Electrode-type boiler

Abstract

A boiler 101 that is an electrode-type boiler comprises a water pipe 2 that is a boiler body in which water is accommodated, three electrodes 6 that are arranged inside the water pipe 2 and immersed in water, and a neutral pipe 7 that is arranged around each of the three electrodes 6. The three neutral pipes 7 are connected to each other. The three electrodes 6 form a star connection with the neutral pipes 7 as neutral points.

Description

Electrode boiler

[0001] The technology disclosed in this specification relates to an electrode boiler.

[0002] In the technical field of boilers, an electrode-type boiler such as that disclosed in Patent Document 1 is known. In an electrode-type boiler, a voltage is applied between a pair of electrodes immersed in water, causing a current to flow through the water. When a current flows through the water, Joule heat is generated due to the electrical resistance of the water. The Joule heat raises the temperature of the water, generating steam.

[0003] Chinese Patent Application Publication No. 107238068

[0004] Current flows along the route with the smallest resistance. Therefore, for example, when multiple electrodes form a delta connection, current flows along the shortest route between a pair of adjacent electrodes. In this case, current is output from or input to a portion of the outer surface of the electrode. Because only a portion of the outer surface of the electrode contributes to the generation of Joule heat, it becomes difficult to efficiently raise the temperature of the water.

[0005] This specification discloses an electrode boiler. The electrode boiler includes a boiler body that contains water, three electrodes that are disposed inside the boiler body and immersed in the water, and neutral tubes that are disposed around each of the three electrodes. The three neutral tubes are interconnected. The three electrodes form a star connection with the neutral tube as the neutral point.

[0006] According to the technology disclosed in this specification, the temperature of water can be increased efficiently.

[0007] FIG. 1 is a front view schematically showing a boiler according to a first embodiment. FIG. 2 is a cross-sectional view schematically showing a boiler according to the first embodiment. FIG. 3 is a cross-sectional view schematically showing a portion of the boiler according to the first embodiment. FIG. 4 is a block diagram showing the boiler according to the first embodiment. FIG. 5 is a perspective view schematically showing an electrode and a neutral tube according to the first embodiment. FIG. 6 is a cross-sectional view schematically showing a portion of a boiler according to a second embodiment. FIG. 7 is a perspective view schematically showing an electrode and a neutral tube according to the second embodiment. FIG. 8 is a perspective view schematically showing an electrode according to the second embodiment. FIG. 9 is a cross-sectional view schematically showing a portion of a boiler according to a third embodiment. FIG. 10 is a perspective view schematically showing an electrode and a neutral tube according to the third embodiment. FIG. 11 is a front view schematically showing a boiler according to a fourth embodiment. FIG. 12 is a cross-sectional view schematically showing a boiler according to the fourth embodiment.

[0008] Hereinafter, embodiments will be described with reference to the drawings. In the embodiments, a three-dimensional Cartesian coordinate system is defined, and the positional relationship of each part will be described with reference to the three-dimensional Cartesian coordinate system. The direction parallel to the X axis in a horizontal plane is defined as the X-axis direction. The direction parallel to the Y axis in a horizontal plane that is perpendicular to the X axis is defined as the Y-axis direction. The direction parallel to the Z axis that is perpendicular to the horizontal plane is defined as the Z-axis direction. The Z-axis direction is the up-down direction. The +Z side is the upper side, and the -Z side is the lower side.

[0009] [First embodiment] A first embodiment will be described. Fig. 1 is a front view schematically showing a boiler 101 according to this embodiment. Fig. 2 is a cross-sectional view schematically showing the boiler 101 according to this embodiment. Fig. 3 is a cross-sectional view schematically showing a portion of the boiler 101 according to this embodiment. Fig. 4 is a block diagram showing the boiler 101 according to this embodiment. The boiler 101 is an electrode-type boiler. The boiler 101 is an electrode-type once-through boiler.

[0010] 1 , 2 , 3 , and 4 , the boiler 101 includes water pipes 2, a lower header 3, an upper header 4, a riser pipe 5, an electrode 6, a neutral pipe 7, a feedwater line 8, a feedwater pump 9, a drain line 10, a drain valve 11, a steam line 12, a steam valve 13, a water level sensor 14, and a controller 15. In this embodiment, the boiler main body includes the water pipes 2, the lower header 3, and the upper header 4.

