MXPA06010145A

MXPA06010145A - Looped system fuel-fired fluid heating/storage device.

Info

Publication number: MXPA06010145A
Application number: MXPA06010145A
Authority: MX
Inventors: Ozzie Missoum; Gregory M Welk; Phillip W Stephens; Qian Zhang; Jeffrey M Haney
Original assignee: Rheem Mfg Co
Priority date: 2005-09-08
Filing date: 2006-09-06
Publication date: 2007-03-07
Also published as: AU2006203707B2; CA2556012A1; AU2006203707A1; AU2006203707C1; US20070051359A1; NZ551184A; NZ549446A

Abstract

A fuel-fired commercial water heater has a three-pass condensing type heat exchanger disposed within its tank and having a vertical flue connected at its lower end to a central collector plenum horizontally circumscribed by an outer plenum to which an exhaust pipe is coupled. A series of vertical tube structures are disposed above and intercommunicate the central and outer collector plenums. The outlet of a fuel burner is coupled to the upper end of the flue and is operative to sequentially flow combustion gases downwardly through the flue into the central collector plenum, upwardly and then downwardly through the tube structures into the outer collector plenum and then outwardly through the exhaust pipe.

Description

HEATING DEVICE / STORAGE OF FLUID HEATED BY FUEL WITH SYSTEM IN LOOP DESCRIPTION OF THE INVENTION The present invention relates generally to fuel-heated fluid heating devices and, in representatively illustrated embodiments thereof, more particularly provides a fuel-heated water heater having a specially designed multistep condensing-type heat exchanger. incorporated in it. Conventional fuel-heated water heaters are typically of a "one-step" non-condensing configuration, implying that the hot combustion gases used to heat the water stored in the tank are only subjected to a single pass through. a heat exchanger structure (normally a vertical duct) inside the tank before discharging the water heater to, for example, an external vent structure, and that the condensation of the flue gas does not occur to any appreciable degree in the structure of the heat exchanger inside the heater tank of water. In this conventional type of fuel-heated water heater, the overall thermal efficiency is typically limited to about 80-85%. Various proposals have been made to provide fuel-heated water heaters with condensation-type single-pass heat exchangers (i.e., in which the combustion gases condense inside the heat exchanger). However, previously proposed one-step condensation type heat exchange structures incorporated in fuel-heated water heaters typically provide water heaters with limited thermal performances in the range of 85-90%. In an attempt to increase its thermal efficiency above 95%, multi-stage condensation heat exchangers of various configurations and types have been proposed for installation within the portions of the tank of water heaters heated by fuel. While such previously proposed multistep condensing type heat exchangers have met this thermal performance goal, several problems, limitations and disadvantages have also been undesirably presented. These include increased complexity of the heat exchanger, higher material and manufacturing costs, condensation handling problems, increased operational noise, and reduced operational life of the heat exchanger. Thus, it may be desirable to provide a fuel heated water heater, or other type of fuel heated fluid heating device, with an improved multipass condensing type heat exchanger. It is mainly to this goal that the present invention is directed. In carrying out the principles of the present invention, in accordance with representative embodiments thereof, a fuel-heated fluid heating apparatus is provided which is representatively a commercially heated water heater for fuel, but 1. Alternatively, it may be another type of fuel-heated water heater or other type of fuel-heated fluid heating apparatus, such as, for example, a boiler. In general, the apparatus comprises a tank for containing a fluid to be heated, and a heat exchanger disposed in the tank and having an internal combustion gas flow path defined by (1) a first passage section having an inlet portion and an outlet portion separated from the inlet portion of the first passage section in a first direction, (2) a central collector impeller coupled to the outlet portion of the first passage section, (3) a second passage section having a portion of inlet coupled to the central manifold impeller and a separate outlet portion of the inlet portion of the second passage section in a second opposite direction of the first direction, (4) a third passage section having an entrance portion coupled to the exit portion of the second passage section and an exit portion separated from the entrance portion of the third passage section in the first direction, ( 5) an outer collector impeller circumscribing the collector impeller and engaging the outlet portion of the third through section, and (6) an exhaust section coupled to the outer collector impeller. Additionally, the apparatus comprises an efficient combustion system for flowing the hot combustion gases towards the inlet portion of the first through section and then through the remainder of the heat exchanger. In a first embodiment thereof, the apparatus is a fuel-heated water heater comprising a tank for containing the water to be heated, and a condensation-type multi-stage heat exchanger disposed within the tank. The heat exchanger includes (1) a vertically extending conduit having an upper inlet end and a lower outlet end, (2) a central manifold impeller coupled to the lower outlet end of the conduit, (3) an outer manifold impeller horizontally circumscribing the central manifold impeller, (4) a plurality of vertically extending inverted U-shaped