Direct-acting soft friction testing apparatus
A test device and direct-acting technology, which is applied in the field of measuring instruments, can solve the problem of inability to obtain real-time access to elastic material surface deformation and lubrication medium distribution rules in the contact area, and achieve the effect of simple structure and improved efficiency.
Inactive Publication Date: 2012-06-27
CHINA UNIV OF PETROLEUM (BEIJING)
5 Cites 22 Cited by
AI-Extracted Technical Summary
Problems solved by technology
However, none of these testing machines can obtain the surface deformation of the elastic materia...
Method used
Described loading mechanism 3 comprises the vertical bearing seat 311 that is fixed on the supporting platform 1 by screw, and vertical rotating shaft 312 is rotatably arranged in described vertical bearing seat 311, and vertical rotating shaft 312 A U-shaped support 313 is arranged on the top of the top, and the approximate middle part of the loading beam 323 is hinged in the U-shaped support 313 at the top of the vertical rotation axis 312 through a horizontal axis 324 . The weight 331 is fixed on the loading end 325 of the loading beam 323 through a pre-tension spring 332 and a spring limiting nut 333 . One end of the loading beam 323 is an extension end 322, and the extension end 322 is formed as a screw rod. The balance weight 321 can be fixed on the end of the extension end 322 by screwing, and the rotation balance weight 321 can be adjusted on the extension end. position to achieve mass balance between the two ends of the weight loading beam 323 .
Direct motion type soft friction test device of the present invention can simulate the soft friction of oil and gas pipeline pigging, utilize microscope and image acquisition technology, obtain elastic sample (upper sample 344) and rigid sample (lower sample) in real time 222) The surface deformation of the elastic element in the contact area and the flow characteristics of the lubricating medium can simulate the microscopic flow characteristics when the pigging ball wipes the residual liquid (water) in the pipe; according to th...
Abstract
The invention relates to a direct-acting soft friction testing apparatus comprising a supporting stage. A lower sample fixing rack is arranged on the upper part of the supporting stage, and is connected with a driving mechanism. Under the driving of the driving mechanism, the fixing rack can move linearly in a plane. An upper sample assembly is arranged on the upper part of the lower sample fixing rack, and is connected to a loading mechanism which can apply a pressure downwards. A friction force detecting mechanism is connected with the upper sample assembly. Two samples with different elastic modulus are respectively fixed in the upper sample assembly and on the lower sample fixing rack. With the loading mechanism, the upper sample is pressed against the lower sample. The apparatus is advantaged in simple structure. Various testing parameters can be easily changed. When the lower sample is manufactured by using a transparent material, an elastic material surface deformation image and a residual liquid distribution image on a contact area can be acquired in real-time. Therefore, a solution is provided for optimizing selection of soft friction materials in complicated environments.
Application Domain
Using mechanical meansMaterial analysis
Technology Topic
Elastic modulusFriction test +4
Image
Examples
- Experimental program(1)
Example Embodiment
[0039] A direct-acting soft friction test device provided by the present invention includes: a support table; a lower sample holder, which is arranged on the upper part of the support table and is connected with a driving mechanism, which can be driven by the driving mechanism Move straight in the plane. The upper sample assembly is arranged on the upper part of the lower sample holder and is connected with a loading mechanism that can apply downward pressure; the friction force detection mechanism is arranged on the support table and is connected to the upper sample assembly Are connected; two samples with different elastic moduli are respectively fixed in the upper sample assembly and on the lower sample holder, and the upper sample abuts against the lower sample through the loading mechanism In the upper part, the friction force between the upper and lower samples is detected by the friction force detecting mechanism.
[0040] The present invention presses the upper sample on the lower sample and makes the lower sample move linearly to simulate the basic operation process of erasing residual water during pigging in the pipeline. The friction detection mechanism detects the upper and lower samples in real time. The friction value between the samples, and the detected value can be transmitted to the computer for analysis and calculation, so as to obtain the soft friction law of the pig clean water and the pig ball to wipe the residual water, so that the appropriate material can be selected. The pigging ball is formed, and the pigging operation is carried out at a suitable operating speed of the pigging operation to improve the operation efficiency.
