A dual-mode plastic pipe creep ratio performance testing device

Abstract

The invention discloses a dual-mode plastic pipe creep ratio performance test device, including a frame, a driving device, a lifting device, a sample positioning device, a loading device, a protective device, an inner diameter measuring device and a control system, wherein the sample positioning device is installed on the bottom plate of the frame, the lifting devices are respectively installed on both sides of the frame, a middle cross beam is arranged on the lifting device, the driving device is arranged at the bottom of the frame and is transmission-connected with the lifting device, a loading device is installed on the middle cross beam, a pressing plate is arranged at the bottom of the loading device, one end of the pressing plate is installed on the middle cross beam through a connecting piece, an inner diameter measuring device is installed on the other end of the pressing plate, and the driving device drives the lifting device to operate and then drives the middle cross beam to move up and down to realize the loading of the sample. The invention has a mechanical and electrical dual-mode loading function, which can be loaded by mechanical weights or by electric control, and solves the problem of the instrument's dependence on the external environment and loading preload during the test.

Description

Technical Field

[0001] The invention relates to the technical field of physical property testing devices for plastic pipes, and in particular to a dual-mode plastic pipe creep ratio performance testing device. Background Art

[0002] Dual-mode plastic pipe creep ratio performance test equipment is mainly used to measure the creep of plastic pipe samples under specified conditions and to estimate long-term trends. Non-pressure buried plastic pipes for drainage and sewage treatment must withstand external pressure loads from the landfill cover above and around the pipes during use, which will cause them to deform to varying degrees. As time goes on, this deformation will gradually accumulate and increase, which is called creep.

[0003] This test is a long-term continuous test. The existing commercial products and technologies in China are all electrically controlled loading methods. During long-term tests, they are more dependent on the external environment, such as power supply. If a power outage occurs, the loading force value will fail and the test will be interrupted. This situation is particularly unfavorable for long-term tests. It is impossible to complete the complete long-term continuous test and obtain accurate test results. On the other hand, in order to achieve a constant loading force value, this loading method requires the control system to make real-time fine adjustments to the loading force value, so that the loading force value is always in a state of slight fluctuation, and the stability of the loading force value cannot be guaranteed. Summary of the invention

[0004] The purpose of the present invention is to provide a dual-mode plastic pipe creep ratio performance testing device to solve the problems of unstable loading force value, low precision and long-term test dependence on external environment.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The invention discloses a dual-mode plastic pipe creep ratio performance testing device, comprising a frame, a driving device, a lifting device, a sample positioning device, a loading device, a protective device, an inner diameter measuring device and a control system. The frame is a frame structure, the sample positioning device is installed on the bottom plate of the frame, the lifting devices are respectively installed on both sides of the frame, a middle cross beam is arranged on the lifting device, the driving device is arranged at the bottom of the frame and is transmission-connected with the lifting device, the loading device is installed on the middle cross beam, the protective device is arranged above the frame and corresponds to the loading device, a pressing plate is arranged at the bottom of the loading device, one end of the pressing plate is installed on the middle cross beam through a connecting piece, the inner diameter measuring device is installed on the other end of the pressing plate, the center of the pressing plate and the center of the sample positioning device are located on the same vertical plane, the driving device drives the lifting device to operate and then drives the middle cross beam to move up and down to realize the loading of the sample; the driving device, the loading device and the inner diameter measuring device are all electrically connected to the control system.

[0007] Furthermore, the sample positioning device includes a guide column, a pressure rod, two positioning blocks, a guide wheel, a displacement sensor and a sample support plate. The sample support plate is installed on the bottom plate of the frame, the positioning block is installed on the sample support plate, the spacing between the two positioning blocks is adapted to the length of the sample, the guide column is mounted with a pressure rod, the guide column is connected through the positioning block, the guide wheel and the displacement sensor are installed on the pressure rod, and the top end of the pull rope of the displacement sensor passes through the guide wheel and is connected to the inner diameter measuring device.

