Abstract: A material drying system includes a pulse combustor having a combustion chamber and an elongate tailpipe forming a resonant system with the combustion chamber. The tailpipe has an inlet for material to be dried and an outlet through which the material is discharged in a pulsating gas stream when the combustor is in operation. The tailpipe discharges into a vertical drying duct which leads to a cyclone separator. Part of the exhaust gas leaving the cyclone separator is recycled and used to cool the combustion chamber and tailpipe. Part of the dried material leaving the cyclone separator can be mixed with new incoming wet material to lower the overall moisture content of the material to be dried. The pulse combustor provides a substantial portion of the motive force required to operate the system.

Abstract: A pulse combustion dehydration apparatus includes a pulse combustor designed to operate with a low pressure fuel gas supply and having valve means to stop the supply of gas to the combustion chamber during high pressure portions of the pulse combustion cycle. Gas enters the combustion chamber through a fuel distributor having a series of radial gas outlets downstream of an annular flame trap through which combustion air is admitted to the combustion chamber from an air cushion chamber. These features increase the amplitude of the combustion cycle and reduce the amount of residual flame in the combustion chamber, resulting in a strong cycle. An air bypass pipe from the air cushion chamber to the exhaust pipe apparently increases the compression in the combustion chamber from the returning pressure waves. The deydration apparatus further includes a rotary drum into which material is to be dehydrated is delivered in the exhaust gas stream from the exhaust pipe of the pulse combustor.

Abstract: A dehydrator for fluent materials includes a pulse combustor and a cyclone separator having a cylindrical cyclone chamber and a central gas discharge tube. The pulse combustor has a finned tail pipe which is contained within a casing disposed generally tangentially to a cylindrical wall of the cyclone chamber. Material to be dried is introduced into the tail pipe and is discharged in a spiral pattern that flows downwardly around the gas discharge tube. Material in the gas stream falls into a collection hopper below the cyclone chamber. Gases leave through the gas discharge tube. In an alternative embodiment, a simpler dried material collection chamber is used.

Abstract: Various improvements in pulsating combustors for use in dehydration are disclosed. In one aspect of the invention, gas is introduced into the combustion chamber through a fuel distributor providing a bluff body within the combustion chamber so that a striated charge having streaks of gas and air is produced. The tail pipe of the combustor has an enlarged outer portion provided with an inlet for material to be dehydrated so that an injector action occurs at the point of material entry. A valve may be associated with the material inlet so that the material is introduced in timed relation to the pulse combustion cycle. Other aspects of the invention concern a rotary mechanically driven air admitting valve for the combustion chamber and a gas supply arrangement designed to provide for low- and high-fire operating modes.

Abstract: A pulse combustion apparatus capable of operating using a variety of different fuels includes an exchangeable fuel supply nozzle disposed adjacent a primary air inlet valve and separated from secondary air inlet valves by baffle means. The baffle means co-operates with the nozzle to define a metering orifice through which the primary air flows. The size of the orifice is determined by the axial position of the nozzle so that nozzles for different fuels can be positioned in axially different positions to meter the primary air as required to maintain continuous combustion commensurate with a pulse cycle of reasonable strength.

Abstract: A pulse combustion apparatus in which combustion air is brought into heat exchange relationship with the exhaust system of the apparatus for preheating the combustion air prior to entering the combustion chamber. In a preferred embodiment this is achieved by passing the combustion air through a space between an exhaust cushion chamber of the exhaust system and a housing which encloses the chamber.

Abstract: A heater, particularly for emergency use in a car or other vehicles is designed to use solid paraffin wax fuel. The heater has a housing containing a combustion chamber and burner. A vent duct is angled outwardly from the housing and both provides combustion air and permits exhaust of combustion products. The vent duct can be inserted through a window opening in a vehicle so that interior air is not consumed or contaminated when the heater is in operation.

Abstract: A pulse combustion apparatus in which combustion air is brought into heat exchange relationship with the exhaust system of the apparatus for preheating the combustion air prior to entering the combustion chamber. In a preferred embodiment this is achieved by passing the combustion air through a space between an exhaust cushion chamber of the exhaust system and a housing which encloses the chamber.

Abstract: The disclosure relates to pulse combustion apparatus generally and to air furnaces of the pulse combustion type. In one aspect, the invention provides a furnace which includes a combustion chamber and an exhaust system disposed in a passageway for air to be heated. The exhaust system includes a primary exhaust pipe, a manifold to which the primary exhaust pipe is coupled, and a plurality of heat exchange pipes which extend from the manifold across the air passageway. The primary exhaust pipe, manifold and heat exchange pipes form a reasonant system with the combustion chamber so that the ignition of successive fuel charges in the chamber causes pressure waves to oscillate throughout said exhaust system including the heat exchange pipes for promoting transfer of heat from the pipes to air flowing through the passageway in use.

Abstract: A pulse combustion heater is described and includes a combustion chamber and at least one exhaust pipe forming a resonant system with a chamber. In one aspect of the invention, the combustion chamber has an internal cavity of flattened spherical shape which causes combustion gases returning to the combustion chamber to flow into said cavity in a double toroidal flow pattern. In another aspect, the apparatus has an exhaust system which includes a primary exhaust pipe of a length selected so that combustion of gases is at least substantially complete before the gases leave the pipe. The pipe terminates at a manifold to which is connected a plurality of heat exchange coils of helical shape from which heat is transferred to a fluid circulated around the coils.

Abstract: A pulse combustion heater is described and includes a combustion chamber and at least one exhaust pipe forming a resonant system with the chamber. In one aspect, the heater has a three part housing, upper and lower parts of which are concrete castings and define respectively an air cushion chamber and an exhaust chamber of the heater. A center section forms part of a boiler sub-assembly which isolates the exhaust chamber from the air cushion chamber. In another aspect, a unitary gas cushion chamber sub-assembly is described.