WO2021057288A1 - Pipe creep measurement system and method - Google Patents

Abstract

A pipe creep measurement system and method, comprising a pipe to be measured (1), an ultrasound module (4), a temperature module (6), a host computer (7), a first ultrasonic transducer (2) used to generate an ultrasonic wave signal, a second ultrasonic transducer (3) used to convert a received ultrasonic wave signal into an electrical signal, and a temperature sensor (5) used to detect a pipe wall temperature of the pipe to be measured (1); the host computer (7) being connected to the ultrasound module (4) and the temperature module (6), an output terminal of the ultrasound module (4) being connected to the first ultrasonic transducer (2), the second ultrasonic transducer (3) being connected to an input terminal of the ultrasound module (4), the temperature sensor (5) being connected to an input terminal of the temperature module (6), and an ultrasonic wave emitted by the first ultrasonic transducer (2) being transmitted to the second ultrasonic transducer (3) after passing through a circumferential surface of the pipe to be measured (1). The present system and method can measure creep of a pipe, are characterized by convenient operation, accurate detection results and low human error, and can largely prevent temperature changes from affecting a creep measurement result.

Description

Pipeline creep measurement system and method Technical field

The invention relates to a digital measurement system and method, in particular to a pipeline creep measurement system and method.

Background technique

Long-term operation of power plant boiler steam pipes under high-temperature and high-pressure working conditions will cause high-temperature creep damage. Accumulation of damage and stress superimposition to a certain degree will cause the steam pipe to leak or burst, which seriously threatens the safe operation of the power station. Through regular creep measurement and data analysis of pipelines, we can grasp the creep law of steam pipeline metal in time, and provide a reliable technical basis for the correct analysis and prediction of the remaining life of the pipeline.

At present, the commonly used steam pipeline creep measurement methods are mainly divided into two types. The first is the creep measurement point measurement method, that is, the method of measuring the diameter of the supervision section with a micrometer when the machine is stopped, and the second is the creep measurement mark measurement method. That is, a steel tape rule made of Invar alloy is wound on the outer surface of the pipe measurement section to measure the circumference of the section. Both methods are directly measured with a length measuring tool. The creep measuring point measurement method has the following limitations: 1) The two measuring points in the diameter direction are difficult to align during installation and welding. In addition, the measuring points are easy to fall off after long-term use. Once the measuring points fall off, the entire set of measuring points The previous measurement data will be meaningless; 2) The micrometer used for measurement is heavy, bulky, inconvenient to operate, and requires multiple people to work at the same time; 3) The measurement result is greatly affected by the ambient temperature. In order to improve the measurement accuracy, the measurement The micrometer needs to be placed next to the pipeline to be measured for at least 0.5 hours; 4) The direction of pipeline creep is not balanced, and the maximum creep direction may not be at the measuring point, causing false measurements. The creep measurement marking measurement method also has similar limitations: 1) The steel tape ruler used for measurement is large, requiring multiple people to work, and the operation is inconvenient; 2) The ambient temperature has a greater influence on the measurement result, and the temperature of the steel tape ruler The ambient temperature is the same; 3) Different measurement personnel will produce human errors during the measurement process. Due to the very small amount of pipeline creep deformation, the accuracy of the two measurement methods is difficult to meet the requirements, often resulting in irregular measurement data, and even the following pipe diameter or circumference measurement value is less than the previous measurement value. Creep supervision is meaningless. Therefore, DL/T 438-2016 "Metal Technology Supervision Regulations for Thermal Power Plants" cancels the mandatory requirements for creep measurement, and the industry standard DL/T 441 "Supervision of Creep of High Temperature and High Pressure Steam Pipes in Thermal Power Plants" has been used for decades. The Regulations lost their original intention.

In view of the limitations of existing measurement methods, it is necessary to develop a convenient and accurate pipeline creep measurement system and method, which will provide strong technical support for the assessment of the safety status of high-temperature pipelines.

