JPH03211456A - Ultrasonic probe for boiler tube flaw detection - Google Patents

Abstract

PURPOSE:To detect cracking in the axial direction of a tube in the best state and to easily pass a curved tube part by making the probe eccentric in a radial direction according to the internal passage of the tube and storing the eccentric probe in the cut part of a probe main body at the curved tube part. CONSTITUTION:The probe main body 7 is provided with cantilevers 8a and 8b symmetrically by using a pin 9 and also fitted with probes 6a and 6b, and the quantity of eccentricity is adjusted with a cap nut 12 for eccentricity quantity adjustment. Spring shafts 13 are fitted before and behind the probes 6a and 6b, which are driven and rotated by a shaft 13 and a rotor shaft 14 in double structure. Then when the probes pass through the curved tube part, a lever 8b and the probe 6b which contact the internal wall of the tube are stored in the cut part of the main body 7. The probe 6a is also the same. Consequently, the cracking in the axial direction of the tube can be detected in the best state at all time and the probes can pass through the curved tube part smoothly.

Description

[Detailed Description of the Invention] [Field of industrial application] The present invention is a method for removing cracks in the pipe axis direction that occur in the welded parts of metal fittings of a gayra chape from the inside of the pipe by a water immersion method. Regarding an ultrasonic probe for deep wounds.

[Conventional technology]

Do not apply adhesives to the contact parts of the superheater, reheater, etc. of the fireworks.
A fatigue crack occurs due to thermal stress caused by Vc#.

However, the superheater and the 7I! For percentage instruments etc., the chain interval is 5
Due to the 0 to 100 earthquakes, Surveyor A cannot approach. For this reason, fatigue cracks have conventionally been confirmed by taking the entire sample tube.

[Problem to be solved by the invention]

As mentioned above, there is no suitable non-destructive inspection method for cracks that occur in locations that cannot be accessed by inspectors, such as the welded parts of adhered metals in the superheater and reheater of a thermal power plant. Therefore, the presence or absence of cracks has been confirmed by taking a sample tube and conducting a destructive investigation. As a result, the survey locations were limited, and a large amount of costs were required to restore the sample collection locations.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide an ultrasonic probe for mailer chain flaw detection that can non-destructively inspect cracks that occur in the contact area of attached metal 1'l of boiler chases. shall be.

[Means to solve the problem]

The present invention uses ultrasonic water immersion to detect cracks in the pipe axis direction that occur in locations where inspectors cannot access the welded parts of adhered metal such as superheaters and reheaters in fireworks. This relates to a rotary probe for non-destructive detection using the method, and has an eccentric mechanism that decenters the probe by an arbitrary amount in the radial direction of the tube depending on the inner diameter of the tube. , and the mechanism for rotating the probe within the tube and the bent tube section include a support mechanism for housing the eccentric probe within the probe body.

[Effect]

According to the above configuration, it is possible to non-destructively inspect the cracks that occur in the welded parts of the metal fittings of the final pipe from the inside of the tube by using the water immersion method of ultrasonic flaw detection. It is possible to inspect the welded parts of adhered metals such as superheaters and reheaters. There is also no need to polish the outer tube surface for inspection. In addition, in order to detect cracks in the tube axis direction, the probe can be decentered by an arbitrary amount in the radial direction according to the tube specifications, making it possible to detect cracks in heat exchangers where loops are formed with tubes of different diameters. 1
(This is possible with a single rotary probe), and since the eccentric probe is housed in the probe body in a curved pipe section, it is also easy to insert into the pipe.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

Figure 1 shows the procedure for detecting an Ω crack 4 in the axial direction of the hole tube, which occurs in the welded part 3 of the metal fitting 2 attached to the mailer tape 1, using ultrasonic waves from inside the tape 1 through water 5. . As shown in FIG.
It needs to be eccentric.

Figure 2 shows the relationship between the eccentricity of the probe and the defect echo height for several types of tubes commonly used as superheater tubes. It can be seen that flaw detection sensitivity is highest when

FIG. 3 is a side view showing the configuration of the rotary probe of the present invention. This rotary probe is used to detect cracks in the tube axis direction from the inside of the tube, and two cantilevers 8* and 8b are symmetrically attached to the probe body 7 with cannalever stoppers 9. It is being Probes 6h and 6b are attached to the cantilevers 8* and 8b, respectively. Nine, the two cantilevers 8* and 8b always try to be eccentric due to the spring 10 and pin 1 attached to the fulcrum part (cantilever fixing pin 9 part), but the probe body 7 has a device for adjusting the amount of eccentricity. Since the cap nut 12 is screwed together, it can only be eccentric to a position where it comes into contact with the cap nut 12.

Furthermore, in this embodiment, spring shafts 13 are attached to the front and rear of the probe 61.degree. 6b in order to mount a jig for centering the probe body yt-all. As shown in FIG. 6, this sliding shaft 13 is built into the eccentricity adjusting cap nut 12 and directly connected to the nine bearing 31. The probes 6*, 6b are rotationally driven by a rotor shaft 14 which has a double structure with a spring shaft 13.

