A bellows waveform testing device and a testing method

Abstract

The present invention discloses a bellows waveform testing device, which is characterized in that: it includes a base, on which a rotating mounting plate for mounting a test piece is provided, and a bracket with a track is also provided on the base. Above the bracket, a lifting motor with a lead screw is provided. The lead screw cooperates with a servo cylinder slidably connected to the track. A high-speed camera is provided on the cylinder body of the servo cylinder, and a ranging sensor cooperating with the test piece is provided at the movable end of the servo cylinder. The structure of the present invention can effectively solve the cumbersome work of multiple manual clamping, measurement, and recording in the high-frequency waveform testing work of bellows by current bellows production enterprises and relevant testing institutions. The measurement and recording processes are all automatically completed by the device, changing the influence of manual measurement by different people with different measuring tools on the measurement results, and realizing efficient, accurate, and stable measurement of the bellows waveform.

Description

Technical Field

[0001] The present invention belongs to the technical field of bellows testing equipment, and particularly relates to a bellows waveform testing device and a testing method for measuring the waveform change of a bellows under pressure. Background Art

[0002] An expansion joint is a compensating element that uses the telescopic deformation of a bellows to absorb the dimensional change of a pipeline. The waveform size of the bellows and the change of the waveform under pressure are important parameters for determining whether the expansion joint is qualified.

[0003] The existing measurement of the bellows waveform mainly uses manual marking of wave peaks and multiple manual repeated measurements and records with a caliper, etc. The human factor has a great influence on the measurement result. Even if an optical measurement method is adopted, it cannot solve the problem of identifying the change distance after the original wave peak point of the bellows shifts under pressure, resulting in deviation of the measurement result and inability to accurately reflect the performance index of the bellows. Summary of the Invention

[0004] The purpose of the present invention is to provide a bellows waveform testing device and a testing method to solve the existing problems.

[0005] The present invention is realized through the following technical solutions: A bellows waveform testing device, characterized in that: it includes a base, on which a rotary mounting plate for mounting a test piece is provided, and a bracket with a track is also provided on the base. Above the bracket, a lifting motor with a lead screw is provided. The lead screw is matched with a servo cylinder sliding on the track, and a distance measuring sensor and a high-speed camera matched with the test piece are provided on the servo cylinder.

[0006] The present invention also discloses a bellows waveform testing method using the above device, characterized in that: it includes the following steps,

[0007] S1, vertically install the test piece on the rotary table,

[0008] S2, according to the nominal diameter of the test piece, the servo cylinder adjusts the focal distance of the laser distance measurement, inputs the measured length of the test piece, and the vertical servo drives the measuring device to move to the top of the test piece. The servo starts to move slowly downward from the top to find the minimum and maximum distances, which are the wave peak and wave valley, and mark them;

[0009] S3, when running to the bottom of the device, the marking ends, and at the same time, the laser measurement data and the vertical servo data in the whole process are combined to generate an initial waveform curve;

[0010] S4, after the test piece is subjected to other tests, reinstall the test piece,

[0011] S5, the lifting motor runs, driving the servo electric cylinder to move from top to bottom. The mark position is identified by the high-speed camera and fed back to the distance measurement sensor. The data of the vertical movement of the servo electric cylinder when the feedback signal is generated is collected and compared with the previous measurement data to calculate the wave pitch change rate.

[0012] The advantages of the present invention are: the structure of the present invention can effectively solve the complicated work of multiple manual clamping, measurement and recording in the high-frequency waveform testing of bellows by bellows manufacturers and related testing institutions. The measurement and recording process is completed automatically by the equipment, which changes the influence of different people and different inspection tools on the measurement results in the past manual measurement, and realizes efficient, accurate and stable measurement of the bellows waveform. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0014] Explanation of the serial numbers in the figure: 1-lifting motor; 2-distance sensor; 3-servo electric cylinder; 4-high-speed camera; 5-screw; 6-rotating mounting plate; 7-rotating motor; 8-base; 9-track. DETAILED DESCRIPTION

