This application claims priority to Korean Patent Application Nos. 10-2016-0077104 filed on Jun. 21, 2016 and 10-2016-0077109 filed on Jun. 21, 2016, the disclosures of each of which are incorporated herein by reference in their entirety.
Exemplary embodiments of the present disclosure relate to a spray nozzle for an attemperator and an attemperator including the same, and more particularly, a cooling water spray nozzle which is provided in equipment such as a steam boiler of a thermal power plant that uses high-temperature steam, and reduces or prevents high-temperature steam from being overheated and controls the temperature of the steam.
Generally, a boiler for power generation is provided with a superheater for generating high-temperature steam needed for a turbine. Steam generated from the superheater is supplied to the turbine through a steam transfer pipe. An attemperator is installed on the steam transfer pipe so as to control the temperature of supplied steam to a temperature required in the turbine.
The attemperator 100 is installed outside the steam transfer pipe 200 through which high-temperature steam is transferred. The attemperator 100 includes a fixed pipe 20 which is installed outside the steam transfer pipe 200 and a spray nozzle 10, which is supported on the fixed pipe 20 and inserted into the steam transfer pipe 200.
The spray nozzle 10 is fixed by the fixed pipe 20 and a first weld 101. The fixed pipe 20, into and to which the spray nozzle 10 is inserted and fixed, is fixed to the outer circumferential surface of the steam transfer pipe 200 by a second weld 102.
In the spray nozzle installed in the above-mentioned manner, vibration is generated by high-temperature and high-pressure steam flowing through the steam transfer pipe, and there is a problem in that a coupling portion of the spray nozzle may be damaged by a resonance phenomenon caused when the frequency of vortex shedding of steam that is generated around the spray nozzle matches the natural frequency of the spray nozzle.
In an effort to overcome this problem, a technique may be employed in which a diaphragm 30 is attached on the outer surface of the spray nozzle. The diaphragm 30 has elasticity and is interposed between the spray nozzle and the fixed pipe, thus mitigating vibrations of the spray nozzle. The diaphragm 30 is fixed to the outer surface of the spray nozzle by a third weld 103.
The spray nozzle having the diaphragm is assembled with the fixed pipe in such a way that the spray nozzle is force-fitted into the fixed pipe, whereby the diaphragm is supported in the spray nozzle and the fixed pipe with sufficient strength. Thereby, the diaphragm increases the natural frequency of the spray nozzle, thus mitigating vibration of the spray nozzle.
However, in the spray nozzle having the above-mentioned shape, there is high probability of thermal deformation in the spray nozzle during a process of attaching the diaphragm to the spray nozzle by welding, and there is also high probability of a defect occurring during the force-fitting operation. Furthermore, there are problems in that it is not easy to separate the conventional spray nozzle from the fixed pipe, and it is difficult to reuse the fixed pipe and the spray nozzle.
An object of the present disclosure is to provide a spray nozzle for an attemperator which has a simple assembly structure and effectively mitigates vibration of the spray nozzle.
Another object of the present disclosure is to provide an attemperator including the spray nozzle having the above-mentioned characteristics.
Other objects and advantages of the present disclosure can be understood by the following description, and become apparent with reference to the embodiments of the present disclosure. Also, it is obvious to those skilled in the art to which the present disclosure pertains that the objects and advantages of the present disclosure can be realized by the apparatus and methods as claimed and combinations thereof.
In accordance with one aspect of the present disclosure, a spray nozzle is installed in an attemperator including a steam transfer pipe through which steam is transferred, and a fixed pipe is fixed on an outer surface of the steam transfer pipe, the spray nozzle being configured to spray cooling water into the steam transfer pipe, wherein the spray nozzle is inserted into and fixed in the fixed pipe, and comprises, on an outer circumferential surface thereof, at least one support protruding toward the fixed pipe, and wherein the support is configured to space the spray nozzle and the fixed pipe apart from each other.
An end of the support and an inner surface of the fixed pipe may be spaced apart from each other.
The support may be disposed inside the outer circumferential surface of the steam transfer pipe.
The support may be formed to protrude in a ring shape from the outer circumferential surface of the spray nozzle.