tubes horizontally spaced around of the conduit, each inverted U-shaped tube has a lower inlet end coupled to the central manifold impeller, and a lower outlet end coupled to the outer manifold impeller, and (5) an exhaust pipe having an inlet portion coupled to the outlet manifold. impeller exterior collector. The water heater also comprises a fuel burner (which can be either a fuel-powered burner or a non-energized burner) having an outlet coupled to the upper inlet end of the duct, the fuel burner is effective to flow the combustion gases through the duct and then through the rest of the condensation type heat exchanger. In a second embodiment thereof, the apparatus is a fuel-heated water heater comprising a tank for containing water to be heated, a transfer impeller disposed externally to the tank at an upper end portion thereof, and a heat exchanger for multipaso of condensation type disposed inside the tank. The heat exchanger includes (1) a vertically extending conduit having an upper inlet end and a lower outlet end, (2) a central collector impeller coupled to the lower outlet end of the conduit, (3) an outer collector impeller horizontally circumscribing the central collector impeller, (4) a first plurality of vertical tubes spaced horizontally around the conduit and having ends of lower inlets coupled to the central manifold impeller, and upper outlet ends coupled to the transfer impeller, (5) a second plurality of vertical tubes arranged horizontally outward from and horizontally spaced around the first plurality of vertical tubes, the second plurality of tubes verticals have upper inlet ends coupled to the transfer impeller, and lower outlet ends coupled to the outer collector impeller, and (6) a scavenge tube having an inlet portion coupled to the outer manifold impeller. The water heater also comprises a fuel burner (which can be either an energized fuel burner or a non-energized fuel burner) having an outlet coupled to the upper inlet end of the conduit, the fuel burner being effective for flow the combustion gases through the conduit and then into the rest of the condensation type heat exchanger. According to other aspects of the invention, a portion of the central collector impeller extends downwardly passing the outer collector impeller, the outer collector impeller has a vertically inclined bottom side having a lower portion to which an inlet portion of the outlet is connected. Exhaust pipe, the inner side of the central manifold impeller has a dome-shaped downward configuration, and a sloping condensate drain line extends into the tank from the inner side of the central manifold impeller to an inlet portion of the exhaust pipe inside the tank. BRIEF DESCRIPTION D? THE DRAWINGS FIGURE 1 is a schematic cross-sectional view through a representative fuel-heated water heater having incorporated therein a specially designed condensing type multi-stage heat exchanger representing the principles of the present invention; and FIGURE 2 is a schematic cross-sectional view through an alternative embodiment of FIGURE 1 of the water heater. In the cross-section schematically illustrated in FIGURE 1 there is a heating / storage device for fuel-heated fluid with loop system representing the principles of the present invention, the device representatively is a commercially heated fuel water heater 10 having a condensation type multi-stage heat exchanger 12 specially designed to be submerged in the stored water 14, pressurized in a portion 16 of the externally insulated tank. As used herein, the term "commercial" water heater means, as is commonly accepted in the water heater industry, a water booster having a heating input rate typically around about 75,000 Btu / Hr. , and a hot water temperature of approximately 82.22 ° C (180 ° F) or more. While the device 10 illustrated is representatively a commercial water heater, it may alternatively be a non-commercial water heater, or another type of heating device for fuel-heated fluid, such as a boiler, without departing from the principles of the present invention. During the heating of the water heater 10, the hot combustion gases 18 of a fuel burner 20 flow over the water heater through the heat exchanger 12 to transfer heat of combustion, with a thermal efficiency of 95% or more, in the water 14 stored. The burner 20 can be either an energized fuel burner or a non-energized fuel burner. When required, pressurized hot water 14 stored in tank 16 can be removed therefrom via an outlet adapter 21 mounted in the tank. Automatically, the extracted water 14 is replaced with pressurized cold water, from a source thereof, through an inlet adapter 23 mounted in the tank. The heat exchanger 12 is of a three-step configuration and includes a vertical conduit portion 22 connected at its upper end to the outlet of the burner 20 and connected at its lower end to a dome-shaped central primary combustion gas impeller 24. inverted circumscribed horizontally by an impeller 26 annular secondary combustion gas manifold having a bottom wall which is vertically inclined in a downward and straight manner as indicated by the arrow 27 inclined in FIGURE 1. A series of tubes 28 in vertically extending inverted U-shape (of which only two are shown in FIGURE 1) are separated around the central conduit 22. Each inverted U-shaped tube 28 has a leg 28a connected and communicated with the central impeller 24 and another leg 28b connected to the annular outer impeller 26 as shown. A flue gas exhaust pipe 30 is connected on the inner side of the annular impeller 26 and has, external to the water heater, a condensate drain adapter 32. A submerged condensate line 34 is interconnected between the inner side of the central impeller 24 and an inlet portion of the exhaust pipe 30 as shown.

