A pipe heat insulation performance testing device and testing method

Abstract

The application discloses a kind of pipe heat insulation performance testing device and testing method, step S1 test condition preparation: in the middle section of pipe body equidistantly along length direction arrangement n temperature sensors, two ends are respectively connected into constant-temperature water supply module and form circulating water path;Step S2 reference pipe body calibration test: through temperature sensor, obtain steady temperature value;Step S3 to be measured pipe body installation: the reference pipe body in step S1 is replaced by to be measured pipe body;Step S4 to be measured pipe body test: through temperature sensor, obtain steady temperature value;Step S5 performance comparison determination: compare the steady temperature data of reference pipe body and to be measured pipe body, complete the quantification determination of to be measured pipe body overall heat insulation performance;Step S6 heat insulation uniformity detection: according to the steady temperature data of each detection site of to be measured pipe body obtained in step S4, obtain the heat insulation performance of each pipe section of to be measured pipe body.The application can be suitable for the heat insulation performance test of pipe body.

Description

Technical Field

[0001] This invention relates to pipeline insulation performance testing technology, and more specifically, to a method for testing the insulation performance of pipe materials, and also to a device for testing the insulation performance of pipe materials. Background Technology

[0002] In engineering projects involving heat transmission, cryogenic fluid transport, and building water supply and drainage, the thermal insulation performance of pipes directly determines the system's energy loss, operating efficiency, and service life. The uniformity of thermal insulation along the length is a core indicator for evaluating pipe manufacturing quality and installation processes. Furthermore, in some high-precision pipeline applications, the thermal insulation performance of the pipe materials must be of a high standard. Authoritative thermal conductivity testing requires specialized instruments based on the heat shield method or heat flow meter method, which is complex to operate and demands high precision in sample preparation. The pipe material must be made into a flat plate before its thermal insulation performance is tested, making it unsuitable for directly testing the thermal insulation performance of pipes.

[0003] Therefore, a new technical solution is proposed to address the testing of pipe insulation performance. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a device and method for testing the thermal insulation performance of pipes.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for testing the thermal insulation performance of pipes, comprising the following steps:

[0007] Step S1 Test Condition Preparation: Place the reference tube in a constant temperature environment, and arrange n temperature sensors at equal intervals along the length of the tube in the middle section; seal both ends of the tube with plugs, and connect both ends of the tube to a constant temperature water supply module to form a circulating water circuit;

[0008] Step S2: Reference pipe calibration test: During the test, the inlet water temperature and inlet water flow rate are kept constant. After entering a steady state, the steady-state temperature value of each detection point is obtained through the temperature sensor.

[0009] Step S3 Installation of the tube to be tested: Replace the reference tube in step S1 with the tube to be tested;

[0010] Step S4 Test of the tube to be tested: Keep the conditions consistent with those in step S2 and test the tube to be tested; after entering a steady state, obtain the steady state temperature value of each detection point through the temperature sensor.

[0011] Step S5 Performance Comparison and Judgment: Compare the steady-state temperature data of the reference tube and the tube under test to determine the overall thermal insulation performance of the tube under test.

[0012] Step S6 Heat insulation uniformity detection: According to the steady-state temperature data of each detection position of the pipe body to be measured obtained in step S4, obtain the heat insulation performance uniformity of each pipe section of the pipe body to be measured.

[0013] Further, in step S2, after obtaining the steady-state temperature value, obtain the average steady-state temperature T0 of the reference pipe body as the reference for comparison and determination.

[0014] In step S4, after obtaining the steady-state temperature value, calculate the average steady-state temperature Tx of the pipe body to be measured.

[0015] Further, in step S2, the inlet water temperature is controlled at 60°C to 90°C, and the control accuracy of the inlet water temperature is ±0.2°C; in step S5, performance comparison and determination: if Tx < T0 and the difference between the two is ≥1°C, it is determined that the heat insulation performance of the pipe body to be measured is better than that of the reference pipe body; if Tx > T0 and the difference between the two is ≥1°C, it is determined that the heat insulation performance of the pipe body to be measured is inferior to that of the reference pipe body; if |Tx - T0| < 1°C, it is determined that the heat insulation performance of the pipe body to be measured meets the reference requirements.

