JP2871753B2 - Endoscope device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an endoscope apparatus used for observing and inspecting internal flaws, corrosion, and the like of, for example, boilers, turbines, engines, and chemical plants.

[Problems to be Solved by the Related Art and the Invention] Conventionally, an apparatus for inspecting the inside of a pipeline has been disclosed in JP-A-56-157670.
Japanese Patent Application Publication No. JP-A-2003-115125 discloses an apparatus in which an endoscope and an eddy current flaw detector are combined.

In the above prior art, an eddy current detection coil is provided at the tip of the borescope.

However, since gas pipes and water pipes generally use ferromagnetic steel pipes, accurate inspection cannot be performed by eddy current flaw detection due to the influence of noise based on magnetic permeability. Therefore, in a precise inspection of a ferromagnetic material, for example, a sample inspection or the like is performed by cutting a part of a pipe, which requires a lot of inspection time.

The present invention has been made in view of the above circumstances, and a contact for electrical nondestructive inspection is attached to the distal end portion of an endoscope to accurately inspect corrosion and damage of a conductive structure. An object of the present invention is to provide an endoscope apparatus that can perform the operation properly and quickly.

[Means for Solving the Problems] An endoscope apparatus according to the present invention is provided with a pair of electrodes provided at a distal end portion of an insertion portion of an endoscope for passing a current to an object to be inspected, and provided between the electrodes. A pair of electrical contacts for detecting a potential due to the current, wherein the electrodes and the electrical contacts are disposed substantially on a straight line, and the objective lens is disposed substantially in the middle of the electrical contacts. Features.

[Operation] The pair of electrodes of the endoscope device configured as described above comes into contact with the object to be inspected to flow a current, and the potential of the current is detected by an electrical contact.

EXAMPLES Hereinafter, the present invention will be described specifically with reference to the drawings.

1 to 9 relate to a first embodiment of the present invention, FIGS. 1 and 2 are conceptual diagrams of the present invention, FIG. 3 is an explanatory diagram of a circuit configuration, and FIG. FIG. 5 is an overall explanatory view of the endoscope apparatus, FIG. 6 is an enlarged view of the distal end portion of the insertion portion, FIG. 7 is a sectional view taken along the line AA ′ of FIG. 6, and FIG. FIG. 9 is a sectional view taken along the line BB 'in FIG. 9, and FIG. 9 is a block diagram of the inspection apparatus.

1 to 4 conceptually explain the present invention.

FIG. 3 shows the principle of a generally known voltage ratio method. The voltage ratio method uses the contacts C1 and C2 to inspect 5
Is supplied with a constant current from the constant current circuit 7 and the voltage is measured by the contacts P1 and P2. Assuming that the resistance ρa of the inspection target 5 is and the distances between the respective contacts are r1, r2, r3, and r4, the resistance R of the inspection target 5 is obtained from the equation (2).

V = I · R (1) R = ρa / 2π (1 / r1-1 / r2 + 1 / r3-1 / r4) (2) where I: Ampere [A] V: Volt [V] r: Distance [cm] ρa: resistivity [Ω / cm] Generally, ρa increases with an increase in temperature and lattice defects, but it is rare that local changes are observed in ρa of one conductor. However, as shown in FIG. 1, a discontinuity caused by a defect 6 such as a crack causes a local and rapid change in ρa, and the resistance R of the test object 5 locally changes abruptly. In such a case, since a constant current is supplied by the contacts P1 and P2, a change in the resistance R is detected as a change in the voltage V as shown in equation (1).

Further, since the voltage V is a very small voltage, it is amplified by the DC amplifier 8, and the defective portion 6 can be detected based on the amplified voltage value.

Here, the distance between the contacts P1 and P2 in FIG. 1 is a, the plate thickness of the object 5 to be inspected is T, the depth of the flaw is d, the voltage at the flawless location is V0, and the voltage at the flawful location is V1. A flaw depth determination curve is determined in advance using V1 / V0, T / a, and d / a as parameters as shown in FIG. In actual measurement, V0 and V1 are measured to obtain d / a from the scratch depth determination curve, and since a is known, the depth d of the scratch can be obtained.

