Apparatus and method for burning a combustible gas, and a heat exchanger for use in this apparatus

Apparatus for burning a combustible gas comprising;

• a housing having walls defining a liquid chamber capable of holding liquid;
• a combustion chamber member disposed within said liquid chamber and having liquid-impervious walls defining the combustion chamber;
• an exhaust conduit having an inlet connected to said combustion chamber and an outlet through which combustion products can leave said apparatus;
• a gas burner mounted within said combustion chamber, said burner having walls defining an internal chamber and apertures passing through said walls, thereby establishing fluid communication between said internal chamber of said gas burner and said combustion chamber outside said gas burner;
• an impeller for passing a combustible mixture of said combustible gas and an oxygen-containing gas under pressure into said internal chamber of said gas burner,
• said apertures in said gas burner being sized such that combustion of said combustible mixture within said combustible chamber outside said gas burner will not cause ignition of said combustible mixture within said internal chamber of said gas burner,
• a duct having an air inlet and an air outlet;
• means for moving air through said duct from said air inlet to said air outlet;
• a first heat exchanger disposed within said duct for effecting heat exchange between hot water passing through said heat exchanger and air passing through said duct around said heat exchanger, said heat exchanger having a water inlet and a water outlet;
• a water supply conduit having an inlet disposed within said liquid chamber and an outlet connected to said water inlet of said heat exchanger;
• a water return conduit having an inlet connected to said water outlet of said heat exchanger and an outlet disposed within said liquid chamber, said water return conduit having a section mounted in parallel to a section of said exhaust conduit and configured to cause the combustion products passing along said exhaust conduit and the water flowing along said water return conduit to flow counter-current to one another and to cause heat to flow from said combustion products to said water;
• and
• an outer housing surrounds said housing, at least part of said exhaust conduit is disposed between said housing and said outer housing, and part of said liquid return conduit is disposed within said exhaust conduit.

In combination:

• a heating duct, a water tank, a combustion chamber within said tank, and a burner within said chamber;
• means for supplying a mixture of fuel and oxygen under pressure to said burner;
• means for conducting hot water from the tank to a first heat exchanger mounted within said heating duct;
• means for returning water from said first heat exchanger to said tank;
• a second heat exchanger mounted within said tank, said second heat exchanger being in fluid communication with said combustion chamber for receiving combustion products discharged from said chamber;
• an exhaust conduit in fluid communication with the second heat exchanger for discharging combustion products to the atmosphere;
• a cold water inlet conduit to the tank, said water conduit and said exhaust conduit being mounted in parallel and configured to (1) cause the combustion products and water to flow countercurrent to each other and (2) to cause heat to flow from the combustion product to the cold water;
• and
• an outer cylinder encompassing the tank and chamber, an insulating jacket in the space between the tank and the cylinder, the countercurrent flowing conduits being located within said insulating jacket.

Apparatus for burning a combustible gas comprising;

• a housing having walls defining a liquid chamber capable of holding liquid;
• a combustion chamber member disposed within said liquid chamber and having liquid-impervious walls defining the combustion chamber;
• an exhaust conduit having an inlet connected to said combustion chamber and an outlet through which combustion products can leave said apparatus;
• a gas burner mounted within said combustion chamber, said burner having walls defining an internal chamber and apertures passing through said walls, thereby establishing fluid communication between said internal chamber of said gas burner and said combustion chamber outside said gas burner;
• an impeller for passing a combustible mixture of said combustible gas and an oxygen-containing gas under pressure into said internal chamber of said gas burner,
• said apertures in said gas burner being sized such that combustion of said combustible mixture within said combustion chamber outside said gas burner will not cause ignition of said combustible mixture within said internal chamber of said gas burner,
• a duct having an air inlet and an air outlet;
• means for moving air through said duct from said air inlet to said air outlet;
• a first heat exchanger disposed within said duct for effecting heat exchange between hot water passing through said heat exchanger and air passing through said duct around said heat exchanger, said heat exchanger having a water inlet and a water outlet;
• a water supply conduit having an inlet disposed within said liquid chamber and an outlet connected to said water inlet of said heat exchanger;
• a water return conduit having an inlet connected to said water outlet of said heat exchanger and an outlet disposed within said liquid chamber, said water return conduit having a section mounted in parallel to a section of said exhaust conduit and configured to cause the combustion products passing along said exhaust conduit and the water flowing along said water return conduit to flow countercurrent to one another and to cause heat to flow from said combustion products to said water;
• and
• said exhaust conduit comprises (1) a riser section extending upwardly from said combustion chamber, (2) a helical section extending downwardly from the upper end of said riser section, (3) a first section extending downwardly from the lower end of said helical section, (4) a second section extending upwardly from the lower end of said first section, and (5) a drain conduit extending downwardly from adjacent the junction of said first and second sections.