[0016] Further, in step S6, calculate the heat transfer coefficient Ki of the pipe section between adjacent two sensors segment by segment, obtain the heat insulation uniformity coefficient U in the length direction of the pipe body to be measured based on the heat transfer coefficient Ki of each segment, and judge the heat insulation uniformity in the length direction of the pipe body according to the coefficient U.

[0017] The heat transfer coefficient Ki of the pipe section between adjacent two sensors is:

[0018]

[0019] c is the specific heat capacity at constant pressure of water; ρ is the density of water; q is the volume flow rate of the circulating water; ΔTi is the temperature drop of the fluid in the i-th pipe section, ΔTi = Tin - Tout, Tin is the inlet water temperature, and Tout is the outlet water temperature; dm is the average diameter of the pipe body insulation layer; d is the distance between adjacent sensors; ΔTm is the logarithmic mean temperature difference of the i-th pipe section.

[0020] The heat insulation uniformity coefficient U in the length direction of the pipe body to be measured is:

[0021]

[0022] Kmin is the minimum value of the heat transfer coefficient of all single pipe sections, and Kmax is the maximum value of the heat transfer coefficient of all single pipe sections.

[0023] Further, if U ≥ 0.9, it is determined that the heat insulation performance in the length direction of the pipe body is uniform; if 0.8 ≤ U < 0.9, it is determined that the heat insulation performance in the length direction of the pipe body is basically uniform and there are local minor defects; if U < 0.8, it is determined that the heat insulation performance in the length direction of the pipe body is non-uniform and there are obvious local defects.

[0024] Furthermore, piston-type plugs are used at both ends of the tube body to be tested. The piston-type plugs are connected to the piston of the tube body to be tested, which can be adjusted along the length of the tube body to be tested and maintain a seal.

[0025] It also includes step S7 displacement calibration detection, which is used to improve the detection accuracy of thermal insulation uniformity.

[0026] Further, step S7, displacement calibration detection, includes the following steps:

[0027] Step S7-1 Displacement Adjustment: Keep the position of the tube to be tested fixed, and move the piston plugs at both ends synchronously in the same direction along the length, adjusting the distance to ΔL;

[0028] Step S7-2 Steady-state test after displacement: Keep the test conditions completely consistent with steps S2 and S4, start the constant temperature water supply module until the system reaches thermal steady state, and collect the steady-state temperature data of each temperature sensor after displacement.

[0029] Step S7-3 Temperature Calculation:

[0030] Based on the friction temperature gradient Gx along the pipe body under test, obtain the theoretical temperature value of the same sensor after displacement. :

[0031] Tpi is the steady-state temperature value of the i-th sensor before displacement, Gx is the temperature gradient along the pipe body under test, and ΔL is the plug displacement adjustment amount.

[0032] Step S7-4 Temperature Deviation Calculation: Calculate the deviation between the theoretical temperature value and the actual measured value at the same detection location:

[0033] Tai is the actual steady-state measurement value of the i-th sensor after displacement;

[0034] Step S7-5: Heat transfer coefficient correction:

[0035] The segmented heat transfer coefficient Ki obtained in step S6 is corrected based on the single-detection position deviation ΔT to obtain the corrected accurate heat transfer coefficient:

[0036] ΔTm is the logarithmic mean temperature difference of the corresponding pipe section.

[0037] Furthermore, step S7, displacement calibration detection, also includes the following steps:

[0038] Step S7-6: Correction of heat insulation uniformity:

[0039] The accurate thermal insulation uniformity coefficient along the length direction is calculated based on the corrected Ki':

[0040] Kmin' is the minimum value of the heat transfer coefficient of each segment after correction, and Kmax' is the maximum value of the heat transfer coefficient of each segment after correction; the pipe length direction uniformity parameter after correction is obtained through U'; the location of local heat insulation defects in the pipe body is located through ΔT.

[0041] The present invention also provides a pipe insulation performance testing device, including a pipe body to be tested, a plug, a water pipe, a temperature sensor, a temperature recorder, a constant temperature water supply module, and a constant temperature environment chamber;

[0042] The plug is used to seal the two ends of the pipe body to be tested; the water pipe includes an inlet pipe and an outlet pipe, which are respectively connected to the corresponding plugs and can communicate with the inside of the pipe body to be tested, and are connected to the constant temperature water supply module to form a circulating water circuit.

