Process method for installing ferrule type joint pipeline of urban railway vehicle braking system

Abstract

The invention relates to the technical field of urban railway vehicles, in particular to an urban railway vehicle brake system clamping sleeve type connector pipe fitting installation process method which comprises the steps that clamping sleeves are installed on a pipe fitting according to working preassembling values corresponding to the clamping sleeves of different manufacturers and different diameters, and the installation positions of brake equipment and a brake valve body are obtained; installing and fixing the braking equipment at the obtained installation position; the pipe fitting provided with the clamping sleeve is fixed; a pipe fitting is connected from the braking equipment end to the pipe row piping; the connector and the pipe fitting are pre-installed to ensure that the axis of the connector and the axis of the pipe fitting are collinear; adjusting the pipe fitting to ensure that the pipe fitting is vertical and / or horizontal, and fixing the pipe fitting by a pipe clamp to fix the arrangement position of the pipe fitting; and the pipe fitting and the connector are pressed and fastened. By means of the method, the working preassembling force is obtained for the clamping sleeves of different manufacturers and different diameters, the same clamping sleeve can be preassembled on the pipe fitting through the same working preassembling force, and then the installation efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of urban rail vehicle technology, and in particular to a method for installing a compression fitting type pipe in the braking system of urban rail vehicles. Background Technology

[0002] In the rail transit manufacturing industry, compression fittings are commonly used for connecting the piping of locomotive and rolling stock braking systems. Before formal assembly, a compression fitting pre-installation machine is typically used to pre-install the compression fitting, nut, and pipe fitting, followed by formal installation with the corresponding connector. The pipe connection installation process achieves a sealed connection by applying a certain tightening torque to the connector nut. The pre-installation process involves the same forces as the pipe connection installation process; the only difference is that the compression fitting is pre-inserted into the pipe. In related technologies, after compression fitting pre-installation, air leakage may occur during the formal connector assembly process, or excessive tightening torque may be applied during installation to avoid leakage. Therefore, selecting an appropriate pre-installation force for the compression fitting can reduce the tightening torque value during the formal assembly process or the inconvenience caused by pipe replacement, thereby improving the efficiency of the installation operation.

[0003] Compression fittings produced by different manufacturers vary in hardness, structural dimensions, etc. (without considering the differences in hardness and dimensions of the pipe fittings being pressed). Therefore, the selection of pre-installation force will also differ when pre-installing compression fittings of the same pipe diameter from different brands. Summary of the Invention

[0004] In one aspect, the present invention provides a method for installing a compression fitting pipe in a braking system of urban rail vehicles, which can improve the pre-installation force and connect the pipe according to the compression fittings provided by different manufacturers, thereby improving assembly efficiency.

[0005] According to one aspect of the present invention, a method for installing a compression fitting pipe in a braking system of an urban rail vehicle is provided, the method comprising the following steps:

[0006] S101. Install the ferrule onto the pipe fitting according to the working pre-installation value corresponding to the ferrule of different manufacturers and different diameters;

[0007] S102. Obtain the installation position of the braking device and the brake valve body, and install and fix the braking device at the obtained installation position;

[0008] S103. Secure the pipe fitting with the ferrule installed;

[0009] S104. Connecting pipe fittings from the braking device end to the pipe bank;

[0010] S105. Pre-install the joints and fittings to ensure that the axis of the joints and the axis of the fittings are collinear;

[0011] S106. Adjust the pipe fittings to ensure that they are vertical and / or horizontal, and fix the pipe fittings with pipe clamps to fix their positions.

[0012] S107. Press-fit and tighten the pipe fittings and joints.

[0013] As an optional technical solution for the installation process of the ferrule-type connector pipeline in the above-mentioned urban rail vehicle braking system, the working pre-installation force corresponding to ferrules of different manufacturers and diameters is obtained in the following way:

[0014] S1011. Press the ferrule according to the reference base pre-installation value of the ferrule pre-installation machine;

[0015] S1012. Visually inspect the raised portion of the pipe fittings at the cutting edge of the ferrule, the shape of the pipe fitting opening, and whether the ferrule can move. The movement includes circumferential rotation of the ferrule along the axial direction and / or back-and-forth movement along the axial direction.

