JPH11304771A - Surveying device for small-diameter tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surveying device for small-diameter tube which can easily, precisely, and stably make ultrasonic measurement over wide ranges in the peripheral and axial directions of a small-diameter tube through water or grease, by using an ultrasonic probe and laying a flexible thin film on the outer periphery of the tube. SOLUTION: A surveying device for small-diameter tube is composed of a tank containing water or grease 19, a probe holder 11 which is positioned inside or outside the tank and provided with a moving means, an ultrasonic probe 12 attached to the holder 11, an ultrasonic measuring means which detects the presence/absence of scales and the state of the wall of a small-diameter tube from the time lag between the transmission of ultrasonic waves front the probe 12 and the reception of echoes by means of the probe 12 through the water and grease 19, a flexible thin film 16 which is provided to the guide section 15 for object to be inspected of the tank and made of rubber, etc., and a positive or negative pressure imparting means which deforms the thin film 16 in accordance with the outer periphery of an object 17 to be inspected front the guide section 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-diameter pipe detecting apparatus for detecting the presence or absence of a scale attached to a small-diameter pipe of about 1 to 4 inches in a heat transfer pipe or other pipe of a boiler or the like in a factory facility, and the state of a pipe wall. About.

[0002]

2. Description of the Related Art Conventionally, an ultrasonic probe has been known as a thickness gauge for a tube using ultrasonic waves. In this method, water or grease is interposed between the object to be measured and the ultrasonic probe, ultrasonic waves are incident, image processing is performed based on the time difference from the reflected echo, and the thickness and scale of the tube are reduced. The purpose is to detect the presence or absence and the state of the pipe wall.

[0003] For example, when measuring the steam oxidation scale adhering to the inside of a tube, there is an apparatus using a broadband type vertical probe having a frequency of about 15 MHz. The time difference between the transmission of the ultrasonic wave and the echo signal is converted into an analog signal using a D / A converter and input to a signal discriminating circuit for image processing.
The boundary between the base material and the scale can be identified.

A method of observing a large-diameter tube by inserting a camera inside the tube has also been adopted.

[0005]

Among the conventional examples described above, in the method using an ultrasonic probe, grease is used between the ultrasonic probe and the tube to extend in the pipe circumferential direction and in the axial direction of the pipe. It is possible to move the ultrasonic probe and acquire the data of the transmitted and echo signals. However, for small diameter tubes of 4 inches or less,
Since the outer periphery of the tube is not flat, it is difficult to inspect with water interposed therebetween, and this cannot be used immediately.

In a factory, it is necessary to control wall thinning due to high-temperature oxidation and corrosion in order to control the life of heat transfer tubes such as boilers. It was necessary for a skilled person to directly perform manual operation and measurement using an ultrasonic probe from the outside. However, in the case of a small-diameter pipe, there was no other way but to rely on a manual operation by a skilled person to measure the situation in the pipe in a small radius, and continuous and stable measurement was difficult.

[0007] In addition, there is no method other than manual inspection by inserting a camera into a tube, except for manual operation by a skilled person, and the thickness of the scale is locally changed. Was. The object of the present invention is to solve the above-mentioned difficulties, transmit water or grease from an ultrasonic probe, and transmit the same, and as a device for measuring the presence or absence of a pipe wall state or scale by the time difference of reception by the echo,
It is an object of the present invention to provide a small-diameter tube exploration device which is capable of easily and precisely and stably measuring an ultrasonic wave over a wide range in the tube circumference and the tube axis direction by providing a flexible thin film along the outer periphery of the tube.

[0008]

According to a first aspect of the present invention, a tank containing water or grease is provided.
Provided inside or outside this tank, a probe holder provided with a moving means, an ultrasonic probe attached to the probe holder, and from the ultrasonic probe through the water or grease, transmitting and receiving by echo. Ultrasonic measurement means for exploring the presence or absence of scale and the state of the tube wall by the time difference of the above, a rubber or other flexible thin film provided on the test object guide portion of the tank, and the flexible thin film A small-diameter pipe exploring apparatus comprising: a positive pressure or negative pressure applying means for deforming the guide along the outer periphery of the test object.

In the second invention, an adapter for positioning the test object is detachably provided in accordance with the end of the test object guide portion. In the third invention, the ultrasonic probe is mounted on the probe holder so as to be adjustable in position, and the probe holder is provided so as to be intermittently or continuously movable along the circumferential direction and the axial direction by the arched guide.