[0043] There are n temperature sensors arranged along the length of the tube to be tested, used to collect temperature data of the tube. Each temperature sensor is electrically connected to a temperature recorder. The temperature recorder is also electrically connected to the water temperature sensors on the inlet and outlet pipes to obtain the inlet and outlet water temperatures.

[0044] The thermal insulation performance of the pipe body to be tested was tested using the aforementioned pipe insulation performance test method.

[0045] Furthermore, the plug is a piston-type plug, which is adapted to the inner circumference of the tube to be tested and can be adjusted along the length of the tube to be tested while maintaining a seal during adjustment.

[0046] In summary, the present invention has the following beneficial effects:

[0047] In this solution, plugs are installed directly at both ends of the pipe and connected to a constant temperature water supply module through water pipes to form a circulating water circuit. With the help of several temperature sensors arranged on the outside of the pipe, the temperature of each section of the pipe can be detected. By calculating and comparing the temperature of each section, the relevant thermal insulation performance parameters of the pipe under test can be obtained. There is no need to make a plate for half of the pipe, which improves the convenience of testing.

[0048] First, a reference tube is tested, and its performance is used as a unified benchmark. Then, the thermal insulation performance of the tube to be tested is tested under identical conditions. This ensures that the test data of the reference tube and the tube to be tested are comparable, enabling a rapid and accurate assessment of the overall thermal insulation performance of the tube to be tested.

[0049] By calculating the temperature parameters of each segment along the length of the pipe, the thermal insulation performance parameters of each segment along the length of the pipe can be obtained, thereby obtaining the uniformity of thermal insulation performance along the length of the pipe.

[0050] By setting the plug to a piston-type plug structure, the relative positions of the pipe body and the piston-type plug can be adjusted, thereby adjusting the relative distance between the circulating hot water inlet and the temperature sensor. Through adjustment, two sets of mutually misaligned test data can be generated. The same two temperature sensors are misaligned in the pipe sections before and after adjustment. By superimposing and overlapping the test states before and after adjustment, more densely distributed test point data can be obtained along the length of the pipe body. This can further correct system errors, improve uniformity detection accuracy, and simultaneously locate the location of local insulation defects. Attached Figure Description

[0051] Figure 1 This is a flowchart of the pipe insulation performance testing method in Example 1;

[0052] Figure 2 This is a partial structural schematic diagram of the pipe insulation performance testing device in Example 1;

[0053] Figure 3 This is a partial structural cross-sectional view of the pipe insulation performance testing device in Example 1;

[0054] Figure 4 This is a flowchart of the pipe insulation performance testing method in Example 2;

[0055] Figure 5 This is a flowchart of the pipe insulation performance testing method in Example 3;

[0056] Figure 6 This is a flowchart of step S7, displacement calibration and detection, in Example 3;

[0057] Figure 7 This is a schematic diagram of the pipe insulation performance testing device in Example 3 before adjustment;

[0058] Figure 8 This is a schematic diagram of the pipe insulation performance testing device after adjustment in Example 3.

[0059] Figure labels: 1. Test tube; 2. Plug; 3. Water pipe; 31. Inlet pipe; 32. Outlet pipe; 4. Temperature sensor; 5. Temperature recorder. Detailed Implementation

[0060] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] Example 1

[0062] This embodiment discloses a method for testing the thermal insulation performance of pipes, referring to... Figure 1 As shown, the steps include:

[0063] Step S1 Test Condition Preparation: Place the reference tube in a constant temperature environment, and arrange n temperature sensors at equal intervals along the length of the tube in the middle section; seal both ends of the tube with plugs, and connect both ends to a constant temperature water supply module to form a circulating water circuit;

[0064] In step S1, the number of temperature sensors n≥3, the spacing d between adjacent temperature sensors is 20-100cm, and all sensors avoid the pipe ends, interfaces and bracket positions.