[0011] The water pipe 2 is a cylindrical member having a water flow path. Water is stored in the water pipe 2. The water pipe 2 is long in the Z-axis direction. Multiple water pipes 2 are provided. Each of the multiple water pipes 2 is arranged so that the central axis of the water pipe 2 is parallel to the Z-axis. The multiple water pipes 2 are arranged at intervals in the X-axis direction.

[0012] The lower header 3 communicates with the lower ends of each of the multiple water pipes 2. The lower header 3 stores water supplied from the water supply line 8. The lower header 3 distributes the water supplied from the water supply line 8 to each of the multiple water pipes 2. When water is supplied to the lower header 3, water is supplied to the water pipes 2. The water pipes 2 distribute the water from the lower header 3.

[0013] The upper header 4 communicates with the upper ends of the plurality of water pipes 2. The upper header 4 communicates with the upper ends of the water pipes 2 via riser pipes 5.

[0014] The riser pipe 5 connects the upper part of the water pipe 2 with the lower part of the upper header 4. The riser pipe 5 has a steam flow path. The riser pipe 5 circulates the steam generated in the water pipe 2. The steam generated in the water pipe 2 is supplied to the upper header 4 through the riser pipe 5.

[0015] The upper header 4 receives steam supplied from the water pipes 2 via the riser pipes 5. The upper header 4 collects the steam supplied from each of the plurality of riser pipes 5.

[0016] The electrodes 6 are arranged inside each of the multiple water tubes 2. The electrodes 6 are rod-shaped. The electrodes 6 are long in the vertical direction. In a plane perpendicular to the central axis of the water tubes 2, the outer shape of the electrodes 6 is circular. That is, the electrodes 6 are cylindrical and long in the Z-axis direction. The central axis of the electrodes 6 is parallel to the Z-axis. At least one pair of electrodes 6 is arranged inside each water tube 2. In this embodiment, three electrodes 6 are arranged inside each water tube 2. The three electrodes 6 are arranged parallel to each other inside the water tube 2. The three electrodes 6 are arranged spaced apart from each other inside the water tube 2. The dimensions of the three electrodes 6 are equal to each other. The dimensions of the electrodes 6 include the diameter (thickness) of the electrodes 6 and the dimension (length) in the Z-axis direction. The positions of the three electrodes 6 in the Z-axis direction are equal to each other.

[0017] 2 and 3, the electrodes 6 include a first electrode 6U, a second electrode 6V, and a third electrode 6W. In a plane perpendicular to the central axis of the water tube 2, the three electrodes 6 (6U, 6V, 6W) are arranged at the vertices of an imaginary equilateral triangle. In the plane perpendicular to the central axis of the water tube 2, the distance between the first electrode 6U and the second electrode 6V, the distance between the second electrode 6V and the third electrode 6W, and the distance between the third electrode 6W and the first electrode 6U are equal.

[0018] Three electrodes 6 are immersed in water inside the water tube 2. The electrodes 6 are in contact with the water inside the water tube 2. A voltage is input to the electrodes 6 immersed in the water. When a voltage is input to the electrodes 6, a current flows through the water contained in the water tube 2. When a current flows through the water, Joule heat is generated due to the electrical resistance of the water. The Joule heat causes the temperature of the water to rise, generating steam.

[0019] A neutral tube 7 is disposed around each of the three electrodes 6. The neutral tube 7 is made of metal. An example of a metal that forms the neutral tube 7 is iron. Three neutral tubes 7 are disposed inside one water tube 2. Inside one water tube 2, each of the three neutral tubes 7 is connected to each other. Inside one water tube 2, each of the three neutral tubes 7 is in contact with each other.

[0020] The neutral tube 7 is cylindrical and arranged around the electrode 6. The neutral tube 7 is long in the vertical direction. The central axis of the neutral tube 7 is parallel to the Z axis. The three neutral tubes 7 are arranged parallel to each other inside the water tube 2. The three neutral tubes 7 are arranged so as to be in contact with each other inside the water tube 2. The dimensions of the three neutral tubes 7 are equal to each other. The dimensions of the neutral tube 7 include the diameter (thickness) of the neutral tube 7 and the dimension (length) in the Z axis direction. The positions of the three neutral tubes 7 in the Z axis direction are equal to each other.