[0016] S1013. Based on the information obtained from the visual inspection in step S1012, quantitatively reduce and increase the basic pre-installed value to obtain the first intermediate pre-installed value and the second intermediate pre-installed value.

[0017] S1014. Pre-install pipe fittings of different diameters using the basic pre-installation value, the first intermediate value, and the second intermediate value, and perform a tightening torque test on the pre-installed pipe fittings. During the tightening torque test, different tightening torques are used to tighten pipe fittings of the same diameter to obtain the working pre-installation value of the pipe fitting that does not leak under the lowest torque. Each time tightening is performed, the joint and the pipe fitting are in a loose state. The initial value of the tightening torque is the torque value corresponding to the pipe fitting rotating 1 / 2 turn after the torque surge point during tightening.

[0018] As an optional technical solution for the above-mentioned installation process of the compression fitting pipe of the braking system of urban rail vehicles, the information obtained by visual inspection includes: good pre-installation effect of the pipe fitting, the pipe fitting is broken at the raised part of the compression fitting edge, the raised part of the pipe fitting at the compression fitting edge is uneven, or the pipe end of the pipe fitting is bulging.

[0019] As an optional technical solution for the above-mentioned installation process of the compression fitting pipe of the urban rail vehicle braking system, the quantitative reduction or increase of the pre-installation force based on the information obtained from the visual inspection in step S1012 includes:

[0020] Visual inspection showed the pre-installation effect was good. Pre-set pressure was increased and decreased based on the existing basic pre-installation value to obtain a first intermediate pre-installation value and a second intermediate pre-installation value for tightening torque testing; or,

[0021] If the pipe fitting's nozzle expands, the pre-installation force is reduced and updated. The ferrule and fitting are then reassembled based on the updated pre-installation force until no obvious expansion is visually observed. This yields the revised basic pre-installation value. Based on this revised basic pre-installation value, quantitative reductions and increases are made to obtain the first and second intermediate pre-installation values; or...

[0022] If the cutting depth of the connector's cutting edge is less than the preset value, the fitting breaks off at the raised part of the ferrule's cutting edge, or the raised part of the fitting is uneven, then the pre-installation force is increased and updated. The ferrule and fitting are reassembled according to the updated pre-installation force until the cutting edge embedding depth is visually inspected to be uniform, so as to obtain the modified basic pre-installation value. Based on the modified basic pre-installation value, the pre-installation value is quantitatively reduced and increased to obtain the first intermediate pre-installation value and the second intermediate pre-installation value.

[0023] As an optional technical solution for the above-mentioned installation process of the compression fitting pipe of the urban rail vehicle braking system, during the tightening torque test, different tightening torques are used to tighten the pipe fittings of the same diameter to obtain the pre-installation value of the pipe fitting that does not leak under the lowest torque. The working pre-installation value includes the following steps:

[0024] Compare the leakage of pipe fittings with the same pipe diameter but different working pre-installation values. If the leakage is the same, reduce and update the test torque value. Based on the updated test torque value, tighten the ferrule to the pipe fittings with the same pipe diameter but different working pre-installation values ​​and then conduct an airtightness test. Select the pre-installation value corresponding to the minimum tightening torque for the same pipe diameter without leakage as the working pre-installation value.

[0025] As an optional technical solution for the above-mentioned installation process of the ferrule-type connector pipeline of the urban rail vehicle braking system, if the difference between the ferrule cone angle and the inner cone angle of the pipe joint obtained after pre-installing the ferrule and the pipe fitting with the determined working pre-installation value is greater than the preset difference, then a bushing is installed on the outer sleeve of the pipe fitting during the pipe fitting assembly process, or the pipe fitting wall thickness is increased.

