Instrument and method for detecting equivalent elasticity of rubber particles on ground layer of synthetic material playground

Abstract

The invention discloses an instrument and a method for detecting the equivalent elasticity of rubber particles of a synthetic material playground surface layer, and solves the problem of lack of an instrument and a method for detecting the elasticity of the rubber particles of the synthetic material surface layer paved on the playground. The relative height of standard rubber particles with specific high polymer content, specific particle size and specific mass after pre-pressing in a container is taken as a reference, and is compared with the rebound value of the rubber particles to be tested under the same test condition, so that the equivalent elasticity of the rubber particles to be tested is obtained.

Description

Technical Field

[0001] The invention relates to an instrument and method for detecting the equivalent elasticity of rubber particles in a synthetic material sports field surface layer. Background Art

[0002] The synthetic material surface has good elasticity, high compressive strength, appropriate hardness, stable physical properties, wear resistance and non-slip, flexible design, convenient maintenance, simple construction, bright color, strong UV resistance and aging resistance, etc. It has become the internationally recognized best all-weather indoor and outdoor sports ground floor material and is widely used. The synthetic material surface runway contains polyurethane prepolymer, mixed polyether, waste tire rubber, EPDM rubber particles or PU particles, pigments, additives, fillers, etc. Rubber particles, as the constituent particles of the synthetic material surface layer, are elastomers prepared by blending plastics and rubber. In terms of technology, they are particles obtained by extrusion granulation or crushing granulation.

[0003] The national standard GB36246-2018 sets limits on the organic composition, harmful substance limits and volatile gases of the raw material particles of sports venues with synthetic material surfaces, but does not give exact regulations on the elastic properties of the particles. The high or low content of organic matter in the rubber particles of the synthetic material surface does not represent the quality of the elastic properties. When athletes exercise on a surface with poor elasticity, it is easy to cause damage to the joints, affecting their athletic performance. Summary of the invention

[0004] The invention provides an instrument and method for testing the equivalent elasticity of rubber particles in the surface layer of synthetic material sports field, so as to test the elasticity of rubber particles in the surface layer of synthetic material laid on various sports fields.

[0005] On the first aspect, a method for detecting the equivalent elasticity of rubber particles in the surface layer of a synthetic material sports field is proposed, comprising: taking the relative height of standard rubber particles with a specific polymer content, a specific particle size and a specific mass after pre-compression in a container as a reference, and comparing it with the rebound value measured under the same test conditions of the rubber particles to be tested, so as to obtain the equivalent elasticity of the rubber particles to be tested.

[0006] In some examples, the relative height is 22.75 mm.

[0007] In some examples, the polymer content of the standard rubber particles is 20%, the particle size is 1.8 mm to 2.2 mm, the mass is 30 g, the container diameter is 45 mm, and the pre-pressing pressure of the standard rubber particles is 100 kg.

[0008] In a second aspect, an instrument for detecting the equivalent elasticity of rubber particles in a synthetic material sports field surface is provided, comprising: a test table; a particle container for accommodating rubber particles, which is located on the test table; a lower fixture, which is located at the bottom of the particle container and is used to cooperate in adjusting the position of the particle container; a screw rod, which is arranged vertically and perpendicular to the test table, and the nut of the screw rod is connected to a transversely arranged main shaft; an upper fixture, which is installed on the main shaft and is located above the particle container, and can be extended into the particle container to pre-press the rubber particles under the drive of the screw rod; a pressure sensor, which is located between the upper fixture and the main shaft, and senses the pressure of the rubber particles in the particle container pre-pressed by the upper fixture; and a controller, which is configured to: cause the screw rod to drive the upper fixture to enter the particle container to pre-press the rubber particles, sense the pressure through the pressure sensor, and when the pre-pressing time and pressure reach the set value, cause the screw rod to drive the upper fixture to retreat, and when the pressure sensor senses that the pressure is 0, obtain the rebound value of the rubber particles based on the retreat distance of the upper fixture, and compare the rebound value with the reference value to obtain the equivalent elasticity of the rubber particles.

[0009] In some examples, the reference value is 22.75 mm.

[0010] In some examples, the reference value is the relative height of rubber particles with a mass of 30 g, a particle diameter of 1.8 mm to 2.2 mm, and a polymer content of 20% after being pre-pressed with 100 kg in a particle container with a diameter of 45 mm.

[0011] In some examples, a guide rail is provided on the test table to guide the movement of the lower jig, and the lower jig can move under the guidance of the guide rail to adjust the particle container to align it with the upper jig.

[0012] In some examples, the controller is connected to a display screen configured to display a combination of one or more of the following information: pressure of pre-pressing rubber particles, time of pre-pressing rubber particles, a baseline value, a rebound value of rubber particles, equivalent elasticity of rubber particles, and movement speed of the upper fixture.

