Patent Application
20190293320
The invention relates to an extreme condensing boiler, more specifically to an extreme condensing boiler, which adopts heat-exchanging structure with triple-tubing or double-tubing tube including an inner tube (fire tube), a middle tube (cold water), and an outer tube (hot water), and in which cold water descends through a cold water header and is turned into medium-hot water, and the medium-hot water ascends again and absorbs heat from around it and is turned into hot water, to be supplied to a hot water header, so that the temperature of exhaust gas is lowered and carbon emission is minimized by absorbing waste heat from the exhaust gas, preventing the global warming by air pollution and maximizing the thermal efficiency through harvesting heat on both sides.
In general, a boiler used for supplying heating and supplying hot water in houses can be categorized into a regular boiler and a condensing boiler according to how to retrieve combustion heat for heating water.
All the conventional condensing boilers includes a sensible heat exchanger for producing hot water with heat for heating water and a separate waste-heat heat exchanger for retrieving latent heat of vapor in the exhaust gas.
The heat exchanger (CORE) used in modern boilers including condensing boilers and regular boilers includes a single tube structure of water tube or fire tube type.
The single tube type boiler was invented in the period of British Industrial Revolution in the Eighteenth century, uses a heat exchanger (CORE) developed to use coal, firewood, etc. for fuel, and therefore is a 300 years old device having a very low efficiency of absorbing heat.
Since high combustion rate fuel such as petroleum, LNG-gas, etc. is used in the single tube type boiler developed for fuel such as coal, firewood, etc. and heat of high temperature is supplied by powerful burners with air blower for supplying huge amount of combustion air in order to increase fuel efficiency, lots of thermal energy that the three centuries old single tube type of heat exchanger could not retrieve is released into the atmosphere, wasting a lot of energy and causing the global warming with air pollution through emitting exhaust gas of high temperature, especially, carbon dioxide (CO2).
According to environment research organizations that investigate factors causing the global warming, the exhaust gas from boilers is more responsible for the air pollution and the global warming than exhaust gas from automobiles.
Therefore, a need for extreme condensing boilers of new concepts has been present for conserving fast-repleting fossil fuel, preventing the global warming, and protecting the environment through renovating the structure of the single tube type boilers from the 18th century.
Related technology includes Korean Patent No. 10-1196913 (Oct. 26, 2012, Title of Invention: “Hot water storage type PID control condensing boiler”).
The present invention contrives to solve the disadvantages of the prior art, and is to provide an extreme condensing boiler, which has a slim and tall module structure, and adopts heat-exchanging structure with triple-tubing or double-tubing tube including an inner tube (fire tube), a middle tube (cold water), and an outer tube (hot water), and in which cold water descends through a cold water header and is turned into medium-hot water, and the medium-hot water ascends again and absorbs heat from around it and is turned into hot water, to be supplied to a hot water header, so that the temperature of exhaust gas is lowered and carbon emission is minimized by absorbing waste heat from the exhaust gas, preventing the global warming by air pollution and maximizing the thermal efficiency through harvesting heat on both sides.
In order to achieve the above goals, an extreme condensing boiler according to the invention comprises: a cold water header provided in an upper portion of a main body and configured for receiving and distributing cold water to a plurality of cold water supply tubes; a hot water header provided in a lower portion of the cold water header and configured for receiving and discharging hot water to an outside; a burner provided in a lower portion of the main body and configured for generating heat; a multi-tubing heat exchanger configured so that cold water goes down therethrough, absorbs heat from exhaust gas of the burner, and is heated to medium-hot water, and then the medium-hot water rises therethrough, absorbs the heat generated by the burner, and is heated to hot water, through absorbing heat from both sides of corresponding tube portion of the multi-tubing heat exchanger, and then the hot water is delivered to the hot water header; and a combustion air heat exchanger provided around the multi-tubing heat exchanger in the main body, so as to provide the combustion air to the burner in a top to bottom direction.
