JP2015114165A - Tube inner surface observation fixture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tube inner surface observation fixture which can be used when an inner surface of a large-diameter tube is observed by inserting a fiber scope into inside the large-diameter tube and which enables an observation object located at a high position to be easily observed.SOLUTION: There is provided a tube inner surface observation fixture 10 which supports a tip observation part Vt of a fiber scope SF when the fiber scope SF is inserted into inside a tube from an inspection nozzle 6 to observe the tube inside. The fixture 10 includes: a guide tube 11 in which an inlet opening is formed at one end part; and a fixture body 30 which is connected to the guide tube 11 via a universal joint 20 and is inserted into inside the tube from the inspection nozzle 6. The fixture body 30 includes: an opening/closing mechanism for selectively switching between an inserted condition in which a plurality of leg parts 31 are closed so as to have a smaller diameter than the inspection nozzle 6 and an observing condition in which the leg parts 31 are opened and the tip end parts 31a thereof come in close contact with a tube inner wall surface 1a; and a support cylinder 50 fitted to the leg part 31. A guide passage of the fiber scope FS is formed which communicates with the support cylinder 50 from the inlet opening of the guide tube 11.

Description

  The present invention relates to a tube inner surface observation jig used for observing a tube inner surface using a fiberscope, and more particularly to a tube inner surface observation jig suitable for observing the inner surface of a large diameter pipe.

Conventionally, for example, land boilers are provided with an overheat reducer that adjusts the temperature by blowing steam for temperature adjustment to the overheated steam that flows in the superheated steam pipe.
For example, the superheat reducer H shown in FIG. 6 has a double pipe structure in which a protective cylinder 4 is attached to the inside of the superheated steam pipe 1 using a plurality of setting bolts 2 and presser bolts 3. A gap 5 is formed between the wall surface 1 a and the outer wall surface of the protective cylinder 4. Note that the general superheated steam pipe 1 is a large diameter pipe having a diameter of 800 mm or more, and the superheat reducer H is used by being connected to both ends of the pipe through which superheated steam flows.

  One set bolt 2 is provided at an equal pitch of 90 degrees in the circumferential direction in the vicinity of one end portion of the protective cylinder 4, and all of them pass through the superheated steam pipe 1 and the protective cylinder 4 from the outside of the superheated steam pipe 1. It is screwed. The other presser bolts 3 are provided at an equal pitch of 90 degrees in the circumferential direction, penetrate the superheated steam pipe 1 from the outside of the superheated steam pipe 1 and come into contact with the outer wall surface of the protective cylinder 4. The presser bolt 3 is provided in the vicinity of the center portion and the other end portion of the protective cylinder 4.

In such an overheat reducer H, when a fatigue crack occurs in the setting bolt 2 or the presser bolt 3, the protective cylinder 4 cannot be fixed at a predetermined position and may be scattered by the flow of the superheated steam. Is done. The setting bolt 2 and the presser bolt 3 are installed in a gap 5 formed between the superheated steam pipe 1 and the protective cylinder 4, and therefore cannot be confirmed visually.
For this reason, in the conventional tube inner surface observation, it is conceivable to open the inspection nozzle 6 serving as an inspection hole provided in the superheated steam pipe 1 and insert the fiberscope FS from the inspection nozzle 6 to observe the presence or absence of abnormality.

  In Patent Document 1 below, when detecting corrosion inside a steel pipe such as a horizontal member or diagonal member of a steel tower, an image pickup means that can hold a detection head of an image pickup means that is inserted into the steel pipe and moves at the center position of the steel pipe. A holder is disclosed.

JP-A-9-229868

By the way, the superheated steam pipe 1 described above is a large-diameter pipe having a diameter of 800 mm or more. For this reason, in the illustrated configuration example, it is possible to observe all four setting bolts 2 located near the inspection nozzle 6 with the fiber scope FS.
However, for the presser bolt 3 located far from the inspection nozzle 6, the fiberscope FS is bent downward due to its own weight, so that the tip observation part Vt is located below the inner wall surface (bottom side) of the protective cylinder 4. Become. For this reason, the presser bolt 3 inside the pipe at a position far from the tip observation portion Vt cannot bring the tip observation portion Vt close to the desired observation position, and therefore it is difficult to sufficiently perform the necessary observation. Is in the situation.

