TWI791488B - Superheated steam generating device and method of manufacturing conductor pipe used in the device - Google Patents

Abstract

The present invention provides a superheated steam generating device and a method for manufacturing a conductor tube used in the device. By forming a short circuit in the conductor tube, the reactance can be reduced, and the possibility of damage to the junction part and the conductor tube can be reduced. The superheated steam generating device induction-heats the helically wound circular tubular conductor tube through a magnetic flux generating mechanism provided inside or outside the winding portion of the conductor tube, and heats the water flowing through the conductor tube. The steam generates superheated steam, and substantially the entire winding portion of the conductor tube, the opposing surfaces of the adjacent adjacent parts are joined by the joint part, and the thickness of the joint part is equal to or greater than the tube thickness of the conductor tube.

Description

Superheated steam generating device and method of manufacturing conductor pipe used in the device

The present invention relates to a superheated steam generator for generating superheated steam by inductively heating a helically wound conductive tube to heat water vapor flowing in the conductive tube.

Conventionally, in such a fluid heating device, as disclosed in Patent Document 1, there is a method in which, among the helically wound conductor tubes forming the secondary coil, the conductor tubes adjacent to each other in the wound portion are short-circuited to form a short-circuit circuit. , thereby reducing the reactance to increase the heating efficiency of the fluid heating device has been known to the public.

Here, the electrical connection member extending in the axial direction of the spiral is connected to a part of the circumference of the winding portion by welding or the like, or by locally welding and joining conductor tubes adjacent to each other in the winding portion, thereby constituting the of the short circuit.

However, the electrical connection member or welded part as the joint becomes high in temperature due to concentrated short-circuit current, and stress is generated due to deformation due to thermal expansion of the winding part of the conductor tube, thereby causing a problem of damage to the joint part and the conductor tube.

prior art literature

Patent Document 1: Japanese Patent Laid-Open Publication No. 2010-71624

The present invention is made to solve the above-mentioned problems, and the main purpose of the present invention is to reduce reactance by forming a short circuit in a conductor tube, and to reduce the possibility of damage to a junction part and a conductor tube.

That is, the present invention provides a superheated steam generating device that induces heating of the helically wound circular tubular conductor pipe by means of a magnetic flux generating mechanism provided inside or outside the winding portion of the conductor pipe, thereby The water vapor flowing through the conductor tube is heated to generate superheated steam. In the winding part of the conductor tube, the opposing surfaces of the adjacent parts adjacent to each other span substantially the entire circumferential direction, and have a conductive A permanent joint part is joined, and the thickness of the joint part is equal to or greater than the tube thickness of the conductor tube.

According to such a superheated steam generating device, since the adjacent parts adjacent to each other are joined by the joint part across almost the entire circumference of the winding part of the conductor pipe (whole joint), it is possible to avoid thermal expansion caused by partial joint. The stress is concentrated on the junction, which can reduce the possibility of damage to the junction and the conductor tube. In addition, since the conductor pipe is in the shape of a circular pipe and recesses are formed between adjacent parts, the contact area between the joint and the outer peripheral surface of the conductor pipe can be increased by providing the joint in the recess. With this structure, it is possible to reduce the concentration of stress on the junction.

Here, if the distance between the conductor pipe and the junction portion is the same from the induction coil of the magnetic flux generating mechanism, it is desirable that the thickness of the junction portion and the thickness of the conductor pipe be the same value.

However, in the structure in which the conductor pipe is in the shape of a circular pipe and the junction is provided between adjacent portions, the distance between the junction and the induction coil is greater than that of the conductor pipe. If the distance from the induction coil is large, the magnetic coupling becomes weak and the induced voltage becomes low, so the heat generation in this part decreases.

In this way, if a temperature difference occurs between the conductor pipe and the junction, mechanical stress will be generated due to the difference in thermal elongation, which will cause damage such as cracks. Therefore, it is important to make the heat generation as uniform as possible.

By setting the thickness of the junction part to be equal to or greater than the thickness of the conductor tube, the resistance value of the junction part can be reduced, and the amount of heat generated at the junction part can be increased due to an increase in current. As a result, it is possible to equalize the heat generation of the conductor pipe and the junction.

