JPS647322Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a flaw detection device for pipe walls of various standing pipes such as heating pipes for steam catalytic reforming installed upright in a furnace. A machine body is provided that is detachable from the pipe and can be moved freely in the longitudinal direction of the pipe to be inspected and stopped by remote control, and water is filled between the body and the surface of the pipe to be inspected. A pipe flaw detection device in which a water immersion type transmitting probe that projects ultrasonic waves onto the pipe and a water immersion type receiving probe that receives the ultrasonic waves transmitted through the pipe to be inspected are installed in the body. Regarding equipment.

The above-mentioned water immersion type flaw detection device presses a probe for transmitting and receiving ultrasonic waves against the surface of the tube to be inspected, and fills water between the probe and the tube surface to emit ultrasonic waves. By increasing the transmittance and projecting ultrasonic waves from the transmitting probe to the receiving probe, the pipe is non-destructively detected based on changes in the attenuation of the ultrasonic waves passing through the pipe wall. Alternatively, the flaw detection is used to detect aging of the pipe and estimate the lifespan of the pipe based on that, and since the flaw detection work can be performed remotely, it is necessary to erect a high scaffold. Flaw detection work can be carried out safely and with good workability. During this flaw detection process, as mentioned above, water is filled between the tube surface and the probe to increase the transparency of the ultrasonic waves, but the surface of the tube to be inspected remains as a cast surface. If the roughness of the pipe surface is poor, such as when the surface is rough, scale has formed on the surface due to oxidation, or foreign matter has adhered to the surface, the surface of the pipe may deteriorate even if water is constantly supplied. The water may not fill immediately and sufficiently into the minute recesses of the
As a result, the transmittance of ultrasonic waves decreases, and this leads to a decrease in detection accuracy.

An object of the present invention is to enable water to be sufficiently and reliably filled between the tube surface and the probe in an upright tube to be inspected.

The characteristic configuration of the tube flaw detection device of the present invention is that a plurality of nozzles are provided above both probes along the circumferential direction of the tube to be inspected for supplying water to the surface of the tube to be inspected when attached to the tube to be inspected. The functions and effects are as follows.

In other words, the water supplied from the nozzle to the pipe surface is
Even if the flow does not flow directly downward depending on the roughness of the tube surface, multiple nozzles are arranged above both probes along the circumferential direction of the tube to be inspected.
The water supplied from any one of the plurality of nozzles can reliably pre-soak the tube surface portion through which ultrasonic waves are transmitted, and fill the space between the tube surface and the probe with sufficient water.

Therefore, regardless of the roughness of the tube surface, highly accurate flaw detection can always be performed while moving the vertically installed tube to be inspected in its length direction.

Next, embodiments of the present invention will be described in detail based on the drawings.

As shown in Figures 1, 2, and 6, one end of a pair of circular arc members provided with a large number of rollers is connected with a pin, and a releasable elastic engagement connection mechanism is provided at the other end. are provided to form two sets of holders 1, 1, rods 2, 2 are provided across the arcuate members on one side of the two sets, and relative positions are provided across the rods 2, 2 in the longitudinal direction. Curved members 3, 3 are installed so that they can be changed and fixed freely, and frames 5, 5, each of which has a concavely curved surface that contacts the pipe 4 to be inspected, are mounted on opposing surfaces of the members 3, 3 in the circumferential direction of the pipe 4. A pair of transmitting probes 6 for emitting ultrasonic waves and a receiving probe 7 for receiving the ultrasonic waves are attached to a spherical structure with a hollow part 8 and a water inlet 9. It is installed inside the blocks 10, 10, and the blocks 10, 10 are attached to the frames 5, 5 so as to be able to change their posture around the spherical center, and pipes 30, 30 closed at both ends along the arc shape of the holder 1 are provided. , when viewed in the axial direction of the rod 2, the frames 5, 5
The nozzles 31 facing the center of the holder 1 are attached to each of the pipes 30, 30 at appropriate intervals along the circumferential direction of the pipe 4 to be inspected. The flaw detection device 11 is constructed by forming a plurality of pipes 30, 30 and connecting flexible water supply pipes 33, 33 to a pipe 32 connected to the pipes 30, 30.

As shown in FIGS. 1 and 3, a traveling device 14 consisting of rollers 12, 12 driven by a motor around a horizontal axis and an endless belt 13 wound around the rollers is attached to a box-shaped frame 15, and the traveling belt is 1
A self-propelled body 17 is constructed by installing rollers 16 on the box-shaped frame 15 to elastically clamp the tube 4 to be inspected in cooperation with the rollers 16 and 3.

The rollers 16 for holding the tube include:
Cylindrical bodies 18 are installed in the horizontal direction on both sides of the frame 15 and spaced apart vertically, and a shaft 20 having a roll 19 at its bent tip is fitted into the cylinder 18 so as to be slidable and rotatable. , a spring 21 is provided between the shaft 20 and the cylindrical body 18 for drawing and biasing the roll 19 toward the box-shaped frame 15, and locking pieces 22 having an I-shaped cross section are provided between the upper and lower cylindrical bodies 18, 18. In addition to providing the spring 21
A lever 23 that can be freely released from engagement against the urging force of
are connected to each of the bending shafts 20, and the rolls 19
The self-propelled body 17 can be engaged with and detached from the tube 4 to be inspected in a state in which the self-propelled body 17 is positioned outward from the axis of the cylinder 18, and by reversing the rolls 19 when in the state of engagement with the tube 4, The self-propelled body 17 can be elastically clamped to the tube 4 by the rolls 19 and the belt 13, and in this state, the self-propelled body 17 can be operated for self-propelled and stopped by a remote control tool (not shown) for the traveling device 14. It is designed so that it can be done.

