urlne is normally sterlle, that is, free of bacterla which acts on the urine and produces the odor assoclated wIth cat urlne. Nevertheless, It has been found that If steps are taken to inhlbit the growth of, or cause the death of bacteria, odor formatlon can be prevented. It Is presumed that the bacteria present in the fecal excreta, or present in the lltter or alr borne bacteria ~3~782~
comes Into contact with the urlne, thereby producing an odor problem.
In accordance wlth the present invention steps are taken to prevent odor by killing the bacteria or Inhibltlng their growth, without havlng to resort to theuse of bacterlcldes.
Of all the varlous factors that Influence the growth of microorganlsms, water may be considered to be the most Important. Indeed, water may really be con-sidered a nutrlent since it forms ~he bulk of the cellular substance. Compared to higher organlsms, whlch regulate thelr water content to some extent, microor-ganisms are dependent upon the amount of water In the environment. For growth and multlplicatlon bacterla requlre hlgh concentrations of water in theirimmediate environment. In splte of thelr seemingly solld character and dry ap-pearance, agar media and other solid foods used for the cultivatlon of bacterla require hlgh concentrations of water as part of thelr composltion. When or-ganisms are grown on surfaces such as an agar plaee, hlgh humidlty can provide condltlons favorable to the development of mlcroorganlsms. Water acts as a sol-vent, and most metabolic activitles are conducted wlthln an aqueous envlronment in the cell. Water also serves as a catalyst by aiding or actually enterlng intomany enzymatic reactions. Turgidlty of the cell is dependent upon the presence of water. In turn, turgidity is affected by the surface tension (osmotlc tenslon) of the medium in which the organisms are suspended. It probably would be cor-rect to consider all bacteria as aquatic organisms.
Water is necessary for the existence and vlability of mlcro-organlsms. The effects of desiccation on the vlabllity of mlcroorganlsms provldes a good example of the Importance of water. Slow deslccatlon In the presence of alr Is most detrimental. Although many specles of mlcroorganlsms can survlve complete drying or desiccatlon for long periods, they do not grow under such condltions.
In a state of complete deslccation the metabolic processes must stop almost completely since these depend largely on osmosis, dlffuslon, lonlzatlon and the colloldal state, all of whlch are dependent In turn on hydratlon.
GRANULAR MATERIAL
Mlneral partlcles such as small pebbles, rocks, stones gravel, coarse sand and the llke previously unsuitable as a cat lltter material because of the lack of ab-sorbency or their abillty to hold urine that pools In the bottom of the lltter box can now be used as a more effectlve cat lltter box flller when used wlth ab-sorbent pads. Because of thelr Inherent ablllty to allow urine to rapidly draln ~L317~28 into the absorbent pad without impeding the flow or spread of the urine through out the pad and allowing for a more rapid evaporation of the urine back through the particles and through out the absorbent pad due to the more numerous air spaces between these largeT partlcles. Very fine pa}tlcle such as fine sand or soil, will not act a a good cat box filler because of the flow of urine into thepad is impeded by the numerous particles. The transmission of the wa~er vapor through these particles is also Impeded.
The granular materlal as employed In the instant inventlon is utilized to satisfy the digglng Instinct of the animal and therefore need not provide absorp-tive qualities. Conseque~ y, 3inexpensive non-absorbent materials, including naturally occurring materials such as coarse sand and gravel, or synthetic materials such as glass and polymer beads, can be used in accordance with in-dividual preferences. Unlike the commonly employed systems In which the granular material must be used In quantlty to provide the required absorptive qualltles and digging qualities, minimal ~uantlties of the granular material can be used, as described herein. The absorptlon quality of the layer 24 can provide the ~otal or the predominant deslccation effect.
Hence, proper sized non~ sorbent niineral particle cat box flller serves the functlon of actin~ as;
1. An attractive digging medlum for cats ~. Allows cat urlne to fall rapldly over the partlcles into the absorbent pad.
3. Allows cat urine to migrate rapldly withln the pad since ~t Is not drawn up and trapped on absorbent partlcles llnlng the interface of the cat litter-rip proof layer.
4. Rapid migration of urine within the pad allows for more rapld evaporation out of the pad.
5. Water vapor can escape up through the pad, through the mineral litter par-ticles.
6. In addition to e~aporation from the absorbent pad, the mlneral particles wet by the vold will dry and hence the effective surface area producing evaporatlon is greater for the combination of the pad with wetable non-absorbent particles than with the absorbent partlcles and absorbent pad.
7. Mineral particles wet by the previous vold wlll become dry due to both dralnage and evaporation ancl thus the suriace area of non-absorbent partlcles avallable for alding in evaporatlon is maintained at a maximum value. (By way Page S
~ 3~7~28 of contrast, absorbent litter particles stay wet and lose thelr ability to function as an absorbent and an evaporation surface.) 8. The heavy mlneral particles scatter out of the litter box less than light weight clays and similar absorbent litters.
9. The washed mineral particles contain less dust than clay and is not friable therefor creates no dust of its own.
The litter material is commonly in granular form and must be in moisture transfer contact with the underlying sorbent material so that the urine can be drawn from the litter material into the sorptive layers. The use oi a surfactanton the screen m aterial can enhance the moisture transfer capability of the screen and is essential in combination with hydrophobic or low hydrophilicity screen materials. The particle size distribution can range from a few mil-llme~ers to several centimeters. Flne sand having a particle size at the lower end of sands, that is at the 200 mesh (0.074 mm.) slze pac~ so densely as to limie or restrict liquid and air flow between the particles. At the upper end ofthe particle size the sand or gravel material can be reJected by the cats and fail to enhance the distributlon of the liquid across the absorbent pad, as evident from the test and the graph of Figure 3.
While reference has been made in partlcular to sand, it should be understood that non-absorbent materlals, in partlcular other inorganic mlnerals, in generalwill provide similar results.
Particularly suited to the instant invention is a coarse sand referred to as fine gravel commonly found in central New Jersey. These gravels and sands were deposited during the formation of the early coastal plaln The sands and gravels consist mostly of quartz or silica. The available particles are found in a wide range of particle slzes and must be sieved to obtain the deslred particle size distribution. The non-absorbent particles must be sufflciently free of friable materlals, such as clay, In order to avold the fllling of the Interstlces. The particles can be as small as one millimeter in diameter and as large às three centimeters. The preferred range, however, Is between two millimeters and about one centimeter. It should be understood that the partlcles typically are not round, but rather, most typicall~ are oval or irregular in shape and the dlameter referred to Is the average diameter of the particle. The particles are washed to get rld of the small dust particles and then air or oven dried prior to use as a non-absorbent litter.
~3~7~2~
Eor acs~hetic effect, the particles can bc dyed to a particular color. Mor-dant dyes can be used where the partlcles are sillca. Ttle particles can bc coated to moderate the hydro-pl1obicity or hydropllllicity of the surface of theparticles. The use of waxes, sillcons, and the like can be used In this regard.
Although glass beads, Teflon * (T.M. ) coated particles, polypropylene or polyethylene, synthetic and natural resins can serve as the same function as non-absorbent coarse sand or fine gravel, a large number of cats will reject the use of these products as a cat box filler. Very large particles such as large pebbles or gravel, rocks, etc., tend to be very heavy and easlly packed ~hen used as a catbox filler and also can be rejected by cats. Digglng Is difficult with large heavy particles and can also lead to rejection by cats. The coarse sand, on the other harld, mlrnics the appearance ol the comrnercially available absorbent c13v litters, is readily used by the cat for digging and as a waste matter repositoryand has the further advantage of resisting scatterlng and tracking by the cat.
