TABLET OF A CHLORINE RELEASING SOLID COMPOUND
United States Patent 3856932
A tablet of chlorine releasing solid compound having substantially parallel plane faces in which the surfaces of the edge between the faces is sealed by water impervious and water insoluble material, which may be a continuous band of insoluble material which adheres to the compound, may be a band comprising a flexible sheet material attached to the edges of the tablet by a water insoluble adhesive, at least one of which is water impervious, or may have one of a number of alternative constructions comprising a self-adhesive tape, a coating of paint or synthetic resin, or a coating of wax. Alternatively the continuous band may be the side of a cup-like member and the tablet is sealed within the cup-like member by water impervious insoluble sealing material.
US Patent References:
/1144186.html
Freestone - June 1915 - 1144186
/1325361.html
Harshberger - December 1919 - 1325361
Poison-tablet
Davis - March 1920 - 1335488
Solution-identifying means for medicinal preparations
Thompson - October 1921 - 1393253
Package
Salfisberg - April 1922 - 1413064
/1144186.html
Freestone - June 1915 - 1144186
/1325361.html
Harshberger - December 1919 - 1325361
Poison-tablet
Davis - March 1920 - 1335488
Solution-identifying means for medicinal preparations
Thompson - October 1921 - 1393253
Package
Salfisberg - April 1922 - 1413064
Application Number:
05/885494
Publication Date:
12/24/1974
Filing Date:
12/16/1969
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
424/661, 422/37, D21/390, 252/175, 514/241, 252/176, 424/665, 252/187.100, 210/756, 206/524.600
International Classes:
B01F1/00; C02F1/76; B65D81/00; C02B3/08; A01N11/00
Field of Search:
424/16,149,249 252/90-94,134,174-176,187 210/62,64 206/.5,56,84 21/58
US Patent References:
| 1782526 | Tubular container | November 1930 | Beardsley | |
| 2051665 | Luminous label | August 1936 | West | |
| 2312381 | Medicinal tablet | March 1943 | Bickenheuser | |
| 2341583 | Luminescent or phosphorescent coating material | February 1944 | Tuve | |
| 2517513 | Pharmaceutical preparation for implantation | August 1950 | Vaernet | |
| 2519045 | Fumigant briquette | August 1950 | Houghton | |
| 3113076 | Medicinal tablets | December 1963 | Jacobs | |
| 3279995 | Shaped pellets | October 1966 | Reid | |
| 3342674 | Sterilizing, sanitizing, and/or disinfecting shapes | September 1967 | Kowalski | |
| 3488420 | CONTROLLED SOLUBILITY SANITIZER TABLET | January 1970 | Keast et al. |
Primary Examiner:
Rose, Shep K.
Attorney, Agent or Firm:
Weiner, Irving M.
Claims:
I claim
1. A tablet comprised of a chlorine releasing solid chemical compound for use as an agent for sanitizing water, said tablet having substantially parallel plane faces, the surface of the edge between said substantially parallel plane faces is sealed by a continuous band of a water impervious and water insoluble waterproof material, at least one of said substantially parallel plane faces being left completely exposed for chlorine release when placed in said water so that the surface area of said tablet exposed for chlorine release in said water remains constant for substantially the entire life of said tablet.
2. A tablet as claimed in claim 1 in which the tablet edge surface sealing material is a continuous band of insoluble material which adheres to the edge surface of the tablet.
3. A tablet as claimed in claim 2 in which the continuous sealing band comprises a flexible sheet material attached to the edge of the tablet by a water insoluble adhesive, at least one of which is water impervious.
4. In the art of chlorinating swimming pools by placing one or more chlorine releasing tablets in the pool whereby the contacting of the surface of the tablet with the water in the pool gives off chlorine over a period of time, until the tablet is completely dissolved, the chlorination process improvement comprising the step of providing an even daily supply of chlorine to the pool from start to finish by placing in the pool a swimming chlorinating tablet comprised of a chlorine releasing solid chemical compound as an essential water sanitizing agent and having substantially parallel plane faces completely exposed for chlorine release when placed in water, the surface of the edge between the exposed faces being sealed by a continuous band of a water impervious and water insoluble water proof material, the tablet being so constructed that the exposed surface of the tablet remains constant over substantially the entire life of the tablet.
5. A process as claimed in claim 4 in which the tablet edge surface sealing material of the tablet employed is a continuous band of insoluble material which adheres to the edge surface of the tablet.
6. A process as claimed in claim 5 in which the continuous sealing band of the tablet employed comprises a flexible sheet material attached to the edge of the tablet by a water insoluble adhesive, at least one of which is water impervious.
