Two-degree-of-freedom swing table for ultrahigh test piece

Abstract

The invention provides a two-degree-of-freedom swing table for an ultrahigh test piece, and belongs to the technical field of offshore ultrahigh test piece testing. Comprising a base structure, the upper surface of which is provided with a fixed hinge and a platform for installing a tested piece; the four concrete stand columns are arranged on the foundation and connected into a whole through the steel handrails, and embedded parts are arranged on the stand columns; the rolling and pitching driving device comprises a rolling actuator and a pitching actuator, the tail of the rolling and pitching driving device is fixed to an embedded part of the stand column through a rear hinge, and the head of the rolling and pitching driving device is fixed to the connecting tool through a front hinge. And the connecting tool is fixedly connected with the tested piece. The swing table can accurately simulate the ocean sloshing working condition, and an effective testing means is provided for verifying the performance of the LNG / FLNG wound tube type heat exchanger under the static and sloshing conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the offshore super-high test piece testing technical field, and in particular to a super-high test piece two-degree-of-freedom swing table. BACKGROUND

[0002] In order to realize the application of the pipe-coil heat exchanger on the offshore LNG-FPSO, a large two-degree-of-freedom swing table capable of simulating the ocean sloshing working condition is needed to be built to complete the performance test of the LNG / FLNG pipe-coil heat exchanger engineering machine under the static and sloshing conditions, so as to verify the key technology of the self-developed large LNG / FLNG pipe-coil heat exchanger of CNOOC. The swing table makes the pipe-coil heat exchanger and its supporting frame realize the single-degree-of-freedom motion and the two-degree-of-freedom compound motion under the premise of ensuring safety and reliability.

[0003] (1) Pipe-coil heat exchanger machine parameters: The pipe-coil heat exchanger is in the form of a skid, the frame is a steel structure, and the main frame size is about 4m (long) x 4m (wide) x 38m (high); (2) The operating weight of the pipe-coil heat exchanger (including liquid) and its supporting frame is not greater than 160t.

[0004] The two-degree-of-freedom swing table is usually composed of a platform (for installing the test piece) and two or four actuators (for driving the platform to swing), as shown in Figure 1 . This swing table is not suitable for super-high test pieces such as pipe-coil heat exchangers, because the mass center of the test piece is too high, the moment of inertia is too large, and the driving torque required for swinging is too large, which is difficult to manufacture. SUMMARY

[0005] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art, and to provide a super-high test piece two-degree-of-freedom swing table, comprising: a foundation structure, the upper surface of which is provided with a fixed hinge and a platform for installing the test piece; four concrete columns, which are arranged on the foundation and connected into a whole through a steel railing, and are provided with embedded parts on the columns; a pitch and roll driving device, which includes a pitch actuator and a roll actuator, the tail of which is fixed on the embedded parts of the columns through a rear hinge, and the head of which is fixed on the connecting tooling through a front hinge; a connecting tooling, which is fixedly connected with the test piece; a hydraulic system, comprising: a single-outlet asymmetric hydraulic cylinder, the rod cavity of which is controlled through an explosion-proof servo valve; an explosion-proof servo valve and a cover plate type cartridge valve are arranged between the explosion-proof servo valve and the hydraulic cylinder; an electromagnetic reversing valve controls the opening and closing of the cartridge valve; Electromagnetic reversing valve two and hydraulic control check valve are used to restore to working zero position during swing table maintenance; Pressure sensor monitors the pressure of rod cavity of hydraulic cylinder.

[0006] Preferably, the hydraulic system is connected in the following way: the rod cavity of the hydraulic cylinder is connected to the load oil port B of the explosion-proof servo valve, and the rodless cavity is connected to the oil return pipeline; a cover plate type cartridge valve is connected in parallel to the oil circuit between the explosion-proof servo valve and the hydraulic cylinder; electromagnetic reversing valve one is connected to the control cavity of the cartridge valve through a control oil circuit; the hydraulic control check valve is arranged between the rod cavity of the hydraulic cylinder and the oil supply / return pipeline; and the pressure sensor is connected to the oil circuit of the rod cavity of the hydraulic cylinder.

[0007] Preferably, the hydraulic system further comprises: electromagnetic reversing valve three and a throttle valve arranged on the explosion-proof servo valve mounting block; electromagnetic reversing valve three is used to connect the oil supply pipeline and the oil return pipeline; and the throttle valve is used to adjust the circulation flow rate, and together functions as pipeline flushing and hydraulic oil preheating.