As described above, inside the large-diameter pipe such as the superheated steam pipe 1, the fiberscope FS is easily bent, so that the tip observation part Vt is located at a position away from the insertion port (distant upward from the pipe bottom). Thus, it is not possible to bring the object close to the observation object at the position). Therefore, a countermeasure that makes it easy to observe such an observation object is desired.
The present invention has been made to solve the above-mentioned problems, and the object of the present invention is to be used when observing with a fiberscope inserted into a large-diameter pipe, and to easily observe an observation object at a high place. It is another object of the present invention to provide a tube inner surface observation jig that enables observation.

In order to solve the above problems, the present invention employs the following means.
A pipe inner surface observation jig according to the present invention is a pipe inner surface observation jig that supports a tip observation part when a fiberscope is inserted from an inspection hole provided in a large-diameter pipe to observe the inside of the pipe. A guide tube that forms an entrance opening of the fiberscope at one end that is the outside of the diameter pipe, and a jig body that is connected to the guide tube via a universal joint and is inserted into the pipe from the inspection hole. An opening / closing mechanism for selectively switching between an insertion state in which a plurality of legs are closed so that the jig main body has a smaller diameter than the inspection hole and an observation state in which the legs are opened and the tip is closely attached to the inner wall surface of the tube And a support tube attached in the vicinity of the distal end portion of the leg portion and facing the axial direction of the large-diameter pipe in the observation state, from the inlet opening of the guide tube, the universal joint, the jig body, and Is characterized in that said fiberscope guide passage communicating with said support tube through the Kiashi portion is formed.

  According to such a tube inner surface observation jig, the jig body with the legs closed is inserted into the large-diameter pipe from the inspection hole, and the pipe is turned about 90 degrees at the universal joint. After turning in the axial direction, the leg is opened by an opening / closing mechanism to bring it into an observation state. In this observation state, since the leg portion opens outward and comes into close contact with the inner wall surface of the pipe, the jig body is fixed to the center of the large-diameter pipe by the alignment function. At this time, the support tube attached to one of the legs is in the state of facing the pipe axis direction in the vicinity of the inner wall surface inside the pipe. Therefore, the fiberscope inserted from the inlet opening of the guide tube is a universal joint, jig. It passes through a guide passage communicating with the support cylinder via the main body and the leg, and reaches the opening at the tip of the support cylinder. And if you fix the jig body so that the support tube is located on the upper end side inside the tube, the support tube will support the fiberscope so that it will not be bent by its own weight, so the tip observation part is the height of the large diameter pipe (upper part) It is possible to easily observe the observation object in the area.

  In the above tube inner surface observation jig, the jig main body is fixedly supported through a fixed portion serving as a base by providing the guide passage therein, and the vicinity of the central portion of the fixed portion, and on the outer peripheral surface. A guide tube with rack in which a rack gear is formed, a drive unit slidably provided along the guide tube with rack, and a pinion gear that is rotated by a drive source fixedly supported by the drive unit and meshes with the rack gear And three leg portions that are supported by the fixed portion so that one end thereof is swingable and are equally arranged in the circumferential direction, and link members that respectively connect the drive portion and the leg portion. It is preferable to provide a tripod structure opening / closing mechanism that can be opened and closed by remote operation.

  In such an open / close mechanism with a tripod structure, when the drive source is remotely operated in the inserted state and the pinion gear is rotated, the drive unit slides in the direction approaching the fixed unit along the guide tube with the rack by the rack and pinion mechanism. Therefore, it is possible to open the three leg portions supported by the fixed portion so as to be swingable through the link member connected to the drive portion.

In the above-described tube inner surface observation jig, the support cylinder preferably has a multi-stage nesting structure provided with an expansion / contraction mechanism that can be expanded and contracted in the axial direction by remote control, thereby extending the support cylinder. Observation at a position away from the inspection hole becomes possible.
In this case, the expansion / contraction mechanism includes a rack gear fixedly supported at the tip of the support cylinder and a pinion gear that is rotated by a driving source fixedly supported on the outer peripheral surface of the support cylinder which is the outermost side in the contracted state. The rack & pinion mechanism comprised can be illustrated. In addition, in order to orient the support cylinder in the axial direction of the large-diameter pipe, a support cylinder link member pin-coupled to the support cylinder is provided, and the other end of the support cylinder link member is between the drive unit and the leg part. What is necessary is just to engage with the guide groove provided in the link member which connects.