[0021] 2 and 3, the neutral tube 7 includes a first neutral tube 7U arranged around the first electrode 6U, a second neutral tube 7V arranged around the second electrode 6V, and a third neutral tube 7W arranged around the third electrode 6W. In a plane perpendicular to the central axis of the water tube 2, the first neutral tube 7U and the second neutral tube 7V are in contact, the second neutral tube 7V and the third neutral tube 7W are in contact, and the third neutral tube 7W and the first neutral tube 7U are in contact.

[0022] The electrode 6 is disposed at the center of the neutral tube 7. That is, the central axis of the electrode 6 coincides with the central axis of the neutral tube 7. If the distance between the outer peripheral surface of the electrode 6 and the inner peripheral surface of the neutral tube 7 in the radial direction of the central axis of the electrode 6 is defined as the radial distance, the radial distance is constant in the circumferential direction of the central axis of the electrode 6.

[0023] The three neutral pipes 7 are immersed in water inside the water pipe 2. The lower ends of the neutral pipes 7 are positioned at the same height as the lower ends of the electrodes 6. The lower ends of the neutral pipes 7 may also be positioned lower than the lower ends of the electrodes 6. The water in the water pipes 2 flows into the space between the outer peripheral surface of the electrodes 6 and the inner peripheral surface of the neutral pipes 7.

[0024] In this embodiment, the three electrodes 6 form a star connection with the neutral tube 7 as the neutral point.

[0025] The water supply line 8 is connected to the lower header 3. Water is supplied from a water supply source (not shown) to the water supply line 8. The water from the water supply source is supplied to the lower header 3 via the water supply line 8.

[0026] The feedwater pump 9 is disposed in the feedwater line 8. The feedwater pump 9 drives water from a water supply source to be supplied to the lower header 3 via the feedwater line 8.

[0027] A drain line 10 is connected to the lower part of the lower header 3. The water in the lower header 3 is discharged from the lower header 3 through the drain line 10.

[0028] A drain valve 11 is disposed in the drain line 10. When the drain valve 11 is opened, the water in the lower header 3 is drained through the drain line 10. When the drain valve 11 is closed, the discharge of water from the lower header 3 is stopped.

[0029] The steam line 12 is connected to the top of the upper header 4. The steam in the upper header 4 is discharged from the upper header 4 through the steam line 12.

[0030] The steam valve 13 is disposed on the steam line 12. When the steam valve 13 is opened, steam from the upper header 4 is discharged through the steam line 12. When the steam valve 13 is closed, the discharge of steam from the upper header 4 is stopped.

[0031] The water level sensor 14 detects the water level of the water pipe 2. The water level refers to the position of the water surface in the Z-axis direction.

[0032] The controller 15 includes a computer system. The controller 15 has a processor such as a CPU (Central Processing Unit), a main memory including a non-volatile memory such as a ROM (Read Only Memory) and a volatile memory such as a RAM (Random Access Memory), a storage, and an interface including an input / output circuit. The functions of the controller 15 are stored in the storage as a computer program. The processor reads the computer program from the storage, loads it into the main memory, and executes processing in accordance with the computer program. The computer program may be distributed to the controller 15 via a network.

[0033] The detection value of the water level sensor 14 is input to the controller 15. The controller 15 outputs control commands to control each of the feedwater pump 9, the drain valve 11, and the steam valve 13. The controller 15 controls each of the feedwater pump 9 and the drain valve 11 based on the detection value of the water level sensor 14 so that the water level in the water pipe 2 falls within a target range.

[0034] 4, power from a power system 16 is supplied to the electrodes 6 via a power supply circuit 17. A controller 15 outputs a control command for controlling the power supply circuit 17.

[0035] In this embodiment, four water tubes 2 are provided. A first electrode 6U is disposed in each of the four water tubes 2. A second electrode 6V is disposed in each of the four water tubes 2. A third electrode 6W is disposed in each of the four water tubes 2. As shown in FIG. 2 , the four first electrodes 6U are connected in parallel to a power supply circuit 17. The four second electrodes 6V are connected in parallel to the power supply circuit 17. The four third electrodes 6W are connected in parallel to the power supply circuit 17.

