JP2007024456A - Temperature reducing pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature reducing pipe capable of improving strength reliability and durability by preventing excessive local stress concentration. <P>SOLUTION: The temperature reducing pipe 10 for cooling high temperature vapor circulating inside by cooling water sprayed from a spray nozzle 20 inserted from a radial direction consists of a main pipe 1 as a pressure-proof part, a sleeve 2 for protecting the main pipe 1 from thermal shock generated by rapid temperature reduction by the cooling water sprayed from the spray nozzle 20, a fixing ring 3, provided between the sleeve 2 and the main pipe 1 with a clearance between the ring and the sleeve 2, having a long hole 6 extending in the direction of vapor flow in a pipe wall and a pin 4, fixed by the sleeve 2, of which tip end part protruding from an outer circumference surface of the sleeve 2 is positioned in the long hole 6 of the fixing ring 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a temperature reducing pipe that cools high-temperature steam flowing through the inside by cooling water sprayed from a spray nozzle.

  The temperature reducing pipe is installed in a system that lowers the temperature of steam, hot water, etc. flowing in the pipe according to the application. As a method for reducing the temperature of steam or hot water flowing through the pipe, in addition to a method for reducing the temperature of hot water by mixing with cooling water, a temperature reduction as described in JP-A-2004-218985 A typical method is to spray the cooling water from the spray nozzle inserted in the pipe and reduce the temperature of the steam by the heat of vaporization of the water. In the temperature reduction method in which the cooling water is sprayed on the steam, the temperature reduction width is particularly large, and a thermal shock resulting from a rapid temperature drop may occur in the temperature reduction pipe.

JP 2004-218985 A

  Here, in this type of temperature reducing pipe, a sleeve for protecting the mother pipe from thermal shock is generally attached to the inner peripheral surface of the mother pipe forming a part of the steam cooling system. Usually, the sleeve is attached to a fixing ring interposed between the inner peripheral surface of the mother pipe. The end of the sleeve on the upstream side in the steam flow direction is fixed to the inner peripheral surface of the fixing ring by welding. At this time, a gap is required between the fixing ring and the mother pipe or sleeve for manufacturing. When a gap is provided between the fixing ring and the mother pipe, the fixing ring is often fixed by welding the upstream side to the inner wall surface of the mother pipe and the downstream side to the outer wall surface of the sleeve. In contrast, when a gap is provided between the fixing ring and the sleeve, the upstream side and the downstream side of the fixing ring are often fixed to the inner peripheral surface of the mother pipe. Because of such production problems, it is usual that either the sleeve or the fixing ring is fixed only on the upstream side with a gap on the outer peripheral side thereof.

  In such a general temperature reducing tube, when high temperature steam flows inside the temperature reducing tube, the metal temperature of the inner wall surface of the temperature reducing tube is higher than the outer wall surface on the mother tube side, resulting in a thermal expansion difference in the radial direction. . Then, under the influence of this thermal expansion, thermal stress concentrates on the welded portion upstream of the sleeve or fixing ring having a gap on the outer peripheral side. This was a factor that shortened the life of the hot tubes.

  An object of the present invention is to provide a temperature reducing tube that can prevent excessive stress concentration locally and improve strength reliability and durability.

  (1) In order to achieve the above object, the present invention provides a temperature reducing pipe that cools high-temperature steam flowing through the inside by cooling water sprayed from a spray nozzle inserted in a radial direction, The sleeve is inserted into the inner peripheral portion of the mother pipe and protects the mother pipe from thermal shock generated by the rapid temperature reduction caused by the cooling water sprayed by the spray nozzle, and has a gap between the sleeve and the sleeve. A fixing ring which is disposed between the sleeve and the mother pipe and has a long hole in the pipe wall extending in the flow direction of the steam; and a tip which is fixed to the sleeve and protrudes from the outer peripheral surface of the sleeve. And a pin located in the elongated hole.

  (2) In the above (1), preferably, when an excessive load is applied to the pin, the pin breaks preferentially to surrounding members.

  (3) In the above (2), preferably, the movement range of the sleeve when the pin is broken is limited so that the elongated hole of the fixing ring is not exposed to the steam flow path even if the pin is broken. A stopper is provided.

