JP2008100266A - Inspection apparatus for defective brazing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inspection apparatus for defective brazing, capable of obtaining a highly reliable result of inspection in a short time when inspecting a brazed joint part of piping. <P>SOLUTION: An inspection apparatus 50 for defective brazing inspects the defective brazing in a brazed joint part 9, which is formed by expanding the end part of piping 8B, inserting the end part of the other piping 8A into the inner periphery of the expanded end part, and jointing the end parts of both piping by brazing. The apparatus 50 is provided with an inspection part capable of moving around the outer periphery of the brazed joint part at least once. The inspection part is provided with a plurality of probes 57A, 57B, 57C, which are arranged axially in the brazed joint part 9 in multi-rows and inspect defective brazing while being in contact with the outside of the piping 8B and transmitting/receiving ultrasonic waves. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a brazing defect inspection apparatus that inspects a brazing defect of a brazed joint portion of piping using ultrasonic waves.

In some cases, refrigerant piping such as a refrigerator is joined by brazing. If poor brazing occurs at the joint, refrigerant leakage may occur. As a method for inspecting the brazing joint of the refrigerant pipe, a destructive inspection method in which the brazing joint is cut and the state of the brazing material is visually inspected is generally used.
Also, for pipes that are joined by joining an O-ring member to the joint instead of joining by brazing, whether or not the O-ring is firmly interposed in the joint is inspected using ultrasonic waves. There is a known method (see, for example, Patent Document 1). In this inspection method, ultrasonic waves are irradiated from the outside of the position where the O-ring member is interposed, and whether or not the O-ring member is normally inserted is evaluated based on the intensity of the reflected wave.
JP-A-8-270875

However, in the conventional configuration, when the brazed joint portion of the refrigerant pipe is inspected by the above destructive inspection method, it is necessary to physically cut the brazed joint portion, which causes a problem that the inspection takes time.
In addition, when a brazed joint is inspected by a method similar to the method of inspecting an O-ring joint by ultrasonic waves, it cannot be inspected whether or not the brazing material is spread over the joint, and is reliable. The test result cannot be obtained.
Also, refrigerant pipes for refrigerators, etc. must be brazed and joined to complete the refrigerator, and then a brazing defect inspection must be performed. Generally, however, the brazed joint refrigerant pipe is located in a narrow area. However, there is a problem that a large inspection instrument cannot be used.

  The present invention has been made in view of the above-described circumstances, and provides a brazing defect inspection apparatus capable of obtaining a highly reliable inspection result in a short time when inspecting a brazed joint portion of a pipe. For the purpose.

  In order to achieve the above object, the present invention expands the end of one pipe, inserts the end of the other pipe into the inner periphery of the expanded end, and brazes the ends of both pipes. In the brazing defect inspection apparatus for inspecting a brazing defect in the brazed joint joined by the step, an inspection part capable of moving at least once around the outer periphery of the brazed joint is provided. A plurality of probes arranged in multiple rows in the axial direction and inspecting for brazing defects while contacting the outside of the pipe and transmitting and receiving ultrasonic waves are provided.

  According to this invention, since the brazed joint portion of the pipe is inspected by ultrasonic waves, it is possible to reduce the time required for the inspection, and furthermore, ultrasonic inspection is performed at a plurality of locations in the circumferential direction and the axial direction of the pipe. Since it is performed automatically, a highly reliable test result can be obtained.

Moreover, the present invention is characterized in that, in the above-mentioned invention, the inspection part is configured to be capable of self-propelling on the outer periphery of the brazed joint part.
Further, the present invention is the above invention, wherein the inspection section is attached to a drive motor, guide wheels attached to both ends of the shaft of the drive motor, and capable of rolling on the outer periphery of the brazed joint, and the shaft. A probe mounting portion that supports a plurality of probes, and the shaft and the pipe are connected by a detachable mounting band so that the inspection portion can be attached to the brazed joint portion. Features.

  According to the present invention, the brazing defect inspection device is connected to the pipe by the mounting band and is self-propelled during the inspection. Therefore, it is possible to easily perform the brazing defect inspection even in a narrow part such as a joint portion of the refrigerant pipe. it can.