[0036] When a voltage is input to the three electrodes 6 (6U, 6V, 6W) by the power supply circuit 17, a current flows through the water between the electrodes 6 and the neutral tube 7 arranged around the electrodes 6. When a current flows through the water, Joule heat is generated due to the electrical resistance of the water. The Joule heat raises the temperature of the water, generating steam.

[0037] In this embodiment, the three electrodes 6 form a star connection with the neutral tube 7 as the neutral point. Therefore, in a cross section perpendicular to the central axis of the water tubes 2, current flows from all parts of the outer circumferential surface of the electrode 6 toward the neutral tube 7. For example, if the three electrodes 6 form a delta connection, current flows along the shortest route between a pair of adjacent electrodes. In this case, current is output from only a part of the outer circumferential surface of the electrode 6 in a cross section perpendicular to the central axis of the water tubes 2. Since only a part of the outer circumferential surface of the electrode 6 contributes to the generation of Joule heat, it becomes difficult to efficiently raise the temperature of the water. In this embodiment, the three electrodes 6 form a star connection with the neutral tube 7 as the neutral point. Therefore, the entire outer circumferential surface of the electrode 6 contributes to the generation of Joule heat. Therefore, the boiler 101 can efficiently raise the temperature of the water.

[0038] FIG. 5 is a perspective view schematically illustrating the electrode 6 and neutral tube 7 according to this embodiment. As shown in FIG. 5, in this embodiment, the inner surface (inner peripheral surface) of the neutral tube 7 and the outer surface (outer peripheral surface) of the neutral tube 7 are connected to each other. The neutral tube 7 has a plurality of openings 18 penetrating the inner and outer surfaces of the neutral tube 7. In the example shown in FIG. 5, the openings 18 are circular. In the example shown in FIG. 5, the neutral tube 7 includes a punched metal formed into a tubular shape. The openings 18 may be slit-shaped.

[0039] Air bubbles may be generated between the electrode 6 and the neutral tube 7. If air bubbles exist between the electrode 6 and the neutral tube 7, the flow of current between the electrode 6 and the neutral tube 7 may be obstructed. In this embodiment, the inner surface of the neutral tube 7 is connected to the outer surface of the neutral tube 7, so that air bubbles present between the electrode 6 and the neutral tube 7 are disposed outside the neutral tube 7 through the opening 18. Water surrounding the neutral tube 7 can flow between the electrode 6 and the neutral tube 7 through the opening 18.

[0040] The position and size of the opening 18 are optimally determined so that air bubbles between the electrode 6 and the neutral tube 7 are expelled and the water surrounding the neutral tube 7 flows into the space between the electrode 6 and the neutral tube 7. The porosity of the neutral tube 7 is determined so that it is not smaller than the area of ​​the counter electrode.

[0041] Second Embodiment A second embodiment will be described below. In the following description, components that are the same as or equivalent to those in the first embodiment described above will be denoted by the same reference numerals, and descriptions of those components will be simplified or omitted.

[0042] FIG. 6 is a cross-sectional view schematically showing a portion of a boiler 102 according to this embodiment. FIG. 7 is a perspective view schematically showing an electrode 60 and a neutral tube 70 according to this embodiment. In this embodiment, the electrode 60 has an upper support portion 61 and a plurality of comb-tooth portions 62 protruding downward from the upper support portion 61. The upper support portion 61 is annular. The upper support portion 61 has a pair of straight portions arranged to extend radially from the central axis of the water tube 2, and an arc portion connecting the outer edges of the pair of straight portions. The comb-tooth portions 62 are rod-shaped and extend downward from the lower surface of the upper support portion 61. A plurality of comb-tooth portions 62 are provided at intervals on the lower surface of the upper support portion 61.

[0043] A cavity extending in the vertical direction is formed inside the electrode 60. The cavity includes the space inside the annular upper support portion 61. The cavity also includes the space inside the multiple comb-tooth portions 62. Water from the water tube 2 is supplied to the cavity of the electrode 60.