[0008] Furthermore, the inner diameter measuring device includes a tower pole, a tower pole seat, a hand twist, a suspension rod, a probe rod and a spring. The tower pole seat is installed on one side of the pressure plate, the tower pole is installed on the tower pole seat by the hand twist and the bottom is connected to one end of the suspension rod, the other end of the suspension rod is connected to the probe rod through a spring, the end of the pull rope of the displacement sensor is connected to the bottom end of the probe rod, and the displacement sensor is electrically connected to the control system.

[0009] Furthermore, the loading device includes a sliding sleeve, an optical axis and a force sensor. The sliding sleeve is installed on the middle cross beam. The optical axis is slidingly matched with the sliding sleeve. The bottom of the optical axis is connected to the pressure plate. A force sensor is installed between the optical axis and the pressure plate. The force sensor is electrically connected to the control system.

[0010] Furthermore, the loading device also includes weights, and the weights are stacked on the optical axis.

[0011] Furthermore, the protection device includes a protection rod connecting seat, a plurality of protection rods and a protection cover, the bottom of the protection rod is connected to the protection rod connecting seat, and the protection rod connecting seats are evenly distributed on the middle beam corresponding to the circumferential position of the weight.

[0012] Furthermore, the lifting device is a ball screw, and both ends of the middle cross beam are threadedly connected to the ball screw.

[0013] Furthermore, the driving device includes a motor, a reducer, a synchronous belt and a synchronous pulley. The motor is connected to the reducer and installed at the bottom of the frame. The synchronous pulley is installed at the bottom of the ball screw, and the synchronous pulley is driven by the synchronous belt; the output shaft of the reducer is connected to the driving pulley, and the driving pulley is connected to any synchronous pulley through the synchronous belt. The driving pulley drives the synchronous pulley to rotate and then drives the ball screws on both sides to rotate synchronously, and the motor is electrically connected to the control system.

[0014] Furthermore, the control system includes a central processing unit, a main control unit, an analog input module, a digital input module and a communication interface. The main control unit controls the driving device through the output interface and then controls the lifting of the beam. The main control unit is connected to and communicates with the computer through the communication interface; the analog input module collects force value signals and converts them into digital signals and transmits them to the central processing unit for processing; the digital input module collects digital signals generated by the encoder and transmits them to the central processing unit for processing.

[0015] Compared with the prior art, the beneficial technical effects of the present invention are:

[0016] The invention has a mechanical and electrical dual-mode loading function, and can be loaded by mechanical weights or by electric control, thereby solving the problems of the instrument's dependence on the external environment, test load (a load in which the sample is compressed and deformed to a certain proportion) and loading preload (samples of different specifications are loaded with different preloads) during the test, solving the technical problems of the creep ratio test method for thermoplastic plastic pipes, and meeting the standard requirements of GB / T18042-2000.

[0017] The mechanical weight loading method of the present invention provides a stable constant force for the test, ensuring that even when the instrument is powered off, the loading force value is not affected, the accuracy remains unchanged, and the test can still be carried out normally, thereby ensuring the reliability, continuity and stability of long-term tests.

[0018] The protection system of the present invention provides safety protection when adopting the mechanical weight loading mode test. A plurality of protection rods are distributed around the weight. The upper protection cover is used to protect the weight when the weight is in a high position to prevent the weight from falling off and tilting, which may cause safety hazards. Protection can also be provided around the weight in the form of a protection net, a protection cover, etc.

[0019] The electric control loading function of the present invention can realize functions such as long-term or short-term constant load, constant speed, and rate control, and can load the pipe steadily within a specified time, load preload and control loading, solve the problem of loading preload, and ensure that the loading force is stable and repeatable; at the same time, before loading the mechanical weight, the electric control loading mode can be used to pre-check that the tested pipe reaches the force value required for the standard test, ensuring that the weight loading test is successful once, avoiding repeated disassembly and installation of the weight, improving the test efficiency, and reducing the test labor intensity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below in conjunction with the accompanying drawings.

