Superheated steam generation device, and method of manufacturing conductor pipe used for superheated steam generation device

Abstract

To prevent heat degradation of a conductor pipe by reducing a contraction action due to heat stress, and localized heating.SOLUTION: A induction-heated conductor pipe 2 has an introduction side shortened part 21 formed to be axially shortened in a side of introducing water or steam, a derivation side shortened part 22 formed to be axially shortened in a side of deriving superheated steam, and a spiral connection pipe part 23 connecting the introduction side shortened part 21 and the derivation side shortened part 22 and not being axially shortened.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a superheated steam generator and a method for manufacturing a conductor tube used in the superheated steam generator. [Background technology]

[0002] As a conventional superheated steam generator, as shown in Patent Document 1, a spiral conductor tube is integrated by short-circuiting over the entire axial direction.

[0003] However, in a configuration in which the entire axial direction of the conductor tube is short-circuited by welding, the central part of the axial direction of the conductor tube is overheated (to an abnormally high temperature) by induction heating, and in the worst case scenario, the conductor tube may melt. In addition, metal fatigue occurs in the conductor tube due to contraction caused by thermal stress, and in the worst case scenario, the conductor tube may break and cause steam to leak. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-113282 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made to solve the above problems, and has as its main object to suppress thermal deterioration of the conductor tube by reducing the shrinkage action and localized heating caused by thermal stress. [Means for solving the problem]

[0006] In other words, the superheated steam generating device of the present invention is a superheated steam generating device that inductively heats a spirally wound cylindrical conductor tube using a magnetic flux generating mechanism to heat the water or steam flowing through the conductor tube to generate superheated steam, and is characterized in that the conductor tube has an inlet side short-circuit section formed by short-circuiting in the axial direction on the inlet side of the steam, an outlet side short-circuit section formed by short-circuiting in the axial direction on the outlet side of the superheated steam, and a spiral connecting tube section that connects the inlet side short-circuit section and the outlet side short-circuit section and is not short-circuited in the axial direction.

[0007] In this case, since the conductor tube is divided into an inlet-side short-circuit section and an outlet-side short-circuit section by the spiral connecting tube section, it is possible to reduce the contraction action due to thermal stress and also to reduce local overheating of the conductor tube. As a result, it is possible to suppress thermal deterioration of the conductor tube. Furthermore, by making the inlet-side short-circuit section a low-temperature range and the outlet-side short-circuit section a high-temperature range, it is possible to use different materials for the inlet-side short-circuit section, for example, ordinary steel and the outlet-side short-circuit section a heat-resistant steel, which also makes it possible to reduce costs.

[0008] In order to simplify the structure of the conductor pipe, it is desirable that the introduction side short-circuit portion, the outlet side short-circuit portion and the connection pipe portion are integrally formed.

[0009] Furthermore, a method for manufacturing a conductor tube according to the present invention is a method for manufacturing a conductor tube used in a superheated steam generator that generates superheated steam by inductively heating a cylindrical conductor tube wound in a spiral shape using a magnetic flux generating mechanism, and heating water or steam flowing through the conductor tube, and is characterized in that a helical conductor tube is formed by bending a straight conductor tube, one end of the helical conductor tube is short-circuited in the axial direction to form a one-end short-circuit portion, the other end of the helical conductor tube is short-circuited in the axial direction to form an other-end short-circuit portion, and a helical connecting tube portion is formed between the one-end short-circuit portion and the other-end short-circuit portion without short-circuiting in the axial direction. Effect of the Invention

[0010] According to the present invention thus configured, it is possible to reduce the shrinkage action and local heating caused by thermal stress, thereby suppressing thermal deterioration of the conductor tube. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram showing a configuration of a superheated steam generator according to one embodiment of the present invention. [Diagram 2] 3A is a top view of a conductor tube in the same embodiment, and FIG. 3B is a front view of the conductor tube. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a superheated steam generating device according to the present invention will be described with reference to the drawings.

[0013] <1.Device configuration> The superheated steam generator 100 according to this embodiment heats steam generated externally to generate superheated steam above 100° C. (200° C. to 2000° C.) Note that the steam generated externally may be an induction heating type steam generator, an electrically heated type steam generator, or a boiler type steam generator.

[0014] Specifically, the superheated steam generator 100 includes a spirally wound conductor pipe 2 and a magnetic flux generating mechanism 3 that inductively heats the conductor pipe 2, as shown in Figs.

