CA1320875C - Hot water system with atmospheric gas burner - Google Patents
Hot water system with atmospheric gas burnerInfo
- Publication number
- CA1320875C CA1320875C CA000555987A CA555987A CA1320875C CA 1320875 C CA1320875 C CA 1320875C CA 000555987 A CA000555987 A CA 000555987A CA 555987 A CA555987 A CA 555987A CA 1320875 C CA1320875 C CA 1320875C
- Authority
- CA
- Canada
- Prior art keywords
- water
- pressure vessel
- heat exchanger
- fresh
- hot water
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Abstract
IMPROVED HOT WATER SYSTEM
WITH ATMOSPHERIC GAS BURNER
ABSTRACT OF THE DISCLOSURE
An improved hot water system using an atmospheric gas burner is provided. The system includes a pressure vessel for storing hot water to provide a ready supply of hot water for an end user. It also includes a heat exchanger comprising a tubular coil in communication with the pressure vessel and a fresh, cold water source.
Water flows from the pressure vessel or the fresh water source to the heat exchanger and, after heating, flows back into the bottom of the vessel. An atmospheric gas burner mounted proximate the pressure vessel extends into the bottom of the central opening of the heat exchanger coil to heat the water as it passes through the heat exchanger. Finally, the hot water system includes a pump for inducing flow of the water in the desired direction and a check valve which allows flow only in this direction and only flow of a predetermined force.
WITH ATMOSPHERIC GAS BURNER
ABSTRACT OF THE DISCLOSURE
An improved hot water system using an atmospheric gas burner is provided. The system includes a pressure vessel for storing hot water to provide a ready supply of hot water for an end user. It also includes a heat exchanger comprising a tubular coil in communication with the pressure vessel and a fresh, cold water source.
Water flows from the pressure vessel or the fresh water source to the heat exchanger and, after heating, flows back into the bottom of the vessel. An atmospheric gas burner mounted proximate the pressure vessel extends into the bottom of the central opening of the heat exchanger coil to heat the water as it passes through the heat exchanger. Finally, the hot water system includes a pump for inducing flow of the water in the desired direction and a check valve which allows flow only in this direction and only flow of a predetermined force.
Description
1 320~75 IMPROVED HOT WATER SYSTEM
~ACKGROUND OF T~E INVÆNTION
Eield Oe the Invention The present invention relates to an improved hot water system which uses an atmospheric gas burner Eor heating the water which it stores and supplies. More particularly, the invention relates to an improved gas burning hot water system which stores hot water and which heats the hot water by removing a portion of the water from a ~torage vessel, heating it and placing it back into the storage vessel.
Description of the Prior Art Prior art hot water systems which use atmospheric gas burners to heat water typically include a metal pressure vessel and a gas burner disposed beneath the vessel. In these systems, the burner heats the water by heating the bottom of the vessel. However, these systems suEfer a number of disadvantages. First, scale which forms on the inside surface of a metal pressure vessel as a result of heating or rusting accumulates at . :
-.
., . .
t 32n~75 the bottom of the vessel and forms a thick layer of sediment. This material acts as an insulator and prevents effective heating of the water.
Second, the inside surface of a metallic pressure vessel ruqts or corrodeq. To prevent such corrosion from occurring, the manufacturers of these metal vessels provlde a protection system in the inside of the vessel, including an anode rod. A by-product of this protection system i9 hydrogen gas. This ga~ presents a significant danger to the user of the hot water system, since its ignition may cause a destructive explosion.
Eliminating this problem increases the complexity and c03t of these~ prior metal vessels.
Third, the temperaturle of the water at the top of these prior metal tanks may ~iffer Çrom that at the bottom by as much as 40 to 50~. This diEferential occurs due to the Eollowing: The metal tanks typically receive water at the bottom where a the~mostat takes temperature readings. The thermostat initi~ltes heating every time the water temperature decreases below a predetermined level.
This usually occurs every time fresh, cold water enters the vessel at the bottom of the vessel. However, the water at the top of the vessel usually has a higher temperature. Moreover, although metal tank systems heat the water by heating the bottom of the tank, a portion of this heat transfers to a ~lue pipe which extends vertically through the center of the vessel and heats the water at both the top and bottom. Therefore, the repeated h~ating raises the water temperature at the top of the vessel. These conditions combine to raise the temperature of the water at the top of the vessel to as - . . - , high a level as 170F. Water at this temperature scalds the user of the water. Moreover, heating water in this manner wastes energy.
Recently, manufacturers of hot water systems have begun to market an increasing number of systems with thermoplastic, thin-walled pressure ve~sels. These pressure vessels have composite outer shells of continuously wound glass filaments impregnated with a thermose~tting resin material and inner liners made out of thermoplastic material. Their sidewalls are relatively thin and light making them easy to handle and construct.
Although these vessels have relatively thin sidewalls, the material~3 used to construct them are poor conductor~ of heat. Thus, a burner disposed c)utslde of the vessel cannot heat the water inside. In addition, placing a flame on the outside surface of these thin-walled pressure vessels damages them. Therefor~, it is not possible to use the standard gas heating sy~,tem with these new thin-walled thermoplastic tanks.
The improved hot wa~er sy~tem of the present invention avoids the disadvanta~es of the prior hot water systems which use metal pressure vessels and allows the use of thermoplastic pressure vessels with a gas heater system. The system of the present invention moves water from the bottom of the system pressure vessel or draws water directly from the fresh water source, heats the water at a heat exchanger disposed outside of the pressure vesQel and returns the heated water back into the bottom of the pressure vessel for storage. Moreover, the system .: :
':
-maintains the temperature of the stored water at arelatively constant temperature throughout the pressure vessel.
