HOT WATER TANK
United States Patent 3730144
A hot beverage dispenser is provided with an improved tank for storing water and for maintaining the water at the proper hot temperature. The tank is formed in a pair of separable components including a metallic bottom section and a transparent upper plastic section. An internal heating element is disposed within the bottom section together with an adjacent thermostatic control. The bottom metal tank section is insulated.
US Patent References:
Water-heater tank of reinforced plastic and method and apparatus for making the same
Noland et al. - September 1955 - 2718583
Hot water supply apparatus for a beverage dispensing machine
Maxwell - June 1965 - 3189225
Pressure vessel
Geitz - December 1965 - 3223492
LIQUID HANDLING AND DISPENSING APPARATUS
Knox, Jr. - February 1971 - 3565045
Water-heater tank of reinforced plastic and method and apparatus for making the same
Noland et al. - September 1955 - 2718583
Hot water supply apparatus for a beverage dispensing machine
Maxwell - June 1965 - 3189225
Pressure vessel
Geitz - December 1965 - 3223492
LIQUID HANDLING AND DISPENSING APPARATUS
Knox, Jr. - February 1971 - 3565045
Application Number:
05/227495
Publication Date:
05/01/1973
Filing Date:
02/17/1972
View Patent Images:
Export Citation:
Assignee:
Jet Spray Cooler, Inc. (Waltham, MA)
Primary Class:
Other Classes:
392/458, 392/451, 220/665, 392/441
International Classes:
A47J31/54; A47J31/44; F22B5/00
Field of Search:
122/13A,13R,14,19 126/361,362 220/82R
Primary Examiner:
Sprague, Kenneth W.
Claims:
Having thus described the invention what I desire to claim and secure by Letters Patent is
1. A hot water tank comprising:
2. A water tank as defined in claim 1 wherein said heat transfer means comprises heating means.
3. A water tank as defined in claim 1 wherein said upper tank section is formed from a transparent plastic thereby to enable the interior of said tank to be inspected without disassembly thereof.
4. A water tank as defined in claim 2 further comprising:
5. A water tank as defined in claim 1 further comprising:
6. A water tank as defined in claim 1 wherein said means connecting said upper and lower tank sections to each other comprises:
1. A hot water tank comprising:
2. A water tank as defined in claim 1 wherein said heat transfer means comprises heating means.
3. A water tank as defined in claim 1 wherein said upper tank section is formed from a transparent plastic thereby to enable the interior of said tank to be inspected without disassembly thereof.
4. A water tank as defined in claim 2 further comprising:
5. A water tank as defined in claim 1 further comprising:
6. A water tank as defined in claim 1 wherein said means connecting said upper and lower tank sections to each other comprises:
Description:
BACKGROUND OF THE INVENTION
This invention relates to improvements in water tank construction, and particularly to hot water tanks of the type used in dispensers for hot liquids such as hot chocolate and the like. For example, the hot water tank may be employed in dispensing apparatus of the type shown in U.S. Pat. No. 3,568,887 to Jacobs et al.
Typical prior hot water tanks as used in beveraged dispensers have been made from a non-corroding metal such as stainless steel, brass, copper or from porcelain lined tanks. In addition to the relatively high cost of material and manufacturing of such prior tanks, their use has not been free from difficulty. For example, all such tanks tend to develop scale formations on their inner surface resulting from the impurities in the water. Scale formation causes numerous problems which will be readily apparent to those familiar with the art. In the prior water tank construction, it is extremely difficult to clean effectively the inside of the tank to remove the built up scale. Access to the interior of the tank generally is extremely poor. Additionally, there is no way to easily and effectively inspect the interior of such prior tanks. As a result, the hot water tanks often would not be cleaned at all and would be used until the scale formation eventually caused failure of the tank to function properly, at which time the entire tank would be replaced, long before its possible use for life had expired.