[0021] Figure 1 It is a front view of the dual-mode plastic pipe creep ratio performance testing device of the present invention;

[0022] Figure 2 It is a side view of the dual-mode plastic pipe creep ratio performance testing device of the present invention;

[0023] Figure 3 It is a schematic structural diagram of a sample positioning device and an inner diameter measuring device of the present invention;

[0024] Explanation of the reference numerals in the accompanying drawings: 1. frame; 101. middle cross beam; 2. driving device; 201. motor; 202. reducer; 203. synchronous belt; 204. synchronous pulley; 3. lifting device; 4. sample positioning device; 401. guide column; 402. pressure rod; 403. positioning block; 404. guide wheel; 405. displacement sensor; 5. loading device; 501. pressure plate; 502. sliding sleeve; 503. optical axis; 504. force sensor; 505. weight; 6. protective device; 601. protective rod; 602. protective rod connecting seat; 603. protective cover; 7. inner diameter measuring device; 701. tower pole; 702. tower pole seat; 703. hand twist; 704. suspension rod; 705. probe rod; 706. spring; 8. control system. DETAILED DESCRIPTION

[0025] like Figure 1 - Figure 3As shown, a dual-mode plastic pipe creep ratio performance testing device includes a frame 1, a driving device 2, a lifting device 3, a sample positioning device 4, a loading device 5, a protective device 6, an inner diameter measuring device 7 and a control system 8. The frame 1 is a frame structure, the sample positioning device 4 is installed on the bottom plate of the frame 1, the lifting devices 3 are respectively installed on both sides of the frame 1, a middle cross beam 101 is arranged on the lifting device 3, the driving device 2 is arranged at the bottom of the frame 1 and is transmission-connected with the lifting device 3, the loading device 5 is installed on the middle cross beam 101, the protective device 6 is installed on the inner diameter measuring device 7 and the control system 8. The device 6 is arranged above the frame 1 and corresponds to the loading device 5. A pressing plate 501 is arranged at the bottom of the loading device 5. One end of the pressing plate 501 is installed on the middle beam 101 through a connecting piece. An inner diameter measuring device 7 is installed on the other end of the pressing plate 501. The center of the pressing plate 501 and the center of the sample positioning device 4 are located on the same vertical plane. The driving device 2 drives the lifting device 3 to operate and then drives the middle beam 101 to move up and down to realize the loading of the sample; the driving device 2, the loading device 5, and the inner diameter measuring device 7 are all electrically connected to the control system 8.

[0026] In this embodiment, a pipe of a specified length is cut, placed on a sample support plate 406, and positioned by the sample positioning device 4, the middle crossbeam 101 is moved by the lifting device 3, the inner diameter measuring device 7 is installed in the sample, and the control system 8 controls the driving device 2 to continue to move the middle crossbeam 101 downward, so that the loading device 5 applies a fixed vertical pressure to the pipe and continues to apply pressure for 1008h (42 days), and the deformation of the inner diameter of the pipe sample is detected by the inner diameter measuring device 7. The deformation of the pipe is recorded at a specified time, and then a curve and equation of the relationship between the pipe deformation and time are established, and the linear relationship of the data is analyzed, and finally the creep ratio of the pipe is obtained by calculating the deformation extrapolated for two years.

[0027] Specifically, the sample positioning device 4 includes a guide column 401, a pressure rod 402, two positioning blocks 403, a guide wheel 404, a displacement sensor 405 and a sample support plate 406. The sample support plate 406 is installed on the bottom plate of the frame 1, and the positioning block 403 is installed on the sample support plate 406. The spacing between the two positioning blocks 403 is adapted to the length of the sample. The guide column 401 is mounted with a pressure rod 402, and the guide column 401 is connected through the positioning block 403. The guide wheel 404 and the displacement sensor 405 are installed on the pressure rod 402. The top end of the pull rope of the displacement sensor 405 passes through the guide wheel 404 and is connected to the inner diameter measuring device 7.

[0028] In this embodiment, the sample is placed between two positioning blocks 403, and the position of the middle cross beam 101 is adjusted so that the lower plane of the pressure plate 501 is 1-2 mm away from the outer diameter of the sample. Then, a pressure rod 402 assembly consisting of a pressure rod 402, a guide wheel 404, and a displacement sensor 405 is installed in the sample. The pressure rod 402 assembly should be installed in the center of the inner diameter of the sample and fit against the lower wall of the inner diameter of the sample.

