JP5691830B2 - Induction heating steam generator - Google Patents

Description

  The present invention relates to an induction heating steam generator that heats water by induction heating to generate steam, particularly superheated steam.

  Induction heating type steam generators are well known from Patent Documents 1 and 2 and the like.

  The steam obtained by such an induction heating type steam generator is called wet steam in which water gas molecules and liquid molecules are mixed. If it is used as it is, it becomes a poor quality steam that is likely to generate drainage. Therefore, in order to obtain a dry, high quality steam, it is necessary to separate the moisture from the steam and dry the steam.

  As an induction heating type steam generator equipped with such a steam / water separator for steam, those shown in Patent Documents 3 and 4 are known.

  The steam generator described in Patent Document 3 is provided with a steam / water separation means on the outside, but the steam generation device described in Patent Document 4 is provided with a steam / water separation means on the inside. It has been improved.

  FIG. 9 shows the configuration of a conventional induction heating steam generator described in Patent Document 4.

  The conventional induction heating steam generator 1 shown in FIG. 9 includes a heating container 10, an induction heating coil 20, and a shield coil 30. The heating container 10 includes a steam header 16 and a water supply header 17 that are formed of a lid made of a non-magnetic metal such as stainless steel, and heat generation that is composed of small pieces of magnetic conductive material. It comprises a plurality of heating tubes 15 constituted by thin tubes made of non-metallic heat-resistant material such as ceramics or glass filled with a large number of bodies 13. The plurality of heating tubes 15 are hermetically coupled and supported by flanges 18 and 19 made of nonmagnetic metal such as stainless steel at both upper and lower ends. The steam header 16 and the water supply header 17 are hermetically joined to the flanges 18 and 19, respectively, so that the entire heating container 10 is hermetically configured. Further, a heat insulating container 10a made of a non-conductive heat-resistant material is provided on the entire outer periphery of the heating tube 15, and the heat insulating material 10b is provided in a space between the heating tubes and a space between the heating tube and the heat insulating container in the container. Filled.

  When water W is supplied from the water supply source to the water supply header 17 through the water supply pipe 41, stored in the heating pipe 15 of the heating container 10, and high-frequency heating power is supplied to the heating coil 20, the heating element 13 in the heating pipe 15 becomes electromagnetic. The heat is generated by induction heating, and the water in the heating tube 15 is heated by this heat to generate steam. The steam generated in the heating pipe 15 rises in the pipe and is discharged into the steam header 16 at the upper part of the heating container 10 from the opening 15a at the upper end of the pipe.

  Each of the heating pipes 15 in the steam header 16 is provided with a guide body 9 for guiding the flow of the discharged steam so that the steam discharged from each heating pipe 15 into the steam header 16 flows as a swirling flow in a certain direction. The steam header 16 is provided with a steam gas-liquid separation function by being provided in the vicinity of the steam outlet at the upper end of each. That is, the steam S discharged vertically from the heating tube 15 is bent at an inclination angle by the inclined upper surface plate of the guide body 9 and directed obliquely upward, and is directed toward the front opening by the surrounding wall of the guide body 9. In the tangential direction of the inner periphery of the peripheral wall a of the steam header 16. Thereby, the steam S discharged from the heating pipe 15 to the steam header 16 flows in the steam header 16 while turning in a clockwise direction, for example, and the steam turns into the space above the guide body 9 of the steam header 16. A flow is formed. In this way, moisture and gas components in the wet steam S containing moisture are separated by the centrifugal force acting on the steam in the process of the steam S swirling and flowing in the steam header 16, and the moisture falls due to gravity. Thus, the steam returned to the heating tube 15 remains in the steam header 16 with dried steam from which moisture has been removed.

  The dried steam S from which moisture has been removed is taken out from a steam outlet pipe 14 connected to a steam outlet 16b provided in the steam header 16 and supplied to the cooling water passages of the coil conductors of the heating coil 20 and the shield coil 30. Then, in the process of flowing here, it is reheated by the Joule heat of each coil conductor and is taken out from the superheated steam extraction pipe 62 as superheated steam S ′. Since this superheated steam S ′ is a superheated dry steam S from which moisture has been removed, it becomes a dry high-quality superheated steam.

