CA1192352A - Passive dosing dispenser containing selected calcium hypochlorite cake compositions with swelling control - Google Patents

Abstract

ABSTRACT
An article for sanitizing toilets comprising a dosing dispenser having a calcium hypochlorite cake composition housed within a reservoir, characterized in that the cake comprises an effective amount of a selected water-soluble salt. The cake is formulated such that upon contact with water it exhibits controlled swelling, i.e., it will swell less than a calcium hypochlorite cake made without said selected salt.

Description

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PASSIVE DOSING DISPENSER CONTAINING
SELECTED CALCIUM HYPOCHLORITE CAKE
COMPOSITIONS WITH SWELLING CONTROL

Janet M. Mueller Leonard E. Small TECHNICAL FIELD

The most specific technology to which this inve~tion relates is that of disinfecting devices adapted to dispe~se disinfectant solutions to the tank of a conventional toilet when it is flush~d.

BACKGROUND ART
Dispensers which are adapted to deliver dis-infecting or aesthetic ingredients to a toilet tank to condition water in the toilet tank and bowl are known.
The following commonly-owned reerences will serv~ as background ar~ for dosing dispensers and cakes o~ active ingredients used in combina~ion therewith, ; and are incorporated~herein~by reference:
U.S~ Pat. No. 4~171,546, Dirksing, issued Oct. 23, 1979;
U.S. Pat. ~oO 4,208,747, Dirksing, issued June 24, 1980;
U.S. Pat. No. 4,186,856, Dirksing, issued Feb. 5, 1980;
U.S. Pat. ~o. 4,216,027, Wages, issued August 5, 1980;
U.S. Pat. No. 4/200~606~ Kitko, issued April 29, 19B0;
U.S. Pat. No. 4,248,827, Kitko, issued Feb. 3, 1981i U.S. Pat. No. 4,253,951, McCune, issued March 3, 1981;
IJ.S. PatO No. 4J246rl2g~ Kacher, i~sued Jan. 20, 1981;
U.S. Pat. No. 4,251,012, Williams, issued Feb. 17, 1981;
U.S. Pat. No. 4~,247,070, Dirksing, issued Jan~ 27, 1981;
U.S. Pa-t. No. 4,302,350, Callicott, issued Nov. 24, 1981;
~.S. Pat. No. 4,281,421, Nyquist et al, issued Aug. 4~ 1981;
U.S. Pat. No~ 4,283,300, Kurtz, issued Aug. 11, 1981; and European Pat. Appln. 0,005,286, Nyquist, published ~ov. 14, 1979.
U.S. Pat. 4,208,747, Dirksingl issued June 24, 1980, discloses highly effective toilet tank dispe~sers which receive a dose volume of water from a toilet tank 3~

in which such a dispenser is placed every time the toilet is flushed. This patent teaches tha~ cleaning and disinfecting cakes can be used in such dispensers, but fails to address the specific problems posed by cer~ain types o cakes, particularly when hypochlorite cakes are placed inside the reservoir of such a toilet tank dispenser. One of these problems is that a cake of calcium hypoch}orite material immersed completely in the dosing liguid tends to deli~er excessively high levels of chlorine. Thus, the chlorine is used up too fast. Figs. 9-14 and 18 o U.S. Pat. 4,208,747, Dirksing, disclose "top-feed" dispensers in which such cakes are completely immersed in the dosing liquid.
he solution is dr~wn from above the cake. Such lS cake/dispenser combinations do not deliver a consistent amount o~ available chlorine over the life of the cake.
Dirksing also discloses a dosing dispenser of the "bottom-feed" type illustrated in Figs. 1-8 and 15-17.
Symmetrical rectangular-shaped cakes are used therein.
In such dispensers the bleach cake is only partially immexsed in dosing liguid in the reservoir, A second problem noted where the cake is com-pletely immersed in wa~ex is that the pourable fluid cap~ei~t~ o the dispenser reservoir increases over the life cycle of the product. As a result of this, a dispenser which has been i~ use for some time contains a larger mass of hypochlorite solution, c3mpared to the ~uantity ~ontained in the reservoir during the early usage life of the dispenser when the cake itself occupies a larger por~iQ~ of the reservoir volume.
Another problem with dissolving prior art calcium hypochlorite cakes in bo~tom~feed dispensers i5 excess swelling. Excess swelling of a cake can break the plastic dispenser case~ Excess swelling can cause a cake to hang up and not gravi~y feed into the dispenser reservoir resulting in waste of chemicals~ On the one hand, a swelling cake sized so small to avoid the hang ~9235~

up problem, results in an under utilization of dispenser space and a shorter life for the dispenser. On the other hand, if the dispenser is oversized to acco~o-date a larger cake size, the dispenser will be too 5 bulky to fit in many toilet tanks.
A partially dissolving cake is disclosed in commonly owned U~S. Pat. No. 4,281,421, Nyquist, Kitko and Stradling, issued August 4, lg810 The Nyquist et al~ patent is directed to a partially insoluble meta-silicate cake. I~ has been discovered that a drawbackto the metasilic~te cake in a bottom-feed dispenser is that much o~ the hypochlorite is wasted. All of the cake is not immersed in liquid and "leaching" w:ill not dissolve the active located in the top part of thP
cake. Anoth~r drawback is nonuniform delivery of the active.
An object of the present invention is to provide a dispenser and cake combination which delivers all of the a~ailable chlorine in the cake at a subs~an-tially uniform rate, over a long period of time, ~hroughout the life of the dispenser.
Other objects of the present invention will be apparent in the light of the following disclosure.
SUMMA~Y OF THE INVENTION
The present invention comprises a passive dosing dispenser, having a reservoir with a compartment housing a calcium hypochlorite cake which is gradually depleted as doses of water are routed through the dispenser reservoir. Each dosç of water contacts a lower portion of the cake, dissolviny a portion of thehypochlorite to form a hypochlorite solution for release at a later time. The invention is characterized in a selection of the water-soluble calcium hypochlorite cake composition in combination with said dispenser.
The cake comprises a water--soluble calcium hypochlorite material and a selected salt which controls the swell~
ing of the calcium hypochlorite material. Preferred ~235~

salts are selected from the group consisting of: lithium chloride, lithium hypochlorite, lithium sulfate, lithium sulfate hydrate, lithium hydroxide and equivalent calcium hypochlorite swelling control salts. The term "cake" as used therein means a calcium hypochlorite based cake, unless otherwise specified. The term "swelling control" as used herein means reducing the tendency of a cake to swell upon contact with water.
The cake of this invention will swell less than one without said effective amount of said salt. The reservoir compartment housing the cake, and the cake are so sized so that free space between the correspond-i~g cake suraces and dispenser walls will allow the cake to swell som0 while allowing the cake to gradually dissolve and gravity feed into the dose volumes of water which are routed through the reservoir until the cake eventually disappears. The practice of this in~ention saves chemicals and increases the effective life of the dispenser as compared to dispensers which contain calcium hypochlorite cakes which do not dissolve completely due elther to theix compositions or to excessive swelling.