[0029] Specifically, the inner diameter measuring device 7 includes a tower 701, a tower seat 702, a hand twist 703, a suspension rod 704, a probe rod 705 and a spring 706. The tower seat 702 is installed on one side of the pressure plate 501. The tower 701 is installed on the tower seat 702 through the hand twist 703 and the bottom is connected to one end of the suspension rod 704. The other end of the suspension rod 704 is connected to the probe rod 705 through the spring 706. The end of the pull rope of the displacement sensor 405 is connected to the bottom end of the probe rod 705, and the displacement sensor 405 is electrically connected to the control system 8.

[0030] After the sample is placed in this embodiment, the lower plane of the pressure plate 501 is 1-2mm away from the outer diameter of the sample. At this time, the position of the tower rod 701 is adjusted, and the spring 706 is compressed to make the probe rod 705 contact the inner wall of the sample. The pull rope of the displacement sensor 405 is connected to the probe rod 705 through the guide wheel 404, and then the lifting device 3 is driven to ensure that when the pressure plate 501 contacts the sample, the probe rod 705 keeps in contact with the inner wall of the sample. The pressure rod 402 assembly fits with the lower wall of the inner diameter of the sample through its own weight, and the probe rod 705 adapts to the upper wall of the inner diameter of the sample through the tension of the spring 706 to achieve a fitting state, and the displacement sensor 405 detects the change value of the inner diameter of the sample in real time.

[0031] Specifically, the loading device 5 includes a sleeve 502, an optical axis 503 and a force sensor 504. The sleeve 502 is installed on the middle beam 101. The optical axis 503 and the sleeve 502 are slidably matched. The bottom of the optical axis 503 is connected to the pressure plate 501. The force sensor 504 is installed between the optical axis 503 and the pressure plate 501. The middle beam 101 is controlled to move up and down by the driving device 2 to realize the loading of the sample; the force sensor 504 is electrically connected to the control system 8.

[0032] This embodiment uses an electric control method to load the required force value and measure the change in the inner diameter of the sample. When the electric loading mode is used for the test, the optical axis 503 is fixed and does not slide in the sliding sleeve 502. At this time, the pressing plate 501, the force sensor 504, the sliding optical axis 503 and the middle cross beam 101 form a rigid component, and the movement of the middle cross beam 101 is controlled by the driving system to achieve loading on the sample.

[0033] In addition, before loading the mechanical weight 505, the electric control loading mode can be used to search for the required loading force value. This function can calculate the force value required according to the standard requirements. Based on this, the weight 505 loading test is successful at one time, avoiding repeated disassembly and assembly of the weight 505, improving the test efficiency and reducing the test labor intensity.

[0034] Specifically, the loading device 5 further includes a weight 505 , and the weight 505 is stacked on the optical axis 503 .

[0035] This embodiment directly loads through a mechanical weight 505 , which is connected through an optical axis 503 in the sleeve 502 . The optical axis 503 also serves as a part of the weight 505 . The optical axis 503 directly transmits the loading force to the sample through a force sensor 504 .

[0036] The driving device 2 drives the middle cross beam 101 to move upward, and the pressing plate 501, the force sensor 504, the sliding optical axis 503, and the weight 505 move upward together with the middle cross beam 101. When the distance between the lower plane of the pressing plate 501 and the upper plane of the sample support plate 406 is greater than the outer diameter of the sample tube, the middle cross beam 101 can stop moving. Place the sample in the center of the sample support plate 406. Adjust the position of the middle cross beam 101 so that the distance between the lower plane of the pressing plate 501 and the outer diameter of the sample is 1-2mm. Install the inner diameter measuring device 7 in the sample. Move the middle cross beam 101 downward so that the force value of the weight 505 acts on the force sensor 504 through the optical axis 503. The force sensor 504 acts the gravity of the weight 505 on the sample through the pressing plate 501, realizing the loading of the mechanical weight 505.

