CN104406751A - System for testing high-temperature pipeline flange under action of outer bending moment - Google Patents

Abstract

The invention discloses a high-temperature pipeline flange test system under the action of external bending moment, which includes a left pipeline, a right pipeline, and a flange connecting the left pipeline and the right pipeline. The flange is sealed by a gasket, the left pipeline, The right pipe and the flange form a flange cavity to be tested; the left pipeline is connected to the pump through a valve, and the right pipeline is welded to a blind plate; a temperature sensor, a pressure sensor, and an electric heating device are installed in the flange cavity to be tested; the method A flange leakage testing mechanism is arranged outside the flange, and the flange leakage testing mechanism includes a leak testing cavity surrounded by a leak testing wall. The leak testing wall is provided with an exhaust valve and a bottom outlet valve. A temperature sensor and a pressure sensor are arranged in the cavity; the system also includes an external bending moment loading mechanism and a stress testing mechanism. The invention has accurate stress measurement and high leakage measurement accuracy, and has strong guiding significance for scientific research and engineering.

Description

High temperature pipeline flange test system under external bending moment

technical field

The invention relates to a flange testing system, in particular to a high-temperature pipeline flange testing system under the action of an external bending moment. the

Background technique

Flange connection is a commonly used connection method in petrochemical equipment. Because of its advantages of easy disassembly and installation, it is widely used in pressure vessels and pipelines in petrochemical, nuclear power, metallurgy, pharmaceutical and other industries. With the increasingly prominent contradiction between economic development and energy supply, and the rapid development of oil refining and chemical technology, high temperature and high pressure conditions are common in various refining and chemical equipment. Under high temperature operating conditions, changes such as deflection, warping, creep, and crack growth may occur in the flange, and the stress changes in various parts of the flange are complicated; when there is an external bending moment, the stress characteristics of each part of the flange will also change greatly. Changes, deflection, warping, cracks may exacerbate leaks. High temperature flange leakage is one of the main causes of major accidents in petrochemical and other enterprises. Therefore, it is necessary for us to design a high-temperature pipeline flange test system under the action of external bending moment to analyze the leakage rate of the high-temperature flange under the action of external bending moment and the complex stress on the flange to ensure the safety of the pipeline connection. the

Contents of the invention

The object of the present invention is to provide a high-temperature pipeline flange testing system under the action of external bending moment. The test system is applied to high-temperature flanges under the action of external bending moment, and can accurately test the stress of the outer wall of the flange and the leakage of the flange to ensure The smooth progress of production and construction. the

The present invention is achieved as follows: a high-temperature pipeline flange testing system under the action of external bending moment, which includes a left pipeline, a right pipeline, and a flange connecting the left pipeline and the right pipeline, and the flange is sealed by a gasket. The left pipe, the right pipe, and the flange form a flange cavity to be tested;

The left pipeline is connected to the pump through a valve, and the right pipeline is welded to a blind plate; a temperature sensor, a pressure sensor, and an electric heating device controlled by an electric heater and electric cabinet are arranged in the cavity of the flange to be tested;

A flange leakage testing mechanism is arranged outside the flange, and the flange leakage testing mechanism includes a leakage detection cavity surrounded by a leakage detection wall, and an exhaust valve and a bottom outlet valve are arranged on the leakage detection wall. The exhaust valve and the bottom outlet valve can also be used to fill the medium, and the leak detection cavity is equipped with a temperature sensor and a pressure sensor;

The system also includes an external bending moment loading mechanism and a stress testing mechanism. The external bending moment loading mechanism includes a hydraulic loading device, and the hydraulic loading device applies force to the left and right pipelines to form an outer bending moment on the pipelines at the flange connection. Moment, the size of the moment can be adjusted freely, the stress testing mechanism includes strain gauges, and the strain gauges are connected with the strain gauges and the computer through cables. the

The strain gauges are evenly distributed on the left pipe cylinder section, the right pipe cylinder section, the flange cone neck section and the outer wall of the flange plate. the

