EP1017957A1 - Hot water heater with separator structure - Google Patents
Hot water heater with separator structureInfo
- Publication number
- EP1017957A1 EP1017957A1 EP97935296A EP97935296A EP1017957A1 EP 1017957 A1 EP1017957 A1 EP 1017957A1 EP 97935296 A EP97935296 A EP 97935296A EP 97935296 A EP97935296 A EP 97935296A EP 1017957 A1 EP1017957 A1 EP 1017957A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- chamber
- tank
- wall
- water
- intermediate chamber
- 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.)
- Withdrawn
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
- F24H1/18—Water-storage heaters
- F24H1/20—Water-storage heaters with immersed heating elements, e.g. electric elements or furnace tubes
- F24H1/205—Water-storage heaters with immersed heating elements, e.g. electric elements or furnace tubes with furnace tubes
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H9/00—Details
- F24H9/0005—Details for water heaters
- F24H9/001—Guiding means
- F24H9/0015—Guiding means in water channels
Definitions
- top and bottom walls are segments of spheres, for greater structural
- a separator structure 30 is received in the tank between the heating pipe 20
- the intermediate chamber has an
- the volume of the air "bubble" in the top of the intermediate chamber is determined on the basis of the "displacement" of water that occurs when hot water is
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Heat-Pump Type And Storage Water Heaters (AREA)
Abstract
A hot water heater comprises a tank (10) having top and bottom walls (104, 10b) and a peripheral wall (108) having an axis, the tank being adapted to contain water at a predetermined pressure above atmospheric pressure. A separator structure (30) is received in the tank (10) between the axis and the peripheral wall (10p) and is configured to separate the tank (10) into an inner chamber (32) surrounding the axis, an outer chamber (34) adjacent the perimeter wall, an intermediate chamber (36) between the inner and outer chambers, and a top chamber (38) adjacent the top wall and above the intermediate chamber. The chambers are in communication for flow of water along a supply path from the outer chamber (34), through the top chamber (38), through the inner chamber (32) and into the intermediate chamber (36) which has an upper closed portion for trapping a volume of gas above a level of water in the tank. A heat source (18) is provided for heating the water in the inner chamber (32).
Description
Hot Water Heater With Separator Structure
Background of the Invention
Hot water heaters that are heated by a fossil fuel (e.g., natural gas, propane gas
and oil) have a heating pipe that passes through the water storage tank and conducts
hot combustion gases from the fuel burner to a vent pipe. As the hot gases pass
through the heating pipe, which usually has baffles, fins and other elements to
enhance heat exchange from the gases to the pipe and from the pipe to the water, heat
is transferred to the water to heat it. Some of the heat content of the gas flowing
through the heating pipe is lost to the vent pipe. When the burner is off, most hot
water heaters are still vented to carry off the gases of a pilot burner, and loss of heat
by transfer from the water in the tank through the heating pipe to the flow of gases
through the heating pipe to the vent pipe exceeds all other standby heat losses. The
combination of losses when the burner is on and standby losses (burner off) through
the outer walls of the storage tank and through the heating pipe to the vent result in a
relative low efficiency for all fossil-fueled hot water heaters.
Summary of the invention
An obj ect of the present invention is to provide a hot water heater in which
heat losses, particularly standby losses, are significantly reduced, as compared with
previously known fossil-fueled hot water heaters. A further object is to enable the
improved efficiency to be obtained without unduly increasing the cost of
manufacturing the hot water heater. Still another object is to provide a tank
configuration for a hot water heater that can be used to advantage with an electrical
heat source, such as an immersed electric heating element.