Next, a specific description will be given with reference to FIGS.

In FIG. 5, an endoscope device 11 includes an endoscope 12 and a light source device 13.
And an inspection device 14.

The endoscope 12 includes an elongated insertion section 16, and a large-diameter operation section 17 is connected to a rear end of the insertion section 16. The operation unit 17 is provided with a bending operation knob 18 on the side and an eyepiece 19 on the rear end. Further, a light guide cable 21 and a signal cable 22 extend from the side of the operation unit 17. A connector 23 is provided at the rear end of the light guide cable 21 and is detachably connected to the light source device 13. A connector 24 is provided at the rear end of the signal cable 22, and is detachably connected to the inspection device 14.

A distal end portion 26, a curved portion 27, and a flexible tube portion 28 are sequentially connected to the insertion portion 16 from the distal end side, and the operating portion 17 is connected to the rear portion of the flexible tube portion 28.

The distal end portion 26 is composed of C main bodies 29a and 29b. The C main body 29a located on the distal end side has an objective lens system 31 in the center as shown in FIG. Illumination lens systems 32a and 32b are provided. An incident end face of the image guide fiber 33 is provided behind the objective lens system 31 so that a subject image captured from the objective lens system 31 is formed. The image guide fiber 33 passes through the insertion section 16 and the operation section 17
As a result, the subject image can be visually observed in the eyepiece section 19.

Further, behind the illumination lens systems 32a and 32b, an emission end face of a light guide fiber 34 for transmitting illumination light is provided. The light guide fiber 34 reaches the light source device 13 via the insertion unit 16, the operation unit 17, and the light guide cable 21, and is supplied with illumination light output from the light source device 13.

Further, contacts P1, P2, C1, and C2 are protruded from the distal end of the C body 29a so as to sandwich the objective lens system 31 in a line in the radial direction so as to enter the visual field range 30 of the objective lens system 31. ing. Each of the contacts P1, P2, C1, C2 is provided with a pin member 37 having an elongated rod shape and a flange portion 36 provided on the outer periphery of a central portion in a circular shape. The flange portion 36 of the pin member 37 and a portion behind the flange portion 36 are slidably housed in the longitudinal direction of the insertion portion 16 in a cylindrical insulating member 38 provided in the C body 29a. The insulating member 38 is fitted in the through hole 39 of the C body 29a, and an insulating ring 43 having a through hole 42 through which the signal line 41 can be inserted is provided at the rear end of the insulating member 38.

A coil spring 44 is provided in the insulating member 38 so as to be wound around the outer periphery of the pin member 37 so as to press the flange portion 36 against the insulating ring 43.

As described above, the pin members 37 are slidable in the longitudinal direction of the insertion portion 16, and the contacts P1, P2, C1, and C2 are urged by the coil springs 44, even for the test object in the uneven state.
Can be reliably contacted.

The signal lines 41, 4 are provided at the rear end of the pin members 37, 37,.
1, ... are connected. The signal lines 41, 41,...
Is inserted through the signal line hole 46 of the C main body 29b connected to the rear part. A fixing member 47 made of, for example, a metal and formed in a cylindrical shape is internally fitted and fixed to the signal line hole 46 so as to project rearward, and further, the signal lines 41 and 41 are provided at the rear end of the fixing member 47. Are fixed by soldering or the like. The signal wires 41, 41,... Covered by the shield 48 are connected to the inspection device shown in FIG. 9 via the insertion portion 16, the operation portion 17, the signal cable 22, and the connector 24. In the figure, the inspection device 14 has signal lines 41, 41,.
Are connected to the contacts C1 and C2 through a constant current circuit 49 for supplying a constant current to the object to be inspected, and signal lines 41 and 41,
The DC amplifier 51 is connected to the contacts P1 and P2 via... And amplifies a minute voltage, and includes a voltmeter 52 for displaying the output of the DC amplifier 51.