[0013] In some examples, the rubber particles to be tested are pre-pressed at a certain speed for a set time using a first standard pressure, then the pre-pressing is stopped and the set time is waited, then the rubber particles to be tested are pre-pressed at a certain speed for a set time using a second standard pressure, and finally the rebound value of the rubber particles to be tested is measured. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of an instrument for detecting the considerable elasticity of synthetic rubber particles provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0015] The instrument and method for detecting the equivalent elasticity of rubber particles in the surface layer of synthetic material sports field of the present invention are applicable to rubber particles used in synthetic material surface layers on all types of sports fields and trails, including but not limited to bottom rubber particles, surface rubber particles and filling rubber particles used in synthetic material surface layers.

[0016] Quite elasticity is the comparison between the rebound value of rubber particles after being compressed and the benchmark value.

[0017] In one embodiment, the equivalent elasticity is a comparison of the relative height (also referred to as the benchmark value) of standard rubber particles with a specific polymer content, a specific particle size and a specific mass after pre-compression in a particle container with reference to the rebound values ​​of rubber particles with other polymer contents measured under the same test conditions. For example, the benchmark value of the equivalent elasticity is a comparison of the rebound values ​​of rubber particles with other polymer contents measured under the same test conditions with reference to the relative height of 22.75 mm after pre-compression of 100 kg in a particle container with a diameter of 45 mm and a depth of 35 mm using a standard particle sample with a 20% polymer content and a screened particle size of 1.8 mm to 2.2 mm and a mass of 30 g, and with reference to the rebound values ​​of rubber particles with other polymer contents measured under the same test conditions.

[0018] Figure 1 An instrument for detecting the equivalent elasticity of rubber particles in the surface layer of a synthetic material sports field is shown. The instrument comprises: a visual safety window 1, a pressure sensor 2, an upper fixture 3, a particle container 4, a lower fixture 5, a screw rod 6, and a stepping motor 7.

[0019] The upper jig 3 and the lower jig 5 assist in locating the position of the particle container 4 and compressing the rubber particles in the particle container 4. The particle container 4 is cylindrical and is used to accommodate rubber particles. The lower jig 5 is located at the bottom of the particle container 4. A pair of guide rails 12 are provided on the test table 13 of the instrument, and the lower jig 5 can slide on the guide rails 12 to adjust the position of the particle container 4 so that it is aligned with the upper jig 3. That is, the lower jig 5 is a slider that cooperates with the guide rails 12. In one embodiment, the lower jig 5 is a portion extending from the bottom of the particle container 4, that is, the particle container lower jig 5 is integrated with the particle container 4.

[0020] The screw rod 6 is arranged vertically, perpendicular to the test table 13, and driven by a stepper motor 7. In one embodiment, the screw rod 6 adopts a C5 grade ground screw rod. The nut of the screw rod 6 is connected to a transversely arranged main shaft, and the upper fixture 3 located above the particle container 4 is installed on the main shaft. A pressure sensor 2 is arranged between the upper fixture 3 and the main shaft. Driven by the stepper motor 7, the screw rod 6 can drive the upper fixture 3 to enter the particle container 4 to pre-press the rubber particles. The pressure sensor 2 senses the pressure. After the pre-pressing is completed, the screw rod 6 drives the upper fixture 3 to retreat and break contact with the rubber particles. In appearance, the upper fixture 3 is roughly cylindrical.

[0021] The upper fixture 3 , the particle container 4 , the lower fixture 5 and the test table 13 may be made of stainless steel.

[0022] The instrument also includes a control system, which controls the movement of the upper fixture 3 and the pressure of the upper fixture 3 on the rubber particles. The control system includes a controller, an encoder, a limit switch, a stepper motor drive circuit, an emergency stop switch 9, an operation button 10 and a display screen 11. The controller is connected to the limit switch, the stepper motor drive circuit, the emergency stop switch 9, the operation button 10 and the display screen 11 to collect signals from each part or control each part.

[0023] The controller is configured to perform the following steps: sending a signal to the stepper motor drive circuit to cause the lead screw 6 to drive the upper fixture 3 to enter the particle container 4 to pre-press the rubber particles, sensing the pressure through the pressure sensor 2, and when the pre-pressing time and pressure reach the set value, causing the lead screw 6 to drive the upper fixture 3 to retreat (the rubber particles will rebound), using the encoder to monitor the number of rotations and angles of the lead screw 6, and when the pressure sensor 2 senses that the pressure is 0 (that is, the upper fixture 3 is separated from the rubber particles), the distance that the upper fixture 3 retreats is calculated based on the lead of the lead screw 6 and the number of rotations and angle data of the lead screw 6 collected by the encoder (this distance is the rebound value of the rubber particles), and the rebound value is compared with the reference value to obtain the equivalent elasticity of the rubber particles.