In the fourth invention, a guide plate is provided on the test object guide portion and guides the deformation of the flexible thin film at the free edge.

[0011]

According to the first aspect of the present invention, since the ultrasonic probe is attached to the probe holder provided with the moving means, the ultrasonic probe can be adjusted to be at an attaching position at an appropriate distance from the small-diameter tube. It is free to move in the direction of the tube axis, and stable measurement can be performed over a wide range around the small diameter tube (tube) of the test object.

Also, if an ultrasonic probe is attached to a large diameter of the small diameter pipes, the measurement can be performed as it is for small diameter pipes having different diameters within the allowable range of measurement. The outside can be adjusted by changing the mounting position. Since the transmission of the ultrasonic wave from the ultrasonic probe and the reception by the echo are performed through water or grease, the measurement can be performed accurately without disturbing the incidence of the ultrasonic wave. If image processing is performed based on the data obtained by the time difference between the transmission and the reception, the presence or absence of the scale and the state of the tube wall can be accurately measured.

[0013] The probe holder can be provided in the tank, but need not necessarily be in the tank. It may be driven by a coupling mechanism or other device from outside the position close to the tank. A test object guide section is provided in the tank, and the flexible thin film is deformed by the positive pressure or negative pressure applying means and can be brought into close contact with the outer periphery of the small-diameter pipe of the test object. The flexible thin film does not float or wrinkle, and can be measured quickly over a wide range in the outer periphery and in the axial direction.

As described above, the flexible thin film comes into close contact with the test object only when pressure is applied, and when there is no pressure, the flexible thin film contracts and does not touch the outer periphery of the tube. Therefore, the entire apparatus can move freely, and can move in the pipe axis direction along the pipe circumferential direction or at regular intervals. Furthermore, if the entire configuration of the probe holder, the ultrasonic probe, and the like is compactly loaded in the tank, the device can be moved and transported as a handy search device, and measurement can be easily performed.

In the second invention, the positioning adapter is provided in accordance with the end of the test object guide portion of the tank.
Since the apparatus is easy to follow along the outer circumference of the pipe of the test object and the adapter is detachable, it can be replaced according to the diameter of the small-diameter pipe, and can be easily set concentrically with the pipe. In the third invention,
The ultrasonic probe is attached to the probe holder so that its position can be adjusted, it can be moved according to the diameter of the small-diameter tube, and the measurement position in the circumferential direction can be freely selected along the arched guide.
It can also move in the tube axis direction. It can be moved intermittently or continuously in both the circumferential direction and the pipe axis direction, and data on each peripheral portion can be obtained promptly and uniformly, and data over a wide range of small diameter pipes can be obtained stably.

Further, if the ultrasonic probe is attached to the probe holder in accordance with the large dimensions of the tubes that can be measured, the tubes within the allowable measurement range of the probe can be measured without adjustment, and can be measured outside the allowable measurement range. Adjustment of the probe mounting position can be easily adjusted for this tube.
In the fourth invention, by providing a guide plate that facilitates the close contact of the flexible thin film along the outer periphery of the test object, the flexible thin film just floats along the outer periphery of the tube in response to pressure,
Deformation and adhesion can be achieved without wrinkles.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The exploration apparatus of the present invention can be constituted by a handy tank in which the whole image is a cube or a rectangular parallelepiped, and can easily follow the test object by providing a positioning adapter. The positioning adapter can be replaced with an appropriate one according to the diameter of the small-diameter tube of the test object, and is set so that the ultrasonic probe can be moved in an arc shape through an arched guide concentric with the center of the small-diameter tube. .

Further, a flexible thin film is provided on the test object guide portion of the tank, and is brought into close contact with the outer periphery of the small-diameter pipe of the test object when pressure is applied.
Ultrasonic waves can be transmitted and echoes can be received over a wide area through water or grease. By applying a positive pressure to the flexible thin film provided on the test object guide portion or by applying a negative pressure to the outside of the flexible thin film, the flexible thin film adheres to the small-diameter tube. Measurement can be performed stably. The device is free to move because the flexible membrane returns to its original shape when the pressure is removed.