The improved hot water system of the present invention includes a thin-walled pressure vessel and a heat exchanger which receives water from the pressure vessel or a fresh water source and brings it into heat exchange relation with an atmospheric gas burner so that the water may receive the heat provided by the burner.
The system also includes conduit means defining passageways through which the water flows from the pressure vessel to the heat exchanger and back to the vessel and a pump for lnducing this Elow.
SUMMARX QF ~HE INVENTION
It is a generaI object of this invention to provide an improved hot water slystem which uses an atmospheric gas burner for heatlng the water which the ~ystem stores and supplies.
It i5 a more specific object of the present invention to provide an improved gas-fired hot water system which includes a thin thermoplastic pressure vessel for storing the water heated by the system; a heat exchanger coil and an atmospheric gas burner for heating a portion of the water outside of the vessel; and a conduit, check valve and pump arrangement for circulating the water for heating.
It is another object of this invention to provide an improved hot water system which heats and stores water by receiving water from a fresh, cold water .
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1 32087~
source or by removing a portion of water contained by the pressure vessel, heating it at a heat exchanger outside of the vessel and placing it in the vessel for storage.
Other objects, advantages and features of the present invention will become apparent upon reading the eollowing detailed description and appended claims, and upon reference to the accompanying drawings.
In the preferred embodiment of the present invention, an improved hot water system includes a pressure vessel di~posed in an insulated housing. The vessel, generally referred to as a plastic tank, is a cylindrical enclosure capable of containing various fluids at high pressures and temperatureq. In the preferred embodiment, the tank comprises a hollow shell having an elongate cylindrical body and substantially hemispherically shaped top and bottom portionq. But the vessel may have any other sultable shape or configuration.
The hollow shell includes an inner liner made of a suitable thermoplastlc materlal such as polybutylene.
The outer shell covers the innee llning and provides strength, rigidity and structural integrity to the vessel.
It is a composite material comprising glass Eilaments impregnated with a thermosetting resinous material.
However, this outer shell may be a metal structure, a combination of the composite and metallic materials, or any suitable material which provides strength, rigidity and structural integrity to the vessel without substantially increasing its size and weight.
Additionally, the inner liner may be made from any other suitable non-metallic material.
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1 32C)~75 The vessel includes a dip tube which lies in the vessel and extends from the top of the vessel down to the bottom. The bottom of this dip tube is closed except for a number of small openings. In the illustrated embodiment, a fitting disposed at the top of the vessel secures the dip tube in place and connects it with a Eresh water source. This fitting also connects the fresh water source and the dip tube to a conduit which provides a passageway to a heat exchanger.
The heat exchanger is a conduit formed into an elongated coil, providing an increased area for heat exchange. This coil or heat exchanger lies vertically in an insulated housing proximate the pressure vessel. It is made from metal or any other material having a hlgh thermal conductivity; and it has a frustoconlcal shape with a large bottom opening for receiving a vertically mounted atmospheric gas burner and a smaller top opening.
This conflguration allows the coil to trap the heat provided by the burner and acilltate heat transfer.
The atmospheric gas b~rner used with the system of the present invention has an elongate housing, and it lies vertically along the pressure vessel housing. It includes a tube having a dome-shaped inlet segment for receiving both fuel gas and air, an opposite, flaring end segment, and a constricted middle portion. This configuration produces a "venturi effect" i.e., suction at the inlet of the tube. In addition to the suction, the tube inlet has an enlarged size which allows the burner to receive an increased amount of air for efficient burning of the fuel gas.
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The burner also includes a barrel disposed in communication with the outlet opening of the inlet tube.
This barrel has a large number of ports which vent the air and fuel gas mixture which the burner receives. Upon ignition of this mixture , a thin, bluish and nonluminoius combustion layer forms around the burner. This combustion layer burns hot and raises the temperature of the barrel to a level at which it glows red hot and radiates infrared heat. The barrel extends into the heat exchanger housing and into the bottom portion of the central opening through the middle of the coil. There, it provides heat for heating the coil and the water which flows through it.
A conduit disposed between the heat exchanger and the pressure vessel providesl a ~luid passageway between the bottom o the heat e!xchanger and the vessel.
In breaks along this conduit, the system includes a pump which induces flow of the water through the dip tube, through the heat exchanger, and back into the vessel. It also includes a check valve which prevents the water from ~lowing in this direction without sufEicient pressure provided by either the pump or other means. This check valve also prevents the water from 10wing in the opposite direction, l.e., out of the pressure vessel through a port at the bottom of the vessel, upwardly through the heat exchanger and back into the pressure vessel through the dip tube. A thermostat disposed at the ~ottom of the pressure vessel takes temperature readings of the water at this location and initiates the heating cycles.
In operation, water flows from a fresh water source into the system through the fitting disposed at the top of the vessel. Since the dip tube openings at the ,, ..
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1 320~75 bottom of the pressure vessel are small, the water flows into the conduit connecting the heat exchanger with the pressure vessel, rather than into the bottom of the vessel through the dip tube. It then flows through the heat exchanger and into the bottom of the vessel through the port disposed at the bottom of the vessel. The line pressure of the fresh water is sufficient to overcome the resistance provided by the check valve. In response to the flow of cold water, the thermostat activates the 1~ burner and the pump. As more cold water flows into the system, the burner heats it as it passes through the heat exchanger.
Even though the system heats the fresh water before it flows into the pressure vessel, the temperature level of the body of water in tlle pressure vessel typically decreases below a desLred level. To raise the temperature level, the thermostat activates the pump and the burner so that the water at the bottom o~ the vessel flows into the dip tube, through the heat exchanger, and back into the vessel through the port at the bottom of the vessel.