[0024] The limit switches are set at the two extreme positions of the upper and lower movements of the upper jig 3. When it senses that the upper jig 3 has moved to the extreme position, the controller sends a command to the stepper motor drive circuit to stop the upper jig 3 from moving, thereby avoiding collision damage to the pressure sensor 2, the upper jig 3, the particle container 4, etc.

[0025] When the emergency stop switch 9 is pressed, the controller sends a command to the stepper motor drive circuit to stop the upper fixture 3 from moving.

[0026] There may be multiple operation buttons 10, including but not limited to: a button for adjusting the rising distance of the upper fixture 3, a button for adjusting the descending distance of the upper fixture 3, a button for adjusting the pre-pressing pressure of the rubber particles of the upper fixture 3, and a button for adjusting the pre-pressing time of the rubber particles of the upper fixture 3.

[0027] The display screen 11 displays a combination of one or more of the following information including but not limited to: the pressure of pre-pressing the rubber particles, the time of pre-pressing the rubber particles, the reference value, the rebound value of the rubber particles, the equivalent elasticity of the rubber particles, and the movement speed of the upper fixture.

[0028] The instrument can also be connected to a computer to control the movement of the upper fixture on the computer, such as controlling the position of the upper fixture, the pre-pressure on the rubber particles, and the pre-pressure time of the rubber particles. The information displayed on the display screen 11 can also be transmitted to the computer for display and storage.

[0029] In addition, a base 8 is provided at the bottom of the instrument. In order to ensure the safety of the test, a fence is provided around the test table 13, and a visual safety window 1 that can be opened is left in the fence. The user can observe the test process through the visual safety window 1, and the visual safety window 1 can be opened to take and place the particle container 4.

[0030] The following is a method for testing the equivalent elasticity of rubber particles in the surface layer of a synthetic material sports field. The required equipment includes: a standard sieve, a shaking sieve machine, an electronic balance, and the instrument for testing the equivalent elasticity of rubber particles in the surface layer of a synthetic material sports field of the present invention.

[0031] Standard sieve: in accordance with GB / T 6003.1-2022 standard, with apertures of 2.2mm and 4.0mm.

[0032] Shaking screen machine: vibration frequency is 140 times / min-160 times / min, vibration amplitude is 3mm-6mm, shaking frequency is 200 times / min-240 times / min, vibration amplitude is 12mm-13mm.

[0033] Electronic balance: accuracy is 0.1g.

[0034] Instrument for testing the equivalent elasticity of rubber particles in the surface layer of synthetic sports fields: the maximum load of the pressure sensor is (200±1)kg, and the accuracy is ±0.5%; the diameter of the upper fixture is 45mm, and the thickness is 18mm; the inner diameter of the particle container is 45mm, the thickness is: 40mm, and the depth is 35mm; the clearance between the upper fixture and the particle container is 0.05mm.

[0035] According to the "General Rules for Sampling and Inspection of Uniform Bulk Material" (GB / T 13732-2009), 2.5kg of rubber particles to be tested are sampled. The standard sieves are assembled on the shaker in the manner of large-aperture standard sieve on top and small-aperture standard sieve on the bottom. The weighed rubber particles are placed in the large-aperture standard sieve, and the cover and bottom plate are assembled. After shaking on the shaker for 3 minutes, 30 grams of particles with a particle size of 1.8mm to 2.2mm after screening are selected as samples for equivalent elasticity test.

[0036] Put the selected sample (rubber particles) into the particle container 4, assemble the lower fixture 5 at the bottom of the particle container 4 onto the track 12, adjust the position of the particle container 4 to align it with the upper fixture 3, set the test standard (pre-pressing pressure of rubber particles, pre-pressing time of rubber particles), start the instrument to start the test, pre-press the sample (rubber particles) according to the set test standard, and measure the rebound value of the sample (rubber particles) after the pre-pressing is completed. Compare the rebound value with the benchmark value to calculate the equivalent elasticity of the sample (rubber particles). Each sample is tested 3 times and the average value is taken as the result.

[0037] In another real-time method, the rubber particles to be tested are pre-pressed at a certain speed for a set time using the first standard pressure, then the pre-pressing is stopped and the set time is waited, and then the rubber particles to be tested are pre-pressed at a certain speed for a set time using the second standard pressure, and finally the rebound value of the rubber particles to be tested is measured. For example, the rubber particles are pre-pressed at a speed of 300mm / min using a pressure of 100kg, and then the upper fixture is raised to the set distance and waited for another 60s, and then the rubber particles are pre-pressed at a speed of 300mm / min using a pressure of 70kg, and finally the rebound value of the rubber particles is measured.