In addition, the non-absorbent granules are non frlable and dustlng is consequentl-nega t ed. -ABSORBENl` UN-11`
The absorp~ive elements can be an~ material such as paper, tlssue, pulp starch and related polymers, etc. ~4hich can disperse the llquid quickly, thus providing a large surface area for evaporation of moisture. In order to rnaintain a moisture free environl1lent~ it is necessar~ to evaporate from a to 20 ml. o~
liquid each time the s-s;em is used by the cat.
Examples of sorben~ materials are those manufactured by Do~ Chemical and marketed under U.S. Patent 4,117,18~. This product is commonly identified as c~
super absorbent and sold by Dow Chemical Company under the desi~nation D~1AI. 35 !~.
( T . M . ) Alternativcly, the super sorbent can be a material such as the National Starch and Chemical Corporation procluct sold under the registered trademark PER,~ASORB. l he National Starch product is a h~drophillc polymer which has the abillty to absorb and hold urlne. There is a slgnlficant reduction in urine odor and pH level In the presence of PERMASORB.
Another eY; mple of an absorbent is the material sold under the trademark WATER-LOCK by Grain Processing Corp.
In contrast to the ultra-h~gh absorbency materlals, ground paper pulp absorp-~3~7~2~
tlve material has becn found to provide a combination of hlgh absorbency, highsurface area and low cost. The large surface area provides for rapid urine evaporatlon and consequently is extremely effeceive in odor prevention.
Toxic chemicals or blologlcally active ingredlents are not only unnecessary but preferably are avolded. U.S. patent 4,494,482 assigned to Proctor and Gamble relies on the use of 5000 to 30,000 ppm of a halogenated aromatic hydrocarbon bacteriostat in an sorbent pad to effectively control odor develop-ment. It has been found that If the sorbent materlal has the abillty to absorb the urine, distribute the urine rapidly throughout its mass, and evaporate the urine faster than the bacteria can act on the urine, then the additives are not only unnecessary but undesirable.
Bacteria froln the feces cannot grow in the absorptive layer because they are dried out and die or become dormant. It is the bacteria which is capable of breaking down the urine which cause the strong volatlle odor commonly as-sociated with cat lltter boxes, the dry environment of the sorbent material ef-fectively prevents odor. The high absorption capacity of the super absorbent polymers, such as available from Dow Chemical, do not provide an advantage over a pulp flber, due to the hlgh rate of evaporation of urine from the flberous materlal. As previously stated, the instant inventlon requlres substan-tially less granular material for each use and requlres fewer changes, saving fur-ther on granular use. In the prior art ~ype of lltter box, the lltter consumption is greater than in accordance with the present inventlon.
The amount of litter which is used can be decreased wlth time In order to permit the cat to become accustomed to the low litter level. In some cases, cats can be tralned to the pads without lltter. Whereas, in conventional litter boxes, two to three inches of litter are required, in accordance w!th the present Invention less than one Inch of lltter, and preferably no more than about one half inch, provides the deslred rssults, as evldent from the chart which appearshereinafter.
It has been found thst the use of over an inch of an absorbent lltter can actually retard the moisture evaporation, apparently due to the litter serving as a moisture barrier between the sorbent unit and the atmosphere~ In actual use it has been found that the clawlng and scratching of the cats tends to expose reglons of the screen or at least greatly reduce the amount of lltter covering csrtaln regions of the screen. Although the ideal system would be free of litter ~ 3~2~
the cats tend to reject a litter container which is totally lltter free. The useof a non-absorbent litter which does not pack, or conversely, which permits the sorbent unit to "breath" minlmizes the adverse effects of standard litters.
Figure I illustrates the assembled unit 10 of the instant invention. The granular material 20 Is placed on top of the sorbent unit 12 to provide the snimal with the necessary scratching materials, if so required~ The granular materlal would not be requlred If the unit was being used for a dog or other animal which did not have the scratching instinct.
The sorbent unit can be used with standard litter boxes and can be combined with the adhesive securing means, elastici~ed securing means or any other method disclosed in copending applications.
Fi~ure 2 shows, in exploded form, a cross-section of the layers which form the sorbent unit 12. The outer layer 22 which is a thin plastic sheet of a material such as polypropylene or polyethylene prevents waste from making con-tact with the box and can double as a bag when disposing of the soiled litter.
A protective layer 26, which can be used, If desired, is made from a durable, non-woven tlssue substance. If a binder Is used for either the fabric of the tissue layer or o~her layer, it must be of a non-water soluble material.
The protective screen 28 is of a flexible7 durable substance which prevents the animal from scratching through to the bottom layers. The granular material ~0 isplaced on top of the sorbent unit as previously described herein.
Urine evaporation tests were conducted for the purpose oî comparing the evaporation rates of a variety of materials. in one instance the quantity of water was contained in a bowl having an eight inch diameter. In all instances 9 milliliters of liquid were tested since this represents the average amount of urine deposited on a litter pad by a cat each tlme It uses a pad. Qulte obviously a young kitten will ~ass less liquid than a large adult cat. Statistically it has been determ~ned that cats will void once every four hours and the quantity of liquid will be about 9 milliliters. In the event that the rate of evaporation ofthe urine is slower than the rate of deposit of urlne in the pad, the pad will never reach a dry state and the odor associated with bacterial action on urine can not be prevented. It should be noted that a four hour time limit is beyond the maximum time permltted for the evaporation of urine particularly if the lit-ter box is used by more than one cat. It has been found that if the urine is not evaporated wlthin a short period of tlme that the bacteria have sufficient ~ ~7~28 tlme to attack the urine and begin the o~ior problem. Quite obviously this time factor will tend to be shorter on a warm day than on a cold day, due to the temperature dependency of the bacterlal action.
Ordinarily, In cat boxes, the greater the quantity of litter the less Is the odor. However"n this system the use of less litter is best since the drier the environment the less favorable are the conditions for the growth of bacteria andconventional litters tend to retard the loss of moisture. Thus, while the recom-mended depth of litter is two to three inches, in the instant system the use of about one half to one inch of litter is preferred.
The loft or density of the absorbent material is seen to have an effect on the evaporation rate since a relatively high loft fibrous mass provides for better aeration and evaporation. Whereas a low loft ~hlghly compacted) absorbent tends to restrlct the essential air flow, the greatest benefit is attained wlth a hlghloft material. The superabsorbents, of course, are extreme examples of a highly compacted absorbent which has much less surface area per ounce than the high loft fiberous absorbent.
It is noted that in sorbent pads, such as those used as disposable diapers for children or as incontinence pads for adults, evapora~ion is not a factor of con-cern since the pad traps the urine and holds it between a moisture Impermeable liner and body of the user. The factors which are critical in human applicationsare liquid absorption and wicking effects only.
Evaporation rate maximization can be achieved, in part, if the urine travel within the pad is maximized; that Is the wicking effect of the sorbent medium should be such that the urine distributes rapidly acros~ the surface of the pad 2~ thus maximizing the surface area of the urlne exposed to the atmosphere. In this regard it is noted that short fibers will have a larger surface area than long fibers, but long fibers optimize the wicking effect of the sorbent pad.
