JPS6071948A - Automatic flaw detector for circumferential weld zone of piping - Google Patents

Abstract

PURPOSE:To perform exact flaw detection of the circumferential weld zone of a piping by using a conveying carrier which travels in the axial line direction of a guard pipe and a scanning carriage for flow detection which travels in the circumferential direction within said guide pipe. CONSTITUTION:A titled detector consists of an internal piping P having circumferential weld zones apart at a suitable space in the axial line direction of the pipe and a guard pipe Pg fitted onto said piping concentrically therewith. The flaw detection of the weld zones is accomplished by the traveling along the axial direction of the pipe and the traveling in the circumferential direction in the annular space A formed between the two pipes. Rails R1, R2 are laid axially and circumferentially on the inside surface of the pipe Pg. A conveying carriage 1 is mounted on the rail R1 and a scanning carrier 2 for flaw detection provided with an ultrasonic flaw detector 28 is mounted to the rail R2. A cable handling carriage 6 which winds and handles various cables extended between each carriage and a control center installed to the outside is provided on the rail R1. The circumferential weld zones are safely and exactly subjected to flaw detection by the remote automatic operation from the outside if the device is constituted in the above-mentioned way.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to the piping used for the distribution of primary coolant (generally sodium cum is used) in fast breeder reactors that mainly use plutonium fuel. For example, in the inlet piping of a furnace vessel, there are circumferential welds at multiple locations spaced apart in the tube axis direction, and the guard pipe is fitted onto the outside, making it extremely dangerous for humans due to the effects of radioactivity, etc. Periodically or as needed, we conduct flaw detection on the circumferential welds of various types of piping that are located in dangerous or narrow places where people cannot enter due to space constraints, or in long, three-dimensional bends and places where the force of gravity is applied. It is used as a safety measure to prevent fluid leakage from piping, and more specifically, it is used for piping that has circumferential welds at multiple locations spaced apart in the axial direction of the pipe. A piping circle that detects flaws in each of the welded parts by traveling along the pipe axis and along the circumference within an annular space formed between the guard pipe and the guard pipe fitted concentrically. Regarding an automatic flaw detection device for circumferential welds, an object of the present invention is to miniaturize the entire device as much as possible, which is advantageous in terms of storage space during non-operation, and which has a wide range of applicability to pipe diameters.
The object of the present invention is to provide an apparatus with excellent reproducibility that can reliably and accurately perform RfM on a predetermined welding part.

To be more specific, as mentioned above, the inspection target cannot be inspected manually due to manpower, space, and safety issues.
There is also a strong demand for a device that can automatically detect, by remote control, circumferential welds of piping located in difficult locations, especially the circumferential welds of the inlet piping of the reactor vessel mentioned above.

Until now, almost no automatic equipment has been developed to meet such demands.

In addition, in circumferential welds under the above conditions, the weld line is not only a fixed straight line but also many three-dimensional curves, and ultrasonic waves, for example, When performing repeated inspections by periodically scanning a flaw detector, the relative position between the flaw detector and the weld line, that is, the scanning trajectory of the flaw detector relative to the weld line, must be kept constant.
This causes variations in test results, making it impossible to perform highly reliable tests, and as a result, leaks due to test errors occur, which is insufficient as a safety measure. Therefore, there is an urgent need to develop an automatic flaw detection device based on remote control, as well as a device with high reproducibility.

The automatic flaw detection device for circumferential welded parts of pipes according to the present invention was developed in response to the above-mentioned demands at the end of last year, and the characteristic configuration of the automatic flaw detection device for circumferential welded portions of pipes according to the present invention is A transport cart that can be driven and moved in the tube axis direction along rails and can be stopped freely, and a flaw detection scanning device that can be driven and moved in the circumferential direction along circumferential rails installed on the inner surface of the guard tube corresponding to each of the welded parts. When each of the support carts mounted with the carts and the cable handling carts equipped with a mechanism for handling various cables stretched between the carts and the outside of the pipe are transported. They are connected so that they run integrally along the rails by the driving force of the trolley.

To summarize, the characteristic configurations of the present invention are as follows: [I] The cart is self-propelled; [11] The self-propelled cart is driven and runs along rails that are pre-disposed on the inner surface of the guard pipe along the weld lines. 6 things about the so-called moving station type: a support cart equipped with a transport cart that moves in the direction of the tube axis, a scanning cart for flaw detection that moves in the circumferential direction, and a goople process that processes gooples. The present invention has the following three points: It is a combination of three carts, each of which is specialized for a specific function, such as a cart. According to the present invention, which has such a characteristic configuration, the circle 8 In addition to the inherent effects of automatic equipment, such as safely, easily and accurately detecting flaws in welded parts to prevent fluid leaks, etc., and making it possible to perform safe maintenance and management of piping in a labor-saving and rational manner, it also has the following remarkable effects: We can now expect.