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For a more complete understanding of this invention, one should now refer to the embodiment illustrated in greater detail in the accompanying drawings and described below by way of an example of the invention.
In the drawings:
I
1 320~75 Fig. 1 is a sectional view of the hot water system of the present invention, showing the overall structure and the conical heat exchanger coil.
Fig. 2 is a perspective view of the atmospheric gas burner used in the hot water system of the present invention.
Fig. 3 is a perspective view of the check valve used in the hot water system of the pre~ent invention.
While the following text describes the invention in connection with a preferred embodiment, one should understand that the invention is not limited to this embodiment. Furthermore, one should understand that the drawings are not necessarily to scale.
DETAILED DESCRIPTION OF T~E DRAWINGS
AND ~E PR~ERREI) EM~ODI~ENT
.
Turning now to the drawings, Fig. 1 shows the hot water system of the present invention generally at 11.
The system includes a plastic pressure vessel 13. This vessel 13 is a cylindrical plastic tank capable of containing various fluids at high pressures and temperatures. It comprises a hollow shell having an elongate cylindrical body and substantially hemispherically shaped top and bottom portions. But the vessel may have any other suitable shape or configuration.
The hollow shell includes an inner liner 15 made of thermoplastic material such as polybutylene. The vessel also includes an outer shell 17 which covers the inner liner 15 and provides strength, rigidity and ' ' ' . ', ,' , .': ' :
.. . . . .
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1 320~75 structural integrity to the vessel. This outer shell 17 is a composite material comprising glass filaments impregnated with a thermosetting resinous material.
However, it may be a metal structure, a combination of the S composite and metallic materials, or any suitable material which provides strength, rigidity, and structural integrity to the vessel without substantially increasing its size and weight. For insulation and further structural support, an insulated housing 19 fully enclQses the pressure vessel.
The pressure vessel includes a number o inlets and outlets as described in the following text. It has a port 21 at the bottom which serveq as a drain for the vessel 13. I~ also includes a port 23 through its top. A
lS fitting 25 disposed in this por~: 23 secures a dip tube 27 in place lnside the pressure vecisel.
This dip tube 27 exterlds from the fitting down to the bottom portion Oe the pressure vessel and has a constricted outlet. The dip tu~e 27 shown in ~ig. 1 has a closed bottom with a number of glmall side openings 29 which Eorm the constricted outlet. Alternatively, an open and pinched end may also provide a constricted outlet for the tube. The dip tube 27 is made from a corrosion resistant plastic or any other suitable material.
The fitting 25 connects the dip tube 27 with a fresh water source (not shown) from which the pressure vessel receives fresh, cold water. ït also connects a conduit 31 to the dip tube 27 and the fresh water source.
Although the illustrated embodiment shows a three-way fitting 25, other connecting devices and arrangements may provide the desired connection. For example, the vessel I 320~375 may have two ports at the top, one to provide com~unication between the vessel 13 and the conduit 31 and the other to provide communication between the vessel and a fresh water conduit.
This conduit 31 is a fluid passageway between the pressure vessel 13 and a heat exchanger 33. Like the dip tube 27, the conduit 31 may be made from a corrosion resistant plastic material or any other suitable material.
The heat exchanger 33 is a conduit formed into an elongate coil, providing an increased area for heat exchange. It lies vertically in an insulated heat exchanger housing 35. The heat exchanger coil 33 is made from any ~uitable metal, since metals are good conductors of heat. However, any other suitable mat~rial having a hLgh thermal conductivity may se!rve as an ade~uate ~ubstitute. In addition, the cc~il has a tubular and frustoconical oonfiguration with the 1argest diameter at the botto~. This configuration allows the coil to trap the heat provided by the system's burner and facilitate heat transfer to the water flowing through the coil.
Alternatively, any other suitable configuration, e.g., a cylindrical conEiguration with a constant diameter or one which defines a serpentine path with legs disposed longitudinally of the exchanger, provide the same function. The housing 35 has an opening 37 at the top through which the conduit 31 extends to communicate with the heat exchanger 33 and an opening 39 at the bottom through which an atmospheric gas burner 41 extends to heat the coil and the water which flows through it.
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The burner 41 lies vertically next to the insu1ated housing 19 which encloses the pressure vessel 13. The burner includes an inlet tube 43 and a barrel 45.
(See Fig. 2) The inlet tube 43 has a domed end segment, an opposite, flaring end segment and a con~tricted middle portion for producing a "venturi effect", ~, suction at the inlet of the tube. In addltion to the suction, the tube'q domed inlet has an enlarged size which allows the burner to receive an increased'amount of air for efficient burning of the fuel gas which Elows into the inlet tube 43 through a conduit 47. This conduit 47 extends into the inlet op~ening of the tube to supply the burner with euel gas. Sultable connectlng means ~not shown) mount the burner 41 to the hou91ng 19.
The barrel 45 extends thcough the opening 39 Oe the heat exchanger housing 35 and lnto the bottom of the coil's central opening 49. The heat rises through the central opening 49 of the coll and heats the remaining portion oE the coil whlch extends a ~ub~tantial dlstance '~0 above the burne~ barrel 45. The fuel ga~ and alr mixture which flows lnto the barrel 45 of the burner 41 vents through a plurality oE holes ~not shown) formed around the barrel. Upon ignition, small flames form at each one of these ports and they combine to form a combustion layer around the barrel. This combustion layer emits heat which heats the bottom end of the heat exchanger coil 33 and also heats the barrel 45, raising its temperature to a point at which the barrel glows red and emits infrared heat which further increas~es t~he heat productlon of the 30 burner ~1. Co-pending Canadian Application Serial ~-555,989- of ~.N. Jackson , entitled "Improved . .