The complete unitary metallic construction also tends to cause difficulties regarding the heating unit and control for operating the heating unit to maintain the water at the desired temperature. Prior tanks have employed either an internal heater which is permanently brazed into the tank or an external heater wrapped about the metallic tank to transmit heat to the water through the heat conductive tank wall. It was necessary to insulate fully the entire water tank with an appropriate surrounding insulative material. In those prior tanks which employ an internal heater, access to the heater element itself is relatively poor for the same reasons as is access to the inner surface of the tank for cleaning purposes. With the external heaters, the insulation required is considerably increased. In instances where the tanks may inadvertently empty itself, the response by the thermostatic control necessarily lags the temperature of the heater element. Repetitive "dry" operation of the heater element accellerates its oxidation and results in premature failure. It is among primary objects of the invention to provide an improved tank construction which avoids the foregoing difficulties.
SUMMARY OF THE INVENTION
In brief, my improved hot water tank is fabricated from a pair of separable sections including an upper plastic section and a lower metallic section. The upper plastic section is considerably longer than the lower metallic section so that the greater proportion of the tank is of the plastic construction. The top and bottom sections are detachably connectable so that the inner surfaces of both may be exposed fully for easy cleaning. Additionally, the upper plastic section preferably is transparent to permit inspection of the condition of the interior of the tank without disassembling any of the tank elements.
The tank includes an internal heater element mounted to and within the lower metallic section and a bimetallic thermostatic control is also mounted to the lower metallic section by means of a mount which extends into the tank, so that its bimetallic element is located in heat transfer proximity to the heater element. The heater and thermostatic control mount are disposed within the bottom section so that when the tank is disassembled the heater is readily exposed and easily accessible.
The tank also includes a specially formed seal between the mating plastic and metallic sections which also permits the different rates of expansion of the metal and plastic without disrupting the seal.
Among the objects of the invention is to provide an improved construction for a hot water tank for a hot beverage dispenser.
Another object of the invention is to provide a hot water tank in which the condition of the interior may be inspected readily and easily.
A further object of the invention is to provide a hot water tank which may be disassembled and cleaned easily.
Another object of the invention is to provide a hot water tank, a heating element and thermostatic control element which are arranged so that the thermostatic control may shut off the heater element promptly in the event that the tank runs dry.
Another object of the invention is to provide a hot water tank which requires relatively little supplemental insulation.
Still another object of the invention is to provide a hot water tank which is inexpensive to manufacture.
DESCRIPTION OF THE DRAWINGS
The foregoing and other objects and advantages of the invention will be understood more fully from the following detailed description thereof, with reference to the accompanying drawing in which
FIG. 1 shows a hot beverage dispenser employing the tank of the invention, with the tank being broken away to show its construction clearly.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The invention is illustrated as used in a hot beverage dispenser of the type shown in the aforementioned U.S. patent. As described more fully in that patent, the dispenser arrangement includes a housing 10, discharge nozzle 12 and a hood 14 which houses an arrangement for dispensing the beverage mix, such as hot chocolate, into a mixing device 16. Mounted rearwardly within the housing on a base 18 and appropriate bracket 20 is the hot water storage tank 22.
As described more fully below, the tank 22 is formed in two sections, an upper plastic section 24 and a lower metal section 26. Water is admitted into the tank through the lower section 26 by the fitting 28. The water is supplied to the machine through an inlet fitting 30 which directs the water to a needle valve flow control 32 through appropriate tubing and then from the flow control valve 32 through tubing 34 to the fitting 28. Valve means are located along this flow path to control operation of the device as described more fully in the aforementioned patent. The fitting 28 also includes a drain tube 36 to enable the entire tank to be drained if desired.
The upper end of the tank includes an outlet fitting which directs the heated water through the tubing 40 into the mixing device 16. The hot water is fed through the tube 40 as fresh water is introduced, in a measured volume, into the inlet of the tank through the fitting 28.
As described above, the upper section 24 of the tank is formed from an appropriate plastic suitable for use with hot water having a temperature normally approximating 180° F. The upper tank section 24 defines the substantially greater portion of the tank with the lower metallic section 26 defining a relatively small portion of the total tank volume. The upper tank section 24 preferably is transparent to enable the interior of the entire tank to be inspected without disassembling the tank. The upper tank section may be fabricated according to well known injection molding techniques to include a neck 42 at its upper end for fastening to the outlet fitting 38. The lower end of the upper tank section 24 is formed to define an outwardly extending circumferential flange 44. A circumferential groove is formed in the underside of the flange 44 to receive an O-ring seal 46 as described below.