BRIEF DESCRIPTION OF THE D~AWINGS
While the specification concludes with claims particularly pointing ou~ and dis~inctly claiming the present invention, it is believed the present invention will be bettar understood from ~he ollowing descrip-tion in conjunction with the accompanying drawings in which:
Figu 1 is a partially torn away perspective view of a bottom-feed passive dosing dispenser contain-ing a solid cake.
Fig. 2 is a simplified sectional view which shows a portion of a cycle of the dispenser shown in Fig. 1 and which view is taken along section line 2-2 of Fig. 1~

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Figs. 3, 4, 5 and 6 are perspective views of four different geometric forms of solid hypochlorite cakes.

DET~ILED DESCRIPTION OF THE INVENTION
__ The dosing dispenser of this invention is typically placed into the water tank of a toilet. The dispenser has means for receiving a dose volume of water from the flush tank of the toilet. The received water is routed to a reservoir within the dispenser 10 which contains the calcium hypochlcrite cake. The dispensex has means for immersing a lowermost portion of the cake to a predetermined depth in the received water to facilita~e dissolving a portion o the hypo~
chlorite for dispensing at a latex time. The cake is sized to initially occupy most of the cake compartment space within the dispens~r reservoir. The cake and the cake compartmen~ preferably have cake suraces and ver~ical compartmen~ walls which are parallel to each oth r. ~t is important that there is at least 0.4 cm ZO to 4 cms of free space be~ween the vertical cake sur-faces and the cake compartment walls. Som~ preferred free spaces are from ~.4 cm to 4 cms, 0.5 cm to 1.5 cms, and 0.5 cm to 2 cms.
The dispenser retains the hypochlorite solu-tion in substantial isolation from the body of toilet tank water during quiescen-t periods in between flushes.
The disp~enser also has means for releasing the hypo~
chlorite solution fxom the dispenser into the tank water in the fIush tank when the water drains from the ~ank into the toile~ bowl during flus~ing. Available chlorine typically at a level of from about 2 parts per million (ppm) to about 10 ppm is provided in the toilet bowl water. The hypochlorite solution formed in the dispenser reservoir generally contains from about 0.5 to about 15~ available ~hlorine. The solid cake 35~

composition of -this invention is formulated to slowly dissolve and "gravi~y feed" into the water of the reservoir of the dispenser and disappear af~er the toilet has been flushed a sufficient number of times to exhaust all of the hypochlorite in the cake.
The selected calcium hypochlori~e cake of this invention is a tableted solid composition compris-ing: (I) an effective amount of a water-soluble calcium hypochlorite cake swelling control salt selected from th~ group consisting of lithium hypochlorite material ~Form 2 0 , lithium hydxoxide, li~hium sulfate hydrate, lithium chloride and other water-soluble li~hium salts, and mixtures thereof; and (II) from about 10% to about 98% of a substantially s~able calcium hypochlorite material containing (i) from about 65% to about 78%
calcium hypochlorit~, and (ii) tne balance being a mixture of salts and other by-product materials normal to the manufacture of calcium hypochlorite.

Cake Pre~aration The compacted solid calcium hypochlorite cake compositions of this inven~ion may be prepared by conventional compacting procedure. For ~xample, gran-ules of calcium hypochlorite, e.g., HTH @~, and granules of the selected swelling control salts are mixed to-gether, and this mixture is ~hen pres~ed into a cake with a compacting machine. The granules are genexally in a size range of from about 50 micr~ns to a~out 1,000 microns prior to compacting. The compacted solids can also be formed by tabletting, "slugging," Chil50nating, or otherwise converting the granular hypochlorite mixture into compacted forms.
The compacted solids can be formed~ for example, in a conventional tabletting machine~ The granular calcium hypochlorite and granular swelling ~23~

control sal~ are initially weighed and then dry mixed to produc~ a homogeneous mixture. This resultiny mixture is then stamped into a tablet, i.e., a compact cake. Compacting may be accomplished at pressuxes of from abou~ 0.5 tons/square inch to abou~ 200 tons/square inch, pre~erably from about 1.0 tons/square inch to about 50 to~s/square inch, and most preferably from about 1.5 tons/square inch to about 5.0 tons/square inch. The compacting can be done on any conventional compacting apparatus, e.g., a Stokes Model R4 Tablet Press. The compacted cakes generally have a speciic gravity of abou~ 1.3 to about 2.3, preferably from about 1.5 to about 2Ø
The cake is formed into shapes with dimensions appropriat~ to fit the cake compar-tment of the gravity feed do~ing dispenser which hold~ the cake.
A preferred cake exhibits a geometric form that has nonuniform cross-sectional area, as mea~ured along at least a portion of its ver~ical height~ the area generally increasing with vertical height. Pre-ferred cakes o~ this type exhibit rounded or wedged tapered bottoms (see Figs~ 3, 4 and 6).

Method of Use The dosing dispenser of this invention is used as a disinfectant chlorine source in flush toiletsa The compac~ed compositions are placed within a dispenser which is used within the flush tank of the ~oilet. An operable "gravity feed'~ dispenser is shown in Figs~ l and ~O The compacted cakes should be of a size to fill from about 50~ to abou~ 90% of the vclume of the cake compartment surrounding the cake. Preferably about 50%
~o abou~ 70~. Some unoccupied space is needed to allow for proper feeding of the cake upon contact with water. Sufficient cross-sectional space between the cake and the cake compartmerlt walls is 3S~

important to avoid "cake hang-up," which results in chemical waste.
A dose volume of toilet tank water is intro-duced into ~he dispenser during a normal water rise in the flush cycle of the toilet, contacting the cake composition in the dispenser. ~his water remains in the dispenser i~ contac-t~with the lower portion of the cake. A~out 0.5~ ~o 20~, preferably 1% to 5~, of the total surface are~ of ~he cake is initially exposed to the water within the dispenser. During the time between flushes a portion of the hypochlorite dissolves in the water, thereby ~orming a relatively concentra-ted solution of hypochloxite. When the ~oilet is flushed, a dose of concentrated hypochlorite solution is discharged into the toilet bowl along with substantially all the water in the f lush tank.
Cake swelling control is important in the context of a dissolving cake in a bottom-feed dispenser.
The degree of swelling that can be tolerated depends on 20 the size o~ the cake relative to the size o ~he dis~
pensex cake compartment housing the cake which deter-mines cake life and functionalit~.

Calcium Hypochlorite The calcium hypochlorite raw material for the purpose of the present invention is preferably a solid, dry calcium hypochlorite granular material con~aining at least about 65% by weiyht of calcium hypochlorite and ahout 5% of water, ~he balance being materials usually resulting from the process of manu~acture, e.g., sodium chloride, calcium hydroxide, chloride and carbonate~ In a repor~ed practice of calcium hypochlo-rite manufacture, the calcium hypochlorite is obtained as a slurry containing crys~als of calciu~ hypochlorite dihydrate [Ca(OCl)22H2O] in a mother liquor sonsistiny ~9235~
_ 9 _ essentially of an aqueous solution of calcium hypo-chlorite and sodium chloride. The slurry is filtered on a rotary vaccum filter to produce a "filter cake"
that retains sufficient mother liquor to have a mois-ture content of 45% to 50% by weight. The filter cake,e~g., fxom an Eimco Filter, when dried directly yields the granular 70~ calcium hypochlorite o~ commerce.
However, if a highex concentration of calcium hypo-chlorite is d~sired, Ihe wet fil~er cake may be washed with water to remove some of th~ mother liquor and then filtered or centrifuged or otherwise processed to separate furthar quantities of liquid and to ~orm a wet filter cake which, on dryiny, produces granules which conkain rom about 85% to about 90% by weight of cal-cium h~pvchlorite.
The calcium hypochlorite content of ~hecalcium hypochlorite granules used in formulating compositions of this invention is ~enerally at least about 60% and preferably ranges from about 65% to about ~0 75~ by weigh~. The compound calcium hypochlorite contains about 100% available chlorine, thus a composi-tion containing 65% calcium h~pochlorite contains about 65~ available chlorine. Commercial calcium h~ochlor-ite usually contains at least about 65% availab~e 25 chlorine and, as manufactured, contains 71% to 73% of calcium hypochlorite and about 5% water. A com~ercial calcium hypochlorite containing about ~5% to about 72%
available chlorine is marketed under the name "H~H" by Olin Mathieson Chemical Corporation. ~ typical analysis of HTH ~ is as follows:

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Typical IngredientWeight Calcium hypochlorite 70 - 75 ca(OCl)2 Sodium chloride 4 - 23 NaCl Calcium hydroxide1.5 - 5 Ca(0~32 Calcium carbonate1.0 - 5 CaCG3 Calcium chlorateO.4 - 4 Ca(C103)2 Calcium chlorideO.5 ~ 3 CaC12 Watex 004 - 8~5 Pxocesses for preparing calcium hypochlorite material may be found in U.S. Pat. No. 3r953/354~
Faust~ issued April 27, 1976; U.S. Pats. Nos~ 3,639,284, Long et al., issued E~ebruary 1, 1972; and 3,560,396, Robson, issued February 2, 1371. Various calcium hypochlorite compositions contain varying amounts of Ca(OCl)2 as indicated herein.

welling Control Salts The solid cake compositions of this invention contain an e~fective amount of a swelling control salt.
"Swelling control salts" means water-soluble salts other than calcium hypochlorite which are compatibly incorporated into calcium hypochlorite compositions and provide reduced swelling for the cake compared to cakes made of essentially commercial grade calci~n hypochlorite material, such as HT~. Swelling control salts are commercially available. ~hey are selected inoxganic salts which are not reactive ~o calcium 23~æ

hypochloxite and provide reduced swelling con-trol of calcium hypochlorite material. Examples of pxeferred swelling control salts include lithium hypochlori-te, lithium hydroxide, lithi~n sulfate, lithium sulfate 5 hydra~e, lithium chloride, and mixtures thereof.
An efective amount of swelling control salt in a typical calcium hypochlorite cake compositio~ can ranye from about 1% to about 90% by weight of the cake, pre~exably a cake composition contains from about 2.5%
10 to about 40~ of added swelling control salt.
The choice of swellin~ control salts will affect the hydration and swelling of the ~ompacted cake on its initial exposure to the aqueous environment within the dispenser. To minimize cake s~elling and 15 improve dissolution Q~ the disinfecting composition, preferred calcium hypochlorite cake compositions include "Form 2" and sodium chloride~ Lithium hypochlorite, LiOCl~ a preferred swelling control salt is preferably obtained in i~s commercially available form referred to 20 herein as "Form 2", which contains from about 25% to about 35% o pure lithium hypochlorite with the balance being inorganic diluents and moisture. The pure com-pound lithium hypochlorite contains about 120% available chlorine, thus a omposition containing 10% lithium 25 ~ypochlorite receives about a 1~% available chlorine contribution from the lithlum hypochlorite component.
A commercial granular lithium hypochloxite, marked with U.S. Pat. No. 3,171,184, contains about 36% avail-able chlorine and is marketed under the trade name 3G 'IForm 2" ~y the Lithium Corporation of ~merica. A
typical analysis of i'Form-2"-`t as reported by the manu~acturex, is as follows:

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ELEMENTAL ANALYSIS
Wei~ht %
Ingredient Typical Maximum Minimum A~ailabLe chlorine 36 38 35 Lithium hypochlorite 30 31 29 Lithium 4.55.3 3.5 Sodium 18 22 14 Po-tas.~ium 3 6 2 Chlorides (total) 45 55 34 Sulfates 11 22 5 Chlorates 2 4 Carbonates 1.5 3 0.5 Chlorites 0.10~5 0.05 Hydroxides 0O5 1 0.2 Water ~ 7 9 4 TRACE METALS
- - --Metal TypicalMaximum Iron 7 ppm20 ppm Copper 1 ppm2 ppm Nickel 0.1 ppm0.5 ppm Mercury 0O05 ppm0.1 ppm Lead 0.5 ppm1 ppm Arsenic 0~1 ppm0~5 ppm Zinc 1.5 ppm 3.0 ppm 923~i2 CHEMICAL ~NALYSIS
... .. .. .
Weigh-t ~
Ingredient ~rypical uaranteed Available chlorine 36 35 LiOCl (~ctive ingredient) 30 NaCl 34 Na2SO4 and K2SO4 20 LiCl 3 LiC103 3 LiOH

H~O ?

PH~SICAL PROPERTIES:
Bulk Density: Loose, 58 lbs/cu.ft.
Packed, 65 lbs/cu.ft.
Particle Size, U.S. Standard Sieves: Standard, -10~70 : Special~ -10~20, -20~50 Processes for preparing lithium hypochlorite compositions are found in U.S. Pats. Nos. 2,590,794, Robson~ issued March 25, 1952; 2,534,781, MacMahon, issued December 19, 1950, and 3,171,814, Orazem et al., issued ~arch 2, 1965. The term "lithium hypochlorite"
used in the specification and claims includes commer-

2~ cially available lithium hypochlorite ma~erial~ such asForm 2. Various lithium hypochlorite compositions contain varying amounts of LiOCl, as indicated h~rein~
The preferred cake of this invention comprises "HTH" calcium hypochlorite and '~Form 2" at a weiyht ratio of from ~:2 to 19:1, and most preferably 302 to ~2~5~

9:1. Another preferred cake comprises "HTH" and lithium sulfate hydrate at a weight ratio of from 1:9 to 49:1, most preferably 19:1. Cake compositions of this invention can comprise "~TH" and lithium hydroxide 5 at a ratio of 4:1 to 19:1, preferably 9:1. Sodium chloride can be present in the cakes at levels up to 50%.
Selection o Swelling Control Salts The ~ollowing salts exhib.it cake swelling 10 control: Form 2 is most preferred dUP to its available chlorine ~ontent and excellent swelling control proper-ties; also preerr~d are li-thium sulfate hydrate;
lithi~n hydroxide; and lithium chloride.
Table I shows a list of ranges of HTH/salt 15 xatios that exhibit swelling co~trol.
TAB~E I
Most Pre- Less Pre-ferred % Confi- ferred % Confi-Salt ~TH/S lt dence* HT~Salt dence*
20 Form 290:10 ~o 99 or95:S to 90 60.40 more 90:10 Li.So4 H~O95:5 to 97.5 or98:2 to 95 2 10:90 more 95:5 LioH 90:19 to 99 or95:5 to 90 80:20 more 90:10 *This tells how confident one can be judging from statisltical test, iOe~ ~ tha-~ the ratio of HTH~salt combination is effective ln swelling control.

