Patent Grant
11371695
The present application is made based on Japanese Patent Application No. 2019-207481 filed on Nov. 15, 2019 in Japan, Japanese Patent Application No. 2020-045123 filed on Mar. 16, 2020 in Japan, Japanese Patent Application No. 2020-126761 filed on Jul. 27, 2020 in Japan, and PCT/JP2019/041898 filed on Oct. 25, 2019, the entire contents thereof are incorporated herein by reference.
The present invention relates to a boiler.
Typically, a boiler has been broadly utilized for various purposes including industrial and commercial purposes. In the boiler, a heat generation unit configured to heat supplied fluid such as water or a heat medium is provided, and as one form of the heat generation unit, there is one provided with a heat generation body in a container.
There are various specific forms of the above-described heat generation unit, and as one example thereof, one including, in a container, a heat generation body (a reactant) configured such that multiple metal nanoparticles made of hydrogen storing metal or hydrogen storing alloy are formed on a surface has been disclosed as a heat generation system in Japanese Patent No. 6448074 (Patent Literature 1). According to Patent Literature 1, it has been described that in the heat generation system, hydrogen-based gas contributing to heat generation is supplied into the container to store hydrogen atoms in the metal nanoparticles and excess heat is generated.
Note that as also described in Patent Literature 1, an announcement that the heat generation body produced from palladium is provided in the container and heat generation reaction is made by heating the inside of the container while heavy hydrogen gas is being supplied into the container has been released. Moreover, regarding a heat generation phenomenon that the excess heat (an output enthalpy higher than an input enthalpy) is generated utilizing the hydrogen storing metal or the hydrogen storing alloy, details of the mechanism for generating the excess heat have been discussed among researchers of each country, and it has been reported that the heat generation phenomenon has occurred. Note that as a document regarding the present technical field, there is U.S. Pat. No. 9,182,365 (Patent Literature 2) in addition to Patent Literature 1.
It is important for the boiler configured to heat fluid by the heat generation unit including the heat generation body in the container to moderately heat fluid according to various situations while heat generated by the heat generation body can be efficiently utilized. For example, in a case where a steam amount (a steam load) required for the boiler from the outside varies, water heating needs to be reduced under a situation where the steam load is relatively low, and needs to be accelerated under a situation where the steam load is relatively high.
The present invention has been made in view of the above-described problems. An object of the present invention is to provide a boiler for heating fluid by a heat generation unit including heat generation bodies in a container, the boiler being configured so that fluid can be moderately heated according to various situations while heat generated by the heat generation bodies can be efficiently utilized.
The boiler according to the present invention is a boiler for heating fluid by using heat generated by a heat generation body, the boiler including the heat generation body and a container having the heat generation body inside and configured such that the inside of the container is filled with gas with higher specific heat than that of air. The boiler includes a controller configured to control a heat generation amount of the heat generation body under a situation where the gas has been supplied into the container. According to the present configuration, fluid is heated by a heat generation unit including the heat generation body in the container, and can be moderately heated according to various situations while heat generated by the heat generation body can be efficiently utilized. More specifically, as the above-described configuration, it may be configured such that the boiler includes, as a path for circulating the gas, a circulation path having, as part thereof, the inside of the container.
More specifically, as the above-described configuration, it may be configured such that the gas is hydrogen-based gas and the heat generation body is a reactant configured such that a metal nanoparticle made of hydrogen storing metals is provided on a surface and a hydrogen atom is stored in the metal nanoparticle to generate excess heat. Note that the hydrogen-based gas in the present application is heavy hydrogen gas, light hydrogen gas, or a combination thereof. Moreover, the “hydrogen storing metals” in the present application means hydrogen storing metal such as Pd, Ni, Pt, or Ti or hydrogen storing alloy containing one or more types of these metals.
More specifically, as the above-described configuration, it may be configured such that the boiler further includes a heater and the controller adjusts a gas circulation amount in the circulation path or the temperature of the heater to control the heat generation amount.
More specifically, as the above-described configuration, it may be configured such that the boiler further includes a burner and the controller adjusts the gas circulation amount in the circulation path or the temperature of the burner to control the heat generation amount. More specifically, as the above-described configuration, it may be configured such that the boiler further includes, as the burner, a hydrogen-powered burner configured to burn hydrogen-based gas and a common hydrogen-based gas supply source is provided for the hydrogen-powered burner and the inside of the container.
More specifically, as the above-described configuration, it may be configured such that the boiler supplies, to the outside, steam generated by heating of water as the fluid and the controller controls the heat generation amount based on the pressure of the steam supplied to the outside. According to the present configuration, the heat generation amount of the heat generation body is easily controlled such that the steam pressure is adjusted to a proper value. More specifically, as the above-described configuration, it may be configured such that the boiler heats a heat medium as the fluid to supply the heat medium to the outside and the controller controls the heat generation amount based on the temperature of the heated heat medium.
More specifically, as the above-described configuration, it may be configured such that the boiler further includes a heat transfer pipe configured such that the fluid flows inside and the heat transfer pipe is arranged to surround the heat generation body. According to the present configuration, heat generated by the heat generation body can be extremely efficiently transmitted to water targeted for heating.
More specifically, as the above-described configuration, it may be configured such that the heat transfer pipe spirally extends and is arranged to surround the heat generation body. More specifically, as the above-described configuration, it may be configured such that the heat transfer pipe includes multiple water pipes extending in the vertical direction and the water pipes are arranged to surround the heat generation body. More specifically, as the above-described configuration, it may be configured such that the heat transfer pipe is heated by conduction, convection, and radiation of heat generated by the heat generation body.
More specifically, as the above-described configuration, it may be configured such that the boiler further includes a heat exchanger provided outside the container and configured such that fluid as the gas heated by the heat generation body or a heat medium heat-exchanged with the gas passes through a heating side and a bypass path provided in parallel with the heat exchanger and bypassing the heating side of the heat exchanger. More specifically, as the above-described configuration, it may be configured such that the controller adjusts the flow rate of the fluid flowing in the bypass path based on the pressure of steam supplied from the heat exchanger to the outside. More specifically, as the above-described configuration, it may be configured such that the controller adjusts the flow rate and the heat generation amount of the heat generation body based on the pressure of the steam supplied from the heat exchanger to the outside.