[0065] Step S2: Reference Pipe Calibration Test: During the test, maintain a constant inlet water temperature and flow rate. The circulating water temperature generated by the constant temperature water supply module can be selected to be approximately between 60℃ and 90℃, with an inlet water temperature control accuracy of ±0.2℃ and an inlet water flow rate control accuracy of ±0.5%. The constant temperature environment temperature is maintained at 25℃, with fluctuations ≤ ±0.5℃. Circulate hot water through the reference pipe until the system reaches a steady state. The criteria for determining a steady state are: within 3 consecutive minutes, the inlet water temperature fluctuation ≤ ±0.2℃, and the temperature fluctuation of each temperature sensor ≤ ±0.3℃.

[0066] After entering steady state, the steady-state temperature value is obtained through temperature sensors, and the temperature values ​​of each temperature sensor are obtained. At the same time, the average steady-state temperature T0 of the outer wall of the reference tube, the reference friction temperature gradient G0, and the reference heat transfer coefficient K0 are calculated as the benchmark for performance comparison.

[0067] The average steady-state temperature T0 is:

[0068]

[0069] In the formula: Ti is the steady-state temperature value of the i-th temperature sensor, and n is the number of sensors.

[0070] Wherein, the reference friction temperature gradient G0 represents the steady-state temperature change per unit distance along the length of the reference tube, reflecting the uniformity of the temperature distribution along the length of the reference tube. Specifically, the reference friction temperature gradient G0 is:

[0071]

[0072] Where: Ti, d represents the steady-state temperature values ​​of two adjacent temperature sensors, and d is the distance between the adjacent sensors.

[0073] Wherein, the reference heat transfer coefficient K0 is:

[0074]

[0075] In the formula: c is the specific heat capacity at constant pressure of water; ρ is the density of water; q is the volume flow rate of the circulating water; ΔT is the overall temperature drop of the reference pipe body, ΔT = Tin - Tout, Tin is the inlet temperature, and Tout is the outlet temperature; dm is the average diameter of the insulation layer of the reference pipe body; L is the total length of the reference pipe body;

[0076] ΔTm is the logarithmic mean temperature difference of the reference pipe body:

[0077]

[0078] In the formula, Tenv is the constant temperature of the environment.

[0079] Step S3 Installation of the pipe to be tested: After the test of the reference pipe body is completed, replace the reference pipe body in Step S1 with the pipe to be tested, and then conduct tests on the pipe to be tested;

[0080] Step S4 Testing of the pipe to be tested: Keep the conditions the same as those in Step S2, that is, ensure that the state conditions of the pipe to be tested during the test are the same as those of the reference pipe body; enter the steady state under the same condition requirements, and then obtain the temperature value of the pipe to be tested when it enters the steady state through the temperature sensor;

[0081] After entering the steady state, obtain the steady state temperature value through the temperature sensor, obtain the temperature values of each temperature sensor, and synchronously calculate the average steady state temperature Tx of the outer wall surface of the pipe to be tested, the temperature gradient Gx along the path, and the heat transfer coefficient Kx. Each parameter is calculated in the same way as in Step S2.

[0082] Step S5 Performance comparison and determination: Compare the steady state temperature data of the reference pipe body and the pipe to be tested, and complete the quantitative determination of the overall heat insulation performance of the pipe to be tested;

[0083] Specifically, in Step S5, the specific rules for performance comparison and determination are as follows: If Tx < T0 and the difference between the two is ≥ 1 °C, it is determined that the heat insulation performance of the pipe to be tested is better than that of the reference pipe body; if Tx > T0 and the difference between the two is ≥ 1 °C, it is determined that the heat insulation performance of the pipe to be tested is inferior to that of the reference pipe body; if |Tx - T0| < 1 °C, it is determined that the heat insulation performance of the pipe to be tested meets the reference requirements.

[0084] In the test method of this embodiment, first test the reference pipe body, and use the test performance of the reference pipe body as the unified determination benchmark; then, test the heat insulation performance of the pipe to be tested under exactly the same test conditions, ensure the comparability of the detection data of the reference pipe body and the pipe to be tested, and achieve a rapid and accurate judgment of the overall heat insulation performance of the pipe to be tested.

[0085] This embodiment also discloses a test device for the heat insulation performance of pipes, which can be applicable to the test method of this embodiment. Refer to Figure 2, Figure 3 As shown, the device includes a test tube 1, a plug 2, a water pipe 3, a temperature sensor 4, a temperature recorder 5, a constant temperature water supply module, and a constant temperature environment chamber. There are two plugs 2, which can seal both ends of the test tube 1. The water pipe 3 includes an inlet pipe 31 and an outlet pipe 32, which are respectively connected to the corresponding plugs 2 and can communicate with the inside of the test tube 1, forming a circulating water circuit with the constant temperature water supply module.