That is, as shown in FIG. 6, a bearing 31 is provided between the probe body 7 and the spring shaft 13, and the probe body 7 and the rotor shaft 14 are directly connected with a set screw 32. Due to the rotation of the rotor shaft 14, the probe Mokujun 7 also rotates.

FIG. 4 shows how the rotary probe of the present invention passes through I*ff1l. The cantilever 8b and the probe 6b, which came into contact with the inner wall of the tube when passing through the curved tube H of the mailer tape 16, are housed in the notch of the probe body 7. The same applies to the probe 6a. This allows for smooth passage through blood vessels. However, when the cantilever 8b and the probe 6b, which are housed in the notch, move through the curved pipe section and move to the straight pipe section, the eccentricity g4! It is possible to detect cracks in the tube axis direction by using this hole, which is set in advance with the cap nut 12 for Ii and protrudes (I center) at the next position ll1t.

That is, as shown in FIG. 6, when the nut 12 is screwed in the direction of the arrow, the cantilever 8b moves in the direction of the arrow B, and the amount of eccentricity of the probe 6b appears small. Maku, Natsu 1
When probe 2 is moved in the opposite direction to the arrow entry direction, probe 6
The amount of one core of b increases. The same applies to the probe 6a. In this way, the probe St is set in advance using the eccentric i1c nuts 12 of the contacts 6* and 6b.
(varies depending on pipe specifications).

FIG. 5 is a diagram showing a state in which a temporary sweeter weld (weld in the tube axis direction) of a final trap is being flaw-detected using the rotary probe of the present invention. In FIG. 5, the probe main body 7 is attached to the centering jig 17 installed at the front and rear of the probe main body 7.
It is held on the centerline of the mailbox 216. Probe 6
*, 6b is a certain amount of eccentricity in the butterbur? The inside of the eraser f1g is fully rotated, and the flaw detection of the welded parts of the attached metal parts is carried out.
In the figure, 18 is an alignment jig valve spring, 19 is a presser foot adjustment nut, 20 is a guide, 21 is a welding part, and 22
is a temporary sweeter.

Here, the alignment mechanism of the alignment jig 17 and the guide 2Q
We will explain the structure of

The centering jig 17 is made of nylon 33.

During manufacturing, the number of materials per piece and the length of the materials are controlled, and as shown in Figure 7, if the diameter of the centering jig 17 is larger than the inner diameter of the tube, the nylon 33 will be crushed uniformly. , alignment of the probe body 7 becomes possible. In this case, the probe body 7
If the alignment is poor, the eccentricity of the probes 6m and 6b will not be constant during rotation, making flaw detection impossible. In addition, the guide 20 is
A goal made of Teflon is attached to the tip of the spring shaft 13 to prevent the tip of the spring shaft 13 from getting stuck where there is a protrusion such as the inner surface of a welded part. This guide 20 is fixed to the spring shaft 13 with screws.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to detect cracks in the welded part of the adhered metal of the cedar chain from the inner surface of the pipe by the water immersion method, so there is no need for polishing for inspection. In addition, it has a function to decenter the probe by an arbitrary amount in the radial direction according to the pipe specifications, so cracks in the pipe axis direction can always be detected in the optimal condition. When doing so, the eccentric probe is housed in the notch of the rotary contact body, so it passes smoothly through the curved pipe section.

Furthermore, since a two-channel system is used, and one probe is used to confirm the entire position of the melt overfill, the remaining probe is used to detect the flaw, so there is no mistake in the flaw detection position.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining a flaw detection method according to an embodiment of the present invention, FIG. 2 is a diagram showing the relationship between the eccentricity of the rotary probe and the defect echo height of the same embodiment, and FIG. The figure is a side view showing the configuration of the rotary probe of the same embodiment, FIG. 4 is a side view showing how the rotary probe of the same embodiment passes through the curved pipe section, and
The figure is a perspective view showing how the rotary probe of the same embodiment detects flaws in the welded part, and FIG. 6 is a diagram showing the configuration of the rotation mechanism of the rotary probe of the same embodiment. , FIG. 7 is a diagram for explaining the alignment mechanism of the alignment jig of the same embodiment. 6a and 6b... probe, 7... probe body, 8
& and 8b...Cantilever 9...Cantilever stopper, 10...Spring, 11...Bin, 12.
...Natsuto, 3...Spring shaft.

Claims (1)

[Scope of Claims] A rotary probe for inspecting cracks in the axial direction of a tube from the inside of the tube using the water immersion method of ultrasonic flaw detection, the probe being The tube is provided with an eccentric mechanism that decenters the tube in the radial direction, a rotation mechanism that rotates the probe within the tube, and a support mechanism that supports the probe so that it can be stored in the probe body. An ultrasonic probe for IRATUBE flaw detection.