[0026] As an optional technical solution for the above-mentioned installation process of the compression fitting pipe of the urban rail vehicle braking system, the following steps are included before step S105:

[0027] Cleaning and protection of brake lines.

[0028] As an optional technical solution for the above-mentioned installation process of the ferrule-type connector pipeline of the urban rail vehicle braking system, after press-fitting and tightening, the following steps are also included: S107, conducting a wind pressure test on the assembled brake pipeline.

[0029] As an optional technical solution for the above-mentioned installation process of the compression fitting pipe of the urban rail vehicle braking system, the wind pressure test includes the following steps:

[0030] The wind pressure test includes the following steps:

[0031] S1071. Connect the external air source from the main air cylinder, and seal the installation process pipe plug or process cut-off valve of the main air pipe and the parking pipe and brake pipe at the end of the pipeline system at the vehicle end; cut off the air spring tube and do not charge the vehicle air spring port with air first.

[0032] S1072, Total working pressure of the vehicle's air supply to the upper limit;

[0033] S1073. First, open the main air process pipe plug or process cut-off valve at one end to exhaust air for a first preset time. After exhausting, seal the pipe. Then exhaust air at the other end and reseal it. Next, exhaust air and reseal the brake pipe and parking pipe in sequence. After checking the main air pipe, brake pipe, and parking pipe, charge and exhaust air into the air spring ports one by one. After a second preset time, seal the ports using the process plug or process cut-off valve.

[0034] S1074. After the vehicle inflation pressure stabilizes at the upper limit, apply soapy water to the pipe joints and test for leaks.

[0035] S1075. When a leak is found, observe whether the pipeline is bent. If it is bent, adjust it to release stress and ensure that the fitting is coaxial with the joint after being inserted to the bottom of the connector. If there is no bend, use a wrench to increase the torque between the connector and the fitting to tighten it.

[0036] S1076. After the pressure holding test meets the requirements, remove the process plug and restore the relevant pipeline connections.

[0037] As an optional technical solution for the above-mentioned installation process of the compression fitting pipe of the urban rail vehicle braking system, the following steps are also included before performing step S101:

[0038] S1011. Perform visual inspection and cleaning of pipe fittings.

[0039] The above technical solution has at least the following advantages or beneficial effects:

[0040] By obtaining the working pre-installation force for ferrules of different manufacturers and diameters using the above method, the same ferrules can be pre-installed on pipe fittings with the same working pre-installation force, thereby improving installation efficiency. Furthermore, it allows ferrules from different manufacturers to obtain corresponding working pre-installation forces, which can improve installation effect and reduce rework rate. Attached Figure Description

[0041] Figure 1 This is a flowchart of the installation process of the compression fitting pipe of the braking system of urban rail vehicles in an embodiment of the present invention. Detailed Implementation

[0042] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0043] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions. Furthermore, "above," "on top of," and "over" the first feature in relation to the second feature includes the first feature directly above and diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "under," and "below" the first feature in relation to the second feature includes the first feature directly below and diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0044] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0045] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0046] like Figure 1 This embodiment provides a method for installing a compression fitting pipe in the braking system of an urban rail vehicle. The method includes the following steps:

[0047] S101. Install the ferrule onto the pipe fitting according to the working pre-installation value corresponding to the ferrule of different manufacturers and different diameters;

[0048] S102. Obtain the installation position of the braking device and the brake valve body, and install and fix the braking device at the obtained installation position;

[0049] S103. Secure the pipe fitting with the ferrule installed;

[0050] S104. Connecting pipe fittings from the braking device end to the pipe bank;

[0051] S105. Pre-install the joints and fittings to ensure that the axis of the joints and the axis of the fittings are collinear;

[0052] Before connecting pipe fittings and connectors, apply appropriate amounts of grease for lubrication;

[0053] S106. Adjust the pipe fittings to ensure that they are vertical and / or horizontal, and fix the pipe fittings with pipe clamps to fix their positions.