[0038] The rebound rate (equivalent elasticity) of the rubber particles in the synthetic material sports surface layer is calculated according to formula (1), and the data is accurate to 2 decimal places.

[0039]

[0040] Where: R m -----Resilience rate of synthetic rubber particles, unit: %, H f H is the rebound height (rebound value), unit: mm; i is a reference value of considerable elasticity, in mm. In one embodiment, the reference value H i The relative height of particles with a mass of 30g, a particle size of 1.8mm to 2.2mm, and a rubber content of 20% after being pre-pressed with 100kg in a container with a diameter of 50mm is 22.75mm.

Claims

1. A method for detecting the equivalent elasticity of rubber particles in the surface layer of a synthetic material sports field, characterized in that: include: The relative height of standard rubber particles with specific polymer content, specific particle size and specific mass after pre-compression in a container is used as a reference and compared with the rebound value measured by the rubber particles to be tested under the same test conditions to obtain the equivalent elasticity of the rubber particles to be tested.

2. The method for detecting the equivalent elasticity of rubber particles in the surface layer of a synthetic material sports field according to claim 1, characterized in that: The relative height is 22.75mm.

3. The method for detecting the equivalent elasticity of rubber particles in the surface layer of a synthetic material sports field according to claim 2, characterized in that: The polymer content of the standard rubber particles is 20%, the particle size is 1.8 mm to 2.2 mm, the mass is 30 g, the container diameter is 45 mm, and the pre-compression pressure of the standard rubber particles is 100 kg.

4. The method for detecting the equivalent elasticity of rubber particles in the surface layer of a synthetic material sports field according to claim 1, 2 or 3, characterized in that: First, use the first standard pressure to pre-press the rubber particles to be tested at a certain speed for a set time, then stop pre-pressing and wait for the set time, then use the second standard pressure to pre-press the rubber particles to be tested at a certain speed for a set time, and finally measure the rebound value of the rubber particles to be tested.

5. An instrument for testing the equivalent elasticity of rubber particles in the surface layer of a synthetic material sports field, characterized in that: include: Test bench; a particle container for containing rubber particles, which is located on the test table; A lower fixture, which is located at the bottom of the particle container and is used to adjust the position of the particle container; A screw rod is arranged vertically and perpendicular to the test table, and a nut of the screw rod is connected to a transversely arranged main shaft; The upper fixture is installed on the main shaft and is located above the particle container. Driven by the screw rod, it can extend into the particle container to pre-press the rubber particles. A pressure sensor, located between the upper fixture and the spindle, sensing the pressure of the upper fixture pre-pressing the rubber particles; and The controller is configured to: enable the screw rod to drive the upper fixture into the particle container to pre-press the rubber particles, sense the pressure through the pressure sensor, and when the pre-pressing time and pressure reach the set value, enable the screw rod to drive the upper fixture to retreat, and when the pressure sensor senses that the pressure is 0, obtain the rebound value of the rubber particles based on the retreat distance of the upper fixture, and compare the rebound value with the benchmark value to obtain the equivalent elasticity of the rubber particles.

6. The instrument for testing the equivalent elasticity of rubber particles in the surface layer of a synthetic material sports field according to claim 5, characterized in that: The benchmark value is 22.75mm.

7. The instrument for testing the equivalent elasticity of rubber particles in the surface layer of a synthetic material sports field according to claim 5, characterized in that: The benchmark value is the relative height of rubber particles with a mass of 30g, a particle size of 1.8mm to 2.2mm, and a polymer content of 20% after being pre-compressed with 100kg in a particle container with a diameter of 45mm.

8. The instrument for testing the equivalent elasticity of rubber particles in the surface layer of synthetic material sports field according to claim 5, characterized in that: The test table is provided with a guide rail for guiding the movement of the lower fixture. The lower fixture can move under the guidance of the guide rail to adjust the particle container so that it is aligned with the upper fixture.

9. The instrument for testing the equivalent elasticity of rubber particles in the surface layer of a synthetic material sports field according to claim 5, characterized in that: The controller is connected to a display screen, which is configured to display a combination of one or more of the following information: pressure of pre-pressing rubber particles, time of pre-pressing rubber particles, reference value, rebound value of rubber particles, equivalent elasticity of rubber particles, and movement speed of the upper fixture.

10. The instrument for testing the equivalent elasticity of rubber particles in the surface layer of synthetic material sports field according to claim 5, characterized in that: First, use the first standard pressure to pre-press the rubber particles to be tested at a certain speed for a set time, then stop pre-pressing and wait for the set time, then use the second standard pressure to pre-press the rubber particles to be tested at a certain speed for a set time, and finally measure the rebound value of the rubber particles to be tested.

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