30 Amount of sw~lling = - 2 ~-where ~W 3 change in width due to swelling ~T = change ln thickness due to swelling

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Cake Swelling Test Proc~dure _ The following cake swelling test procedure was used ~o collect the data reported in Tables II
-through IV.
1. The cake ingredients, 100 gms, were weighed in glass jars and capped to keep out moisture.
2. The contents of the glass jars were poured into 77 mm x 42 mm die boxes and stamped using a Stokes Model R4 Tablet Press~ The length and width of the cakes were about 77 mm x 42 mm but the cake thicknesses varied fxom about 17 mm to 21 ~ due to the differences in the specific ingredients used.
3. The cakes wexe then reweighed to assure that each contained about 100 gms of ingredients and the width and thickness o each cake was measured in millimeters using a caliper and recorded.

4. Each ~ake was then placed into a 250 ml beaker.
The cake was propped up at an angle o~ ~about 80 with a plastic hanger (The hanger is generally described in U.S. Pat. No. 4,247,070, Dirksing, January 27, 1981. The hanger was not used for the purpose described in that patent, but was modified for this test. The hanger was placed upslde-down and the stem cut to the height of the beaker~)

5. Then, about 50 mls of distilled water were poured into each beaker containing the cake and a watch glass placed thereover.

6. ~t the end o~ 10 ~ays each cake was removed from its beaker and its width and thickness remeasured, just above the waterline, using a caliper, in milLimeters.

7. The difference between the sum of a cake's width and thickness initial measuremen~ (3) and the final measurement (6) represen~s the amount of cake swelling in millimeters~

The data in Table II show the amount of swelliny for various ~TH/salt cakes at a ra~io o 90:10 (screening test). ~he amount of swellin~ is the difference be-tween the sums of a cake's wi~th and thickness, meas-5 ured in millimeters, before and af~er contact withwater according to the Cake Swelling Test Procedure described herein. The salts shown below the line do not exhibit swelling control at the 90/10 level tested.

TABLE II
10Amount of Swellln~***
Number of Salt Mean (mm) SD*(mm) O~servations LiOH 1.86 .76 7 LiCl 3.37 .81 4 MgSO4** 4-05 .91 3 Form 2 4.99 1.73 9 Li2S4 5.17 2.21 6 ~i2C3 6.91 2.3~ 4 Na2SO4 7,47 3,93 4 CaCl~ 7.96 2.88 4 Ca3(PO4)28.54 .62 2 Ca(OH)2 8.74 1.50 5 ~2S~4 9.22 1.79 N 2C 3 9.24 3 17 4 Li3PO4 9~76 2O29 4 Na3PO4 10.03 2.85 K2CO3 I0.25 3.94 3 Mg(OH)2 10.48 1~67 5 CaCO3 10~54 1~82 4 KCl 10.67 3.51 4 CaSO~ 11.04 1.40 5 NaCl 11~48 2.30 4 K3PO4 12.16 3.15 HTH 7.69 2.49 12 35ii~

*Standard deviation **Cakes made with MgSO were too soft for preferred compositio4s of this invention.
***Tested at 80F/80%RH and 80~F and 40F/
ambient humidity atmosphere surrounding the test beakers.

Table IIA reflects the percent of confidence.

T~BLE IIA
Degrees Of - calc tgS tg7 5 tgg tgg 95 Freedom ~ l7.53 1.74 2.11 2.57 3.97 17 LiCl5.24 1.76 2.15 2.62 4.14 14 MgSO44.09 1.77 2.16 2.65 4.22 13 Form 22.93 1.73 2.09 2.54 3.88 19 Li2SO42.18 1-75 2.12 2.58 4.02 16 Li~CO3.57 1.76 2`.15 2.62 4.~4 14 *The value of t at 95~ confidence; the subscripts show the amount of confidence.

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The data shown in Table III and Ta~le IIIA
reflect the amount of swelling for various HT~/E'orm 2 ratios and the degree of confîdence. Swelling is the diffexence between the sums of a cake's width and S thickness, measured in millimeters, beore and after contact with water according to the Cake Swelling Test Procedure as described herein.

TABLE III
Amou~t of Swelling*~
Number of HT~/Form 2 Mean (mm) SD*(mm~ Observations __ 100/0 7.69 2.49 12 99.9/.l 8.21 2.12 2 99/1 7.71 .33 2 15~8/2 9.29 1.30 3 g5/5 6.07 1.26 90/10 : 4.99 lu73 g ~0/20 2.93 1.08 6 ~070/30 2.99 .77 4 60/40 3.06 .92 3 S0/50 ~.07 3.4S 3 ~0/60 10.0 30/70 17.68 2.25 3 2~10/90 21~08 4.~7 3 5/95 2~.0 0/100 13.32 ~.43 6 *Standard deviation *~80F/ambient humidity atmosphere ~urroundin~ the test beaker ~9~

TABLE IIIA

HTH/F2 95/590tlO 80/20 70/30 60/40 tcalc 1.692.93 5.64 5.76 5.18 tgo 1.351.33 1.34 1~35 1.35 5 tg5 1.761.73 1.75 1.76 1.77 t~7 ~ 2.152.09 2.12 ~.15 2.16 tg~ 2.622.5~ ~.58 2.62 2.65 tgg 95 ~.143.88 ~.02 4.14 ~.22 Degrees 10 o~ 14 19 16 14 13 f reedom ~92;~

The data shown in Table IV reflect the amount of swelling control for various ratios of HTH/LiOH and HTH/Li2S04 ~ H20 .

TABLE IV
Amolmt of Swelling**
Mean SD* Number of Salt ~TH/Salt (mm) (mm) Obs~rvat_ons oH 9 9 . 9/ ~ 18~13 1.12 2 ~9/1 ~.26.24 2 9~/2 7.262.06 2 95/5 4.582.91 2 90/10 1.~6.76 7 80/20 5.301.91 3 ~0/30 6.~1.15 60/40 6.52.13 2 50/50 6.222.33 2 Li2SO4 H2O 99~9/ol 7.48 1.86 2 99/1 7.041.44 2 98/2 6.14.35 2 ~5/5 2.83.~8 2 90/10 5.172.21 80/20 2.40.12 2 70/30 1~99.~5 2 60/40 1.93.29 2 50/50 1.91.33 2 3Q/70 1.55.26 2 10~90 1.24.30 Z

*Standard deviation **80F/ambient humidity a~mosphere surrounding the test beaker The data shown in Table IVA reflec~ the t value with the larges~ amou~t of confidence possible less 'chan tcalc -. TABLE IVA
Degrees of ~ ~tcalc t90 ~95 ~97 5 tg9 tgg 95 Freedom Salt~ LiOH_ 98/2 ~26 1~36 12 g5/5 1~43 1~36* 1~78 12 90/10 7~53 1~33 1~7~ 2~ 57 3~97* 17 80/20 4~14 1~35 1~77 2~16 2~5* 4~22 13 70/30 1~21 1~36 12 60/4~ ~61 1~36 12 50/5Q .82 1.36 12 Salt: Li~ ~ -2 99 ~ g/~ 36 1~
9g/1 ~52 1~36 12 9~/2 2~04 1.36 1.78* 2~18 12 95~5 ~.87 1.36 1.78 2.1~ 2.6~ 4.32* 12 g0/10 2.18 1.34 1.75 2.12* 2.58 16 80/20 7~31 1~36 1~78 2~18 2~68 4~32* 12 70/3~ 7O70 1~36 1~78 2~18 2~8 4~32* 12 60/40 7~71 1~36 1~78 2~18 2~68 4~32* 12 50/507 o 65 ~ 36 1 ~ 78 2 ~ 18 2068 4 ~ 32* 12 30/70 8~2~ 36 1~78 2~18 2~6~ ~32* 12 10/~ l ``}`~36 107~ 2~ 68 4~32* 1 *The~t--value with the largest amount u confidence possible less than tcalC.