  (4) In the above (1), preferably, a stopper for limiting a moving range of the fixing ring in the steam flow direction is provided on the upstream side and the downstream side of the fixing ring.

  (5) In order to achieve the above object, the present invention also provides a main pipe which is a pressure-resistant part in a temperature reducing pipe which cools high-temperature steam flowing through the inside by cooling water sprayed from a spray nozzle inserted from the radial direction. And a sleeve that is inserted into the inner peripheral portion of the mother pipe and protects the mother pipe from a thermal shock generated by a sudden temperature reduction by the cooling water sprayed by the spray nozzle, and between the sleeve and the mother pipe A fixing ring that is disposed and has a long hole in the tube wall extending in the steam flow direction; and a pin that is fixed to the mother pipe and that protrudes from the inner peripheral surface of the mother pipe and is located in the long hole of the fixing ring It is provided with.

  According to the present invention, thermal expansion in the radial direction and the steam flow direction of the sleeve can be absorbed, so that excessive stress concentration can be prevented from occurring and strength reliability and durability can be improved. .

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view showing the internal structure of the temperature reducing tube according to the first embodiment, and FIG. 2 is a cross-sectional view taken along the line AA of FIG.
The temperature reducing pipe 10 shown in FIG.1 and FIG.2 is provided in piping which distribute | circulates the vapor | steam generate | occur | produced from the boiler etc. in business or industrial power generation equipment, for example, and water (low-temperature fluid) is supplied to steam (high-temperature fluid) Sprays and injects to cool the steam and control the steam temperature. The temperature reducing pipe 10 cools high-temperature steam flowing through the inside by cooling water sprayed from at least one spray nozzle 20 of a temperature reducer inserted from the radial direction. In the present embodiment, only the upstream portion of the temperature reducing pipe in the steam flow direction (arrow 7) is shown, and the downstream portion of the spray nozzle 20 is not shown. In the following description, the upstream side in the steam flow direction is simply referred to as the upstream side, and the downstream side in the steam flow direction is simply referred to as the downstream side.

  The temperature reducing pipe 10 shown in the figure includes a mother pipe 1 that is a pressure-resistant portion that forms part of the steam pipe, and a sleeve 2 that protects the mother pipe 1 from thermal shock that occurs due to sudden temperature reduction caused by cooling water sprayed by the spray nozzle 20. And a fixing ring 3 for slidably supporting the sleeve 2 with respect to the mother pipe 1 and a pin 4 for locking the sleeve 2 to the fixing ring 3.

  The fixing ring 3 is inserted into the inner peripheral part of the mother pipe 1, and the upstream and downstream ends are fixed to the inner peripheral part of the mother pipe 1 by fillet welding, and the mother pipe is connected via the fillet weld part 5. 1 is supported on the inner peripheral surface. An elongated hole 6 extending in the steam flow direction is provided in the tube wall of the fixing ring 3. In the present embodiment, the case where the elongated holes 6 are provided at two locations at equal intervals in the circumferential direction of the fixing ring 3 is illustrated, but the elongated holes 6 may be provided at only one location or at three or more locations. However, when a plurality of locations are provided, it is not always necessary to provide them at regular intervals as illustrated.

  The sleeve 2 is disposed on the inner peripheral side of the fixing ring 3, and a slight gap is interposed between the sleeve 2 and the inner peripheral surface of the fixing ring 3. On the tube wall of the sleeve 2, the pin 4 is arranged along the radial direction of the temperature reducing tube 10 so that the position corresponds to the elongated hole 6 of the fixing ring 3. The pin 4 is fixed by being fillet welded to the inner peripheral surface of the sleeve 2 in a state of penetrating the tube wall of the sleeve 2 in the vicinity of the upstream end portion of the sleeve 2. The pin 4 is supported on the inner peripheral surface of the sleeve 2 through the fillet weld portion 5. The distal end portion of each pin 4 on the radially outer side of the temperature reducing tube protrudes from the outer peripheral surface of the sleeve 2 and is located in the corresponding long hole 6 of the fixing ring 3.

  With such a configuration, the sleeve 2 is engaged with the mother pipe 1 and the fixing ring 3 so as to be slidable in the steam flow direction by a stroke that allows the pin 4 to move within the long hole 6 of the fixing ring 3.