  In the above-mentioned tube inner surface observation jig, it is preferable to attach a sliding member to the tip of the leg portion, whereby the jig body can be easily rotated and moved to change the observation position in the circumferential direction. In this case, examples of suitable sliding members include cover members and rollers made of Teflon (registered trademark).

  The above-mentioned tube inner surface observation jig is used when inserting and observing a fiberscope inside a large-diameter pipe, so that the tip observation part of the fiberscope that is bent by its own weight is observed at a high place away from the bottom of the pipe Accordingly, the object to be observed on the upper surface side inside the pipe away from the insertion position can be easily observed.

It is a figure which shows one Embodiment of the pipe inner surface observation jig | tool which concerns on this invention, (a) is the state which is observing the pipe inner surface upper part, (b) is in the state which shrunk the expansion-contraction mechanism of the support cylinder of (a). is there. It is the figure (right side view) which looked at the pipe inner surface observation jig shown to Fig.1 (a) from the pipe-axis direction. FIG. 1 (a) shows a state in which the jig body of the tube inner surface observation jig is inserted into the pipe through the inspection hole (inspection nozzle) and turned, and before the tripod is opened. . The tube inner surface observation jig in the state shown in FIG. 3 shows a state before the tripod portion is opened and the stretchable portion is extended. It is sectional drawing which shows the structural example of a universal coupling part. It is a figure which shows the example of the conventional pipe inner surface observation, (a) is the state which is observing the pipe inner surface upper part, (b) is AA sectional drawing of (a), (c) is B- of (a). It is B sectional drawing.

Hereinafter, one embodiment of a tube inner surface observation jig concerning the present invention is described based on a drawing.
The pipe inner surface observation jig 10 according to the embodiment shown in FIGS. 1 to 5 is applied to, for example, an overheat reducer H provided in a land boiler as an example of a large-diameter pipe. The superheat reducer H has a double-pipe structure of a large-diameter superheated steam pipe 1 and a protective cylinder 4 provided so that temperature-injecting steam injection does not affect the superheated steam pipe 1. In the figure, reference numeral 2 is a setting bolt, 3 is a presser bolt, and 5 is a gap formed between the superheated steam pipe 1 and the protective cylinder 4.

  The pipe inner surface observation jig 10 is observed with a fiberscope FS in which a setting bolt 2 and a presser bolt 3 for attaching the protective cylinder 4 to the superheated steam pipe 1 of the superheat reducer H are inserted from an inspection nozzle 6 serving as an inspection hole, cracks, etc. Used to check for the presence or absence of In particular, the tube inner surface observation jig 10 according to the present embodiment is effective for observing the setting bolt 2 and the presser bolt 3 that are separated from the inspection nozzle 6 in the axial direction and are located above the overheat reducer H. Therefore, the inside of the large-diameter pipe in the present embodiment means the inside of the pipe having a pipe diameter in which an area where the distal end observation part Vt is brought close to the upper part of the pipe and cannot be sufficiently observed is generated because the fiberscope FS is bent by its own weight. .

In the illustrated tube inner surface observation jig 10, when the fiberscope FS is inserted from the inspection nozzle 6 provided in the superheated steam pipe (large diameter pipe) 1 and the inside of the tube is observed, the tip observation part Vt of the fiberscope FS has its own weight. It is a jig for observation which supports so that it may not bend. In addition, since the internal diameter of the inspection nozzle 6 is a large-diameter pipe in which the general superheated steam pipe 1 has an outer diameter of 800 mm or more, it is easy to ensure at least the extent that a human hand can be inserted.
The pipe inner surface observation jig 10 is connected to a guide tube 11 that forms an inlet opening of the fiberscope FS at one end portion outside the superheated steam pipe 1, a guide tube 11, and a universal joint 20. And a jig body 30 inserted into the superheated steam pipe 1.