[0086] There are n temperature sensors 4, specifically 5. They are arranged along the length of the pipe body 1 to be tested, and can collect the temperature data of the pipe body 1. Each temperature sensor 4 is electrically connected to the temperature recorder 5. In addition, the temperature recorder 5 is also electrically connected to the water temperature sensors on the inlet pipe 31 and the outlet pipe 32, so as to obtain the temperature of the inlet and outlet water ends, and thus to perform constant temperature monitoring of the circulating water.

[0087] Example 2

[0088] In the test steps of Example 1, the overall thermal insulation performance of the pipe body under test can be tested, and it can be determined whether the overall performance meets the thermal insulation standards. However, for high-performance and high-requirement applications, it is also necessary to ensure that the thermal insulation performance of each section of a single pipe body remains uniform and stable along its length, avoiding the creation of weak points in localized thermal insulation performance.

[0089] This embodiment discloses a method for testing the thermal insulation performance of pipes. Based on Embodiment 1, and further referring to... Figure 4 The following is a detailed description; this embodiment also includes the following steps: Step S6 Thermal insulation uniformity detection: Based on the steady-state temperature data of each detection position of the tube body to be tested obtained in step S4, the thermal insulation uniformity of each section of the tube body to be tested is evaluated.

[0090] Specifically, in step S6, the heat transfer coefficient Ki of the pipe segment between two adjacent sensors is calculated segment by segment. Based on the heat transfer coefficient Ki of each segment, the heat insulation uniformity coefficient U of the pipe body under test in the length direction is obtained. The heat insulation uniformity in the length direction of the pipe body is determined according to the coefficient U.

[0091] The heat transfer coefficient Ki of the pipe section between two adjacent sensors is:

[0092]

[0093] In the formula, c is the specific heat capacity of water at constant pressure; ρ is the density of water; q is the volumetric flow rate of circulating water; ΔTi is the fluid temperature drop of the i-th pipe segment, ΔTi=Tin-Tout; dm is the average diameter of the pipe insulation layer; d is the distance between adjacent sensors; ΔTm is the logarithmic mean temperature difference of the i-th pipe segment.

[0094] The thermal insulation uniformity coefficient U along the length of the tube to be tested is:

[0095]

[0096] In the formula, Kmin is the minimum heat transfer coefficient of all single pipe segments, and Kmax is the maximum heat transfer coefficient of all single pipe segments.

[0097] The uniformity of thermal insulation along the length of the pipe is determined by the coefficient U. If U ≥ 0.9, the thermal insulation performance along the length of the pipe is considered uniform. If 0.8 ≤ U < 0.9, the thermal insulation performance along the length of the pipe is considered basically uniform, with minor local defects. If U < 0.8, the thermal insulation performance along the length of the pipe is considered non-uniform, with obvious local defects.

[0098] This embodiment optimizes the steps of Embodiment 1, and can calculate the temperature parameters of each segment along the length of the pipe, thereby obtaining the thermal insulation performance parameters of each segment along the length of the pipe, and thus obtaining the uniformity of thermal insulation performance along the length of the pipe.

[0099] Example 3

[0100] This embodiment also discloses a method for testing the thermal insulation performance of pipes, which is based on Embodiment 2 and further refers to... Figure 5 , Figure 6 Please provide a detailed explanation.

[0101] In this embodiment, the plugs 2 at both ends of the pipe are piston-type plugs, which are connected to the piston of the pipe and can be adjusted along the length of the pipe to maintain a seal. The corresponding inlet pipe 31 and outlet pipe 32 are respectively connected to the corresponding plugs 2, and their ends extend into the circulation chamber of the pipe to realize circulating water guidance.

[0102] Before the test, the piston of the plug 2 can be adjusted, thereby adjusting the distance between the water inlet pipe 31 (i.e. the hot water inlet end) and the temperature sensor 4, and the pipe temperature at different positions (different positions are positions at different distances from the water inlet end) can be tested using the same temperature sensor 4.