[0015] The conductor tube 2 is formed into a cylindrical shape by spirally winding a conductive tube and is short-circuited in the axial direction, and has an inlet port P1 for introducing steam and an outlet port P2 for discharging superheated steam. The wound portions of the conductor tube 2 corresponding to one turn are in contact with or close to each other. The conductor tube 2 can be made of, for example, austenitic stainless steel or Inconel alloy. The detailed structure of the conductor tube 2 will be described later.

[0016] The magnetic flux generating mechanism 3 is provided inside and outside the conductor tube 2 to inductively heat the conductor tube 2, and has an induction coil 31 provided along the inner surface and side surface of the conductor tube 2. The magnetic flux generating mechanism 3 may also have a magnetic path forming member 32 such as an iron core. An AC voltage is applied to the induction coil 31 by an AC power source of commercial frequency (50 Hz or 60 Hz).

[0017] In the superheated steam generator 100 configured as described above, an induced current flows through the conductor tube 2 by applying an AC voltage of 50 Hz or 60 Hz to the induction coil 31, causing the conductor tube 2 to generate Joule heat. Then, the steam flowing through the conductor tube 2 receives heat from the inner surface of the conductor tube 2 and is heated, generating superheated steam.

[0018] <Detailed configuration of conductor tube 2> Next, a specific configuration of the conductor tube 2 of this embodiment will be described.

[0019] 2, the conductor pipe 2 of this embodiment has an inlet-side short-circuit section 21 formed by short-circuiting in the axial direction on the inlet side of the steam, an outlet-side short-circuit section 22 formed by short-circuiting in the axial direction on the outlet side of the superheated steam, and a spiral connecting pipe section 23 that connects the inlet-side short-circuit section 21 and the outlet-side short-circuit section 22 and is not short-circuited in the axial direction. In this embodiment, the inlet-side short-circuit section 21, the outlet-side short-circuit section 22, and the connecting pipe section 23 are integrally formed. In other words, the conductor pipe 2 is composed of a single conductor pipe.

[0020] The introduction side short circuit portion 21 is formed by short-circuiting multiple turns of the helical element in the axial direction. The helical element is a conductor tube portion that corresponds to one turn of the helix. The introduction side short circuit portion 21 of this embodiment is formed by short-circuiting multiple turns of the helical element, including the helical element connected to the introduction port P1, in the axial direction. Here, the multiple turns of the helical elements are configured to be in contact with or close to each other. Also, the multiple turns of the helical elements are short-circuited by welding adjacent helical elements.

[0021] The outlet-side short-circuit portion 22 is formed by short-circuiting a plurality of turns of helical elements in the axial direction. In this embodiment, the outlet-side short-circuit portion 22 is formed by short-circuiting a plurality of turns of helical elements, including the helical element connected to the outlet port P2, in the axial direction. Here, the plurality of turns of helical elements are configured to be in contact with or close to each other. In addition, the plurality of turns of helical elements are short-circuited by welding adjacent helical elements.

[0022] The connecting pipe section 23 connects the downstream spiral element in the inlet-side short-circuit section 21 and the upstream spiral element in the outlet-side short-circuit section 22. In other words, the inlet-side short-circuit section 21 and the outlet-side short-circuit section 22 are connected in series. The spiral element constituting the connecting pipe section 23 may be less than one turn, may be one turn, or may be multiple turns. This connecting pipe section 23 has the function of absorbing thermal stress in the inlet-side short-circuit section 21 and the outlet-side short-circuit section 22.

[0023] Next, a method for manufacturing the conductor tube 2 of this embodiment will be described. First, a straight conductor tube is bent to form a helical conductor tube 2. Here, the portion of the helical conductor tube 2 that becomes the introduction-side short-circuit portion 21 is formed so that multiple turns of helical elements are in contact with or close to each other, and the portion that becomes the outlet-side short-circuit portion 22 is formed so that multiple turns of helical elements are in contact with or close to each other. Note that the portion that becomes the connection tube portion 23 is formed so as to be separated from the helical elements that become the introduction-side short-circuit portion 21 and so as to be separated from the helical elements that become the outlet-side short-circuit portion 22.