  According to the present invention, since the brazed joint portion of the pipe is inspected by ultrasonic waves, it is possible to reduce the cost and time required for the inspection, and in addition, ultrasonic waves at a plurality of locations in the circumferential direction and the axial direction of the pipe. Since the inspection is performed automatically, a highly reliable inspection result can be obtained.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic diagram showing a refrigerant circuit of the refrigerator 1. As shown in this figure, the refrigerator 1 includes a compressor 2 that converts a low-temperature and low-pressure gaseous refrigerant that has been sucked into a high-temperature and high-pressure gas, a condenser 3 that liquefies the introduced refrigerant, a receiver 4, An expansion valve 5 that decompresses the sucked liquid refrigerant to make it a low-temperature and low-pressure liquid, an evaporator 6 that evaporates the sucked liquid refrigerant at a predetermined temperature, and separates the sucked refrigerant into gas and liquid. These devices are sequentially connected via a copper refrigerant pipe 8 to form a refrigeration cycle. The refrigerator 1 is filled with a refrigerant under pressure, and this refrigerant circulates in the direction of the refrigeration cycle as indicated by the dashed arrow in the figure.

  The said refrigerant | coolant piping 8 has connected said each apparatus by joining by brazing. FIG. 2 is a cross-sectional view of one brazed joint 9 out of locations joined by brazing (hereinafter referred to as “brazed joint”). As shown in this figure, in the brazed joint 9, the end of one refrigerant pipe 8B is expanded, and the end of the other refrigerant pipe 8A is inserted into the expanded part of the refrigerant pipe 8B. The entire boundary surfaces of the refrigerant pipes 8A and 8B are brazed with the brazing material 10.

  FIG. 3 is a diagram showing a brazing defect inspection apparatus 50 (hereinafter simply referred to as “inspection apparatus 50”) according to the present embodiment. This inspection apparatus 50 is an apparatus for inspecting that the brazing filler metal 10 is evenly distributed over the entire boundary surface of the refrigerant pipes 8A and 8B in the brazing joint portion 9. When the brazing material 10 does not reach the entire boundary surface, these are detected.

  The inspection apparatus 50 includes a drive motor 51, a shaft 52 that transmits the rotational driving force of the drive motor 51, and rubber guide wheels 53A and 53B attached to both ends of the shaft 52. The guide wheels 53 </ b> A and 53 </ b> B are configured to rotate according to the rotation of 51.

  A control device 55 such as a personal computer is connected to the drive motor 51 via a cable 54 so that various signals such as control signals can be transmitted and received between the drive motor 51 and the control device 55. The control device 55 can adjust the rotational speed of the drive motor 51 by transmitting a travel control signal to the drive motor 51 via the cable 54. Note that the control device 55 includes components included in a general personal computer such as a storage unit and a display unit.

A probe attachment portion 56 is attached on the shaft 52. Probes 57A, 57B, and 57C that transmit ultrasonic waves and detect reflected waves are attached to the probe attachment portion 56. An ultrasonic signal processing device 59 is connected to the probes 57A, 57B, and 57C via cables 58A, 58B, and 58C, and an ultrasonic wave is transmitted between the probes 57A, 57B, and 57C and the ultrasonic signal processing device 59. The signal can be transmitted and received.
In addition, a control device 55 is connected to the ultrasonic signal processing device 59 via a cable 60 so that various signals can be transmitted and received between the ultrasonic signal processing device 59 and the control device 55. .

  A pair of rubber mounting bands 61, 61 are wound between the shaft 52 and the refrigerant pipe 8, and the guide wheels 53 </ b> A, 53 </ b> B are pressed against the outer periphery of the refrigerant pipe 8 by tightening the mounting bands 61, 61. As a result, the inspection device 50 is attached to the refrigerant pipe 8. When the guide wheels 53A and 53B are rotated by the drive motor 51, the inspection device 50 is tightened toward the center of the refrigerant pipe 8 by the attachment bands 61 and 61 and maintains the predetermined position in the axial direction of the refrigerant pipe 8 while maintaining the predetermined position. It is configured to travel in the eight-round direction. The tips of the probes 57A, 57B, and 57C are in light contact with the outer peripheral portion of the refrigerant pipe 8B. When the inspection device 50 travels in the circumferential direction of the refrigerant pipe 8, the tips of the probes 57A, 57B, and 57C are refrigerant. The vehicle travels in contact with the pipe 8B.