[0041] Further, the driving mechanism is any linear driving mechanism of a nut screw, a rack and pinion or a hydraulic drive.
[0042] In a specific embodiment, the driving mechanism adopts a nut screw structure, which includes: a ball screw driven by a motor, a nut is fixed on the lower sample holder, and the nut is opposite to the ball screw. Connection, can drive the lower sample holder to move linearly along the length of the ball screw; and at least one guide rail is provided on the side of the ball screw, and the lower sample holder is provided with The sliding block connected with the guide rail has a limit switch at the end of the guide rail.
[0043] A feasible technical solution is that the loading mechanism includes: a loading beam, the loading beam is hinged on the pillar, one end of the loading beam is an extension end, the other end is a loading end, and a balance weight is provided at the extension end The upper end of the loading end is provided with a weight, and the lower end of the loading end is connected with the upper sample assembly.
[0044] Further, the pillar has a vertical bearing seat fixed on the support table, a vertical rotating shaft is rotatably arranged in the vertical bearing seat, and a U-shaped bracket is provided on the top of the vertical rotating shaft , The loading beam is hinged on the top of the vertical rotation shaft through a horizontal shaft. The invention can easily fix or disassemble the upper sample by rotating the loading beam arranged on the top of the vertical rotating shaft.
[0045] In a preferred embodiment, the upper sample assembly includes a C-shaped clamp with a downward opening, the C-shaped clamp is fixedly connected to the loading beam, and the upper sample is fixed at the opening of the C-shaped clamp. Inside.
[0046] Further, in order to improve the fixing reliability of the upper sample, at least one elastic slit may be provided on the inner concave surface of the C-shaped clamp, and the locking bolt penetrates the two corresponding side walls of the C-shaped clamp, and the The upper sample is fixed in the opening of the C-shaped clamp.
[0047] In addition, the friction force detection mechanism includes a tension and compression sensor and a sensor connecting rod, wherein one installation end surface of the tension and compression sensor is fixedly connected to the upper sample assembly, and the other installation end surface of the tension and compression sensor is connected to the upper sample assembly. The sensor connecting rod is fixed, and the sensor connecting rod is fixed on the vertical bearing seat.
[0048] The upper sample and the lower sample are respectively an elastic sample and a rigid sample, the elastic modulus of the elastic sample ranges from 0-5 GPa, and the elastic modulus of the rigid sample ranges from 10-300 Gpa; The lower part of the support platform is provided with an image acquisition device, and the image acquisition part thereof corresponds to the contact area of the upper and lower samples.
[0049] The lower sample holder has a connecting part connected with the driving mechanism, and a fixing frame for fixing the lower sample, the fixing frame is arranged on the side of the connecting part; the upper test The sample is an elastic sample with an elastic modulus in the range of 0-5 GPa, and the lower sample is a rigid sample with an elastic modulus in the range of 10-300 Gpa; preferably the lower sample is transparent glass, and the image acquisition The device is an inverted microscope, and the objective lens of the microscope is aligned with the contact area of the upper sample and the lower sample.
[0050] In order to have a clearer understanding of the technical features, objectives and effects of the present invention, the specific implementation, structure, features and effects of the direct-acting soft friction test device of the present invention will be described in detail below with reference to the drawings and preferred embodiments. Rear. In addition, through the description of the specific implementations, the technical means and effects of the present invention to achieve the predetermined purpose can be understood more deeply and concretely. However, the attached drawings are only for reference and illustration, and are not used to limit the present invention. .
[0051] figure 1 It is a schematic diagram of the three-dimensional structure of the direct-acting soft friction test device of the present invention; figure 2 It is a schematic front view of the direct-acting soft friction test device of the present invention; image 3 It is a schematic top view of the direct-acting soft friction test device of the present invention; Figure 4 It is a schematic diagram of the structure of the sample assembly on the direct-acting soft friction test device of the present invention.