  Further, the pin 4 may be a general cylindrical one, but is preferably configured to break with priority over surrounding members when an excessive load is applied. For example, it may be configured to preferentially break at the groove portion when an excessive load is applied, for example, by attaching a groove to the portion of the pin 4 protruding from the sleeve 2. Moreover, if a bolt, a screw, or the like is used as the pin 4, when an excessive load is applied, the pin 4 breaks preferentially at the valley of the screw, which is easier in production.

  When all the pins 4 are broken due to an excessive load, the sleeve 2 tends to move further downstream from the position shown in FIGS. Although not particularly shown in the present embodiment, a stopper is provided on the inner peripheral surface of the mother pipe 1, and the movement range of the sleeve 2 when the pin 4 is broken is restricted by the stopper. At this time, the stopper is positioned slightly downstream from the downstream end portion of the sleeve 2 in a state where the pin 4 is in contact with the downstream end of the elongated hole 6 as shown in FIGS. The distance between the stopper and the downstream end of the sleeve 2 is the distance between the upstream end of the sleeve and the upstream end of the slot 6 when the sleeve 2 is in the state shown in FIGS. x or less is set.

  That is, before the pin 4 breaks, of course, even if the pin 4 breaks, the upstream end of the sleeve 2 is located at the same position as the upstream end of the long hole 6 or at the upstream side, and is always long. The outer peripheral surface of the sleeve 2 wraps in the hole 6 so that the long hole 6 is not exposed to the steam flow path.

FIG. 3 is a cross-sectional view showing an internal structure of one configuration example of a general temperature reducing tube, and FIG. 4 is a cross-sectional view showing an internal structure of another configuration example of the general temperature reducing tube.
In the temperature reducing pipe shown in FIGS. 3 and 3, the mother pipe 1, the fixing ring 3 ′, and the sleeve 2 ′ are joined by fillet welding. However, it is difficult to produce such that the mother pipe 1, the fixing ring 3 ', and the sleeve 2' are in contact with each other without any gap. Therefore, in FIG. 3, a gap necessary for manufacturing is provided between the mother pipe 1 and the fixing ring 3 ′ and in FIG. 4 between the fixing ring 3 ′ and the sleeve 2 ′.

  Therefore, when the sleeve 2 'expands in the radial direction in response to the heat of the circulating steam, the mother pipe 1 and the fixing ring 3' in FIG. 3 and the fixing ring 3 'and the sleeve 2' in surface contact in FIG. 3, the thermal stress is applied to the fillet weld 5 in which the mother pipe 1 and the fixing ring 3 ′ are joined in FIG. 3, and in FIG. 4 the fillet weld 5 in which the fixing ring 3 ′ and the sleeve 2 ′ are joined. Concentrate. Thermal stress is inevitably generated when a temperature reducing tube is used, and the greater the stress concentration, the easier it is for cracks to occur in the welded part, leading to a shortened life of the temperature reducing tube.

  The sleeve 2 'also thermally expands in the axial direction (steam flow direction) when the temperature reducing tube is used. However, due to some factor on the downstream side, the mother tube and the sleeve are caught and the thermal expansion is restricted. As a result, thermal stress concentrates on the fillet welded part 5, which also causes the life of the temperature reducing tube to be shortened. Further, when the welded portion connecting the mother pipe 1 and the fixing ring 3 ′ is broken, a crack develops in the pipe wall of the mother pipe 1 depending on the progress of the crack, and steam leaks from the crack and causes the plant to stop. There is also a fear. In addition, when a crack occurs in each welded part, depending on the progress of the crack, the fixing ring 3 ′ and the sleeve 2 ′ are damaged, and a piece of the damaged part is caused to flow downstream along with the steam flow. May flow into the equipment and damage these devices.

  On the other hand, in this embodiment, the sleeve 2 and the fixing ring 3 are engaged by the pin 4. That is, since the sleeve 2 and the fixing ring 3 are not fixed by welding or the like, even if the sleeve 2 is expanded in the radial direction by thermal expansion, the fillet weld 5 Thermal stress does not concentrate excessively. Even if the sleeve 2 does not contact the fixing ring 3 even if it thermally expands in the radial direction, the sleeve 2 is subjected to the thermal expansion of the entire inner peripheral surface of the fixing ring 3, so that the thermal stress can be relaxed. Thereby, it can prevent that excessive stress concentration generate | occur | produces locally, and can improve intensity | strength reliability and durability.