One of the ma30r drawbacks of the conventional litter used in cat litter boxes is that the litter tends to retain the urine and retard urine evaporation.Similarly, the so called 'super sorbent"naterials, such as Dow Water Absorbent Laminate grade DWAL3~R sold by Dow under the trademark DWAL, haYe an ex-tremely high ratlo of llquid sorbents to material mass, causing the material toretain urine or other li~uids and stay wet for a long period of time. By way of contrast, sorbent materials from wood pulp fibers do not have the high ab-sorbency capacity of the Dow material, but haYe a greater ability to distribute Page I O
131~8~8 the urine across the pad and achieYe the evapo~atlon of the urine. Since urine evaporation has been determined to be the key factor in odor prevention, the use of a large amount of cat litter should be avoided. While the use of no lit-ter at all would be optimum from the standpoint of odor prevention, it is dif-ficult to train animals to use a pad that does not have litter present. More over, the litter does have a beneficial effect in combination with solid wastes and cats will tend to not use the litter box which does not have litter when defecating. Thus, while the use of two or preferably three inches of litter is commonly recommended for litter boxes, it has now been found that the use of less than one inch and preferably from about one quarter inch to about one half inch of litter produces the optimum combination of solid waste handling charac-teristics, economy of material and minimum urine evaporation prevention.
The quantity of litter employed in the system is significantly less critical when the teachings of the instant invention are followed.
Sand is a well known medium for use as cat litter. The sand particles do not appear to absorb the urine, in the manner that clay and other commercial litters absorb and hold large quantities of urine. In the case of sand, the urine appears to be held by surface tension within the densely packed material. The use of typical sand, such as employed in children's sand boxes can function to retard odor formation only so long as there is a great mass of material. Thus, in the case of sand, many inches of this litter would be required. As evident from the graph of Figure 3, the fine sand is better than an absorbent litter, from the standpoint of evaporation, but the urine tends to puddle beneath the sand in the litter box and odor forms rapidly unless large volumes of sand are used. Thus, sand is not an acceptable medium for household use as a litter in a cat litter box. The combination of fine sand with an absorbent pad does not produce an appreciable evaporation rate change over the use of the sand alone.
From a evaporation standpoint it is better than the combination of an absorbent litter with an absorbent pad, but tends to be less effectlve than than the litter-absorbent pad system. The decreased efficacy is probably due to the fact that the evaporation rate is too low to be e~ffective. Un]ike absorbent litter, the sand tends to accumulate the urine in a wet form, while, llke the absorbent liter, it retards the efficacy of the absorbent pad.
Surprisingly, although fine sand does not provide the desired results, the use of a coarse sand in combination with an absor~ent litter pad can produce results ~3~7~28 which Inltially surpass those attalned with the absorbent pad by itself and longterm closely approximate the results attained with an absorbent pad by itself.
It should be noted that the use of the absorbent/desiccant pad by itself would appear to provide the maximum evaporation rate. It has been observed, nevertheless, that the cornbination of the coarse sand with the absorbent pad produces a synergistic effect, at least initially, because the coarse sand broadly distributes the urlne across the absorbent pad. The exposed, upwardly disposed portion of the absorbent pad can be seen to become rapidly wet when the sand is wetted with about 300 ml. of water~ By way of contrast, In the case of ab-sorbent litter, fine sand and an absorbent pad by itself, the water is initially in a small area of only several inches In diameter. The fine sand is densely packed and consequently tends to both inhibit the travel of the urine to the ab-sorbent pad and the evaporation from the absorbent pad. It is this evaporation Inhibition which normally renders critical, the use of a minimum amount of a non-absorbent litter. Users who are accustomed to the use of three or more Inches of litter must dramatically change their habit in order to achieve the desired results. By way of direct contrast, the coarse sand both widely dis-tributes the urine and permits free evaporation. Consequently, the use of coarsesand is more forgiving, that is, there is a wider latitude in the amount of coarse sand which can be used. Nevertheless, it is preferred that the coarse sand be limited to use in a layer of about one quarter to three quarters of an inch. Because in a cat litter box, the litter is rewetted ever two to tour hours, depending upon the number of cats using the box, the diet of the cat, etc., the long term effectiveness of the odor prevention system Is dependent upon the ability to remove the urine from ehe system. Since in an absorbent litter system, the quantity of urine retained in the system increases with time,it is evident that the system will become overwhelmed by the mass of the urlne and wili loose its abiiity to prevent odor. Thus, It should be evident that the maximumization of evaporation is critical to prolonging of the useful life of the odor preventing system.
It is noted that the use of the large pebbles, has several draw backs. As the size of the granules increase substantlally above the ciuarter Inch diametersize, particularly above one half inch In diameter, there is an increasing ten-dency of the cats to reject the medium, probably because of the interference with the digging instinct. Moreover, the observed evaporation rate decreases, ~3~8~8 probably due to the decreased ability to widely distribute the urine over the ab-sorbent pad.
BACKGROUND OF TH~: INVENTION
Field of the Inventlon Thls invention relates to a specific non-absorbent litter for use In combina-tion with an a~sorbent medium for odor prevention in animal litter units. In partlcular the litter can be a mineral particle, such as coar~e sand, and the ab-sorbent pad can be a disposable, sorbent/dessicant pad~liner system.
Brlef Descrlption of the Prior Art Many domestic animals frequently use litter boxes for the elimination of body wastes. The boxes are usually filled wlth various kinds of granular materials such as sand, cat litter and the like, and must be periodically emptied and cleaned, which are somewhat objectionable tasks, since the absorbent granular ma~erial must be replaced and the boxes cleaned each time~
Cats, being the most frequent users of litter boxes, present a further problem in that the urine of the feline contains the highest content of urea which, when allowed eo stand for any length of time In any sorbent material, releases an am monia odor. This odor is one of the more obJectlonable factors in the ownership of a cat.
In order to eliminate the odor caused by cat urine, the lltter box must be changed frequently, necessitating the expensive, laborious and unpleasant chore.Summary of the Invention In accordance with the instant invention the foregoing prob~ems are overcome and an easy to use~ odorless, disposable sorbent pad system is provided. It has now been found that the ei ficacy of the dlsposable sorbent system can be op-timized if the absorbence of urlne in the lltter is mlnimlzed and eYaporation from the system is maximlzed~ Non-absorbent mlneral particles allow for the rapid entrance of the cat urlne Into the sorbent pad. The sorbent pad, can be constructed from high wicking capability materials. The formatlon of the odor associated with cat litter boxes is prevented by drylng, thus Inhlbltlng the bac-terial action on cat urine. The cat urine is transferred directly from overlylnglitter particles, through a cat claw resistant screen into a sorbtlve-deslccant member of fibers and having high surface area and high urine sorbency. The urine disperses quickly from flber to fiber in the sorbtive-desiccant member.
The moisture impermeable sheet preven~s urine from leaving the side of the sorbtive-desiccant member opposite the screen. The screen and the fibers of the sorbtive-desiccant member provlde for transport of moisture, alding the drying process of the urine, thus Inhibiting the growth and bacterlal action of bacteria.
13~ 28 Consequently, the bacteria die or become dormant thereby preventing slgniflcant odor form ation.
BRIEF DESCRIPTION OF THE DRAWINGS
The advantages and objects of the invention will become apparent and the Invention will be more fully understood from the following specificatlon, par-tlcularly when read In conJunction with the drawings, whereln:
FIGURE I is a top perspectlve of the assembled unit In accordance with the present Invention;
FIGURE 2 is an exploded fragmentary view of the sorbent pad of the instant invention;
FIGURE 3 is a graph which compares evaporation rate for several materlal and plots time versus quantity of water evaporated and retalned.