[0052] As shown in the figure, the direct-acting soft friction test device proposed by the present invention includes: a supporting table 1; a lower sample holder 22, which is arranged on the upper part of the supporting table 1 and connected with the driving mechanism 2. Driven by the driving mechanism 2, it can move linearly in a plane. The upper sample assembly 34 is arranged on the upper part of the lower sample holder 22 and is connected to the loading mechanism 3 capable of applying downward pressure. The friction force detection mechanism 4 is arranged on the support table 1 and connected with the upper sample assembly 34. Two samples with different hardnesses are respectively fixed in the upper sample assembly 34 and on the lower sample holder 22, and the upper sample abuts on the lower sample through the loading mechanism 3, The friction force detection mechanism 4 detects the friction force between the upper and lower samples.
[0053] Wherein, the driving mechanism 2 may adopt any linear driving mechanism of a nut screw, a rack and pinion or a hydraulic drive.
[0054] Such as figure 1 , figure 2 , image 3 As shown, in this embodiment, the driving mechanism 2 adopts a nut screw mechanism, which includes a ball screw 216 driven by a motor, a nut 215 is fixed on the lower sample holder 22, and the nut 215 is connected to the ball screw 216 to drive the lower sample holder 22 to move linearly along the length of the ball screw 216, and at least one side of the ball screw 216 is provided A guide rail 213, the lower sample holder 22 is provided with a slider 214 connected to the guide rail 213, and a limit switch 219 is provided at the end of the guide rail 213. In this embodiment, in order to make the movement of the lower sample holder 22 stable, a guide rail 213 is respectively provided on both sides of the ball screw 216, and a limit switch 219 is provided at the end of one of the guide rails.
[0055] When a linear drive mechanism of other structure is used, it is enough to connect the lower sample holder 22 with the drive of the linear drive mechanism to ensure that the lower sample holder 22 moves linearly in a prescribed plane. The setting position is not restricted.
[0056] In a feasible technical solution, such as Figure 1 to Figure 3 As shown, the loading mechanism 3 includes: a loading beam 323 which is hingedly connected to a pillar, one end of the loading beam 323 is an extension end 322, the other end is a loading end 325, and the extension end 322 is provided There is a balance weight 321, the upper end of the loading end 325 is provided with a weight 331, and the lower end of the loading end 325 is connected with the upper sample assembly 34.
[0057] Wherein, the pillar has a vertical bearing seat 311 fixed on the support platform 1, a vertical rotating shaft 312 is rotatably arranged in the vertical bearing seat 311, and the top of the vertical rotating shaft 312 is arranged There is a U-shaped bracket 313, and the loading beam 323 is hinged on the top of the vertical rotating shaft 312 through a horizontal shaft 324.
[0058] Further, the upper sample assembly 34 includes a C-shaped clamp 343 with a downward opening, the C-shaped clamp 343 is fixedly connected to the loading beam 323, and the upper sample 344 is fixed on the C-shaped clamp 343. Inside the opening.
[0059] Wherein, the inner concave surface of the C-shaped clamp 343 is provided with at least one elastic slit 3431, and the locking bolt 342 penetrates the two corresponding side walls of the C-shaped clamp 343 to fix the upper sample 344 on the C-shaped clamp 343. -Shaped clamp 343 in the opening.
[0060] In a specific embodiment, the friction force detection mechanism 4 includes a tension and compression sensor 42 and a sensor connecting rod 41, wherein one mounting end surface of the tension and compression sensor 42 is fixedly connected to the C-shaped clamp 343, and the tension The other mounting end surface of the pressure sensor 42 is fixed to the sensor connecting rod 41, and the sensor connecting rod 41 is fixed on the vertical bearing seat 311.
[0061] In addition, the upper sample 344 and the lower sample 222 are respectively an elastic sample and a rigid sample, the elastic modulus of the elastic sample ranges from 0 to 5 GPa, and the elastic modulus of the rigid sample ranges from 10. ~300Gpa; An image acquisition device 5 is provided at the lower part of the support table 1, and the image acquisition part corresponds to the contact area of the upper and lower samples.