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1 320~75 l3 Atmospheric Gas Burner', and assigned to the assignee of the present application, discloses the burner 41 in greater detail.
A conduit 51 forms a passageway between the bottom end of the heater coil 33 and the bottom of the pressure vessel 13.
Along breaks in this conduit, the system includes a check valve 53 and a pump 55. As shown in Fig. 3, the check valve 53 includes a houslng 57 which defines a chamber in communication with opposite ends of the break in the condult 51. It lncludes a float (not shown) whlch rlses and enters a seat at the inlet of the housing, sealing the chamber and preventing water from flowing downward when the system 11 does not receive iresh, cold water or when the pump 55 does not operate. Thus, the check valve 53 prevents cold water ln the coil from flowlng downward and lnduclng warm water ln the tank from flo~lng out of the vesse] 13 into the coil 33 where it could cool wlthout the burner 41 operatlng. In preventing such flow from developing the check valve 53 greatly lmproves the ef~iclency of the system.
The float also prevents water from flowlng upward at all times.
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A thermostat 65 disposed at the bottom of the pressure vessel takes temperature readings of the water at the bottom of the vessel. It communicates with the water through the port 63 and it act~tes the burner 41 and the pump 55 when the temperature o the water decreased below a predetermined level. `
In operation, water flows from a resh water source into the system 13 through the fitting 25 disposed through the top of the vesse:l 13. Since the dip tube openings 29 at the bottom of the pressure vessel are small, the water flows into the conduit 31 connecting the heat exc:hanger 33 with the pressure vessel 13 rather than into th~ bottom of the vessel. It then flo~s through the coil 33 and into the bottom of the vessel through the port 63. The llne pressure of the ~resh water is sufficient to move the float in the check valve away from its seat at the inlet o~ the housing 57. In response to the flow of cold water into the system, the thermostat activates the burner 41 and the pump 55. As Inore cold water flows into the system, the burner 41 heats it as it passes through the heat exchanger 33. Thus, the system heats the water before it even enters the pressure vessel.
Even though the system heats the fresh water before it allows it to flow into the pressure vessel, the temperature level of the body of water in the pressure vessel typically decreases below a desired level. To raise the temperature level, the thermostat 65 activates the pump 55 and the burner 41 so that the water at the bottom of the vessel 13 flows into the dip tube 27, through the conduit 31, through the heat exchanger 33 and back into the vessel through the conduit 51. The system .
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continues to move the stored water in this manner until the water rises to a predetermined temperature level.
Every time the temperature of the water decreases below this level, the system initiates this process.
S Thus, the applicant has provided an improved hot water system whlch uses an atmospheric gas burner to heat water. The 3ystem includes a pressure vessel in communication with a heat exchanqer disposed outside of the vessel. Water flows from the vessel to the heat exchanger where an atmospheric gas burner heats it. The heated water then flow3 back into the pressure vessel whlch store3 it until the user draws it out.
Whlle the applicant ha3 shown one embodiment oE
the lnventlon, one wlll understand, o~ course, that the lnventlon is not llmlted to this embodiment ~;ince those skilled in the art to whlch the invention pertains may make modi~icatlons and other embodiments of the principles of this invention, particularly upon considering the Eoregoing teachings. The applicant thereEore by the appended clalms, intends to cover any such modieications and embodlment3 as incorporate those features which constitute the essential features of this invention.
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~ACKGROUND OF T~E INVÆNTION
Eield Oe the Invention The present invention relates to an improved hot water system which uses an atmospheric gas burner Eor heating the water which it stores and supplies. More particularly, the invention relates to an improved gas burning hot water system which stores hot water and which heats the hot water by removing a portion of the water from a ~torage vessel, heating it and placing it back into the storage vessel.
Description of the Prior Art Prior art hot water systems which use atmospheric gas burners to heat water typically include a metal pressure vessel and a gas burner disposed beneath the vessel. In these systems, the burner heats the water by heating the bottom of the vessel. However, these systems suEfer a number of disadvantages. First, scale which forms on the inside surface of a metal pressure vessel as a result of heating or rusting accumulates at . :
-.
., . .
t 32n~75 the bottom of the vessel and forms a thick layer of sediment. This material acts as an insulator and prevents effective heating of the water.
Second, the inside surface of a metallic pressure vessel ruqts or corrodeq. To prevent such corrosion from occurring, the manufacturers of these metal vessels provlde a protection system in the inside of the vessel, including an anode rod. A by-product of this protection system i9 hydrogen gas. This ga~ presents a significant danger to the user of the hot water system, since its ignition may cause a destructive explosion.
Eliminating this problem increases the complexity and c03t of these~ prior metal vessels.
Third, the temperaturle of the water at the top of these prior metal tanks may ~iffer Çrom that at the bottom by as much as 40 to 50~. This diEferential occurs due to the Eollowing: The metal tanks typically receive water at the bottom where a the~mostat takes temperature readings. The thermostat initi~ltes heating every time the water temperature decreases below a predetermined level.
This usually occurs every time fresh, cold water enters the vessel at the bottom of the vessel. However, the water at the top of the vessel usually has a higher temperature. Moreover, although metal tank systems heat the water by heating the bottom of the tank, a portion of this heat transfers to a ~lue pipe which extends vertically through the center of the vessel and heats the water at both the top and bottom. Therefore, the repeated h~ating raises the water temperature at the top of the vessel. These conditions combine to raise the temperature of the water at the top of the vessel to as - . . - , high a level as 170F. Water at this temperature scalds the user of the water. Moreover, heating water in this manner wastes energy.