1. A tablet comprised of a chlorine releasing solid chemical compound for use as an agent for sanitizing water, said tablet having substantially parallel plane faces, the surface of the edge between said substantially parallel plane faces is sealed by a continuous band of a water impervious and water insoluble waterproof material, at least one of said substantially parallel plane faces being left completely exposed for chlorine release when placed in said water so that the surface area of said tablet exposed for chlorine release in said water remains constant for substantially the entire life of said tablet.
2. A tablet as claimed in claim 1 in which the tablet edge surface sealing material is a continuous band of insoluble material which adheres to the edge surface of the tablet.
3. A tablet as claimed in claim 2 in which the continuous sealing band comprises a flexible sheet material attached to the edge of the tablet by a water insoluble adhesive, at least one of which is water impervious.
4. In the art of chlorinating swimming pools by placing one or more chlorine releasing tablets in the pool whereby the contacting of the surface of the tablet with the water in the pool gives off chlorine over a period of time, until the tablet is completely dissolved, the chlorination process improvement comprising the step of providing an even daily supply of chlorine to the pool from start to finish by placing in the pool a swimming chlorinating tablet comprised of a chlorine releasing solid chemical compound as an essential water sanitizing agent and having substantially parallel plane faces completely exposed for chlorine release when placed in water, the surface of the edge between the exposed faces being sealed by a continuous band of a water impervious and water insoluble water proof material, the tablet being so constructed that the exposed surface of the tablet remains constant over substantially the entire life of the tablet.
5. A process as claimed in claim 4 in which the tablet edge surface sealing material of the tablet employed is a continuous band of insoluble material which adheres to the edge surface of the tablet.
6. A process as claimed in claim 5 in which the continuous sealing band of the tablet employed comprises a flexible sheet material attached to the edge of the tablet by a water insoluble adhesive, at least one of which is water impervious.
Description:
The invention relates to tablets of a chlorine releasing solid compound. These tablets are used extensively for the water treatment and sanitisation of swimming pools. See U.S. Pat. No. 3,342,674 for a partial listing of available species of solid compounds capable of releasing available chlorine when contacted with water, such as a chlorinated triazine compound, or an alkaline earth metal hypochlorite compound, and mixtures thereof. One or more tablets are placed in the pool, and the surface of the tablet coming into contact with the water gives off chlorine which sanitises the pool. This process continues over a period of time, in some cases as much as 14 days, until the tablet is completely dissolved.
The tablets are usually about 3 inches in diameter and approximately 1 inch thick, but they have the disadvantage that the amount of chlorine provided by the tablet varies in quantity over the period of time. When the tablet is placed in the water the surface area is at a maximum and it gives off a maximum amount of chlorine, but as the tablet dissolves it is reduced in size and as the surface area is also reduced so the quantity of chlorine given off is reduced proportionately. For instance, if the tablet dissolves completely in 14 days, and when first placed in the water maintains one part per million of chlorine in solution in the water, after seven days the surface area has been reduced by one-third, and the amount of chlorine given off is reduced proportionately, and maintains only two-thirds of a part per million, and from the start to the finish the supply of chlorine differs from day to day in a decreasing amount due to the reduction of the surface area.
The object of the present invention is to provide a tablet of the kind referred to which overcomes this drawback and provides an even, daily supply of chlorine to the pool from start to finish.
The invention consists in a tablet of chlorine releasing solid compound having substantially parallel plane faces at least one of which faces is left completely exposed, and said tablet being sealed around its edge by a continuous band of material which is insoluble in water.
The invention further consists in a tablet as set forth in the preceding paragraph in which the sealing material is a continuous band of insoluble material.
The invention still further consists in a tablet as set forth above in which the band is formed of a length of waterproof tape.
The invention still further consists in a tablet as set forth above in which the edge thereof is rendered water-resistant by a material sprayed thereon.
The accompanying drawing shows, by way of example only, one embodiment of the invention in which:
FIG. 1 is a perspective view of a known tablet of 3 inches diameter and 1 inch thick;
FIG. 2 is a perspective view of the same known tablet as shown in FIG. 1 after having been immersed in water for 7 days;
FIG. 3 shows a perspective view of a tablet constructed in accordance with the present invention,
FIG. 4 shows a perspective view of a tablet of FIG. 3 having been immersed in water for seven days, while
FIGS. 5, 6, 7 and 8 are cross sections of a tablet constructed in four different ways in accordance with the invention.