More specifically, as the above-described configuration, it may be configured such that the boiler further includes a gas pump provided in the circulation path and a gas receiving portion provided on a primary side of the gas pump and configured to receive the gas from the outside. More specifically, as the above-described configuration, it may be configured such that the circulation path connects an upper portion and a lower portion of the container. More specifically, as the above-described configuration, it may be configured such that the heat transfer pipe is placed between a side wall of the container and the heat generation body. More specifically, as the above-described configuration, it may be configured such that the boiler includes a water pipe to be heated by heat generated by the heat generation body and heats water as the fluid when the water passes through the water pipe and the water pipe is arranged to surround the heat generation body.
The above-described object and features and other objects and features of the present invention are more clarified with reference to the following description of preferred embodiments and the attached drawings illustrating as follows.
Hereinafter, a boiler according to each embodiment of the present invention will be described with reference to each drawing.
First, a first embodiment of the present invention will be described.
Note that the states of the container 11 and the inside thereof in
The container 11 is, as a whole, formed in a cylindrical shape having bottoms at both upper and lower ends in the upper-lower direction as an axial direction, and is formed so that gas can be sealed inside. More specifically, the container 11 has a cylindrical side wall 11a formed by the later-described heat transfer pipe 22a, and the upper side of the side wall 11a is closed by an upper bottom portion 11b and the lower side of the side wall 11a is closed by a lower bottom portion 11c. Note that in the present embodiment, the side wall 11a of the container 11 is in the cylindrical shape as one example, but may be formed in other tubular shapes. Alternatively, a can body cover may be placed at the outer periphery of the side wall 11a, and a heat insulating member may be provided between the side wall 11a and the can body cover. Alternatively, the side wall 11a itself may have a can body cover function, and placement of the can body cover may be omitted.
The reactant 12 is configured such that many metal nanoparticles are provided on a surface of a carrier formed in a fine mesh shape as a whole. Hydrogen storing alloys (hydrogen storing metal or hydrogen storing alloy) are applied as the material of this carrier, and the carrier is formed in a cylindrical shape having bottoms at both upper and lower ends in the upper-lower direction as the axial direction. An upper surface of the reactant 12 is connected to the gas path 14 so that gas having flowed into the reactant 12 through mesh-shaped clearances thereof can be delivered into the gas path 14. In the example of the present embodiment, three reactants 12 are provided next to each other in a right-left direction in the container 11.
The heater 13 is spirally wound around a side surface of the reactant 12 formed in the bottomed cylindrical shape, and is formed to generate heat by using supplied power. For example, a ceramic heater may be employed as the heater 13. The heater 13 generates heat to heat the reactant 12 so that the temperature of the reactant 12 can be increased to a predetermined reaction temperature at which reaction for generating later-described excess heat is easily made. Note that the controller 26 controls a power supply to the heater 13 so that the temperature of the heater 13 can be adjusted.
The control of the power supply to the heater 13 by the controller 26 may be performed such that the temperature of the heater 13 approaches a target value. For example, the controller 26 may increase the power supply to the heater 13 in a case where the controller 26 detects the temperature of the heater 13 and such a detection value is lower than the target value, and may decrease the power supply to the heater 13 in a case where the detection value is higher than the target value.
The gas path 14 is provided outside the container 11, and forms a gas circulation path CR including, as part thereof, the inside of the container 11. One end portion of the gas path 14 is connected to the upper surface of each reactant 12, and the other end portion is connected to the inside of the container 11. More specifically, portions of the gas path 14 connected to the upper surfaces of the reactants 12 are joined together in the container 11, and after having penetrated the upper bottom portion 11b as a single path, further penetrate the lower bottom portion 11c through the gas receiving portion 15, the gas pump 16, and the gas filter 17 and are connected to the inside of the container 11.
The gas receiving portion 15 receives a supply of hydrogen-based gas (heavy hydrogen gas, light hydrogen gas, or a combination thereof) from an external supply source, and causes the supplied hydrogen-based gas to flow into the gas path 14. For example, in a case where the hydrogen-based gas is supplied from a tank storing the hydrogen-based gas in advance to the gas receiving portion 15, such a tank is a hydrogen-based gas supply source.
For example, the rotational speed of the gas pump 16 is controlled by inverter control, and with a flow rate according to this rotational speed, gas in the gas path 14 flows from an upstream side to a downstream side (i.e., to a direction indicated by dashed arrows in
This rotational speed control by the controller 26 may be performed such that the gas circulation amount in the gas circulation path CR approaches a target value. For example, the controller 26 may increase the rotational speed of the gas pump 16 to increase the circulation amount in a case where the controller 26 detects the circulation amount and such a detection value is lower than the target value, and may decrease the rotational speed of the gas pump 16 to decrease the circulation amount in a case where the detection value is higher than the target value.
The gas filter 17 removes an impurity (specifically, one as a cause for interference with the reaction for generating the excess heat in the reactant 12) contained in gas in the gas path 14. The separator 21 receives steam generated by heating of water (one example of fluid) through the heat transfer pipe 22a, and performs steam separation (separation of drain contained in such steam) for the steam. The steam separated in the separator 21 can be supplied to the outside of the boiler 1.
The fluid path 22 is a water path connected from the water receiving portion 23 to the separator 21. Part of the fluid path 22 is the heat transfer pipe 22a forming the side wall 11a as described above. Moreover, in the middle of the fluid path 22, the water pump 24 is arranged at a position immediately on the downstream side of the water receiving portion 23. Note that liquid water supplied from the water receiving portion 23 flows in the upstream-side path of the fluid path 22 with respect to the heat transfer pipe 22a, and water (steam) evaporated by heating in the heat transfer pipe 22a flows in the downstream-side path (between the container 11 and the separator 21) with respect to the heat transfer pipe 22a.
The water receiving portion 23 receives, as necessary, a supply of water as a steam source from the outside, and causes the supplied water to flow into the fluid path 22. The water pump 24 causes water in the fluid path 22 to flow from the upstream side to the downstream side (i.e., to a direction indicated by solid arrows in
The heat transfer pipe 22a spirally extends from the lower bottom portion 11c to the upper bottom portion 11b to form the tubular side wall 11a of the container 11. That is, the heat transfer pipe 22a spirally extends in the axial direction (the upper-lower direction) of the tubular side wall 11a such that no clearance is formed between adjacent portions of the heat transfer pipe 22a in the upper-lower direction. Note that in the example of the present embodiment, the sectional shape of an inner wall of the heat transfer pipe 22a is in a rectangular shape, but may be a circular shape or other shapes.