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DETAILEV DEscRlpTloN OF T~IE INVENTION
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In order to provlde a clear undelstanding of the Ins~ant in~ent on, the various aspects of the InventIon are here~na'ter descr bed In d tall.
~ e sorbent pad structure of t:he instant inven-tion can include a pro-tective screening and a moisture impermeable liner. The protective screening that is fully disclosed in U.S. Patent 4,640,225, issued Febru-ary 3, 1987, is suited for use with the present invention. The screen must be capable of withstanding the clawing action of an animal such as a cat, thus protecting the sorbent pad and the moisture impermeable liner.
the holes in the screen are sized small enough to prevent the animal s claws from reaching the sorbent pad, while numerous and large enough to allow for air passage and rapid evaporation of liquids. The sorbent pad, constructed from high wicking capabi1ity materia]s, is positioned between the screen and the moisture impermeable material. Ille screen is sealed to moisture impermeable material along at least a substantial por-tion of their peripheral edges. The screen is a flexible member formed of strands -bonded at their intersections and is formed of a material which is sub-stantially inert to urine.
The formatlon of the odor associated with ca~ Iitter boxes Is ?revented byInhiblting the bacterlal actlon on cat urine. A sorbent pad structure is posi-tioned between a protectIve screening, capable of wlthstanding the clawing actlon of a cat, and a moisture impermeable liner. The cat urine is transferred directly from overlylng litter partlcles, through a cat claw reslstant screen into a sorbtlve-desiccant member of flbers and having hlgh surface area and high urine sorbency. The urlne disperses quickly from fiber to flber In the sorbtive-desiccant member. The moisture Impermeable sheet prevents urine from Ieaving the side of the sorbtive-desiccant member opposite the screen. The screen and the fibers of the sorbtive-desiccant member provide for aeratlon, thus inhiblting the growth and bacterial actlon of bacterla as well as ald the evaporation of the urlne from the sorbtive-desiccant member. Consequently, the bacteria die or become dormant, thereby preventIng slgnlflcant odor formatlon.
Cat urlne is normally sterlle, that is, free of bacterla which acts on the urine and produces the odor assoclated wIth cat urlne. Nevertheless, It has been found that If steps are taken to inhlbit the growth of, or cause the death of bacteria, odor formatlon can be prevented. It Is presumed that the bacteria present in the fecal excreta, or present in the lltter or alr borne bacteria ~3~782~
comes Into contact with the urlne, thereby producing an odor problem.
In accordance wlth the present invention steps are taken to prevent odor by killing the bacteria or Inhibltlng their growth, without havlng to resort to theuse of bacterlcldes.
Of all the varlous factors that Influence the growth of microorganlsms, water may be considered to be the most Important. Indeed, water may really be con-sidered a nutrlent since it forms ~he bulk of the cellular substance. Compared to higher organlsms, whlch regulate thelr water content to some extent, microor-ganisms are dependent upon the amount of water In the environment. For growth and multlplicatlon bacterla requlre hlgh concentrations of water in theirimmediate environment. In splte of thelr seemingly solld character and dry ap-pearance, agar media and other solid foods used for the cultivatlon of bacterla require hlgh concentrations of water as part of thelr composltion. When or-ganisms are grown on surfaces such as an agar plaee, hlgh humidlty can provide condltlons favorable to the development of mlcroorganlsms. Water acts as a sol-vent, and most metabolic activitles are conducted wlthln an aqueous envlronment in the cell. Water also serves as a catalyst by aiding or actually enterlng intomany enzymatic reactions. Turgidlty of the cell is dependent upon the presence of water. In turn, turgidity is affected by the surface tension (osmotlc tenslon) of the medium in which the organisms are suspended. It probably would be cor-rect to consider all bacteria as aquatic organisms.
Water is necessary for the existence and vlability of mlcro-organlsms. The effects of desiccation on the vlabllity of mlcroorganlsms provldes a good example of the Importance of water. Slow deslccatlon In the presence of alr Is most detrimental. Although many specles of mlcroorganlsms can survlve complete drying or desiccatlon for long periods, they do not grow under such condltions.
In a state of complete deslccation the metabolic processes must stop almost completely since these depend largely on osmosis, dlffuslon, lonlzatlon and the colloldal state, all of whlch are dependent In turn on hydratlon.
GRANULAR MATERIAL
Mlneral partlcles such as small pebbles, rocks, stones gravel, coarse sand and the llke previously unsuitable as a cat lltter material because of the lack of ab-sorbency or their abillty to hold urine that pools In the bottom of the lltter box can now be used as a more effectlve cat lltter box flller when used wlth ab-sorbent pads. Because of thelr Inherent ablllty to allow urine to rapidly draln ~L317~28 into the absorbent pad without impeding the flow or spread of the urine through out the pad and allowing for a more rapid evaporation of the urine back through the particles and through out the absorbent pad due to the more numerous air spaces between these largeT partlcles. Very fine pa}tlcle such as fine sand or soil, will not act a a good cat box filler because of the flow of urine into thepad is impeded by the numerous particles. The transmission of the wa~er vapor through these particles is also Impeded.
The granular materlal as employed In the instant inventlon is utilized to satisfy the digglng Instinct of the animal and therefore need not provide absorp-tive qualities. Conseque~ y, 3inexpensive non-absorbent materials, including naturally occurring materials such as coarse sand and gravel, or synthetic materials such as glass and polymer beads, can be used in accordance with in-dividual preferences. Unlike the commonly employed systems In which the granular material must be used In quantlty to provide the required absorptive qualltles and digging qualities, minimal ~uantlties of the granular material can be used, as described herein. The absorptlon quality of the layer 24 can provide the ~otal or the predominant deslccation effect.
Hence, proper sized non~ sorbent niineral particle cat box flller serves the functlon of actin~ as;
1. An attractive digging medlum for cats ~. Allows cat urlne to fall rapldly over the partlcles into the absorbent pad.
3. Allows cat urine to migrate rapldly withln the pad since ~t Is not drawn up and trapped on absorbent partlcles llnlng the interface of the cat litter-rip proof layer.
4. Rapid migration of urine within the pad allows for more rapld evaporation out of the pad.
5. Water vapor can escape up through the pad, through the mineral litter par-ticles.
6. In addition to e~aporation from the absorbent pad, the mlneral particles wet by the vold will dry and hence the effective surface area producing evaporatlon is greater for the combination of the pad with wetable non-absorbent particles than with the absorbent partlcles and absorbent pad.
7. Mineral particles wet by the previous vold wlll become dry due to both dralnage and evaporation ancl thus the suriace area of non-absorbent partlcles avallable for alding in evaporatlon is maintained at a maximum value. (By way Page S
~ 3~7~28 of contrast, absorbent litter particles stay wet and lose thelr ability to function as an absorbent and an evaporation surface.) 8. The heavy mlneral particles scatter out of the litter box less than light weight clays and similar absorbent litters.
