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Publication numberUS3707142 A
Publication typeGrant
Publication dateDec 26, 1972
Filing dateSep 24, 1971
Priority dateJan 26, 1971
Also published asDE2201317A1, DE2201317B2, DE2201317C3
Publication numberUS 3707142 A, US 3707142A, US-A-3707142, US3707142 A, US3707142A
InventorsShiro Kobayashi
Original AssigneePaloma Kogyo Kk
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Heat-preserving boiler
US 3707142 A
Abstract
The invention adds to a heat preserving boiler of the type including a water tank, a flue pipe extending vertically therethrough, and a combustion chamber disposed under the water tank, apparatus for improving the efficiency including a drum spaced from and surrounding the water tank to form an annular downward outlet air passage between the outer surface of the water tank and the inner surface of the drum, a cover spaced about the drum to form an annular upward outlet air passage between the outer surface of the drum and the inner surface of the cover, a housing spaced about the cover to form an annular inlet air passage, and an outlet duct connected with the upward outlet air passage to lead exhaust gases to the atmosphere, the outlet duct being disposed within the inlet duct to form an extended inlet air passage.
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United States Patent Kobayashi Dec. 26, 1972 HEAT-PRESERVING BOILER Inventor: Shiro Kobayashi, Nagoya, Japan Assignee:

Nagoya-shi, Japan Filed: Sept. 24, 1971 Appl. No.: 183,521

Foreign Application Priority Data I Jan. 26, 1971 Japan ..46l294l US. Cl. "122/17, 126/85 B m. 01 ..F22b 9/02 Field of Search ..l22/17; 126/85 B, 350

References Cited UNITED STATES PATENTS 5/l963 Vitale ..122/l7 Paloma Kogyo Kabushiki Kaisha, 57

1/1970 Kramer .Q ..l22/l7 Primary Examiner-Kenneth W. Sprague Attorney-Barman, Davidson and Berrnan ABSTRACT The invention adds to a heat preserving boiler of the type including a water tank, a flue pipe extending vertically therethrough, and a combustion chamber disposed under the water tank, apparatus for improving the efficiency including a drum spaced from and surrounding the water tank to form an annular downward outlet air passage between the outer surface of the water tank and the inner surface of the drum, a cover spaced about the drum to form an annular upward outlet air passage between the outer surface of the drum and the inner surface of the cover, a housing spaced about the cover to form an annular inlet air passage, and an outlet duct connected with 7 Claims, 5 Drawing Figures PATENTED nan 2 6 m2 R O T N E V m SH/ R0 KOBA YA 671/,

BY 1% 5 I mm f ATTORNEYS HEAT-PRESERVING BOILER BACKGROUND OF THE INVENTION The present invention relates to a heat-preserving boiler, and more particularly to an improved apparatus providing better combustion, heating and heat-preserving effects for the heat-preserving boiler.

In conventional types of heat-preserving boilers, a common outlet air passage is usually provided which simply extends vertically upward from a combustion chamber through the central portion of a water tank and is connected to a vertical chimney or the like. Counter-blow check means is disposed between the passage and the chimney. Thus, a strong wind pressure blowing into the chimney closes the check means and causes the exhaust gases to remain stagnantly at the level of the counter-blow check means rather than move from the combustion chamber into the atmosphere through the chimney. This causes incomplete combustion within the combustion chamber which is dangerous and uneconomic.

To eliminate the above disadvantage, a large diameter, long and vertical chimney has been applied and affixed onto the outlet air passage, but this has served only to limit the placement of the boiler, no improvement being obtained from the new appended chimney.

SUMMARY OF THE INVENTION An object of the present invention is, therefore, to provide a heat preserving boiler incorporating novel outlet and inlet air passages which overcome the above-explained disadvantages of conventional boilers and prevent dangerous, uneconomic and incomplete combustion caused by inefficient air exhaustion which is attributed particularly to the counter-blow in the chimney.

Another object of the present invention is to provide a heat-preserving boiler, having the above-mentioned characteristics, wherein the exhaust air is utilized to increase efficiency by preserving the heat in,as well as increasing the heat applied to the boiler content.

