KR20000014485A - Apparatus for measuring pipe corrosion of heat exchanger using supersonic - Google Patents

Abstract

PURPOSE: A corrosion measuring device of a heat exchanger pipe is provided to enhance reliability of testing result and prevent the equipment from breaking down caused by corrosion of the pipe. CONSTITUTION: The device comprises a supersonic detecting head, a supersonic detector, a data input/storing section, and an analyzer. The head successively transmits supersonic toward an inner wall of the pipe at each position and receives the supersonic to convert a supersonic signal thereof into an electric signal. The detector is coupled to the head and displays the converted electric signal by a display device. The section is coupled to the detector, converts the electric signal into a digital signal, and inputs or revises design of a measured pipe. The analyzer analyzes a program including corrosion degree and remaining life of the pipe.

Description

APPARATUS FOR INSPECTING CORROSION IN THE HEATEXCHANGER TUBE USING ULTRASONICS

The present invention relates to an apparatus for measuring the corrosion of the inner surface of the tube of the heat exchanger, and more particularly to an apparatus for measuring and analyzing the corrosion of the inner wall of the tube using an ultrasonic flaw detector.

Heat exchangers, which are used for the cooling, condensation, heating, and evaporation of fluids in oil, chemical, and general chemical industries, are multi-tube heat exchangers and one inner tube is inserted into one outer tube in a concentric manner. Double tube heat exchanger for exchanging fluid in a tube and exchanging heat with each other, single tube heat exchanger for flowing a single tube into a coiled or sanded tube and heating and cooling it outside of the tube through a heating or cooling device , And air-cooled heat exchangers.

Among them, the multi-tube heat exchanger is applicable to all applications such as heating, cooling, evaporation, and condensation from low pressure to high pressure and low temperature to high temperature, and is widely used because of its high heat transfer efficiency and high reliability.

Since the multi-tube heat exchanger is in frictional contact with the fluid at high temperature and high pressure, the inner wall of the pipe easily corrodes, causing various problems such as equipment failure. Therefore, the pipes of the heat exchanger are periodically checked for corrosion or corrosion. These heat exchanger tubes are usually small in diameter, which makes it very difficult to check the corrosion of the inner wall by inserting an inspection device into the tube. Therefore, in the case of inspecting the corrosion of the tube of the heat exchanger, a sampling cut inspection method of sampling and cutting the sample after inspection has been mainly used.

However, this sampling inspection method has a problem that the number of samples is limited and an error occurs in the inspection value depending on the sampling position and the sample linker. In addition, the heat exchanger tube should be periodically inspected, and at this time, there is a problem of lowering the thermal efficiency of the heat exchanger by exposing the tube.

Accordingly, an object of the present invention is to provide a non-destructive pipe corrosion measuring apparatus using ultrasonic waves that solves the above problems with the sampling cut inspection method used to measure internal corrosion of heat exchanger tubes.

In addition, an object of the present invention is to provide an apparatus for determining the remaining life of a tube by selecting the appropriate sampling water by an experimental formula and extreme statistics of the pipe corrosion measurement result.

The present invention for achieving the above object is inserted into the tube of the heat exchanger and the ultrasonic wave to transmit and receive the ultrasonic wave toward the inner wall of the tube at each position while rotating in the longitudinal direction of the tube to convert the ultrasonic signal into an electrical signal Ultrasonic flaw detection unit, the ultrasonic flaw detection unit is connected to the ultrasonic flaw detection head by a coaxial cable to display an electrical signal transmitted from the ultrasonic flaw detection head unit, and a data input / storage unit for receiving the electrical signal from the ultrasonic flaw detector and convert it into a digital signal And an analysis device for analyzing the corrosion degree and the remaining life of the pipe by analyzing the data input / storage data by an extreme statistical analysis method.

According to the present invention configured as described above, the degree of corrosion generated inside the tube of the heat exchanger, which is difficult to measure the degree of corrosion, can be automatically or manually inspected without leaving the tube to automatically determine the degree of deterioration and the remaining life of the tube. It is.