  Further, regarding thermal expansion in the flow direction of the sleeve 2, since the pin 4 is engaged with the elongated hole 6 provided in the fixing ring 3, the sleeve 2 can freely slide along the flow direction to some extent. The concentration of thermal stress on the welded portion by restraining the thermal elongation in the axial direction, which is a problem in FIGS. 3 and 4, can be alleviated.

  Further, as described above, in the present embodiment, when the thermal stress is excessively applied, the pin 4 is broken in preference to the surrounding members, so that the mother pipe 1 is cracked. Steam does not leak outside. Even if the pin 4 breaks, the stopper 2 provided in the mother pipe 1 limits the movement range of the sleeve 2 so that the long hole 6 is always covered with the sleeve 2 and is not exposed to the steam flow path. The broken pin 4 can be fastened in the space covered by the inner wall surface of the long hole 6, the inner peripheral surface of the mother pipe 1, and the outer peripheral surface of the sleeve 2. Thereby, it is possible to prevent the broken piece from being caused to flow downstream along with the steam flow and flow into the downstream equipment and damage the equipment.

FIG. 5 is a cross-sectional view showing the internal structure of the temperature reducing tube according to the second embodiment, and FIG. 6 is a cross-sectional view taken along the line BB of FIG. In these drawings, parts similar to those in FIG. 1 or FIG.
As shown in FIGS. 5 and 6, the present embodiment is different from the first embodiment in that the mother pipe 1 and the fixing ring 3 are fixed using a stopper 8 for setting the fixing ring position instead of welding. It is a point to do. In the present embodiment, the mother pipe 1 and the fixing ring 3, and the fixing ring 3 and the sleeve 2 are not fixed by direct welding or the like, but have a gap therebetween.

  The stopper 8 is provided in at least one place in the circumferential direction of the inner peripheral surface of the mother pipe 1 and is disposed on the upstream side and the downstream side of the fixing ring 3 with a slight gap. It is joined to the inner peripheral surface. Thereby, the movement range of the fixing ring 3 in the flow direction is limited.

  At this time, a notch portion 9 is provided in at least one of the upstream end portion and the downstream end portion of the fixing ring 3 (upstream end portion in the present embodiment), and the notch portion 9 corresponds to the notch portion 9. The stopper 8 is opposed to the flow direction. Although the notch 9 is installed upstream of the fixing ring 3 in FIG. 6, it may be installed downstream of the fixing ring 3. The depth dimension (the dimension in the flow direction) of the notch 9 is such that the notch 9 when the fixing ring 3 abuts on the stopper 8 on the downstream side and the stopper 8 facing the notch 9 in the flow direction. It is larger than the gap dimension, and the corresponding stopper 8 always faces the notch 9. Thereby, the range of movement of the fixing ring 3 in the circumferential direction is limited to within the difference in the circumferential width of the notch 9 and the stopper 8.

Further, the height dimension (dimension in the temperature reducing pipe radial direction) z of the stopper 8 is set smaller than the thickness (dimension in the temperature reducing pipe radial direction) y of the fixing ring 3. As a result, when the sleeve 2 expands in the radial direction due to thermal expansion (when the sleeve 2 moves downward in FIG. 6), the sleeve 2 does not contact the stopper 8 but comes into surface contact only with the fixing ring 3. It is configured.
Other configurations are the same as those of the first embodiment.

  Also in the present embodiment, the thermal expansion in the radial direction of the sleeve 2 can be absorbed by the radial gap between the sleeve 2, the fixing ring 3, and the mother pipe 1, and the steam flow of the sleeve 2 is supported by the support structure by the long hole 6. Since the thermal expansion in the direction can also be absorbed, the same effect as that of the first embodiment can be obtained. Of course, as in the first embodiment, when an excessive load is generated, the pin 4 is broken preferentially, so that it is possible to prevent the surrounding members from being damaged. Therefore, it is possible to prevent the equipment on the downstream side of the piping from being damaged.