Recently, manufacturers of hot water systems have begun to market an increasing number of systems with thermoplastic, thin-walled pressure ve~sels. These pressure vessels have composite outer shells of continuously wound glass filaments impregnated with a thermose~tting resin material and inner liners made out of thermoplastic material. Their sidewalls are relatively thin and light making them easy to handle and construct.
Although these vessels have relatively thin sidewalls, the material~3 used to construct them are poor conductor~ of heat. Thus, a burner disposed c)utslde of the vessel cannot heat the water inside. In addition, placing a flame on the outside surface of these thin-walled pressure vessels damages them. Therefor~, it is not possible to use the standard gas heating sy~,tem with these new thin-walled thermoplastic tanks.
The improved hot wa~er sy~tem of the present invention avoids the disadvanta~es of the prior hot water systems which use metal pressure vessels and allows the use of thermoplastic pressure vessels with a gas heater system. The system of the present invention moves water from the bottom of the system pressure vessel or draws water directly from the fresh water source, heats the water at a heat exchanger disposed outside of the pressure vesQel and returns the heated water back into the bottom of the pressure vessel for storage. Moreover, the system .: :
':
-maintains the temperature of the stored water at arelatively constant temperature throughout the pressure vessel.
The improved hot water system of the present invention includes a thin-walled pressure vessel and a heat exchanger which receives water from the pressure vessel or a fresh water source and brings it into heat exchange relation with an atmospheric gas burner so that the water may receive the heat provided by the burner.
The system also includes conduit means defining passageways through which the water flows from the pressure vessel to the heat exchanger and back to the vessel and a pump for lnducing this Elow.
SUMMARX QF ~HE INVENTION
It is a generaI object of this invention to provide an improved hot water slystem which uses an atmospheric gas burner for heatlng the water which the ~ystem stores and supplies.
It i5 a more specific object of the present invention to provide an improved gas-fired hot water system which includes a thin thermoplastic pressure vessel for storing the water heated by the system; a heat exchanger coil and an atmospheric gas burner for heating a portion of the water outside of the vessel; and a conduit, check valve and pump arrangement for circulating the water for heating.
It is another object of this invention to provide an improved hot water system which heats and stores water by receiving water from a fresh, cold water .
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1 32087~
source or by removing a portion of water contained by the pressure vessel, heating it at a heat exchanger outside of the vessel and placing it in the vessel for storage.
Other objects, advantages and features of the present invention will become apparent upon reading the eollowing detailed description and appended claims, and upon reference to the accompanying drawings.
In the preferred embodiment of the present invention, an improved hot water system includes a pressure vessel di~posed in an insulated housing. The vessel, generally referred to as a plastic tank, is a cylindrical enclosure capable of containing various fluids at high pressures and temperatureq. In the preferred embodiment, the tank comprises a hollow shell having an elongate cylindrical body and substantially hemispherically shaped top and bottom portionq. But the vessel may have any other sultable shape or configuration.
The hollow shell includes an inner liner made of a suitable thermoplastlc materlal such as polybutylene.
The outer shell covers the innee llning and provides strength, rigidity and structural integrity to the vessel.
It is a composite material comprising glass Eilaments impregnated with a thermosetting resinous material.
However, this outer shell may be a metal structure, a combination of the composite and metallic materials, or any suitable material which provides strength, rigidity and structural integrity to the vessel without substantially increasing its size and weight.
Additionally, the inner liner may be made from any other suitable non-metallic material.
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1 32C)~75 The vessel includes a dip tube which lies in the vessel and extends from the top of the vessel down to the bottom. The bottom of this dip tube is closed except for a number of small openings. In the illustrated embodiment, a fitting disposed at the top of the vessel secures the dip tube in place and connects it with a Eresh water source. This fitting also connects the fresh water source and the dip tube to a conduit which provides a passageway to a heat exchanger.
The heat exchanger is a conduit formed into an elongated coil, providing an increased area for heat exchange. This coil or heat exchanger lies vertically in an insulated housing proximate the pressure vessel. It is made from metal or any other material having a hlgh thermal conductivity; and it has a frustoconlcal shape with a large bottom opening for receiving a vertically mounted atmospheric gas burner and a smaller top opening.
This conflguration allows the coil to trap the heat provided by the burner and acilltate heat transfer.
The atmospheric gas b~rner used with the system of the present invention has an elongate housing, and it lies vertically along the pressure vessel housing. It includes a tube having a dome-shaped inlet segment for receiving both fuel gas and air, an opposite, flaring end segment, and a constricted middle portion. This configuration produces a "venturi effect" i.e., suction at the inlet of the tube. In addition to the suction, the tube inlet has an enlarged size which allows the burner to receive an increased amount of air for efficient burning of the fuel gas.
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The burner also includes a barrel disposed in communication with the outlet opening of the inlet tube.
This barrel has a large number of ports which vent the air and fuel gas mixture which the burner receives. Upon ignition of this mixture , a thin, bluish and nonluminoius combustion layer forms around the burner. This combustion layer burns hot and raises the temperature of the barrel to a level at which it glows red hot and radiates infrared heat. The barrel extends into the heat exchanger housing and into the bottom portion of the central opening through the middle of the coil. There, it provides heat for heating the coil and the water which flows through it.
A conduit disposed between the heat exchanger and the pressure vessel providesl a ~luid passageway between the bottom o the heat e!xchanger and the vessel.