The foregoing objects are attained, in accordance with the present invention,
by a hot water heater comprising a tank having top and bottom walls and a peripheral
wall having an axis, the tank being adapted to contain water at a predetermined
pressure above atmospheric pressure. A separator structure is received in the tank
between the axis and the peripheral wall and is configured to separate the tank into an
inner chamber surrounding the axis, an outer chamber adjacent the perimeter wall, an
intermediate chamber between the inner and outer chambers, and a top chamber
adjacent the top wall and above the intermediate chamber. The chambers are in
communication for flow of water along a supply path from the outer chamber, through
the top chamber, through the inner chamber and into the intermediate chamber, and a
reverse flow path opposite to the supply path. The intermediate chamber has an upper
closed portion for trapping a mass of gas above a level of water in the tank. A heat
source is provided for heating the water in the inner chamber. An inlet conduit leads
from outside the tank into the outer chamber, and an outlet conduit leads from the
intermediate chamber to outside the tank.
When hot water is drawn from the tank through the outlet conduit, cold water
from a supply is conducted into the tank through the inlet conduit. The cold water
flows through the supply path, that is, through the outer chamber, the top chamber and
the intermediate chamber, and finally enters the intermediate chamber, which is the
main storage reservoir for holding hot water in the tank. Soon after the cold supply
water begins to flow though the inner chamber, the burner or other heat source for the
tank is turned on. The supply water receives some heat from the intermediate
chamber and top chamber as it flows toward the inner chamber. The supply water is
further heated by heat transfer from the heat source as it flows through the inner
chamber. Inasmuch as the water flowing past the heat source in the inner chamber is
relatively cool, heat is transferred efficiently from the heat source to the water,
thereby extracting more heat from the heat source and reducing losses to the vent pipe in the case of a fossil-fueled unit.
When the outflow of water from the tank ceases, the heat source will remain on and supply heat for a period of time and restore the tank to a full demand heat
level. The water in the inner chamber heats rapidly to a very high temperature and
produces a reverse flow in the flow path formed by the separator structure. In
particular, gases (air and water vapor) trapped in the top of the intermediate chamber
become highly heated, thereby causing the trapped gas to expand in volume.
Inasmuch as the tank remains open to the supply through the supply conduit (but is
closed to the delivery), the expanding gas displaces water from the tank into the
supply line. As the very hot water from the inner chamber flows through the top and outer chambers, it gives up some of its heat to the gas and water in the intermediate
chamber and some to the peripheral wall of the tank. Water that is displaced from the
tank into the supply line also gives up heat by losses from the supply line.
When the heat source shuts off, the heated gases in the top of the intermediate
chamber cool relatively rapidly. The gas volume is reduced correspondingly, thus
allowing relatively cool water from the supply to flow into the tank along the supply
path. By designing the tank so that the displacement volume of the gas trapped in the
top of the intermediate chamber exceeds the combined volumes of the outer chamber,
top chamber, and inner chamber, all of the water in the outer chamber, top chamber of
inner chamber is replaced by relatively cool water from the supply. In that way, the
intermediate chamber is isolated by layers of cool water contained in the inner, top
and outer chambers. The cool water in the outer chamber reduces heat loss from the
water in the intermediate chamber through the perimeter wall of the tank; the cool
water in the upper chamber reduces heat loss from the water in the intermediate
chamber through the top wall of the tank; and the cool water in the inner chamber
reduces heat loss from the water in the intermediate chamber through the heating pipe
in the case of fossil-fueled hot water heaters. Accordingly, the main sources of
standby losses are reduced significantly, especially losses to a vented heating pipe
running through the inner chamber.
In most embodiments of the invention, the separator structure includes an
inner wall member defining an outer wall of the inner chamber and an inner wall of
the intermediate chamber and an outer wall member defining an outer wall of the
intermediate chamber and an inner wall of the outer chamber. The peripheral wall of
the tank and the inner and outer wall members of the separator structure are circular
cylindrical and concentric with the axis. The inlet conduit, most preferably, leads into
the outer chamber proximate the bottom wall of the tank. As mentioned above, the
benefits of the invention are especially significant when the heating means includes a
fossil fuel burner and a heating pipe passing through the inner chamber of the tank for
conducting combustion gases through the inner chamber.
It is also advantageous, according to the present invention, for the separator
structure to further separate the tank such as to provide a bottom chamber adjacent the
bottom wall and below the intermediate chamber. When included, the bottom
chamber communicates solely with the outer chamber. It serves the dual purposes of
distributing the water peripherally around the lower end of the outer chamber and
providing a layer of relatively cool water for further isolation of the water in the
intermediate chamber.