The pressure sensor 25 continuously detects the pressure (hereinafter referred to as a “steam pressure”) of steam supplied from the separator 21 to the outside. Note that a detection value (the value of the steam pressure) of the pressure sensor 25 is high under a situation where the amount of steam supplied from the boiler 1 is greater than a steam amount (a steam load) required from the outside, and conversely, is low under a situation where the amount of steam supplied from the boiler 1 is smaller. Information on the detection value of the pressure sensor 25 is continuously transmitted to the controller 26.
The controller 26 includes a computing device and the like, and controls a heat generation amount of the reactant 12 based on the detection value of the pressure sensor 25. Specific operation contents of the controller 26 will be described in detail again.
Next, operation of the boiler 1 will be described. In the boiler 1, the hydrogen-based gas is supplied from the external supply source to the gas receiving portion 15, and the gas circulation path CR including the inside of the container 11 and the gas path 14 is filled with the hydrogen-based gas. Due to action of the gas pump 16, the charged hydrogen-based gas circulates to the direction indicated by the dashed arrows in
At this point, in the container 11, the hydrogen-based gas is delivered into the gas path 14 connected to upper portions of the reactants 12 after having flowed in the reactants 12 through the mesh-shaped clearances thereof. At the same time, the reactants 12 are heated by action of the heaters 13. When the reactants 12 are, as described above, heated by the heaters 13 in a state in which the hydrogen-based gas has been supplied into the container 11, hydrogen atoms are stored in the metal nanoparticles provided on the reactants 12, and the reactants 12 generate an excess heat of equal to or higher than the temperature of heating by the heater 13. As described above, since the reactant 12 makes the reaction for generating the excess heat, the reactant 12 functions as a heat generation body. The principle of the reaction for generating the excess heat is, for example, similar to the principle of reaction for generating excess heat as disclosed in Patent Literature 1.
From the hydrogen-based gas in the gas circulation path CR including the inside of the container 11, the impurity is removed when the hydrogen-based gas passes through the gas filter 17. Thus, the high-purity hydrogen-based gas from which the impurity has been removed is continuously supplied into the container 11. With this configuration, the high-purity hydrogen-based gas can be stably provided to the reactants 12, a state in which the output of the excess heat is easily induced can be maintained, and the reactants 12 can effectively generate heat.
In parallel with the operation of generating heat from the reactants 12 as described above, water is supplied from the outside to the water receiving portion 23. The supplied water flows, due to action of the water pump 24, to the direction indicated by the solid arrows in
When passing through the heat transfer pipe 22a forming the side wall 11a of the container 11, the water flowing in the fluid path 22 is heated by heat generated by the reactants 12. That is, the heat generated by the reactants 12 is transmitted to the heat transfer pipe 22a by convection (heat transfer), heat conduction, and radiation by the hydrogen-based gas in the container 11, and the heat transfer pipe 22a of which temperature has been increased by such transmission heats the water flowing in the heat transfer pipe 22a.
In this manner, the water flowing in the fluid path 22 is heated when passing through the heat transfer pipe 22a, and the temperature thereof increases. Eventually, the water turns into steam. Such steam is delivered to the separator 21, and after the dryness of the steam has been increased by steam separation, is supplied to the outside of the boiler 1.
The amount of steam supplied from the separator 21 to the outside can be, for example, adjusted according to the amount of steam required from the outside. Moreover, in the boiler 1, water is sequentially supplied to the water receiving portion 23 by an amount corresponding to a steam supply to the outside, i.e., a water decrement, and steam can be continuously generated and supplied to the outside.
The amount of heat generation by the reactant 12 as described herein varies according to the temperature of the heater 13 and the hydrogen-based gas circulation amount. That is, as the temperature of the heaters 13 increases, the reaction for generating the excess heat in the reactant 12 is more accelerated, and the heat generation amount of the reactant 12 increases. Moreover, as the hydrogen-based gas circulation amount increases, more hydrogen-based gas in the container 11 acts on the reactant 12, the reaction for generating the excess heat is more accelerated, and the heat generation amount of the reactant 12 increases. Further, as the heat generation amount of the reactant 12 increases, heating of water in the heat transfer pipe 22a is more accelerated to generate more steam, and the steam pressure increases.
Utilizing this situation, the controller 26 controls the heat generation amount of the reactant 12 such that a proper steam pressure is brought (the detection value of the pressure sensor 25 falls within a preset proper range). A specific example of operation of the controller 26 will be described below with reference to a flowchart illustrated in
The controller 26 acquires the latest information on the detection value of the pressure sensor 25, and continuously monitors whether or not such a detection value falls within the proper range (steps S1 to S3). This proper range is preferably properly set in advance according to, e.g., the specifications of the boiler 1 and the steam load.
In a case where the detection value exceeds the proper range (Yes at the step S2), the controller 26 adjusts the temperature of the heater 13 to decrease by a predetermined value A1 (a step S11), adjusts the hydrogen-based gas circulation amount to decrease by a predetermined value A2 (a step S12), and returns to operation at the step S1.
Note that each of the above-described values A1, A2 is preferably set so that the heat generation amount of the reactant 12 can be moderately changed. By execution of adjustment at the steps S11 to S12, the heat generation amount of the reactant 12 decreases, and the steam pressure decreases and approaches the proper range.
On the other hand, in a case where the detection value falls below the proper range (Yes at the step S3), the controller 26 adjusts the temperature of the heater 13 to increase by a predetermined value B1 (a step S21), adjusts the hydrogen-based gas circulation amount to increase by a predetermined value B2 (a step S22), and returns to operation at the step S1.
Note that each of the above-described values B1, B2 is preferably set so that the heat generation amount of the reactant 12 can be moderately changed. By execution of adjustment at the steps S21 to S22, the heat generation amount of the reactant 12 increases, and the steam pressure increases and approaches the proper range. By execution of a series of operation illustrated in
Adjustment (adjustment of the temperature of the heater 13) at the steps S11, S21 can be implemented in such a manner that a power supply to the heater 13 is changed as necessary. Moreover, adjustment (adjustment of the hydrogen-based gas circulation amount) at the steps S12, S22 can be implemented in such a manner that the rotational speed of the gas pump 16 is changed as necessary.
Moreover, in a series of operation illustrated in
Further, an acceptable range may be provided for the value of each of the above-described items, and operation of the controller 26 may be executed without deviating from this acceptable range. For example, under a situation where the temperature of the heater 13 has already reached the upper limit of the acceptable range, even in a case where the detection value of the pressure sensor 25 falls below the proper range (Yes at the step S3), adjustment (the step S21) for increasing the temperature of the heaters 13 may be omitted, and only adjustment (the step S22) for increasing the hydrogen-based gas circulation amount may be performed. With this configuration, an adverse effect (e.g., failure of the heater 13) due to an excessive increase in the temperature of the heater 13 can be prevented in advance.