[0024] Next, one end side (part that will become the introduction side short-circuit portion 21) of the helical conductor tube 2 is short-circuited in the axial direction by welding or the like to form the one-end short-circuit portion (introduction side short-circuit portion 21). Also, the other end side (part that will become the outlet side short-circuit portion 22) of the helical conductor tube 2 is short-circuited in the axial direction by welding or the like to form the other-end short-circuit portion (outlet side short-circuit portion 22). Furthermore, the one-end short-circuit portion (introduction side short-circuit portion 21) and the other-end short-circuit portion (outlet side short-circuit portion 22) are not short-circuited in the axial direction between them to form the helical connection tube portion 23.

[0025] <Effects of this embodiment> In the superheated steam generator 100 configured in this manner, the conductor pipe 2 is divided into the inlet-side short-circuit portion 21 and the outlet-side short-circuit portion 22 by the helical connecting pipe portion 23, so that it is possible to reduce the contraction action due to thermal stress and also to reduce local overheating of the conductor pipe 2. As a result, it is possible to suppress thermal deterioration of the conductor pipe 2. Furthermore, by making the inlet-side short-circuit portion 21 a low-temperature region and the outlet-side short-circuit portion 22 a high-temperature region, it is possible to use different materials, such as ordinary steel for the inlet-side short-circuit portion 21 and heat-resistant steel for the outlet-side short-circuit portion 22, and therefore it is also possible to reduce costs.

[0026] <Other Modified Embodiments> For example, in the above embodiment, two short-circuit portions (an introduction side short-circuit portion and an outlet side short-circuit portion) are formed in one conductor tube 2, but it may also be configured such that three or more short-circuit portions are formed.

[0027] Also, the introduction-side short-circuit portion 21 and the outlet-side short-circuit portion 22 may have different pipe diameters. The number of turns (the number of helical elements) of the introduction-side short-circuit portion 21 and the number of turns (the number of helical elements) of the outlet-side short-circuit portion 22 may be the same or different from each other.

[0028] When the steam generator connected to the superheated steam generator 100 of the above embodiment is of an induction heating type, it is possible to adopt a configuration including a spirally wound conductor tube as in the above embodiment and a magnetic flux generating mechanism for induction heating the conductor tube. In this case, the conductor tube may be short-circuited in its entire axial direction without dividing the short-circuiting portion as in the above embodiment, or the short-circuiting portion may be divided as in the above embodiment and connected in series by a spiral connecting tube portion.

[0029] In the above embodiment, the superheated steam is generated by heating the steam generated externally, but the superheated steam may be generated by heating water supplied from the outside. In this case, it is possible to adopt a configuration in which the water is heated at the inlet side short-circuit section 21 to generate steam, and the steam is heated at the outlet side short-circuit section 22 to generate superheated steam.

[0030] Furthermore, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications are possible without departing from the spirit of the present invention. [Explanation of symbols]

[0031] 100 Superheated steam generator 2. Conductor tube 21... Introduction side short circuit section 22...Outlet side short circuit section 23... Connection pipe section

Claims

1. A superheated steam generator that generates superheated steam by inductively heating a cylindrical conductor tube wound in a spiral shape using a magnetic flux generating mechanism and heating water or steam flowing through the conductor tube, The conductor tube is an inlet side short circuit portion formed by short circuiting in the axial direction on the inlet side of the water or steam; an outlet-side short-circuit portion formed by short-circuiting in the axial direction on the outlet side of the superheated steam; a spiral connecting pipe portion that connects the inlet side short-circuit portion and the outlet side short-circuit portion and is not short-circuited in the axial direction, said spiral connecting pipe portion having a spiral shape and a spiral shape that is not short-circuited in the axial direction.

2. 2. The superheated steam generator according to claim 1, wherein the inlet side short circuit portion, the outlet side short circuit portion and the connecting pipe portion are integrally formed.

3. A method for manufacturing a conductor tube used in a superheated steam generator, which generates superheated steam by inductively heating a cylindrical conductor tube wound in a spiral shape using a magnetic flux generating mechanism and heating water or steam flowing through the conductor tube, comprising the steps of: A straight conductor tube is bent to form a spiral conductor tube. One end of the spiral conductor tube is short-circuited in the axial direction to form a one-end short-circuit portion; The other end of the spiral conductor tube is short-circuited in the axial direction to form an other-end short-circuit portion; a spiral connection pipe portion is formed without short-circuiting the one end side short-circuit portion and the other end side short-circuit portion in the axial direction.

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