[0103] The testing method in this embodiment is first executed according to the steps in the embodiment;

[0104] The test method in this embodiment also includes step S7 displacement calibration detection, which is used to improve the detection accuracy of heat insulation uniformity.

[0105] Specifically, step S7, displacement calibration detection, includes the following steps:

[0106] Step S7-1 Displacement Adjustment: Refer to Figure 3 , Figure 4As shown, keep the position of the tube to be tested fixed, and move the piston plugs at both ends synchronously in the same direction along the water flow direction, adjusting the distance to ΔL; or, keep the piston plugs at both ends fixed, and move the tube to be tested axially to adjust the relative position of the tube to be tested and the piston plugs.

[0107] Step S7-2 Steady-state test after displacement: Keep the test conditions completely consistent with steps S2 and S4, start the constant temperature water supply module until the system reaches thermal steady state, and collect the steady-state temperature data of each temperature sensor after displacement.

[0108] Step S7-3 Temperature estimation: Based on the friction temperature gradient Gx along the pipe body under test, obtain the theoretical temperature value of the same sensor after displacement. :

[0109] Tpi is the steady-state temperature value of the i-th sensor before displacement, Gx is the temperature gradient along the pipe body under test, and ΔL is the plug displacement adjustment amount.

[0110] Step S7-4 Temperature Deviation Calculation: Calculate the deviation between the theoretical temperature value and the actual measured value at the same detection location:

[0111] Tai is the actual steady-state measurement value of the i-th sensor after displacement;

[0112] The location of localized insulation defects in the pipe body is determined by ΔT. A preset threshold range ΔT0 for temperature deviation can be established. If the temperature deviation ΔT > ΔT0, it indicates that the above model has testing errors and the correlation coefficients in the model need to be corrected. The model can still locate the location of insulation performance defects in a certain section of the pipe body at that ΔT. If the temperature deviation ΔT ≤ ΔT0, it indicates that the above model meets the testing requirements and can obtain stable and accurate test performance parameters.

[0113] Step S7-5: Heat transfer coefficient correction:

[0114] The segmented heat transfer coefficient Ki obtained in step S6 is corrected based on the single-detection position deviation ΔT to obtain the corrected accurate heat transfer coefficient:

[0115] ΔTm is the logarithmic mean temperature difference of the corresponding pipe section.

[0116] In addition, step S7, displacement calibration detection, also includes the following steps:

[0117] Step S7-6: Correction of heat insulation uniformity:

[0118] The accurate thermal insulation uniformity coefficient along the length direction is calculated based on the corrected Ki':

[0119] Kmin' is the minimum value of the heat transfer coefficient of each segment after correction, and Kmax' is the maximum value of the heat transfer coefficient of each segment after correction. The uniformity parameter of the pipe length direction after correction is obtained through U'. The uniformity of the corrected U' is evaluated again to obtain the uniformity parameter situation after correction.

[0120] In this embodiment, by further optimizing the testing method in the above embodiment, the relative distance between the circulating hot water inlet and the temperature sensor can be adjusted by adjusting the relative positions of the pipe body and the piston plug. This adjustment can generate two sets of misaligned test data. The same two temperature sensors are misaligned in the pipe sections before and after adjustment. The two pipe sections are mutually optimized and compensated to further correct system errors and improve uniformity detection accuracy. By calculating the theoretical temperature Tti and the actual deviation ΔT, the heat transfer coefficient is corrected to obtain Ki' and the uniformity coefficient U', thus obtaining the final thermal insulation performance parameters. At the same time, the location of local thermal insulation defects can be located.

[0121] This embodiment also discloses a pipe insulation performance testing device, which is applicable to the testing method of this embodiment, and refers to... Figure 1 , Figure 2 As shown, the device includes a test tube 1, plugs 2, water pipes 3, a temperature sensor 4, a temperature recorder 5, a constant temperature water supply module, and a constant temperature environment chamber. There are two plugs 2, which can seal both ends of the test tube 1. The water pipe 3 includes an inlet pipe 31 and an outlet pipe 32, which are respectively connected to the two plugs 2 and can communicate with the inside of the test tube 1, forming a circulating water circuit with the constant temperature water supply module.