The tablet shown in FIG. 1 if 3 inches in diameter and 1 inch thick has a surface area of 231/2 sq. in. and the quantity of chlorine released in water is proportional to the surface area. If such a tablet is immersed in water for seven days it is reduced to the size shown in FIG. 2 in which it has a surface area of 141/2 sq. in. and the release of chlorine to the water has been reduced in proportion to the surface area of the tablet, as previously mentioned.
The tablet shown in FIG. 3 is of the same size as that shown in FIG. 1, but the edge is protected by a waterproof band or seal and the surface area exposed to the water is 15 sq. in. After such a tablet constructed in accordance with the invention has been left in the water for seven days the surface area still exposed to the water is the same as when first inserted, namely 15 sq. in. and in the release of chlorine to the water has remained constant over that period, and will continue to do so for substantially the whole life of the tablet.
In FIG. 5 the tablet of chlorine releasing solid compound 1 is housed in a cup-like member 2 by a water impervious and insoluble sealing material 3, which can conveniently be painted upon either or both the inner surfaces of this cup-like member at the edge and bottom of the tablet, and be of a rubbery nature, and the latter pressed into the former to seal both the edge and bottom against contact with the water in the swimming pool. The cup-like member may be constructed of a suitable insoluble material such as metal or plastics, or other rigid or semi-rigid material as required.
It is not essential that one of the faces of the tablet be sealed as in FIG. 5, and in consequence it is proposed in an alternative form of construction, as shown in FIGS. 6 and 7, to cover only the edge of the tablet by an impervious and water insoluble material. In FIG. 6 there is shown a rigid band of metal, plastic or other suitable material 4, in which the edge of the tablet is sealed within the ring by a sealing or adhesive compound 3. When lying on a horizontal surface in the water, the lower surface being covered, dispersion of the chlorine takes place principally from the exposed upper surface, and it acts in a similar manner to the construction of FIG. 5.
In the construction of FIG. 7 the sealing of the edge by a water impervious and water insoluble material can be carried out in a number of different ways. The water insoluble material 5 may be a band of flexible sheet material which is attached to the tablet by a water insoluble adhesive, at lest one of which is water impervious. For example, there may be applied to the tablet a self-adhesive tape, or the adhesive may be applied firstly to the edge of the tablet and the adhesive covered by a band, for example of aluminium foil, or vice versa.
In accordance with the construction of FIG. 7 the edge of the tablet may be sealed by a coating of liquid, which when dry adheres to the tablet, and forms a water insoluble and impervious seal 5. The liquid may be of a suitable paint, a synthetic resin, a natural or synthetic rubber, or it may be a coating of wax or other suitable material.
One face of the tablet may also be sealed as shown in FIG. 8 by one or other of the methods described in relation to FIG. 7, and may be the same or different from that applied to the edge of the tablet.
The layer of waterproofing does not have to be very thick, a thin coat is sufficient so long as it is just thick enough to seal the edge of the tablet against penetration of the water radially inwards, and adheres firmly to the granules face of the edge of the tablet during handling. The water must be prevented from obtaining access to the surface of the edge from the face of the tablet, under the sealing coating, and therefore it is essential that the latter should adhere firmly to the surface of the edge to prevent solution of the tablet inwardly from the edge.
If the sealing material is placed only upon the edge of the tablet, the tablets may be placed one upon another in a cylindrical form, and be sprayed together. The tablets may be used in that form, two or more together, to provide two or more times the period before replacement is required, or the tablets may be broken apart for use separately, immediately after the coating has dried, or when required for use, while other details to carry the invention into effect may be varied without departing from the scope of the invention claimed.
The tablets are usually about 3 inches in diameter and approximately 1 inch thick, but they have the disadvantage that the amount of chlorine provided by the tablet varies in quantity over the period of time. When the tablet is placed in the water the surface area is at a maximum and it gives off a maximum amount of chlorine, but as the tablet dissolves it is reduced in size and as the surface area is also reduced so the quantity of chlorine given off is reduced proportionately. For instance, if the tablet dissolves completely in 14 days, and when first placed in the water maintains one part per million of chlorine in solution in the water, after seven days the surface area has been reduced by one-third, and the amount of chlorine given off is reduced proportionately, and maintains only two-thirds of a part per million, and from the start to the finish the supply of chlorine differs from day to day in a decreasing amount due to the reduction of the surface area.
The object of the present invention is to provide a tablet of the kind referred to which overcomes this drawback and provides an even, daily supply of chlorine to the pool from start to finish.
The invention consists in a tablet of chlorine releasing solid compound having substantially parallel plane faces at least one of which faces is left completely exposed, and said tablet being sealed around its edge by a continuous band of material which is insoluble in water.