Also, in the above extreme condensing boiler, the multi-tubing heat exchanger comprises: an inner tube (fire tube) disposed so as to penetrate up to a top portion of the cold water header, be connected to a top portion of the burner, and deliver therethrough and discharge the exhaust gas to a exhaust flue; a middle tube disposed around the inner tube (fire tube) with a first interval, connected to the cold water header, and configured for delivering cold water stored in the cold water header to a bottom portion thereof, absorbing heat from the exhaust gas rising in the inner tube (fire tube) and latent heat of vapor contained in the exhaust gas, and converting the cold water to the medium-hot water; and an outer tube disposed around the middle tube with a second interval, including a top portion connected to the hot water header and a bottom portion fixed to a perimeter of a bottom portion of the inner tube (fire tube), so as to revert and deliver the medium-hot water discharged from the middle tube upwards therethrough, convert the medium-hot water to hot water with the heat from the burner in a fire chamber of the burner, and deliver the hot water to the hot water header.
Also, the a bottom plate of the hot water header is formed by bending in a shape of a circular arc, so as to guide the heat generated by the burner to be applied to the bottom plate of the hot water header and guide from a center of the bottom plate toward an edge portion so as to fall downwards, and a condensate water collecting plate is provided at a lower portion of the burner, which is configured to collect condensate water produced in the extreme condensing boiler therein, and a condensate water discharging pump (SUMP PUMP) is provided in the condensate water collecting plate, which is configured to discharge the collected condensate water to outside.
Also, the combustion air heat exchanger comprises: a heat-exchanging flue exposed to the top portion of the main body so as to be installed around the exhaust flue and configured to absorb the combustion air from the outside and absorb heat from the exhaust gas in the exhaust flue; a combustion flue extending downwards from the heat-exchanging flue and configured to heat the combustion air with waste heat in the fire chamber connected to the bottom portion of the main body through the cold water header, the hot water header, and the perimeter of the multi-tubing heat exchanger; and a combustion air supplier provided in a lower portion of the combustion flue and configured to supply the falling combustion air to the burner.
Also, the heat-exchanging flue is formed in a shape of bellows and connected with the exhaust flue, so as to absorb heat from the exhaust gas, increasing an efficiency of heat-exchanging, and the combustion flue is formed with repetitive protruding portions and receding portions, so as to absorb heat from the fire chamber and the exhaust gas, increasing a temperature of the combustion air, and an insulator is provided around the combustion flue for insulation.
Also, the heat-exchanging flue uses the atmospheric pressure and Coriolis force, so that the combustion air taken in from around the heat-exchanging flue descends with a whirlwind rotation (counterclockwise) and heat-exchanges with heat of exhaust gas rotating (clockwise) and ascending in the heat-exchange flue and heat from the fire chamber, supplying hot combustion air to the burner and increasing the combustion efficiency and at the same time minimizing a temperature of the exhaust gas.
An extreme condensing boiler according to the invention has a slim and tall module structure and adopts heat-exchanging structure with triple-tubing or double-tubing tube including an inner tube (fire tube), a middle tube (cold water), and an outer tube (hot water), and in which cold water descends through a cold water header and is turned into medium-hot water, and the medium-hot water ascends again and absorbs heat from around it and is turned into hot water, to be supplied to a hot water header, and if necessary, through adding components and partial structural modification, they can be manufactured and used for industrial and power generating high pressure steam boilers.
With the selection of diameter of copper pipe or steel pipe for heat exchanger, it can be manufactured in small size for house, middle size for commercial and big size industries, etc. for all usages and capacities, and since it is slim and tall, large-sized boilers for industries and power generation can be made to be inserted in a chimney and installed at a lower portion of the chimney.
Since it can be installed easily in a chimney, it may be a boiler of new concepts and a future type, in which a installation space can be saved a lot.
Since it can harvest waste heat as much as possible and minimize the temperature of exhaust gas, it is possible to prevent the global warming and conserve the fossil fuels such as fast-depleting coal and petroleum.
It may be applied to heating, industrial use, power generation, ships, etc., and has been developed for introduction of high-tech and innovating extreme condensing boilers, which is necessary for the era of climate change and global warming.
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Below, referring to the figures, an extreme condensing boiler according to an embodiment of the invention is described.
In the description or explanation, the thickness of lines, sizes of components, etc. may be exaggerated for clarity and convenience. Also, the terms have been defined considering functions in the invention, and they can be changed according to the intention and tradition of users and operators. Therefore, the definition of such terms must be decided based on the entire contents of this specification.
Referring to
The cold water header (100) is provided inside and at a top portion of a main body (10), and comprises a plurality of tubes. The cold water header (100) is provided with a plurality of cold water supply tubes (110).