In breaks along this conduit, the system includes a pump which induces flow of the water through the dip tube, through the heat exchanger, and back into the vessel. It also includes a check valve which prevents the water from ~lowing in this direction without sufEicient pressure provided by either the pump or other means. This check valve also prevents the water from 10wing in the opposite direction, l.e., out of the pressure vessel through a port at the bottom of the vessel, upwardly through the heat exchanger and back into the pressure vessel through the dip tube. A thermostat disposed at the ~ottom of the pressure vessel takes temperature readings of the water at this location and initiates the heating cycles.
In operation, water flows from a fresh water source into the system through the fitting disposed at the top of the vessel. Since the dip tube openings at the ,, ..
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-- ' ~: .
1 320~75 bottom of the pressure vessel are small, the water flows into the conduit connecting the heat exchanger with the pressure vessel, rather than into the bottom of the vessel through the dip tube. It then flows through the heat exchanger and into the bottom of the vessel through the port disposed at the bottom of the vessel. The line pressure of the fresh water is sufficient to overcome the resistance provided by the check valve. In response to the flow of cold water, the thermostat activates the 1~ burner and the pump. As more cold water flows into the system, the burner heats it as it passes through the heat exchanger.
Even though the system heats the fresh water before it flows into the pressure vessel, the temperature level of the body of water in tlle pressure vessel typically decreases below a desLred level. To raise the temperature level, the thermostat activates the pump and the burner so that the water at the bottom o~ the vessel flows into the dip tube, through the heat exchanger, and back into the vessel through the port at the bottom of the vessel.
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For a more complete understanding of this invention, one should now refer to the embodiment illustrated in greater detail in the accompanying drawings and described below by way of an example of the invention.
In the drawings:
I
1 320~75 Fig. 1 is a sectional view of the hot water system of the present invention, showing the overall structure and the conical heat exchanger coil.
Fig. 2 is a perspective view of the atmospheric gas burner used in the hot water system of the present invention.
Fig. 3 is a perspective view of the check valve used in the hot water system of the pre~ent invention.
While the following text describes the invention in connection with a preferred embodiment, one should understand that the invention is not limited to this embodiment. Furthermore, one should understand that the drawings are not necessarily to scale.
DETAILED DESCRIPTION OF T~E DRAWINGS
AND ~E PR~ERREI) EM~ODI~ENT
.
Turning now to the drawings, Fig. 1 shows the hot water system of the present invention generally at 11.
The system includes a plastic pressure vessel 13. This vessel 13 is a cylindrical plastic tank capable of containing various fluids at high pressures and temperatures. It comprises a hollow shell having an elongate cylindrical body and substantially hemispherically shaped top and bottom portions. But the vessel may have any other suitable shape or configuration.
The hollow shell includes an inner liner 15 made of thermoplastic material such as polybutylene. The vessel also includes an outer shell 17 which covers the inner liner 15 and provides strength, rigidity and ' ' ' . ', ,' , .': ' :
.. . . . .
' ~ ' ' : -: '' -- .- , '. , ~
1 320~75 structural integrity to the vessel. This outer shell 17 is a composite material comprising glass filaments impregnated with a thermosetting resinous material.
However, it may be a metal structure, a combination of the S composite and metallic materials, or any suitable material which provides strength, rigidity, and structural integrity to the vessel without substantially increasing its size and weight. For insulation and further structural support, an insulated housing 19 fully enclQses the pressure vessel.
The pressure vessel includes a number o inlets and outlets as described in the following text. It has a port 21 at the bottom which serveq as a drain for the vessel 13. I~ also includes a port 23 through its top. A
lS fitting 25 disposed in this por~: 23 secures a dip tube 27 in place lnside the pressure vecisel.
This dip tube 27 exterlds from the fitting down to the bottom portion Oe the pressure vessel and has a constricted outlet. The dip tu~e 27 shown in ~ig. 1 has a closed bottom with a number of glmall side openings 29 which Eorm the constricted outlet. Alternatively, an open and pinched end may also provide a constricted outlet for the tube. The dip tube 27 is made from a corrosion resistant plastic or any other suitable material.
The fitting 25 connects the dip tube 27 with a fresh water source (not shown) from which the pressure vessel receives fresh, cold water. ït also connects a conduit 31 to the dip tube 27 and the fresh water source.
Although the illustrated embodiment shows a three-way fitting 25, other connecting devices and arrangements may provide the desired connection. For example, the vessel I 320~375 may have two ports at the top, one to provide com~unication between the vessel 13 and the conduit 31 and the other to provide communication between the vessel and a fresh water conduit.
This conduit 31 is a fluid passageway between the pressure vessel 13 and a heat exchanger 33. Like the dip tube 27, the conduit 31 may be made from a corrosion resistant plastic material or any other suitable material.
The heat exchanger 33 is a conduit formed into an elongate coil, providing an increased area for heat exchange. It lies vertically in an insulated heat exchanger housing 35. The heat exchanger coil 33 is made from any ~uitable metal, since metals are good conductors of heat. However, any other suitable mat~rial having a hLgh thermal conductivity may se!rve as an ade~uate ~ubstitute. In addition, the cc~il has a tubular and frustoconical oonfiguration with the 1argest diameter at the botto~. This configuration allows the coil to trap the heat provided by the system's burner and facilitate heat transfer to the water flowing through the coil.
Alternatively, any other suitable configuration, e.g., a cylindrical conEiguration with a constant diameter or one which defines a serpentine path with legs disposed longitudinally of the exchanger, provide the same function. The housing 35 has an opening 37 at the top through which the conduit 31 extends to communicate with the heat exchanger 33 and an opening 39 at the bottom through which an atmospheric gas burner 41 extends to heat the coil and the water which flows through it.
.
.
The burner 41 lies vertically next to the insu1ated housing 19 which encloses the pressure vessel 13. The burner includes an inlet tube 43 and a barrel 45.