Next, the operation of the endoscope apparatus configured as described above will be described.

A scratch depth determination curve shown in FIG. 4 is obtained in advance from samples of various thicknesses, which are formed of the same material as the inspection object. Thereafter, the insertion section 16 is inserted into the subject to be inspected, and the wound is observed from the eyepiece section 19. When measuring the depth of the flaw, the distal end of the insertion portion is moved so that the flaw is located in front of the objective lens system 31 and between the contact P1 and the contact P2, and the contact P1, P2 ,
C1 and C2 are brought into contact with the object to be inspected. Contacts P1, P2, C1,
C2 is urged in the distal direction by coil springs 44, 44,..., And is slidably provided with respect to the C body 29a. Contact the test object. In addition, contacts P1, P2, C1, C2
Since the contact state can be confirmed by an endoscopic image because it is within the visual field range 30, more accurate and quick nondestructive inspection can be performed.

A constant current is supplied to the contacts C1 and C2 from the constant current circuit 49 of the inspection device 14, and current flows between the contacts C1 and C2 through the flaw.
The contacts P1 and P2 measure the voltage between the wounds where a constant current is applied. The measured minute voltage is amplified by the DC amplifier 51 and displayed by the voltmeter 52.

V1 / V0 is calculated from the voltage value V1 obtained by the voltmeter 52 and the voltage value V0 of the place where there is no flaw measured in advance, and is calculated from the known thickness T and the distance a between the contacts P1 and P2. D / a corresponding to the obtained T / a is obtained from FIG. Distance a between contacts P1 and P2
Is known, the depth d of the scratch is determined.

According to the present embodiment, the depth of the flaw can be accurately determined by measuring the voltage value of a portion sandwiching the flaw generated in the inspection target,
Inspection can be performed quickly.

10 and 11 relate to a second embodiment of the present invention.
FIG. 11 is an overall explanatory diagram of the endoscope apparatus, and FIG. 11 is a block diagram illustrating the configuration of the inspection apparatus.

In this embodiment, an external television camera (abbreviated as an external TV camera) 54 is attached to the eyepiece 19 of the endoscope 12 of the first embodiment.
And the depth of the flaw is displayed in the endoscope image obtained by the external TV camera 54.

An external TV camera 54 is attached to the eyepiece 19 of the endoscope 12 of this embodiment.
Is detachably mounted. The external TV camera 54 is connected to a camera control unit 57 by a signal cable 56, and the camera control unit 57 is connected to an inspection device 59 by a signal cable 58.

A fixed image sensor (not shown) is provided in the external TV camera 54, and converts a subject image obtained from the endoscope 12 into an electric signal and outputs the electric signal to a camera control unit 57 via a signal cable 56. It has become. The camera control unit 57 is provided with a signal processing unit (not shown) that controls the operation of the solid-state imaging device, receives the electric signal, performs signal processing, and generates a video signal.

The inspection device 59 is connected to a monitor 62 by a signal cable 61, and displays an endoscope image on the monitor 62.

The inspection device 59 is configured as shown in FIG. In the figure, the inspection device 59 is connected to the contacts C1, C2,
A constant current circuit 49 for supplying a constant current to the object to be inspected is provided. Further, it has a DC amplifier 51 connected to the contacts P1 and P2 and amplifying a minute voltage. DC amplifier 51
Is connected to the A / D converter 63.
63 is connected to an arithmetic circuit (hereinafter abbreviated as CPU) 64. The CPU 64 has a memory 66.
For example, a flaw depth determination curve as shown in FIG. 4 is registered in advance with many parameters for V1 / V0 shown in the first embodiment. The CPU 64 performs an operation from the detected V1 / V0 to determine the flaw depth d.