[0054] S107. Press-fit and tighten the pipe fittings and joints.

[0055] The present invention provides a method for installing a compression fitting pipe in a braking system for urban rail vehicles. First, the compression fitting is installed on the pipe according to the working pre-assembly value corresponding to different manufacturers and different diameters. Then, after fixing the pipe fitting, the fitting body and the pipe fitting are press-fitted and tightened. This method can be applied to different compression fittings to meet the assembly needs of the compression fitting and the pipe fitting, thereby improving the assembly efficiency.

[0056] In some embodiments, the working preload force corresponding to ferrules of different manufacturers and diameters is obtained in the following manner:

[0057] S1011. Press the ferrule according to the reference base pre-installation value of the ferrule pre-installation machine;

[0058] S1012. Visually inspect the raised portion of the pipe fittings at the cutting edge of the ferrule, the shape of the pipe fitting opening, and whether the ferrule can move. The movement includes circumferential rotation of the ferrule along the axial direction and / or back-and-forth movement along the axial direction.

[0059] S1013. Based on the information obtained from the visual inspection in step S1012, quantitatively reduce and increase the basic pre-installed value to obtain the first intermediate pre-installed value and the second intermediate pre-installed value.

[0060] For example, based on the base pre-installed value, each time an additional 5 Bar or 10 Bar is added to assign a value to the pre-installed value.

[0061] S1014. Pre-install pipe fittings of different diameters using the basic pre-installation value, the first intermediate value, and the second intermediate value, and perform a tightening torque test on the pre-installed pipe fittings. During the tightening torque test, different tightening torques are used to tighten pipe fittings of the same diameter to obtain the working pre-installation value of the pipe fitting that does not leak under the lowest torque. Each time tightening is performed, the joint and the pipe fitting are in a loose state. The initial value of the tightening torque is the torque value corresponding to the pipe fitting rotating 1 / 2 turn after the torque surge point during tightening.

[0062] The torque surge point refers to the point where a noticeable change in torque is felt during the process of inserting the pre-installed pipe into the connector and tightening the nut. The recommended personnel and wrench length for tightening the nut can be roughly referenced in the table below:

[0063]

[0064] By obtaining the working pre-installation force for ferrules of different manufacturers and diameters using the above method, the same ferrules can be pre-installed on pipe fittings with the same working pre-installation force, thereby improving installation efficiency. Furthermore, it allows ferrules from different manufacturers to obtain corresponding working pre-installation forces, which can improve installation effect and reduce rework rate.

[0065] The above limitations allow for a better working pre-installation value at a lower tightening torque, thereby ensuring the optimal pre-installation force for the connection between the fitting and the ferrule and reducing the risk of leakage.

[0066] In some embodiments, the information obtained from visual inspection includes: the fitting is well pre-installed, the fitting is broken at the bulging part of the ferrule edge, the fitting is uneven at the bulging part of the ferrule edge, or the fitting end is bulging.

[0067] The good pre-assembly effect of the pipe fittings means that the pre-assembly effect of the pipe fittings and the ferrule meets the requirements. Specifically, the pipe fittings are not broken at the raised part of the ferrule blade edge, the raised part of the pipe fittings at the ferrule blade edge is uniform, and there is no bulging at the pipe end of the pipe fittings. The purpose of visual inspection is to ensure that the ferrule and the pipe fittings are well connected and to avoid subsequent pipeline connection failures due to the non-compliance of the structure of either the ferrule or the pipe fittings.

[0068] In some embodiments, quantitatively reducing or increasing the pre-loading force based on the information obtained from the visual inspection in step S1012 includes:

[0069] Visual inspection showed that the pre-installation effect was good. The preset pressure was increased and decreased respectively based on the existing basic pre-installation value to obtain the first intermediate pre-installation value and the second intermediate pre-installation value for tightening torque testing.