[0008] Preferably, the structural parameters of the swing table include: The radius Ra of the front connecting hinge point is 2750 mm; The radius Rb of the rear connecting hinge point is 7600 mm; The distance L2 between the front and rear connecting hinge points in the working middle position is 4850 mm; The height H1 of the front connecting hinge point in the middle position is 12700 mm; The height H2 of the rear connecting hinge point in the middle position is 12700 mm.

[0009] Preferably, the parameters of the hydraulic cylinder include: The diameter of the piston / piston rod is 200 / 125 mm; The effective stroke is 2247 mm; The maximum extension / retraction speed is 0.697 m / s.

[0010] Further preferably, the rated flow rate of the explosion-proof servo valve is 630 L / min, and the valve pressure drop is 7 MPa.

[0011] Further preferably, the actuator only generates pulling force and does not generate pushing force.

[0012] Preferably, the swing table is used for testing around-pipe heat exchangers, and the size of the main frame of the test piece is 4 m (length) x 4 m (width) x 38 m (height).

[0013] Preferably, the swing table realizes single-degree-of-freedom motion and two-degree-of-freedom compound motion of the test piece by controlling the displacement of the four actuators.

[0014] Further preferably, the hydraulic system can make the plug-in valve close and stop the swing table movement by the electromagnetic reversing valve one power failure when the control system fails; the electromagnetic reversing valve two can be used to make the platform return to the working zero position after the swing table fails to stop, and the fault can be repaired.

[0015] Compared with the prior art, the present application has the following technical effects: Firstly, the swing table innovatively adopts a four-column support structure, which effectively solves the technical problem that the traditional swing table is difficult to drive super-high and large-mass test pieces by fixing the actuator tail on the column embedded part and connecting the head to the test piece. The unique hydraulic system design, including single-out-rod asymmetric hydraulic cylinder, explosion-proof servo valve control, plug-in valve safety protection and other devices, not only avoids the problem of actuator pressure rod instability, but also realizes precise motion control and fault safety protection function. This structure design enables the swing table to stably drive a 38-meter-high and 160-ton-tongue tube heat exchanger to perform two-degree-of-freedom compound motion, providing a reliable test platform for simulating the sea working condition of large LNG equipment.

[0016] Secondly, the swing table solves the problem of poor flowability of hydraulic oil in low-temperature environments by optimizing the design of the hydraulic oil circulation heating system, ensuring the reliable operation of the system in harsh environments. The innovative hydraulic circuit design, including the combination of electromagnetic reversing valves and throttling valves, realizes the rapid preheating of hydraulic oil, greatly improving the starting performance and working stability of the system in low-temperature environments. These technical measures collectively ensure that the swing table can accurately simulate ocean sloshing conditions, providing an effective test means for verifying the performance of LNG / FLNG tube heat exchangers under static and sloshing conditions. BRIEF DESCRIPTION OF DRAWINGS

[0017] For ease of illustration, the present application is described in detail by the following specific embodiments and drawings.

[0018] Figure 1 The figure is a common structure form of a two-degree-of-freedom swing table. Figure 2 The figure is a structure form of a two-degree-of-freedom swing table for super-high test pieces. Figure 3 The figure is a structure parameter diagram of a two-degree-of-freedom swing table for super-high test pieces. Figure 4 The figure is a hydraulic principle diagram of the actuator.

[0019] In the figure: 1, single-out-rod asymmetric hydraulic cylinder; 2, explosion-proof servo valve; 3, electromagnetic reversing valve one; 4.1, check valve one; 4.2, check valve two; 5, hydraulic control check valve; 6, electromagnetic reversing valve two; 7, cover plate type cartridge valve; 8, base structure; 9, electromagnetic reversing valve three; 10, throttle valve; 11, pressure sensor; 12, platform; 13, column; 14, railing; 15, roll and pitch driving device; 16, test piece; 17, connecting tool. DETAILED DESCRIPTION

[0020] The following is a specific embodiment of the present application and is combined with the accompanying drawings Figures 1-4 The technical solutions of the present application are further described, but the present application is not limited to these embodiments; in the following description, specific details such as specific configurations are provided only to help understand the embodiments of the present application. Therefore, it should be clear to those skilled in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present application.