As the joint portion, it may be formed by welding joint. In the case of welding, since the molten metal material easily fills the concave portion between adjacent adjacent portions, the welding work can be facilitated.

In order to easily equalize the amount of heat generated by adjusting the thickness, it is preferable that the electrical resistivity of the material of the joint part is substantially the same as the electrical resistivity of the material of the conductive tube.

In consideration of the workability of engaging the entire winding portion of the conductor pipe, it is preferable that the engaging portion is provided on the outer surface side of the winding portion. In addition, in order to improve magnetic coupling by electromagnetic induction, it is preferable that the magnetic flux generating means is provided both inside and outside of the winding portion of the conductor tube.

Preferably, the engaging portion is accommodated in a recess formed by the adjacent portions adjacent to each other. According to this configuration, it is possible to prevent the radial dimension of the magnetic flux generating means arranged outside or inside the winding portion of the conductor pipe from becoming large.

In addition, the present invention provides a method of manufacturing a conductor pipe used in a superheated steam generating device, which heats the water vapor flowing inside by induction heating to generate superheated steam, and the conductive pipe is wound in a helically wound round tubular Substantially the entire winding portion of the conductor pipe is welded to join the opposing surfaces of the adjacent portions adjacent to each other, and the thickness of the filler (covering) of the welded joint is equal to or greater than the pipe thickness of the conductor pipe.

According to the present invention constituted as described above, since the adjacent parts adjacent to each other are joined by the joint portion across the entire circumferential direction in the winding portion of the conductor tube, a short circuit can be formed in the conductor tube, thereby reducing the reactance, and The possibility of damage to joints and conductor tubes can be reduced.

Hereinafter, one embodiment of the superheated steam generation device 100 of the present invention will be described with reference to the drawings.

As shown in Fig. 1, the superheated steam generating device 100 generates superheated steam exceeding 100°C (200°C-2000°C) by heating water or steam, and the superheated steam generating device 100 has a helically wound A circular tube-shaped conductor tube 2 and a magnetic flux generating mechanism 3 for inductively heating the conductor tube 2 .

The conductor pipe 2 is formed of a metal pipe, has a helically wound winding portion 2x, and is formed at one end of the conductor pipe 2 with an inlet P1 for introducing water or steam, and at the other end with a Outlet P2 from which the generated superheated steam flows out. An external pipe for supplying water or steam to the conductor pipe 2 is connected to the inlet P1, and an external pipe for supplying the generated superheated steam to the use side (for example, a heat treatment chamber) is connected to the outlet P2.

The magnetic flux generating mechanism 3 includes an iron core 31 and an induction coil 32 wound along the iron core 31 . An AC power supply (not shown) is connected to the induction coil 32 and supplies controlled electric power to the induction coil 32 . The induction coil 32 supplied with power from an AC power source serves as a primary coil, and as a result of supplying power to the primary coil, an induced current flows through the conductor tube 2, and the conductor tube 2 becomes a secondary coil.

The induction coil 32 of the present embodiment is disposed coaxially with the winding portion 2x of the conductor tube 2, and the induction coil 32 has: an inner induction coil 32a disposed inside the winding portion 2x; and an outer induction coil 32b disposed outside the winding portion . In this way, the inner induction coil 32a and the outer induction coil 32b arranged inside and outside the winding part 2x can make the magnetic coupling of electromagnetic induction better, and can make it easy to flow an induced current in the conductor tube 2, thereby improving the water vapor flow rate. The heating efficiency (generation efficiency of superheated steam).

In addition, in the present embodiment, as shown in FIG. 2 and FIG. 3 , in the winding portion 2x of the conductor pipe 2, the opposing surfaces of the adjacent portions 20 adjacent to each other span substantially the entire circumferential direction, and have The conductive bonding portion 4 is bonded. That is, the engaging portion 4 is provided across the entire spiral of the winding portion 2x of the conductor pipe 2 .