The guide tube 11 is a tube material having an inner diameter that allows at least the fiberscope FS to pass therethrough. In the guide tube 11, the outer end of the superheated steam pipe 1 serves as an inlet opening (not shown) for inserting the fiberscope FS. A jig body 30 is connected to the other end side inserted into the superheated steam pipe 1 through a universal joint 20.
The universal joint 20 is connected between the other end of the guide tube 11 and a guide tube 33 with a rack, which will be described later, in a bendable manner, and a hollow portion 21 serving as a guide passage for the fiberscope FS is formed inside. That is, the guide tube 11 and the universal joint 20 are pin-coupled, and further, the universal joint 20 and the rack-equipped guide tube 33 are also pin-coupled. However, since the 45-degree direction change is performed in two stages, it is easy to pass the inserted fiberscope FS.

The jig main body 30 has an insertion state in which the three leg portions 31 are closed so as to have a smaller diameter than the inspection nozzle 6 and an observation state in which the three leg portions 31 are opened and the tip end portion 31a is in close contact with the inner wall surface 1a. An opening / closing mechanism for selectively switching either one of them is provided.
Further, a support cylinder 50 is attached to one of the three leg portions 31 in the vicinity of the distal end portion. The support cylinder 50 faces the axial direction of the superheated steam pipe 1 in the observation state. In addition, it is desirable for the support cylinder 50 to have a telescopic structure which will be described later if necessary.

  Then, starting from the inlet opening of the guide tube 11, the hollow portion 21 of the universal joint 20, the guide tube 33 with a rack of the jig body 30, the fixed portion 32 and the hollow portions 33a, 32a, 31b described later provided in the leg portion 31 are provided. A guide passage (indicated by a broken line in FIG. 1) of the fiberscope FS communicating with the tip outlet 51 of the support cylinder 50 is formed.

The illustrated jig body 30 includes a tripod structure opening and closing mechanism that can be opened and closed by remote control.
In other words, the jig main body 30 includes a fixing portion 32 serving as a base material, and a guide tube 33 with a rack that is fixedly supported by penetrating the vicinity of the central portion of the fixing portion 32 is provided. Accordingly, the fixed portion 32 and the guide tube with rack 33 are integrated components, and the hollow portion 32a formed inside the fixed portion 32 communicates with the hollow portion 33a formed in the guide tube with rack 33. The hollow portion 33a formed in the guide tube with rack 33 is also in communication with the hollow portion 21 of the universal joint 20.

Then, three leg portions 31 are attached to the circular fixed portion 32 in a uniform arrangement. That is, the three leg portions 31 are arranged at an equal pitch (120-degree pitch) in the circumferential direction, and each leg portion 31 is supported in a state where one end is pin-coupled to the fixed portion 32 and can swing. ing. In addition, it is preferable that the front-end | tip part 31a of the leg part 31 is made into R shape in order to improve adhesiveness with the curved pipe inner wall surface 1a.
On the outer peripheral surface (side surface portion) of the guide tube 33 with rack, a rack gear 34 extending in the axial direction from the fixed portion 32 toward the opposite side of the universal joint 20 is formed in a part of the circumferential direction. The guide tube 33 with rack also functions as a shaft that slidably supports the drive unit 35, and the outer peripheral surface on which the rack gear 34 is not formed is a smooth sliding surface.

The drive unit 35 is slidably supported by the guide tube 33 with a rack. The drive unit 35 includes an electric motor 37 serving as a drive source for the pinion gear 36 in addition to the pinion gear 36 that meshes with the rack gear 34. The electric motor 37 is fixedly supported by the drive unit 35 and an operation unit (not illustrated) provided outside the superheated steam pipe 1 by an electric wire (not illustrated) passing through the guide tube 11, the universal joint 20, and the guide tube 33 with rack. The power supply is received through (shown).
As a result, when the electric motor 37 is driven and the pinion gear 36 is rotated, the drive unit 35 moves in any one of the axial directions along the guide tube 33 with the rack according to the rotation direction of the electric motor 37. . Such driving of the electric motor 37 can be remotely operated by the operation unit.

Each of the drive part 35 and the leg part 31 is connected via a link member 38. In this case, both end portions of the link member 38 are pin-coupled that can swing.
As a result, an opening / closing mechanism that opens and closes like a tripod by interlocking the leg 31 is configured in accordance with the sliding direction of the drive unit 35.