[0021] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0022] As Figure 2 shown, a two-degree-of-freedom roll and pitch test bench for super-high test pieces comprises: a base structure 8, the upper surface of which is provided with a fixed hinge and a platform 12 for mounting a test piece; four concrete columns 13, which are arranged on the base structure 8 and connected into a whole through a steel railing 14, and are provided with embedded parts; a roll and pitch driving device 15, which comprises a roll actuator and a pitch actuator, the tail of which is fixed on the embedded parts of the columns through a rear hinge, and the head of which is fixed on a connecting tool 17 through a front hinge; the connecting tool 17 is fixedly connected with the test piece 16; a hydraulic system, which comprises: a single-out-rod asymmetric hydraulic cylinder, the rod cavity of which is controlled through an explosion-proof servo valve; a cover plate type cartridge valve is arranged between the explosion-proof servo valve and the hydraulic cylinder; an electromagnetic reversing valve one is used to control the opening and closing of the cartridge valve; an electromagnetic reversing valve two and a hydraulic control check valve are used to restore to the working zero position when the test bench is overhauled; an electromagnetic reversing valve three and a throttle valve; the electromagnetic reversing valve three is used to connect the oil supply pipeline and the oil return pipeline, and the throttle valve is used to adjust the circulating flow, and is used for pipeline flushing and hydraulic oil preheating.

[0023] a pressure sensor is used to monitor the pressure of the rod cavity of the hydraulic cylinder.

[0024] The structural parameters of the test bench comprise: The radius Ra of the front connecting hinge point is 2750mm; The radius Rb of the rear connecting hinge point circle is 7600 mm; When the machine is in the working position, the distance L2 between the front and rear connecting hinge points is 4850mm; When in the middle position, the height H1 of the front connecting hinge point is 12700mm; When in the middle position, the height H2 of the rear connecting hinge point is 12700mm.

[0025] Preferably, the parameters of the hydraulic cylinder include: The piston / piston rod diameter is 200 / 125mm; The effective stroke is 2247mm; The maximum extension / retraction speed is 0.697 m / s.

[0026] The rated flow rate of the explosion-proof servo valve is 630 L / min, and the valve pressure drop is 7 MPa.

[0027] The actuator generates only tension and not thrust.

[0028] The swing table is used to test a coiled tube heat exchanger. The main frame dimensions of the test specimen are 4m (length) × 4m (width) × 38m (height). The swing table achieves single-degree-of-freedom motion and two-degree-of-freedom combined motion of the test specimen by controlling the displacement of four actuators. In the event of a control system failure, the hydraulic system can stop the swing table by de-energizing the first solenoid directional valve to close the cartridge valve. After the swing table stops due to a failure, the second solenoid directional valve can be used to return the platform to the zero working position for troubleshooting.

[0029] right Figure 2 The structural parameters of the two-degree-of-freedom swing table shown are optimized. A schematic diagram of the structural parameters is shown below. Figure 3 As shown, the following four parameters determine the connection: the radius of the front hinge circle Ra, the radius of the rear hinge circle Rb, the height of the front hinge point H1, and the height of the rear hinge point H2.

[0030] The above four structural parameters determine the kinematic and dynamic characteristics of the rocker platform. When designing the rocker platform, these four structural parameters must first be determined according to the principles of optimal design. The distance L2 between the front and rear connecting hinge points when the rocker platform is in its zero-position working state is also considered.

[0031] The optimization of the swing table structure mainly involves determining the optimal structural parameters based on kinematic and dynamic analysis and calculations. The following principles are considered in the structural optimization design of the swing table: 1) No unusual structural design When singular configuration occurs, the mechanism becomes uncontrollable, and the force beyond the limit is generated at the connecting hinge, the swing table loses stability and even overturns. In the overall structure design, a structure without singular configuration is designed to fundamentally ensure the safety of the platform.

[0032] 2) Non-interference structure design Interference refers to the collision between components during the movement of the platform. In the overall structure design, it is necessary to ensure that there is no interference between components under various limit configurations.

[0033] 3) High inherent frequency of structure The frequency of the first mode of the structure is the main factor limiting the frequency characteristics of the system. Due to the large difference in the dynamic characteristics of each degree of freedom of the platform, the frequency of the structure vibration needs to be analyzed to ensure that the designed system structure meets the requirements of the system frequency characteristics.