Yet another object of the present invention is to provide a heat-preserving boiler, having the above-mentioned characteristics, wherein the chimney can be made very compact, thus reducing the production cost.

A further object of the present invention is to provide a heat-preserving boiler, having the above-mentioned characteristics, and wherein the construction is such as not to limit placement of the boiler, so that the boiler may be installed in places where vertical chimneys cannot be used.

According to the present invention briefly summarized, there is provided, in a heat-preserving boiler having a water tank therein, a flue pipe extending vertically within the water tank, a combustion chamber disposed under the water tank, and a water admission arrangement and a water delivery system connected with the water tank, an apparatus which comprises, in combination, a drum disposed over the water tank and forming an annular downward outlet air passage between the outside wall of the water tank and the in-- side wall of the drum, the upper end plate of the drum making a ceiling slightly above the flue pipe, a-partition cover positioned over the drum and forming an annular upward outlet air passage between the outside of the drum and the inside of the cover, the cover including a concentrical opening in the upper plate thereof, a housing disposed over the cover and forming an annular inlet air passage between the inside of the housing and the outside of the cover, the housing including a concentrical opening in the top plate thereof, and the inlet air passage being connected with the combustion chamber through the lower end portion of the cover, an inlet duct connected with the opening of the housing, and an outlet duct connected with the opening of the cover to lead exhaust gases to atmosphere through the outlet air passages, the outlet duct being disposed within the inlet duct to form an extended inlet air passage between the outer surface of the outlet duct and the inner surface of the inlet duct.

BRIEF DESCRIPTION OF THE DRAWING The above-described and other objects and features of the present invention will become more apparent from the following specification, especially when read in conjunction with the accompanying drawing, in which:

FIG. 1 shows an elevational section of a preferred embodiment of the present invention;

FIG. 2 is a partial rear side view of the apparatus shown in FIG. 1;

FIG. 3 is a cross-sectional view taken from line III III of FIG. 1 looking in the direction of the arrows;

FIG. 4 is a cross-sectional view taken along line IV- IV of FIG. 1 and looking in the direction of the arrows, and

FIG. 5 is a cross-sectional view taken on line VV of FIG. 1 looking in the direction of the arrows.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, and more particularly to FIG. 1 thereof, a preferred embodiment of the present invention comprises in its innermost part a cylindrical water tank 1 with a flue pipe 10 provided coaxially in the central portion of the water tank 1. The outer circumference of the water tank 1 is covered with a hollow cylindrical drum 4 having an inverted U-shape in cross-section. Between the water tank 1 and the drum 4 is an appropriate annular space forming an annular downward outlet air passage 2. The upper end circular plate of the drum 4 makes a ceiling 3 just above the flue pipe 10 of the water tank 1. A hollow cylindrical partition cover 6 is lined with suitable heatproof and heat-preserving material such as glass wool, asbestos, or the like. The partition cover 6 is so positioned as to cover the internal drum 4 and to provide an appropriate annular space between the lined inner circumferential surface thereof and the outer circumferential surface of the drum 4. The annular space forms an upward outlet air passage 5 which is in open communication with the downward outlet air passage 2 at the lower end portion of the drum 4.

Thus, vertically and coaxially through the water tank 1 at the center thereof, the flue pipe 10 extends from the upper end portion of a combustion chamber 9 to the upper end portion of the water tank 1 to communicate with the outlet air passages 2 and 5.

The partition cover 6 is covered over the outer circumference thereof with a hollow cylindrical housing 8. An annular space constituting an inlet air passage 7 is formed between the inner circumferential surface of the housing 8 and the outer circumferential surface of the partition cover 6. The inlet air passage 7 is in open communication with the combustion chamber 9 through a plurality of vent holes 1 l drilled through the lower end portion of the partition cover 6.