9. The washed mineral particles contain less dust than clay and is not friable therefor creates no dust of its own.
The litter material is commonly in granular form and must be in moisture transfer contact with the underlying sorbent material so that the urine can be drawn from the litter material into the sorptive layers. The use oi a surfactanton the screen m aterial can enhance the moisture transfer capability of the screen and is essential in combination with hydrophobic or low hydrophilicity screen materials. The particle size distribution can range from a few mil-llme~ers to several centimeters. Flne sand having a particle size at the lower end of sands, that is at the 200 mesh (0.074 mm.) slze pac~ so densely as to limie or restrict liquid and air flow between the particles. At the upper end ofthe particle size the sand or gravel material can be reJected by the cats and fail to enhance the distributlon of the liquid across the absorbent pad, as evident from the test and the graph of Figure 3.
While reference has been made in partlcular to sand, it should be understood that non-absorbent materlals, in partlcular other inorganic mlnerals, in generalwill provide similar results.
Particularly suited to the instant invention is a coarse sand referred to as fine gravel commonly found in central New Jersey. These gravels and sands were deposited during the formation of the early coastal plaln The sands and gravels consist mostly of quartz or silica. The available particles are found in a wide range of particle slzes and must be sieved to obtain the deslred particle size distribution. The non-absorbent particles must be sufflciently free of friable materlals, such as clay, In order to avold the fllling of the Interstlces. The particles can be as small as one millimeter in diameter and as large às three centimeters. The preferred range, however, Is between two millimeters and about one centimeter. It should be understood that the partlcles typically are not round, but rather, most typicall~ are oval or irregular in shape and the dlameter referred to Is the average diameter of the particle. The particles are washed to get rld of the small dust particles and then air or oven dried prior to use as a non-absorbent litter.
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Eor acs~hetic effect, the particles can bc dyed to a particular color. Mor-dant dyes can be used where the partlcles are sillca. Ttle particles can bc coated to moderate the hydro-pl1obicity or hydropllllicity of the surface of theparticles. The use of waxes, sillcons, and the like can be used In this regard.
Although glass beads, Teflon * (T.M. ) coated particles, polypropylene or polyethylene, synthetic and natural resins can serve as the same function as non-absorbent coarse sand or fine gravel, a large number of cats will reject the use of these products as a cat box filler. Very large particles such as large pebbles or gravel, rocks, etc., tend to be very heavy and easlly packed ~hen used as a catbox filler and also can be rejected by cats. Digglng Is difficult with large heavy particles and can also lead to rejection by cats. The coarse sand, on the other harld, mlrnics the appearance ol the comrnercially available absorbent c13v litters, is readily used by the cat for digging and as a waste matter repositoryand has the further advantage of resisting scatterlng and tracking by the cat.
In addition, the non-absorbent granules are non frlable and dustlng is consequentl-nega t ed. -ABSORBENl` UN-11`
The absorp~ive elements can be an~ material such as paper, tlssue, pulp starch and related polymers, etc. ~4hich can disperse the llquid quickly, thus providing a large surface area for evaporation of moisture. In order to rnaintain a moisture free environl1lent~ it is necessar~ to evaporate from a to 20 ml. o~
liquid each time the s-s;em is used by the cat.
Examples of sorben~ materials are those manufactured by Do~ Chemical and marketed under U.S. Patent 4,117,18~. This product is commonly identified as c~
super absorbent and sold by Dow Chemical Company under the desi~nation D~1AI. 35 !~.
( T . M . ) Alternativcly, the super sorbent can be a material such as the National Starch and Chemical Corporation procluct sold under the registered trademark PER,~ASORB. l he National Starch product is a h~drophillc polymer which has the abillty to absorb and hold urlne. There is a slgnlficant reduction in urine odor and pH level In the presence of PERMASORB.
Another eY; mple of an absorbent is the material sold under the trademark WATER-LOCK by Grain Processing Corp.
In contrast to the ultra-h~gh absorbency materlals, ground paper pulp absorp-~3~7~2~
tlve material has becn found to provide a combination of hlgh absorbency, highsurface area and low cost. The large surface area provides for rapid urine evaporatlon and consequently is extremely effeceive in odor prevention.
Toxic chemicals or blologlcally active ingredlents are not only unnecessary but preferably are avolded. U.S. patent 4,494,482 assigned to Proctor and Gamble relies on the use of 5000 to 30,000 ppm of a halogenated aromatic hydrocarbon bacteriostat in an sorbent pad to effectively control odor develop-ment. It has been found that If the sorbent materlal has the abillty to absorb the urine, distribute the urine rapidly throughout its mass, and evaporate the urine faster than the bacteria can act on the urine, then the additives are not only unnecessary but undesirable.
Bacteria froln the feces cannot grow in the absorptive layer because they are dried out and die or become dormant. It is the bacteria which is capable of breaking down the urine which cause the strong volatlle odor commonly as-sociated with cat lltter boxes, the dry environment of the sorbent material ef-fectively prevents odor. The high absorption capacity of the super absorbent polymers, such as available from Dow Chemical, do not provide an advantage over a pulp flber, due to the hlgh rate of evaporation of urine from the flberous materlal. As previously stated, the instant inventlon requlres substan-tially less granular material for each use and requlres fewer changes, saving fur-ther on granular use. In the prior art ~ype of lltter box, the lltter consumption is greater than in accordance with the present inventlon.
The amount of litter which is used can be decreased wlth time In order to permit the cat to become accustomed to the low litter level. In some cases, cats can be tralned to the pads without lltter. Whereas, in conventional litter boxes, two to three inches of litter are required, in accordance w!th the present Invention less than one Inch of lltter, and preferably no more than about one half inch, provides the deslred rssults, as evldent from the chart which appearshereinafter.
It has been found thst the use of over an inch of an absorbent lltter can actually retard the moisture evaporation, apparently due to the litter serving as a moisture barrier between the sorbent unit and the atmosphere~ In actual use it has been found that the clawlng and scratching of the cats tends to expose reglons of the screen or at least greatly reduce the amount of lltter covering csrtaln regions of the screen. Although the ideal system would be free of litter ~ 3~2~
the cats tend to reject a litter container which is totally lltter free. The useof a non-absorbent litter which does not pack, or conversely, which permits the sorbent unit to "breath" minlmizes the adverse effects of standard litters.
Figure I illustrates the assembled unit 10 of the instant invention. The granular material 20 Is placed on top of the sorbent unit 12 to provide the snimal with the necessary scratching materials, if so required~ The granular materlal would not be requlred If the unit was being used for a dog or other animal which did not have the scratching instinct.
The sorbent unit can be used with standard litter boxes and can be combined with the adhesive securing means, elastici~ed securing means or any other method disclosed in copending applications.
Fi~ure 2 shows, in exploded form, a cross-section of the layers which form the sorbent unit 12. The outer layer 22 which is a thin plastic sheet of a material such as polypropylene or polyethylene prevents waste from making con-tact with the box and can double as a bag when disposing of the soiled litter.
A protective layer 26, which can be used, If desired, is made from a durable, non-woven tlssue substance. If a binder Is used for either the fabric of the tissue layer or o~her layer, it must be of a non-water soluble material.
The protective screen 28 is of a flexible7 durable substance which prevents the animal from scratching through to the bottom layers. The granular material ~0 isplaced on top of the sorbent unit as previously described herein.