For a better understanding of the invention, reference may be made to
the following description of an exemplary embodiment, taken in conjunction with the
accompanying drawings.
Description of the Drawings
Fig. 1 is a schematic side cross-sectional view of the embodiment taken along
the center axis and shows the condition of operation at the point when water is first
drawn from the tank after a standby period; and
Fig. 2 is a schematic side cross-sectional view of the embodiment that is the
same as Fig. 1 but shows the condition of operation at the point when the heat is about
to turn off after having restored the tank to full heat demand capacity.
Description of the Embodiment
The embodiment includes a tank 10 that is capable of containing water under a
supply pressure substantially above atmospheric pressure and has a top wall lOt, a
bottom wall 10b, and a circular cylindrical peripheral wall lOp. In practice, it is
desirable for the top and bottom walls to be segments of spheres, for greater structural
efficiency. The tank 10 is enclosed within a layer 12 of insulation and an outer casing
14. A burner compartment 16 below the tank contains a fossil fuel burner 18 that
delivers hot gases to a heating pipe 20 that extends vertically through the center of the
tank and leads to a vent pipe (not shown). The heating pipe may include baffles, fins
and other elements (not shown) for enhancing the transfer of heat from the
combustion gases to the heating pipe and from the heating pipe to the water in the
tank.
A separator structure 30 is received in the tank between the heating pipe 20
and the peripheral wall and is configured to separate the tank into an inner chamber 32
surrounding the heating pipe, an outer chamber 34 adjacent the perimeter wall lOp, an
intermediate chamber 36 between the inner and outer chambers, and a top chamber 38
adjacent the top wall lOt and above the intermediate chamber. The chambers are in
communication for flow of water along a supply path - indicated by the arrowed lines
F in Fig. 1 - from the outer chamber 34, through the top chamber 38, through the inner
chamber 32 and into the intermediate chamber 36, and a reverse flow path - arrowed
lines RF in Fig. 2 - opposite to the supply path. The intermediate chamber has an
upper closed portion for trapping a mass of gas above a level of water in the tank.
Structurally in the embodiment, the separator structure 30 includes an inner
circular cylindrical wall member 30i, an outer circular cylindrical wall member 30o,
an upper annular wall member 30u that is joined in gas tight relation to the upper ends
of the inner and outer wall members, and a bottom wall member 30b that is joined in
water tight relation to the heating pipe 20. Inasmuch as the separator structure does
not have to sustain any pressure differential, it may be made of thin sheet metal. The
bottom wall member 30b provides, as described below, an open flow path for
distribution of water entering the tank uniformly to the outer chamber 34 and also provides a layer of water below and separated from the water in the intermediate
chamber 36, which is the main storage region of the tank. The bottom wall member
30b, though preferred, is optional, inasmuch as the water can be distributed
peripherally in other ways. When the bottom wall member is omitted, the outer wall
member 30o rests on the bottom wall 10b of the tank in water-tight relation. It is also
possible for the bottom wall member 30b of the separator structure to have a
dependent flange spaced apart from the heating pipe and resting in water-tight relation on the bottom wall 10b of the tank and thus supporting the separator structure in the
tank. The outer wall member 30o may have several leg portions (not shown)
extending to the bottom of the tank and resting on the bottom wall, but leaving most
of the annular region below the lower edge open for water flow. Similarly, for
structural integrity, the inner wall member 30i may have leg portions resting on the
bottom wall member 30b, but also leaving most of the area below the lower edge open. Instead of having terminal edges forming flow passages, holes can be provided
in the members of the separator structure 30.
Cold water from a supply source is conducted into the tank through a cold
water supply conduit 40, which enters the tank at the bottom of the outer chamber 34.
Hot water is drawn from the tank through a hot water outlet conduit 42, which leads
from within the intermediate chamber 36 through the top wall 10.