Next, a second embodiment of the present invention will be described. Note that the second embodiment is basically similar to the first embodiment, except for the form of a heat generation body and points relating thereto. In description below, description of contents different from those of the first embodiment will be focused, and description of contents common to the first embodiment might be omitted.
In the boiler 2, a heat transfer pipe 22a is heated by heat generated from the heat generation elements 12a instead of the reactants 12, and the heat from the heat transfer pipe 22a (a side wall 11a of a container 11) is transmitted to water passing through the heat transfer pipe 22a, and the temperature of the water increases. Moreover, in this form, the above-described reaction for generating the excess heat is not necessary, and the temperature of the heat generation element 12a is directly controlled by power control so that water can be moderately heated to generate steam.
Moreover, in the boiler 2, a controller 26 adjusts the power supply to the heat generation element 12a so that a heat generation amount of the heat generation element 12a (the heat generation body) can be controlled. A specific example of operation of the controller 26 in the second embodiment will be described below with reference to a flowchart illustrated in
The controller 26 acquires the latest information on a detection value of a pressure sensor 25, and continuously monitors whether or not such a detection value falls within a proper range (steps S1 to S3). This proper range is preferably properly set in advance according to, e.g., the specifications of the boiler 2 and a steam load.
In a case where the detection value exceeds the proper range (Yes at the step S2), the controller 26 adjusts the temperature of the heat generation element 12a to decrease by a predetermined value A4 (a step S14), and returns to operation at the step S1. Note that the above-described value A4 is preferably set so that the heat generation amount of the heat generation element 12a can be moderately changed. By execution of adjustment at the step S14, the heat generation amount of the heat generation element 12a decreases, and a steam pressure decreases and approaches the proper range.
On the other hand, in a case where the detection value falls below the proper range (Yes at the step S3), the controller 26 adjusts the temperature of the heat generation element 12a to increase by a predetermined value B4 (a step S24), and returns to operation at the step S1. Note that the above-described value B4 is preferably set so that the heat generation amount of the heat generation element 12a can be moderately changed. By execution of adjustment at the step S24, the heat generation amount of the heat generation element 12a increases, and the steam pressure increases and approaches the proper range. By execution of a series of operation illustrated in
The boiler 1, 2 of each embodiment described above includes the heat generation bodies and the container 11 having the heat generation bodies inside, and is configured to heat supplied water to generate steam. Further, each boiler 1, 2 includes the heat transfer pipe 22a to be heated by heat generated by the heat generation bodies under environment where the inside of the container 11 is filled with gas (the hydrogen-based gas in the examples of the present embodiments) with higher specific heat than that of air, and water (water as the steam source) passing through the heat transfer pipe 22a is heated. Note that under, e.g., a condition of 1 atm at 200° C., the specific heat of air is about 1,026 J/Kg° C., and on the other hand, the specific heat of hydrogen is about 14,528 J/Kg° C. and is extremely higher than the specific heat of air. Moreover, as the heat generation body, the reactant 12 is employed in the boiler 1, and the heat generation element 12a is employed in the boiler 2.
According to each boiler 1, 2, heat generated by the heat generation bodies can be efficiently transmitted to water while such water is heated by a heat generation unit including the heat generation bodies in the container 11 to generate steam. As a result, the heat generated by the heat generation bodies can be efficiently transmitted to the water as the steam source.
Further, the inside of the container 11 is filled with gas with higher specific heat than that of air, and therefore, heat transfer can be favorably performed as compared to the case of charging general air, and heat generated by the heat generation bodies can be efficiently transmitted to water as the steam source. Moreover, due to high specific heat, it is less likely to fluctuate the temperature of gas, and heat can be more stably transmitted to water.
Moreover, the heat transfer pipe 22a forms the entire periphery of the side wall 11a formed in the tubular shape, and therefore, heat generated by the heat generation bodies can be efficiently transmitted to water as the steam source. Specifically, the heat transfer pipe 22a in the present embodiments is arranged to surround the heat generation bodies, and therefore, the substantially entire area of the periphery of the side wall 11a can be covered and heat generated by the heat generation bodies can be transmitted to water as the steam source with as least waste as possible. Note that in each of the above-described embodiments, the heat transfer pipe spirally extends and is arranged to surround the heat generation bodies, but the form surrounding the heat generation bodies is not limited to above. For example, a form in which multiple heat transfer pipes extending in the vertical direction are arranged to surround the heat generation bodies may be employed.
Moreover, in each of the above-described embodiments, the side wall 11a for sealing gas in the container 11 is formed by the heat transfer pipe 22a. Instead, the side wall 11a may be provided separately from the heat transfer pipe 22a, and the heat transfer pipe 22a may be provided inside the side wall 11a (i.e., in the container 11). In this case, under environment where the inside of the container 11 is filled with gas with higher specific heat than that of air, the heat transfer pipe 22a can be also heated by heat generated by the heat generation bodies. Moreover, in this case, the heat transfer pipe 22a does not necessarily fulfill a function as the side wall 11a, but preferably fulfills such a function because the heat transfer pipe 22a more easily receives heat from the heat generation bodies when there is a clearance between adjacent portions of the heat transfer pipe 22a in the upper-lower direction.
In each boiler 1, 2, the above-described gas circulates in the gas circulation path CR including, as part thereof, the inside of the container 11. With this configuration, the effect of accelerating gas motion in the container 11 and more effectively performing heat transfer from the gas to the side wall 11a is expected. Note that in the boiler 2 of the second embodiment not requiring the reaction for generating the excess heat, a mechanism configured to circulate gas in the container 11 may be omitted, and instead, a mechanism configured to supply gas into the container 11 to fill the container 11 with the gas may be provided. Moreover, the reaction for generating the excess heat is not necessary in the boiler 2, and therefore, gas other than the hydrogen-based gas may be employed as the above-described gas with higher specific heat than that of air.
Moreover, each boiler 1, 2 includes the controller 26 configured to control the heat generation amount of the heat generation body, and therefore, water can be moderately heated according to various situations. Specifically, in each of the above-described embodiments, the heat generation amount is controlled based on the steam pressure (the pressure of steam supplied to the outside), and therefore, is easily controlled such that the steam pressure is adjusted to a proper value. Note that the control of the heat generation amount of the heat generation body according to the present invention is not limited to the control based on the steam pressure, but may be control based on various other types of information.