The spray nozzle may further include: a protrusion formed to protrude from an outer circumferential surface of the support.
The protrusion may include a plurality of protrusions arranged on the outer circumferential surface of the support at positions spaced apart from each other.
The support may include a plurality of supports arranged along the outer circumferential surface of the spray nozzle at positions spaced apart from each other.
A junction between the support part and the spray nozzle may have a round shape.
The support may include a tapered part disposed in a longitudinal direction of the spray nozzle.
A radial end of the tapered part may be disposed radially outside the outer circumferential surface of the steam transfer pipe.
The spray nozzle may further include: a damper provided on the support and mounted so as to be slidable in a radial direction of the support; and an elastic unit interposed between the support and the damper.
In accordance with another aspect of the present disclosure, an attemperator includes: a steam transfer pipe through which steam is transferred; a fixed pipe fixed to an outer surface of the steam transfer pipe; a spray nozzle inserted into the fixed pipe and configured to spray cooling water into the steam transfer pipe; and a nozzle fixing member disposed at a position spaced apart from the fixed pipe and configured to support a free end of the spray nozzle, wherein the spray nozzle comprises, on an outer circumferential surface thereof, at least one support, and the support is configured to space the spray nozzle and the fixed pipe apart from each other.
The nozzle fixing member may be aligned with the fixed pipe, and the free end of the spray nozzle may be inserted into the nozzle fixing member.
A stop protrusion may be provided on an inner surface of the fixed pipe, and a seating part may be provided on the outer circumferential surface of the spray nozzle and supported on a surface of the stop protrusion.
The nozzle fixing member may be inserted into and fixed to the steam transfer pipe.
The nozzle fixing member may be threadedly coupled with the spray nozzle.
A second support may be provided in the nozzle fixing member and formed to protrude toward the spray nozzle.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the claims.
The above and other objects, features and other advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
The following description and drawings illustrate exemplary embodiments of the present disclosure. It will be understood by one of ordinary skill in the art that a variety of equivalents and modifications of the embodiments exist.
Embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.
In the drawings, the width, length, thickness, etc. of each element may have been enlarged for convenience. Furthermore, when it is described that one element is disposed ‘over’ or ‘on’ the other element, one element may be disposed ‘right over’ or ‘right on’ the other element or a third element may be disposed between the two elements. The same reference numbers are used throughout the specification to refer to the same or like parts.
In this regard, an end of the support 40 may be formed such that it is spaced apart from the inner surface of the fixed pipe 20. That is, when an inner diameter of the fixed pipe 20 refers to D2, and a diameter of the support 40 refers to D5, the support 40 may be formed such that D2 is greater than D5. A gap (G) between the end of the support 40 and the inner surface of the fixed pipe 20 refers to (D2−D5)/2, and the effect of reducing vibration to be applied to the spray nozzle may be changed depending on the gap.
Given this, the inventors of the present disclosure have found a change in stress distribution depending on the gap, and the result thereof is shown in
Therefore, it is preferable that the gap be set at approximately 0.2 mm. However, since the spray nozzle for the attemperator has various sizes depending on the purpose of use, it is noted that the gap may be set based on a result of a test for the corresponding size.
Referring to
In this regard, the position of the support 40 may be arbitrarily set, but if the support 40 is disposed outside the outer circumferential surface of the steam transfer pipe 200 with respect to the radial direction, the length between the support 40 and a free end of the spray nozzle 10 is increased, so that force applied to the spray nozzle 10 by the flow of fluid is increased. Thereby, the effect of the support 40 of reducing the stress of the spray nozzle 10 may be reduced. Hence, it is preferable that the support 40 be disposed as close to the center of the steam transfer pipe 200 as possible. Nevertheless, the support 40 preferably does not protrude into the steam transfer pipe 200 and make contact with steam that is transferred through the steam transfer pipe 200.
The support 40 may have a ring shape in which it protrudes from the spray nozzle 10. In detail, as shown in
The support 40 may be modified in various shapes. Referring to
As shown in the drawing, the protrusions 42 may be preferably arranged at intervals of 90°. Alternatively, the protrusions 42 may be irregularly arranged at arbitrary intervals, and an example in which the number of protrusions 42 is greater or less than four may also fall within the bounds of the present disclosure.