[0122] There are n temperature sensors 4, specifically 5. They are arranged along the length of the pipe body 1 to be tested, and can collect the temperature data of the pipe body 1. Each temperature sensor 4 is electrically connected to the temperature recorder 5. In addition, the temperature recorder 5 is also electrically connected to the water temperature sensors on the inlet pipe 31 and the outlet pipe 32, so as to obtain the temperature of the inlet and outlet water ends, and thus to perform constant temperature monitoring of the circulating water.

[0123] Reference Figure 7 , Figure 8 As shown, in accordance with the test method of this embodiment, the plug 2 is a piston-type plug. The piston-type plug is sealed and adapted to the inner circumference of the pipe body 1 to be tested, and can be adjusted along the length of the pipe body 1 to maintain a seal during the adjustment process. During the adjustment process, by sliding the piston-type plug, it remains in a sealed state throughout the adjustment process, thus maintaining a smooth circulating constant temperature water supply.

[0124] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for testing the thermal insulation performance of pipes, characterized in that, Including the steps: Step S1 Test condition preparation: Place the reference pipe body in a constant temperature environment, and arrange n temperature sensors equidistantly along the length direction in the middle section of the pipe body; Seal both ends of the pipe body with plugs, and connect both ends of the pipe body to a constant temperature water supply module respectively to form a circulating water path; Step S2 Calibration test of the reference pipe body: Keep the inlet water temperature and inlet water flow rate constant during the test. After reaching a steady state, obtain the steady state temperature values of each detection position through the temperature sensors; Step S3 Installation of the pipe body to be tested: Replace the reference pipe body in Step S1 with the pipe body to be tested; Step S4 Test of the pipe body to be tested: Keep the conditions the same as in Step S2, and test the pipe body to be tested; After reaching a steady state, obtain the steady state temperature values of each detection position through the temperature sensors; Step S5 Performance comparison and determination: Compare the steady state temperature data of the reference pipe body and the pipe body to be tested, and determine the overall heat insulation performance of the pipe body to be tested; Step S6 Detection of heat insulation uniformity: Based on the steady state temperature data of each detection position of the pipe body to be tested obtained in Step S4, obtain the heat insulation performance uniformity of each pipe section of the pipe body to be tested.

2. The method for testing the thermal insulation performance of pipes according to claim 1, characterized in that, In Step S2, after obtaining the steady state temperature value, obtain the average steady state temperature T0 of the reference pipe body as the reference for comparison and determination; In Step S4, after obtaining the steady state temperature value, calculate the average steady state temperature Tx of the pipe body to be tested.

3. The method for testing the thermal insulation performance of pipes according to claim 2, characterized in that, In Step S2, the inlet water temperature is controlled at 60°C to 90°C, and the control accuracy of the inlet water temperature is ±0.2°C; In Step S5, performance comparison and determination: If Tx < T0 and the difference between the two is ≥1°C, it is determined that the heat insulation performance of the pipe body to be tested is better than that of the reference pipe body; If Tx > T0 and the difference between the two is ≥1°C, it is determined that the heat insulation performance of the pipe body to be tested is inferior to that of the reference pipe body; If |Tx - T0| < 1°C, it is determined that the heat insulation performance of the pipe body to be tested meets the reference requirements.

4. The method for testing the thermal insulation performance of pipes according to claim 1, characterized in that, In Step S6, calculate the heat transfer coefficient Ki of the pipe section between two adjacent sensors one by one. Based on the heat transfer coefficient Ki of each section, obtain the heat insulation uniformity coefficient U in the length direction of the pipe body to be tested, and judge the heat insulation uniformity in the length direction of the pipe body according to the coefficient U; The heat transfer coefficient Ki of the pipe section between two adjacent sensors is: c is the specific heat capacity at constant pressure of water; ρ is the density of water; q is the volume flow rate of the circulating water; ΔTi is the temperature drop of the flowing water in the i-th pipe section, ΔTi = Tin - Tout, Tin is the inlet water temperature, Tout is the outlet water temperature; dm is the average diameter of the pipe insulation layer; d is the distance between adjacent sensors; ΔTm is the logarithmic mean temperature difference of the i-th pipe section; The heat insulation uniformity coefficient U in the length direction of the pipe body to be tested is: Kmin is the minimum value of the heat transfer coefficients of all single pipe sections, and Kmax is the maximum value of the heat transfer coefficients of all single pipe sections.