The top portion of the cold water header (100) is formed by bending in a shape of circular arc.
Since cold water stored in the cold water header (100) descends or falls downwards and absorbs heat for heating that rises upwards and waste heat of vapor in exhaust gas, the cold water is turned into medium-hot water as descending downwards.
The hot water header (200) is provided at a lower portion of the cold water header (100), and has a structure for being provided with hot water and discharging the hot water to places of usages. The hot water header (200) includes a hot water discharge tube, or domestic hot water discharge (210).
A outer bottom plate (230) corresponding to a bottom of the hot water header (200) is formed with a circularly arc plate body that is convex upwards.
The outer bottom plate (230) performs a function of guiding heat rising in a fire chamber, or combustion heat ascending and descending gap (560) by a burner (300) from a central portion to an edge portion.
The burner (300) has a structure or is configured for being disposed at the bottom of the main body (10) and generating heat of high temperature.
The burner (300) is installed in a bottom space of the main body (10) and used as a heating device for providing flame to the multi-tubing heat exchanger (400).
At the lowest end of the hot water header (200) is provided a discharging valve (220) for discharging to outside precipitate including lime in water or caused in using hot water.
Since the edge portion of the outer bottom plate (230) is formed with lower step than the central portion of the outer bottom plate (230), the discharging valve (220) is preferably formed at a side of the hot water header (200) that is close to the outer bottom plate (230), which is more efficient for hot water usage and discharging of precipitate.
In the hot water header (200) is provided a high-temperature high-pressure relief valve (240), so that if high temperature and high pressure take place in the hot water header (200), it is configured to be released to outside for safety.
The high-temperature high-pressure relief valve (240) may be operated manually by a user's opening or closing it, or automatically through a controller by detecting high temperature and high pressure.
The high-temperature high-pressure relief valve (240) may be preferably provided at a side of the hot water header (200).
At a side of the hot water header (200) may be provided a temperature sensor (310) for sensing optimal temperature of hot water.
The gas control valve (320) may be operated in a mode of ratio control.
The temperature sensor (310) may control a gas control valve (320) to control the supply amount of gas, oil, etc. supplied through the fuel supply (330), maintaining an optimal temperature of the hot water header (200).
The gas control valve (320) is provided at a path of the fuel supply (330).
The open-closing amount of the gas control valve (320) is controlled by the temperature sensor (310) detecting temperature of the hot water header (200), controlling the flame of the burner (300) and maintaining an optimal temperature of the hot water header (200).
When the temperature in the hot water header (200) is above a preset temperature (75° C., for an example), the temperature sensor (310) detects that the temperature of the hot water header (200) is too high, and closes (OFF) the gas control valve (320) through a controller, lowering the temperature of hot water.
On the other hand, when the temperature in the hot water header (200) is below a preset temperature (50° C., for an example), the temperature sensor (310) detects that the temperature of the hot water header (200) is too low, and opens (ON) the gas control valve (320) through a controller, raising the temperature of hot water.
There, if the temperature of the hot water header (200) is above a preset temperature (higher than 120° C., for an example), then the extreme condensing boiler according to the invention may be used as a high pressure steam condensing boiler.
As in the above, since the temperature of hot water is maintained at an optimal temperature by controlling the flame of the burner (300) through ratio control between the temperature sensor (310) and the gas control valve (320), it is possible to prevent discharging exhaust heat by overheating and to conserve fuel.
The multi-tubing heat exchanger (400) is configured, so that cold water of the cold water header (100) descends and absorbs exhaust heat and waste heat so as to converting to medium-hot water, and the medium-hot water is ascended again so as to absorb heat generated by the burner (300) so as to convert hot water through both-side heat absorbing and delivering and supplying to the hot water header (200).
The multi-tubing heat exchanger (400) is applied with double-tubing and triple-tubing together so as to convert cold water to hot water, in which the double-tubing is applied to the bottom section of the outer bottom plate (230) of the hot water header (200) and the cold water header (100), and the triple-tubing is applied to the top section of the outer bottom plate (230) of the hot water header (200) and the burner (300).