Further, in the illustrated configuration example, the support cylinder 50 attached to one of the leg portions 31 has a multi-stage nesting structure including an expansion / contraction mechanism 60 that expands and contracts in the axial direction by remote control. Such an expansion / contraction mechanism 60 enables observation at a position away from the inspection nozzle 6 by extending the support cylinder 50. Further, the support cylinder 50 can be inserted into the gap 5 to observe the state of the setting bolt 2 and the presser bolt 3 as a part that is behind the protective cylinder 4, for example.
In this case, as a preferable expansion / contraction mechanism 60, the rack gear 61 in the axial direction fixedly supported at the distal end portion of the support cylinder 50 having a nested structure, that is, the distal end portion of the thinnest distal end support cylinder 50a, is most retracted. A rack and pinion mechanism that includes a pinion gear 63 that rotates on the outer peripheral surface that is the outer peripheral side, that is, the motor 62 that is fixedly supported by the thickest rear end support cylinder 50b as a drive source can be exemplified.

Hereinafter, with reference to FIG.1 (b), the structure and expansion-contraction operation | movement of the expansion-contraction mechanism 60 are demonstrated concretely.
The support cylinder 50 has an extendable structure, and one end of the rack gear 61 is fixed to the tip of the tip support cylinder 50a by a rack gear fixing point 65. The rack gear 61 is made of a material that can be bent, such as an Insulok (registered trademark) belt.
For this reason, when the rack gear 61 is moved via the pinion gear 63 by driving the electric motor 62, the rack gear 61 is fixed to the outer peripheral surface of the rear end support cylinder 50b so that the bendable rack gear 61 can move smoothly. A plurality of turbulence stoppers 64 are provided. The turbulence stopper 64 prevents the rack gear 61 from being curved and allows the rack gear 61 to slide in the axial direction of the support cylinder 50.

  Further, since the rack gear 61 is an insulation lock strip-like material, it can be bent freely even when inserted from the inspection nozzle 6, and can be bent at right angles inside the superheated steam pipe 1. Since the rear portion of the tube inner surface observation jig 10 is structurally empty, there is no obstacle even if the rack gear 61 extends, and the guide tube 11 is also exchanged when the tube inner surface observation jig 10 is rotated. It is easy to observe, so there is no problem with observation or a series of operations.

  When the telescopic mechanism 60 drives the electric motor 62 and rotates the pinion gear 63, the tip support cylinder 50a connected to the rack gear 61 moves in the axial direction. It expands and contracts according to the direction of movement. That is, if the rack gear 61 moves to the right side of the paper in the axial direction, the support cylinder 50 is extended so as to be pulled out to the front end support cylinder 50a, and the rack gear 61 is moved to the left side of the paper in the axial direction. In this case, the support cylinder 50 is retracted so as to be drawn into the tip support cylinder 50a that is interlocked therewith. Note that the electric motor 62 of the telescopic mechanism 60 can also be remotely operated by the operation unit, similar to the electric motor 37 of the opening / closing mechanism described above.

Further, the support cylinder 50 includes a support cylinder link member 52 in order to always face the axial direction of the superheated steam pipe 1 in the observation state. One end of the support cylinder link member 52 is pin-coupled to the support cylinder 50, and the other end is slidably engaged with a guide groove 38a provided in the link member 38 that connects between the drive unit 35 and the leg portion 31. Are combined. The support cylinder link member 52 is not shown in FIG.
As a result, in the support cylinder 50, the other end of the support cylinder link member 52 slides along the guide groove 38 a, so that the end outlet 51 is always in the axial direction of the superheated steam pipe 1 regardless of the open / closed state of the leg 31. Turn to face.

Further, as shown in FIG. 2, for example, as shown in FIG. 2, it is desirable to attach a sliding member to the distal end portion 31a of the leg portion 31 so that the jig body 30 in the observation state can be easily rotated.
As a suitable sliding member, for example, a structure for attaching a cover member 31b made of Teflon (registered trademark) having a small friction coefficient or a structure for attaching a roller 31c can be exemplified. In FIG. 2, the roller 31 c is attached to the tip of the leg portion 31 to which the support cylinder 50 is attached, and the cover member 31 b is attached to the other leg portion 31, but the cover member 31 b is attached to all the leg portions 31. There is no particular limitation.