JP 2002-022107 A International Publication No. WO98 / 29685 Japanese Patent No. 3758668 Japanese Patent No. 4552851

  Such a conventional induction heating type steam generator has an advantage that the apparatus can be miniaturized because the steam header of the heating container has a gas-liquid separation function for taking out the dry steam.

  On the other hand, since the heating tube that generates steam is configured by filling a ceramic or glass non-metallic thin tube with a heating element made of a magnetic metal piece, the heating tube is joined to a metal water supply header or steam header by welding. Can not do it. For this reason, it is necessary to seal the joint portion between the heating pipe and the water supply header and steam header with a packing material that can withstand high temperatures and high pressures. Therefore, there is an inconvenience that the maintenance of the seal portion is troublesome.

  The present invention solves such inconvenience and enables welding of the heating pipe that generates steam, the water supply header, and the steam header so that the manufacturing cost is low and maintenance is not required. It is an object of the present invention to provide an induction heating steam generator capable of supplying high quality dry superheated steam.

  In order to solve such a problem, the present invention includes a plurality of heating pipes that are internally passed, and a water supply header that is connected to and connected to the lower ends of the plurality of heating pipes to supply water to the heating pipes. A steam header coupled to and connected to the upper ends of the plurality of heating tubes to collect and take out the steam generated in each heating tube; and an induction heating coil that surrounds the plurality of heating tubes from the outside and performs electromagnetic induction heating And a shield coil that is disposed outside the induction heating coil so as to surround it, shields the magnetic flux leaking from the conductive heating coil, and allows the steam taken out from the steam header to flow inside and heats it. The plurality of heating pipes are each formed of a magnetic conductive metal pipe, and the steam header is formed of a metal sealed container having a circular outer periphery. The upper end of the heating pipe coupled to at least the circular outer circumference of the steam header of the plurality of heating pipes is configured so that the steam discharged from the heating pipe into the steam header has a swirl flow in a certain direction. The heating pipe and the steam header are hermetically sealed by welding in a direction in which steam is discharged from the heating pipe to the steam header in the same direction with respect to the radial direction of the steam header. It is characterized by being connected in communication.

  In this invention, the lower end of the plurality of heating pipes can be coupled to the water supply header via a flexible pipe.

  In the present invention, it is preferable that the upper end and the lower end of the shield coil have substantially the same height as the upper end and the lower end of the induction heating coil. At that time, the number of turns of the shield coil is an even number.

  According to this invention, in the induction heating type steam generator, since the plurality of heating pipes are formed of magnetic conductive metal pipes, the heating pipes can be welded and joined to the water supply header and the steam header arranged vertically. In addition, it is not necessary to provide a seal at the joint between the header and the header of the heating tube, which not only simplifies the engagement structure, but also eliminates the need for maintenance of the seal. Then, the steam pipe is collected on the steam header for collecting and taking out the steam, and the steam pipe is welded to the steam header by welding and joining the steam pipe in the same direction with respect to the radial direction of the steam header. Therefore, since the steam drum for separating air and water which is conventionally required is not necessary, the apparatus can be reduced in size. The water separated by the steam header falls as it is, is returned to each heating tube of the heating container, and is reheated to become steam.

BRIEF DESCRIPTION OF THE DRAWINGS The front view which shows the structure of the principal part of the induction heating type steam generator of Example 1 of this invention. The top view which shows the structure of the principal part of the induction heating type steam generator of Example 1 of this invention. BRIEF DESCRIPTION OF THE DRAWINGS The longitudinal cross-sectional view which shows the structure of the principal part of the induction heating type steam generator of Example 1 of this invention. The plane sectional view which meets the IV-IV line of the steam header 12 of FIG. The front view which shows the structure of the shield coil used for the induction heating type steam generator of Example 1 of this invention. The system configuration | structure figure of the induction heating type steam generator of Example 1 of this invention. The structure of the connection part of the heating pipe and steam header of the induction heating type steam generator of Example 2 of this invention is shown, (a) is a partial longitudinal cross-sectional view, (b) is a partial cross-sectional view. The structure of the connection part of the heating pipe and steam header of the induction heating type steam generator of Example 3 of this invention is shown, (a) is a partial longitudinal cross-sectional view, (b) is a partial cross-sectional view. The longitudinal cross-sectional view which shows the structure of the conventional induction heating type steam generator.