The multi-tubing heat exchanger (400) includes an inner tube (410) that penetrates the top side of the cold water header (100) and is connected to the top portion of the burner (300), raising exhaust gas and discharging to an exhaust flue (440), a middle tube (420) installed around the inner tube (410) with an interval and connected to the cold water header (100), delivering cold water stored in the cold water header (100) downwards so as to absorb exhaust heat ascending in the inner tube (410) and waste heat of vapor contained in the exhaust gas and convert cold water to medium-hot water, and an outer tube (430) installed around the middle tube (420) with an interval having a top side connected to the hot water header (200) and a bottom side fixed to a perimeter of the bottom portion of the inner tube (410) so as to revert and delivering upwards the medium-hot water discharged from the middle tube (420) and converting to hot water in the fire chamber or combustion heat ascending and descending gap (560) by heat of the burner (300) and delivering to the hot water header (200).
The outer bottom plate (230) of the hot water header (200) is formed in a shape of circular arc and configured to guide heat generated at the burner (300) and ascending to hit the bottom center and then toward the perimeter, so as to descend.
The heat whose temperature is lowered relatively descends through a space formed around by convection by temperature difference, ascends again at the bottom end of the heat exchanger through a plurality of fire tubes, and heats the descending cold water and retrieves the waste heat of the exhaust gas.
The heat-exchanging tubes are arranged in a hexagonal shape, forming heat-descending spaces (580) at six portions around the fire chamber or combustion heat ascending and descending gap (560), so that the heat descends fluently, ascends again through the exhaust flue to be used as a heat source to heat cold water, which is enabled by natural convective circulation.
As shown in
At a lower portion of the burner (300) is provided a condensate water collector (340) configured for collecting and discharging condensate water produced in the condensing boiler.
In the condensate water collector (340) may be provided a condensate water discharger (350) for discharging the collected condensate water to outside.
It performs a function of discharging condensate water produced in the combustion air supply (530) and the fire tube of the multi-tubing heat exchanger.
Referring to
The exhaust flue (440) is formed on an exterior surface of each of the tubes in a shape of protruding pin and fixes the position of each of the inner tube (410), the middle tube (420), and the outer tube (430), maintaining the intervals in the double-tubing or triple-tubing structure.
In order to increase the heat-absorbing efficiency and according to the diameter of tube, 3, 6, 8, or more spacers (450) may be formed on the exterior surface of the tube.
The condensate water collector (340) may be formed so as to bulge downwards gradually as going toward both centers.
The condensate water collector (340) collects condensate water including acid water (below PH 3.5) containing pollutants such as sulfur oxide (SOx) and nitrogen oxide (Nox) and discharges at once, preventing discharging of pollutants and pollution and lengthening the life of boiler through preventing corrosion by condensate at the bottom of the boiler.
In the main body (10) may be provided a seismic strap (600) configured for preventing damage to the condensing boiler by earthquake and gas reak.
The seismic strap (600) is provided so as to enclose the main body (10) of the condensing boiler, and both end portions are installed fixedly to a wall, protecting the main body (10).
The combustion air heat exchanger (500) is provided around the multi-tubing heat exchanger (400) in the main body (10), so as to supply combustion air to the burner from the top to the bottom.
The combustion air heat exchanger (500) comprises a heat-exchanging flue (510) that is exposed to the top side in the main body (10) and installed around the exhaust flue (440), takes in combustion air from outside, and absorbs the exhaust heat of the temperature sensor (310), an combustion flue (520) extending downwards from the heat-exchanging flue (510), connected to the bottom portion of the main body (10) through around the cold water header (100), the hot water header (200), and the multi-tubing heat exchanger (400), and heats the combustion air in the combustion air gap or outdoor air descending gap (570) with radiating heat (waste heat) of the fire chamber or combustion heat ascending and descending gap (560), and an combustion air supply (530) provided in a lower portion of the combustion flue (520) and supplying the heated combustion air to the burner (300).
The heat-exchanging flue (510) is connected to the exhaust flue (440) through bellows, so as to absorb heat from the exhaust gas, increasing the heat-exchanging efficiency.
The combustion air heat exchanger (500) is formed with repetitive protruding portions and receding portions, absorbs heat of the fire chamber or combustion heat ascending and descending gap (560) and from exhaust heat, and raises the temperature of the combustion air.
Around the combustion air heat exchanger (500) may be provided an insulator (540) for preventing radiating heat.
The insulator (540) may be formed so as to enclose the entire section from top to bottom of the main body (10) or a partial section.
On the exterior surface of the insulator (540) my be provided an outer case (550) for protecting the insulator (540) and the like. The outer case (550) is formed with metal plate of cylindrical shape.