  Such a sliding member of the leg portion 31 can easily rotate and move the jig body 30 in the observation state. Therefore, the operation of adjusting the circumferential position of the support tube 50 and changing the observation position in the circumferential direction is performed. It becomes easy. That is, when changing the observation position in the circumferential direction, the opening and closing operation of the leg portion 31 is not necessary, and the jig body 30 only needs to be rotated.

Below, the observation procedure inside a pipe | tube using the pipe | tube inner surface observation jig | tool 10 of the structure mentioned above is demonstrated with operation | movement of each structure part.
In the first jig body insertion step, as shown in FIG. 3, the inspection nozzle 6 of the superheated steam pipe 1 is opened, and the jig body 30 in the inserted state with the leg portion 31 closed is inserted. In this inserted state, the external dimensions of the jig body 30 are smaller than the opening cross-sectional area of the inspection nozzle 6.
After the entire jig main body 30 is inserted into the superheated steam pipe 1, the direction of the jig main body 30 is changed from the universal joint 20 to the axial direction. This jig body direction changing step may be carried out by an operator's hand from the inspection nozzle 6, or may be remotely operated by providing a direction changing drive mechanism as necessary. In addition, FIG. 3 has shown the state which the jig | tool main body direction change process was complete | finished.

  Subsequently, the leg portion 31 of the jig main body 30 is opened, and the leg-opening / alignment process for shifting from the insertion state to the observation state is performed. In this step, when the electric motor 37 is driven by remote operation, the pinion gear 36 rotates and the drive unit 35 moves in the direction of the fixed unit 32, so that the three leg portions 31 are pushed radially open. The three leg portions 31 are aligned so that the jig main body 30 is positioned at the axial center of the superheated steam pipe 1 by having all the tip portions 31a closely contact the pipe inner wall surface 1a of the superheated steam pipe 1. At the same time, it is fixed inside the superheated steam pipe 1. FIG. 4 shows a state in which the leg opening / alignment process is completed, and the support tube 50 in this state has a tip outlet 51 directed in the axial direction of the superheated steam pipe 1.

  Thereafter, the process proceeds to a support cylinder extending step for extending the support cylinder 50, and the motor 62 is driven to rotate the pinion gear 63. As a result, the rack gear 61 that meshes with the pinion gear 63 moves in the axial direction, and the tip support cylinder 50a connected to the rack gear 61 is pulled out in the axial direction and extends to a desired position. Since the support cylinder 50 can enter the gap 5 by setting both dimensions, the support cylinder 50 can be extended to the vicinity of the presser bolt 3 to be observed, thereby completing preparation for insertion of the fiberscope FS.

Thereafter, when the fiberscope FS is inserted from the inlet opening of the guide tube 11, the distal end observation part Vt reaches the distal end outlet 51 of the support cylinder 50 by being guided to the guide passage. At this time, since the fiberscope FS is supported by the support cylinder 50, the tip observation part Vt is not bent by its own weight, and therefore the state of the presser bolt 3 at the upper part of the superheated steam pipe 1 can be observed. It becomes possible.
After the predetermined observation is thus completed, the other presser bolt 3 can be easily observed by rotating the jig body 30 in the circumferential direction as necessary. In addition, by changing the amount of extension of the support tube 50 to observe an observation object having a different axial position, or by appropriately operating the observation scope Vt of the fiberscope FS within a range where the tip observation part Vt does not bend by its own weight. It is also possible to observe the subject.

After all the observations are completed, an operation of taking out the tube inner surface observation jig 10 is performed in the reverse order of the above-described procedure.
That is, after the fiberscope FS is pulled out, the extended support cylinder 50 is contracted to return to the original state, and further, the three legs 31 are closed and returned to the insertion state, and then the reverse of the jig body insertion step. The jig body 30 is pulled out from the inspection nozzle 6 according to the procedure. In addition, after taking out the jig | tool main body 30, all the work is completed by closing the inlet opening of the inspection nozzle 6. FIG.

As described above, in the tube inner surface observation jig 10 of the present embodiment, the jig body 30 is inserted into the superheated steam pipe 1 to be observed from the inlet opening of the inspection nozzle 6, and the leg portion 31 is formed on the tube inner wall surface 1a. By opening and closing, the jig is used to bring the leg 31 into close contact with the inner diameter of the superheated steam pipe 1.
Further, the jig main body of the present embodiment has a structure in which the support cylinder 50 that holds the fiberscope FS is attached to a position close to the inner wall surface 1a of the leg portion 31 and can be expanded and contracted in the axial direction of the superheated steam pipe 1. Therefore, by holding the fiberscope FS with the support cylinder 50, the upper surface side of the large-diameter pipe can be set as the observation target.