In other words, (Illusion) As mentioned in [I] above, since the trolley itself is a self-propelled type equipped with a traveling drive source, it is possible to reduce the number of cables, especially power lines, and compare the overall number of groups. It can be made with low rigidity.

(b) It is possible to bring the entire trolley close to the welded part to be inspected in both the axial direction and one circumferential direction, minimizing the strokes of the inspection trolley and the flaw detector itself, and making it possible to improve their shape. Can be made as compact as possible.

(C) Since various types of cables are processed using a dedicated trolley, and when the entire trolley is evacuated outside the pipe, the cables are processed outside the pipe, so there is no need for a special processing machine inside the narrow pipe.

With the above ((c)), the entire device can be made compact.

■ Due to the low rigidity of the group number, there are fewer restrictions on the running speed of the bogie due to it, and the running speed of the bogie can be set high.
Moreover, it is easy to set the length of the pipe to be inspected by a single truck to be sufficiently large. This increases inspection work efficiency and
It is also advantageous in terms of equipment.

■ Also, as mentioned in [11] above, by constructing a three-wheeled carriage, it is possible to reduce the size of the scanning carriage that moves in the circumferential direction, and to further reduce the diameter of the cables routed around it. , low rigidity can be achieved to ensure smooth and reliable inspection travel, and the entire cart can easily travel around bends when traveling in the direction of the tube axis, and the aforementioned cables can be made smaller in diameter and have lower rigidity. Coupled with smoothness and smooth travel at bends, the scope of application to pipe diameters, pipe lengths, and pipe bend shapes can be significantly expanded.

■ Furthermore, by adopting the station type as mentioned in the E issue, the traveling trajectory of the flaw detection scanning cart relative to the circumferential weld is always constant, even if the circumferential weld is curved. It is possible to completely eliminate variations in test results between S-return tests such as periodic tests. In other words, self-flaw detection of circumferential welds can be carried out with extremely high reproducibility. As described above, the present invention can be applied to
Efficiently performs remote automatic flaw detection of circumferential welds under adverse conditions such as long, bending and 1 gravity action.

We have now been able to provide a device f that is extremely effective in terms of accuracy.

Embodiments of the present invention will be described in detail below based on the drawings.

Figure 1 is a schematic structural diagram of a fast breeder reactor that uses Brutonicum fuel.
This is a steam generator that is transmitted through piping (X) and intermediate heat exchanger (I'IJ to secondary coolant (using sodium) piping), and is driven by the steam generated between these generators as energy. A generator (not shown) is directly connected to the turbine. a?) Concrete wall that seals the ti furnace, (I
11/fi control keyaki drive device.

The object to be inspected in the fast breeder reactor with the above structure is
Coolant pipe (X) # near the inlet of the furnace vessel (101)
: I', as shown in Fig. 2, is constructed by circumferentially welding multiple steel pipes of various types, such as straight pipes and bent pipes, and the welded parts in the circumferential direction ( a) with an internal pipe (Takumi) and a nine-guard pipe (Pg
), the upper end of the guard pipe (Pg) has a gate (b) for entering and exiting the device, and both the inner and outer pipes (P), (P
g) Each of the welded parts ( The apparatus for sequentially testing a) is constructed as follows.

As shown in FIGS. 8 to 7, the guard pipe (Pg
), a bogie running rail (R1) with a continuous disc brake plate α is laid over the entire length of the pipe to be inspected (P) in the same direction, and The guard pipe (which corresponds to the welding part)
Pg) On the inner surface, a circumferential rail (R8) with a continuous cast disc brake plate me is laid with a cutout at a location corresponding to the bogie travel path on the lrl rail (Rs).

The bogie is in elastic contact with the outer surfaces of both sides of the former rail (R+) and is rotatably driven via a motor wheel with a brake, and has a pair of rubber-lined drive wheels (5), a bezel, and the disc brake plate α. The rail (R1) is equipped with a disc brake blade that acts on the rail, a pulse encoder (7) for controlling the stop position of the bogie in the tube axis direction, and the like.
A transport carriage (1) that can be freely driven and stopped along the tube axis direction, and a motor with a speed reducer that engages rack-shaped teeth 11 (Rsb) formed on the inner peripheral surface of the latter circumferential rail (R1). A pair of rotatable gear-like drive wheels (c), a disc brake blade that acts on the disc brake plate, a pulse encoder, and an ultrasonic flaw detector (c).
And this is determined by the contact ratio (S/
Machine 4# to keep the N ratio constant! υ, etc., and is equipped with a scanning trolley (2) for flaw detection that can be driven and moved in the circumferential direction on the circumferential V-rule (Rm), and a local area corresponding to the trolley movement path is mounted. The support cart (3) to which the rail portion (Rta) is attached, and each of the above-mentioned carts (su,
When the fil, +3) travels, the various trolleys (it), (21, (21) are installed outside the guard pipe (Pg) and stretched across the nine control centers (not shown). Cables, specifically power goople (4A), optical fiber for communication (4B), safety cable (4C1, and although not shown, image 7 eye/(- cable, UT sensor choir to have room for circumferential movement) A box containing a light conversion device, a relay external switch, etc. (5
A), Winder (5B), Pinch roll for feeding (5C)
, dynamic cable relay pock M and the rail (R
1) is divided into a cable handling trolley (6) equipped with wheels (goods) etc. that move in a convex manner, and each of these trolleys + Ll
, 131, (3) is conveyed to the transport vehicle i1+ via cti, which has an axis perpendicular to the tube axis direction.
They are connected so that they run integrally along the rail (R□) by the driving force of the rail. In addition, the support cart (3) has a local rail portion (Rsa) attached thereto.
A limit switch (LS) and a stopper mechanism are provided to accurately match and connect and fix the guard pipe (Pg) to the circumferential rail (R1) laid on the inner surface of the guard pipe (Pg). It is controlled to one precision position from a circle for rail alignment.