1 is a view schematically showing the overall configuration of a heat exchanger tube corrosion measurement apparatus according to the present invention,

Figure 2 is a cross-sectional view showing the configuration of the ultrasonic flaw detection head portion of the heat exchanger tube corrosion measuring apparatus according to the present invention,

3 is a view showing the flaw detection range of the ultrasonic flaw detection head according to the present invention,

4 is an example of a graph relating to the corrosion state of the tube displayed on the ultrasonic flaw detection by the ultrasonic flaw detection head according to the present invention,

(a) is a graph showing the flaw detection signal with respect to the distance traveled by the flaw detection head portion,

(b) is a graph showing the result of converting the graph of FIG. 4 (a) into the distance to the inner wall of the tube to be measured measured by each ultrasonic pulse together with the distance to the calibration block.

※ Explanation of code for main part of drawing

E: heat exchanger T: tube

10; Ultrasonic Scanning Head Part 11: Casing

12: transducer 13: centering means

13a; support tube 13b: cushioning material

14 impeller 15 bearing

16: mirror 17: cap

18: fin 19; Coaxial cable

B: Ultrasonic beam C: Calibration block

20: Ultrasonic flaw detector Design specification: Display

30: data input / storage unit 40: data analysis device

P: pump

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 schematically shows the overall configuration of the heat exchanger tube corrosion measuring apparatus according to the present invention.

As shown in FIG. 1, the heat exchanger tube corrosion measuring apparatus according to the present invention is a water immersion ultrasonic flaw detector using water as a contact medium, and the contact medium inside the tube T of the heat exchanger E to be measured. It includes an ultrasonic flaw detection head unit 10 for transmitting an ultrasonic signal toward the inner wall of the measurement tube (T) while receiving water, and then receiving the ultrasonic signal and converting the received ultrasonic signal into an electrical signal.

The ultrasonic flaw detection head unit 10 includes a casing 11 through which water flows and a casing 11 to be kept concentric with the tube T within the tube T. A centering means (13) for holding T) and a probe (12) installed in the casing 11 in the direction of the casing central axis.

Here, as shown in FIG. 2, the centering means 13 is formed of an engineering plastic support tube 13a whose outer diameter is slightly smaller than the inner diameter of the tube to be measured T, and the outer circumference of the support tube 13a The cushioning material 13b made of the same material as the Velcro tape is coated to support the measurement tube T without any gap between the measurement tube T and the casing 11 according to the change in the inner diameter of the measurement tube T. have.

On the other hand, the centering means 13 is not limited to the above structure, and any structure may be used as long as the centering means 13 supports the casing 11 concentrically with respect to the measurement tube T. For example, the support tube 13a gradually decreases in diameter toward the rear in the longitudinal direction so that the support tube 13a is fixed to the outer circumferential wall of the casing 11 only at the rear end thereof. The front end large diameter portion of 13a is elastically retracted to be in close contact with the inner wall of the measurement tube T to support the casing 11 concentrically with the measurement tube T.

The transducer 12 transmits an ultrasonic beam B along the central axis direction of the casing 11 or receives an ultrasonic beam B returned along the central axis direction of the casing 11. The ultrasound beam (B) installed inside the transducer is to be converted into an electrical signal.

The water filtered through the filter passes through the inside of the casing 11 by the pump P and flows into the tube T under measurement. The casing 11 is provided with a transfer device (not shown) at the rear end to transfer the transducer 12 installed therein in the front-rear direction while advancing back and forth by the transfer device. This feeder is connected to the servo motor with forward and reverse rotation of the casing 11 by screwing. This servo motor is connected to the encoder, and when the servo motor rotates by the predetermined speed by the encoder signal, the servo motor and screw The combined casing 11 is to be moved back and forth by a predetermined distance.

The transfer device can be moved back and forth with the motor as described above, but is not limited to this configuration, and can be of various configurations such as manually moving the casing forward and backward.

In addition, the turbine type impeller 14 is installed at the front end of the casing 11 so as to be free to rotate through the bearing 15, and the impeller 14 is installed in a concentric manner with the casing 11 and the casing 11. (11) It rotates by the force of water which penetrates inside and is supplied to the inside of the pipe T.