The bottom section 26 of the tank is formed from a corrosion resistant metal such as stainless steel. The bottom section 26 is formed with an outwardly extending circumferential flange 48 which is adapted to mate abuttingly with the flange 44 on the upper tank section 24. The outer end of the flange 48 may be downturned as shown. The flanges are secured together by circumferentially spaced bolts 50. Preferably, a metal backing ring 52 surrounds the upper tank section 24 against the flange 44 to distribute the clamping force of the bolts 50 fully about the plastic flange 44. The O-ring 46 is disposed so that it bears firmly against the upwardly facing surface of the flange 48 of the lower tank section 26. From the foregoing it will be apparent that the interior of the tank may be inspected without disassembling any of the tank parts. If access to the interior of the tank is desired, as for cleaning scale deposits, the tank sections may be separated easily to expose the inner surfaces of the tank sections 24, 26 through the enlarged openings at their mating ends.
In the illustrative embodiment, the tank includes the electric resistance heater 54 mounted within the lower section 26. The heater 54 may be supported firmly in the lower section 26 by brazing it at the juncture of the heating element and the wall of the lower section 26. In the preferred embodiment, the heater 54 is contained, in its entirety, within the lower metallic section and does not extend into the plastic upper section 24 of the tank. This minimizes likelihood of excessive heat from the heater damaging the plastic upper section 24 in the event of heater malfunction.
In order to further reduce likelihood of damage to the heater 54 or any of the other elements of the tank in the event that the tank inadvertently runs "dry" with the heater continuing to operate, a bimetallic thermostat 56 is mounted to the lower tank section 26. The bimetallic thermostat 56 is mounted to the tank by a mount 58 secured to the tank. The mount 58 has a portion disposed interiorally of the tank in proximity to the heater 54 to receive heat and conduct heat to the bimetallic thermostatic element 56. The element 56 is in heat conductive relation to the mount 58. Heat is received by bimetallic thermostat both from the walls of tank section 26 and from the mount 58. The thermostat 56 may be selected from any of a number of commercially available devices in which the temperature sensitive bimetallic element may be mounted as described above. In the event that the tank did run dry, inadvertently, the excess heat developed by the heating coil 54 would be sensed in a relatively short time by the mount stem 58 so that the thermostatic control 56 may shut off the power to the coil 54. The heater 54 and bimetal thermostatic control device 56 preferably should be selected so that the heater 54 is shut off in no more than approximately 2 minutes of "dry" operation.
In order to insulate the tank and the hot water contained therein, only the lower section 26 need be provided with external, supplemental insulation. As shown in the drawing, an appropriate wall arrangement 60 formed from any of a number of readily available insulative materials surrounds the sidewall and bottom of the lower section 26. The upper tank section 24 is self insulative by reason of its plastic construction. For this purpose, the plastic material from which the upper section 24 is fabricated also should have satisfactory heat transfer characteristics. Selection of an appropriate plastic material is considered to be a matter of choice and the techniques for proper selection will be readily apparent to those skilled in the art.
It should be understood that the foregoing description of the invention is intended merely to be illustrative thereof and that other embodiments and modifications may be apparent to those skilled in the art without departing from its spirit.
This invention relates to improvements in water tank construction, and particularly to hot water tanks of the type used in dispensers for hot liquids such as hot chocolate and the like. For example, the hot water tank may be employed in dispensing apparatus of the type shown in U.S. Pat. No. 3,568,887 to Jacobs et al.