As in the above, the combustion air descends through the combustion air heat exchanger (500) while absorbing exhaust heat and increasing temperature, and at the same time the exhaust gas loses its heat to the combustion air, so that the carbon emission can be reduced drastically and therefore it is possible to reduce the air pollution and prevent the global warming.
On the other hand, referring to
By the Coriolis's force, the cold combustion air rotates counterclockwise and descends (high density), and the hot exhaust gas rotates clockwise and ascends (low density), so as to obtain mutual heat exchanging.
The heat-exchanging flue (510) may be manufactured as bellows of aluminum foil with high thermal conductivity, so as to expand the heat-exchanging surface, optimizing the heat-exchanging function.
Since the heat-exchanging flue (510) performs heat-exchanging through combustion air and exhaust gas that whirlwind in opposite directions, the time for heat-exchanging is extended and the heat-exchanging efficiency can be maximized.
As in the above, since the combustion efficiency can be increased by pre-heating cold combustion air, the carbon emission can be reduced by absorbing heat from the exhaust gas, and if applying to the vent of high chimneys of industrial or power-generating large-sized boiler, the reduction of exhaust temperature is further facilitated, it is possible to reduce the air pollution and the global warming.
The extreme condensing boiler according to the invention may be manufactured into a small-sized home boiler or a mid-sized commercial boiler and a large-sized industrial and power-generating condensing boiler with selecting diameter of tube size and increasing the length of heat exchanger.
Since the chimney of industrial and power-generating boiler is high, the exhaust temperature of hundreds of degrees in Celsius in power-generating boiler can be minimized using a large-sized Coriolis vent made of aluminum.
According to the Paris Climate Change Agreement (December 2015) among 195 countries for preventing the global warming and reducing carbon emission, the usage of condensing boiler of high efficiency has been obliged in all the industrialized countries.
Since the extreme condensing boiler according to the invention can be manufactured by selecting three for each diameter out of ½ to 10 inches of copper tubes or steel tubes according to the boiler capacity, it is possible to manufacture boilers from small size to large size for apply to residential, commercial, industrial and power generation.
While the invention has been shown and described with reference to different embodiments thereof, it will be appreciated by those skilled in the art that variations in form, detail, compositions and operation may be made without departing from the spirit and scope of the invention as defined by the accompanying claims.
Another aspect of the invention provides an extreme condensing boiler comprising a first cold water header (100), a domestic hot water header (200), a second cold water header (100A), a hydro heating hot water header (200A), a burner (300), a plurality of multi-tubing heat exchangers (400), a combustion air heat exchanger (500), an inner bottom plate (230A), and a flame divider (390).
The first cold water header (100) is provided in an upper outer portion of a main body (10) and configured for receiving from a cold water supply tube (110) and distributing cold water to cold-water down gaps (420T) of an outer group of a plurality of multi-tubing heat exchangers.
The domestic hot water header (200) is provided in a lower portion of the first cold water header (100) and configured for receiving from hot-water up gaps (430T) of the outer group of the plurality of multi-tubing heat exchangers and discharging domestic hot water to an outside, or domestic hot water discharge (210).
The second cold water header (100A) is provided in an upper inner portion of the main body (10) and configured for receiving from a cold water supply tube (110A) distributing cold water to cold-water down gaps (420T) of an inner group of the plurality of multi-tubing heat exchangers.
The hydro heating hot water header (200A) is provided in a lower portion of the second cold water header (100A) and configured for receiving from hot-water up gaps (430T) of the inner group of the plurality of multi-tubing heat exchangers and discharging hydro heating water to an outside, or hydro heating water discharge (210A).
The burner (300) is provided in a lower portion of the main body and configured for generating heat, and comprises an inner burner (300A) disposed in a central portion for a lower header and an outer burner (300) for an upper header disposed around the inner burner (300A).
Each of the plurality of multi-tubing heat exchangers (400) is configured so that cold water goes down therethrough, absorbs heat from exhaust gas of the burner, and is heated to medium-hot water, and then the medium-hot water rises therethrough, absorbs the heat generated by the burner, and is heated to hot water, through absorbing heat from both sides of corresponding tube portion of the multi-tubing heat exchanger, and then the hot water is delivered to the domestic hot water header (200) and the hydro heating water header (200A), and the outer group of the plurality of multi-tubing heat exchangers disposed in a outer portion are configured to heat water for the domestic hot water header (200) and the inner group of the plurality of multi-tubing heat exchangers are configured to heat water for the hydro heating hot water header (200A).