5. The method for testing the thermal insulation performance of pipes according to claim 4, characterized in that, If U ≥ 0.9, it is determined that the heat insulation performance in the length direction of the pipe body is uniform; If 0.8 ≤ U < 0.9, it is determined that the heat insulation performance in the length direction of the pipe body is basically uniform and there are local minor defects; If U < 0.8, it is determined that the heat insulation performance in the length direction of the pipe body is non-uniform and there are obvious local defects.

6. The method for testing the thermal insulation performance of pipes according to claim 1, characterized in that, Piston-type plugs are used at both ends of the pipe body to be tested. The piston-type plugs are piston-connected to the pipe body to be tested and can be adjusted along the length direction of the pipe body to be tested and maintain sealing; It also includes Step S7 Displacement calibration detection, which is used to improve the detection accuracy of heat insulation uniformity.

7. The method for testing the thermal insulation performance of pipes according to claim 6, characterized in that, The displacement calibration detection step S7 includes the following steps: Step S7-1 Displacement Adjustment: Keep the position of the tube to be tested fixed, and move the piston plugs at both ends synchronously in the same direction along the length, adjusting the distance to ΔL; Step S7-2 Steady-state test after displacement: Keep the test conditions completely consistent with steps S2 and S4, start the constant temperature water supply module until the system reaches thermal steady state, and collect the steady-state temperature data of each temperature sensor after displacement. Step S7-3 Temperature Calculation: Based on the friction temperature gradient Gx along the pipe body under test, obtain the theoretical temperature value of the same sensor after displacement. : Tpi is the steady-state temperature value of the i-th sensor before displacement, Gx is the temperature gradient along the pipe body under test, and ΔL is the plug displacement adjustment amount. Step S7-4 Temperature Deviation Calculation: Calculate the deviation between the theoretical temperature value and the actual measured value at the same detection location: Tai is the actual steady-state measurement value of the i-th sensor after displacement; Step S7-5: Heat transfer coefficient correction: The segmented heat transfer coefficient Ki obtained in step S6 is corrected based on the single-detection position deviation ΔT to obtain the corrected accurate heat transfer coefficient: ΔTm is the logarithmic mean temperature difference of the corresponding pipe section.

8. The method for testing the thermal insulation performance of pipes according to claim 7, characterized in that, The displacement calibration detection step S7 further includes the following steps: Step S7-6: Correction of heat insulation uniformity: The accurate thermal insulation uniformity coefficient along the length direction is calculated based on the corrected Ki': Kmin' is the minimum value of the heat transfer coefficient of each segment after correction, and Kmax' is the maximum value of the heat transfer coefficient of each segment after correction; the pipe length direction uniformity parameter after correction is obtained through U'; the location of local heat insulation defects in the pipe body is located through ΔT.

9. A device for testing the thermal insulation performance of pipes, characterized in that, The test tube includes (1), plug (2), water pipe (3), temperature sensor (4), temperature recorder (5), constant temperature water supply module and constant temperature environment chamber; The plug (2) is used to seal the two ends of the pipe body (1) to be tested; the water pipe (3) includes an inlet pipe (31) and an outlet pipe (32), the inlet pipe (31) and the outlet pipe (32) are respectively connected to the corresponding plug (2), and can communicate with the inside of the pipe body (1) to be tested, and are connected to the constant temperature water supply module to form a circulating water circuit; There are n temperature sensors (4) arranged along the length of the tube body (1) to be tested, which are used to collect the temperature data of the tube body (1). Each temperature sensor (4) is electrically connected to the temperature recorder (5). The temperature recorder (5) is also electrically connected to the water temperature sensors on the inlet pipe (31) and the outlet pipe (32) to obtain the inlet and outlet water temperatures. The thermal insulation performance of the pipe body (1) to be tested is tested using the pipe insulation performance test method as described in any one of claims 1-8.

10. A pipe insulation performance testing device according to claim 9, characterized in that, The plug (2) is a piston plug. The piston plug is adapted to the inner circumference of the tube body (1) to be tested and can be adjusted along the length of the tube body (1) to be tested, maintaining a seal during the adjustment process.

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