[0034] 4) Small power and low operating cost In the design of the swing table structure, in addition to ensuring safety and performance, it is also necessary to reduce the power consumption of the system as much as possible and reduce the operating cost.

[0035] Due to the large stroke of the actuator and the long distance between the front and rear hinges, the actuator has a compression rod instability problem. In order to solve the compression rod instability problem of the actuator, the designed actuator only generates tension and does not generate thrust, and the tension of the four actuators drives the test piece to roll and pitch. The hydraulic principle of the actuator is shown in Figure 4 The principle is introduced as follows: Single rod asymmetric hydraulic cylinder 1, rod cavity connects load port B of explosion-proof servo valve 2 (another load port A is blocked), rodless cavity returns oil, hydraulic cylinder does not generate thrust, avoiding compression rod instability.

[0036] A cover plate type cartridge valve 7 is provided between the explosion-proof servo valve 2 and the hydraulic cylinder. When the electromagnetic reversing valve one 3 is powered on, the cover plate type cartridge valve 7 controls the cavity pressure relief, the cartridge valve is opened, and the explosion-proof servo valve controls the movement of the hydraulic cylinder. When the electromagnetic reversing valve one 3 is powered off, the highest pressure of the hydraulic cylinder rodless cavity or the hydraulic source is introduced into the control cavity of the cover plate type cartridge valve 7 through the one-way valve one 4.1 and the one-way valve two 4.2, so that the cartridge valve is closed, the explosion-proof servo valve loses control of the hydraulic cylinder, and the hydraulic cylinder stops at the current position. The swing table stops moving, which plays a safety protection role for the swing table.

[0037] When the control system fails and the swing table stops moving, the swing table needs to be repaired, at this time, the swing table needs to be restored to the working zero position (the platform is horizontal and the test piece is vertical), which can be realized through electromagnetic reversing valve two 6 and hydraulic control check valve 5. Taking roll as an example, the left electromagnet of electromagnetic reversing valve two 6 of No. 1 actuator is powered on, the oil supply of the hydraulic source enters the rod cavity of the hydraulic cylinder through the hydraulic control check valve 5, and No. 1 actuator retracts, at the same time, the right electromagnet of electromagnetic reversing valve two 6 of No. 2 actuator is powered on, the hydraulic control check valve 5 is opened in reverse, the rod cavity of the hydraulic cylinder is communicated with the oil return, and No. 2 actuator is pulled out, the swing table rolls, and according to the tilt direction of the swing table when it stops, the left or right electromagnet of the electromagnetic reversing valve two 6 of the roll actuator is powered on. When the swing table works normally, the left and right electromagnets of the electromagnetic reversing valve two 6 are both powered off, the hydraulic control check valve 5 makes the rod cavity of the hydraulic cylinder not communicated with the oil supply and the oil return, and the explosion-proof servo valve controls the normal movement of the hydraulic cylinder. The electromagnetic reversing valve two 6 and the hydraulic control check valve 5 are provided with a damping hole to limit the movement speed of the swing table during the recovery process.

[0038] The swing table is installed outdoors, and in winter, before the test, the hydraulic oil in the pipeline has large viscosity and poor flowability due to low temperature, which affects the performance of the explosion-proof servo valve. In order to solve this problem, electromagnetic reversing valve three 9 and throttle valve 10 are designed on the explosion-proof servo valve mounting block. Before the test, the hydraulic source is started (in the room), and the electromagnetic reversing valve three 9 is powered on, the oil supply pipeline and the oil return pipeline are connected, the hydraulic oil circulates, the opening degree of the throttle valve 10 is adjusted, the output pressure of the oil source is slightly lower than the rated pressure of the oil source, at this time, the hydraulic source outputs full flow (the constant pressure variable pump outputs full flow when the load pressure is lower than the constant pressure point), and the product of the circulating flow and the pressure is the output power of the hydraulic source, which is all used for heating the hydraulic oil. After the temperature of the hydraulic oil rises to the normal temperature, the test is started.

[0039] The pressure sensor 11 monitors the pressure of the rod cavity of the hydraulic cylinder, which can be used for setting overpressure protection.

[0040] Those skilled in the art to which the present application pertains can make various modifications or supplements to the described specific embodiments or adopt similar ways to replace them, but will not deviate from the inventive concept of the present application or exceed the scope defined by the appended claims.