The combustion air heat exchanger (500) is provided around the plurality of multi-tubing heat exchangers (400) in the main body, so as to provide the combustion air to the burner in a top to bottom direction.
The inner bottom plate (230A) of the hydro heating water header (200A) and an outer bottom plate (230) of the domestic hot water header (200) are formed by bending in a shape of a circular arc, so as to guide the heat generated by the burner to be applied to the bottom plate of the hydro heating water header and guide from a center of the bottom plate toward an edge portion so as to fall downwards, and a condensate water collecting plate (340) is provided at a lower portion of the burner, which is configured to collect condensate water produced in the extreme condensing boiler therein, and a condensate water discharger (350) is provided in the condensate water collecting plate, which is configured to discharge the collected condensate water to outside.
The flame divider (390) is provided below the inner bottom plate (230A) and between flames of the inner and outer burners (300A, 300) and configured to divide inner flames and outer flames.
The first cold water header (100) and the domestic hot water header (200) are separated by an outer horizontal separation wall (720).
The second cold water header (100A) and the hydro heating water header (200A) are separated by an inner horizontal separation wall (720A).
The first cold water header (100) and the second cold water header (100A) are separated by a vertical separation wall (710), and the domestic hot water header (200) and the the hydro heating hot water header (200A) are separated by the vertical separation wall (710).
The combustion air heat exchanger (500) comprises a heat-exchanging flue (510), a combustion flue (520), and a combustion air supplier (530).
The heat-exchanging flue (510) is exposed to the top portion of the main body so as to be installed around the exhaust flue and configured to absorb the combustion air from the outside and absorb heat from the exhaust gas in the exhaust flue.
The combustion flue (520) extends downwards from the heat-exchanging flue and configured to heat the combustion air with waste heat in the fire chamber connected to the bottom portion of the main body through the cold water header, the hot water header, and the perimeter of the multi-tubing heat exchanger.
The combustion air supplier (530) is provided in a lower portion of the combustion flue and configured to supply the falling combustion air to the burner.
The inner burners and the outer burners are configured to operate separately, individually, or together.
Each of the plurality of multi-tubing heat exchangers may comprise an inner tube (fire tube), a middle tube, and an outer tube.
The inner tube (fire tube) is disposed so as to penetrate up to a top portion of the first cold water header (100) and the second cold water header (100A), be connected to a top portion of the burner, and deliver therethrough and discharge the exhaust gas to a exhaust flue.
The middle tube is disposed around the inner tube with a first interval, connected to the first and second cold water headers up to the horizontal separation wall (720), and configured for delivering cold water stored in the first cold water header to a bottom portion thereof, absorbing heat from the exhaust gas rising in the inner tube and latent heat of vapor contained in the exhaust gas, and converting the cold water to the medium-hot water.
The outer tube is disposed around the middle tube with a second interval, includes a top portion connected to the domestic hot water header (200) and the hydro heating water header (200A) and a bottom portion fixed to a perimeter of a bottom portion of the inner tube, so as to revert and deliver the medium-hot water discharged from the middle tube upwards therethrough, convert the medium-hot water to hot water with the heat from the burner in a fire chamber of the burner, and deliver the hot water to the hot water header.
The heat-exchanging flue (510) is formed in a shape of bellows and connected with the exhaust flue, so as to absorb heat from the exhaust gas, increasing an efficiency of heat-exchanging.
The combustion flue is formed with repetitive protruding portions and receding portions, so as to absorb heat from the fire chamber and the exhaust gas, increasing a temperature of the combustion air.
An insulator is provided around the combustion flue for insulation.
In
The ascending heat from the burner ascends through the central portions (590, 590A) and is guided to the peripheral portion (580) at the bottom surface of the bent header, so that most of the heat descends and then ascends through the fire tube at the bottom, and a portion of the heat ascends through a gap (500) formed so as to surround the headers (hot and cold), pre-heating the descending cold combustion air, heating the exterior surface of the header, and then being exhausted.
Thus, the scope of the invention must be determined by the accompanying claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2018-0033867 | Mar 2018 | KR | national |