The invention further consists in a tablet as set forth in the preceding paragraph in which the sealing material is a continuous band of insoluble material.
The invention still further consists in a tablet as set forth above in which the band is formed of a length of waterproof tape.
The invention still further consists in a tablet as set forth above in which the edge thereof is rendered water-resistant by a material sprayed thereon.
The accompanying drawing shows, by way of example only, one embodiment of the invention in which:
FIG. 1 is a perspective view of a known tablet of 3 inches diameter and 1 inch thick;
FIG. 2 is a perspective view of the same known tablet as shown in FIG. 1 after having been immersed in water for 7 days;
FIG. 3 shows a perspective view of a tablet constructed in accordance with the present invention,
FIG. 4 shows a perspective view of a tablet of FIG. 3 having been immersed in water for seven days, while
FIGS. 5, 6, 7 and 8 are cross sections of a tablet constructed in four different ways in accordance with the invention.
The tablet shown in FIG. 1 if 3 inches in diameter and 1 inch thick has a surface area of 231/2 sq. in. and the quantity of chlorine released in water is proportional to the surface area. If such a tablet is immersed in water for seven days it is reduced to the size shown in FIG. 2 in which it has a surface area of 141/2 sq. in. and the release of chlorine to the water has been reduced in proportion to the surface area of the tablet, as previously mentioned.
The tablet shown in FIG. 3 is of the same size as that shown in FIG. 1, but the edge is protected by a waterproof band or seal and the surface area exposed to the water is 15 sq. in. After such a tablet constructed in accordance with the invention has been left in the water for seven days the surface area still exposed to the water is the same as when first inserted, namely 15 sq. in. and in the release of chlorine to the water has remained constant over that period, and will continue to do so for substantially the whole life of the tablet.
In FIG. 5 the tablet of chlorine releasing solid compound 1 is housed in a cup-like member 2 by a water impervious and insoluble sealing material 3, which can conveniently be painted upon either or both the inner surfaces of this cup-like member at the edge and bottom of the tablet, and be of a rubbery nature, and the latter pressed into the former to seal both the edge and bottom against contact with the water in the swimming pool. The cup-like member may be constructed of a suitable insoluble material such as metal or plastics, or other rigid or semi-rigid material as required.
It is not essential that one of the faces of the tablet be sealed as in FIG. 5, and in consequence it is proposed in an alternative form of construction, as shown in FIGS. 6 and 7, to cover only the edge of the tablet by an impervious and water insoluble material. In FIG. 6 there is shown a rigid band of metal, plastic or other suitable material 4, in which the edge of the tablet is sealed within the ring by a sealing or adhesive compound 3. When lying on a horizontal surface in the water, the lower surface being covered, dispersion of the chlorine takes place principally from the exposed upper surface, and it acts in a similar manner to the construction of FIG. 5.
In the construction of FIG. 7 the sealing of the edge by a water impervious and water insoluble material can be carried out in a number of different ways. The water insoluble material 5 may be a band of flexible sheet material which is attached to the tablet by a water insoluble adhesive, at lest one of which is water impervious. For example, there may be applied to the tablet a self-adhesive tape, or the adhesive may be applied firstly to the edge of the tablet and the adhesive covered by a band, for example of aluminium foil, or vice versa.
In accordance with the construction of FIG. 7 the edge of the tablet may be sealed by a coating of liquid, which when dry adheres to the tablet, and forms a water insoluble and impervious seal 5. The liquid may be of a suitable paint, a synthetic resin, a natural or synthetic rubber, or it may be a coating of wax or other suitable material.
One face of the tablet may also be sealed as shown in FIG. 8 by one or other of the methods described in relation to FIG. 7, and may be the same or different from that applied to the edge of the tablet.
The layer of waterproofing does not have to be very thick, a thin coat is sufficient so long as it is just thick enough to seal the edge of the tablet against penetration of the water radially inwards, and adheres firmly to the granules face of the edge of the tablet during handling. The water must be prevented from obtaining access to the surface of the edge from the face of the tablet, under the sealing coating, and therefore it is essential that the latter should adhere firmly to the surface of the edge to prevent solution of the tablet inwardly from the edge.
If the sealing material is placed only upon the edge of the tablet, the tablets may be placed one upon another in a cylindrical form, and be sprayed together. The tablets may be used in that form, two or more together, to provide two or more times the period before replacement is required, or the tablets may be broken apart for use separately, immediately after the coating has dried, or when required for use, while other details to carry the invention into effect may be varied without departing from the scope of the invention claimed.