(See Fig. 2) The inlet tube 43 has a domed end segment, an opposite, flaring end segment and a con~tricted middle portion for producing a "venturi effect", ~, suction at the inlet of the tube. In addltion to the suction, the tube'q domed inlet has an enlarged size which allows the burner to receive an increased'amount of air for efficient burning of the fuel gas which Elows into the inlet tube 43 through a conduit 47. This conduit 47 extends into the inlet op~ening of the tube to supply the burner with euel gas. Sultable connectlng means ~not shown) mount the burner 41 to the hou91ng 19.
The barrel 45 extends thcough the opening 39 Oe the heat exchanger housing 35 and lnto the bottom of the coil's central opening 49. The heat rises through the central opening 49 of the coll and heats the remaining portion oE the coil whlch extends a ~ub~tantial dlstance '~0 above the burne~ barrel 45. The fuel ga~ and alr mixture which flows lnto the barrel 45 of the burner 41 vents through a plurality oE holes ~not shown) formed around the barrel. Upon ignition, small flames form at each one of these ports and they combine to form a combustion layer around the barrel. This combustion layer emits heat which heats the bottom end of the heat exchanger coil 33 and also heats the barrel 45, raising its temperature to a point at which the barrel glows red and emits infrared heat which further increas~es t~he heat productlon of the 30 burner ~1. Co-pending Canadian Application Serial ~-555,989- of ~.N. Jackson , entitled "Improved . .
~: . .
, .
1 320~75 l3 Atmospheric Gas Burner', and assigned to the assignee of the present application, discloses the burner 41 in greater detail.
A conduit 51 forms a passageway between the bottom end of the heater coil 33 and the bottom of the pressure vessel 13.
Along breaks in this conduit, the system includes a check valve 53 and a pump 55. As shown in Fig. 3, the check valve 53 includes a houslng 57 which defines a chamber in communication with opposite ends of the break in the condult 51. It lncludes a float (not shown) whlch rlses and enters a seat at the inlet of the housing, sealing the chamber and preventing water from flowing downward when the system 11 does not receive iresh, cold water or when the pump 55 does not operate. Thus, the check valve 53 prevents cold water ln the coil from flowlng downward and lnduclng warm water ln the tank from flo~lng out of the vesse] 13 into the coil 33 where it could cool wlthout the burner 41 operatlng. In preventing such flow from developing the check valve 53 greatly lmproves the ef~iclency of the system.
The float also prevents water from flowlng upward at all times.
:
. :
~, . .
A thermostat 65 disposed at the bottom of the pressure vessel takes temperature readings of the water at the bottom of the vessel. It communicates with the water through the port 63 and it act~tes the burner 41 and the pump 55 when the temperature o the water decreased below a predetermined level. `
In operation, water flows from a resh water source into the system 13 through the fitting 25 disposed through the top of the vesse:l 13. Since the dip tube openings 29 at the bottom of the pressure vessel are small, the water flows into the conduit 31 connecting the heat exc:hanger 33 with the pressure vessel 13 rather than into th~ bottom of the vessel. It then flo~s through the coil 33 and into the bottom of the vessel through the port 63. The llne pressure of the ~resh water is sufficient to move the float in the check valve away from its seat at the inlet o~ the housing 57. In response to the flow of cold water into the system, the thermostat activates the burner 41 and the pump 55. As Inore cold water flows into the system, the burner 41 heats it as it passes through the heat exchanger 33. Thus, the system heats the water before it even enters the pressure vessel.
Even though the system heats the fresh water before it allows it to flow into the pressure vessel, the temperature level of the body of water in the pressure vessel typically decreases below a desired level. To raise the temperature level, the thermostat 65 activates the pump 55 and the burner 41 so that the water at the bottom of the vessel 13 flows into the dip tube 27, through the conduit 31, through the heat exchanger 33 and back into the vessel through the conduit 51. The system .
., , -. : : :
. . - . ~ . ~ , , .
continues to move the stored water in this manner until the water rises to a predetermined temperature level.
Every time the temperature of the water decreases below this level, the system initiates this process.
S Thus, the applicant has provided an improved hot water system whlch uses an atmospheric gas burner to heat water. The 3ystem includes a pressure vessel in communication with a heat exchanqer disposed outside of the vessel. Water flows from the vessel to the heat exchanger where an atmospheric gas burner heats it. The heated water then flow3 back into the pressure vessel whlch store3 it until the user draws it out.
Whlle the applicant ha3 shown one embodiment oE
the lnventlon, one wlll understand, o~ course, that the lnventlon is not llmlted to this embodiment ~;ince those skilled in the art to whlch the invention pertains may make modi~icatlons and other embodiments of the principles of this invention, particularly upon considering the Eoregoing teachings. The applicant thereEore by the appended clalms, intends to cover any such modieications and embodlment3 as incorporate those features which constitute the essential features of this invention.