Next, the operation of the inspection apparatus 50 during inspection will be described with reference to FIG.
When inspecting the brazed joint 9, information such as the size and material of the diameter of the refrigerant pipe 8 of the brazed joint 9 is stored in the storage unit of the control device 55 in advance and is made into a database. The information stored in the database is used when the control device 55 controls the drive motor 51 or when the control device 55 transmits / receives an ultrasonic signal via the ultrasonic signal processing device 59.

When an operation for starting the inspection is performed on the control device 55, the control device 55 transmits a travel control signal to the drive motor 51 to drive the drive motor 51 to rotate. Accordingly, the shaft 52 and the guide wheels 53A and 53B attached to the shaft 52 rotate, and the inspection device 50 travels in the circumferential direction of the refrigerant pipe 8. While the inspection apparatus 50 is traveling, the tips of the probes 57A, 57B, and 57C are kept in light contact with the outer periphery of the refrigerant pipe 8B.
The control device 55 controls the traveling speed of the inspection device 50 based on the information in the database.

  While the inspection device 50 is traveling, the ultrasonic signal processing device 59 transmits ultrasonic waves toward the center of the refrigerant pipe 8 via the probes 57A, 57B, and 57C under the control of the control device 55. When the transmitted ultrasonic waves are reflected at the boundaries S1, S2, and S3 shown in FIG. 3, the probes 57A, 57B, and 57C detect the reflected ultrasonic waves (hereinafter referred to as “reflected ultrasonic waves”), and The ultrasonic signal is transmitted to the ultrasonic signal processing device 59. The ultrasonic signal processing device 59 transmits the reflected ultrasonic signal to the control device 55 via the cable 60.

  When the control device 55 receives the information signal related to the reflected ultrasonic wave from the ultrasonic signal processing device 59, the control device 55 analyzes the signal, and determines the propagation time (the time taken from the transmission of the ultrasonic wave to reception) and the ultrasonic wave. A graph relating to the intensity of the sound wave is displayed on the display unit.

Here, the graph displayed on the display part of the said control apparatus 55 is explained in full detail using FIGS.
FIG. 4 is an enlarged view of the inspection device 50 that is traveling through the brazed joint 9. Here, the brazing joint 9 is in a state where the brazing material 10 is spread evenly over the entire boundary surface of the refrigerant pipes 8A and 8B (hereinafter referred to as “normal state”).

  FIG. 5A shows the propagation time of the reflected ultrasonic wave and the intensity of the ultrasonic wave detected after the probe 57A of FIG. 4 transmits the ultrasonic wave, with the horizontal axis representing the propagation time and the vertical axis representing the sound wave intensity. It is a graph. Similarly, FIG. 5B is a graph relating to the reflected ultrasound detected by the probe 57B, and FIG. 5C is a graph relating to the reflected ultrasound detected by the probe 57C. Note that these three graphs are simultaneously displayed on the display unit of the control device 55, and the graphs are appropriately changed depending on the state of the reflected ultrasonic waves.

The ultrasonic wave transmitted from the probe 57A in FIG. 4 is divided into a reflected ultrasonic wave WA1 and an ultrasonic wave WA2 propagating through the refrigerant pipe 8B at the boundary S1 between the probe 57A and the refrigerant pipe 8B. A waveform SA1 in FIG. 5A is a waveform of the reflected ultrasonic wave WA1. The ultrasonic wave WA <b> 2 propagates through the refrigerant pipe 8 </ b> B and is divided into a reflected ultrasonic wave WA <b> 3 and an ultrasonic wave WA <b> 4 propagating through the brazing material 10 at the boundary S <b> 2 between the refrigerant pipe 8 </ b> B and the brazing material 10. A waveform SA2 in FIG. 5A is a waveform of the reflected ultrasonic wave WA3. The ultrasonic wave WA4 propagates through the brazing material 10 and is divided into a reflected ultrasonic wave WA5 and an ultrasonic wave WA6 that propagates through the refrigerant pipe 8A at the boundary S3 between the brazing material 10 and the refrigerant pipe 8A. A waveform SA3 in FIG. 5A is a waveform of the reflected ultrasonic wave WA5.
Thus, in the normal state, the waveform of the reflected ultrasonic wave is as shown in FIG. 5A. Therefore, also in FIGS. 5B and 5C, the state of the brazing filler metal 10 to be inspected is in the normal state as in FIG. 5A, and the waveform of the reflected ultrasonic wave is the same as that in FIG. 5A.