Since the ultrasonic probe is attached to a probe holder provided with a moving means inside or outside the tank, it can be moved in the circumferential direction of the tube or in the direction of the tube axis. If the mounting position is shifted, it can be applied to small diameter pipes with different diameters. The ultrasonic probe can be moved intermittently or continuously in the direction of the tube circumference and in the direction of the tube axis, and can be easily and stably measured over a wide range by repeating the entire circumference of the tube and repetition at a fixed length.

In the circumferential direction of the tube, the entire circumference can be measured three times by moving the apparatus every 120 degrees, for example. If the size of the tank is about 200 mm square, a compact and portable exploration device can be provided.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details will be described below with reference to the drawings shown as embodiments. In FIG. 1, reference numeral 1 denotes an example of a small-diameter tube exploration apparatus, 2 denotes a holding portion made of rubber or other flexible thin film, 3 denotes a tank containing water or grease and is provided with an ultrasonic probe, and 4 denotes a positioning. The small-diameter pipe search device 1 is guided by the adapter for use so as to match the small-diameter pipe of the test object. 5 is a handle, which is handy.

FIG. 2 shows another embodiment, in which 6 is a pressing portion made of rubber or other flexible thin film, 7 is a tank containing water or grease and provided with an ultrasonic probe, and 8 is a driving unit, The probe is movable. Numeral 9 denotes a positioning adapter, which can easily adjust the small-diameter pipe search device 1 to the outer circumference of the small-diameter pipe of the test object. Positioning adapter 4,
9 can be replaced according to the size of the test object, and may be made of a ferromagnetic material or an electromagnet to be attached to a small-diameter tube as a material. A nonmagnetic material may be used to mechanically contact the small-diameter pipe. 1
0 is a handle.

FIGS. 3 and 4 are perspective views showing an example of a moving mechanism provided in the tank 3 containing water or grease.
1 is a probe holder, and 12 is an ultrasonic probe.
The ultrasonic probe 12 is attached to the probe holder 11 so that the position can be adjusted (moved in the axial direction). The probe holder 11 is attached to an arched guide 13 and is movable on a circumference by a motor or the like.

In the illustrated example, only one probe holder 11 is mounted. However, if two probe holders 11 are provided and driven at the same time, the time required for one probe to move to the entire arch-shaped guide 13 and to measure it is reduced. Compared with this, it is possible to perform a short half-time measurement. For the movement in the tube axis direction, an inverted U-shaped frame is used in the illustrated example, but the invention is not limited to this. Any configuration may be used as long as it is a mechanism that converts a rotary motion into a linear motion.

The arch type guide 13 is continuously or intermittently moved in the pipe axis direction by a moving mechanism 14 including a motor, a screw shaft, a pinion gear, and a mechanism for converting a rotary motion into a linear motion as illustrated in FIG. It is set to be possible. Although these moving mechanisms 14 can be provided in the tank, they may be provided in the drive unit 8 shown in FIG. Although the motor and the pinion gear shown in FIG. 3 are shown projecting from the tank, they are actually built in a case to facilitate operation and handling.

In FIG. 4, reference numeral 15 denotes an object guide section.
A small-diameter tube as a test object is a space that is guided below the flexible thin film 16 by the positioning adapter 4. The rubber or other flexible thin film 16 is usually a flat film as shown by a dashed line as an elastic thin film or a thin plate, but it is covered when a positive pressure is applied from inside the tank or a negative pressure is applied to the outside. The specimen 17 is deformed so as to be in close contact with the outer periphery of the small-diameter tube (tube) 17 (see FIGS. 4 and 5), and returns to its original state when pressure is released. A guide plate 18 is attached to the case, and when the flexible thin film 16 is deformed by pressure, it is simultaneously deformed and guided so that the flexible thin film closely adheres to a wide area on the outer periphery of the small diameter pipe. In the illustrated example, the guide plates 18 are provided at both end edges of the test object guide portion. However, only one guide plate may be provided.

In FIGS. 6 and 7, when the compressed air 21 is filled in the air bag 20 above the water or grease 19 in the tank (FIG. 6) as the positive pressure applying means, the water pressure in the water 19 in the tank is increased. FIG. 7 shows a case in which the call is applied. In addition, a negative pressure may be applied around the small diameter pipe, and these constitute the positive or negative pressure applying means 22. FIG. 4 shows the case where pressure is applied, and FIGS. 6 and 7 show the case where pressure is not applied to the flexible thin film 16.