Summary of the invention

The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art, and design a pipeline creep measurement system and method, which can measure the creep of the pipeline, and has convenient operation, accurate detection results and small human errors. The characteristics of this can avoid the influence of temperature changes on the creep measurement results to the greatest extent.

In order to achieve the above purpose, the pipeline creep measurement system of the present invention includes the pipeline to be tested, an ultrasonic module, a temperature module, a host computer, a first ultrasonic transducer for generating ultrasonic signals, and a first ultrasonic transducer for generating ultrasonic signals. A second ultrasonic transducer converted into an electrical signal and a temperature sensor used to detect the temperature of the pipe wall to be measured;

The host computer is connected to the ultrasonic module and the temperature module, the output end of the ultrasonic module is connected to the first ultrasonic transducer, the second ultrasonic transducer is connected to the input end of the ultrasonic module, and the temperature sensor is connected to the input end of the temperature module. Connected, the ultrasonic waves emitted by the first ultrasonic transducer propagate to the second ultrasonic transducer after passing through the circumferential surface of the pipeline to be measured.

The upper computer includes a processor and a memory and a display connected to the processor, wherein the processor is connected to the ultrasonic module and the temperature module.

The first ultrasonic transducer and the second ultrasonic transducer are connected with the ultrasonic module through a shielded cable.

The pipeline creep measurement method of the present invention includes the following steps:

1) Input the material grade of the pipeline to be tested, the linear expansion coefficient δ _T of the pipeline material to be tested at different temperatures, the ultrasonic sound velocity μ _{T of} the pipeline material to be tested at different temperatures, and the first ultrasonic transducer and _{The distance L S} between the second ultrasonic transducers;

2) measuring the temperature of the module under test pipe wall temperature information T _x by the temperature sensor, the temperature information measured and the pipe wall resulting T _x of the detection is sent to the host computer;

_{3) The upper computer calculates the linear expansion coefficient δ Tx of} the pipeline material to be measured by linear interpolation according to the temperature information T _{x of} the pipeline wall to be measured;

_{4) The host computer calculates the ultrasonic sound velocity μ Tx} in the pipe material to be measured by linear interpolation according to the temperature information T _{x of} the pipe wall to be measured;

5) The host computer controls the ultrasonic module to generate a first electrical signal, and sends the first electrical signal to the first ultrasonic transducer. The first ultrasonic transducer converts the first electrical signal into an ultrasonic signal, so The ultrasonic signal enters the second ultrasonic transducer after passing through the circumferential surface of the pipeline to be tested, and is converted into a second electrical signal by the second ultrasonic transducer and then sent to the ultrasonic module, and the host computer records the first ultrasonic transducer time t time ₁ emits ultrasonic transducer and the second ultrasonic transducer receives ultrasonic waves to t _2;

6) The upper computer calculates the original perimeter of the pipe section to be tested when _{the pipe wall temperature is T x C=μ Tx} *(t ₂ -t ₁ )+L _S ;

Original cross-sectional circumference _{C 0 = C * (1-} T x * δ Tx at 7) the upper test pipe wall temperature computing converted to _{0 ℃) = [μ Tx *} (t 2 -t 1) + L S ]*(1-T _x *δ _Tx );

8) After the pipeline to be tested has been running at high temperature for W time, the temperature sensor measures the pipe wall temperature T′ _{x of} the pipeline to be tested, and then calculates the linear expansion coefficient δ′ _{Tx of} the pipeline material to be tested at a temperature of T′ _{x by linear interpolation.} and ultrasonic velocity μ _'Tx, while recording the first host computer ultrasonic transducer emits ultrasonic time t' ₁ and a second ultrasonic transducer receives ultrasonic waves time t _'2, calculated in terms of the measured temperature of the pipe wall 0 _{The perimeter C′ 0} of the section after operation at ℃ is:

_{C '0 = [μ' Tx} * (t '2 -t' 1) + L S] * (1-T 'x * δ'Tx);

9) The host computer calculates and outputs the relative creep of the pipeline to be tested after high temperature operation for W time

The present invention has the following beneficial effects:

The pipeline creep measurement system and method of the present invention uses the principle of ultrasonic distance measurement to control the ultrasonic signal to propagate one circle along the circumferential surface of the pipeline during specific operation, and calculate the current pipeline current by using the time difference between the ultrasonic signal sent and the ultrasonic signal received At the same time, the pipe creep is calculated by combining the current wall temperature of the pipe. It should be noted that the present invention introduces the ultrasonic sound velocity at different temperatures and the linear expansion coefficient of the material into the creep calculation, so as to avoid the influence of temperature changes on the creep to the greatest extent. Change the influence of the measurement result, convenient operation, accurate measurement result, and small human operation error.