When the tank is initially filled upon installation or after service, it is not
completely filled but is filled to so that air is trapped in the top of the intermediate chamber. The volume of the air "bubble" in the top of the intermediate chamber is determined on the basis of the "displacement" of water that occurs when hot water is
drawn from the tank and the water in the tank is thereafter reheated to the demand
heat capacity in the manner described below. Filling of the tank must, therefore, be
carried out with due regard for the temperature of the air trapped in the tank at the time of filling. Suitable means for monitoring the temperature of the trapped gas
bubble and the level of water (indicated as "L" in the drawings) in the intermediate chamber when the tank is filled are required. Inasmuch as an air vent pipe 44 from
the intermediate chamber is needed and provided, the installer may insert a thermometer and a level measuring device into the tank through the vent pipe and,
using a calibration chart for the unit, fill it to the proper level. After filling the tank, a
cap 46 is installed on the vent pipe 44. Fig. 1 shows the condition of the tank when it is on standby. When a faucet is
opened and hot water is drawn from the tank through the outlet conduit, cold water
enters the tank and is distributed reasonably uniformly peripherally to the lower end
of the outer chamber 34 by flowing under the bottom wall member 30b of the
separator structure. The entering cold water flows upwardly through the outer
chamber 34, radially inwardly through the top chamber 38, downwardly through the
inner chamber 32, and through the lower orifice(s) at the bottom of the inner wall
member 30i into the intermediate chamber 36. At a suitable time after cold water
starts to flow into the tank, the burner 18, under the control of a thermostatic control
system of the water heater, is ignited. The combustion gases G flowing up the heating
pipe rapidly and efficiently heat the incoming cold water flowing through the inner
chamber 32. As mentioned above, the large temperature difference between the cold
water flowing downwardly along the heating pipe through the chamber 32 and the combustion gases is conducive to a high rate of heat exchange.
As the entering cold water flows along the surfaces of the upper portion of the
separator structure 30, heat is transferred from the upper part of the separator structure
and from the gas bubble trapped in the top of the intermediate chamber 36. As the gas bubble cools, it decreases in volume, thus raising the level L of the water in the
intermediate chamber. When hot water ceases to be drawn from the tank, the burner
continues to burn to restore the tank to the demand heat capacity. As heating of the
water in the tank continues, the gas bubble is heated and expands in volume, thereby
displacing an equal volume of water from the tank along the reverse flow path RF (Fig. 2) and into the supply conduit 40 and supply line. The water flowing along the
flow path, because it is highly heated from passing through the inner chamber 32 and along the heating pipe 20, gives up some heat to the gas bubble and the water in the
intermediate chamber. The hot outflowing water also gives up heat to the peripheral
wall of the tank. Additional heat is given up from the water displaced from the tank
in the cold water supply piping.
After the burner shuts off, heat exchanges within the tank and from the tank to
the outside through the tank walls - most significantly, from the heating pipe to the
vent - relatively quickly lower the temperature of the gas bubble in the top of the tank.
The cooling of the gas bubble causes it to contract, thereby allowing cold water to
enter from the supply and flow along the supply flow path F. The incoming water
from the supply pushes the hot water along the flow path into the intermediate chamber. The incoming cool water also forms layers around the intermediate
chamber, i.e., in the outer chamber 34, upper chamber 38 and inner chamber 32.
When the water heater is on standby, the layers formed in the inner chamber, top
chamber, and outer chamber isolate the intermediate chamber, which is the main
storage section of the tank, from heat loss to the environment, and especially from the
heating pipe to the vent.
It is apparent from the foregoing description that the tank should be designed
so that the volume of water displaced from the tank by the air bubble between the stable condition of Fig. 1 and the end of a heating cycle (Fig. 2.) should exceed the
total of the volumes of the outer chamber 34, the top chamber 38 and the inner
chamber 32 so that relatively cool water is drawn from the supply into the inner
chamber, thereby to minimize heat losses to the heating pipe and vent.