During heating of the water heater 10, the combustion gas 18 discharged from the burner 20 sequentially makes a first downward passage through the vertical central duct portion 22, a second passage from the central impeller 24 ascendingly through the legs 28a of the U-shaped tube, and a third downward passage through the legs 28b of the U-shaped tube in the annular outer impeller 26, with the condensation 35 from the combustion gas 18 formed inside the legs 28b of the U-shaped tube as shown. The condensate of the annular impeller 26 flows into the exhaust pipe 30, and any condensate that may be in the central impeller 24 also flows towards the exhaust pipe 30 through the inclined line of condensate. The modified water heater 10a shown in FIGURE 2 is identical to the water heater 10 of FIGURE 1 with the exception that in the modified heat exchanger 12a, the inverted U-shaped tubes 28 (see FIGURE 1) are replaced with straight vertical second pass pipes 36 and tubes 38 of the third straight vertical step. As illustrated in FIGURE 2, the second pass tubes 36 are interconnected between the impeller 24 and a top transfer impeller 40 disposed in the insulation 42 above the upper end 44 of the top of the tank 16, and the tubes 38 of the third step are interconnected between the impellers 26 and 40. During the heating of the water heater 10a, the combustion gases 18 from the burner 20 flow sequentially downwardly through the portion 22 of the vertical central duct towards the central impeller 24 , ascending from the impeller 24 through the vertical tubes 36 towards the upper impeller 40 at the top, and then downwardly from the upper impeller 40 through the vertical tubes 38 towards the inner annular impeller 26 from which discharge through the tube 30 exhaust. The condenser 35 formed in the third passage tubes 38 is discharged from the heat exchanger 12a in a manner similar to that previously described together with the heat exchanger 12 of FIGURE 1. Compared with conventional multistep condensing type heat exchangers used in water heaters heated by fuel, the heat exchangers 12, 12a representatively illustrated and described herein provide a variety of advantages which include, for example, the ability to provide their water heaters associated with thermal performances well in excess of 95%, simplified configuration of the heat exchanger, reduced material and manufacturing costs, quieter operation, increased life of the heat exchanger, and improved condensate handling. As will be readily appreciated by one of skill in this particular art, heat exchangers 12 and 12a representatively illustrated, may have other orientations within their associated water heaters 10 and 10a without departing from the principles of the present invention. For example, the heat exchangers 12 and 12a, with minor modifications thereto, may alternatively and horizontally be oriented within their associated water heaters 10 and 10a. The above detailed description will be clearly understood as being given by way of illustration and example only, the spirit and scope of the present invention are limited only by the appended claims.