Description of the drawings

Figure 1 is a schematic diagram of the structure of the present invention;

Among them, 1 is the pipeline to be tested, 2 is the first ultrasonic transducer, 3 is the second ultrasonic transducer, 4 is the ultrasonic module, 5 is the temperature sensor, 6 is the temperature module, and 7 is the upper computer.

detailed description

The present invention will be further described in detail below with reference to the accompanying drawings. It is worth noting that the schematic structural diagram shown in FIG. The definition of the system may include more or fewer components than shown, or a combination of certain components, or different component arrangements.

Referring to Figure 1, the pipeline creep measurement system of the present invention includes a pipeline to be tested 1, an ultrasonic module 4, a temperature module 6, a host computer 7, a first ultrasonic transducer 2 for generating ultrasonic signals, and The second ultrasonic transducer 3 for converting the received ultrasonic signal into an electrical signal and a temperature sensor 5 for detecting the temperature of the pipe wall of the pipeline 1 to be measured; the upper computer 7 is connected to the ultrasonic module 4 and the temperature module 6, and the ultrasonic module 4 The output end is connected to the first ultrasonic transducer 2, the second ultrasonic transducer 3 is connected to the input end of the ultrasonic module 4, the temperature sensor 5 is connected to the input end of the temperature module 6, and the first ultrasonic transducer 2 The emitted ultrasonic wave propagates to the second ultrasonic transducer 3 after passing through the circumferential surface of the pipeline 1 to be measured.

The host computer 7 includes a processor and a memory and a display connected to the processor. The processor is connected to the ultrasonic module 4 and the temperature module 6; the first ultrasonic transducer 2 and the second ultrasonic transducer 3 pass through shielded wires The cable is connected to the ultrasound module 4.

The pipeline creep measurement method of the present invention includes the following steps:

1) Input the material grade of the pipe 1 to be tested, the coefficient of linear expansion δ _T of the material of the pipe 1 to be tested at different temperatures, the ultrasonic sound velocity μ _{T of the} material of the pipe 1 to be tested at different temperatures, and the first ultrasonic wave into the upper computer 7. _{The distance L S} between the transducer 2 and the second ultrasonic transducer 3;

2) measuring the temperature of the module 6 on the measured temperature information T _x pipe wall 1 through the temperature sensor 5, the detected temperature information obtained by the test duct wall 1 T _x of the transmission to the host computer 7;

_{3) The upper computer 7 calculates the linear expansion coefficient δ Tx of the} material of the pipeline 1 to be measured by linear interpolation _{according to the temperature information T x of} the pipe wall of the pipeline 1 to be measured;

Among them, the linear expansion coefficient is generally discrete enumerated type data, that is, the linear expansion coefficient of the material under _{specific temperature parameters T 1} , T ₂ , T ₃ …T _{n δ T1} , δ _T2 , δ _T3 … δ _Tn ;

Assume that T ₁ , T ₂ , T ₃ … T _n , T _n+1 … are the temperature parameters that have been input to the host computer 7 and contain the corresponding linear expansion coefficient, and T ₁ ＜T ₂ ＜T ₃ ＜…＜T _n ＜T _n+1 ＜…, if the wall temperature T _{x of} the pipeline 1 to be measured is exactly between T _n and T _n+1 , that is, T _n ≤ T _x ＜ T _n+1 , the material is at T _n linear expansion coefficient δ _Tn, T _{n + 1} is the temperature coefficient of linear expansion when the material is δ _{Tn + 1,} the linear expansion coefficient of the material temperature T _x of

When a higher precision linear expansion coefficient is required, other interpolation methods can be used, such as Newton interpolation, Lagrangian interpolation, Hermite interpolation, etc.