The CPU 64 is connected to an image synthesizing circuit 67 to which a video signal as a subject image from the camera control unit 57 is input. The image synthesis circuit 67 converts the video signal into the CPU 64
Monitor with superimposed data indicating flaw depth d input from
Output to 62.

 Other configurations are the same as in the first embodiment.

In the present embodiment, the voltage value amplified by the DC amplifier 51 is converted into a digital signal by the A / D converter 63, and the CPU 64 performs arbitrary arithmetic processing. The CPU 64 calculates V1 / V0 from the input V1, obtains the flaw depth d from the flaw depth determination curve registered in the memory 66, and outputs it to the image synthesis circuit 67. The image synthesizing circuit 67 superimposes the flaw depth d on the video signal input from the camera control unit 57 and outputs it to the monitor 62. The monitor 62 displays the subject image and the flaw depth d.

It should be noted that the wound depth determination curve and the endoscope image may be displayed on the screen of the monitor 62.

 Other operations are the same as those of the first embodiment.

In the present embodiment, in order to display the scratch depth on the screen of the monitor 62, the observer does not calculate the scratch depth from the scratch depth judgment curve as in the first embodiment, and performs a quicker inspection. be able to.

 Other effects are the same as those of the first embodiment.

12 to 15 relate to a third embodiment of the present invention.
12 is a plan view of the distal end portion of the endoscope insertion portion, FIG. 13 is a sectional view taken along the line CC ′ of FIG. 12, FIG. 14 is a sectional view taken along the line DD ′ of FIG. 12, and FIG. FIG. 13 is a sectional view taken along the line EE 'of FIG.

In this embodiment, the endoscope 12 shown in the endoscope apparatus of the first embodiment is a side-view type endoscope.

The side-view endoscope 71 of the present embodiment includes a distal end main body 72. An illumination lens system 32 is provided on the outer peripheral wall surface of the distal end portion main body 72 on the distal end side, and an objective lens system 31 is provided on the rear side with the optical axis directed in a direction orthogonal to the longitudinal direction of the insertion section 16. ing. In addition, the contacts C1, P1, P2, and C2 are provided in the visual field direction of the objective lens system 31 in the order from the front end to the rear near the objective lens system 31. Contact P1, P2, C
Reference numerals 1 and C2 have the same structure as in the first embodiment, and are urged in the viewing direction by a coil spring 44 to be slidable.

The objective lens system 31 has 45 components in addition to the configuration of the first embodiment.
A degree prism 73 is provided, and the optical axis of the objective lens system 31 is bent in the longitudinal direction of the distal end main body 72. The illumination lens system 32 is provided with a light guide fiber 74 bent at 45 degrees in addition to the configuration of the first embodiment, so that the optical axis of the illumination lens system 32 is bent at 45 degrees.

 Other configurations and operations are the same as those of the first embodiment.

In the present embodiment, by providing the contacts P1, P2, C1, C2 in the side-viewing type endoscope in parallel with the optical axis of the objective lens system 31, the contacts P1, P2 in the side-viewing type endoscope. , C1, C2 and the inspection object can be inspected while observing the state of contact with the endoscope image, so that accurate and quick nondestructive inspection can be performed.

 Other effects are the same as those of the first embodiment.

In each of the above embodiments, the voltage ratio method (ratio of potential difference)
Has been described, but a potential distribution method (measuring the potential distribution) and an electric resistance method (measuring the electric resistance) obtained by the same configuration and principle may be used.

16 and 17 relate to a fourth embodiment of the present invention.
The figure is an overall explanatory view of the endoscope apparatus, and FIG. 17 is a cross-sectional view of the distal end portion of the endoscope insertion section.

The endoscope according to the present embodiment is an electronic endoscope 76 having a solid-state imaging device 77 at the distal end.