The impeller 14 reflects the ultrasonic beam B transmitted from the probe 12 toward the inner wall of the tube T, and reflects the ultrasonic beam B reflected from the inner wall of the tube T again. The mirror 16 which sends to the transducer 12 is provided.

The reflecting surface of the mirror 16 is inclined at an angle of 45 degrees with respect to the central axis of the casing 11. Therefore, the ultrasonic beam B emitted from the transducer 12 is reflected at 90 degrees by the mirror 16 and reflected on the tube T, and then reflected at 90 degrees by the mirror 16 to the transducer 12. It will return.

Therefore, the casing 11 is retracted from the inside of the tube (T) by the transfer device and at the same time the impeller 14 provided at the tip of the casing 11 rotates the mirror 16 in the axial direction. Ultrasonic waves transmitted from the transducer 12 are to detect the inner wall of the tube T evenly while drawing a spiral trajectory, as shown in FIG.

The present invention includes an ultrasonic flaw detector 20 connected to the ultrasonic flaw detector head 10. The ultrasonic flaw detector 20 is configured to show the corrosion degree of the tube T to be measured through a display such as a monitor based on the electrical signal obtained by converting the ultrasonic signal from the transducer of the transducer 12.

In addition, a cap 17 is screwed to the front end of the casing 11 to prevent the mirror 16 from being separated from the casing 11, and the mirror 17 is connected to the front end of the casing 11. Fins 18 are provided to extend in the lengthwise direction of (16).

The pin 18 rotates together with the mirror 16 and reflects each ultrasonic pulse of ultrasonic waves radiated toward the inner wall of the tube T to be mirrored to the mirror 16. Thus, the ultrasonic waves reflected by the fin 18 are It enters the probe 12 and is input as a pin signal to the ultrasonic probe 20 through the coaxial cable 19 and displayed as shown in a of FIG.

That is, each pulse of the ultrasonic wave transmitted from the transducer 12 is reflected by the mirror 16 which rotates together with the impeller, and the pin 18 first transmits the ultrasonic wave pulse immediately before reaching the tube T to be measured. The reception is reflected and displayed on the graph of the ultrasonic flaw detector 20 as a pin signal such as a. And the ultrasonic flaw detection unit 20 counts the number of revolutions of the impeller 14 by the pin signal, and the sine figure, which is a measured value of the measured tube T spirally inspected using the counted impeller number of revolutions ( 4 (a) is transformed into a straight line such as b of FIG. 4 (b).

That is, an example of a graph of the raw signal received by the transducer 12 is shown in FIG. 4 (a). As shown in FIG. 4 (a), the signal value for the ultrasonic pulse reflected on the inner wall of the tube T to be drawn is a sine curve equal to b, and the ultrasonic pulse received by the pin 18 is a mirror. The bar graph b per rotation of 16 is displayed. The sharp part of the sine curve indicates corrosion inside the tube (T).

The data input / storage unit 30 converts the signal received from the ultrasonic detector 20 into a graph of the measured tube diameter (vertical axis value) for each ultrasonic pulse (horizontal axis value). An analysis graph is shown in FIG. 4 (b).

As shown in Fig. 4 (b), the signal value a received by the pin 18 is shown as a rod in the vertical direction in Fig. 4 (a), and the signal value of the pin 18 is shown. Using (a), the sine curve (b) in the graph of FIG. 4 (a) is converted into a straight line (b) that is developed in the horizontal direction and displayed as shown in FIG. 4 (b). The horizontal axis value of the horizontal straight line (a in FIG. 4 (b)) with respect to the signal value of this pin 18 is used as the reference diameter of the tube T to be measured.

In addition, the straight line in FIG. 4 (b) serves as a reference for comparative measurement close to the specification of the tube to be measured, and as a difference between the straight line and the measurement result of the tube to be measured T ), You can see the amount of corrosion.

In addition, the present invention includes a data input / storage unit 30 is connected to the ultrasonic flaw detection unit (20). The data input / storage unit 30 may convert the electrical signal of the ultrasonic detector 20 into a digital signal and simultaneously input or modify various parameters of the tube under measurement such as the material or dimensions of the tube T under measurement. The data input / storage unit 30 is suitable for a portable computer that can be installed and used by moving several places.

