The present subject matter relates to a smoke tube boiler including: a mix chamber, a heat exchanger, a firing rod assembly, a sealing means, and an air-cooled cooling means and a water-cooled cooling means.

The present invention relates to a finless-type dual-pipe heat exchange apparatus, and to a finless-type dual-pipe heat exchange apparatus capable of dually performing heat exchange inside and outside a heat exchange pipe so as to increase a heat transfer area and heat exchange efficiency. To this end, the finless-type dual-pipe heat exchange apparatus according to the present invention has a heat exchange pipe provided as a finless-type dual pipe such that exhaust gas moves to a secondary heat exchange space, formed inside a hot water tank, along an inner pipe passage while flames generated from a burner first heats an inner pipe of the finless-type dual pipe so as to perform a primary heat exchange, and simultaneously, an exhaust gas passage is formed to pass through a chamber, first heated by the flames generated from the burner, between both the chambers to which the inner pipe and an outer pipe are connected, in order to increase the heat exchange efficiency of the present apparatus, such that the exhaust gas is sent to the secondary heat exchange space formed inside the hot water tank and meets the exhaust gas flowing in through an exhaust gas passage of the inner pipe so as to uniformly transfer heat to the secondary heat exchange space formed inside the hot water tank, thereby performing a secondary heat exchange with the outer pipe of the heat exchange apparatus.

An oil boiler includes an outer container having openings at opposite ends, a combustion chamber that covers an opening at an upper end of the outer container and in which a combustion reaction occurs, a lower cover that covers an opening at a lower end of the outer container, a plurality of flue tubes to heat heating water flowing in the outer container by guiding combustion gas, a burner including a fuel nozzle that sprays fuel, an air nozzle that injects air, and a spark plug that ignites a mixture of the fuel and the air, and a flame tube part that defines a tube space by surrounding a partial space in which the mixture is ignited, the flame tube part including a flame tube having an open lower end and a recirculation hole formed through the flame tube such that the combustion gas is introduced into the flame tube.

A diffuser plate for a thermal transfer device can include a body having a number of first apertures and a second aperture that traverse therethrough, where the first apertures are asymmetrically arranged with respect to the second aperture. The first apertures can have a first shape and a first size, and where the first apertures are configured to receive a plurality of tubes. The second aperture has a second size, where the second size is larger than the first size.

A diffuser plate for a thermal transfer device can include a body having a number of first apertures and a second aperture that traverse therethrough, where the first apertures are asymmetrically arranged with respect to the second aperture. The first apertures can have a first shape and a first size, and where the first apertures are configured to receive a plurality of tubes. The second aperture has a second size, where the second size is larger than the first size.

A heat exchanger having a circulation guide, the heat exchanger comprising: a heat exchanger body; an inlet port, which is connected to a bottom end of the heat exchanger body; a discharge port which is connected to a top end of the heat exchanger body; a top body tube installed at a top end of an inside of the heat exchanger body; a bottom end plate installed at a bottom end of the inside of the heat exchanger body; and combustion pipes, which each have a top end connected to pass through a floor surface of the top body tube.

A heat exchanger having a circulation guide, the heat exchanger comprising: a heat exchanger body; an inlet port, which is connected to a bottom end of the heat exchanger body; a discharge port which is connected to a top end of the heat exchanger body; a top body tube installed at a top end of an inside of the heat exchanger body; a bottom end plate installed at a bottom end of the inside of the heat exchanger body; and combustion pipes, which each have a top end connected to pass through a floor surface of the top body tube.

The purpose of the present invention is to provide a smoke tube boiler which can prevent leakage of mixed gas and exhaust gas through a gap between a mix chamber and an ignition bar assembly. To this end, the smoke tube boiler according to the present invention comprises: a mix chamber having a mixing space, in which a combustion gas and air are mixed, and a flat plate type burner, the mix chamber being disposed on the upper side of a combustion chamber; an ignition bar assembly assembled to pass through one side of the mix chamber and extending across the upper portion of the combustion chamber to the lower side of the flat plate type burner; and a sealing means for preventing the mixed gas in the mixing space and an exhaust gas in the combustion chamber from leaking to the outside through a gap between the mix chamber and the ignition bar assembly.

The purpose of the present invention is to provide a smoke tube boiler which can prevent leakage of mixed gas and exhaust gas through a gap between a mix chamber and an ignition bar assembly. To this end, the smoke tube boiler according to the present invention comprises: a mix chamber having a mixing space, in which a combustion gas and air are mixed, and a flat plate type burner, the mix chamber being disposed on the upper side of a combustion chamber; an ignition bar assembly assembled to pass through one side of the mix chamber and extending across the upper portion of the combustion chamber to the lower side of the flat plate type burner; and a sealing means for preventing the mixed gas in the mixing space and an exhaust gas in the combustion chamber from leaking to the outside through a gap between the mix chamber and the ignition bar assembly.

A tube for a thermal transfer device can include at least one wall having an inner surface and an outer surface, where the inner surface forms a cavity. The inner surface can be non-cylindrical. The cavity can be configured to receive a fluid that flows continuously along a length of the at least one wall.