[0015] like Figure 1 The figure shows a corrugated pipe waveform testing device of the present invention, including a base 8, a rotating mounting plate 6 is arranged on the base, a rotating shaft is arranged at the lower part of the rotating mounting plate, the rotating shaft and the base are matched through bearings, the rotating shaft passes through the upper surface of the base and matches with the rotating motor 7 arranged inside the base and is driven to rotate, and a fixed structure such as a flange hole is arranged on the rotating mounting plate to match with the test piece to be tested; a bracket is also fixed on the base, a track 9 is vertically arranged on the bracket, and a lifting motor 1 with a lead screw 5 is arranged above the bracket, the lead screw is matched with a servo electric cylinder 3 sliding on the track, a distance sensor 2 matching with the test piece to be tested is arranged on the free end of the servo electric cylinder, and a high-speed camera 4 is arranged on the lower side of the servo electric cylinder. The distance sensor adopts the high-speed and high-precision LK-G402 focused light spot type laser displacement sensor of Keyence Company, which has a sampling frequency of up to 50KHz and a repeatability of 2μm, and can provide reliable real-time data for motion modeling. The camera used is KEYENCE CA-H2100MX, a 21-megapixel, 16x black-and-white camera. The main unit of the visual system uses KEYENCE XG-X products. Image processing uses VisonEditor software to ensure rapid detection and processing of images.

[0016] The present invention also discloses a bellows waveform testing method, which uses the above-mentioned device and comprises the following steps:

[0017] S1, install the specimen vertically on the rotating table,

[0018] S2. According to the through - diameter of the test piece, the servo cylinder adjusts the focal distance of the laser ranging. Input the measured length of the test piece. The vertical servo drives the measuring device to move to the top of the test piece. The servo starts to move slowly downward from the top, finds the minimum and maximum distances, which are the wave crest and wave trough, and marks them. The marking can be carried out manually or by automatic inkjet coding.

[0019] S3. When it runs to the bottom of the device, the marking ends. At the same time, the laser measurement data and the vertical servo data in the whole process are combined to generate an initial waveform curve.

[0020] S4. After other tests on the test piece, reinstall the test piece.

[0021] S5. The lifting motor runs, driving the servo cylinder to move downward from top to bottom. The marking position is identified by a high - speed camera and fed back to the ranging sensor. The data of the vertical movement of the servo cylinder and the horizontal extension data when the feedback signal is collected are acquired, compared with the previous measurement data, and the wave - distance change rate is calculated.

[0022] The principle and working process of the structure of the present invention are further described below.

[0023] The structure of the present invention mainly consists of a test - piece rotation mechanism and a sensor movement mechanism. The test - piece rotation mechanism consists of a main body bracket and a rotating disk. Among them, the servo motor is connected to the test - piece installation disk through a coupling structure, driving the disk to rotate, and can perform precise movement at a fixed speed and fixed angle within 360 degrees, meeting the needs of multi - angle and multiple measurements of the same test piece. The test - piece installation disk is designed with a cross - shaped installation groove, which can be used for the installation and testing of bellows of multiple sizes. The sensor movement mechanism is mainly used for the two - axis movement of the sensor. The vertical movement is used to measure waveform data, and the horizontal movement is used to adjust the distance between the sensor and the test piece to be tested. The horizontal movement uses an electric - cylinder structure to drive the sensor, ensuring the best working distance between the sensor and the workpiece while also ensuring that there is no interference between the mechanism and the test piece when the sensor retreats. The vertical movement uses a precision lead - screw slide structure. The slide drives the horizontal movement mechanism and then drives the sensor to complete the measurement of the waveform in the vertical direction. The movements of both axes are servo - driven, and precise movement at a fixed speed and fixed distance can be completed.

[0024] A waveform - curve database is established by collecting the measurement data of the laser displacement sensor and the movement - distance data of the servo in the vertical direction. Then, according to the comparison of the waveform data before and after the marking position by the high - speed camera, the wave - distance change rate under different conditions is calculated.