In addition, the present invention receives the digital signal converted in the data input / storage unit 30 and the data of the design specifications of the tube to be measured to determine the degree of corrosion of the tube (T) by a program according to the extreme analysis method, A data analysis device 40 for determining the remaining life of T) is included.

On the other hand, the present invention uses a calibration block to measure the corrosion of the tube to be measured (T).

That is, the calibration block is formed in advance in the inner diameter of the tube corresponding to the inner diameter of the tube to be measured, and a predetermined step corresponding to the corrosion groove is formed in advance, and then ultrasonically inspects the calibration block before the tube is inspected. The result value is set as a reference value for the result value detected by the actual measurement tube T and stored in the data input / storage unit.

In addition, the ultrasonic flaw detection head part 10 of the present invention has a certain length, and the ultrasonic flaw detection head part 10 must be supported concentrically in the measurement tube T so that the ultrasonic flaw detection head can be performed. Measurement is impossible at the inlet tip of the tube T under which the portion 10 is not fully supported.

In order to solve this problem, the present invention includes a guide tube for measuring the inlet tip of the tube (T). When the ultrasonic scanning head portion 10 is inserted into the inlet tip of the measuring tube T while the guide tube is inserted into the tip of the measuring tube T, the guide tube is connected to the ultrasonic scanning head portion 10. Since it supports the rear end, it is possible to measure even the inlet end of the measurement tube (T).

Hereinafter, the process of measuring the tube corrosion of the heat exchanger using the apparatus of the present invention will be described.

First, if there is a corrosion product or a precipitate in the tube of the heat exchanger (E) to be measured, the ultrasonic wave will interfere with the progress and cause a false indication. Therefore, the corrosion product in the tube is mechanically or physically removed.

That is, one end of the heat exchanger (E) tube is opened, and then a rotating brush is inserted into the inside of the tube, while the rotary tool is rotated and pushed into the tube to remove deposits and rust. At this time, by using a so-called water jet method that sprays high pressure water into the tube, the tube can be washed effectively.

Then, the ultrasonic flaw detection head unit 10 according to the present invention is inserted into the calibration block C to input / store the ultrasonic signal for the stepped portion (large inner diameter portion) as a reference value to the data input / storage unit.

Then, the ultrasonic flaw detection head unit 10 according to the present invention is inserted into the measurement tube T. In this state, the ultrasonic probe 12 is operated while pumping water into the casing 11 of the ultrasonic flaw detection head 10.

At this time, bubbles are generated in the water flowing inside the measurement tube (T), and when the ultrasonic waves reach and scatter or reflect the bubbles, false signals are sent. In this case, in the present invention, by blocking the one end of the tube to be measured (T) and supplying water to increase the pressure of the supply water to suppress the occurrence of bubbles, or by supplying water in the tube (T) little by little to the inside of the tube Pressure is applied to remove bubbles.

The ultrasonic beam B transmitted from the ultrasonic probe 12 is continuously sent along the circumferential direction of the inner wall of the tube T by the mirror 16 rotating by the impeller 14 at the tip of the casing 11. The ultrasonic beam B is primarily reflected by the pin 18 extending from the cap 17 and passed through the mirror 16 to determine the value for the reference inner diameter of the tube T to be measured. In addition, it is reflected from the inner wall of the tube T to be reflected and reflected by the mirror 16 and received by the probe 12 as a corrosion signal which is a measurement signal of the tube T to be measured.

The ultrasonic beam B received by the transducer 12 is converted into an electrical signal by a transducer and then sent to the ultrasonic flaw detector 20 for display on the display.

Then, the data input / storage unit 30 converts the electrical signal sent from the ultrasonic detector 20 into a digital signal at the signal converter and simultaneously inputs design specifications such as diameter and material of the tube T to be measured. The design specification of the measuring tube and the digital signal inputted from the data input / storage unit 30 are sent to the analyzer 40.

The analysis device 40 receives the digital signal for the tube to be measured and the design specification of the tube and compares it with the set value for the calibration block C stored therein, according to the program, the degree of corrosion of the tube and the remaining life of the tube according to the program. Yields

Output the result to the output device.