  Embodiments of the present invention will be described with reference to the embodiments shown in the drawings.

  1 to 6 show an induction heating steam generator according to Embodiment 1 of the present invention.

  A heating container 10 of the induction heating steam generator 1 of the first embodiment includes a plurality of heating tubes 11 formed of a magnetic conductive metal, for example, a metal tube made of magnetic stainless steel such as SUS430 or 440, and the heating tube 11. A steam header 12 is connected to the upper end of the pipe 11 and collects steam generated in the heating pipe 11, and a water supply header 17 is connected to the lower end of the heating pipe 11 and supplies water to the heating pipe 11.

  Here, the steam header 12 is formed of a metal tube made of a material such as non-magnetic stainless steel into a circular shape so that the outer periphery is circular (see FIG. 2). If the water supply header 17 is a box-shaped airtight container, the outer shape may be circular or rectangular, but here it is rectangular.

  The heating tube 11 is approximated to the shape of a donut-shaped steam header 12, and a plurality of tubes are divided into an outer side and an inner side and arranged in a double ring shape (see FIG. 2). And the upper end of each pipe | tube of the heating pipe | tube 11 penetrates this to the circular outer peripheral wall and inner peripheral wall of the doughnut-shaped steam header 12, and is secretly couple | bonded by welding as shown in FIG. And each pipe | tube of the heating pipe | tube 11 inclines and couple | bonds with the outer peripheral wall and inner peripheral wall of the steam header 12 in the fixed direction with respect to the radial direction of a steam header. Steam to be discharged is discharged inclining in the same direction with respect to the radial direction of the steam header. Thereby, the steam discharged from the heating pipe 11 into the steam header 12 forms a swirling flow therein. Since the heating pipe 11 and the steam header 12 are joined together by welding, it is not necessary to seal the joining portion, and the joining structure is simplified.

  The lower end of the heating tube 11 may be directly coupled to the water supply header 17 so as to communicate therewith, but in order to facilitate assembly and to relieve stress due to the thermal expansion of the heating tube 11 itself, It is good to couple | bond with the water supply header 17 through the flexible metal pipe | tube 11c marketed as a bull tube.

  In order to shield the magnetic flux leaking from the induction heating coil 20 by arranging the induction heating coil 20 around the outside of the plurality of heating tubes 11 of the heating container 10 and further surrounding the outside of the induction heating coil 20. The shield coil 30 is arranged.

  The induction heating coil 20 is configured by winding a tubular conductor having a cooling water flow passage formed in a conductive material such as low resistance copper or the like into a cylindrical shape for a required turn.

  Further, the shield coil 30 is also formed in a cylindrical shape by winding a plurality of turns (here, 6 turns) of a tubular conductor 31 having a cooling water flow path inside, and as shown in FIG. By short-circuiting the conductors with a short-circuit plate 32 made of an electric conductor, each turn constitutes an independent, electrically closed circuit. Of the shield coil 30, the upper end and the lower end of the turn having a large diameter are substantially located at the upper end and the lower end of the induction heating coil 20, and the conductors of each turn are separated from each other as appropriate.

  The water supply system and the steam extraction system in the steam generator 1 configured as described above are configured as shown in FIG.

  That is, a reservoir tank 71 is provided, and water W supplied from a water supply or a deionized water device or the like is temporarily stored therein. The water W stored in the reservoir tank 71 is supplied from the water supply port 71a to the cooling water inlet 20a of the induction heating coil 20 through the piping by the water supply pump 72 as shown by the solid line arrow. The water W supplied to the induction heating coil 20 is preheated in the course of cooling the coil conductor through the cooling water flow passage in the coil conductor, and the piping from the cooling water outlet 20b of the induction heating coil 20 is routed. To the water supply port 17 a of the water supply header 17.