In the electronic endoscope 76, a universal cable 75 extends from a side of the operation unit 17. A light source connector 80 is provided at the rear end of the universal cable 75, and the light source device is provided.
13 is detachably connected. Signal cables 82 and 83 extend from the light source connector 80. The signal cable 83 is connected to the camera control unit 57, and the signal cable 83 is connected to the inspection device 59. The inspection device 59 is connected to a monitor 62 by a signal cable 61.

At the tip of the electronic endoscope 76, the contacts P1, P2, C1, C2 described in the first embodiment are provided. An optical filter 78 and a first prism 79 are provided behind the objective lens system 31. A second prism 81 formed in a wedge shape is provided on the inclined surface on the rear side of the first prism 79 with the acute angle portion directed toward the distal end. Further, a solid-state imaging device 77 is provided on the rear slope of the second prism 81. Solid-state image sensor 77
Are connected to one end of a signal line 84, 84,..., And the other end is connected to a signal processing unit (not shown) in the camera control unit 57 via the insertion unit 16, the operation unit 17, and the universal cable 75.

 Other configurations and operations are the same as those of the second embodiment.

In this embodiment, the use of the electronic endoscope 76 enables a nondestructive inspection to be performed with a clear image having a high resolution. Other effects are the same as those of the first embodiment.

FIG. 18 is a sectional view of a distal end portion of an endoscope insertion portion and a distal end adapter according to a fifth embodiment of the present invention.

In the present embodiment, the contacts P1, P2, C1, and C2 are provided on the distal end adapter attached to the distal end portion of the endoscope.

An objective lens system 31 is provided at the center of the distal end surface of the C body 29a constituting the distal end of the insertion section 16. Four contact holes 86 in the radial direction so as to sandwich the objective lens system 31,
86, ... are provided. A cylindrical insulating member 87 is fitted and fixed in each contact hole 86, and an insulating ring 88 is provided at the rear end of the insulating member 87. A front portion of the insulating member 87 forms a small-diameter portion 85, and a flange provided at the center of the outer periphery of a rod-shaped first contact 89 slidably provided in the insulating member 87 in the longitudinal direction of the insertion portion 16. The portion 91 comes into contact with the small-diameter portion 85.

A coil spring 95 is wound around the first contact point 89 behind the flange portion 91. The coil spring 95 is biased,
One end has a flange portion 91 and the other end has an insulating ring 88.
It is provided so as to abut against. Also, the first contact
One end of each of signal lines 92, 92,... Is connected to the rear end of 89, 89,. The other ends of the signal lines 92, 92,... Are connected to the inspection device 14 described in the first embodiment via the insertion section 16, the operation section 17, and the universal cable 75.

A connection ring 93 is rotatably provided on the outer peripheral wall of the C body 29a. A female thread 94 is screwed around the outer periphery of the distal end of the connection ring 93, and the outer periphery of the rear is a finger hook.

A tip adapter 96 is detachably attached to the tip of the C body 29a. A recess at the rear end of the tip adapter 96
A C main body 29a is housed in the recess 97. A female screw 98 is screwed into the rear end of the inner peripheral wall of the recess 97, and is screwed to the male screw 94 of the connection ring 93.

The tip adapter 96 is provided with an angle-of-view conversion lens system 99 such that the optical axis coincides with the objective lens system 31.
Further, four contact through holes 101, 1 are provided at positions corresponding to the first contacts 89, 89,... So as to sandwich the angle-of-view conversion lens system 99.
01,... Are provided so as to penetrate the concave portion 97 from the distal end surface of the distal end adapter 96. A cylindrical insulating member 102 is internally fitted and fixed in each contact hole 101, and an insulating ring 103 is provided at the rear end of the insulating member 102. Insulation member 102
The front part of the body forms a small-diameter part 104 and is inserted into the insulating member 102.
16 rod-shaped contacts P1 slidably provided in the longitudinal direction,
A flange portion 107 provided at the rear end of the pin member 106 constituting P2, C1, and C2 comes into contact with the small-diameter portion 104.