The data of Table V show that cakes "A" and "B" made of 100% HTH ~ or 87J11% HTH/~aCl swell and hung-up, respectively~ a~ter 6 and 21 days, while thP
"Cl' cakes made o HTH/Form 2 did not hang-up in the product compaxtment of the dispenserO

TABLE V
Cumulative Grams Av. C12 (Amount of ~v. Cl Dispensed Since Day 0) 2 _ .
A B C
587~ HTH* 100% HTH** 90% HTH***
~ NaCl 10~ Form 2*
Grams C~ Grams Cl Grams Cl Days Left pensed Left pensed Left pensed 0 51.4 - -51 ~-63.4 1 47.6 3.8 44.8 ~.260.6 2.8 6 38.013.4 44.0 7.049.4 14.0 38.712~7 - 40.9 22.5 21 35~915.5 35.8 27 D 6 : ; : 2~ - 33.6 29.8 Tablet DLmensions: :
*weight ~83 grams; length (height) ~7.62 cm;
width ~4O06 cm;: thickness ~1.52 cm ~:
~0 B: **weight ~77 ~rams; length (height~ -7.62 cm;
: width ~4.06 cm; thickness -1.52 cm C: ***weight:-100 grams; length (height) -7.62 cm;
width .4.06 cm; thickness ~1.78 cm Dispenser~Cake Compartmen~ DimensionsO
height -8/13 cm; width ~5O08 cm;
thickness -2.18 cm The first ~wo types o cakes, A and B, shown in Table V, a~ter 6~days of usage, were visually seen ~ as excessively~swolle~ and hanging up in tha compart ment. Thus, the 87~ HTH/ll~o NaCl (A) and the 100~ HTH
(B) type cakes stopped dispensing significan~ levels of Av. Cl~ after about 6 ~ays ~ecause the cakes stopped ~'3235~

gravity fe~ding in the dispenser. The "C" cakes, although initially ~hicker, continued to gravity feed because of controlled swelling.
Referring to Table VA, rectangular square cakes containing ratios of HTH ~ to Form 2 ~ from 95/5 to 5Q/S0 plus added NaCl at leveLs of from 0% to 50%
were tested for swelling control. The cakes wexe o~
the type shown in Fig~ 5 having an overall heigh~ of about 76 mm, a thickness of 18.8 mm and a width of 43 mm. Each cake was placed in 250 ml beakers each con-taining 53 ml of ambien~ waterO The water level on the cake was initially about 2 cm, which simulates the condi~ion of a cake in use in a "bot~om-feed" dispenser.
The amount o~ swelling (mm) a~ter a we~k for each cake is shown in Table VA. The data show ~hat, in genera~, the addition of NaCl to HTH/Form 2 compQsitiQns improves~
cake swelling control. In Table VA the amount of swell-ing (mm) i5 obtained by subtra~ting the sum o the initial cake width and thickness from the sum o~ the f;inal cake width and thickness.

TABLE VA
~mount of HTH/F2 NaCl Added to HTH/F2 Mixture Ratio 0% 1~ 50~*~
95/5 4.5 mm 4.0 mm 90/1~ ~4.5 mm 2~5 m~ 3.0 mm 70/30 3.0 mm 2~5 mm 2.0 mm 50/50 8.0 mm 3.5 mm 2~0 mm Swelling = Final (width ~ thickness) minus Initial (width + thickness).

3~'~

Referxing now to Figs. 1 and 2 in which identical f~atures are identically designated, Fig. 1.
shows a preferred bottom-feed dispensex 20. The dis-penser 20 contains a solid state calcium hypochlorite cake 21. Dispenser 20 compxises a front wall 22, a back wall 23, sidewall segments 25, Z6, 31, 50, 51 and 90, a top wall 28, bo~tom wall segments 29, 53 and 54, a~d interior partitions 32, 55, 56, 57, 58, 95 and 96, and cake support members 33. The cake support members 33 are of lesser thickness than the dispenser width to ensure th~t liquid can wash acxoss part of the tapered lowermo~t surfaces 21a and 21~ of cake 21 along its entire length. The walls and partitions are rigid and define a liquid solution reservoir 65 or a liquid solution, a cake compar~ment 69, a siphon tube ~4 having a second air trap 82 disposed adjacent thereo and having discharge reservoir 85, uppermost ~erticaL
passageway 86, a horizontal passageway 87, a ~ertical passag~way 88 connecting with inlet/discharge conduit 80, said inlet/discharge conduit having a first air trap 81 disposed adjacent thereto, and vent means for the reservoir comprising passageways 71 and 72 and air vent 83. The lowermost edge of partition segment 58 is designated 59, the lowermost edge of partition segment 96 is designated 67, ~he expos~d edge of bottom wall segment 29 is designated 61, the lowermost edse of level control partition 32 is designated 62, the upper-most edge of sidewall segment 31 is designated 93, and the low~rmost edge of sidewaIl segment 26, which in conjunction wi.th front and back walls 22 and 23, respec-tively, and sidewall segm~nt 31 define air vent 83, is designated 64. The inlet/discharge port of dispenser 20 located at the lowermost end of siphon tube 44 is designated 78~ The free spaces 68R and 68S around the cake 21 within cake comp~rtment 69 is designed to ~9;~3~

accommodate some cake swelliny upon initial contact with water 63. If the free space is too small, the cake 21 will hang up on ~ront wall 22, back wall 23, left side wall 25 and level control partition wall 32, and the chemicals will b~ wasted.
Referring to Fig. 1, it is impoxtant that the total of ~he ~ree space 68R between vertical rear and fron-t cake surfaces 21R and ront and rear walls 22 and 23, respectively, be a~ least from 0.4 cm to 2 cms, preferably, from 0.5 cm to 1.5 cm, about half in ront and hal~ i.n rear. I~ is also important that the total o~ the free space 68S between vertical side cake sur-faces 21S and side wall 25 and level control partition wall 32 be at least from 0.4 cm to 4 cms, preerably from 0~5 cm to 2 cms. Free spaces 68R and 68S axe needed for contro1Ied cake swelling. Insufficient free ~pace will result in the cake 21 hanging up on the vertical walls of the dispenser reservoir. Also, a minimum amount of free space 68T is needed between top cake surace 21T and top wall 28 for controlled cake swelling. Space 68T is preferably at leas~ from 0.1 cm to 1 cm, and more preferably at least from 0.1 cm.
Referring to Table V, it will be noted that the free space for each of the cakes A and B corres-ponding to 68R, i.e., the to~al free space be~weenvertical rear and f~ont walls and the corresponding vertical surfaces of each.cake was about 0.66 cm. The corresponding free space for cake C of the present in-vention was only 0.40 cm. Although less free space was allowed for cake C, i~ did not "hang up" in the cake CGmpartment.
The free sp~ces correspondin.g to 685 and 68T
were ~he same for the Table V cakes A, B and C~ 2.0 cms and 0.51 cm, respectively~