In the high-temperature pipeline flange test system under the action of external bending moment, a pump is installed at the left end of the cavity to be tested in the flange, and there is a valve on the output pipeline of the pump. The output pipeline is directly connected to the left pipeline, and the medium is pumped by the pump It is transported to the cavity of the flange to be tested, and a pressure sensor and a temperature sensor are set in the cavity of the flange to be tested. The temperature sensor monitors the temperature of the medium in the cavity of the flange to be tested. The pressure in the cavity; the lower part of the pipeline is provided with a support bracket, and the upper part of the pipeline is provided with an exhaust valve; the flange is connected by bolts and sealed with a gasket; the middle part of the flange to be tested is provided with an electric heating device, It can heat the medium in the cavity of the flange to be measured. the

The external bending moment loading mechanism is mainly composed of a liquid crystal control panel, a hydraulic loading device, a loading bracket and a loading arm; the hydraulic loading device can be controlled by the liquid crystal control panel, and a reasonable loading can be performed according to the needs of the test, that is, it can provide Load from zero to any desired load value within the range. The loading bracket is welded as a whole with the extension rod of the hydraulic loading device. The hydraulic loading device can provide a force of any size within the range. The loading bracket is provided with a loading arm. The loading arm can move left and right on the loading bracket, and cooperate with the support under the pipeline to provide different types of bending moments. The loading arm is in contact with the left pipe and the right pipe. the

The flange leakage testing mechanism is mainly composed of a leak detection cavity, a temperature sensor, and a pressure sensor; the leakage detection cavity is provided with a valve for inputting a measurement medium, which is convenient for use when it needs to be filled with a measurement medium; The leak detection cavity is provided with a vent hole and an underflow port; the flange stress testing mechanism mainly includes strain gauges and strain gauges, and the strain gauges are evenly distributed on the pipe cylinder section, the flange cone neck section and the flange plate On the outer wall; the electrical signal change of the strain gauge is transmitted to the strain gauge and the computer by the cable. the

The high temperature pipeline flange test system under the action of external bending moment is mainly composed of pipeline flange connection mechanism (pipeline flange connection mechanism is composed of pump, pipe, flange, blind plate, etc.), medium heating mechanism, external bending moment loading mechanism and stress The test mechanism consists of a pump that creates a high-pressure environment in the flange cavity to be tested. An electric heating device is installed in the middle of the flange cavity to be tested to heat the medium in the flange cavity to be tested to a specified temperature. The temperature and pressure sensors come Measure the temperature and pressure of the flange cavity to be tested. The external bending moment loading mechanism applies any force within the range of the hydraulic loading device to the pipelines (left pipeline and right pipeline) at both ends of the flange. The force is combined with the support below the pipeline to form a bending moment. The size of the moment. the

The invention uses a pump or an air compressor to provide a high-pressure environment for the pipeline flange connection mechanism, and uses an electric heating device to provide a high-temperature environment for the pipeline flange. It can perform tests under multiple sets of temperature and pressure conditions, and can measure the flange connection at high temperature and high pressure. Conditions to withstand the leakage rate under the action of external bending moment. The invention is applicable to both liquid medium and gaseous medium. The invention can not only check whether the flange connection leaks and measure the leakage rate, but also can accurately test the stress on the cylindrical section of the pipeline, the tapered neck section and the outer wall of the flange, and monitor the stress on the flange under different pressure and temperature conditions in real time. The stress level is determined to determine whether there are internal cracks and crack propagation. The invention has accurate stress measurement and high leakage measurement accuracy, and has strong guiding significance for both scientific research and engineering. the

Description of drawings

Figure 1 is a schematic diagram of the structure of the high-temperature pipeline flange test system under the action of external bending moment. the

