Downfired high efficiency gas-fired water heater

Patent metadata

Field	Value
Publication number	US-9714774-B2
Application number	US-201313942343-A
Country	US
Kind code	B2
Filing date	Jul 15, 2013
Priority date	Aug 22, 2012
Publication date	Jul 25, 2017
Grant date	Jul 25, 2017

Abstract

A high efficiency downfired gas water heater is provided which has a tank for storing water to be heated, a combustion chamber extending downwardly through a top end of the tank, and a gas burner operative to create hot combustion products within the combustion chamber. At the bottom end of the tank is a transfer chamber coupled to an external discharge conduit and to a single pass heat exchanger, in the form of multiple flue tubes. extending vertically through the tank and connected to the combustion chamber. In one embodiment of the water heater the burner is a power burner which forces the combustion products sequentially through the combustion chamber, heat exchanger, transfer chamber and discharge conduit. In another embodiment of the water heater a draft inducer fan is used to draw the combustion products through this path from the combustion chamber.

First claim

What is claimed is:

1. A fuel-fired liquid heating apparatus comprising:
a tank adapted to hold a quantity of liquid to be heated, said tank having upper and lower ends;
a combustion products transfer chamber structure underlying said lower end of said tank, said combustion products transfer chamber structure being a single chamber having a top wall defined by and sized to match said lower end of said tank, said top wall being convexly shaped to be higher in a central region of said tank than at sides of said tank, said combustion products transfer chamber structure having a first sidewall;
a combustion product discharge conduit disposed externally of said tank and having an inlet end communicating directly with an interior of said combustion products transfer chamber structure through an opening in said first sidewall of said combustion products transfer chamber structure, said combustion product discharge conduit having a vertically extending portion adjacent said tank;
a partially submerged combustion chamber extending downwardly into an interior of said tank through said upper end thereof, said partially submerged combustion chamber being spaced upwardly apart from said lower end of said tank, said partially submerged combustion chamber comprising at least one second sidewall and a bottom wall that define an interior space of said partially submerged combustion chamber, and said partially submerged combustion chamber disposed in said interior of said tank such that an exterior surface of said bottom wall and at least a portion of said at least one second sidewall of said partially submerged combustion chamber are in direct contact with said quantity of liquid to be heated;
a single pass heat exchanger structure disposed in said interior of said tank and being defined by a plurality of flue pipes intercommunicating said partially submerged combustion chamber and said combustion products transfer chamber structure, said plurality of flue pipes having inlets and outlets respectively connected directly to said partially submerged combustion chamber and said combustion products transfer chamber structure, respectively, wherein said single pass heat exchanger is a condensing heat exchanger structure;
a condensate drain fitting disposed on said combustion products discharge conduit at a location adjacent a bottom of said vertically extending portion of said combustion product discharge conduit at a location laterally displaced from said tank; and
a fuel burner operative to create hot combustion products within said interior space of said partially submerged combustion chamber for transfer therefrom sequentially through said plurality of flue pipes, into said combustion products transfer chamber structure, and then outwardly from said combustion products chamber structure into said combustion products discharge conduit.

2. The fuel-fired liquid heating apparatus of claim 1 wherein:
said apparatus is a fuel-fired water heater.

3. The fuel-fired liquid heating apparatus of claim 2 wherein:
said water heater is a gas-fired water heater.

4. The fuel-fired liquid heating apparatus of claim 1 wherein:
said plurality of flue pipes have straight configurations and longitudinally extend parallel to a vertical axis extending through said tank.

5. The fuel-fired liquid heating apparatus of claim 1 wherein:
said plurality of flue pipes spiral around a vertical axis extending through said tank.

6. The fuel-fired liquid heating apparatus of claim 1 :
wherein said bottom wall of said partially submerged combustion chamber has a plurality of through apertures disposed within a perimeter of said bottom wall,
wherein said plurality of through apertures disposed in said bottom wall of the said partially submerged combustion chamber are configured to receive inlets of said plurality of flue pipes therethrough,
wherein each through aperture of said plurality of through apertures has a diameter that is smaller than a diameter of said bottom wall of said partially submerged combustion chamber, and
wherein a diameter of each flue pipe of said plurality of flue pipes is smaller than said diameter of said bottom wall of said partially submerged combustion chamber.

7. The fuel-fired liquid heating apparatus of claim 1 wherein:
said fuel burner extends downwardly into said interior space of said partially submerged combustion chamber.

8. The fuel-fired liquid heating apparatus of claim 1 wherein:
said fuel burner is a powered fuel burner operative to sequentially force said hot combustion products downwardly through said partially submerged combustion chamber, downwardly through said flue pipes into said combustion products transfer chamber structure, and then outwardly from said combustion products chamber structure into said combustion products discharge conduit.

9. The fuel-fired liquid heating apparatus of claim 1 further comprising:
an induced draft blower connected to said combustion product discharge conduit and operative to sequentially draw said hot combustion products downwardly through said partially submerged combustion chamber, downwardly through said flue pipes into said combustion products transfer chamber structure, and then outwardly from said combustion products transfer chamber structure into and through said combustion products discharge conduit.

10. The fuel-fired liquid heating apparatus of claim 9 wherein:
said induced draft blower, during operation thereof, maintains a negative pressure in said partially submerged combustion chamber and said combustion products transfer chamber structure.

11. A fuel-fired liquid heating apparatus comprising:
a tank adapted to hold a quantity of liquid to be heated, said tank having upper and lower ends;
a combustion products transfer chamber structure underlying said lower end of said tank, said combustion products transfer chamber structure being a single chamber having a top wall defined by and sized to match said lower end of said tank, said top wall being convexly shaped to be higher in a central region of said tank than at sides of said tank, said combustion products transfer chamber structure having a first sidewall;
a combustion product discharge conduit disposed externally of said tank and having an inlet end communicating directly with an interior of said combustion products transfer chamber structure through an opening in said first sidewall, said combustion product discharge conduit having a vertically extending portion adjacent said tank;
a combustion chamber extending downwardly into an interior of said tank through said upper end thereof, said combustion chamber being spaced upwardly apart from said lower end of said tank, said combustion chamber having a bottom end wall, at least one second sidewall, and a top end that define an interior space of said combustion chamber, said top end being disposed at substantially the same elevation as said upper end of the tank, and said combustion chamber disposed in said interior of said tank such that an exterior surface of said bottom end wall and at least a portion of said at least one second sidewall of said combustion chamber are in direct contact with said quantity of liquid to be heated;
a single pass heat exchanger structure disposed in said interior of said tank and being defined by a plurality of flue pipes intercommunicating said combustion chamber and said combustion products transfer chamber structure, said flue pipes having inlets and outlets respectively connected directly to said bottom end wall of said combustion chamber and said combustion products transfer chamber structure, respectively, wherein said single pass heat exchanger is a condensing heat exchanger structure;

Assignees

• Rheem Mfg Co

Inventors

• Boros Jozef
• Zhang Qian
• Semba Yoshiki
• Thenappan Subbramanian

Classifications

• F22B21/348

  Radiation boilers with a burner at the top · CPC title

• F24H1/206 Primary

  with submerged combustion chamber · CPC title

• F24H1/287

  with the fire tubes arranged in line with the combustion chamber · CPC title

• F24H8/006

  Means for removing condensate from the heater · CPC title

• Y02B30/106

  Cross-Sectional Technologies · mapped topic