[0070] Alternatively, if the pipe fitting has an bulging end, the pre-installation force is reduced and updated. The ferrule and pipe fitting are then reassembled based on the updated pre-installation force until the pipe fitting is visually inspected and no obvious bulging end is found. This is to obtain the modified basic pre-installation value. The modified basic pre-installation value is then quantitatively reduced and increased to obtain the first intermediate pre-installation value and the second intermediate pre-installation value.

[0071] Alternatively, if the cutting depth of the connector's cutting edge is less than the preset value, the fitting breaks off at the raised part of the ferrule's cutting edge, or the raised part of the fitting is uneven, then the pre-installation force is increased and updated. The ferrule and fitting are then reassembled based on the updated pre-installation force until the cutting edge embedding depth is visually inspected to be uniform, so as to obtain the modified basic pre-installation value. Based on the modified basic pre-installation value, the pre-installation value is quantitatively reduced and increased to obtain the first intermediate pre-installation value and the second intermediate pre-installation value.

[0072] For example, if the visual inspection shows a good pre-assembly result, increase the preset pressure based on the existing pre-assembly value and then decrease the preset pressure for testing, thereby obtaining fittings and ferrules with at least three pre-assembly values ​​for pressing. Repeat the above visual pre-assembly inspection and observe the pressing effect. Specifically, if the visual inspection shows a good pre-assembly result, increase the pressure by 5 Bar and decrease it by 5 Bar based on the existing pre-assembly value for testing, and continue to repeat the above visual pre-assembly inspection.

[0073] For example, if the pipe fitting's nozzle bulges, the pre-installation force should be reduced and updated. Each update should be less than the base pre-installation force to prevent excessive force from causing nozzle bulging and deformation. For instance, if the recommended pre-installation force appears too high upon visual inspection, resulting in nozzle bulging, the pre-installation force should be reduced by 5 Bar sequentially until no obvious bulging is visually observed. This process should be repeated, and then, based on this pre-installation value, pressure fitting should be performed with reductions of 5 Bar and 10 Bar, with three fittings pre-installed at each pressure, and the effect observed.

[0074] For example, if the cutting depth of the fitting's cutting edge is less than the preset value (e.g., 0.25mm), the fitting breaks off at the raised part of the ferrule's cutting edge, or the raised part of the fitting is uneven, then the pre-installation force is increased and updated. The ferrule and fitting are then reassembled based on the updated pre-installation force until the cutting edge embedding depth is visually inspected as uniform. Specifically, if the visual inspection shows the cutting depth is too small, insufficient, or the cutting edge bulge is intermittent or uneven, the pre-installation force is increased by 5 Bar sequentially until the cutting edge embedding depth is visually inspected as uniform. Based on this, an additional 5 Bar and then 10 Bar are sequentially added for pressing, and the pressing effect is observed.

[0075] In some embodiments, the fitting and ferrule are tightened with a test torque less than or equal to the test torque value, and the tightening is performed at least twice. The test torque at the last tightening is the test torque value. After each tightening, an airtightness test is performed on the connection position between the fitting and the ferrule, and the leakage is observed and compared. The first intermediate value used for the fitting with the smallest leakage is selected as the working pre-installation value. This includes the following steps:

[0076] Tighten the ferrule to the fittings of the same diameter but different working pre-installation values ​​with a test torque equal to the test torque value, and then perform an airtightness test on the tightened fittings and record the leakage.

[0077] Compare the leakage of pipe fittings with the same pipe diameter but different working pre-installation values. If the leakage is the same, reduce and update the test torque value. Based on the updated test torque value, tighten the ferrule to the pipe fittings with the same pipe diameter but different working pre-installation values ​​and then conduct an airtightness test. If the leakage is the same, continue to reduce and update the test torque value until a clear difference in leakage occurs, so as to select the appropriate working pre-installation value with good sealing performance.

[0078] In some embodiments, if the difference between the cone angle of the ferrule and the inner cone angle of the pipe joint after pre-installing the ferrule and the pipe fitting with the determined working pre-installation value is greater than the preset difference, then a bushing is installed on the outer sleeve of the pipe fitting during the pipe fitting assembly process, or the pipe fitting wall thickness is increased.