  FIG. 6 is an enlarged view of the inspection apparatus 50 that is traveling through the brazed joint 9. Here, in the brazing joint 9, a cavity 63 is formed in the brazing material 10, and a portion where the brazing material 10 does not reach the refrigerant pipe 8B side of the boundary surface between the refrigerant pipe 8A and the refrigerant pipe 8B (cavity 64). ) Exists.

FIG. 7A is a graph relating to the reflected ultrasound detected by the probe 57A of FIG. Here, since the brazing filler metal 10 to be inspected by the probe 57A is in a normal state, FIG. 7A has the same waveform as FIG. 5A.
FIG. 7B is a graph relating to the reflected ultrasonic waves detected by the probe 57B of FIG. The ultrasonic wave transmitted from the probe 57B is divided into a reflected ultrasonic wave NB1 and an ultrasonic wave NB2 propagating through the refrigerant pipe 8B at the boundary S1 between the probe 57B and the refrigerant pipe 8B. A waveform TB1 in FIG. 7B is a waveform of the reflected ultrasonic wave NB1. The ultrasonic wave NB2 propagates through the refrigerant pipe 8B and is divided into a reflected ultrasonic wave NB3 and an ultrasonic wave NB4 propagating through the brazing material 10 at the boundary S2 between the refrigerant pipe 8B and the brazing material 10. A waveform TB2 in FIG. 7B is a waveform of the reflected ultrasonic wave NB3. The ultrasonic wave NB4 propagates through the brazing material 10 and further passes through the cavity 63, and is divided into a reflected ultrasonic wave NB5 and an ultrasonic wave NB6 that propagates through the brazing material 10 at the boundary S4 between the cavity 63 and the brazing material 10. A waveform TB4 in FIG. 7B is a waveform of the reflected ultrasonic wave NB5. The ultrasonic wave NB6 propagates through the brazing filler metal 10 and is divided into a reflected ultrasonic wave NB7 and an ultrasonic wave NB8 propagating through the refrigerant pipe 8A at the boundary S3 between the brazing filler metal 10 and the refrigerant pipe 8A. A waveform TB3 in FIG. 7B is a waveform of the reflected ultrasonic wave NB7.

  FIG. 7C is a graph relating to the reflected ultrasound detected by the probe 57C of FIG. The ultrasonic wave transmitted from the probe 57C is divided into a reflected ultrasonic wave NC1 and an ultrasonic wave NC2 propagating through the refrigerant pipe 8B at the boundary S1 between the probe 57C and the refrigerant pipe 8B. A waveform TC1 in FIG. 7C is a waveform of the reflected ultrasonic wave NC1. The ultrasonic wave NC2 propagates through the refrigerant pipe 8B, further passes through the cavity 64, and is divided into a reflected ultrasonic wave NC3 and an ultrasonic wave NC4 that propagates through the refrigerant pipe 8A at the boundary S3 between the cavity 64 and the refrigerant pipe 8A. A waveform TC2 in FIG. 7C is a waveform of the reflected ultrasonic wave NC3.

  Thus, when the state of the brazing filler metal 10 is normal and when it is not in a normal state (the brazing filler metal 10 has a cavity, or the brazing filler metal 10 does not reach the boundary surface between the refrigerant pipe 8A and the refrigerant pipe 8B). In the case where there is a location), there is a difference in the waveform related to the reflected ultrasound of the ultrasound transmitted by each probe. Therefore, it is possible to determine whether or not the state of the brazing material 10 is normal by referring to the graph waveform displayed on the display unit of the control device 55.