A coil spring 108 is wound around the pin member 106 behind the flange 107. The coil spring 108 is biased, and one end is provided so as to abut against the flange 107 and the other end is in contact with a second contact 109 adhesively fixed in the insulating ring 103. Note that the pin member 106, the coil spring 108, and the second contact point 109 are in an electrically conductive state.

 Other configurations are the same as in the first embodiment.

In the endoscope apparatus configured as described above, when the distal end adapter 96 is attached to the distal end portion of the endoscope, the C body 29 is placed in the concave portion 97.
a is inserted, the connection ring 93 is rotated, and the male screw portion 94 is screwed into the female screw portion 98. When the tip adapter 96 is connected to the C body 29a, the first contacts 89, 89,.
9, 109, ... contact. Since the first contacts 89, 89,... Are urged by the coil spring 95, the first contacts 89, 89,.
. And the second contacts 109, 109,... Are reliably connected.

After the tip adapter 96 is attached as described above, the tip adapter 96 is inserted into the object to be inspected.

 Hereinafter, the operation is the same as that described in the first embodiment.

Although the direct-view type distal end adapter 96 is shown in the present embodiment, for example, a side-view adapter may be provided detachably.

As described above, since the distal adapter having the contact is detachably provided, the direct-view adapter and the side-view adapter can be freely exchanged, so that an optimal nondestructive inspection can be performed according to the inspection object.

In addition, a contact using a voltage ratio method may be provided in a travel assisting tool that is detachably attached to the distal end portion of the endoscope.

[Effects of the Invention] As described above, according to the present invention, since the contact for the electric non-destructive inspection is attached to the distal end of the endoscope, the inspection of the corrosion and the flaw of the conductive structure can be performed. It can be performed accurately and quickly, and when detecting the above-mentioned corrosion and scratches,
This can be simultaneously magnified and observed with the objective lens of the endoscope.

[Brief description of the drawings]

FIGS. 1 to 9 relate to a first embodiment of the present invention.
FIGS. 2 and 3 are conceptual diagrams of the present invention, FIG. 3 is an explanatory diagram of a circuit configuration, FIG. 4 is a graph of a wound depth determination curve, FIG. 5 is an overall explanatory diagram of an endoscope apparatus, FIG. Is an enlarged view of the tip of the insertion section,
7 is a sectional view taken along the line AA 'of FIG. 6, FIG. 8 is a sectional view taken along the line BB' of FIG. 6, FIG. 9 is a block diagram of the inspection apparatus, and FIGS. According to the second embodiment of the present invention,
10 is an overall explanatory view of the endoscope apparatus, FIG. 11 is a block diagram for explaining the configuration of the inspection apparatus, FIGS. 12 to 15 relate to a third embodiment of the present invention, and FIG. FIG. 13 is a sectional view taken along the line CC ′ of FIG. 12, FIG. 13 is a sectional view taken along the line DD ′ of FIG. 12, and FIG. E-
16 and 17 relate to a fourth embodiment of the present invention. FIG. 16 is an overall explanatory view of the endoscope apparatus, and FIG. 17 is a cross section of the distal end portion of the endoscope insertion portion. FIG. 18 is a sectional view of a distal end portion of an endoscope insertion portion and a distal end adapter according to a fifth embodiment of the present invention. 5 ... inspected object, 6 ... defective part 7 ... constant current circuit, 8 ... DC amplifier 12 ... endoscope, 30 ... field of view 31 ... objective lens system P1, P2, C1, C2 ... … Contact

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01N 27/00-27/24 G02B 23/24-23/26

Claims (1)

(57) [Claims] 1. A pair of electrodes provided at the distal end of an insertion portion of an endoscope for passing a current through an object to be inspected, and a pair of electric electrodes provided between the electrodes and detecting a potential caused by the current. An endoscope apparatus comprising: an electrical contact; and the electrode and the electrical contact are disposed substantially on a straight line, and an objective lens is disposed substantially in the middle of the electrical contact.