[0062] The lower sample fixing frame 22 has a connecting portion 221 connected to the driving mechanism 2 and a fixing frame 223 for fixing the lower sample 222, and the fixing frame 223 is provided on the connecting portion 221 Side. The upper sample 344 is an elastic sample with an elastic modulus ranging from 0 to 5 GPa, and the lower sample 222 is a rigid sample with an elastic modulus ranging from 10 to 300 Gpa. Preferably, the lower sample 222 is transparent glass, the image acquisition device 5 is an inverted microscope 51, and the image acquisition part objective lens 54 of the microscope 51 is aligned with the contact area of the upper sample 344 and the lower sample 222.
[0063] The direct-acting soft friction test device of the present invention can simulate the soft friction of oil and natural gas pipeline pigging, using microscope and image acquisition technology to obtain real-time contact of the elastic sample (upper sample 344) and rigid sample (lower sample 222) The surface deformation of the elastic element and the flow characteristics of the lubricating medium in the zone can simulate the microscopic flow characteristics of the pig ball when the residual liquid (water) in the pipe is wiped out; according to the parameters and laws obtained from the soft friction test, a reasonable pig operating speed is adopted , Choosing appropriate elastic materials can improve the efficiency of pipeline cleaning and maintenance such as pig operations in the oil and gas field.
[0064] The structure and working principle of the direct-acting soft friction test device of the present invention will be further described below in conjunction with a specific embodiment:
[0065] Such as figure 2 As shown, the direct-acting soft friction test device proposed by the present invention includes a support table 1, a driving mechanism 2 fixed on the support table and capable of producing linear movement, a loading mechanism 3, a friction force detection mechanism 4 and an inverted image acquisition device 5. The lower sample holder 22 is connected with the driving mechanism 2, and the upper sample assembly 34 is arranged on the upper part of the lower sample holder 22 and is connected with the loading mechanism 3 capable of applying downward pressure.
[0066] The driving mechanism 2 includes a motor bracket 211 fixed on the support table 1 and a DC motor. The DC motor drives the ball screw 216 to rotate through a coupling 212, and the ball screw 216 is supported by a bearing seat 218 and a rolling bearing 217 On the support 1. Such as figure 1 , 3 As shown, a guide rail 213 is respectively provided on both sides of the ball screw 216, both ends of the guide rail 213 are fixedly connected to the bearing housing 218, and a limit switch 219 is provided at the end of one of the guide rails 213 to prevent the nut 215 from overtaking Out the two ends of the ball screw 216.
[0067] The lower sample holder 22 has a connecting portion 221 and a fixing frame 223. A slider 214 and a nut 215 are provided at the lower part of the connecting portion 221. In this specific structure, the nut 215 and the slider 214 pass through A plurality of set screws are fixed at the lower part of the connecting portion 221 and are respectively connected with the ball screw 216 and the guide rail 213 of the driving mechanism 2. Driven by the DC motor and the ball screw 216, the nut 215 moves along the length of the ball screw 216, and the guide rail 213 plays a guiding role, so that the lower sample holder 22 can move horizontally smoothly. In addition, the rotation speed of the motor is controlled by the control mechanism, so that the linear movement speed of the slider 214 can be changed. Since the spiral transmission formed by the ball screw 216, the nut 215, and the slider 214 is an existing technology, it will not be repeated here.
[0068] In addition, the fixing frame 223 is arranged on the side of the connecting portion 221 to form a quadrilateral frame with a hollowed-out middle part. In order to facilitate the fixing of the lower sample 222, the side of the frame has a concave groove. The depth of the groove is greater than the thickness value of the lower sample 222, and the lower sample 222 of the quadrilateral shape can be fitted into the groove for fixing and positioning, so that the lower sample 222 is firmly stabilized on the lower sample fixing frame 22, Improve the reliability and stability of installation. And because the depth of the groove is greater than the thickness of the lower sample 222, the fixing frame 223 and the lower sample 222 form a groove with the lower sample 222 as the bottom surface, and a number of lubricating media can be accommodated in the groove, such as Crude oils with different viscosities, aqueous solutions with different pHs, etc., facilitate real-time research on the friction law of the upper sample 344 and the lower sample 222.
