In a primary heat exchanger, a heat conduction pipe is arranged as one connected pipe in a lower stage and an upper stage in a manner extending back and forth through a plurality of fins. The heat conduction pipe is arranged such that a pitch between the heat conduction pipes in the upper stage is shorter than a pitch between the heat conduction pipes in the lower stage. In addition, the heat conduction pipe is arranged such that a position in a center of each heat conduction pipe in the upper stage in a second direction orthogonal to a first direction in which the heat conduction pipe extends and a position in a center of each heat conduction pipe in the lower stage in the second direction are displaced from each other.

A combustion apparatus includes a burner (11), a heat exchanger (12) accommodated in a casing (20), an exhaust passage (22B) provided to one side surface side of the casing (20), and an exhaust resistance member (5) having a plurality of ventilation ports (50) through which combustion exhaust gas passes, wherein at least one part of the ventilation ports (50) has an elongated hole shape extending in the flow direction of the combustion exhaust gas from beneath the casing (20) to the exhaust passage (22B).

A condensate trap for a furnace system includes a trap inlet configured to receive combusted gases, a condensate chamber coupled to the trap inlet and configured to trap condensate, a trap outlet coupled to the condensate chamber and configured to exhaust the combusted gases, a header box inlet configured to receive condensate from a header box, and a condensate outlet configured to drain condensate from the condensate chamber. Combusted gas that passes through the condensate trap provides heat to condensate within the condensate trap to thaw frozen condensate or to prevent condensate from freezing.

A water heater includes a burner generating combustion gas, a heat exchanger heating water which flows through the inside, through heat exchange with combustion gas generated in the burner, a fan supplying air to the burner, and a housing storing these components. The water heater has a water entry portion in a top plate of the housing. A water supply pipe for supplying water to the inside of the heat exchanger is connected to the water entry portion. The water entry portion is arranged to be included, in a plane view, in at least one component constituting the heat exchanger and an exhaust path for combustion gas which has passed through the heat exchanger. The component is made of a material having corrosion resistance against drainage water resulting from condensation of combustion gas.

A heat exchanger for supplying heat includes a housing, a bundle of helical fin-coil tubes, and a flue channel. The housing includes a burner, a water inlet, a water outlet and a flue gas outlet. The burner is disposed on a top portion of the housing and connected to an air/gas mixture unit. The bundle of helical fin-tube coils is disposed tightly, circularly, and coaxially around the burner. The flue channel is disposed below the burner and is formed by a plurality of serpentine bent fin-tube coils. A flow of flue gas vents from the flue channel to the flue gas outlet. The water inlet is connected to the plurality of serpentine bent fin-tube coils which forms the flue channel below the burner. The plurality of serpentine bent fin-tube coils below the burner are connected to the bundle of helical fin-tube coils. The bundle of helical fin-tube coils are connected to the water outlet.

A heat exchanger for supplying heat includes a housing, a bundle of helical fin-coil tubes, and a flue channel. The housing includes a burner, a water inlet, a water outlet and a flue gas outlet. The burner is disposed on a top portion of the housing and connected to an air/gas mixture unit. The bundle of helical fin-tube coils is disposed tightly, circularly, and coaxially around the burner. The flue channel is disposed below the burner and is formed by a plurality of serpentine bent fin-tube coils. A flow of flue gas vents from the flue channel to the flue gas outlet. The water inlet is connected to the plurality of serpentine bent fin-tube coils which forms the flue channel below the burner. The plurality of serpentine bent fin-tube coils below the burner are connected to the bundle of helical fin-tube coils. The bundle of helical fin-tube coils are connected to the water outlet.

Provided is a heat exchanger. The heat exchanger may include a plurality first through third heat exchange pipes connected between a first side part and a second side part, each of which comprising a path of moving heat-exchanger fluid inside; first blisters formed on the outer side surfaces of the first side part and the second side part, thereby connecting gaps between each neighboring first heat exchange pipe; second blisters formed on the outer side surface of the first side part, thereby connecting the first heat exchange pipes with the second heat exchange pipes or the second heat exchange pipes with the third second heat exchange pipes; and third blisters formed on the outer side surface of the second side part, thereby connecting neighboring second heat exchange pipes or neighboring third heat exchange pipes. The second heat exchange pipes may be spaced apart from the first heat exchange pipes and formed above the first heat exchange pipes and the third heat exchange pipes may be spaced apart from the second heat exchange pipes and formed above the second heat exchange pipes.

In a combustion apparatus that includes a heat exchanger which is disposed in a combustion box, on a premise that a direction from a burner to the heat exchanger is defined as a Z-axis plus direction, a direction opposite to the Z-axis plus direction is defined as a Z-axis minus direction, and an orthogonal direction to a Z-axis direction, which is along fins of the heat exchanger is defined as a X-axis direction, a thermal insulation material is arranged on an inner surface of a swelling part that is formed at a side plate part of a combustion box and outwardly swells in the X-axis direction so as to be sandwiched from both sides in the Z-axis direction by a step that is outwardly bent in the X-axis direction, which is positioned an end, in the Z-axis plus direction, of the swelling part and a structural member of a burner, which inwardly protrudes in the X-axis direction from an end, in the Z-axis minus direction, of the side plate part. A vicinity portion of an end, in the Z-axis plus direction, of the thermal insulation material is held from an inside in the X-axis direction by a side edge portion, on each side in the X-axis direction, of the fins.

A water heater includes a primary heat exchanger, a secondary heat exchanger disposed above the primary heat exchanger, a flow path member, and a flow restriction member. The secondary heat exchanger includes a case and heat transfer pipes arranged in the case. The case includes a wall having a gas inlet through which combustion exhaust gas discharged from the primary heat exchanger is introduced into the case. The flow path member connects the primary heat exchanger and the secondary heat exchanger and is disposed adjacent to the gas inlet and is configured to introduce the combustion exhaust gas discharged from the primary heat exchanger into the secondary heat exchanger through the gas inlet. The flow restriction member is disposed on the wall of the case to suppress upward flowing of the combustion exhaust gas that is introduced into the case through the gas inlet.

The invention relates to a device for cleaning the pipes of the drinking water circuit of an aircraft, in which the device is independent of the aircraft and is connected to the circuit intermittently and supplied with liquid. The device is characterized in that it comprises a mobile chassis supporting a plurality of functional sub-assemblies required to produce a hot liquid, including a closed-furnace gas condensing boiler. The invention can be used to clean the pipes of aircraft.