Note that in each of the above-described embodiments, water as the steam source flows in the fluid path 22 including the heat transfer pipe 22a. Instead, a heat medium (fluid for a heat medium) may flow in the fluid path 22 so that water as the steam source can be heated using this heat medium.
Next, a third embodiment of the present invention will be described. Note that in description below, description of contents different from those of the first embodiment will be focused, and description of contents common to the first embodiment might be omitted.
The heat medium path 40 includes a heat medium outlet 25a arranged on a downstream side with respect to the heat transfer pipe 40a and a heat medium inlet 25b arranged on an upstream side with respect to the heat transfer pipe 40a, and the load Z can be connected to between the heat medium outlet 25a and the heat medium inlet 25b. Note that as the load Z, various devise utilizing heat of the heat medium Y can be employed, for example. After having passed through the load Z, the heat medium Y having flowed out of the heat medium outlet 25a flows into the heat medium inlet 25b. With this configuration, the heat medium Y can circulate, in the boiler 3 connected to the load Z, in a circulation path including the heat medium path 40 and the load Z as indicated by solid arrows in
Moreover, in the boiler 3, a controller 26 can control a heat generation amount of the reactant 12 based on a detection value of the temperature of the heat medium Y obtained by, e.g., a temperature sensor. In the example of the present embodiment, the temperature (the outlet temperature of the heat medium Y) of the heat medium Y at the heat medium outlet 25a is detected, and based on such a temperature, the controller 26 controls the heat generation amount of the reactant 12.
More specifically, the controller 26 acquires, instead of operation (see
Note that the specific form for controlling the heat generation amount of the reactant 12 based on the temperature of the heat medium Y is not limited to one described above. As one example, the temperature (a return port temperature of the heat medium Y) of the heat medium Y at the heat medium inlet 25b may be detected, and based on such a temperature, the controller 26 may control the heat generation amount of the reactant 12. As another example, the controller 26 may control the heat generation amount of the reactant 12 based on a difference between the temperature of the heat medium Y at the heat medium outlet 25a and the temperature of the heat medium Y at the heat medium inlet 25b.
Next, a fourth embodiment of the present invention will be described. Note that the fourth embodiment is basically similar to the first embodiment, except for the form of a heat generation body and points relating thereto. In description below, description of contents different from those of the first embodiment will be focused, and description of contents common to the first embodiment might be omitted.
The container 11 is, as a whole, formed in a cylindrical shape having bottoms at both upper and lower ends in an upper-lower direction as an axial direction, and is formed so that gas can be sealed inside. More specifically, the container 11 has a cylindrical side wall 11a, and the upper side of the side wall 11a is closed by an upper bottom portion 11b and the lower side of the side wall 11a is closed by a lower bottom portion 11c. Note that in the present embodiment, the side wall 11a of the container 11 is in the cylindrical shape as one example, but may be formed in other tubular shapes. Alternatively, a can body cover may be placed at the outer periphery of the side wall 11a, and a heat insulating member may be provided between the side wall 11a and the can body cover.
The gas path 14 is provided outside the container 11, and forms a gas circulation path CR including, as part thereof, the inside of the container 11. One end portion of the gas path 14 is connected to an upper surface of each reactant 12, and the other end portion is connected to the inside of the container 11. More specifically, portions of the gas path 14 connected to the upper surfaces of the reactants 12 are joined together in the container 11, and after having penetrated the upper bottom portion 11b as a single path, further penetrate the lower bottom portion 11c through the heat exchanger 50, the gas receiving portion 15, the gas pump 16, and the gas filter 17 in this order and are connected to the inside of the container 11.
The heat exchanger 50 is configured such that part (an upstream-side portion with respect to the gas receiving portion 15) of the gas path 14 is arranged in the heat exchanger 50 and water as a steam source is supplied to the heat exchanger 50. With this configuration, the heat exchanger 50 performs heat exchange between gas in the gas path 14 and supplied water so that the water can be heated to generate steam and the steam can be supplied to the outside of the boiler 4. Note that the heat exchanger 50 of the present embodiment has specifications for heating water to generate steam. Instead, one with specifications for heating water to generate hot water may be employed.
For example, a plate or shell-and-tube heat exchanger may be employed as the heat exchanger 50, or various forms of steam generators may be employed. As one example of these steam generators, there is one having a storage space for storing supplied water and a gas path 14 arranged in the storage space and configured to transmit heat of gas in the gas path 14 to the stored water.
The pressure sensor 25 continuously detects the pressure (a steam pressure) of steam supplied from the heat exchanger 50 to the outside. Note that a detection value (the value of the steam pressure) of the pressure sensor 25 is great under a situation where the amount of steam supplied from the heat exchanger 50 is greater than a steam amount (a steam load) required from the outside, and conversely, is small under a situation where the amount of steam supplied from the heat exchanger 50 is smaller.
Moreover, in the gas path 14 of the boiler 4 as illustrated in
Further, in the gas path 14, an adjustment valve 18 is placed at a branched point between a path toward the heat exchanger 50 and the bypass path 14a. The adjustment valve 18 can adjust the flow rate of gas (hydrogen-based gas) flowing in the bypass path 14a. As the flow rate of gas flowing in the bypass path 14a increases, the flow rate of gas flowing in the heat exchanger 50 decreases accordingly.
Next, operation of the boiler 4 will be described. In the boiler 4, the hydrogen-based gas is supplied from an external supply source to the gas receiving portion 15, and the gas circulation path CR including the inside of the container 11 and the gas path 14 is filled with the hydrogen-based gas. Due to action of the gas pump 16, the charged hydrogen-based gas circulates to a direction indicated by dashed arrows in
At this point, in the container 11, the hydrogen-based gas is delivered into the gas path 14 connected to upper portions of the reactants 12 after having flowed in the reactants 12 through mesh-shaped clearances thereof. At the same time, the reactants 12 are heated by action of the heaters 13. When the reactants 12 are, as described above, heated by the heaters 13 in a state in which the hydrogen-based gas has been supplied into the container 11, hydrogen atoms are stored in metal nanoparticles provided on the reactants 12, and the reactants 12 generate an excess heat of equal to or higher than the temperature of heating by the heater 13.