Urine evaporation tests were conducted for the purpose oî comparing the evaporation rates of a variety of materials. in one instance the quantity of water was contained in a bowl having an eight inch diameter. In all instances 9 milliliters of liquid were tested since this represents the average amount of urine deposited on a litter pad by a cat each tlme It uses a pad. Qulte obviously a young kitten will ~ass less liquid than a large adult cat. Statistically it has been determ~ned that cats will void once every four hours and the quantity of liquid will be about 9 milliliters. In the event that the rate of evaporation ofthe urine is slower than the rate of deposit of urlne in the pad, the pad will never reach a dry state and the odor associated with bacterial action on urine can not be prevented. It should be noted that a four hour time limit is beyond the maximum time permltted for the evaporation of urine particularly if the lit-ter box is used by more than one cat. It has been found that if the urine is not evaporated wlthin a short period of tlme that the bacteria have sufficient ~ ~7~28 tlme to attack the urine and begin the o~ior problem. Quite obviously this time factor will tend to be shorter on a warm day than on a cold day, due to the temperature dependency of the bacterlal action.
Ordinarily, In cat boxes, the greater the quantity of litter the less Is the odor. However"n this system the use of less litter is best since the drier the environment the less favorable are the conditions for the growth of bacteria andconventional litters tend to retard the loss of moisture. Thus, while the recom-mended depth of litter is two to three inches, in the instant system the use of about one half to one inch of litter is preferred.
The loft or density of the absorbent material is seen to have an effect on the evaporation rate since a relatively high loft fibrous mass provides for better aeration and evaporation. Whereas a low loft ~hlghly compacted) absorbent tends to restrlct the essential air flow, the greatest benefit is attained wlth a hlghloft material. The superabsorbents, of course, are extreme examples of a highly compacted absorbent which has much less surface area per ounce than the high loft fiberous absorbent.
It is noted that in sorbent pads, such as those used as disposable diapers for children or as incontinence pads for adults, evapora~ion is not a factor of con-cern since the pad traps the urine and holds it between a moisture Impermeable liner and body of the user. The factors which are critical in human applicationsare liquid absorption and wicking effects only.
Evaporation rate maximization can be achieved, in part, if the urine travel within the pad is maximized; that Is the wicking effect of the sorbent medium should be such that the urine distributes rapidly acros~ the surface of the pad 2~ thus maximizing the surface area of the urlne exposed to the atmosphere. In this regard it is noted that short fibers will have a larger surface area than long fibers, but long fibers optimize the wicking effect of the sorbent pad.
One of the ma30r drawbacks of the conventional litter used in cat litter boxes is that the litter tends to retain the urine and retard urine evaporation.Similarly, the so called 'super sorbent"naterials, such as Dow Water Absorbent Laminate grade DWAL3~R sold by Dow under the trademark DWAL, haYe an ex-tremely high ratlo of llquid sorbents to material mass, causing the material toretain urine or other li~uids and stay wet for a long period of time. By way of contrast, sorbent materials from wood pulp fibers do not have the high ab-sorbency capacity of the Dow material, but haYe a greater ability to distribute Page I O
131~8~8 the urine across the pad and achieYe the evapo~atlon of the urine. Since urine evaporation has been determined to be the key factor in odor prevention, the use of a large amount of cat litter should be avoided. While the use of no lit-ter at all would be optimum from the standpoint of odor prevention, it is dif-ficult to train animals to use a pad that does not have litter present. More over, the litter does have a beneficial effect in combination with solid wastes and cats will tend to not use the litter box which does not have litter when defecating. Thus, while the use of two or preferably three inches of litter is commonly recommended for litter boxes, it has now been found that the use of less than one inch and preferably from about one quarter inch to about one half inch of litter produces the optimum combination of solid waste handling charac-teristics, economy of material and minimum urine evaporation prevention.
The quantity of litter employed in the system is significantly less critical when the teachings of the instant invention are followed.
Sand is a well known medium for use as cat litter. The sand particles do not appear to absorb the urine, in the manner that clay and other commercial litters absorb and hold large quantities of urine. In the case of sand, the urine appears to be held by surface tension within the densely packed material. The use of typical sand, such as employed in children's sand boxes can function to retard odor formation only so long as there is a great mass of material. Thus, in the case of sand, many inches of this litter would be required. As evident from the graph of Figure 3, the fine sand is better than an absorbent litter, from the standpoint of evaporation, but the urine tends to puddle beneath the sand in the litter box and odor forms rapidly unless large volumes of sand are used. Thus, sand is not an acceptable medium for household use as a litter in a cat litter box. The combination of fine sand with an absorbent pad does not produce an appreciable evaporation rate change over the use of the sand alone.
From a evaporation standpoint it is better than the combination of an absorbent litter with an absorbent pad, but tends to be less effectlve than than the litter-absorbent pad system. The decreased efficacy is probably due to the fact that the evaporation rate is too low to be e~ffective. Un]ike absorbent litter, the sand tends to accumulate the urine in a wet form, while, llke the absorbent liter, it retards the efficacy of the absorbent pad.
Surprisingly, although fine sand does not provide the desired results, the use of a coarse sand in combination with an absor~ent litter pad can produce results ~3~7~28 which Inltially surpass those attalned with the absorbent pad by itself and longterm closely approximate the results attained with an absorbent pad by itself.
It should be noted that the use of the absorbent/desiccant pad by itself would appear to provide the maximum evaporation rate. It has been observed, nevertheless, that the cornbination of the coarse sand with the absorbent pad produces a synergistic effect, at least initially, because the coarse sand broadly distributes the urlne across the absorbent pad. The exposed, upwardly disposed portion of the absorbent pad can be seen to become rapidly wet when the sand is wetted with about 300 ml. of water~ By way of contrast, In the case of ab-sorbent litter, fine sand and an absorbent pad by itself, the water is initially in a small area of only several inches In diameter. The fine sand is densely packed and consequently tends to both inhibit the travel of the urine to the ab-sorbent pad and the evaporation from the absorbent pad. It is this evaporation Inhibition which normally renders critical, the use of a minimum amount of a non-absorbent litter. Users who are accustomed to the use of three or more Inches of litter must dramatically change their habit in order to achieve the desired results. By way of direct contrast, the coarse sand both widely dis-tributes the urine and permits free evaporation. Consequently, the use of coarsesand is more forgiving, that is, there is a wider latitude in the amount of coarse sand which can be used. Nevertheless, it is preferred that the coarse sand be limited to use in a layer of about one quarter to three quarters of an inch. Because in a cat litter box, the litter is rewetted ever two to tour hours, depending upon the number of cats using the box, the diet of the cat, etc., the long term effectiveness of the odor prevention system Is dependent upon the ability to remove the urine from ehe system. Since in an absorbent litter system, the quantity of urine retained in the system increases with time,it is evident that the system will become overwhelmed by the mass of the urlne and wili loose its abiiity to prevent odor. Thus, It should be evident that the maximumization of evaporation is critical to prolonging of the useful life of the odor preventing system.
It is noted that the use of the large pebbles, has several draw backs. As the size of the granules increase substantlally above the ciuarter Inch diametersize, particularly above one half inch In diameter, there is an increasing ten-dency of the cats to reject the medium, probably because of the interference with the digging instinct. Moreover, the observed evaporation rate decreases, ~3~8~8 probably due to the decreased ability to widely distribute the urine over the ab-sorbent pad.
Claims (3)
1. In the combination of a cat litter box, a dessicant/absorbent member and litter, the improvement wherein said litter is substanti-ally non-absorbent particles having an average particle size of at least sufficiently large diameter to provide sufficient interparti-cle spacing to permit free flow of urine from the particles to said sorbtive-desiccant member and the free flow of water vapor from said sorbtive-desiccant member into the atmosphere and wherein said non-absorbent particles are substantially free of smaller particles hav-ing a size such that said smaller particles fill the spaces between adjacent non-absorbent particles and consequently inhibit air flow between adjacent litter particles.