Claims

1. A two-degree-of-freedom rocking table for ultra-high test specimens, characterized by, The utility model relates to a single-freedom and two-freedom compound motion test rig for a pipe heat exchanger, which comprises: a foundation structure with a fixed hinge and a platform for mounting a test piece on the upper surface thereof; four concrete columns arranged on the foundation and connected into a whole through a steel railing, the columns being provided with embedded parts; a roll-pitch driving device comprising a roll actuator and a pitch actuator, the tail of the driving device being fixed to the embedded parts of the columns through a rear hinge, and the head of the driving device being fixed to a connecting tool through a front hinge; a connecting tool fixedly connected to the test piece; a hydraulic system comprising: a single-outlet asymmetric hydraulic cylinder, the rod cavity of which is controlled by an explosion-proof servo valve; a cover-type cartridge valve provided between the explosion-proof servo valve and the hydraulic cylinder; an electromagnetic reversing valve I for controlling the opening and closing of the cartridge valve; an electromagnetic reversing valve II and a hydraulic control check valve for restoring the test rig to a working zero position during maintenance; a pressure sensor for monitoring the pressure of the rod cavity of the hydraulic cylinder.

2. The two-degree-of-freedom rocking table for super-high test specimens according to claim 1, characterized by, The hydraulic system is connected in the following manner: the rod cavity of the hydraulic cylinder is connected to the load oil port B of the explosion-proof servo valve, and the rodless cavity is connected to a return oil pipeline; a cover-type cartridge valve is provided in parallel in the oil circuit between the explosion-proof servo valve and the hydraulic cylinder; the electromagnetic reversing valve I is connected to the control cavity of the cartridge valve through a control oil circuit; the hydraulic control check valve is arranged between the rod cavity of the hydraulic cylinder and the oil supply / return pipeline; and the pressure sensor is connected to the oil circuit of the rod cavity of the hydraulic cylinder.

3. The two-degree-of-freedom rocking table for super-high test specimens according to claim 1, characterized by, The hydraulic system further comprises: an electromagnetic reversing valve III and a throttle valve provided on the mounting block of the explosion-proof servo valve; the electromagnetic reversing valve III is used to connect the oil supply pipeline and the return oil pipeline, and the throttle valve is used to adjust the circulation flow rate and for pipeline flushing and hydraulic oil preheating.

4. The two-degree-of-freedom rocking table for super-high test specimens according to claim 1, characterized by, The structural parameters of the test rig include: the front connecting hinge point circle radius Ra is 2750 mm; the rear connecting hinge point circle radius Rb is 7600 mm; the distance L2 between the front and rear connecting hinge points in the working middle position is 4850 mm; the front connecting hinge point height H1 in the middle position is 12700 mm; the rear connecting hinge point height H2 in the middle position is 12700 mm.

5. The two-degree-of-freedom rocking table for super-high test specimens according to claim 1, characterized by, The parameters of the hydraulic cylinder include: the piston / piston rod diameter is 200 / 125 mm; the effective stroke is 2247 mm; the maximum extension / retraction speed is 0.697 m / s.

6. The two-degree-of-freedom rocking table for super-high test specimens according to claim 1, characterized by, The rated flow rate of the explosion-proof servo valve is 630 L / min, and the valve pressure drop is 7 MPa.

7. The two-degree-of-freedom rocking table for super-high test specimens according to claim 1, characterized by, The actuator only generates a pulling force and does not generate a pushing force.

8. The two-degree-of-freedom rocking table for super-high test specimens according to claim 1, characterized by, The test rig is used for testing a pipe heat exchanger, and the size of the main frame of the test piece is 4 m x 4 m x 38 m.

9. The two-degree-of-freedom rocking table for super-high test specimens according to claim 1, characterized by, The test rig realizes single-freedom motion and two-freedom compound motion of the test piece by controlling the displacement of the four actuators.

10. The two-degree-of-freedom rocking table for super-high test specimens according to claim 1, characterized by, In the event of a control system failure, the electromagnetic reversing valve I is powered off to make the cartridge valve close, thereby stopping the motion of the test rig; After the test rig is stopped due to a fault, the electromagnetic reversing valve II is used to return the platform to the working zero position for troubleshooting.

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