Typical prior hot water tanks as used in beveraged dispensers have been made from a non-corroding metal such as stainless steel, brass, copper or from porcelain lined tanks. In addition to the relatively high cost of material and manufacturing of such prior tanks, their use has not been free from difficulty. For example, all such tanks tend to develop scale formations on their inner surface resulting from the impurities in the water. Scale formation causes numerous problems which will be readily apparent to those familiar with the art. In the prior water tank construction, it is extremely difficult to clean effectively the inside of the tank to remove the built up scale. Access to the interior of the tank generally is extremely poor. Additionally, there is no way to easily and effectively inspect the interior of such prior tanks. As a result, the hot water tanks often would not be cleaned at all and would be used until the scale formation eventually caused failure of the tank to function properly, at which time the entire tank would be replaced, long before its possible use for life had expired.
The complete unitary metallic construction also tends to cause difficulties regarding the heating unit and control for operating the heating unit to maintain the water at the desired temperature. Prior tanks have employed either an internal heater which is permanently brazed into the tank or an external heater wrapped about the metallic tank to transmit heat to the water through the heat conductive tank wall. It was necessary to insulate fully the entire water tank with an appropriate surrounding insulative material. In those prior tanks which employ an internal heater, access to the heater element itself is relatively poor for the same reasons as is access to the inner surface of the tank for cleaning purposes. With the external heaters, the insulation required is considerably increased. In instances where the tanks may inadvertently empty itself, the response by the thermostatic control necessarily lags the temperature of the heater element. Repetitive "dry" operation of the heater element accellerates its oxidation and results in premature failure. It is among primary objects of the invention to provide an improved tank construction which avoids the foregoing difficulties.
SUMMARY OF THE INVENTION
In brief, my improved hot water tank is fabricated from a pair of separable sections including an upper plastic section and a lower metallic section. The upper plastic section is considerably longer than the lower metallic section so that the greater proportion of the tank is of the plastic construction. The top and bottom sections are detachably connectable so that the inner surfaces of both may be exposed fully for easy cleaning. Additionally, the upper plastic section preferably is transparent to permit inspection of the condition of the interior of the tank without disassembling any of the tank elements.
The tank includes an internal heater element mounted to and within the lower metallic section and a bimetallic thermostatic control is also mounted to the lower metallic section by means of a mount which extends into the tank, so that its bimetallic element is located in heat transfer proximity to the heater element. The heater and thermostatic control mount are disposed within the bottom section so that when the tank is disassembled the heater is readily exposed and easily accessible.
The tank also includes a specially formed seal between the mating plastic and metallic sections which also permits the different rates of expansion of the metal and plastic without disrupting the seal.
Among the objects of the invention is to provide an improved construction for a hot water tank for a hot beverage dispenser.
Another object of the invention is to provide a hot water tank in which the condition of the interior may be inspected readily and easily.
A further object of the invention is to provide a hot water tank which may be disassembled and cleaned easily.
Another object of the invention is to provide a hot water tank, a heating element and thermostatic control element which are arranged so that the thermostatic control may shut off the heater element promptly in the event that the tank runs dry.
Another object of the invention is to provide a hot water tank which requires relatively little supplemental insulation.
Still another object of the invention is to provide a hot water tank which is inexpensive to manufacture.
DESCRIPTION OF THE DRAWINGS
The foregoing and other objects and advantages of the invention will be understood more fully from the following detailed description thereof, with reference to the accompanying drawing in which
FIG. 1 shows a hot beverage dispenser employing the tank of the invention, with the tank being broken away to show its construction clearly.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The invention is illustrated as used in a hot beverage dispenser of the type shown in the aforementioned U.S. patent. As described more fully in that patent, the dispenser arrangement includes a housing 10, discharge nozzle 12 and a hood 14 which houses an arrangement for dispensing the beverage mix, such as hot chocolate, into a mixing device 16. Mounted rearwardly within the housing on a base 18 and appropriate bracket 20 is the hot water storage tank 22.
As described more fully below, the tank 22 is formed in two sections, an upper plastic section 24 and a lower metal section 26. Water is admitted into the tank through the lower section 26 by the fitting 28. The water is supplied to the machine through an inlet fitting 30 which directs the water to a needle valve flow control 32 through appropriate tubing and then from the flow control valve 32 through tubing 34 to the fitting 28. Valve means are located along this flow path to control operation of the device as described more fully in the aforementioned patent. The fitting 28 also includes a drain tube 36 to enable the entire tank to be drained if desired.