In order to detect the state of the tube wall and the presence or absence of scale by the ultrasonic probe 12, image processing is performed by a computer based on the time difference between the transmission from the ultrasonic probe 12 and the reception by the echo as shown in FIG. Ultrasonic measuring means 23 capable of displaying is used. When the data appearing on the scope is compared at points A, B, and C of the small-diameter tube 17, the state of the tube wall and the presence or absence of the scale become clear.

[0029]

According to the present invention, since a rubber or other flexible thin film is brought into close contact with the outer periphery of the small-diameter tube of the test object, it can be measured with an ultrasonic probe via water or grease.
There was no disturbance in the incidence, and precise measurement became possible. In addition, image processing is performed based on the time difference between transmission and reception by the ultrasonic probe, and the state of the tube wall of the test object and the presence or absence of scale can be clearly measured.

By the moving means provided on the probe holder, the mounting position of the ultrasonic probe can be adjusted, it is easy to adjust to the diameter of the small-diameter pipe, and it can be moved in the pipe circumferential direction or the pipe axis direction. Therefore, it is possible to measure all over the entire tube. Since the flexible thin film is brought into close contact with the test object by the positive or negative pressure applying means, the measurement operation is easy, and the diameter of the small diameter pipe is reduced by using a positioning adapter provided in the tank. Different ones can be easily set.

By providing a guide plate that facilitates the close contact of the flexible thin film along the outer periphery of the test object, the flexible thin film can be adhered to the small-diameter tube without any gap, and the ultrasonic waves are not disturbed. If the whole is divided into a tank or a tank and a mechanism, it can be used as a compact and portable measuring instrument, and its application range is wide.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an overall image of the present invention.

FIG. 2 is a perspective view showing another embodiment of the overall image of the present invention.

FIG. 3 is a perspective view showing an embodiment of the moving mechanism, which is partially cut away.

FIG. 4 is a front view showing an embodiment of a probe holder.

FIG. 5 is a sectional view showing a state where a flexible thin film is pressed.

FIG. 6 is an explanatory view of an embodiment of a positive pressure applying means for a flexible thin film.

FIG. 7 is an explanatory view of another embodiment of a positive pressure applying means for a flexible thin film.

FIG. 8 is an explanatory diagram showing an example of image processing of measurement by an ultrasonic probe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Exploration apparatus for small diameter pipes 2 Rubber or other flexible thin films 3, 7 Tank 4, 9 Positioning adapter 11 Probe holder 12 Ultrasonic probe 13 Arch type guide 14 Moving mechanism 15 Test object guide section 16 Flexible thin film 17 Small diameter Tube (tube) 18 Guide plate 19 Water or grease 22 Positive or negative pressure applying means 23 Ultrasonic measuring means

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[Procedure amendment]

[Submission date] April 24, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Explanation of sign

[Correction method] Change

[Correction contents]

[Description of Signs] 1 Exploration device for small diameter pipe 3, 7 Tank 4, 9 Positioning adapter 11 Probe holder 12 Ultrasonic probe 14 Moving mechanism 15 Test object guide section 16 Flexible thin film 17 Small diameter pipe (tube) 18 Guide plate 19 Water or grease 22 Positive or negative pressure applying means 23 Ultrasonic measuring means

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

[Procedure amendment 3]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

FIG. 3

Claims (4)

[Claims] 1. A tank containing water or grease, a probe holder provided inside or outside the tank and provided with moving means, an ultrasonic probe attached to the probe holder, Ultrasonic measurement means for exploring the presence or absence of a scale and the state of the tube wall by the time difference between the transmission and the reception by the echo through water or grease, and rubber and other flexible members provided in the test object guide portion of the tank A small-diameter pipe exploring apparatus, comprising: a flexible thin film; and positive or negative pressure applying means for deforming the flexible thin film from the test object guide portion along the outer periphery of the test object. 2. The apparatus according to claim 1, wherein an adapter for positioning the test object is detachably provided in accordance with an end of the test object guide portion.
An exploration device for a small diameter pipe as described in the above. 3. The ultrasonic probe according to claim 1, wherein the ultrasonic probe is mounted on the probe holder so as to be adjustable in position, and the probe holder is intermittently or continuously movable along the circumferential direction and the axial direction by an arched guide. Exploration equipment for small diameter pipes. 4. A guide plate provided at a guide portion of a test object and guiding a deformation of a flexible thin film at a free edge.
4. The exploration device for small diameter pipes according to 2 or 3.