_{4) The host computer 7 calculates the ultrasonic sound velocity μ Tx} in the material of the pipe 1 to be measured by linear interpolation _{according to the temperature information T x of} the pipe wall of the pipe 1 to be measured;

Among them, the ultrasonic sound velocity is generally discrete enumerated type data, that is, the ultrasonic propagation velocity in the material under _{specific temperature parameters T 1} , T ₂ , T ₃ …T _{n , μ T1} , μ _T2 , μ _T3 … μ _Tn ;

Specifically, suppose that T ₁ , T ₂ , T ₃ … T _n , T _n+1 … are the temperature parameters that have been input to the host computer 7 and contain the corresponding ultrasonic sound velocity, and T ₁ ＜T ₂ ＜T ₃ ＜… ＜T _n ＜T _n+1 ＜…, if the wall temperature T _{x of} the pipe 1 to be measured is exactly between T _n and T _n+1 , that is, T _n ≤T _x ＜T _n+1 , when the temperature is T _n The ultrasonic sound speed in the material is μ _{Tn , the ultrasonic sound speed in the material is μ Tn+1} when the temperature is T _n+1 , then the ultrasonic sound speed in the material when the temperature is T _x

5) The host computer 7 controls the ultrasonic module 4 to generate a first electrical signal, and sends the first electrical signal to the first ultrasonic transducer 2, and the first ultrasonic transducer 2 converts the first electrical signal into Ultrasonic signal, the ultrasonic signal enters the second ultrasonic transducer 3 after passing through the surface of the pipeline 1 to be tested, and is converted into a second electrical signal by the second ultrasonic transducer 3 and then sent to the ultrasonic module 4, the upper position recording unit 7 first ultrasonic transducer 2 emits an ultrasonic time t ₁ of a second ultrasonic wave receiver and the ultrasonic transducer time 3 t _2;

6) The upper computer 7 calculates the original perimeter of the section of the pipe 1 to be tested when the _{temperature of the pipe wall 1 is T x C=μ Tx} *(t ₂ -t ₁ )+L _S ;

7) The host computer 7 calculates the original perimeter of the section when the temperature of the pipe wall 1 to be measured is converted to 0℃ C ₀ ＝C*(1-T _x *δ _Tx )=[μ _Tx *(t ₂ -t ₁ )+ L _S ]*(1-T _x *δ _Tx );

8) After the pipeline 1 under test has been running at high temperature for W time, the wall temperature of the pipeline 1 measured by the temperature sensor 5 is T′ _x , and the material of the pipeline 1 under test is calculated by linear interpolation when the temperature is T′ _x linear expansion coefficient δ _'Tx and ultrasonic velocity μ' _Tx, while the host computer 7 records the first ultrasonic transducer 2 emits an ultrasonic time t _'1 and the second ultrasonic wave receiving time ultrasonic transducer 3 t' _2, be calculated When the wall temperature of the pipeline 1 is converted to 0℃, the perimeter C′ ₀ of the section of pipeline 1 to be measured after operation is:

C′ ₀ =[μ′ _Tx *(t′ ₂ -t′ ₁ )+L _S ]*(1-Tx′*δ′ _Tx )

9) The host computer 7 calculates and outputs the relative creep of the pipeline 1 to be tested after high temperature operation for W time

Claims (4)

1. A pipeline creep measurement system, which is characterized by comprising a pipeline to be tested (1), an ultrasonic module (4), a temperature module (6), a host computer (7), and a first ultrasonic transducer for generating ultrasonic signals (2) A second ultrasonic transducer (3) for converting the received ultrasonic signal into an electrical signal, and a temperature sensor (5) for detecting the temperature of the pipe wall of the pipeline (1) to be measured;

