Abstract: A thermal transfer device comprising a thermal transfer surface and a passageway for conducting a thermal transfer fluid from an inlet to an outlet while passing in thermal contact with the thermal transfer surface. The passageway has at least two spiral passages and a connection channel connecting the at least two spiral passages to permit flow of the heat transfer fluid from a first spiral passage to a second spiral passage; thereby forming a path for the flow of the thermal fluid from the inlet, through the passageway, along the first spiral passage to the connection channel, then along the connection channel to the second spiral passage, and then to the outlet.

Abstract: A pulsed combustion high capacity boiler has air inlet flapper valves at an inlet air decoupler toward a combustion chamber, with a fuel supply and an ignitor upstream of the combustion chamber along a flow path. The combustion chamber is immersed in a water jacket, and downstream of the combustion chamber a plurality of exhaust pipes are immersed in the water jacket and lead to an exhaust decoupler. The exhaust decoupler is disposed outside of the water at the periphery of the unit. An orifice assembly along the flow path defines a flow restriction producing turbulence and preferably serially combines a reduction in cross sectional area followed by a diverter having vanes to induce further turbulence. The ignitor and fuel supply are enabled by a controller that senses spark and combustion flame, and also enables a blower at least during a startup interval. The air inlet flapper admits air, opening and closing at a resonant frequency during combustion.

Abstract: A compact gas fired water heater is provided for recreational vehicles or the like, with higher recoveries and greater efficiencies resulting from increased heating surface and smoother flow of gases in the combustion chamber. The combustion chamber is comprised of two straight horizontal lengths of tube joined in the rear by a specially formed coupler with an additional plate between the tubes to close the front of the coupler.

Abstract: This disclosure relates to a heat exchanger including a plurality of cylindrical walls that are joined together to form at least one annular chamber. A plurality of tubes spiral through the chamber, each of the tubes forming a coil and the coils being axially separated. A fluid is moved in one direction through the coiled tubes, and simultaneously another fluid is moved through the chamber, thereby producing a transfer of heat between the two fluids. In the instance where the heat exchanger is used as a boiler or steam generator, the fluid in the tubes is water or water vapor, and the fluid in the chamber is hot exhaust gases from a burner mounted at the center of the exchanger.

Abstract: A heater for air and liquid utilizing a combustible fuel which includes a first vertical stack including a combustion tube or heat stack with a bottom burner. The heat stack is surrounded by a heat transfer unit with alternate down passages and up passages. The down passages carry the heated exhaust gas. The up passages carry the fluid to be heated. A second vertical stack carries outgoing combustion gases, incoming secondary air supply for combustion, and incoming air to be heated or fluid to be heated. A heat transfer arrangement in the second stack transfers heat from outgoing combustion gases to incoming space air and combustion support air when the unit is used as a space heater.

Abstract: A heat exchanger is formed of a pair of concentrically arranged open-ended cylindrical shells, defining a chamber therebetween, in through which water can pass. Each end of the pair of shells is closed by a removable cap. A combustion element extends into the inner shell from one end along the axis thereof and is connected to a source of heat such as a gas/air mixture which ignites in the combustion element causing the radiation of heat outwardly from the combustion element. A continuous helical wire is located in the chamber, between the inlet and the outlet and in contact with the opposing walls of the chamber to convert the chamber into an elongated helical passage.

Abstract: Apparatus for delivering hot water includes a vessel for releasably containing water and a heat generator compartment in heat transfer relation to the vessel. A conduit in the vessel circumscribes the exhaust funnel of the heat generator and has an inlet port in fluid communication with the vessel and an outlet port in fluid communication with the exterior of the vessel. An after-burner may be situated in the exhaust funnel in registry with the conduit and the conduit can be a coil arranged in spiral configuration.

Abstract: A fluid heater embodies an upright shell with discs vertically arrayed in the shell interior. The discs are angled and configured induce spiral upward flow of hot gases, in external contact with the discs which themselves contain or pass fluid to be heated.

Abstract: A hot water boiler, particularly for central heating systems, has a double-walled structure containing water passages and bounding a combustion chamber, and a multi-walled structure outside the double-walled structure providing passages for the combustion gases and the incoming air for combustion. In order to increase thermal efficiency, while providing an economic and simple design, the double-wall structure is a pair of opposed hollow metal castings which bound not only the combustion chamber but also a combustion gas passage leading upwardly from that chamber and having in it projections integrally formed on the castings. Outside the castings are walls providing, in sequence, downward and upward passages for combustion gas and a downward passage for combustion air.

Abstract: Steam is generated by moving liquid into contact with a (pre-heated) heat retaining substance, typically metal. The heat retaining subtance is maintained at essentially a predetermined temperature by a heat responsive switch that electrically commences and terminates the combustion of fuel for heating the heat retaining substance. Fluid is moved into contact with the heat retaining substance in response to pressure changes in the apparatus so that the pressure within the apparatus is maintained at essentially a predetermined pressure. Superheated gas (steam) may or may not be formed in the process. An expanded surface area for heating the heat retaining substance is provided; an expanded surface area for heating fluid by the heat retaining substance is provided; and an expanded surface area for heating liquid by superheated gas, if present, is provided for generation of steam.