  In addition, since the sleeve 2, the fixing ring 3, and the mother pipe 1 are not fixed to each other in this embodiment, local stress concentration does not occur in each pipe, and the mother pipe 1 and the stopper 8 are joined. Since the thermal stress of the meat weld can also be relaxed, the durability of the temperature reducing tube can be further improved. Further, since the gap is provided between the sleeve 2, the fixing ring 3, and the mother pipe 1, it is possible to more flexibly cope with the thermal expansion of the sleeve 2 in the radial direction.

  In the above description, the case where the pin 4 is engaged with the fixing ring 3 from the radially inner peripheral side has been described as an example. However, the pin 4 may be engaged from the outer peripheral side, that is, the mother pipe 1 side. it can. That is, although not shown in particular, for example, the sleeve 2 and the fixing ring 3 are fixed by welding, and the fixing ring 3 and the mother pipe 1 are not welded but a gap is interposed therebetween, and is fixed over the pipe wall of the mother pipe 1. It can be considered that the pin 4 faces the long hole 6 of the ring 3. Further, when the sleeve 2, the fixing ring 3 and the mother pipe 1 are not fixed to each other as in the second embodiment, the pin 4 is simply exposed to the long hole 6 of the fixing ring 3 over the pipe wall of the mother pipe 1. What is necessary is just composition.

  Moreover, although the case where the both ends of the long hole 6 were formed in circular arc shape in each figure was illustrated above, the shape of the long hole 6 is not specifically limited. In short, it is sufficient if the engagement with the pin 4 and the sliding state are good. Moreover, although the case where it welded to the mother pipe 1 on both the upstream side and the downstream side of the fixing ring 3 was given as an example in FIGS. 1 and 2, only one of them may be welded. In addition, the spray nozzle 20 may be connected to the mother pipe 1 and may be any type of device as long as it satisfies the temperature reduction function, and the connection direction and the number of installations are within the range satisfying the function. Not limited.

It is sectional drawing showing the internal structure of the temperature reducing tube which concerns on 1st Embodiment. It is sectional drawing by the AA cross section in FIG. It is sectional drawing showing the internal structure of one structural example of a general temperature-reduction tube. It is sectional drawing showing the internal structure of the other structural example of a general temperature-reduction tube. It is sectional drawing showing the internal structure of the temperature reducing tube which concerns on 2nd Embodiment. It is sectional drawing by the BB cross section in FIG.

Explanation of symbols

1 Mother tube 2 Sleeve 3 Fixing ring 4 Pin 6 Elongated hole 8 Stopper 10 Temperature reducing tube 20 Spray nozzle

Claims (5)

In the temperature reducing pipe that cools the high-temperature steam flowing through the inside by the cooling water sprayed from the spray nozzle inserted from the radial direction,
A mother pipe which is a pressure-resistant part;
A sleeve that is inserted into the inner periphery of the mother pipe and that protects the mother pipe from thermal shock caused by rapid temperature reduction due to cooling water sprayed by the spray nozzle;
A fixing ring having a gap between the sleeve and the sleeve and the mother pipe, and having a long hole in the pipe wall extending in the steam flow direction;
A temperature reducing tube, comprising: a pin fixed to the sleeve and having a distal end protruding from an outer peripheral surface of the sleeve and positioned in an elongated hole of the fixing ring.   2. The temperature reducing tube according to claim 1, wherein the pin breaks preferentially to surrounding members when an excessive load is applied.   The temperature reducing pipe according to claim 2, wherein a stopper is provided to limit a moving range of the sleeve when the pin is broken so that the elongated hole of the fixing ring is not exposed to the steam flow path even if the pin is broken. A temperature reducing tube characterized by   2. The temperature reducing pipe according to claim 1, wherein stoppers for limiting a moving range of the fixing ring in a steam flow direction are provided on an upstream side and a downstream side of the fixing ring. In the temperature reducing pipe that cools the high-temperature steam flowing through the inside by the cooling water sprayed from the spray nozzle inserted from the radial direction,
A mother pipe which is a pressure-resistant part;
A sleeve that is inserted into the inner periphery of the mother pipe and that protects the mother pipe from thermal shock caused by rapid temperature reduction due to cooling water sprayed by the spray nozzle;
A fixing ring disposed between the sleeve and the mother pipe and having a long hole in the pipe wall extending in the steam flow direction;
A temperature reducing pipe, comprising: a pin fixed to the mother pipe and having a tip portion protruding from an inner peripheral surface of the mother pipe located in a long hole of the fixing ring.

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