3~

Th~ depth of immersion, i.e., water exposed cake surface area of cake 21 is controlled by -the vertical distance "H" be~ween the uppermost surface of product support members 33 and lowenmost edge 62 of level control partition 32. The amount o~ in~erface between the cake and the liquid contained within the dispenser 20 con-trols the solid hypochlorite cake 21 dissolution rate. With dispenser embodiments of the type generally shown in Fig. 1 it has generally been found that the vertical distance "H" should be less than ~bout 1 cm, and most preferably less than about 0.5 cm.
A particularly preerred dispenser embodLment of the present invention (no-t shown) employs two shelf-like support members 33 such as present in Fig. 1secured to and projecting from back wall 23. A larger reservoir based on reservoir 65 can be made to be centrally positioned under two support mPmbers 33 to collect insoluble particles. ~ vertical distance "~I"
of about 10 mm between the uppermost surface of the support members and the lowermost edge of the level control partition can ~e employed.
The solid product in question initially can weigh about 60 grams and have a lowermost surface measuring 5 cm in length by about lo 27 cm in width.
Referring to Fig. 2, when the dispenser 20 containing a calci~m hypochlorite cake 21 is disposed, for instance, in a toilet tank (not shown) on a bracket or other mounting means (not shown) 50 ~hat the FULL
level o water 63 in the toilet tank is sufficiently high to a~ least reach edge 64 of sidewall segment 26, ~he dispenser will respond as the level o~ water drops from the FULL position in the toile~ t~nk when the toil~t is flushed and thereafter as the level Z3~

of wat~r in the toilet tank rises to the FULL position after completion of the ~lush cycle. The flush cycLe is ~ully shown a~d explained in said U.S. Pat. No.
4,208,747.
Referring to Fig. 2 it is apparent that res~rvoix 65 will retain a portion of the concentrated hypochlorite praduct solution 103 after the dispen6ing operation is completed. The hypochlorite solution 103 ~hus re~ained will be available to cover rapid multiple lG flushes Gf the toilet and preferably is larger than shown, and/or a secondary reservoir (not shown) can be designed in bottom wall 29. Secondary solution reser-voirs (not shown~ can be designed to collect insoluble cake by-produc~s (e.gO, CaCO3) of hypochlorite solution 103 in th~ lowermost portions of primary solution reservoir 65.
When the level of the toilet tank water 63 is in the FULL position, as illustrated in Fig. 2, the dispenser 20 will likewise be restored to thQ condition illustrated in Fig. 2 and will remain in that condition during the ensuing quiescent pexiod awaiting the next flush cycle of the toilet.
The dispens r embodiment 20 illustrated in Figs. 1 and 2 can discharge a predetermined quantity or dose~volume of hypochlorit~ product solution 103 from the dispenser each time the toilet is flushed. The dose-volume of solution is substantially equal to the quantity of solution contained within dispenser 20 between lowermost edge 62 of level con~rol partition 32 and lowermost edge 67 of partition segment 96 in addi-tion to the column of product solutio~ contain~d within passageway 71. The amount of hypochlorite product solution 103 that can be dispensed duriny each 1llsh cycle is more easily understood by comparing Fig. 2 which illustra-tes the condition o-f the dispensex 20 when the toile~ tank wate~ level 75 is F'ULL and air ~3~91Z3~;~

vent 83 has been blocked by the water, with Fig, 1, which illustrates the condition of an empty dispenser when the solution level within solution reservoir 65 would be at lowermost edge 67 of partition segrnent 96 and the dose-volume of solution has been released through inletfoutlet port 78.
The solid, water-soluble calcium hypochlorite cake 21 contained in cake compartment 69 will dissolve in the water introduced during each flush cycle to form the hypochlorite product solution 103 until such time as the solution becomes saturated or the toilet is again flushed. As the lower portions of the cake 21 are consumed by exposure to the liquid, the solid product will feed towards support members 33 and wall 29 within cake compartment 69. Because the volume and exposed surface area o~ cake 21 below edge 62 of level control par~ition wall 32 xemain essentially constant throughout the life of the cake, the strength or concen-~ tration of the hypochlorite solution 103 is particularly : 20 controlled throughout.the life o the dispenser 20, assuming an adequately long quiescent period for the solution to reach a normal concentration level is : provided intermediate the.flush cycles, i.e., a-bout 4 hours between flushes. It should be obvious that a shorter quiescen~ period will result in a hypochlorite solution 103 that will be correspondingly less concen-trated with les~ dissolved cake 21.
WhiIe the exemplary embodimen~ of dispenser 20, may be constructed by adhesively securing sections o relatively~ rigid Plexiglas (Registered Trademark of Rohm and ~aas Company) to one another, other relatively rigid materials which are subs~antially inert with respPct to the in~ended product and aqueous solutions t~ereof can be used to construct the dispensers.

3~

-- 2g --Furthermore, the dispensers may b0 constructed or formed at high speed and relatively low cosk utiliziny various manufac-turing techniques well known in the art.
For example, the dispensers could be vacuum thermofc~ned in two sections of a material such as polyvinyl chloride having an initial thickness of about 0.5 mm to 1 mm, the solid, water-soluble product inserted therebetween and the two sections thereafter secured to one another as by heat seaLing, adhesives~ etc.
The dispenser 20 in Fig. 1 is shown prior to the charging operation, i.e~, before it is immersed in toilet tank water 63 as shown in Fig. 2. In a flush cycle (not shown) the toilet tank water 63 rises, it enters siphon tube 44 and discharge reservoir 85 through i~let/discharge port 78. Air within the upper reaches ~f the siphon tube 44 is allowed to vent through discharge reservoir as, vertical passageway 86, horizontal passage-way 87, vertical passageway 88, inlet/discharge conduit 80, liquid solution re~ervoir 65, vent passageways 71 and 72 and ~ir vent 83. As the level of the toilet tank water 63 continues to rise, it begins to enter horizon-tal passageway 87~ Because the difference in elevation o the water in the ~oilet tank and the water within the siphon tube is rela~ively small prior to air vent 83 becoming blocked, the water head or water pressure available to force the wa~er in siphon tube 44 around the loop through vertical passageway 88 and into inlet/disch~rge condui~ 80 is likewise quite small. To minimize the required driving force to initiate water ~low through the loop, the dispenser 20 preferabl~
employs a series of passa~eways 86, g7 and 88, each o which is smalLer in cross~section than any portion of the one immediately preceding it~ thereby providing capillary suction in th~ direction o~ flow which tends to ~raw the water from the siphon tube 44 into the inlet/discharge conduit 80. It is of course recognized s~