[0079] The purpose of installing a bushing on the outer sleeve of the critical fitting is to increase the local thickness of the fitting, thereby increasing its local strength. Alternatively, it can be achieved by increasing the overall wall thickness of the fitting, thus improving its overall strength. This ensures that the ferrule and the pipe fitting fit together as closely as possible after installation.

[0080] In some embodiments, before step S105, the following steps are further included:

[0081] Cleaning and protection of brake lines.

[0082] Specifically, after the pre-installation inspection of the pipe fittings, the fittings need to be purged using clean, dry air at a pressure of not less than 600 kPa; or the fittings can be treated with a sponge to ensure the pipeline is clean. Protective plugs should be placed on both ends of the cleaned pipeline.

[0083] In some embodiments, after press-fitting and fastening, the following steps are further included: S107, performing a wind pressure test on the assembled brake pipeline.

[0084] In some embodiments, the wind pressure test includes the following steps:

[0085] S1071. Connect the external air source from the main air cylinder, and seal the installation process pipe plug or process cut-off valve of the main air pipe and the parking pipe and brake pipe at the end of the pipeline system at the vehicle end; cut off the air spring tube and do not charge the vehicle air spring port with air first.

[0086] S1072, Total working pressure of the vehicle's air supply to the upper limit;

[0087] S1073. Open the main air process pipe plug or process cut-off valve at one end to exhaust air for the first preset time. After exhausting air, reseal the pipe. Then exhaust air at the other end and reseal the pipe. Next, exhaust air and reseal the brake pipe and parking pipe in sequence. After checking the main air pipe, brake pipe, and parking pipe, charge and exhaust air into the air spring ports one by one. After the second preset time, reseal the pipe using the process plug or process cut-off valve.

[0088] S1074. After the vehicle is charged to the upper limit pressure, apply soapy water to the pipe joints and test for leaks. During this process, listen for any obvious air leaks and check for cracks or leaks in the pipes.

[0089] S1075. When a leak is found, observe whether the pipeline is bent. If it is bent, adjust it to release stress and ensure that the fitting is coaxial with the joint after being inserted to the bottom of the connector. If there is no bend, use a wrench to increase the torque between the connector and the fitting to tighten it.

[0090] If the problem cannot be fixed after increasing the torque, loosen the joint and check if the fitting is faulty or overtightened. If the fitting is faulty, replace the fitting. If there is no obvious abnormality, try to retighten it. If the problem cannot be fixed after applying the maximum recommended tightening torque, disassemble, adjust or replace the fitting.

[0091] S1076. After the pressure test meets the requirements, remove the process plug and restore the relevant pipe connections.

[0092] The purpose of the air pressure test is to check the quality of the assembly between the ferrule and the pipe fitting, so as to ensure that the pipe fitting can work normally and that there is no air leakage.

[0093] Before executing S1071, the following steps are also included:

[0094] Tighten the critical pipe clamps for final tightening;

[0095] Apply process plugs to protect the exposed pipe joints after installation.

[0096] In some embodiments, before performing step S101, the following steps are further included:

[0097] S1011. Perform visual inspection and cleaning of pipe fittings.

[0098] First, perform a visual inspection of the pipe fittings. The outer surface of the fittings should be free of defects that could affect the ferrule seal. For example, starting 20mm from the pipe end, the circumferential surface of the fitting should be free of unevenness exceeding 50% of the fitting diameter tolerance. Pipe fittings should be cut using a serrated cutting method; pipe cutters, cutting wheels, or similar tools should not be used. The perpendicularity deviation between the pipe end face and the fitting should be less than ±0.5°.