2. The combination of claim 1, wherein said litter is mineral par-ticles.
3. The combination of claim 2, wherein said mineral particles have an average particle size greater than about one millimeter.
g. The combination of claim 2, wherein said mineral particles are coarse sand having an average particle size greater than about one millimeter.
5. The combination of claim 3, wherein said mineral particles have an average particle size no greater than about three centimeters.
6. The combination of claim 5, wherein said mineral particles have an average particle size in the range from about two millimeters to about one centimeter.
7. The combination of claim 4, wherein said particles have an av-erage particle size in the range from about two millimeters to about one centimeter.
8. The combination of claim 1, wherein said particles have an av-erage particle size in the range from about two millimeters to about one centimeter and are substantially free of friable particles.
9. The combination of claim 1, wherein said litter is substanti-ally free of friable particles.
10. The method of preventing the odor caused by the action of bac-teria on cat urine in a cat litter box having a base and walls, sorbtive-desiccant member for the collection of animal urine over-lying said base, said litter being in direct moisture transfer con-tact with said sorbtive-desiccant member, comprising the steps of:
a. transferring cat urine directly from granular litter par-ticles, to said sorbtive-desiccant member, said granular particles being non-absorbent particles having sufficient-ly large diameter to provide sufficient interparticle spacing to permit free flow of urine from the particles to said sorbtive-desiccant member and the free flow of mois-ture from said sorbtive-desiccant member into the atmos-phere;
b. sorbing said urine in a sorbtive-desiccant member having high surface area and high urine sorbency, and dispersing the urine quickly in said sorbtive-desiccant member;
c. preventing urine from leaving one side of said sorbtive-desiccant member by having said one side of said sorbtive-desiccant member in contact with moisture impermeable means;
d. maintaining the urine in a medium which subject the bac-teria in the urine to desiccation;
e. evaporating said urine from said high surface area sorbtive-desiccant member through said litter granular particles and causing the bacteria, which are capable of breaking down cat urine, to die or become dormant thereby preventing significant odor formation.
11. An evaporation device comprising, in combination, a dessicant/
absorbent member and substantially non-absorbent particles, said non-absorbent particles having an average particle size of at least sufficiently large diameter to provide sufficient interparticle spacing to permit free flow of liquid from the particles to said sorbtive-desiccant member and the free flow of vapor from said sorbtive-desiccant member to the atmosphere and wherein said non-absorbent particles are substantially free of particles having a size such that the particles fill the spaces between adja-cent non-absorbent particles and consequently inhibit air or vapor flow between adjacent non-absorbent particles.
12. The device of claim 11, wherein said non-absorbent particles are mineral particles.
13. The device of claim 12, wherein said mineral particles have an average particle size greater than about one millimeter.
14. The device of claim 12, wherein said mineral particles are coarse sand having an average particle size greater than about one millimeter.
15. The device of claim 13, wherein said mineral particles have an average particle size no greater than about three centimeters.
16. The device of claim 15, wherein said mineral particles have an average particle size in the range from about two millimeters to about one centimeter.
17. The device of claim 11, wherein said particles have an average particle size in the range from about two millimeters to about one centimeter.
18. The device of claim 11, wherein said particles have an average particle size in the range from about two millimeters to about one centimeter and are substantially free of friable particles.
20. The method of preventing the odor caused by the action of bac-teria in a nutrient liquid comprising the steps of:
a. depositing a nutrient liquid on substantially non-absorbent granular particles;
b. transferring said nutrient liquid directly from granular particles, to ? sorbtive-desiccant member, said granu-lar particles being non-absorbent particles having suffic-iently large diameter to provide sufficient interparticle spacing to permit free flow of urine from the particles to said sorbtive-desiccant member and the free flow of mois-ture from said sorbtive-desiccant member to the atmos-phere;
c. sorbing said nutrient liquid in said sorbtive-desiccant mem-ber having high surface area and high sorbency capacity for said nutrient liquid, and dispersing nutrient liquid quickly in said sorbtive-desiccant member;
d. preventing said nutrient liquid from leaving one side of said sorbtive-desiccant member by having said one side of said sorbtive-desiccant member in contact with moisture impermeable means;
e. maintaining the nutrient liquid in a medium which subjects the bacteria in the nutrient liquid urine to desiccation;
f. evaporating said nutrient liquid from said high surface area sorbtive-desiccant member through said non-absorbent particles means and causing the bacteria, which are capable of breaking the nutrient liquid, to die or become dormant thereby preventing significant odor formation.
g. The combination of claim 2, wherein said mineral particles are coarse sand having an average particle size greater than about one millimeter.
5. The combination of claim 3, wherein said mineral particles have an average particle size no greater than about three centimeters.
6. The combination of claim 5, wherein said mineral particles have an average particle size in the range from about two millimeters to about one centimeter.
7. The combination of claim 4, wherein said particles have an av-erage particle size in the range from about two millimeters to about one centimeter.
8. The combination of claim 1, wherein said particles have an av-erage particle size in the range from about two millimeters to about one centimeter and are substantially free of friable particles.
9. The combination of claim 1, wherein said litter is substanti-ally free of friable particles.
10. The method of preventing the odor caused by the action of bac-teria on cat urine in a cat litter box having a base and walls, sorbtive-desiccant member for the collection of animal urine over-lying said base, said litter being in direct moisture transfer con-tact with said sorbtive-desiccant member, comprising the steps of:
a. transferring cat urine directly from granular litter par-ticles, to said sorbtive-desiccant member, said granular particles being non-absorbent particles having sufficient-ly large diameter to provide sufficient interparticle spacing to permit free flow of urine from the particles to said sorbtive-desiccant member and the free flow of mois-ture from said sorbtive-desiccant member into the atmos-phere;
b. sorbing said urine in a sorbtive-desiccant member having high surface area and high urine sorbency, and dispersing the urine quickly in said sorbtive-desiccant member;
c. preventing urine from leaving one side of said sorbtive-desiccant member by having said one side of said sorbtive-desiccant member in contact with moisture impermeable means;
d. maintaining the urine in a medium which subject the bac-teria in the urine to desiccation;
e. evaporating said urine from said high surface area sorbtive-desiccant member through said litter granular particles and causing the bacteria, which are capable of breaking down cat urine, to die or become dormant thereby preventing significant odor formation.
11. An evaporation device comprising, in combination, a dessicant/
absorbent member and substantially non-absorbent particles, said non-absorbent particles having an average particle size of at least sufficiently large diameter to provide sufficient interparticle spacing to permit free flow of liquid from the particles to said sorbtive-desiccant member and the free flow of vapor from said sorbtive-desiccant member to the atmosphere and wherein said non-absorbent particles are substantially free of particles having a size such that the particles fill the spaces between adja-cent non-absorbent particles and consequently inhibit air or vapor flow between adjacent non-absorbent particles.
12. The device of claim 11, wherein said non-absorbent particles are mineral particles.
13. The device of claim 12, wherein said mineral particles have an average particle size greater than about one millimeter.
14. The device of claim 12, wherein said mineral particles are coarse sand having an average particle size greater than about one millimeter.
15. The device of claim 13, wherein said mineral particles have an average particle size no greater than about three centimeters.
16. The device of claim 15, wherein said mineral particles have an average particle size in the range from about two millimeters to about one centimeter.
17. The device of claim 11, wherein said particles have an average particle size in the range from about two millimeters to about one centimeter.