In addition, the support 40 may be formed to have a shape shown in
Referring to
Generally, to couple the fixed pipe 20 to the steam transfer pipe 200, a hole corresponding to the inner diameter of the fixed pipe 20 is formed in the outer surface of the steam transfer pipe 200. Thereafter, the fixed pipe 20 is disposed on the hole and fixed to the outer surface of the steam transfer pipe 200 by a method such as welding. Here, it is highly possible that back bead of a weld 102 is formed inside the fixed pipe 20. In the case where the back bead is formed inside the fixed pipe 20, when an assembly process of inserting the spray nozzle 10 into the steam transfer pipe 200 is performed, interference is caused by the back bead. In this case, an additional inner diameter machining process for removing the back bead is required.
However, as shown in
The tapered parts 90 may not only reduce stress concentration but may also provide effect of reducing a bending phenomenon due to vibration of the spray nozzle 10.
In this regard, as shown in
As shown in
Due to the elastic force of the coil spring 52, the damper 50 can be constantly maintained in a state in which it makes contact with the inner surface of the fixed pipe 20. Therefore, even if vibration is caused, the coil spring 52 may compressed and expanded, thus absorbing the vibration. As a result, stress caused by direct contact between the support 40 and the fixed pipe 20 can be mitigated.
Referring to
In this embodiment, a free end 12 of the spray nozzle 10 has a length sufficient to protrude out of the steam transfer pipe 200. A nozzle fixing member 22 is welded to the outer surface of the steam transfer pipe 200 so as to fix the protruded free end 12. The fixed pipe 21 and the nozzle fixing member 22 are disposed on an approximately linear line so that the spray nozzle 10 can be supported on at least two portions.
In detail, as also shown in
Furthermore, an upper end of the spray nozzle 10 is welded to the fixed pipe 21. In this way, since the spray nozzle 10 is fixed at the upper and lower ends thereof, the natural frequency of the spray nozzle 10 is increased to more than three times that of otherwise spray nozzle structures. Therefore, the nozzle may be effectively prevented from being damaged by vibration.
This structure is advantageous for maintenance work. That is, when it is required to separate the spray nozzle 10 from the fixed pipe 21 so as to perform maintenance work later, it can be easily separated therefrom only by removing the weld formed between the spray nozzle 10 and the inner surface of the fixed pipe 21 through a machining process. Because the weld is small compared to that of the conventional art, and a portion to be removed through the machining process is very small, the fixed pipe 21 and the spray nozzle 10 can be reused.
The spray nozzle 10 is configured such that cooling water is discharged through a spray hole to control the temperature of overheated steam. It is preferable that the spray hole is disposed in the central portion of the vertical cross-section of the steam transfer pipe 200. Therefore, the depth to which the spray nozzle 10 is inserted into the steam transfer pipe 200 may be adjusted. For this, as shown in
As shown in
To make the slide movement of the spray nozzle 10 more reliable, as shown in
In addition, an example may be considered, in which the damper 50 introduced in the embodiment of
Although, in all of the above-mentioned examples, the lower end of the spray nozzle 10 has been described as being inserted into and supported by the nozzle fixing member 22, a bolt or the like may be used so as to support the lower end of the spray nozzle 10.
In this regard, the boss 26 may not be formed on the bolt coupling 25. An example may be considered, in which the boss 26 is formed on the spray nozzle 10. That is, as shown in
According to aspects of the present disclosure having the above-mentioned configuration, because a force-fitting method is not required for the operation of fixing a spray nozzle, not only can a process of manufacturing an attemperator be facilitated, but maintenance work can also be easily performed.
In addition, vibration to be applied to the spray nozzle can be easily mitigated, whereby concentration stress applied to a coupling portion or the like of the spray nozzle can be effectively reduced. Consequently, the satisfactory structural strength of the spray nozzle can be secured.
While the present disclosure has been described with respect to the specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the following claims.
Number | Date | Country | Kind |
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10-2016-0077104 | Jun 2016 | KR | national |
10-2016-0077109 | Jun 2016 | KR | national |