When passing through the container 11, the hydrogen-based gas is heated to a high temperature by heat generated by the reactants 12. Then, the high-temperature hydrogen-based gas is delivered to the heat exchanger 50 through the gas path 14. Accordingly, water supplied to the heat exchanger 50 is heated by heat exchange with the high-temperature hydrogen-based gas, and turns into steam. Such steam is supplied from the heat exchanger 50 to the outside.
The amount of steam supplied from the heat exchanger 50 to the outside is, by the controller 26, adjusted based information on the detection value of the pressure sensor 25. Such adjustment can be implemented in such a manner that a heat generation amount of the reactant 12 is increased such that a steam generation amount increases when the detection value of the pressure sensor 25 is smaller than a proper value and is decreased such that the steam generation amount decreases when the detection value of the pressure sensor 25 is greater than the proper value.
Note that the heat generation amount of the reactant 12 can be controlled by adjustment of the temperature of the heater 13 or the above-described gas circulation amount by the controller 26. As the temperature of the heater 13 increases or the circulation amount increases, the heat generation amount of the reactant 12 can be increased. Moreover, in the heat exchanger 50, water is sequentially supplied by an amount corresponding to a steam supply to the outside, i.e., a water decrement, and therefore, steam can be continuously generated and supplied to the outside.
As described above, the boiler 4 includes the reactants 12, the container 11 having the reactants 12 inside and configured so that the inside of the container 11 can be filled with gas (the hydrogen-based gas) with higher specific heat than that of air, the gas circulation path CR including the container 11 and the gas path 14 as a path for circulating the hydrogen-based gas, and the heat exchanger 50 configured to heat water by heat exchange with the hydrogen-based gas in the gas path 14 to generate steam. Thus, according to the boiler 4, heat held by circulating gas can be efficiently utilized for heating water, and such heat can be more effectively utilized.
Further, the temperature of gas in the gas path 14 decreases by way of the heat exchanger 50, and accordingly, the temperature of gas when the gas passes through a device (in the example of the present embodiment, the gas pump 16 or the gas filter 17) arranged on the downstream side with respect to the heat exchanger 50 can be decreased. Thus, a heatproof temperature (a required heatproof temperature) required for such a device can be also decreased.
In addition, by flow rate adjustment by the adjustment valve 18, as the flow rate of gas flowing in the heat exchanger 50 decreases, heating of water in the heat exchanger 50 can be weakened, and the steam generation amount can be decreased. Conversely, as the flow rate of gas flowing in the heat exchanger 50 increases, heating of water in the heat exchanger 50 can be strengthened, and the steam generation amount can be increased. Note that gas flowing in the bypass path 14a is returned to the gas path 14 at a position immediately on the downstream side of the heat exchanger 50. Thus, the flow rate of gas in the gas path 14 on the downstream side with respect to such a position does not depend on the flow rate of gas flowing in the bypass path 14a.
In the present embodiment, the bypass path 14a and the adjustment valve 18 are provided so that the amount of steam supplied from the heat exchanger 50 to the outside can be adjusted by the control of the adjustment valve 18 by the controller 26. Such adjustment can be implemented in such a manner that the adjustment valve 18 is controlled such that the flow rate of gas flowing in the heat exchanger 50 increases when the detection value of the pressure sensor 25 is smaller than the proper value and is controlled such that the flow rate of gas flowing in the heat exchanger 50 decreases when the detection value of the pressure sensor 25 is greater than the proper value.
Note that the controller 26 may adjust both of the flow rate of gas flowing in the bypass path 14a and the heat generation amount of the reactant 12 based on the detection value (the pressure of steam supplied from the heat exchanger 50 to the outside) of the pressure sensor 25. With this configuration, both of the flow rate and the heat generation amount can be changed with favorable balance, and the amount of steam supplied from the heat exchanger 50 to the outside can be adjusted.
Alternatively, which one of the flow rate or the heat generation amount is to be adjusted may be set as necessary. For adjustment of the heat generation amount of the reactant 12, the controller 26 adjusts both items of the temperature of the heater 13 and the hydrogen-based gas circulation amount according to the detection value of the pressure sensor 25. Note that according to various situations, only either one of the items may be adjusted instead of adjusting both items described above. As necessary, which one of these items is to be adjusted can be set.
Next, a fifth embodiment of the present invention will be described. Note that the fifth embodiment is basically similar to the fourth embodiment, except for the form of a heat generation body and points relating thereto. In description below, description of contents different from those of the fourth embodiment will be focused, and description of contents common to the fourth embodiment might be omitted.
In a case where the heat generation element 12a is applied as a heat generation body, excess heat is not necessarily generated as in the fourth embodiment, and one equivalent to a heater 13 is not necessary and placement thereof is omitted. Moreover, an upstream-side end portion of a gas path 14 in the fifth embodiment is connected to an upper bottom portion 11b instead of the heat generation element 12a, and is connected to a space in a container 11.
In the boiler 5, gas (hydrogen-based gas) in the container 11 is heated by heat generated from the heat generation elements 12a instead of the reactants 12, and such high-temperature gas is delivered to a heat exchanger 50 through the gas path 14. Accordingly, water supplied to the heat exchanger 50 is heated by heat exchange with the high-temperature gas, and turns into steam. Such steam is supplied from the heat exchanger 50 to the outside. Moreover, in the fifth embodiment, the above-described reaction for generating the excess heat is not necessary, and a controller 26 can directly control the temperature of the heat generation body (the heat generation element 12a) by power control.
Next, a sixth embodiment of the present invention will be described. Note that in description below, description of contents different from those of the fourth embodiment will be focused, and description of contents common to the fourth embodiment might be omitted.
Part of the fluid path 22 is formed as a heat transfer pipe 22a. The heat transfer pipe 22a spirally extends from a lower bottom portion 11c to an upper bottom portion 11b to form a tubular side wall 11a of a container 11. The heat transfer pipe 22a spirally extends in an axial direction (an upper-lower direction) of the tubular side wall 11a such that no clearance is formed between adjacent portions of the heat transfer pipe 22a in the upper-lower direction.
Moreover, a heat exchanger 50 of the sixth embodiment is configured such that part of the fluid path 22 is arranged in the heat exchanger 50 and water as a steam source is supplied to the heat exchanger 50. With this configuration, the heat exchanger 50 performs heat exchange between the heat medium X in the fluid path 22 and supplied water so that the water can be heated to generate steam and the steam can be supplied to the outside of the boiler 6.