  The water supply header 17 and the steam header 12 are communicated with each other via a plurality of heating pipes 11.

  The steam S stored in the steam header 12 is supplied from the steam outlet 12c at the upper end to the cooling water inlet 30a of the shield coil 30 through the pipe 14, as indicated by a dotted arrow. This steam is heated in the process of cooling the coil conductor through the cooling water passage in the coil conductor of the shield coil 30 and becomes superheated steam from the steam outlet 30b of the shield coil 30 to the steam extraction pipe 62. From here, it is further sent to a place where steam is used through a pipe (not shown).

  Further, the water supply header 17 and the steam header 12 are connected to a water level detection pipe 73 formed of a transparent heat-resistant pipe so that they communicate with each other. Since the water level in the water level detection pipe 73 shows the same level as the water level in the heating pipe 11, a water level detector 74 that photoelectrically detects the water level is disposed opposite to the set water level L of the detection pipe 73. The water level in the heating container 10 is detected. By controlling the operation of the pump 72 by the detection signal of the water level detector 74, adjustment is performed so that the water level in the heating container 10 is always kept at a set constant water level.

  In order to generate steam by such an induction heating steam generator 1, first, water is supplied from the reservoir tank 71 by the pump 72, and water W is stored until the water level L set in advance in the water supply header 17 and the heating pipe 11 is reached. Then, supply of high-frequency heating power to the induction heating coil 20 from a high-frequency AC power source (not shown) is started.

  As a result, the heating tube 11 is induction-heated electromagnetically by the high-frequency magnetic field generated by the induction heating coil 20, and the water in the heating tube 11 is heated by this heat to generate steam. The steam generated in the heating pipe 11 rises in the pipe and is discharged into the steam header 12 at the upper part of the heating container 10 from the opening 11a at the upper end of the pipe.

  The steam S discharged from the heating pipe 11 into the steam header 12 is coupled with the upper end of the heating pipe 11 inclined at a certain angle to the inner and outer peripheral walls of the steam header. Therefore, as shown by the dotted arrow in FIG. From the opening 11a, the steam header 12 is discharged while being inclined with respect to the radial direction of the inner and outer peripheral walls. For this reason, the steam discharged from the heating pipe 11 flows in the steam header 12 while turning counterclockwise along the inner and outer peripheral walls 12 a and 12 b, and a swirling flow of steam is formed in the steam header 12. The In this way, moisture and gas components in the wet steam S including moisture are separated by the centrifugal force that acts on the steam while the steam S is swirling and flowing in the steam header 12, and the moisture falls due to gravity and is heated. Since it is returned to the tube 11, dry steam from which moisture has been removed remains in the steam header 11.

  The dried steam S from which moisture has been removed is taken out from the steam outlet pipe 14 connected to the steam outlet 12c provided in the steam header 12, and supplied to the cooling water passage of the coil conductor of the shield coil 30. In the process of cooling the flowing coil conductor, it is reheated by Joule heat of each coil conductor to become superheated steam S ′, and is taken out from the superheated steam take-out pipe 62. Since this superheated steam S ′ is a superheated dry steam S from which moisture has been removed, it is dried to become a high-quality superheated steam.

  In this invention, the shield coil 30 reheats the steam generated in the heating container 10 to generate superheated steam in addition to the function of shielding the magnetic flux leaking from the induction heating coil 20 to prevent leakage. Therefore, it becomes a high temperature of 300 ° C. or higher and thus receives a large thermal stress. In particular, since the leakage magnetic flux density is high in the central portion of the induction heating coil 20 in the axial direction, the shield coil conductor disposed in this portion is subjected to a large thermal stress that is higher in temperature.

  The number of turns of the shield coil 30 is set to an even number so that the intervals between the respective winding (turn) conductors are substantially equal, and the shield coil 30 is avoided from being arranged near the central portion in the axial direction of the induction heating coil 20. As a result, the conductors constituting each closed circuit generate heat uniformly and receive substantially uniform thermal stress.