that a maximum degree of capillaxy suction may be provided by employing passageways 86, 87 and 88 which are tapered and exhibit a continued reduction in cross-section in ~he direction o~ liquid flow during the dispenser charging operation. If desired, the entire length of the siphon tube 44 above the discharge reser-voir 85 may be convergent in the direction of water flow during the charging operation.
Once toilet tan~ water 63 enters inlet/
discharge conduit 80 and begins to collect in the solution reservoir 65, air is trapped in air trap 81 disposed adjacent inlet/dischar.ge conduit 80 (not shown). Namely, an air bubble i5 retained within the confines of the air trap 81 defined by partition seg-ments 55, 56, 57 and 58, which condition persists aslong as toilet tank water 63 continues to entex the dispenser 20.
Referrin~ again to Fig. 2, when the level 101 of incoming liquid within cake compartment 69 reaches lowermost edge 62 of level control partition 32, an air-lock is formed in the uppermost reaches of the cake chamber 69, thereby preven~i~g the liquid from rising fuxther within the cake compaxt~ent 69, It ~hould be noted that the liquid contacts only a lower surface area of solid product 21 up to a predetermined cake height "H" up to lowermost edge 62.
In the event the FU~L level of the toilet tank is below the aix vent 83, the level 102 of hypo~
chlorite product solu~io.n 103 in passageway 71 will be identical to the level 75 of the toilet tank water 63 surrounding the dispe~ser, while the level 101 of product solution 103 within cake compartmen~ 69 will be controlled by lowermost edge 62 of level conkrol parti-tion 32.
In ~he even~ level control partition 32 is eliminated and the FULL level of the toilet ~ank is :~9Z35~

below the air vent 83, ~he level of product solution 103 within the dispenser 20 will be iden~ical to the level 75 of toilet tank wa~er 63 surroundiny the dis-penser 20. In all cases, dispenser 20 will ~unction to isolate the resultant hypochlorite solution 103 con-tained in the upper reaches of cake compartment 69 from the surrounding toilet tank water 63, whether or not air vent 83 is blocked by ~oilet tank water. In the even~ air vent 83 is blocked by toilet tank water, isolation is provided by means of an air-lock created-in the upper reaches of passageway 72 in conjunction with the air-lock created in horizontal passagewa~ 87.
In the event air vent 83 is not blocked by toilet tank water, the vent to atmosphere provides the desired isolation from the toilet tank watex 63.
Referring again ~o Fig. 2, which represents the co.ndition o the dispenser 20 when the toile~ tank water level 75 is in its FULL position, the bulk o the air bubble retained within air ~rap 81 during the charging operation has rotated about edge 59 of parti-tion segment 58 so as to substantially fill hori~ontal passageway 87 as well as the uppermost portions of vertical passageways 86 and 88, there~y isolating the resultant liquid hypochlorite product solution 103 contained within the inlet~discharge conduit 80 from the toilet tank wa~er 63 contained within passageway 86 of siphon tube 44. The resultant hypochlorite pxoduct solution 103 contained within passageway 71, cake compartment 69, solution reservoir 65 and inlet/dis-charge conduit 80 is comple~ely isolated from toilet tank water by means of the air~lock provided in the uppermost sections of passageways 71 and 72 and the air-lock provided in the uppermost sec~ions of vertical passageways 86 and 88 and horizontal passageway 87.
As will be appreciated by ~hose skilled in the art, ~he ~oilet tank water 63 brough~ into contact with cake 21 during the charying operat.ion will continue to dissolve cake 21 at least until such time as the hypochlorite product solution 103 becomes saturated or until such time as the toilet is ~lushed and a predeter mined ~uantity or dose-volume of the liquid hypochlorite product solution 103 is available for dispensing and is either completely or partially discharged. As will also be appreciated by those skilled in the ar~, the exterior surfaces of cake 21 are pxPferably so config-ured as to permit a unifoxm delivery of hypochloritesolution 103 over the life of the calcium hypochlorite cake product 21. To this end, the exterior surfaces of the solid cake product 21 is preferably tapered at the bottom to ofset the effect of relatively high initial lS solubility of a fresh cake. Cake ~1 and the cakes of Figs. 3, 4 and 6 all show preferred tapered cakes.
Figs. 3 and 4 show the more preferred cakes.
Transfer of hypochlorite product solu-tisn 103 from the solution reservoir 65 into the discharge reservoir 85 to be discharged ~hrough the inlet/dis-charge port 78 continues until such time as the solution level in solution reservoir 65 reaches edge 67 o~
partition segment 96 (not shown), thereby venting siphon tube 44 and allowing the produc~ solution 103 contained therein to be released into the toilet tank wa~er 63.
The discharge reservoir 85 preferably com-prises an enlarged end of the siphon tube 44. The discharge reservoir 85 and i~s associated inlet/dis-3Q charge port or ports 78 can be sized to provide fordischarging of the hypochlorite solution 103 at almost any p~int in the flush cycle and a~ almos~ any rate of discharge.

~9~:~5~

~ 33 -The solid calcium hypochlorite ca~es of this invention do not form gels, but do form a small amoun~
of insoluble by-products, e.g., calcium carbonate~ So, dispensers having support members 33 are preferred to ensure that insoluble par~icles are washed away. The support members 33 posi~ioned in the lowermost portion of cake compartment 69 support cak~ 21 and are a level control mean~ ~o control the liquid level in contact with the cake 21. Said support members 33 also help to prevent the ins~luble particles from building up on and arou~d the hypochlorite cake~ The suppor~ members 33 also serve to control the area of contact between the liquid contained withirl the dispenser reservoir and cake 21.
So long as liquid is routed through thP
product cham~er during each ~lush cycle of ~he toilet, thP cake insoluble by-products will continue to be dispersed into the hypochlori~e liquid solution and which ultimately se~tles into the solution reservoir 65 located generally beneath th~ c~ke compartment 69.
Accordingly~ the tendency of the insolu~le cake by-products to build up on and around the cake is minimized.
With particularly preferred dispenser embodi-ments of the present invention, tha discharge of the 2S bulk of the liquid hypochlorite product solu~ion gener-ally occurs just before the completion of the f'ush cycle befoxe the toilet tank discharge outlet is closed and before tank refill beginsO
The dispenser disclosed herein is paxticu-larly well suited fox use with ot~er component products particularly if they are isolated from each o~her prior to use. ~ach dispenser se~ion of such a plural product dispenser will also maintain such a product CGmpOnent in isolation from the toilet tank water and simultaneou51y dispense the products when ~he toilet i5 flushed. Such plural product dispensing embodimen~s 35~

could be fabricated as a sin~le unit suspended i~ the toilet tank independently of one another, or interde-pendently suspended in the toilet tank b~ means o~ a common bracket or the like. Because the constant volume of solution dispensed duriny each flush cycle may readily be determined, it is thus possible to size such plural product dispensers so that each of the product compone~ts will be completely consumed at about the s~me point in time, thexeby minimizing ~aste of any particular component.
Referring now to Fig. 3, solid cake 221 illustrates a preferred hypochlorite bleach cake which exhibits s~mme~rical side tapers 221a and 221b. Cake 221 has a total height of 3 inches (7.62 mm) a taper height of 1.2 inches (30.5 mm), a top wid~h of about 1~55 inches (39.4 mm), a bottom ~idth of about 308 mm and the taper forms an angle of about 60 from the horizontal. The tapers 221a and 221b preferably form angles o~ from about 30 to about 65~ from the hori~on-tal, but is functional over a wid~r range. Cake thick-ness 223 is preferably 12 mm to 20 mm; cake width 224 is preferably 35 mm to 50 mm and the cake overall height 225 is prefexably about 70 mm to 85 mm. The cake taper height 226 of tapers 221a and 221b i5 prefer-rably about 25% ~o about 50% o the total cake height225, but is functional over a wider range.
Referring now t~ Fig. 4, another preferred cake 321 shows a rounded bot~om taper 322. This pre-ferred cake 321 has thickness, height and width geometry whioh is generally the same as that of cake 221, except for the geom~try of ~he ~aper 322. The rounded bottom taper 322 has an arc length 332a of about 30 mm. In preferred cakes of similar geometry, ~he arc of the rounded bottom may vary from about 20 mm to about 50 mm 3~

E'ig. 5 is a rectangular prism-shaped cake 421 with a square bottom Fig. 6 i.s a perspective view of a tapered cake 521 with one taper 522.
While particular embodiments of -the present invention have been illus~ra~ed and described, it will be obvious to those skilled in the art that various changes and modifi.cations can be made without departing from the spirit and scope of ~he invention and it is intended to cover, in the appended claims, all such modifications that are within the scope of this invention.