[0037] Specifically, the protection device 6 includes a protection rod connecting seat 602, a plurality of protection rods 601 and a protection cover 603. The bottom of the protection rod 601 is connected to the protection rod connecting seat 602, and the protection rod connecting seat 602 is evenly distributed on the middle beam 101 corresponding to the circumferential position of the weight 505.

[0038] The protective cover 603 of this embodiment is used to protect the weight 505 when the weight 505 is at a high position, so as to prevent the weight 505 from falling off and tilting, which may cause safety hazards. There can be one protective rod 601, or N protective rods (N≥1); each protective rod 601 can be a single one, or divided into M (M≥1) sections. A protective cover 603 can be used around the weight 505, or a protective net, a grille, or a distributed protective rod 601 structure can be used.

[0039] Specifically, the lifting device 3 is a ball screw, and both ends of the middle cross beam 101 are threadedly connected to the ball screw. The driving device 2 includes a motor 201, a reducer 202, a synchronous belt 203 and a synchronous pulley 204. The motor 201 is connected to the reducer 202 and installed at the bottom of the frame 1. The bottom of the ball screw is installed with a synchronous pulley 204, and the synchronous pulley 204 is driven by the synchronous belt 203; the output shaft of the reducer 202 is connected to the driving pulley, and the driving pulley is connected to any synchronous pulley 204 through the synchronous belt 203. The driving pulley drives the synchronous pulley 204 to rotate and then drives the ball screws on both sides to rotate synchronously. The motor 201 is electrically connected to the control system 8.

[0040] Specifically, the control system 8 includes a central processing unit, a main control unit, an analog input module, a digital input module and a communication interface. The main control unit controls the drive device 2 through the output interface to control the lifting of the beam. The main control unit is connected to the computer through the communication interface and communicates; the analog input module collects the force value signal and converts it into a digital signal and transmits it to the central processing unit for processing; the digital input module collects the digital signal generated by the encoder and transmits it to the central processing unit for processing

[0041] The working process of the present invention is as follows:

[0042] Cut a pipe sample of a specified length and place it between the pressing plate 501 and the sample support plate 406. Install the inner diameter measuring device 7 in the sample and load the preload Fo for deformation zero point positioning. Fo is a minimum of 7.5N and a maximum uncertain force calculated based on the pipe diameter. When the inner diameter of the pipe is di=0.1m, Fo=7.5N, and when di>0.1m, Fo=75diN. Adjust the inner diameter test assembly to zero after the specified time. Start to formally load a constant test load F. The applied F value should make the deformation of the pipe reach 1.5% of its inner diameter at 6min. This deformation is taken as the initial deformation and recorded as y. Then continue to measure and record the deformation values ​​at the specified time points. Each test should have at least multiple sets of time-deformation data. The functional relationship between deformation and time is similar to a linear exponential function. The semi-logarithmic curve of time-deformation on the semi-logarithmic coordinate graph is a straight line. Therefore, the linear equation Y,-B+Migt can be established to make a linear regression for all data, and the least squares method can be used to obtain constants B, M and correlation coefficient R and analyze them. The creep ratio of the pipe can be obtained by calculating the deformation after extrapolating two years.