Fig. 2 is an enlarged view of A in Fig. 1 . the

In the figure: 1-pump, 2-valve, 3-exhaust valve, 4-left pipe, 5-electric heating device, 6-flange, 7-LCD control panel, 8-loading bracket, 9-leakage detection cavity , 10-exhaust valve, 11-hydraulic loading device, 12-gasket, 13-right pipe, 14-blind plate, 15-electric heater cabinet, 16-right support, 17-underflow valve, 19-underflow Valve, 20-temperature sensor, 21-pressure sensor, 22-left support, 23-temperature sensor, 24-pressure sensor, 25-computer, 26-strain gauge, 27-strain gauge, 28-loading arm. the

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings. the

As shown in Figure 1 and Figure 2, a high-temperature pipeline flange testing system under the action of external bending moment, it includes a left pipeline 4, a right pipeline 13, and a flange 6 connecting the left pipeline 4 and the right pipeline 13, the method The flange 6 is connected by bolts and sealed with a gasket 12. The left pipe 4, the right pipe 13, and the flange 6 form a flange cavity to be tested. The left pipe 4 is provided with an exhaust valve 3, and the right The pipeline 13 is provided with an underflow valve 17;

The left pipeline 4 is connected with the pump 1 through the valve 2, and the right pipeline 13 is welded with the blind plate 14; a temperature sensor 23 and a pressure sensor 24 are arranged in the cavity of the flange to be measured, and are controlled by an electric heater electric cabinet 15 The electric heating device 5, the temperature sensor 23 monitors the temperature of the medium in the flange cavity to be measured, the pressure sensor 24 measures the pressure in the flange cavity to be measured, and the electric heating device 5 can control the flange cavity to be measured The inner medium is heated;

The flange 6 is provided with a flange leakage testing mechanism, and the flange leakage testing mechanism includes a leakage detection cavity 9 surrounded by a leakage detection wall, and the leakage detection wall is provided with an exhaust valve 10, an underflow port The valve 19, the exhaust valve 10 and the bottom outlet valve 19 can not only exhaust, but also can be used to input or remove the medium; the leak detection cavity 9 is provided with a temperature sensor 20, a pressure sensor 21, a temperature sensor 20, a pressure sensor 21 It can measure the temperature and pressure of the medium in the leak detection cavity 9;

The system also includes an external bending moment loading mechanism and a stress testing mechanism, the external bending moment loading mechanism includes a hydraulic loading device 11 controlled by a liquid crystal control panel 7, and the extension rod of the hydraulic loading device 11 is connected to the loading bracket 8 As a whole, the loading bracket 8 is provided with a loading arm 28, the hydraulic loading device 11 can provide a force of any size in the range, the loading arm 28 is in contact with the left pipeline 4 and the right pipeline 13, the loading arm 28 can be Move left and right on the loading bracket 8, and cooperate with the right bearing 16 and the left bearing 22 to provide different types of bending moments of different sizes; the stress testing mechanism includes a strain gauge 27, a computer 25 and a strain gauge 26, and the strain Sheets 27 are evenly distributed on the left pipe cylinder section, the right pipe cylinder section, the flange cone neck section and the outer wall of the flange plate, the strain gauges are evenly distributed along the ring direction, and the strain gauges 27 are connected with the strain Instrument 26 and computer 25 are connected. the

In order to ensure the accuracy of measurement, the left pipe 4 is provided with a left support 22 , and the right pipe 13 is provided with a right support 16 . the

The loading arm 28 can move left and right on the loading bracket 8 to the inside and outside of the left support 22 and the right support 16 to load different types of bending moments. The loading arms 28 can be symmetrical or asymmetrical to provide different types of bending moments. the

The pump 1 is used to transport the medium (liquid or gas) into the cavity of the flange to be tested, and form a high-pressure environment in the cavity of the flange to be tested, and a valve 3 is arranged on the pipeline of the cavity to be tested in the flange to The flange is used for exhaust when the cavity to be tested is filled with a medium; the electric heater 5 is used to raise the temperature of the medium to a certain temperature, and the heating intensity of the electric heater 5 is controlled by the electric heater electric cabinet 15 . A temperature sensor 23 and a pressure sensor 24 are arranged in the cavity to be tested in the flange to monitor the temperature and pressure of the medium in the cavity to be tested in the flange in real time. Blind plate 14 is welded on right pipeline end, and its sealing effect is good, and electric heating device 5 is installed and guaranteed sealing is good. the