18. The device of claim 11, wherein said particles have an average particle size in the range from about two millimeters to about one centimeter and are substantially free of friable particles.
20. The method of preventing the odor caused by the action of bac-teria in a nutrient liquid comprising the steps of:
a. depositing a nutrient liquid on substantially non-absorbent granular particles;
b. transferring said nutrient liquid directly from granular particles, to ? sorbtive-desiccant member, said granu-lar particles being non-absorbent particles having suffic-iently large diameter to provide sufficient interparticle spacing to permit free flow of urine from the particles to said sorbtive-desiccant member and the free flow of mois-ture from said sorbtive-desiccant member to the atmos-phere;
c. sorbing said nutrient liquid in said sorbtive-desiccant mem-ber having high surface area and high sorbency capacity for said nutrient liquid, and dispersing nutrient liquid quickly in said sorbtive-desiccant member;
d. preventing said nutrient liquid from leaving one side of said sorbtive-desiccant member by having said one side of said sorbtive-desiccant member in contact with moisture impermeable means;
e. maintaining the nutrient liquid in a medium which subjects the bacteria in the nutrient liquid urine to desiccation;
f. evaporating said nutrient liquid from said high surface area sorbtive-desiccant member through said non-absorbent particles means and causing the bacteria, which are capable of breaking the nutrient liquid, to die or become dormant thereby preventing significant odor formation.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US90925678A | 1978-05-24 | 1978-05-24 | |
| US06/870,351 US4756273A (en) | 1978-05-24 | 1986-06-04 | Reversible bag for use with litter pad |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1317828C true CA1317828C (en) | 1993-05-18 |
Family
ID=27128152
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000605752A Expired - Fee Related CA1317828C (en) | 1978-05-24 | 1989-07-14 | Non-absorbent litter for use with absorbent pad |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US4756273A (en) |
| CA (1) | CA1317828C (en) |
Families Citing this family (27)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5025752A (en) * | 1981-10-27 | 1991-06-25 | Patrick Yananton | Non-absorbent litter for use with absorbent pad |
| US4972800A (en) * | 1990-01-03 | 1990-11-27 | Bennett Earl W | Pet litter box |
| US5062392A (en) * | 1990-04-10 | 1991-11-05 | The Procter & Gamble Company | Filtering and disposal system for pet litter |
| US5038721A (en) * | 1990-04-10 | 1991-08-13 | The Procter & Gamble Company | Animal waste collection system comprising nonsorbent, nonclumping litter, liquid sorbent means and filter |
| US5031578A (en) * | 1990-04-10 | 1991-07-16 | The Procter & Gamble Company | Pet litter box system which prevents the development of unpleasant odors |
| US7307031B2 (en) * | 1997-05-29 | 2007-12-11 | The Procter & Gamble Company | Breathable composite sheet structure and absorbent articles utilizing same |
| US5850798A (en) * | 1997-09-30 | 1998-12-22 | Engel; Eric M. | Cat-box liner |
| GB2346791A (en) * | 1999-01-30 | 2000-08-23 | Kevin Leslie Sax | Pet litter tray and liner |
| DE10012998B4 (en) * | 2000-03-16 | 2005-10-27 | Wilhelm Schreiner | Wet protection mat for animal transporters |
| EP1495068B1 (en) * | 2002-04-15 | 2005-11-09 | The Coca-Cola Company | Coating composition containing an epoxide additive and structures coated therewith |
| US7007635B2 (en) * | 2003-06-10 | 2006-03-07 | Kincaid Virginia E | Cat litter pods |
| US20050279290A1 (en) * | 2004-06-17 | 2005-12-22 | Barry Hyland | System and method for animal waste disposal |
| GB2425032A (en) * | 2005-04-15 | 2006-10-18 | Brenda Agnes Counsell | Animal toilet |
| US20070000446A1 (en) * | 2005-07-01 | 2007-01-04 | Dunn Steven B | System for handling and disposing of pet waste |
| US8438994B2 (en) * | 2007-02-28 | 2013-05-14 | Maureen Stratton | Disposable litter device and system |
| US9242282B2 (en) | 2008-04-28 | 2016-01-26 | Pharma-Cycle, Llc | System and method for disposal of mutagen waste |
| US20100242849A1 (en) * | 2009-03-31 | 2010-09-30 | Brent Alexander Newton | Pet bedding |
| US20130213317A1 (en) * | 2010-12-03 | 2013-08-22 | Earth Biochemical Co., Ltd. | Cat playing tool |
| EP2741653A4 (en) * | 2012-02-13 | 2015-05-13 | Pharma Cycle Llc | System and method for disposal of mutagen waste |
| FR3012942B1 (en) * | 2013-11-08 | 2016-01-01 | Michael Schmit | KIT OF FILTER BAGS FOR LITTER FOR CAT |
| US20160029589A1 (en) * | 2014-01-15 | 2016-02-04 | Zachary Norman | Pet waste system |
| US20150196004A1 (en) * | 2014-01-15 | 2015-07-16 | Zachary Norman | Pet Waste System |
| USD783907S1 (en) | 2015-08-06 | 2017-04-11 | WKOL Design Research and Development, LLC | Disposable litter liner |
| US10383308B2 (en) | 2016-01-22 | 2019-08-20 | The Clorox Company | Clumping animal litter and method thereof |
| CN113543633B (en) | 2019-03-20 | 2022-10-28 | 四爪制品有限公司 | Disposable absorbent pad and method of treatment |
| US11918969B2 (en) | 2019-12-06 | 2024-03-05 | The Clorox Company | Low dusting, small clumping highly absorptive animal litter |
| GB2605396A (en) * | 2021-03-30 | 2022-10-05 | Hebe Studio Ltd | Litter box liner |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3284273A (en) * | 1962-07-13 | 1966-11-08 | John A Haslett | Absorbent pad |
| US3227137A (en) * | 1964-04-17 | 1966-01-04 | Goldman Jerome Norman | Sanitary container liner and method for making same |
| US3521624A (en) * | 1967-07-03 | 1970-07-28 | Johnson & Johnson | Microorganism growth inhibiting fiber products |
| US3735735A (en) * | 1971-04-14 | 1973-05-29 | Michael Etkin | Portable commode for pets employing removeable maintenance |
| US4047499A (en) * | 1976-04-05 | 1977-09-13 | George Janecek | Pet waste disposal device |
| US4136798A (en) * | 1976-08-16 | 1979-01-30 | Oberstein N | Flushable bedpan bag |
| US4640225A (en) * | 1981-10-27 | 1987-02-03 | Patrick Yananton | Odorless animal litter unit |
| US4469046A (en) * | 1978-05-24 | 1984-09-04 | Patrick Yananton | Odorless animal litter unit |
| US4279217A (en) * | 1979-05-21 | 1981-07-21 | Behringer Rebecca K | Liner for a litter box |
| GB2100581A (en) * | 1981-06-19 | 1983-01-06 | David Alexander Rutherford | Bag for packaging animal's droppings etc. |
| US4646685A (en) * | 1985-10-25 | 1987-03-03 | Arenz Mary M | Disposable litter box and sheet assembly |
-
1986
- 1986-06-04 US US06/870,351 patent/US4756273A/en not_active Expired - Lifetime
-
1989
- 1989-07-14 CA CA000605752A patent/CA1317828C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| US4756273A (en) | 1988-07-12 |
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| MKLA | Lapsed |