[0043] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A dual-mode plastic pipe creep ratio performance testing device, characterized by: The invention comprises a frame (1), a driving device (2), a lifting device (3), a sample positioning device (4), a loading device (5), a protective device (6), an inner diameter measuring device (7) and a control system (8); the frame (1) is a frame structure; the sample positioning device (4) is mounted on the bottom plate of the frame (1); the lifting devices (3) are respectively mounted on both sides of the frame (1); a middle cross beam (101) is arranged on the lifting device (3); the driving device (2) is arranged at the bottom of the frame (1) and is transmission-connected to the lifting device (3); the loading device (5) is mounted on the middle cross beam (101); the protective device (6) is arranged on the frame (1) above and corresponding to the loading device (5), a pressing plate (501) is arranged at the bottom of the loading device (5), one end of the pressing plate (501) is mounted on the middle cross beam (101) through a connecting piece, the other end of the pressing plate (501) is mounted on the inner diameter measuring device (7), the center of the pressing plate (501) and the center of the sample positioning device (4) are located on the same vertical plane, the driving device (2) drives the lifting device (3) to operate and thereby drives the middle cross beam (101) to move up and down, thereby realizing the loading of the sample; the driving device (2), the loading device (5) and the inner diameter measuring device (7) are all electrically connected to the control system (8); The sample positioning device (4) comprises a guide column (401), a pressure rod (402), two positioning blocks (403), a guide wheel (404), a displacement sensor (405) and a sample support plate (406), wherein the sample support plate (406) is mounted on the bottom plate of the frame (1), the positioning block (403) is mounted on the sample support plate (406), the spacing between the two positioning blocks (403) is adapted to the length of the sample, the guide column (401) is provided with a pressure rod (402), the guide column (401) is connected through the positioning block (403), the guide wheel (404) and the displacement sensor (405) are mounted on the pressure rod (402), and the top end of the pull rope of the displacement sensor (405) passes through the guide wheel (404) and is connected to the inner diameter measuring device (7); The inner diameter measuring device (7) comprises a tower (701), a tower seat (702), a hand twist (703), a suspension rod (704), a probe rod (705) and a spring (706); the tower seat (702) is mounted on one side of the pressure plate (501); the tower (701) is mounted on the tower seat (702) by means of the hand twist (703) and the bottom of the tower (701) is connected to one end of the suspension rod (704); the other end of the suspension rod (704) is connected to the probe rod (705) by means of a spring (706); the end of the pull rope of the displacement sensor (405) is connected to the bottom end of the probe rod (705); and the displacement sensor (405) is electrically connected to the control system (8); The loading device (5) comprises a sliding sleeve (502), an optical axis (503) and a force sensor (504); the sliding sleeve (502) is mounted on the middle cross beam (101); the optical axis (503) and the sliding sleeve (502) are slidably matched; the bottom of the optical axis (503) is connected to the pressing plate (501); a force sensor (504) is installed between the optical axis (503) and the pressing plate (501); and the force sensor (504) is electrically connected to the control system (8).

2. The dual-mode plastic pipe creep ratio performance testing equipment according to claim 1, characterized in that: The loading device (5) further comprises a weight (505), wherein the weight (505) is stacked on the optical axis (503).

3. The dual-mode plastic pipe creep ratio performance testing equipment according to claim 2, characterized in that: The protection device (6) comprises a protection rod connecting seat (602), a plurality of protection rods (601) and a protection cover (603); the bottom of the protection rod (601) is connected to the protection rod connecting seat (602); and the protection rod connecting seat (602) is evenly distributed on the middle cross beam (101) corresponding to the circumferential position of the weight (505).

4. The dual-mode plastic pipe creep ratio performance testing device according to claim 1, characterized in that: The lifting device (3) is a ball screw, and both ends of the middle cross beam (101) are threadedly connected to the ball screw.

5. The dual-mode plastic pipe creep ratio performance testing device according to claim 4, characterized in that: The driving device (2) comprises a motor (201), a reducer (202), a synchronous belt (203) and a synchronous pulley (204); the motor (201) is connected to the reducer (202) and is installed at the bottom of the frame (1); the synchronous pulley (204) is installed at the bottom of the ball screw, and the synchronous pulley (204) is driven by the synchronous belt (203); the output shaft of the reducer (202) is connected to the driving pulley, and the driving pulley is connected to any synchronous pulley (204) through the synchronous belt (203); the driving pulley drives the synchronous pulley (204) to rotate and then drives the ball screws on both sides to rotate synchronously; the motor (201) is electrically connected to the control system (8).

6. The dual-mode plastic pipe creep ratio performance testing device according to claim 1, characterized in that: The control system (8) includes a central processing unit, a main control unit, an analog input module, a digital input module and a communication interface. The main control unit controls the drive device (2) through the output interface and then controls the lifting of the beam. The main control unit is connected to and communicates with the computer through the communication interface; the analog input module collects force value signals and converts them into digital signals and transmits them to the central processing unit for processing; the digital input module collects digital signals generated by the encoder and transmits them to the central processing unit for processing.

Images