There is a leak detection cavity 9 on the periphery of the flange 6. When the medium leaks out of the cavity to be tested in the flange, it will affect the pressure of the medium in the leakage detection cavity 9, thus reflecting the quality change of the medium in the leakage detection cavity. rate or volume change rate; the leak detection cavity 9 is provided with a temperature sensor 20 and a pressure sensor 21, which can measure the temperature and pressure of the medium in the leak detection cavity 9; the leak detection cavity 9 is provided with a drain Air valve 10, bottom flow port valve 19, bottom flow port valve 19 is used to fill the medium, when the filling medium is a liquid medium, the exhaust valve 10 can exhaust, and the bottom flow port valve 19 is used to release pressure or eliminate the leak detection cavity 9 medium; the volume of the leak detection cavity 9 can be measured by the exhaust valve 10 and the bottom outlet valve 19 by the drainage method. the

A hydraulic loading device 11 is fixed above the pipe in the cavity of the flange to be tested. The hydraulic loading device 11 applies a bending moment to the pipes (left pipe, right pipe) at both ends of the flange through the loading bracket 8 welded together with its extension rod. , the hydraulic loading device 11 can be controlled by its own liquid crystal control panel 7 to apply the load in any range; the loading bracket is provided with a loading arm, and the loading arm is in contact with the left pipeline and the right pipeline; Moving left and right on the loading bracket, the loading arm works with the supports on the pipe (left support, right support) to provide different types of bending moments. the

As shown in Figure 2, strain gauges 27 are evenly pasted on the outer walls of the flange, taper neck, left pipe, and right pipe. 27 measure the stress of each position on the flange, and display the strain, leakage rate, stress and its variation with time in the strain gauge 26 and the computer 25 in real time. the

The temperature sensor 20 , the pressure sensor 21 , the temperature sensor 23 and the pressure sensor 24 can send signals to the computer 25 for display, and can also be sent to the single chip microcomputer for display. the

Working engineering of the present invention:

(1) Before the high-temperature pipeline flange test system works under the action of external bending moment, the computer 25 is turned on for standby use, the strain gauge 26 is turned on and preheated, and the valve 2, the exhaust valve 3, the underflow port valve 17, the exhaust valve 10, and the underflow valve are checked. If the medium in the cavity of the flange to be tested is liquid, fill the cavity with the same liquid to be tested in the initial state, and record the initial working temperature and pressure; if the cavity of the flange to be tested is If the cavity is a gaseous medium, the leak detection cavity is filled with the same gas to be tested in the initial state, and the initial working temperature and pressure are recorded, and the hydraulic loading device 11 is turned on for standby;

(2) When the high-temperature pipeline flange testing system is working under the action of external bending moment, the pump 1 fills the cavity of the flange to be tested with the medium, and the pressure sensor 24 displays the pressure in the cavity of the flange to be tested, and adjusts the pressure to the cavity to be tested. Pressure; turn on the electric heating device 5, rely on the temperature sensor 23 to display the temperature in the cavity of the flange to be measured, and adjust the medium temperature to the temperature to be measured. The rate is measured in real time, and the stress change on the flange is jointly monitored by the strain gauge 26 and the computer 25. the

Under high temperature conditions (temperature and pressure to be measured), if the pressure is maintained for a long enough time, if the data measured by the temperature sensor 20 and the pressure sensor 21 of the leak detection cavity 9 do not satisfy the gaseous state equation or the temperature and volume change law of the liquid, Promptly in this process, if the pipeline pressure sensor 24 readings in the cavity to be tested in the flange becomes smaller, and the pressure sensor 21 readings in the leakage detection cavity becomes larger, then it can be judged that leakage occurs. When judging the leakage of the flange to be tested, the leakage rate can be calculated according to the following method. In addition, the strain gauge 26 and the computer 25 jointly monitor the stress change on the flange to be tested. the

Specifically, the leakage rate can be calculated by the following formula:

When the leakage medium is gas, the gas mass in the leak detection cavity is:

${\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; m</span>}\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; V</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

At the end of the leak test:

${\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; m</span>}\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; V</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Where: the volume of the leak detection cavity is V, and within the measurement time interval t, the pressure and temperature in the leak detection cavity change from p ₁ , T ₁ to p ₂ , T ₂ , M is the molecular mass of the medium, and R is the gaseous state constant, m ₁ is the mass of the initial state, and m ₂ is the mass of the final state.