[0069] The loading mechanism 3 includes a vertical bearing seat 311 fixed on the support table 1 by screws, a vertical rotating shaft 312 is rotatably arranged in the vertical bearing seat 311, and is arranged on top of the vertical rotating shaft 312 There is a U-shaped bracket 313, and the substantially middle part of the loading beam 323 is hinged in the U-shaped bracket 313 on the top of the vertical rotating shaft 312 through a horizontal shaft 324. The weight 331 is fixed to the loading end 325 of the loading beam 323 via a pretension spring 332 and a spring limit nut 333. One end of the loading beam 323 is an extension end 322, and the extension end 322 is formed as a screw. The balance weight 321 can be fixed to the end of the extension end 322 through a threaded connection, and the balance weight 321 can be adjusted on the extension end by rotating the balance weight 321. To achieve the mass balance of the two ends of the weight loading beam 323.
[0070] Such as Figure 4 As shown, the upper sample assembly 34 includes a C-shaped clamp 343 that is fixed to the bottom of the loading end 325 of the loading beam 323 of the weight loading mechanism 3 by a transition rod 341; the upper sample 344 is locked The tightening bolt 342 is fixed in the C-shaped clamp 343. In order to improve the fixing reliability of the upper sample 344, a tiny elastic slit 3431 can be opened on the inner concave surface of the C-shaped clamp 343. When the locking bolt 342 is tightened, the C-shaped clamp 343 can be greatly elastically deformed. , Clamp the upper sample 344 firmly.
[0071] Figure 4 In the illustrated embodiment, the upper sample 344 is placed in the cylindrical hole of the C-shaped clamp 343, wherein the upper sample 344 is a cylinder, and a thin elastic material is wrapped around the cylindrical metal cylinder. Of course, the elastic material can also be directly made into a cylinder, and it can be directly installed in the C-shaped clamp 343. However, the shape of the upper sample 344 is not limited to this, and the upper sample 344 can be a sphere, a cylinder, a hexahedron, etc., as long as it can be firmly fixed in the upper sample assembly 34.
[0072] The friction force detection mechanism 4 includes a tension and compression sensor 42 and a sensor connecting rod 41. One of the installation ends of the tension and compression sensor 42 is fixed to the C-shaped clamp 343, and the other installation end of the tension and compression sensor 42 is connected to the sensor. The connecting rod 41 is fixed, and the other end of the sensor connecting rod 41 is fixed to the vertical bearing seat 311 of the aforementioned loading mechanism 3.
[0073] Wherein, the basic process of the tension and compression sensor 42 collecting friction force is that the aforementioned loading mechanism 3 sets a weight 331 of a certain weight at the loading end of the loading beam 323 to press the upper sample 344 against the lower sample 222 and start The aforementioned driving mechanism 2 moves the lower sample 222 linearly. The aforementioned lower sample 222 and upper sample 344 have a certain coefficient of friction. At this time, the friction force is transferred from the upper sample 344 to the C-shaped clamp 343. Since the C-shaped clamp 343 is connected to the loading beam 323, The friction force exerts a rotating force on the rotatable vertical rotating shaft 312 through the loading beam 323, and one end of the tension and compression sensor 42 is fixed to the C-shaped clamp 343, and the other end is fixed to the vertical bearing seat 311 through the sensor connecting rod 41 , The tension and compression sensor 42 fixed on the C-shaped clamp 343 finally collects the moving speed value of the lower sample 222 and the frictional force between the upper sample and the lower sample under the weight 331 placed on the mass. .
[0074] Wherein, when the magnitude of the friction force collected by the tension and compression sensor 42 is F, it is assumed that the weight of the weight 331 set at the loading end at this time is N. It can be calculated that the friction coefficient between the upper sample 344 and the lower sample 222 at this time is μ=F/N.
[0075] In this embodiment, the upper sample 344 is an elastic sample, and its elastic modulus ranges from 0 to 5 GPa, such as: polyurethane rubber material, nitrile rubber material, silicone rubber material, chloroether rubber material, polydimethylsiloxane Polydimethylsiloxane (PDMS); the lower sample 222 is made of rigid materials with an elastic modulus ranging from 10 to 300 GPa, such as transparent glass plates, transparent glass tiles, transparent plexiglass, ordinary iron plates, Ordinary steel plate. When the lower sample 222 is made of a transparent glass plate, the action behavior image of the soft friction contact area between the upper sample 344 and the lower sample 222 can be collected through the eyepiece of the microscope 51 placed at the lower part of the support table 1.