  In FIG. 7, the structure of the principal part of the heating container 10 of the induction heating type steam generator 1 by Example 2 of this invention is shown.

  In the second embodiment, a joint portion between the heating pipe 11 and the steam header 12 of the heating container 10 is modified. The heating tubes 11 arranged on the outer side are connected to the outer peripheral wall 12a of the steam header 12 in an inclined manner as in the first embodiment, but the heating tubes 11 'arranged on the inner side are perpendicular to the bottom of the steam header 12. Are connected.

  When the heating pipe is coupled vertically to the steam header 12 without inclining, the drilling process of the hole for coupling the 12 heating pipes to the steam header is easier than when obliquely drilled.

  The steam discharged into the steam header 12 from the heating pipe 11 ′ that is vertically coupled to the steam header 12 does not form a swirl flow, but together with the swirl flow of the steam discharged from the outer heating pipe 11 that is coupled at an angle. It will turn, and all the steam in the steam header 12 will turn in this.

  For this reason, also in the steam header 12 of the heating container 10 of Example 2, the vapor-liquid separation function of steam is exhibited.

  In FIG. 8, the structure of the principal part of the heating container 10 of the induction heating type steam generator 1 by Example 3 of this invention is shown.

  In the third embodiment, the shape of the steam header is converted. In the first and second embodiments, the steam header 12 is formed of a donut-shaped airtight container, but the steam header 12 ′ of the third embodiment has a structure as shown in FIGS. 8 (a) and 8 (b). The outer periphery is formed of a sealed casing-like container having a circular shape.

  In the outer peripheral wall 12′a of the steam header 12 ′, steam is discharged from the heating pipe 11 obliquely into the steam header 12 ′ so that a swirl flow in a certain direction is formed therein. As in the case of No. 2, the heating tubes 11 arranged outside are inclined and coupled. Heating tubes 11 ′ arranged on the inside are vertically coupled to the bottom of the steam header 12.

  Also in the steam header 12 'of the third embodiment, as with the steam header 12 of the second embodiment, the steam discharged from the heating pipe forms a swirling flow in a certain direction, and the steam is moistened by the centrifugal force generated by this swirling flow. Water is separated from the water, and dry steam can be generated.

DESCRIPTION OF SYMBOLS 1 Induction heating type steam generator 10 Heating container 11, 11 'Heating pipe 12, 12' Steam header 17 Water supply header 20 Induction heating coil 30 Shield coil

Claims (4)

  A plurality of heating pipes that pass through the inside, a water supply header that is connected to and connected to the lower ends of the plurality of heating pipes, and supplies water to the heating pipes, and that communicates with the upper ends of the plurality of heating pipes A steam header that collects and extracts steam generated in each heating tube, an induction heating coil that surrounds the plurality of heating tubes from the outside and performs electromagnetic induction heating, and surrounds the induction heating coil so as to surround it In the induction heating type steam generator comprising: a shield coil that is arranged and shields magnetic flux leaking from the conductive heating coil, and causes the steam taken out from the steam header to flow inside and heats the steam, Each of the heating pipes is formed of a magnetic conductive metal pipe, and the vapor header is formed of a metal hermetic container having a circular outer periphery, and at least the plurality of heating pipes An upper end of a heating pipe coupled to a circular outer periphery of the gas header is arranged so that the steam discharged from the heating pipe into the steam header forms a swirling flow in a certain direction therein. Inductive heating characterized in that the heating pipe and the steam header are connected in an airtight manner by joining by welding in a direction in which steam is discharged in an inclined direction in the same direction with respect to the radial direction of the steam header. Steam generator.   The induction heating steam generator according to claim 1, wherein lower ends of the plurality of heating pipes are coupled to the feed header through flexible pipes.   3. The induction heating steam generator according to claim 1, wherein an upper end and a lower end of a turn having a large diameter of the shield coil have substantially the same height as an upper end and a lower end of the induction heating coil. Heating steam generator.   The induction heating steam generator according to claim 3, wherein the number of turns of the shield coil is an even number.

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