The change of gas mass in time interval t is as follows:

$\mathrm{<span\; class="notranslate">\; \&Delta;m</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; V</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; V</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Where Δm is the quality difference. the

The volumetric leakage rate of the leaked gas is:

$\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&Delta;V</span>}}{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; t</span>}}\frac{\mathrm{<span\; class="notranslate">\; \&Delta;m</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}\frac{\mathrm{<span\; class="notranslate">\; R</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

Among them, ΔV is the volume difference, and L is the volume change rate. the

If the medium is liquid, formula (4) can be directly used for calculation. the

Here, the volume change rate is used to represent the leakage rate, and of course the mass change rate can also be used to represent the leakage rate, that is, Δm/t, which will not be repeated here. the

The invention can not only check whether the flange leaks, but also obtain the mass change rate or volume change rate of the medium through the test data. the

Claims (7)

1. A high-temperature pipeline flange testing system under the action of external bending moment, it comprises left pipeline, right pipeline, and the flange that connects left pipeline and right pipeline, and described flange adopts gasket to seal, left pipeline, right pipeline 1. The flange forms a cavity to be tested by the flange, which is characterized in that: The left pipeline is connected to the pump through a valve, and the right pipeline is welded to a blind plate; a temperature sensor, a pressure sensor, and an electric heating device controlled by an electric heater and electric cabinet are arranged in the cavity of the flange to be tested; A flange leakage testing mechanism is arranged outside the flange, and the flange leakage testing mechanism includes a leakage detection cavity surrounded by a leakage detection wall, and an exhaust valve and a bottom outlet valve are arranged on the leakage detection wall. A temperature sensor and a pressure sensor are arranged in the leak detection cavity; The system also includes an external bending moment loading mechanism and a stress testing mechanism, the external bending moment loading mechanism includes a hydraulic loading device, the hydraulic loading device applies force to the left pipe and the right pipe, and cooperates with the support, and the flange An external torque is formed on the pipeline at the joint, and the magnitude of the torque can be adjusted freely. The stress testing mechanism includes a strain gauge, and the strain gauge is connected with the strain gauge and the computer through a cable. 2. The high-temperature pipeline flange test system under the action of external bending moment according to claim 1, characterized in that: the extension rod of the hydraulic loading device is welded together with the loading bracket, and the hydraulic loading device can provide Any size of force, the loading bracket is provided with a loading arm, and the loading arm is in contact with the left pipeline and the right pipeline. 3. The high-temperature pipeline flange testing system under the action of external bending moment according to claim 2, characterized in that: the hydraulic loading device is controlled by a liquid crystal control panel. 4. The high-temperature pipeline flange testing system under the action of external bending moment as claimed in claim 2, characterized in that: the loading arm can move left and right on the loading bracket, and the loading arm cooperates with the supports on the left and right pipelines , providing different types and sizes of bending moments. 5. The high-temperature pipeline flange testing system under the action of external bending moment as claimed in claim 1, wherein the strain gauges are evenly distributed on the left pipeline cylinder section, the right pipeline cylinder section, the flange cone neck section and on the outer wall of the flange. 6 . The high-temperature pipeline flange testing system under the action of external bending moment according to claim 5 , wherein the strain gauges are evenly distributed along the circumferential direction. 7 . 7. The high-temperature pipeline flange testing system under the action of external bending moment according to claim 1, characterized in that: said left pipeline is provided with an exhaust valve, and said right pipeline is provided with a bottom outlet valve.