Receptacles – Stationary tank – For hot water heater or boiler
Reexamination Certificate
2000-03-16
2001-07-31
Moy, Joseph M. (Department: 3743)
Receptacles
Stationary tank
For hot water heater or boiler
C220S636000
Reexamination Certificate
active
06267261
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a hot water tank cavitated insulating support base which defines a containment channel to receive a lower edge portion of a plastic film wrapper in which is injected hot liquid urethane whereby to contain the liquid urethane in the lower portion of the bag when injected thereto to prevent the quickly expanding urethane from flowing out of the wrapper and out of the outer casing through crevices provided around pipe fittings or other areas of the outer shell.
BACKGROUND OF THE INVENTION
Description of Prior Art
Insulation support bases for hot water tanks are known. In my U.S. application Ser. No. 826,603 entitled “Insulating Support Base for a Cylindrical Electrical Hot Water Tank”, now U.S. Pat. No. 5,178,351 issued Jan. 12, 1993, I disclose the construction of an insulating support base formed of rigid insulating foam material whereby to support the bottom wall of the inner casing of a hot water tank and to facilitate centering of the outer casing thereabout. U.S. Pat. No. 5,180,077 also discloses a water heater bottom insulating disc wherein there is provided an upwardly convex center portion which mates with the concave base of the inner tank whereby to completely support the water heater and its water content. However, the center portion does not only support the inner tank, but at the same time, provides a better insulation than known prior art. These discs also permit centering of the inner casing and proper uniform spacing of the outer casing. Both these devices provide some thermal insulation to the base of the water heater.
In order to insulate the space between the inner casing side wall and the side wall of the outer casing, a sheet of insulating wool, such as Fiberglass® insulation, is usually folded over the entire inner casing from the top thereof and collapsed over the inner casing whereby to embrace the casing from both sides thereof. The insulating sheet may also be wrapped around the side wall of the water heater and a circular disc of insulation material placed on top of the heater. With these methods of insulation, it has been found that, in most cases, the insulating wool does not extend fully to the bottom of the casings and voids are created between the inner casing and outer casing adjacent the support disc spacing peripheral flange and elsewhere. Tests have shown that these voids in the side wall insulation results in heat loss in the tank bottom end and, therefore, energy inefficiency. By using expandable foam urethane much of the above disadvantages have been overcome. However, when using expandable urethane it is necessary to mask all crevices or holes in the outer casing and to introduce temporary plugs whereby to prevent expanded urethane to flow out of the outer casing or to obstruct areas where fittings need to be installed such as piping, etc.
Recently there was developed a need to recycle hot water tanks and at least the outer steel casing thereof. However, this was time consuming because the urethane foam had to be scrapped away from the inside wall of the inner casing. The use of plastic sheet wrappers was developed to solve this problem whereby the wrappers would protect the inside wall of the outer casing to prevent the expanded foam to adhere thereto. My U.S. Pat. No. 5,178,351, discusses such a wrapper and related prior art. The wrappers are formed of plastic film material and have one major disadvantage, that being that when the hot urethane is injected therein the wrapper bursts or melts due to the excessive heat of the liquid urethane which exceeds beyond the melting point of the wrapper and some of the urethane flange between the wrapper and the inner tank wall and between the wrapper and the outer casing at the base portion of the wrapper. As the foam quickly expands it quickly flows out of the outer casing through the gaps existing around the pipe fittings and the outer casing. Up to 50-60% of the material can escape through these gaps and when this happens the hot water tank is rendered unusable and needs to be recycled. This is very time consuming and costly.
It is also well known in the art that bacteria contamination of water in hot water heaters is susceptible in the lower end of the hot water heater where the temperature of the water is at its lowest. This phenomena is clearly described in Canadian Patent 2,030,976 issued on May 29, 1992 to Hydro Quebec and there is a brief description in that patent of the need to maintain the water temperature as high as possible in the lower tank region. However, this has proven difficult. It is therefore essential that the lower portion of the tank be properly insulated and this has been heretofore difficult to achieve due to the insulating methods utilized during the fabrication of hot water heaters. Reference is made to my Canadian Patent Application serial No. 2092348 published on Sep. 25, 1994 where I discuss this problem and present a solution but limited to the use of Fiberglass® wool
SUMMARY OF THE INVENTION
It is therefore a feature of the following to provide a cavitated insulating support base for a hot water tank which overcomes the above-mentioned disadvantages of the prior art.
Another feature of the present invention is to provide a hot water tank assembly including a cavitated insulating support base provided with a circumferential containment channel to receive the lower end portion of a plastic film or wrapper and a predetermined quantity of hot expandable liquid urethane placed in the wrapper in sufficient quantity to fill the space between the inner casing of the hot water heater and the outer shell thereof.
Another feature of the present invention is to provide a cavitated insulating support base for a hot water tank and wherein a circumferential containment channel is integrally formed therewith.
Another feature of the present invention is to provide a cavitated insulating support base for a hot water tank and wherein a containment channel is formed about an outer top preripheral portion of the support base by an outer circumferential flange which is spaced from the inner tank outer side wall.
According to the above features, from a broad aspect, the present invention provides a hot water tank is comprised of a cylindrical disc-shaped support base on which is supported a cylindrical inner tank concentrically therewith. A circumferential ridge projects upwardly adjacent an outer peripheral edge of the support base and spaced from a lower edge portion of a circumferential side wall of the inner tank to form a circumferential containment channel between the ridge and the lower edge portion. The channel has a volume sufficient to receive a lower portion of a plastic film pouch wrapper disposed at least about a lower section of the inner casing as well as a predetermined quantity of hot expandable liquid urethane placed therein in sufficient quantity to fill a space between the inner casing and an outer shell secured spaced about the inner casing when the urethane is expanded. The channel prevents the liquid urethane from flowing out of the lower portion of the wrapper located therein due to deterioration of the wrapper when exposed to the hot liquid urethane.
REFERENCES:
patent: 4860728 (1989-08-01), Nelson
patent: 4957097 (1990-09-01), Chevalier et al.
patent: 4972967 (1990-11-01), Nelson
patent: 5040697 (1991-08-01), Nelson
patent: 5178351 (1993-01-01), Lesage
Giant Factories Inc.
Houle Guy J.
Moy Joseph M.
Swabey Ogilvy Renault
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