Further, in the sixth embodiment, a bypass path 22b is provided in the fluid path 22 instead of providing a bypass path 14a in a gas path 14. More specifically, in the fluid path 22, the bypass path 22b is provided to connect a position immediately on the upstream side of the heat exchanger 50 and a position immediately on the downstream side of the heat exchanger 50. As described above, the bypass path 22b is provided in parallel with the heat exchanger 50, and fulfills a role as a bypass extending around the heat exchanger 50.
Note that an adjustment valve 18 in the sixth embodiment is placed at a branched point between a path toward the heat exchanger 50 and the bypass path 22b in the fluid path 22, and can adjust the flow rate of the heat medium X flowing in the bypass path 22b. As the flow rate of the heat medium X flowing in the bypass path 22b increases, the flow rate of the heat medium X flowing in the heat exchanger 50 decreases accordingly.
The boiler 6 of the present embodiment circulates the heat medium X in the fluid path 22 in parallel with the operation of generating heat from reactants 12. When passing through the heat transfer pipe 22a forming the side wall 11a of the container 11, the heat medium X is heated by heat generated by the reactants 12. That is, heat generated by the reactants 12 is transmitted to the heat transfer pipe 22a by convection (heat transfer), heat conduction, and radiation by hydrogen-based gas in the container 11, and the heat transfer pipe 22a of which temperature has been increased by such transmission heats the heat medium X flowing in the heat transfer pipe 22a. As described above, the heat medium X is heated at least by heat exchange with the hydrogen-based gas heated by the reactants 12. Note that the heat transfer pipe 22a of the present embodiment has a configuration equivalent to that of the heat transfer pipe 22a of the first embodiment. The heat medium X having reached an inlet (the lowermost portion of the heat transfer pipe 22a) of the heat transfer pipe 22a flows along the inside of the spirally-extending heat transfer pipe 22a, and reaches an outlet (the uppermost portion of the heat transfer pipe 22a) of the heat transfer pipe 22a. At this point, heat from the heat transfer pipe 22a heated by heat generated by the reactants 12 is transmitted to the heat medium X passing through the heat transfer pipe 22a, and the temperature of the heat medium X increases.
In this manner, the heat medium X flowing in the fluid path 22 is heated when passing through the heat transfer pipe 22a such that the temperature thereof increases, and is delivered to the heat exchanger 50. Accordingly, water supplied to the heat exchanger 50 is heated by heat exchange with the high-temperature heat medium X, and turns into steam. Such steam is supplied from the heat exchanger 50 to the outside. Note that, e.g., the control of the adjustment valve 18 is performed in a manner equivalent to that in the case of the fourth embodiment by the controller 26.
Moreover, the heat transfer pipe 22a forms the entire periphery of the side wall 11a formed in the tubular shape, and therefore, heat generated by the reactants 12 can be efficiently transmitted to the heat medium X. The heat transfer pipe 22a is arranged to surround the reactants 12, and therefore, the substantially entire area of the periphery of the side wall 11a can be covered and heat generated by the reactants 12 can be transmitted to the heat medium X with as least waste as possible. Note that in the present embodiment, the heat transfer pipe 22a spirally extends and is arranged to surround the reactants 12, but the form surrounding the reactants 12 is not limited to above. For example, a form in which multiple heat transfer pipes extending in the vertical direction are arranged to surround the reactants 12 may be employed.
Further, in the present embodiment, the side wall 11a for sealing gas in the container 11 is formed by the heat transfer pipe 22a. Instead, the side wall 11a may be provided separately from the heat transfer pipe 22a, and the heat transfer pipe 22a may be provided inside the side wall 11a (i.e., in the container 11). In this case, the heat transfer pipe 22a does not necessarily fulfill a function as the side wall 11a, but preferably fulfills such a function because the heat transfer pipe 22a more easily receives heat from the reactants 12 when there is a clearance between adjacent portions of the heat transfer pipe 22a in the upper-lower direction.
Each of the boilers 4 to 6 of the fourth to sixth embodiments described above includes the heat generation bodies, the container 11 including the heat generation bodies inside and configured so that the inside of the container 11 can be filled with gas with higher specific heat than that of air, and the heat exchanger 50 configured to heat water by heat exchange with fluid heated by heat of the heat generation bodies. In the path for such fluid, the bypass path 14a (or 22b) is provided in parallel with the heat exchanger 50. Thus, each of the boilers 4 to 6 of the embodiments heats water by utilizing fluid directly or indirectly heated by the heat generation bodies in the container 11, and adjusts the flow rate of fluid flowing in the bypass path. Thus, heating of water can be easily adjusted.
Note that each of the boilers 4 to 6 includes the heat exchanger 50 provided outside the container 11 and configured such that fluid as the hydrogen-based gas heated by the heat generation bodies or the heat medium X heat-exchanged with the hydrogen-based gas passes through a heating side and the bypass path 14a provided in parallel with the heat exchanger 50 and bypassing the heating side of the heat exchanger 50. The heat exchanger 50 has the heating side (a portion through which relatively-high-temperature fluid passes) and a heated side (a portion through which relatively-low-temperature fluid passes), and is formed to perform heating by heat transfer from heating-side fluid to heated-side fluid.
Further, a radiator may be placed in the bypass path of each embodiment such that extra heat is released from fluid flowing in the bypass path. Note that a thermoelectric element may be placed in the bypass path in addition to or instead of the radiator, and electricity obtained by the thermoelectric element may be utilized as, e.g., stored power or drive power for the heater 13 (in the case of the fifth embodiment, the heat generation element 12a).
In addition, in each boiler of the fourth and fifth embodiments, the hydrogen-based gas with higher specific heat than that of air is applied as gas used for heat exchange with water in the heat exchanger 50. By application of such gas with higher specific heat, it is less likely to fluctuate the temperature of gas used for heat exchange, and heat can be more stably transmitted to water. Note that in each boiler of the fourth to sixth embodiments, the hydrogen-based gas is employed as gas with higher specific heat than that of air. However, the reaction for generating the excess heat is not necessary in the boiler 5 of the fifth embodiment, and therefore, gas other than the hydrogen-based gas may be employed as the above-described gas with higher specific heat than that of air.
Next, a seventh embodiment of the present invention will be described. Note that the seventh embodiment is basically similar to the first embodiment, except for points relating to the form of a heat transfer pipe. In description below, description of contents different from those of the first embodiment will be focused, and description of contents common to the first embodiment might be omitted.