An outlet duct 12 communicates with a concentrical circular opening cut in the ceiling of the partition cover 6 an, thus, opens to the upward outlet air passage 5. An inlet duct 13 communicates with a concentrical opening in the ceiling of the housing 8 and, thus, opens to the inlet air passage 7. The outlet duct 12 may be disposed coaxially or eccentrically within the inlet duct 13.

in this preferred embodiment as shown in FIG. 1, the outlet duct 12 and the inlet duct 13 turn at a right angle at a point slightly above the ceiling of the housing 8, so

that the two ducts extend rearwardly. The horizontally extended portion of the outlet duct 12 is positioned eocentrically upward within the inlet duct 13. The open end 14 of the outlet duct 12 protrudes slightly beyond the open end 15 of the inlet duct 13.

The heat-preserving boiler in this embodiment is further provided with a water supply pipe 16 connected to the lower portion of the water tank 1 and a hot-water outlet pipe 17 extending to the outside of the boiler from the upper portion of the water tank 1. A gas burner 18 is also provided and a gas supply pipe therefor is connected to an automatic gas flow control apparatus 19 that controls the flow of gas by detecting precisely the temperature of water inside the water tank 1. As illustrated in FIG. 1, the heat-preserving boiler of this embodiment is properly installed to a wall D through a fixing hole 20 providedtherein for the inlet and outlet ducts 13 and 12 which are more firmly held by the fixing metal parts 21.

The novel operation of the apparatus in accordance with the present invention is described in detail hereinafter. After filling the water tank 1 with fresh water through the water supply pipe 16, the gas burner 18 is tired. This heats up the combustion chamber 9, and heated air and exhaust gases pass upwardly through the vertical flue pipe 10. Thus, water in the water tank 1 is heated at the bottom of the water tank 1 as well as centrally through the wall of the flue pipe.

The heated air and gases ascending through the flue pipe are turned from their upward movement by the ceiling 3 of the internal drum 4, and then descend through the outlet air passage 2, heating the outer circumferential wall of the water tank 1 with their remaining heat. This increases the heating effect on the water inside the water tank 1.

When the heated air and gases reach the lower end of the outlet air passage 2, they turn upward, entering the outlet air passage 5. At the end of their upward movement in passage 5, the heated air and exhaust gases enter the outlet duct 12 to be completely discharged.

Supply of fresh air to the combustion chamber 9 is properly carried out by inflow of air from the opening of the inlet duct 13. The inflow of air passes through the inlet duct 13 into the inlet air passage 7. The air is further lead into the combustion chamber 9 through the plural vent holes 1 1.

As has been explained, the outlet duct 12 extends coaxially or eccentrically within the inlet duct 13, and

the opening 14 of the outlet duct 12 protrudes slightly beyond the opening 15 of the inlet duct 13. Consequently, the openings 14 and 15 of the outlet and inlet ducts 12 and 13 respectively, being offset on different planes, the inflow of the fresh air and outflow of the heated air do not affect each other and eliminate undesired effects of the wind pressure against the two openings 14 and 15. Furthermore, the described construction is such that unnecessary and harmful outside air is not allowed to enter the outlet duct 12. Thus, any possibility of counter-blow of exhaust air into the combustion chamber 9 caused by counter-blow of fresh air into the outlet duct 12 is prevented. On the other hand, a constant supply of fresh air into the combustion chamber 9 is obtained by the inflow of air through the inlet duct 13 and the inlet air passage 7 which is completely separated from the outlet air passage 5 by the partition cover 6. This provides stable and effective combustion in the combustion chamber 9. Furthermore, the remaining heat of the heated air is effectively utilized to heat the circumferential wall of the water tank 1 as it is being exhausted through the outlet air passage 2.

When the water inside the water tank 1 reaches a predetermined temperature, the gas burner 18 is shut off. At .this moment, the temperature inside the flue pipe 10 is almost equal to that in the outlet air passages 2 and 5. Thus, natural air convection ceases so that, consequently, the heated air is effectively utilized to preserve the temperature of the hot water inside the water tank 1.

The heat-preserving boiler as described does not require any special chimney or the like for the outflow of the exhaust air. It can be simply and easily set up in a desired and appropriate location with the duct ends 14 and 15 projecting slightly beyond the wall of the location and through an opening provided in such wall. This eliminates to a great extent restrictions as to placement and installation of conventional boilers.