  According to the pipe inner surface observation jig 10 of the above-described embodiment, if the fiberscope FS is inserted and observed inside a large-diameter pipe such as the superheated steam pipe 1, the fiberscope FS that is bent by its own weight is used. Since the tip observation part Vt can be held in the vicinity of an observation object at a high place away from the bottom of the pipe, the observation object on the upper surface side of the tube inner wall surface 1a away from the inspection nozzle 6 that is the insertion position can be easily observed. That is, since the bolts installed on the upper side of the overheat reducer H that could not be observed so far, for example, the setting bolt 2 and the presser bolt 3 can be easily and reliably observed, it is effective in improving the soundness of the equipment. .

By the way, in embodiment mentioned above, although the leg part 31 was set to three, it will not specifically limit if reliable fixing and alignment functions, such as using four, for example, can be ensured.
In the above-described embodiment, the electric motors 37 and 62 are used as the drive source for the pinion gears 36 and 63, but other drive sources such as an air motor may be used.
In the above-described embodiment, the support cylinder 50 is attached to one leg 31, but may be attached to a plurality of legs 31.
In addition, this invention is not limited to embodiment mentioned above, For example, it can change suitably in the range which does not deviate from the summary, such as being applicable also to large diameter piping other than the superheat reducer H.

1 Superheated steam piping (large diameter piping)
DESCRIPTION OF SYMBOLS 1a Pipe inner wall surface 2 Setting bolt 3 Presser bolt 4 Protection cylinder 5 Clearance 6 Inspection nozzle 10 Pipe inner surface observation jig 11 Guide tube 20 Universal joint 21, 31b, 32a, 33a Hollow part 30 Jig body 31 Leg part 31a Tip part 31b Cover Member 31c Roller 32 Fixed part 33 Guide tube with rack 34, 61 Rack gear 35 Drive part 36, 63 Pinion gear 37, 62 Electric motor 38 Link member 38a Guide groove 50 Support cylinder 50a Front end support cylinder 50b Rear end support cylinder 51 Front end outlet 52 Support Tube link member 60 Telescopic mechanism FS Fiberscope Vt Tip observation section H Overheat reducer

Claims (4)

A pipe inner surface observation jig that supports the tip observation part when observing the inside of a pipe by inserting a fiberscope from an inspection hole provided in a large-diameter pipe,
A guide tube that forms an inlet opening of the fiberscope at one end that becomes the outside of the large-diameter pipe;
It is connected via the guide tube and a universal joint, and includes a jig body inserted into the pipe from the inspection hole,
An opening / closing mechanism for selectively switching between an insertion state in which a plurality of leg portions are closed so that the jig body has a smaller diameter than the inspection hole and an observation state in which the leg portions are opened and the tip end portion is in close contact with the inner wall surface of the tube; A support tube attached near the tip of the leg and facing the axial direction of the large-diameter pipe in the observation state;
A tube inner surface observation jig characterized in that a guide passage of the fiberscope is formed from the inlet opening of the guide tube through the universal joint, the jig main body, and the leg portion to communicate with the support tube. . The jig body is
A fixing portion which is provided with the guide passage therein and serves as a base material;
A guide tube with a rack that is fixedly supported by penetrating the vicinity of the center of the fixed portion and has a rack gear formed on the outer peripheral surface;
A drive unit slidably provided along the guide tube with the rack;
A pinion gear that rotates with a drive source fixedly supported by the drive unit and meshes with the rack gear;
Three leg portions that are supported at the fixed portion in a swingable manner and are equally arranged in the circumferential direction;
A link member for connecting between the drive part and the leg part,
The tube inner surface observation jig according to claim 1, further comprising a tripod structure opening and closing mechanism that can be opened and closed by remote operation.   The tube inner surface observation jig according to claim 1 or 2, wherein the support cylinder has a multi-stage nesting structure provided with a telescopic mechanism for telescopically extending and contracting in the axial direction. The tube inner surface observation jig according to any one of claims 1 to 3, wherein a sliding member is attached to a distal end portion of the leg portion.

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