Specifically, the joint portion 4 is formed by welding (hereinafter also referred to as a joint welded portion). That is, in the winding portion 2x of the conductor pipe 2, the opposing surfaces of the adjacent portions 20 adjacent to each other are entirely joined across the entire helix (see FIG. 2 ). In addition, the electrical resistivity of the material of the junction part 4 is made substantially the same as the electrical resistivity of the material of the conductor pipe 2 . Here, it is preferable that the material of the junction part 4 is the same as that of the conductor tube 2 . In this way, not only the electrical resistivity but also the thermal expansion coefficient can be made the same, whereby the thermal stress generated when the temperature rises can be reduced. In addition, since it is important to maintain a constant distance between a torch and a welding site at a constant feed rate during welding, it is preferable to use an automatic welding machine. In addition, since a bevel exists between the adjacent parts 20 of the conductor pipe 2 from the beginning, it is not necessary to perform beveling.

In addition, as shown in FIG. 3 , the thickness of the joint portion 4 is equal to or greater than the tube thickness of the conductor tube 2 . That is, the thickness of the filler formed by welding as the joint portion 4 is equal to or greater than the pipe thickness of the conductor pipe 2 . The engaging portion 4 is accommodated in the recessed portion 20M formed by the adjacent portions 20 adjacent to each other. More specifically, the engaging portion 4 is formed with a predetermined thickness in a range that can be accommodated in the concave portion 20M from the contact portion 20c of the adjacent portions 20 adjacent to each other or the vicinity thereof. That is, the outer end portion of the conductor tube 2 is located further outside than the outer end portion of the joint portion 4 in a direction perpendicular to the axial direction of the helix (the central axial direction of the winding portion 2 x ).

In FIG. 3 etc., the joint part 4 is provided on both the inner surface side and the outer surface side of the winding part 2x of the conductor pipe 2, but in consideration of the operability of the entire winding part 2x of the conductor pipe 2, it is preferable Note that the engagement portion 4 is provided only on the outer surface side of the winding portion 2x.

As shown in FIG. 4 , although a small gap is formed in operation between the contact portion of the adjacent portion 20 of the winding portion 2x and the filler portion (joint welding portion 4), if the size of the gap is Δ, then It is about 0<Δ<several mm. For example, the conductor pipe 2 used to generate 240 kg of superheated steam at 1200° C. for one hour has a diameter of 48.3 mm and a pipe thickness of 3.7 mm. When the entire winding portion 2x of the conductor tube 2 is welded and the filler thickness is 5 mm, Δ is about 2.5 mm.

If the conductor pipe 2 has a size to allow water vapor to pass through, the distance between the welded portion 4 and the induction coil 32 of the magnetic flux generating mechanism 3 increases when the pipe thickness and filler thickness are equal. Assuming that the wall thickness of the conductor tube 2 is t and the filler thickness of the joint welded portion 4 is T, by setting T>t, the current at the joint welded portion 4 can be increased, thereby increasing the heat generation.

When T=t, the case where the induced voltage of the conductor tube 2 is higher than that of the joint welded portion 4 is marked with a 0 and shown in the following table.

[Table 1]

The amount of heat generation depends not only on the induced voltage but also on the resistance value of the conductive tube 2 and the joint welding portion 4 . That is, the lower the resistance value, the larger the current flowing, and the higher the heat generation.

The case where the circumference of the joint welding portion 4 where the induced voltage is generated is larger than the winding portion 2x of the conductor pipe 2 is set to “0”, and the case where the circumference length of the joint welding portion 4 where the induced voltage is generated is smaller than the winding portion 2x of the conductor pipe 2 Set to "×" and collectively expressed in the table below.

[Table 2]

When the diameter of the conductor pipe 2 is Φ, the maximum value of the filler thickness T at the position "0" in Table 2 falls within the range of (T+Δ)<Φ/2.

<Effects of this embodiment>

According to the superheated steam generating device 100 constituted as described above, since the adjacent parts 20 adjacent to each other in the winding part 2x of the conductor pipe 2 are joined by the joint part 4 across substantially the entire circumferential direction (whole joint), it is possible to Avoiding concentration of stress on the joint portion due to thermal expansion in the case of partial joint can reduce the possibility of damage to the joint portion and the conductor tube. In addition, since the conductor pipe 2 is in the shape of a circular pipe, and the recesses 20M are formed between the adjacent parts 20 adjacent to each other, by providing the junction 4 in the recesses 20M, the outer peripheral surface of the junction 4 and the conductor pipe 2 can be enlarged. the contact area. This configuration also reduces the concentration of stress on the junction.