Although a certain specific embodiment of the invention has been shown and described, it is obvious that many modifications thereof are possible. The invention, therefore, is not intended to be restricted to the exact showing of the drawing and description thereof, but is considered to include reasonable and obvious equivalents.

We claim:

1. The combination with a heat-preserving boiler, including a water tank therein, a flue pipe extending vertically through said water tank, a combustion chamber disposed under said water tank, water admission means, and water delivery means connected with said water tank, of a tubular drum having a wall at its upper end spaced from and surrounding said water tank to form an annular downward outlet air passage between the outer surface of said water tank and the inner surface of said drum, the upper end wall of said drum defining a ceiling above said-flue pipe, a tubular cover having a wall at its upper end with an opening therein and positioned over said drum to form an annular upward outlet air passage between the outer surface of said drum and the inner surface of said cover, a tubular housing having a wall at its upper end with an opening therein and disposed over said cover to form an annular inlet air passage between the inner surface of the hous- IO60l2 0156 ing and the outer surface of said cover, said inlet air passage being connected with said combustion chamber through openings at the lower end portion of said cover, an inlet duct communicating with said inlet air passage and connected to said opening in the upper wall of said housing, and an outlet duct connected with said opening in the upper wall of said cover and communicating with said outlet air passages to lead exhaust air to atmosphere, said outlet duct being disposed within said inlet duct to form an extended inlet air passage between the outer surface of said outlet duct and the inner surface of said inlet duct.

2. The combination as set forth in claim 1, in which said outlet duct is disposed coaxially within said inlet duct.

3. The combination as set forth in claim 1, in which said outlet duct is disposed eccentrically within said inlet duct.

4. The combination as set forth in claim 1, in which said outlet duct projects out from the open end portion of said inlet duct.

5. The combination as set forth in claim 1, in which said inlet and outlet ducts turn substantially at a right angle above said housing, said inlet and outlet ducts maintaining their parallel relationship to each other throughout their lengths.

6. The combination as set forth in claim 1, in which said cover is lined with glass wool material.

7. The combination as set forth in claim 1, in which said cover is lined with asbestos material.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
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US3490420 *Dec 13, 1967Jan 20, 1970Gulf Research Development CoInduced draft oil-fired water heater
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3921592 *Dec 12, 1974Nov 25, 1975Saunier DuvalArrangement and mounting of the enclosure and combustion chamber of a forced-draft boiler
US4253426 *Oct 20, 1978Mar 3, 1981Mitsubishi Denki Kabushiki KaishaReservoir type water heating device
US4295447 *Sep 5, 1979Oct 20, 1981Interliz AnstaltHeating boiler and temperature control therefor
US4338888 *May 14, 1980Jul 13, 1982Advanced Mechanical Technology, Inc.High efficiency water heating system
US4366778 *Mar 26, 1981Jan 4, 1983Paquet Thermique, S.A.Gas boiler able to operate in a sealed combustion circuit
US4387669 *Mar 29, 1982Jun 14, 1983Murrell's Welding Works, Inc.Heater
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US4445464 *Jul 12, 1982May 1, 1984Advanced Mechanical Technology, Inc.High efficiency water heating system
US4448136 *Jul 6, 1982May 15, 1984British Gas CorporationBoiler with waste heat recovery
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US5020512 *Jun 24, 1987Jun 4, 1991State Industries, Inc.Water heater construction and method of heating water
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US5924390 *Feb 28, 1997Jul 20, 1999Bock; John C.Water heater with co-located flue inlet and outlet
US7013841Feb 1, 2005Mar 21, 2006Rheem Manufacturing CompanyDifferently configured fuel-fired water heaters constructed from identical production platforms
US7159540Oct 20, 2004Jan 9, 2007American Water Heater CompanyWater heater with air intake and exhaust system
US8113154Oct 24, 2008Feb 14, 2012Aos Holding CompanyTransition element for a passage in a water heater
Classifications
U.S. Classification122/19.2, 122/18.31, 122/18.2, 126/85.00B
International ClassificationF22B9/04, F24H1/20, F23L17/00, F23L1/00
Cooperative ClassificationF22B9/04, F24H1/205
European ClassificationF22B9/04, F24H1/20C