The self-propelled body 17 is provided with an engaging member 24 that engages and disengages from the tube 4A to be inspected adjacent to the tube 4 to be inspected as a guide, and the body 17 travels on the tube 4 to be inspected. When doing so, the pipe 4
Due to the effects of surface irregularities and welded parts, the fuselage 17
Rotation in the circumferential direction is suppressed.

A flaw detection device connector 25 is provided at the bottom of the self-propelled body 17.

This connecting tool 25 includes hooks 27, 27 that engage with connecting pins 26 attached to the holder 1 on the side provided with the water supply nozzles 31, and a device to prevent the hook 27 from coming off, which is biased by a spring 28. It is equipped with 29,29.

For example, when testing a heating tube for steam catalytic reforming in which centrifugally cast tubes made of austenitic heat-resistant cast steel or the like are welded together and many of the tubes are installed vertically in a furnace, the first step is to conduct a flaw detection inspection on the tube 4. The flaw detection device 11 is suspended and held by the self-propelled machine body 17 and externally fitted onto the vertical pipe 4 to be inspected, and the engaging member 24 is engaged with the adjacent vertical pipe 4A, and the flaw detection device 11 is suspended and held by the self-propelled machine body 17. Align to the target location.

Then, the relative positions of the upper and lower pairs of transmitting and receiving probes 6 and 7 are made different in the circumferential and longitudinal directions of the tube 4 to be inspected, and parallel circles of the same diameter are arranged along the outer periphery of the tube 4. The probes 9, 7 and the tube 4 to be inspected are separated by setting positions on the circumferences P, P at predetermined angles and intervals, and constantly supplying water to the hollow parts 8, 8 through the water supply ports 9, 9. At the same time, water is filled between the surfaces, and water is supplied to the tube to be inspected above the flaw detection device 11 through the nozzles 31..., and the water flowing down from these along the tube wall is transferred to the tube to be inspected 4.
The ultrasonic waves A are projected from the transmitting probe 6 toward the receiving probe 7 while being collected in a container 34 provided at the bottom of the probe.

Then, as shown in FIG. 5, the ultrasonic wave A projected with an incident angle θ ₁ has an angle θ
At the same time, the wave is refracted and transmitted through the thickness of the tube 4 in the tangential direction, and is also refracted at an angle θ at the incident point C and received by the receiving probe 7. If a defect f exists, the reception probe 7 detects the attenuated transmitted ultrasound, thereby detecting the presence of the defect f at the target location.

By sequentially performing the above flaw detection inspection while moving the flaw detection device 11 up and down in the longitudinal direction of the tube 4, and by changing the position of the flaw detection device 11 in the circumferential direction of the tube 4, it is possible to conduct multiple inspections around the tube over the entire length of the tube 4. Point flaw detection inspection can be performed.

Since the ultrasonic waves A are scanned obliquely, flaw detection at the butt weld between the tubes can be performed with high accuracy.

That is, when the ultrasonic waves A are simply scanned in the circumferential direction of the tube 4, the irregularities on the outer surface of the weld bead greatly affect the ultrasonic attenuation, making it extremely difficult or impossible to determine whether or not it is a defect. By scanning the ultrasonic wave A from the base metal through the weld zone, the negative effects of the irregularities on the outer surface of the weld bead can be greatly suppressed, and even the weld zone can be inspected with high accuracy. .

Further, since the relative positions of both the probes 6 and 7 are configured to be changeable, it is possible to cope with changes in the outer diameter or wall thickness of the tube 4 to be inspected.

In the above flaw detection work, since water is filled between the probes 6 and 7 and the surface of the tube to be inspected 4, ultrasonic waves
Of course, it is possible to increase the transparency of
The probe 6 when the flaw detection device 11 is moved upward,
Nozzle 3 is placed on the pipe to be inspected next time.
By supplying water from 1... and allowing water to penetrate the surface of the pipe to be inspected in advance, even if the surface roughness of the pipe is poor, the probes 6 and 7
It is possible to immediately fill enough water between the
High flaw detection accuracy can be maintained by avoiding the influence of tube surface roughness.

[Brief explanation of the drawing]

The drawings show an embodiment of the pipe flaw detector according to the present invention, with Fig. 1 being an overall perspective view, Fig. 2 being a cross-sectional view of the main part, Fig. 3 being a detailed view of the connector, Fig. 4 being a cross-sectional view of the self-propelled body, Fig. 5 being an explanatory view of flaw detection, and Fig. 6 being a perspective view of the flaw detector. 4: pipe to be inspected, 6: transmitting probe, 7: receiving probe, 17: self-propelled body, 31: water supply nozzle.

Claims (1)

[Scope of utility model registration request] A body 17 is provided which can be freely attached to and detached from the upright pipe 4 to be inspected, and which can freely run and stop in the longitudinal direction of the tube 4 to be inspected by remote control. A water immersion type transmitting probe 6 that projects ultrasonic waves onto the tube 4 to be inspected with water filled in between, and a water immersion type receiver that receives the ultrasonic waves transmitted through the tube 4 to be inspected. This is a tube flaw detection device in which a probe 7 is installed on the body 17, above both the probes 6 and 7, and on the surface of the tube 4 to be inspected when attached to the tube 4 to be inspected. The nozzle 31 for water supply,
A plurality of tube flaw detection devices are arranged along the circumferential direction of the tube 4 to be inspected and are attached to the body 17.