[0044] The electrode 60 has a substantially cylindrical outer shape due to the multiple comb-tooth portions 62. The inner surface of the electrode 60 is in communication with the outer surface of the electrode 60. The inner surface of the electrode 60 is in communication with the outer surface of the electrode 60 through the gaps between the adjacent comb-tooth portions 62. When bubbles are generated in the cavity of the electrode 60, the bubbles in the cavity of the electrode 60 are discharged to the periphery of the electrode 60 through the gaps between the adjacent comb-tooth portions 62. Water around the electrode 60 flows into the cavity of the electrode 60 through the gaps between the adjacent comb-tooth portions 62.

[0045] The neutral pipe 70 includes a cylindrical member 70D and partition members 70A, 70B, and 70C connected to the cylindrical member 70D inside the cylindrical member 70D and dividing the interior of the cylindrical member 70D into three subspaces. The three partition members 70A, 70B, and 70C equally divide the interior of the cylindrical member 70D. That is, the three subspaces are equal in size and shape. One electrode 60 is disposed in each of the three subspaces.

[0046] In this embodiment, the water pipe 2 is disposed around the cylindrical member 70D.

[0047] In this embodiment, the three electrodes 60 also form a star connection with the neutral tube 70 as the neutral point, so that in a cross section perpendicular to the central axis of the water tube 2, current flows from all parts of the outer surfaces of the electrodes 60 toward the neutral tube 7. Since the entire outer surface of the electrodes 60 contributes to the generation of Joule heat, the boiler 102 can efficiently raise the temperature of the water.

[0048] 8 is a perspective view schematically illustrating an electrode 60 according to this embodiment. As shown in FIG. 8, the electrode 60 has an upper support portion 61, a plurality of comb-tooth portions 62 protruding downward from the upper support portion 61, and a lower support portion 63 connected to each of the lower ends of the plurality of comb-tooth portions 62. The size and shape of the lower support portion 63 are the same as those of the upper support portion 61. As shown in FIG. 8, the lower ends of the comb-tooth portions 62 may be fixed to the lower support portion 63.

[0049] Third Embodiment A third embodiment will now be described. In the following description, components that are the same as or equivalent to those in the first embodiment described above will be denoted by the same reference numerals, and descriptions of those components will be simplified or omitted.

[0050] Fig. 9 is a cross-sectional view schematically showing a part of the boiler 103 according to this embodiment. Fig. 10 is a perspective view schematically showing the electrode 64 and the neutral tube 70 according to this embodiment. The neutral tube 70 according to the third embodiment is the same as the neutral tube 70 described in the second embodiment, and therefore its description will be omitted.

[0051] In this embodiment, the electrode 64 is solid. That is, unlike the electrode 60 described in the second embodiment, the electrode 64 does not have a cavity. The electrode 64 is formed by dividing a single cylindrical electrode into three equal parts along a plane perpendicular to the central axis of the water pipe 2. One electrode 64 is disposed in each of the three subspaces of the neutral pipe 70.

[0052] In this embodiment, the water tubes 2 are not arranged around the tubular member 70D. That is, the boiler body according to this embodiment does not include the water tubes 2. The boiler body according to this embodiment includes the tubular member 70D in which water is stored. If the inner and outer surfaces of the tubular member 70D are not connected and the partial space of the neutral tube 70 can hold water, the water tubes 2 may be omitted.

[0053] In this embodiment, the three electrodes 64 also form a star connection with the neutral tube 70 as the neutral point, so that the entire outer surface of the electrodes 64 contributes to the generation of Joule heat. Therefore, the electrode-type boiler 103 can efficiently raise the temperature of the water.

[0054] Fourth Embodiment A fourth embodiment will now be described. In the following description, the same or equivalent components as those in the first embodiment will be denoted by the same reference numerals, and the description of those components will be simplified or omitted.

[0055] Fig. 11 is a front view schematically showing a boiler 104 according to this embodiment. Fig. 12 is a cross-sectional view schematically showing the boiler 104 according to this embodiment. In this embodiment, there are three water tubes 2. An electrode 65 is disposed inside each of the water tubes 2. In this embodiment, one electrode 65 is disposed inside each water tube 2.