Claims

CLAIMS 1. A fuel heated fluid heating apparatus characterized in that it comprises: a tank for containing a fluid to be heated; a heat exchanger disposed in the tank and having an internal combustion gas flow path defined by: a first passage section having an inlet portion and an outlet portion separated from the inlet portion of the first passage section in a first direction, a central manifold impeller coupled to the outlet portion of the first passage section, a second passage section having an inlet portion coupled to the central manifold impeller and an outlet portion separate from the inlet portion of the second passage section in a second opposite direction of the first direction, a third passage section having an entrance portion coupled to the exit portion of the second passage section and an exit portion separated from the entrance portion of the passageway; third section of passage in the first direction, an impellent outer collector that circumscribes the impeller collector and is coupled to the portion n output from the third passage section and an exhaust section coupled to the outer manifold plenum; and an efficient combustion system for flowing the hot combustion gases towards the inlet portion of the first through section and then through the remainder of the flow path.
2. The fuel-heated fluid heating apparatus according to claim 1, characterized in that: the fuel-heated fluid heating apparatus is a water heater heated by fuel.
3. The fuel-heated fluid heating apparatus according to claim 1, characterized in that: the heat exchanger is a condensation-type heat exchanger.
The fuel-heated fluid heating apparatus according to claim 1, characterized in that: the combustion system includes a fuel burner having an outlet coupled to the inlet portion of the first passage section.
The fuel-heated fluid heating apparatus according to claim 1, characterized in that: the first direction generally extends in a downward direction, and the second direction generally extends in an ascending manner.
The fuel-heated fluid heating apparatus according to claim 5, characterized in that: the outer manifold impeller has a lower side vertically inclined with a lower portion, and the exhaust section has an inlet portion coupled to the lower portion.
The fuel-heated fluid heating apparatus according to claim 6, further characterized in that it comprises: a condensate drain line interconnected between a lower side portion of the central header impeller and the exhaust section.
8. The fuel-heated fluid heating apparatus according to claim 5, characterized in that: the central collector impeller extends downwardly beyond the outer collector impeller.
The fuel-heated fluid heating apparatus according to claim 8, characterized in that: the central collecting impeller has a dome-shaped lower side.
The fuel-heated fluid heating apparatus according to claim 1, characterized in that: the central collecting impeller extends by passing the outer collector impeller in the first direction.
The fuel-heated fluid heating apparatus according to claim 1, characterized in that: the second and third passage sections are at least partially defined by a U-shaped tube structure extending in parallel to the first step section and has a first open end coupled to the central manifold impeller, and a second open end coupled to the outer collector impeller.
12. The fuel heated fluid heating apparatus according to claim 1, characterized in that: the second and third passage sections are defined by a plurality of U-shaped tube structures circumferentially spaced around and extending in parallel to each other. the first passage section, each of the U-shaped tube structures has a first open end coupled to the central manifold impeller, and a second open end coupled to the outer manifold impeller.
13. The fuel-heated fluid heating apparatus according to claim 1, characterized in that: the heating device of fuel-heated fluid further comprises a transfer impeller disposed externally of the tank, the second passage section is defined by less a second straight passage tube having an inlet end coupled to the central manifold impeller and an outlet end coupled to the transfer impeller, and the third passage section is defined by at least a third passage tube having an end of input coupled to the transfer impeller and an output end coupled to the external collector impeller.
14. The fuel heated fluid heating apparatus according to claim 13, characterized in that: at least one straight pipe of second pass is a plurality of straight second pass pipes circumferentially spaced around the first through section, and less a straight third passage tube is a plurality of straight third pass tubes spaced circumferentially around the plurality of straight second pass tubes.