Claims
I CLAM: 1. A hot water heater comprising a tank having top and bottom walls and a peripheral wall having an axis, the tank being adapted to contain water at a predetermined pressure above atmospheric pressure, a separator structure
received in the tank between the axis and the peripheral wall and separating
the tank into an inner chamber surrounding the axis, an outer chamber adjacent
the perimeter wall, an intermediate chamber between the inner and outer
chambers, and a top chamber adjacent the top wall and above the intermediate chamber, the chambers being in communication for flow of water along a
supply path from the outer chamber, through the top chamber, through the inner chamber and into the intermediate chamber and the intermediate
chamber having an upper closed portion for trapping a mass of gas above a
level of water in the tank, means for heating the water in the inner chamber, an
inlet conduit leading from outside the tank into the outer chamber, and an outlet conduit leading from the intermediate chamber to outside the tank.
2. A hot water heater according to claim 1 wherein the separator structure
includes an inner wall member defining an outer wall of the inner chamber and
an inner wall of the intermediate chamber and an outer wall member defining an outer wall of the intermediate chamber and an inner wall of the outer
chamber, and wherein the peripheral wall of the tank and the inner and outer
wall members of the separator structure are circular cylindrical and concentric
with the axis.
3. A hot water heater according to claim 1 wherein the inlet conduit leads into
the outer chamber proximate the bottom wall of the tank.
4. A hot water heater according to claim 1 wherein the heating means includes a
fossil fuel burner and a heating pipe passing through the inner chamber of the
tank for conducting combustion gases through the inner chamber.
5. A hot water heater according to claim 1 wherein the separator structure further
separates the tank into a bottom chamber adjacent the bottom wall and below the intermediate chamber and wherein the bottom chamber communicates
solely with the outer chamber.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/US1997/013708 WO1999006776A1 (en) | 1997-08-04 | 1997-08-04 | Hot water heater with separator structure |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP1017957A1 true EP1017957A1 (en) | 2000-07-12 |
| EP1017957A4 EP1017957A4 (en) | 2002-10-02 |
Family
ID=22261393
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP97935296A Withdrawn EP1017957A4 (en) | 1997-08-04 | 1997-08-04 | Hot water heater with separator structure |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP1017957A4 (en) |
| AU (1) | AU3826797A (en) |
| WO (1) | WO1999006776A1 (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB519017A (en) * | 1938-08-10 | 1940-03-14 | Frederick George Taylor | Improvements in or relating to electric water heaters |
| GB731769A (en) * | 1953-06-23 | 1955-06-15 | Louis Paul Haussauer | Improvements in electric water-heaters |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1082168A (en) * | 1913-12-23 | Frank Philp | Electric heater. | |
| US1557682A (en) * | 1925-04-10 | 1925-10-20 | Michelle S Gazelle | Electric heater |
| US1885040A (en) * | 1931-06-23 | 1932-10-25 | Arnold Lem | Water heater |
| US2814278A (en) * | 1953-06-02 | 1957-11-26 | Donald L Cameron | Combined water heater and storage tank |
| US4521674A (en) * | 1982-01-18 | 1985-06-04 | Scanlan Harry J | Electric fluid heater employing pressurized helium as a heat transfer medium |
-
1997
- 1997-08-04 AU AU38267/97A patent/AU3826797A/en not_active Abandoned
- 1997-08-04 WO PCT/US1997/013708 patent/WO1999006776A1/en not_active Application Discontinuation
- 1997-08-04 EP EP97935296A patent/EP1017957A4/en not_active Withdrawn
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB519017A (en) * | 1938-08-10 | 1940-03-14 | Frederick George Taylor | Improvements in or relating to electric water heaters |
| GB731769A (en) * | 1953-06-23 | 1955-06-15 | Louis Paul Haussauer | Improvements in electric water-heaters |
Non-Patent Citations (1)
| Title |
|---|
| See also references of WO9906776A1 * |
Also Published As
| Publication number | Publication date |
|---|---|
| AU3826797A (en) | 1999-02-22 |
| WO1999006776A1 (en) | 1999-02-11 |
| EP1017957A4 (en) | 2002-10-02 |
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