[0025] The core of the measurement lies in achieving relative motion in the vertical direction of the bellows by a high-precision laser displacement sensor at an appropriate measurement distance. The measurement data of the laser displacement sensor and the motion distance data of the servo in the vertical direction are collected into the upper computer in real time. Through the program designed by LabVIEW software, the corresponding curve, i.e., the waveform of the bellows, is generated, and the wave pitch data of the specimen is extracted and saved. The lower computer uses Schneider PLC as the platform, which has 40 digital input and output interfaces to complete the control of other sensors, air valves, alarm devices, etc., and has a CAN bus interface for communication with three servos in the vertical, horizontal directions of the rotating platform and the sensor to complete the high-speed control and monitoring of multiple servo motions.

[0026] During the test, the specimen is vertically installed on the rotating table. According to the nominal diameter of the specimen, the servo electric cylinder operates to adjust the focal distance of the laser ranging. According to the length of the specimen, the vertical servo drives the measuring device to move to the top of the specimen. The servo starts to move slowly downward from the top, finds the wave peaks and wave valleys, and the light spot of the laser ranging stops. Marking lines are made according to the light spot position. When it runs to the bottom of the equipment, the marking ends. At the same time, the laser measurement data and the vertical servo data in the whole process are combined to generate the initial waveform curve. After other tests and pressure tests are completed, the specimen is reinstalled, the measuring device runs at a low speed, and the high-speed camera moves from top to bottom. According to the number of marking lines, the measuring device is feedback to stop, and the data of the vertical movement is collected and compared with the previous measurement data to calculate the wave pitch change rate.

[0027] The structure of the present invention can effectively solve the cumbersome work of multiple manual clamping, measurement, and recording in the high-frequency waveform testing work of bellows by current bellows production enterprises and related testing institutions. The measurement and recording processes are all automatically completed by the equipment, which changes the influence of manual measurement by different people with different measuring tools on the measurement results and realizes the efficient, accurate, and stable measurement of the bellows waveform.

Claims

1. A method for testing the waveform of a corrugated pipe, characterized in that: It is tested by using a corrugated pipe waveform testing device; The corrugated pipe waveform testing device includes a base, on which a rotating mounting plate for mounting the test piece is provided. A bracket with a track is also provided on the base. An elevating motor with a lead screw is provided above the bracket. The lead screw cooperates with a servo cylinder sliding on the track. A high-speed camera is provided on the cylinder body of the servo cylinder, and a distance measuring sensor cooperating with the test piece is provided at the movable end of the servo cylinder; A marker is also provided at the movable end of the servo cylinder; The method for testing the waveform of the corrugated pipe includes the following steps: S1, Vertically mount the test piece on the rotating table, S2, According to the nominal diameter of the test piece, the servo cylinder adjusts the focal distance of the distance measuring sensor. According to the length of the test piece, the vertical servo drives the measuring device to move to the top of the test piece. The servo starts to move slowly downward from the top to find the minimum and maximum distances, which are the wave peaks and wave valleys, and mark them; S3, When it runs to the bottom of the device, the marking ends. At the same time, the laser measurement data and the vertical servo data during the whole process are combined to generate an initial waveform curve; S4, After the test piece is subjected to other tests, reinstall the test piece, S5, The elevating motor runs to drive the servo cylinder to move downward from top to bottom. The high-speed camera identifies the marking position and feeds it back to the distance measuring sensor to collect the data of the vertical operation of the servo cylinder when the feedback signal is generated, and compares it with the previous measurement data to calculate the wave distance change rate.

2. The corrugated pipe waveform testing method according to claim 1, wherein: The rotating mounting plate is rotatably connected to the base, and a rotating motor for driving the rotation of the rotating mounting plate is also provided on the base.

3. The corrugated pipe waveform testing method according to claim 1, wherein: The test piece to be tested is fixed on the rotating mounting plate through a flange.

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