~.~
Claims (7)
1. A gas-fired hot water system for heating water stored in said system or fresh, cold water which the system receives from a fresh water source and for storing the heated water, said system comprising:
a pressure vessel for containing hot water;
heat exchanger means having an inlet and an outlet, said heat exchanger means disposed proximate said pressure vessel for heating fresh, cold water or the water contained by the pressure vessel;
first conduit means defining a passageway between said inlet of said heat exchanger means and said fresh water source, and between said pressure vessel and said fresh water source;
an atmospheric gas burner disposed proximate said heat exchanger means in heat transfer relation with said heat exchanger means for heating the water passing through said heat exchanger means;
second conduit means defining a passageway from said outlet of said heat exchanger means to said pressure vessel; and pumping means in said second conduit means for pumping water through said first conduit means, said heat exchanger, and said second conduit means, into said pressure vessel.
a pressure vessel for containing hot water;
heat exchanger means having an inlet and an outlet, said heat exchanger means disposed proximate said pressure vessel for heating fresh, cold water or the water contained by the pressure vessel;
first conduit means defining a passageway between said inlet of said heat exchanger means and said fresh water source, and between said pressure vessel and said fresh water source;
an atmospheric gas burner disposed proximate said heat exchanger means in heat transfer relation with said heat exchanger means for heating the water passing through said heat exchanger means;
second conduit means defining a passageway from said outlet of said heat exchanger means to said pressure vessel; and pumping means in said second conduit means for pumping water through said first conduit means, said heat exchanger, and said second conduit means, into said pressure vessel.
2. The hot water system of claim 1, wherein said heat exchanger means is a conduit formed into a frustoconical coil.
3. The hot water system of claim 2, further comprising a first insulated housing for receiving therein said pressure vessel and a second insulated housing for receiving therein said heat exchanger means, said first and \
second insulated housing preventing heat from escaping from said pressure vessel and said heat exchanger.
second insulated housing preventing heat from escaping from said pressure vessel and said heat exchanger.
4. The hot water system of claim 1, further comprising a check valve disposed between said heat exchanger means and said pressure vessel in said second conduit means, said check valve only allowing flow inducted by said pump means and flow from said fresh, cold water source through said first conduit to said heat exchanger means.
5. A gas fired hot water system for heating fresh, cold water which the system receives from a fresh water source, for storing the heated water, and for recirculating and reheating the stored, heated water, said system comprising:
a thin-walled thermoplastic pressure vessel having top and bottom portions for containing hot water;
heat exchanger means having an inlet and an outlet disposed proximate said pressure vessel for preheating fresh, cold water before it enters said pressure vessel and for reheating the water contained by the pressure vessel when it falls below n predetermined temperature level;
first conduit means defining a passageway between said inlet of said heat exchanger means and said fresh water source, and between said bottom portion of said pressure vessel and said fresh water source;
an atmospheric gas burner disposed proximate said heat exchanger means and in heat transfer relation with said heat exchanger means for heating the water passing through said heat exchanger means;
said conduit means defining a passageway from said outlet of said heat exchanger means to said bottom portion of said pressure vessel; and thermostatically activated pumping means in said second conduit means for inducing flow from said fresh water source or said bottom portion of said pressure vessel through said first conduit means to said heat exchanger, through said heat exchanger to said second conduit means, through said second conduit means, and into said bottom portion of said pressure vessel.
a thin-walled thermoplastic pressure vessel having top and bottom portions for containing hot water;
heat exchanger means having an inlet and an outlet disposed proximate said pressure vessel for preheating fresh, cold water before it enters said pressure vessel and for reheating the water contained by the pressure vessel when it falls below n predetermined temperature level;
first conduit means defining a passageway between said inlet of said heat exchanger means and said fresh water source, and between said bottom portion of said pressure vessel and said fresh water source;
an atmospheric gas burner disposed proximate said heat exchanger means and in heat transfer relation with said heat exchanger means for heating the water passing through said heat exchanger means;
said conduit means defining a passageway from said outlet of said heat exchanger means to said bottom portion of said pressure vessel; and thermostatically activated pumping means in said second conduit means for inducing flow from said fresh water source or said bottom portion of said pressure vessel through said first conduit means to said heat exchanger, through said heat exchanger to said second conduit means, through said second conduit means, and into said bottom portion of said pressure vessel.
6. A method for maintaining a stored body of water at an elevated temperature level wherein some or all of the stored body of water at the elevated temperature level may be removed and be replaced by water at a lower temperature level, said method comprising the steps of:
(a) storing a body of water in a thin-walled thermoplastic pressure vessel having a top and a bottom portion;
(b) continuously monitoring the temperature level of the stored body of water at the bottom portion of the pressure vessel;
(c) replacing water removed from said pressure vessel with an equivalent volume of preheated water added at the bottom portion of the pressure vessel at a temperature level below the elevated temperature level;
(d) removing a portion of the water at the bottom portion of the pressure vessel which is at a temperature level below the elevated temperature level;
(e) heating said portion of water;
(f) placing said portion of water back into the bottom portion of the pressure vessel; and (g) repeating steps (d) through (f) until the entire body of water reaches the elevated temperature level.
(a) storing a body of water in a thin-walled thermoplastic pressure vessel having a top and a bottom portion;
(b) continuously monitoring the temperature level of the stored body of water at the bottom portion of the pressure vessel;
(c) replacing water removed from said pressure vessel with an equivalent volume of preheated water added at the bottom portion of the pressure vessel at a temperature level below the elevated temperature level;
(d) removing a portion of the water at the bottom portion of the pressure vessel which is at a temperature level below the elevated temperature level;
(e) heating said portion of water;
(f) placing said portion of water back into the bottom portion of the pressure vessel; and (g) repeating steps (d) through (f) until the entire body of water reaches the elevated temperature level.
7. The hot water system of claim 1, wherein said pressure vessel is formed with thin thermoplastic walls.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US180887A | 1987-01-08 | 1987-01-08 | |
| US001,808 | 1987-01-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1320875C true CA1320875C (en) | 1993-08-03 |
Family
ID=21697929
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000555987A Expired - Lifetime CA1320875C (en) | 1987-01-08 | 1988-01-07 | Hot water system with atmospheric gas burner |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1320875C (en) |
-
1988
- 1988-01-07 CA CA000555987A patent/CA1320875C/en not_active Expired - Lifetime
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