Since the thickness T of the junction part 4 is equal to or greater than the thickness t of the conductor tube 2, the resistance value of the junction part 4 can be reduced, and the heat generation can be increased by increasing the current.

In addition, since the joint portion 4 is formed by welding, the concave portion 20M between the adjacent adjacent portions 20 is easily filled with molten metal material, so the welding work can be facilitated.

＜Other Modified Embodiments＞

In addition, this invention is not limited to each said embodiment.

For example, in the above-described embodiment, the joint portion 4 is formed by joint welding, but it may also be formed by brazing. In addition, a connecting member provided separately from the conductor tube may be wound along the adjacent portion of the winding portion, and the connecting member may be connected to the conductor tube 2 by welding or soldering, thereby connecting the connecting member to the conductor tube 2. as joint 4.

In addition, this invention is not limited to the said embodiment, Of course, various deformation|transformation is possible in the range which does not deviate from the summary of this invention.

The technical features described in the various embodiments (examples) of the present invention can be combined with each other to form new technical solutions.

2‧‧‧conductor tube 2x‧‧‧winding part 3‧‧‧magnetic flux generating mechanism 4‧‧‧junction part, joint welding part 20‧‧‧adjacent part 20c‧‧‧contact part 20M‧‧‧recessed part 31‧ ‧‧Core 32‧‧‧Induction coil 32a‧‧‧Inner induction coil 32b‧‧‧Outer induction coil 100‧‧‧Superheated steam generating device

FIG. 1 is a cross-sectional view schematically showing the structure of a superheated steam generator according to the present embodiment. Fig. 2 is a partially enlarged cross-sectional view showing a winding portion of the conductor pipe according to the embodiment. Fig. 3 is a schematic view showing a welded portion on the outer surface side of the conductor pipe according to the embodiment. Fig. 4 is a schematic diagram showing the positional relationship between the conductor pipe and the induction coil in the embodiment.

2‧‧‧conductor tube

2x‧‧‧winding part

4‧‧‧joint part, joint welding part

20‧‧‧adjacent part

20c‧‧‧Contact parts

20M‧‧‧Concave

Claims (5)

A superheated steam generating device, characterized in that the superheated steam generating device applies a helically wound A circular tubular conductor tube is heated by induction, thereby heating the water vapor flowing through the conductor tube to generate superheated water vapor; in the winding part of the conductor tube, an adjacent part adjacent to each other, Across the whole of the circumferential direction, it is joined by a joint part having conductivity; the joint part is accommodated in a recess formed by the adjacent parts adjacent to each other, and the induction coil of the magnetic flux generating mechanism The distance from the junction part is greater than the distance from the induction coil of the magnetic flux generating mechanism to the conductor pipe; and a thickness of the junction part is more than a pipe thickness of the conductor pipe. The superheated steam generator according to claim 1, wherein the joint is formed by welding. The superheated steam generating device according to claim 1, wherein a resistivity of a material of the junction part is the same as a resistivity of a material of the conductive tube. The superheated steam generating device according to claim 1, wherein: the magnetic flux generating mechanism is provided on both inside and outside of the winding portion of the conductor tube; and the joint portion is provided on the winding portion. An outer surface side of the part. A method for manufacturing a conductor tube, wherein the conductor tube is used in a superheated steam generating device, and is heated by induction by a magnetic flux generating mechanism having an induction coil, thereby heating the water vapor flowing inside to generate superheat water vapor; In the whole of a winding portion of a circular tubular conductor pipe wound helically, the opposing surfaces of adjacent portions adjacent to each other are welded and joined by a joint portion; the joint portion is accommodated by the In a recess formed by the adjacent parts adjacent to each other, the distance between the induction coil of the magnetic flux generating mechanism and the joint part is greater than the distance between the induction coil of the magnetic flux generating mechanism and the conductor tube; And, the thickness of the joint portion is set to be equal to or greater than one pipe thickness of the conductor pipe.

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