[0099] After visual inspection, the fittings need to be cleaned. To ensure the safe use of the braking system, a missile tool is used for cleaning, and the cleanliness of the inside of the fittings is checked. For example, the particle size of the debris should not exceed 10μm. Cleaning measures must be taken during transportation and installation. Before assembly, the fittings should be cleaned with high-pressure air to remove oil, varnish, or other impurities from the outer surface of the fitting ends. Assembly is only permitted after visual inspection to ensure there is no debris or rust.

[0100] This invention describes the selection method for the pre-installation value of ferrule fittings from the perspectives of process flow and operation. Selecting a pre-installation value with relatively good effect can improve the quality of pre-installed ferrules, extend the service life of ferrules, avoid waste, reduce the tightening torque value, improve production efficiency, and help improve the reliability of pipeline installation.

[0101] Meanwhile, a systematic method for the installation and testing of compression fittings and pipelines is described, which can systematically guide the relevant operations of pipeline installation and testing. The method is advanced and has good applicability. Applying this method to purge before the wind pressure test can also check whether there are foreign objects blocking the pipeline in the system, ensuring the safety and reliability of the braking system.

[0102] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for installing a compression fitting type pipe in the braking system of urban rail vehicles, characterized in that, Includes the following steps: S101. Install the ferrule onto the pipe fitting according to the working pre-installation value corresponding to the ferrule of different manufacturers and different diameters; S102. Obtain the installation position of the braking device and the brake valve body, and install and fix the braking device at the obtained installation position; S103. Secure the pipe fitting with the ferrule installed; S104. Connecting pipe fittings from the braking device end to the pipe bank; S105. Pre-install the joints and fittings to ensure that the axis of the joints and the axis of the fittings are collinear; S106. Adjust the pipe fittings to ensure that they are vertical and / or horizontal, and fix the pipe fittings with pipe clamps to fix their positions. S107. Press-fit and tighten the pipe fittings and joints.

2. The installation process of the compression fitting type connector pipeline for the braking system of urban rail vehicles according to claim 1, characterized in that, The pre-loading force for ferrules of different manufacturers and diameters is obtained in the following way: S1011. Press the ferrule according to the reference base pre-installation value of the ferrule pre-installation machine; S1012. Visually inspect the raised portion of the pipe fittings at the cutting edge of the ferrule, the shape of the pipe fitting opening, and whether the ferrule can move. The movement includes circumferential rotation of the ferrule along the axial direction and / or back-and-forth movement along the axial direction. S1013. Based on the information obtained from the visual inspection in step S1012, quantitatively reduce and increase the basic pre-installed value to obtain the first intermediate pre-installed value and the second intermediate pre-installed value. S1014. Pre-install pipe fittings of different diameters using the basic pre-installation value, the first intermediate value, and the second intermediate value, and perform a tightening torque test on the pre-installed pipe fittings. During the tightening torque test, different tightening torques are used to tighten pipe fittings of the same diameter to obtain the working pre-installation value of the pipe fitting that does not leak under the lowest torque. Each time tightening is performed, the joint and the pipe fitting are in a loose state. The initial value of the tightening torque is the torque value corresponding to the pipe fitting rotating 1 / 2 turn after the torque surge point during tightening.

3. The installation process of the compression fitting type connector pipeline for the braking system of urban rail vehicles according to claim 2, characterized in that, The information obtained from the visual inspection includes: the pipe fitting is well pre-installed; the pipe fitting is broken at the raised part of the ferrule edge; the raised part of the pipe fitting at the ferrule edge is uneven; or the pipe fitting opening is bulging.