FIG. 8 shows another embodiment, in which an air cylinder is used as the drive mechanism for the travel drive motor, the suspension mechanism ωl, and the stopper mechanism M4I. The supply is in the chamber (6
). In addition, liquid nitrogen (L City) is also used to cool and keep the equipment mounting section of the trolley cool, but as shown in Figure 9, the extraction nipple is installed at the fixed position of the air pipe and the liquid nitrogen pipe. The coupler is then automatically inserted and connected by a coupler insertion drive motor installed on the transport vehicle i1) to fill and supply air and liquid nitrogen into the chamber at each station.

The device of the present invention can be made even more effective by adding configurations and functions that will be explained below.

■ In order to prevent a decrease in the positional accuracy of the support cart and scanning cart due to relative positional deviation between the internal knoll and the welded part to be inspected due to assembly errors, etc., confirm the existing position by mechanical finishing etc. By attaching, for example, a protruding reference mark in advance to the part of the weld where it would be difficult to perform flaw detection, the support truck can be stopped and the scanning truck can be moved using this reference mark. Inspections can be carried out effectively and accurately.

■ In an emergency such as when the remoter cannot be driven due to a power outage etc. during a flaw detection inspection, the i
By configuring the various types of gooples, including the support cart and the transport cart, to be automatically wound up using the mechanical force of a spring in response to the pulling back of a safety cable provided between the outside of the pipe and the cart. Even in emergencies such as power outages,
The entire truck can be pulled out of the pipe without any undue twisting or tangling of the cables.

Further, in the device of the present invention, the support truck

[Brief explanation of drawings]

The drawings show an embodiment of the automatic flaw detection apparatus for circumferential welded parts of piping according to the present invention, in which Fig. 1 is a schematic structural diagram of a fast breeder reactor, Fig. 2 is a side view of the piping part to be flaw-detected, and Fig. 8 is a schematic diagram of the structure of a fast breeder reactor. Figure 2 is an enlarged cross-sectional view along the line ■-■, Figure 4 is a three-dimensional schematic diagram of the entire device, Figures 5 and 6 are a plan view and side view of Figure 4, and Figure 7 is an enlarged cross-section of the main parts. Figure 8 is a three-dimensional schematic diagram of the entire device according to another embodiment, and Figure 9 is! This is due to the perspective view of the jig used in Figure g8. .

Claims (1)

[Claims] ■ A pipe (P) having circumferential welds (1) at multiple locations spaced apart in the pipe axis direction, and a guard pipe (Pg) externally fitted concentrically with the pipe (P). A device for detecting flaws in each of the welds*(a) by traveling in the tube axis direction and traveling in the circumferential direction within the annular space (8) formed between the guards. A transport cart (1) that can be driven to move and stop freely in the pipe axis direction along the rail (R1) laid on the inner surface of the pipe (Pg), and a guard pipe (Pg) on the inner surface corresponding to each of the welded parts (,). A flaw detection scanning trolley (
2) on which the support cart (3) is mounted, as well as each of the above-mentioned carts (
1), il+, (When 31 moves, these trolleys +1), 121, (: Various cables (4A) stretched across ll and the outside of the pipe (Pg)
, 4B. 4C) is coupled to a cable processing cart (6) equipped with a mechanism (6) for processing (4C) so as to run integrally along the rail (R+) by the driving force of the transport cart 111. Automatic flaw detection equipment for piping circumference welds. ■ Claim 0 in which the three carriages +11, 13) and tel are connected in a pin joint type.
An automatic flaw detection device for piping circumferential welds as described in 2. ■ The support truck (3) is provided with a rail portion (R1) corresponding to the movement path of each truck (1), (sl, (61) in the tube axis direction of the circumferential rail (R1). An automatic flaw detection device for a circumferential welded part of a pipe according to item 0 of the scope of special 11FM clothing.
, (81) Automatic detection device for circumferential welded portions of pipes according to claim 0, which is equipped with a pulse encoder (7) for controlling the stop position in the direction of the pipe axis.