  Based on the information stored in the database, the control device 55 causes the inspection device 50 to travel one round in the circumferential direction of the refrigerant pipe 8B. Since the control device 55 continuously displays the above-described graph while the inspection device 50 makes one turn, the state of the brazing material 10 can be inspected for the entire region of the brazing joint 9 in the circumferential direction.

  As described above, according to the present embodiment, when inspecting the brazed joint 9, since the inspection is performed by ultrasonic waves without physically cutting the brazed joint 9, the time required for the inspection is reduced. Can be reduced.

  Further, according to the present embodiment, the probes 57A, 57B, and 57C are configured to be able to transmit and receive ultrasonic waves throughout the circumferential direction of the refrigerant pipe 8 at the time of inspection. The state of the brazing material 10 in the entire circumferential direction of the portion 9 can be inspected, and a highly reliable inspection result can be obtained.

  Further, according to the present embodiment, the probes 57A, 57B, and 57C are configured to be able to transmit and receive ultrasonic waves in the entire axial direction of the brazed joint 9, so that the brazed joint 9 can be performed in one inspection. Ultrasonic inspection can be performed over the entire axial direction and circumferential direction.

  In addition, according to the present embodiment, the control device 55 analyzes the reflected ultrasonic waves received by the probes 57A, 57B, and 57C at any time and displays them as a graph showing the relationship between the propagation time and the intensity of the sound waves. Test results can be easily acquired.

In addition, embodiment mentioned above shows the one aspect | mode of this invention to the last, and a deformation | transformation and application are arbitrarily possible within the scope of the present invention.
For example, in the above-described embodiment, the operator or the like determines whether or not the brazed joint 9 is in a normal state by looking at the graph displayed on the display unit of the control device 55. 55 may be determined by analyzing the data, and when it is determined that the state is not normal, the operator may be notified by an alarm or the like.

  Further, for example, in the above-described embodiment, the inspection apparatus 50 includes three probes. However, the number of probes is not limited to three, and may be appropriately determined according to the size of the brazed joint 9 and the inspection accuracy to be realized. It can be changed.

It is a figure which shows the refrigerant circuit of a refrigerator. It is sectional drawing of the brazing junction part of the refrigerant | coolant piping of a refrigerator. It is a figure which shows the state which attached the inspection apparatus which concerns on embodiment of this invention to the brazing junction part. It is a figure for demonstrating operation | movement of the inspection apparatus which concerns on this embodiment. It is a graph which shows the relationship between the propagation time of a reflected ultrasonic wave, and the intensity of a sound wave. It is a figure for demonstrating operation | movement of the inspection apparatus which concerns on this embodiment. It is a graph which shows the relationship between the propagation time of a reflected ultrasonic wave, and the intensity of a sound wave.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Refrigerator 8, 8A, 8B Refrigerant piping 9 Brazing junction part 50 Brazing defect inspection apparatus 51 Drive motor 52 Shaft 53A, 53B Guide wheel 55 Control apparatus 56 Probe attachment part 57A, 57B, 57C Probe 59 Ultrasonic signal processing apparatus 61 Mounting band

Claims (3)

Expand the end of one pipe, insert the end of the other pipe into the inner periphery of the expanded end, and braze joints in which the ends of both pipes are joined by brazing. In the brazing defect inspection device to inspect,
An inspection part capable of moving at least once around the outer periphery of the brazed joint,
The inspection parts are arranged in multiple rows in the axial direction of the brazing joints, and have a plurality of probes that contact the outside of the piping and inspect for brazing defects while transmitting and receiving ultrasonic waves. Brazing defect inspection device. The brazing defect inspection device according to claim 1, wherein the inspection unit is configured to be capable of self-running on an outer periphery of the brazed joint. The inspection unit is
A drive motor;
Guide wheels attached to both ends of the shaft of the drive motor and capable of rolling on the outer periphery of the brazed joint,
A probe attachment portion attached to the shaft and supporting a plurality of probes;
3. The brazing failure according to claim 1, wherein the inspection part can be attached to a brazed joint by connecting the shaft and the pipe with a detachable attachment band. 4. Inspection device.

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