4. The installation process of the compression fitting type connector pipeline for the braking system of urban rail vehicles according to claim 3, characterized in that, Based on the information obtained from the visual inspection in step S1012, quantitatively reducing or increasing the pre-loading force includes: Visual inspection showed the pre-installation effect was good. Pre-set pressure was increased and decreased based on the existing basic pre-installation value to obtain a first intermediate pre-installation value and a second intermediate pre-installation value for tightening torque testing; or, If the pipe fitting's nozzle expands, the pre-installation force is reduced and updated. The ferrule and fitting are then reassembled based on the updated pre-installation force until no obvious expansion is visually observed. This yields the revised basic pre-installation value. Based on this revised basic pre-installation value, quantitative reductions and increases are made to obtain the first and second intermediate pre-installation values; or... If the cutting depth of the connector's cutting edge is less than the preset value, the fitting breaks off at the raised part of the ferrule's cutting edge, or the raised part of the fitting is uneven, then the pre-installation force is increased and updated. The ferrule and fitting are reassembled according to the updated pre-installation force until the cutting edge embedding depth is visually inspected to be uniform, so as to obtain the modified basic pre-installation value. Based on the modified basic pre-installation value, the pre-installation value is quantitatively reduced and increased to obtain the first intermediate pre-installation value and the second intermediate pre-installation value.

5. The installation process of the compression fitting type connector pipeline for the braking system of urban rail vehicles according to claim 2, characterized in that, During the tightening torque test, different tightening torques are used to tighten pipe fittings of the same diameter to obtain the pre-installation value of the pipe fitting that does not leak under the lowest torque. The pre-installation value includes the following steps: Compare the leakage of pipe fittings with the same pipe diameter but different working pre-installation values. If the leakage is the same, reduce and update the test torque value. Based on the updated test torque value, tighten the ferrule to the pipe fittings with the same pipe diameter but different working pre-installation values ​​and then conduct an airtightness test. Select the pre-installation value corresponding to the minimum tightening torque for the same pipe diameter without leakage as the working pre-installation value.

6. The installation process of the compression fitting type connector pipeline for the braking system of urban rail vehicles according to claim 2, characterized in that, If, after using the determined working pre-installation values ​​to pre-install the ferrule and fittings, the difference between the ferrule cone angle and the inner cone angle of the pipe joint is greater than the preset difference, then a bushing should be installed on the outer sleeve of the fitting during the fitting assembly process, or the wall thickness of the fitting should be increased.

7. The installation process of the compression fitting type connector pipeline for the braking system of urban rail vehicles according to claim 1, characterized in that, Before step S105, the following steps are also included: Cleaning and protection of brake lines.

8. The installation process of the compression fitting type connector pipeline for the braking system of urban rail vehicles according to claim 1, characterized in that, After press-fitting and tightening, the following steps are also included: S107, conduct a wind pressure test on the assembled brake pipeline.

9. The installation process of the compression fitting type connector pipeline for the braking system of urban rail vehicles according to claim 8, characterized in that, The wind pressure test includes the following steps: S1071. Connect the external air source from the main air cylinder, and seal the installation process pipe or process cut-off valve of the main air pipe and the parking pipe and brake pipe at the end of the pipeline system at the vehicle end. Cut the air spring tube and do not charge the vehicle's air spring inlet with air first; S1072, Total working pressure of the vehicle's air supply to the upper limit; S1073. Open the main air process pipe plug or process cut-off valve at one end to exhaust air for the first preset time. After exhausting air, reseal the pipe. Then exhaust air at the other end and reseal the pipe. Next, exhaust air and reseal the brake pipe and parking pipe in sequence. After checking the main air pipe, brake pipe, and parking pipe, charge and exhaust air into the air spring ports one by one. After the second preset time, reseal the pipe using the process plug or process cut-off valve. S1074. After the vehicle inflation pressure stabilizes at the upper limit, apply soapy water to the pipe joints and test for leaks. S1075. When a leak is found, observe whether the pipe fitting is bent. If it is bent, adjust it to release stress and ensure that the pipe fitting and the joint are coaxial after the pipe fitting is inserted to the bottom of the joint. If it is not bent, use a wrench to increase the torque between the joint and the pipe fitting to tighten it. S1076. After the pressure test meets the requirements, remove the process plug and restore the pipe connection.

10. The installation process of the compression fitting type connector pipeline for the braking system of urban rail vehicles according to claim 1, characterized in that, Before performing step S101, the following steps are also included: S1011. Perform visual inspection and cleaning of pipe fittings.

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