[0056] A neutral tube 75 is disposed around each of the three electrodes 65. One neutral tube 75 is disposed inside one water tube 2. The electrode 65 is disposed in the center of the neutral tube 75. The three neutral tubes 75 are interconnected via a connecting cable.

[0057] The three electrodes 65 are connected in parallel to the power supply circuit 17. In this embodiment as well, the three electrodes 65 form a star connection with the neutral tube 75 as the neutral point.

[0058] [Other Embodiments] In the first embodiment described above, the neutral pipe 7 is cylindrical. The neutral pipe 7 does not have to be cylindrical. That is, in a plane perpendicular to the central axis of the water pipe 2, the neutral pipe 7 does not have to be circular, and may be polygonal, such as rectangular or hexagonal.

[0059] The components described in each of the above embodiments can be combined as appropriate. For example, an electrode 60 having a hollow portion as described in the second embodiment may be disposed inside the neutral tube 7 described in the first embodiment. Alternatively, the electrode may have a cylindrical outer shape and be provided with an opening that connects the inner and outer circumferential surfaces of the electrode. The electrode may include a punched metal formed in a tubular shape.

[0060] [Contribution to the United Nations-led Sustainable Development Goals (SDGs)] This disclosure includes matters that contribute to the realization of SDG Goal 12, "Responsible Consumption and Production," and Goal 13, "Take urgent action to combat climate change."

[0061] DESCRIPTION OF SYMBOLS 2...Water pipe 3...Lower header 4...Upper header 5...Rising pipe 6...Electrode 6U...First electrode 6V...Second electrode 6W...Third electrode 7...Neutral pipe 7U...First neutral pipe 7V...Second neutral pipe 7W...Third neutral pipe 8...Feedwater line 9...Feedwater pump 10...Drain line 11...Drain valve 12...Steam line 13...Steam valve 14...Water level sensor 15...Controller 16...Power system 17...Power supply circuit 18...Opening 60...Electrode 61...Upper support part 62...Comb tooth part 63...Lower support part 64...Electrode 65...Electrode 70...Neutral pipe 70A...Partition member 70B...Partition member 70C...Partition member 70D...Cylindrical member 75...Neutral pipe 101...Boiler 102...Boiler 103...Boiler 104...Boiler

Claims

1. An electrode boiler comprising: a boiler body containing water; three electrodes arranged inside the boiler body and immersed in the water; and neutral tubes arranged around each of the three electrodes, wherein the three neutral tubes are interconnected, and the three electrodes form a star connection with the neutral tube as the neutral point.

2. An electrode boiler as described in claim 1, wherein the electrodes are rod-shaped and long in the vertical direction, the three electrodes are arranged parallel to each other, and the electrode is arranged at the center of the neutral tube.

3. An electrode boiler as described in claim 2, wherein the lower end of the neutral tube is positioned at the same height as or lower than the lower end of the electrode.

4. An electrode boiler as described in claim 1, wherein the neutral tube has a plurality of openings penetrating the inner and outer surfaces of the neutral tube.

5. An electrode boiler as described in claim 4, wherein the neutral tube comprises a punched metal formed into a tubular shape.

6. An electrode boiler as claimed in claim 1, wherein a cavity extending in the vertical direction and into which the water is supplied is formed inside the electrode.

7. An electrode boiler as claimed in claim 1, wherein the inner surface of the electrode and the outer surface of the electrode are in communication with each other.

8. An electrode boiler as described in claim 1, wherein the neutral tube is cylindrical and disposed around the electrode.

9. An electrode boiler as described in claim 1, wherein the neutral tube comprises a cylindrical member and a partition member connected to the cylindrical member inside the cylindrical member and dividing the inside of the cylindrical member into three subspaces, and the electrodes are arranged one in each of the three subspaces.

10. An electrode boiler as set forth in claim 9, wherein the boiler body has a water tube arranged around the cylindrical member.

11. An electrode boiler as described in claim 1, wherein the boiler body includes a plurality of water tubes in which water is accommodated, the electrode is disposed inside one of the water tubes, the neutral tube is disposed inside one of the water tubes, and the plurality of neutral tubes are connected to each other via a connecting cable.

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