W~AT IS CLAIMED IS:

Claims (16)

Claims:

1. An article of manufacture comprising:
A. a dosing dispenser, and B. a calcium hypochlorite cake, said dosing dispenser comprising a reservoir having a cake compartment, means for allowing a dose volume of water to be routed through said reservoir with each dispensing cycle and means for immersing a lowermost portion of said cake to a predetermined depth in said water to facilitate dissolving a portion of said hypochlorite cake for dispensing at a later time, characterized in that said cake is substantially completely water-soluble and consisting essentially of:
I. an effective amount of a water-soluble lithium salt selected from the group consisting of:
lithium hypochlorite material, lithium hydroxide, lithium sulfate, lithium sulfate hydrate, and lithium chloride, and mixtures thereof; and II. from about 10% to about 98% of a substantially stable calcium hypochlorite material containing (i) from about 65% to about 78% calcium hypochlorite and (ii) a mixture of salts and other by-product materials normal to the manufacture of calcium hypochlorite; and wherein said cake is formulated such that swelling of said cake upon contact with said water is less than the swelling of a cake consisting essentially of said calcium hypochlorite material, said reservoir having vertical walls, said cake having vertical surfaces, said walls and corresponding cake surfaces having free space between them of at least 0.4 cm to 4 cm, and wherein said cake gradually dissolves and gravity feeds into said water with each cycle until the cake disappears.

2. The invention of Claim 1 wherein said cake is a composition comprising said calcium hypochlorite material, and said lithium hypochlorite material at a weight ration of 3:2 to 19.1.

3. The invention of claim 2 wherein said ratio is 3:2 to 9:1.

4. The invention of Claim 3 wherein said ratio is 9:1.

5. The invention of Claim 1 wherein said cake is a composition comprising said calcium hypochlorite material, and said lithium sulfate hydrate at a weight ratio of 1:9 to 49:1.

6. The invention of Claim 5 wherein said ratio is 1:9 to 19:1.

7. The invention of Claim 1 wherein said cake is a composition comprising said calcium hypochlorite material and said lithium hydroxide at a weight ratio of 4:1 to 19:1.

8. The invention of Claim 7 wherein said ratio is 4:1 to 9:1.

9. The invention of Claim 1, 2 or 3, wherein said cake is a composition comprising sodium chloride at a weight percentage of 1% to 50%.

10. The invention of Claim 1, 2 or 3, wherein said cake comprising sodium chloride at a weight percent of from about 5% to about 20%.

11. The invention of Claim 1, 2 or 3, wherein said calcium hypochlorite material is a composition comprising the following components, expressed in percentages by weight:
60.0 - 75.0 calcium hypochlorite 0.5 - 3.0 calcium chloride 004 - 4.0 calcium chlorate 1.5 - 5.0 calcium hydroxide 1.0 - 5.0 calcium carbonate 4.0 - 23.0 sodium chloride 0.4 - 8.5 water

12. The invention of claim 1, 2 or 3, wherein said calcium hypochlorite material is a composition comprising the following components, expressed in percentages by weight:

65-75 calcium hypochlorite 1.4 calcium chloride 0.9 calcium chloride 2.1 calcium hydroxide 1.3 calcium carbonate 21.3 sodium chloride 4.6 water.

13. The invention of Claim 1, 2 or 3, wherein said lithium hypochlorite material contains the following components, expressed in percentages of weight:
25-35 lithium hypochlorite 34 sodium chloride sodium sulfate & potassium sulfate 3 lithium chloride 1 lithium hydroxide 2 lithium carbonate 7 water.

14. The invention of Claim 1 wherein said free space is from 0.5 cm to 2 cm.

15. An article of manufacture comprising:
A. a dosing dispenser, and B. a calcium hypochlorite cake, said dosing dispenser comprising a reservoir having a cake compartment, means for allowing a dose volume of water to be routed through said reservoir with each dispensing cycle and means for immersing a lowermost portion of said cake to a predetermined depth in said water to facilitate dissolving a portion of said hypochlorite cake for dispensing at a later time, characterized in that said cake is substantially completely water-soluble and consisting essentially of:
I. lithium hypochlorite material; and II. from about 10 to 98% of a substantially stable calcium hypochlorite material containing (i) from about 65% to about 78% calcium hypochlorite and (ii) a mixture of salts and other by-product materials normal to the manufacture of calcium hypochlorite;
wherein said calcium hypochlorite material and said lithium hypochlorite material have a weight ratio of 3:2 to 19:1;
wherein swelling of said cake upon contact with said routed water is less than the swelling of a comparably sized cake consisting essentially of said calcium hypochlorite material, said reservoir having vertical walls, said cake having vertical surfaces and being positioned within said compartment such that the vertical surfaces of said cake are parallel to said vertical walls, said walls and corresponding cake surfaces having free space between them of at least 0.4 cm to 4 cm, and wherein said cake gradually dissolves and gravity feeds into said water with each cycle until the cake disappears.

16. An article of manufacture comprising:
A. a dosing dispenser, and B. a calcium hypochlorite cake, said dosing dispenser comprising a reservoir having a cake compartment, means for allowing a dose volume of water to be routed through said reservoir with each dispensing cycle and means for immersing a lowermost portion of said cake to a predetermined depth in said water to facilitate dissolving a portion of said hypochlorite cake for dispensing at a later time, characterized in that said cake is substantially completely water-soluble and consisting essentially of:
I. lithium sulfate hydrate material; and II. from about 10 to 98% of a substantially stable calcium hypochlorite material containing (i) from about 65% to about 78% calcium hypochlorite and (ii) a mixture of salts and other by-product materials normal to the manufacture of calcium hypochlorite;
wherein said calcium hypochlorite material and said lithium sulfate hydrate material have a weight ratio of 1:9 to 49:1;
wherein swelling of said cake upon contact with said routed water is less than the swelling of a comparably sized cake consisting essentially of said calcium hypochlorite material, said reservoir having vertical walls, said cake having vertical surfaces and being positioned within said compartment such that the vertical surfaces of said cake are parallel to said vertical walls, said walls and corresponding cake surfaces having free space between them of at least 0.4 cm to 4 cm, and wherein said cake gradually dissolves and gravity feeds into said water with each cycle until the cake disappears.