The lower header 22b1 extends to form a circular shape on a lower side of a side wall 11a in a cylindrical shape, and at a lower left portion thereof, an inlet α of the lower header 22b1 is formed. The upper header 22b2 extends to form a circular shape on an upper side of the side wall 11a in the cylindrical shape, and at an upper left portion thereof, an outlet β of the upper header 22b2 is formed. The lower header 22b1 and the upper header 22b2 are set to the substantially same shape and dimensions, and are arranged to overlap with each other as viewed from above. A portion of the fluid path 22 extending from a water pump 24 is connected to the inlet α of the lower header 22b1, and a portion of the fluid path 22 extending from the outlet β of the upper header 22b2 is connected to a separator 21.
The multiple heat transfer pipes 22a extend in an upper-lower direction between the lower header 22b1 and the upper header 22b2, and are arranged next to each other in a circumferential direction of the cylindrical shape of the side wall 11a to form the side wall 11a in the cylindrical shape. Each of the multiple heat transfer pipes 22a is integrated such that there is no clearance between adjacent ones of the heat transfer pipes 22a in the circumferential direction.
An internal space of each of the multiple heat transfer pipes 22a is connected to an internal space of the lower header 22b1 on the lower side, and is connected to an internal space of the upper header 22b2 on the upper side. That is, the circular lower header 22b1 is connected to lower ends of all of the multiple heat transfer pipes 22a, and the circular upper header 22b2 is connected to upper ends of all of the multiple heat transfer pipes 22a. With this configuration, water having entered the lower header 22b1 through the inlet α can reach the outlet β through the heat transfer pipes 22a.
As described above, in the present embodiment, the fluid path 22 has the multiple heat transfer pipes 22a extending in an axial direction (the vertical direction) of the tubular side wall 11a. These heat transfer pipes 22a are arranged in the circumferential direction of the tubular shape to form the side wall 11a, and therefore, are arranged to surround heat generation bodies. Thus, in the present embodiment, the heat transfer pipes 22a are easily arranged to cover the substantially entire area of the periphery of the side wall 11a while the heat transfer pipes 22a are arranged to form a once-through boiler or one equivalent thereto. Heat generated by the heat generation bodies can be transmitted to water as a steam source with as least waste as possible. Note that the heat transfer pipes of the present embodiment are multiple water pipes (pipes through which water passes) extending in the vertical direction, and are arranged to surround the heat generation bodies. Moreover, the boiler of the present embodiment is a boiler including the water pipes heated by heat generated by the heat generation bodies and configured such that water is heated by passing through the water pipes, and the water pipes are arranged to surround the heat generation bodies.
Next, an eighth embodiment of the present invention will be described. Note that the eighth embodiment is basically similar to the first embodiment, except that a hydrogen-powered burner is employed as a reactant heating unit instead of a heater. In description below, description of contents different from those of the first embodiment will be focused, and description of contents common to the first embodiment might be omitted.
The hydrogen-powered burner 18s is a burner using hydrogen-based gas as fuel, and in a container 11, is arranged so that not only reactants 12 but also a side wall 11a can be heated. In the example of the present embodiment, the hydrogen-powered burner 18s is arranged to spurt combustion flame to among the reactants 12 and the side wall 11a to efficiently heat these components. Note that the hydrogen-powered burner 18s may be arranged outside the container 11, and may directly heat the side wall 11a and heat the reactants 12 through the side wall 11a.
In the present embodiment, the hydrogen-powered burner 18s fulfills a role in heating the reactants 12, and therefore, placement of the above-described heaters 13 can be omitted, and other external heat sources for increasing the temperature of the reactant 12 are not necessary either. Moreover, a supply source of the hydrogen-based gas supplied as the fuel of the hydrogen-powered burner 18s is common to that of hydrogen-based gas supplied to a gas receiving portion 15. With this configuration, the hydrogen-based gas supplied from such a supply source can be efficiently utilized, and it is also advantageous in, e.g., simplification of the configuration of the boiler.
Further, the hydrogen-powered burner 18s heats the side wall 11a so that water passing through the heat transfer pipes 22a can be heated. As described above, in the present embodiment, water can be heated not only by heat generated from the reactants 12, but also by the hydrogen-powered burner 18s. Thus, e.g., upon the start-up of the boiler 8, water is heated using the hydrogen-powered burner 18s until sufficient heat is generated from the reactants 12, and therefore, steam can be more promptly generated. Specifically, the reactant 12 has such properties that reaction starts after the temperature of the reactant 12 has increased to a predetermined reaction temperature and the reactant 12 gradually generates excess heat, and therefore, water is heated using the hydrogen-powered burner 18s upon the start-up so that time necessary until generation of steam can be significantly shortened.
Note that operation of a controller 26 of the present embodiment is basically similar to that of the first embodiment, except that the temperature of the hydrogen-powered burner 18s is adjusted instead of the heater. For adjustment of a heat generation amount of the reactant 12, the controller 26 adjusts both items of the temperature of the hydrogen-powered burner 18s and a hydrogen-based gas circulation amount according to a detection value of a pressure sensor 25. Note that according to various situations, only either one of the items may be adjusted instead of adjusting both items described above. As necessary, which one of these items is to be adjusted can be set.
The boiler of each embodiment described above is the boiler configured to heat fluid by using heat generated by the heat generation bodies, and includes the controller 26 configured to control the heat generation amount of the heat generation body under a situation where the hydrogen-based gas is supplied into the container 11. The boiler according to the present invention heats fluid by the heat generation unit including the heat generation bodies in the container, and can moderately heat fluid according to various situations where heat generated by the heat generation bodies can be efficiently utilized.
The embodiments of the present invention have been described above, but the configurations of the present invention are not limited to those of the above-described embodiments. Various changes can be made without departing from the gist of the invention. That is, the above-described embodiments are examples on all points, and should be considered as not being limited. For example, the boiler according to the present invention is also applicable to a hot water boiler, a heat medium boiler and the like in addition to the boiler generating steam as in the above-described embodiments. The technical scope of the present invention is not determined by description of the above-described embodiments, but is determined by the claims. It should be understood that meaning equivalent to that of the claims and all changes pertaining to the claims are included. Moreover, the present invention can be utilized for boilers for various purposes.
| Number | Date | Country | Kind |
|---|---|---|---|
| JP2019-207481 | Nov 2019 | JP | national |
| JP2020-045123 | Mar 2020 | JP | national |
| JP2020-126761 | Jul 2020 | JP | national |
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| Number | Date | Country | |
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| 20210123596 A1 | Apr 2021 | US |