[0076] Wherein, the image acquisition device 5 includes an inverted microscope 51, a microscope support 53 fixed at the lower part of the support table 1, an image sensor 52 connected to the microscope, and the image sensor 52 is connected to a computer. The objective lens 54 of the inverted microscope 51 is relatively placed directly below the lower sample 222, and is aligned with the contact area between the upper and lower samples to collect soft friction microscopic images of the contact area.
[0077] The basic operation process of the direct-acting soft friction test device of the present invention for simulating the cleaning of residual water by the elastomer in the pipeline pigging operation is:
[0078] First, the preparations before the test:
[0079] The lower sample 222 of transparent glass material is installed on the fixed frame 223 of the lower sample holder 22, and the corresponding upper sample 344 is selected from the polyurethane material actually used in the pigging operation of the oil and gas pipeline. After the motor speed is set, that is, the moving speed of the lower sample holder 22, the weight 331 is placed on the loading end 325 of the aforementioned loading beam 323, and the nut 333 and the pre-tension spring 332 are used to pre-tighten and fix the upper sample. 344 presses against the upper surface of the lower sample 222. A layer of water film or several water droplets is artificially applied on the upper surface of the lower sample 222 made of transparent glass.
[0080] Because the accumulated water or residual water in the oil and gas pipeline is generally at the lowest point in the pipeline, the simulated water film or water drop must be on the upper surface of the lower sample 222 of transparent glass, so an inverted microscope must be used.
[0081] Second, start the direct-acting soft friction test:
[0082] Start the motor. The motor drives the ball screw 216 to rotate through the coupling 212. Driven by the ball screw 216, the nut 215 moves along the length of the ball screw 216, thereby driving the lower sample holder 22 to move horizontally back and forth. , The soft friction microscopic image of the contact area between the upper sample 344 and the lower sample 222 is collected by the objective lens 54 of the microscope 51 arranged at the lower part of the lower sample, and the collected image is transmitted to the computer for analysis through the image sensor 52. The sensor 42 transmits the detected frictional force between the upper and lower samples to the computer.
[0083] Third, the analysis of the test:
[0084] Because in the soft friction test of the lower sample 222 made of transparent glass and the upper sample 344 made of elastic material, the load weight of the weight 331 can be changed, and the moving speed of the lower sample holder 22 can also be changed. The material elastic modulus and surface roughness of sample 344. Under the conditions of the different parameters, the tension and compression sensor 42 of the friction detection mechanism 4 can collect a set of different friction forces, and the image sensor 52 can observe and collect the microscopic contact areas of the lower sample 222 and the upper sample 344 in real time. The action behavior includes the surface deformation image of the upper sample 344 made of elastic material, and the distribution law of the lubricating medium in the contact area.
[0085] Therefore, after completing the soft friction test of the clean water of the pipe cleaner and the cleaning ball to wipe the residual water, the soft friction law of the clean water of the pipe pig and the cleaning ball to wipe the residual water is obtained, which can be used to select appropriate Pigging operations with flexible materials, pigging operation speed, surface roughness of elastic materials, etc., improve the efficiency of oil and gas pipeline pigging operations.
[0086] The foregoing descriptions are only illustrative specific embodiments of the present invention, and are not used to limit the scope of the present invention. Any equivalent changes and modifications made by any person skilled in the art without departing from the concept and principle of the present invention shall fall within the protection scope of the present invention. Moreover, it should be noted that the various components of the present invention are not limited to the above-mentioned overall application. The technical features described in the specification of the present invention can be selected individually or used in combination according to actual needs. Therefore, the present invention Naturally, other combinations and specific applications related to the invention of this case are covered.
PUM
| Property | Measurement | Unit |
| Elastic modulus | 0.0 ~ 5.0 | GPa |
| Elastic modulus | 10.0 ~ 300.0 | GPa |
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