15. A fuel-heated water heater characterized in that it comprises: a tank for containing water to be heated; a condensation-type heat exchanger disposed within the tank and having: a vertically extending conduit having an upper inlet end and a lower outlet end, a central manifold impeller coupled to the lower outlet end of the conduit, an outer manifold impeller circumscribing horizontally the central manifold impeller, a plurality of inverted vertically extending U-shaped tubes horizontally spaced around the conduit, each of the inverted U-shaped tubes has a lower inlet end coupled to the central manifold impeller, and a lower outlet end coupled to the exterior collector impeller, and an exhaust pipe having an inlet portion coupled to the exterior collector impeller; and a fuel burner having an outlet coupled to the upper inlet end of the duct, the fuel burner is effective to flow the combustion gases through a duct and then the rest of the condensation type heat exchanger.
16. The fuel-heated water heater according to claim 15, characterized in that: the fuel-heated water heater is a commercial water heater.
17. The fuel-heated water heater according to claim 15, characterized in that: the inlet portion of the exhaust pipe is coupled to a lower side of the outer collector impeller, and the fuel-heated water heater further comprises a line of condensate disposed within the tank and interconnected between the inlet portion of the exhaust pipe and a lower-side portion of the central header impeller.
18. The fuel-heated water heater according to claim 15, characterized in that: the outer manifold impeller has a lower side that slopes downward toward the inlet portion of the exhaust pipe, the lower side having a lower portion a which engages the inlet portion of the exhaust pipe.
19. The fuel-heated water heater according to claim 15, characterized in that: a portion of the central collecting impeller extends downwardly beyond the outer collector impeller.
20. The fuel-heated water heater according to claim 19, characterized in that: the portion of the central collector impeller has a dome-shaped configuration descending.
21. A fuel-heated water heater characterized in that it comprises: a tank for containing water to be heated; a transfer impeller disposed externally of the tank in an upper end portion thereof; a condensation-type heat exchanger disposed within the tank and having: a vertically extending conduit having an upper inlet end and a lower outlet end, a central manifold impeller coupled to the lower outlet end of the conduit, an outer manifold impeller horizontally circumscribing the central manifold impeller, a first plurality of vertical tubes horizontally spaced around the conduit and having lower inlet ends coupled to the central manifold impeller, and upper outlet ends coupled to the transfer impeller, a second plurality of vertical pipes arranged horizontally outward from and horizontally spaced around the first plurality of vertical tubes, the second plurality of vertical tubes have upper inlet ends coupled to the transfer impeller, and lower outlet ends coupled to the outer collector impeller, and an exhaust pipe having an inlet portion coupled to the outer collector impeller; and a fuel burner having an outlet coupled to the upper inlet end of the duct, the fuel burner is effective to flow the combustion gases through the duct and then into the rest of the condensation type heat exchanger.
22. The fuel-heated water heater according to claim 21, characterized in that: the fuel-heated water heater is a commercial water heater.
23. The fuel-heated water heater according to claim 21, characterized in that: the inlet portion of the exhaust pipe is coupled to a lower side of the outer collector impeller, and the fuel-heated water heater further comprises a line of condensate disposed within the tank and interconnected between the inlet portion of the exhaust pipe and a lower-side portion of the central header impeller.
24. The fuel-heated water heater according to claim 21, characterized in that: the outer collector impeller has a lower side that slopes downward toward the inlet portion of the exhaust pipe, the lower side having a lower portion at which engages the inlet portion of the exhaust pipe.
25. The fuel-heated water heater according to claim 21, characterized in that: a portion of the central collecting impeller extends downwardly beyond the outer collector impeller.
26. The fuel-heated water heater according to claim 25, characterized in that: the portion of the central collecting impeller has a dome-shaped configuration descending.