   The upper computer (7) is connected with the ultrasonic module (4) and the temperature module (6), the output end of the ultrasonic module (4) is connected with the first ultrasonic transducer (2), and the second ultrasonic transducer (3) It is connected to the input end of the ultrasonic module (4), the temperature sensor (5) is connected to the input end of the temperature module (6), and the ultrasonic waves emitted by the first ultrasonic transducer (2) pass through the pipeline (1) to be tested. After the surface, it propagates to the second ultrasonic transducer (3).
2. The pipeline creep measurement system according to claim 1, characterized in that the upper computer (7) includes a processor and a memory and a display connected to the processor, wherein the processor and the ultrasonic module (4) and the temperature module ( 6) Phase connection.
3. The pipeline creep measurement system according to claim 1, wherein the first ultrasonic transducer (2) and the second ultrasonic transducer (3) are connected to the ultrasonic module (4) through a shielded cable.
4. A method for measuring pipeline creep, which is characterized in that, based on the pipeline creep measurement system of claim 1, comprising the following steps:

   1) Input the material grade of the pipe to be tested (1), the linear expansion coefficient δ _T of the material to be tested (1) at different temperatures into the upper computer (7), and the ultrasonic wave of the material to be tested at different temperatures (1) The speed of sound μ _{T and the distance L S} between the first ultrasonic transducer (2) and the second ultrasonic transducer (3);

   2) the temperature of the module (6) (5) to be measured of the measuring pipe (1) wall temperature information T _x, and detecting the resulting test conduit (1) wall temperature T _x of the information sent to the host computer by the temperature sensor (7);

   3) The upper computer (7) _{calculates the linear expansion coefficient δ Tx of the} material of the pipeline (1) to be tested by linear interpolation _{according to the temperature information T x of the} pipe wall of the pipeline to be tested (1);

   4) The host computer (7) _{calculates the ultrasonic sound velocity μ Tx} in the material of the pipeline (1) to be tested by linear interpolation _{according to the temperature information T x of the} pipe wall to be tested (1);

   5) The host computer (7) controls the ultrasonic module (4) to generate a first electrical signal, and sends the first electrical signal to the first ultrasonic transducer (2), and the first ultrasonic transducer (2) The first electrical signal is converted into an ultrasonic signal, and the ultrasonic signal enters the second ultrasonic transducer (3) after passing through the circumferential surface of the pipeline (1) to be tested, and passes through the second ultrasonic transducer (3) After being converted into a second electrical signal, it is sent to the ultrasonic module (4), and the host computer (7) records the time t _{1 when the} first ultrasonic transducer (2) emits ultrasonic waves and the time when the second ultrasonic transducer (3) receives ultrasonic waves t ₂ ;

   6) The upper computer (7) calculates the original perimeter of the section of the pipe to be tested (1) when the pipe _{wall temperature is T x C=μ Tx} *(t ₂ -t ₁ )+L _S ;

   7) The upper computer (7) calculates the original perimeter of the section when the pipe wall temperature is converted to 0℃ C ₀ ＝C*(1-T _x *δ _Tx )=[μ _Tx *(t _2- t ₁ )+L _S ]*(1-T _x *δ _Tx );

   8) After the pipeline to be tested (1) has been running at high temperature for W time, the temperature sensor (5) measures the pipe wall temperature T′ _{x of} the pipeline to be tested (1), and then calculates the temperature of the pipeline to be tested (1) by linear interpolation. Is the linear expansion coefficient δ′ _Tx and the ultrasonic sound velocity μ′ _Tx when T′ _x , while the upper computer (7) records the time t′ _{1 when the} first ultrasonic transducer (2) emits ultrasonic waves and the second ultrasonic transducer ( 3) The time t′ _{2 of receiving the ultrasonic wave, the calculated circumference C′ 0} of the pipe to be measured (1) when the pipe wall temperature is converted to 0℃ is:

   _{C '0 = [μ' Tx} * (t '2 -t' 1) + L S] * (1-T 'x * δ'Tx);

   9) The upper computer (7) calculates and outputs the relative creep of the pipeline to be tested (1) after high temperature operation for W time

   

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