According to the present invention described above, a small-sized probe is inserted into the tube of the heat exchanger (E), and then the corrosion of the inside of the tube is inspected while rotating and reversing. The analysis device 40 used can quantitatively determine the degree of corrosion of the tube and the remaining life of the tube.

Therefore, according to the present invention, the inspection is convenient and the reliability of the inspection result can be increased, and thus, there is an effect of preventing the equipment failure due to corrosion of the pipe in advance.

Claims (7)

Transmitting ultrasonic waves toward the inner wall of the tube T continuously at each position while moving along the longitudinal direction of the tube T in the tube T of the heat exchanger E, and receiving the ultrasonic signal again as an electrical signal. Ultrasonic flaw detection head unit 10 to convert to; Ultrasonic flaw detection unit 20 connected to the ultrasonic flaw detection head unit 10 converts the ultrasonic signal for the coronation received by the ultrasonic flaw detection unit 20 into an electrical signal and displays it through a display unit 21 such as a monitor. ); A data input / storage unit 30 connected to the ultrasonic wave detection unit 20 to convert an electrical signal sent from the ultrasonic wave detection unit 20 into a digital signal and to input or modify a design specification of a tube to be measured T; The degree of corrosion of the pipe and the remaining life of the pipe according to the digital signal for the pipe corrosion converted by the data input / storage unit 30 and the design specifications of the tube input from the data input / storage unit 30 are variables. Heat exchanger tube corrosion measurement device using ultrasonic waves having a configuration including an analysis device 40 to be interpreted by the built-in program. According to claim 1, The ultrasonic flaw detection head portion 10 comprises a hollow casing (11) to allow water to flow inside; The casing 11 is supported concentrically with the casing 11 and transmits an ultrasonic beam B along a central axis direction or receives an ultrasonic beam B returned along a central axis direction of the casing 11. A transducer 12; A transducer for converting the ultrasonic beam B received by the transducer 12 into an electrical signal; An impeller 14 installed at the front end of the casing 11 so as to be freely rotated through the bearing 15 to rotate through the casing 11 and rotated by the force of water supplied into the tube T; It is fixed to the impeller 14 and reflects the ultrasonic beam (B) transmitted from the transducer 12 toward the inner wall of the tube (T) and the ultrasonic beam (B) reflected from the inner wall of the tube (T) A mirror 16 which reflects back to the transducer 12; And A fin 18 extending at the tip of the casing 11 in the longitudinal direction of the casing 11 via the cap 17 to reflect the ultrasonic pulse reflected from the mirror 16 back to the transducer 12. Heat exchanger tube corrosion measurement apparatus using ultrasonic waves, characterized in that made. 3. The casing (11) according to claim 2, characterized in that the casing (11) comprises a centering means (13) for supporting the casing (11) to be kept concentric with the tube (T) inside the tube (T). Heat exchanger tube corrosion measuring device using ultrasonic waves. 4. The centering means (13) according to claim 3, wherein the centering means (13) is made of an engineering plastic support tube (13a) whose outer diameter is slightly smaller than the inner diameter of the tube (T) to be measured, and the cushion member (13b) is formed on the outer circumference of the support tube (13a). ) Is coated to support the measurement tube (T) without a gap between the measurement tube (T) and the casing (11) according to the change in the inner diameter of the measurement tube (T). Heat exchanger tube corrosion measuring device. 3. The conveying apparatus of claim 2, further comprising a conveying apparatus for advancing and retracting the casing 11 in a longitudinal direction, wherein the conveying apparatus includes a servo motor connected to a rear end of the casing 11, and the servo motor rotates by a predetermined rotational speed. Heat exchanger tube corrosion measurement apparatus using ultrasonic waves, characterized in that consisting of an encoder that sends a signal to the servo motor. The heat exchanger tube corrosion measuring apparatus using ultrasonic waves according to claim 2, further comprising a guide tube for measuring the inlet tip inserted into the inlet tip of the tube under test (T). According to claim 2, Heat exchanger tube corrosion measurement apparatus using ultrasonic waves, characterized in that it further comprises a correction block (50) having a constant step in the inner diameter.