The upper end of the tank includes an outlet fitting which directs the heated water through the tubing 40 into the mixing device 16. The hot water is fed through the tube 40 as fresh water is introduced, in a measured volume, into the inlet of the tank through the fitting 28.
As described above, the upper section 24 of the tank is formed from an appropriate plastic suitable for use with hot water having a temperature normally approximating 180° F. The upper tank section 24 defines the substantially greater portion of the tank with the lower metallic section 26 defining a relatively small portion of the total tank volume. The upper tank section 24 preferably is transparent to enable the interior of the entire tank to be inspected without disassembling the tank. The upper tank section may be fabricated according to well known injection molding techniques to include a neck 42 at its upper end for fastening to the outlet fitting 38. The lower end of the upper tank section 24 is formed to define an outwardly extending circumferential flange 44. A circumferential groove is formed in the underside of the flange 44 to receive an O-ring seal 46 as described below.
The bottom section 26 of the tank is formed from a corrosion resistant metal such as stainless steel. The bottom section 26 is formed with an outwardly extending circumferential flange 48 which is adapted to mate abuttingly with the flange 44 on the upper tank section 24. The outer end of the flange 48 may be downturned as shown. The flanges are secured together by circumferentially spaced bolts 50. Preferably, a metal backing ring 52 surrounds the upper tank section 24 against the flange 44 to distribute the clamping force of the bolts 50 fully about the plastic flange 44. The O-ring 46 is disposed so that it bears firmly against the upwardly facing surface of the flange 48 of the lower tank section 26. From the foregoing it will be apparent that the interior of the tank may be inspected without disassembling any of the tank parts. If access to the interior of the tank is desired, as for cleaning scale deposits, the tank sections may be separated easily to expose the inner surfaces of the tank sections 24, 26 through the enlarged openings at their mating ends.
In the illustrative embodiment, the tank includes the electric resistance heater 54 mounted within the lower section 26. The heater 54 may be supported firmly in the lower section 26 by brazing it at the juncture of the heating element and the wall of the lower section 26. In the preferred embodiment, the heater 54 is contained, in its entirety, within the lower metallic section and does not extend into the plastic upper section 24 of the tank. This minimizes likelihood of excessive heat from the heater damaging the plastic upper section 24 in the event of heater malfunction.
In order to further reduce likelihood of damage to the heater 54 or any of the other elements of the tank in the event that the tank inadvertently runs "dry" with the heater continuing to operate, a bimetallic thermostat 56 is mounted to the lower tank section 26. The bimetallic thermostat 56 is mounted to the tank by a mount 58 secured to the tank. The mount 58 has a portion disposed interiorally of the tank in proximity to the heater 54 to receive heat and conduct heat to the bimetallic thermostatic element 56. The element 56 is in heat conductive relation to the mount 58. Heat is received by bimetallic thermostat both from the walls of tank section 26 and from the mount 58. The thermostat 56 may be selected from any of a number of commercially available devices in which the temperature sensitive bimetallic element may be mounted as described above. In the event that the tank did run dry, inadvertently, the excess heat developed by the heating coil 54 would be sensed in a relatively short time by the mount stem 58 so that the thermostatic control 56 may shut off the power to the coil 54. The heater 54 and bimetal thermostatic control device 56 preferably should be selected so that the heater 54 is shut off in no more than approximately 2 minutes of "dry" operation.
In order to insulate the tank and the hot water contained therein, only the lower section 26 need be provided with external, supplemental insulation. As shown in the drawing, an appropriate wall arrangement 60 formed from any of a number of readily available insulative materials surrounds the sidewall and bottom of the lower section 26. The upper tank section 24 is self insulative by reason of its plastic construction. For this purpose, the plastic material from which the upper section 24 is fabricated also should have satisfactory heat transfer characteristics. Selection of an appropriate plastic material is considered to be a matter of choice and the techniques for proper selection will be readily apparent to those skilled in the art.
It should be understood that the foregoing description of the invention is intended merely to be illustrative thereof and that other embodiments and modifications may be apparent to those skilled in the art without departing from its spirit.