Indoor fine-grained soil material centrifugal screening treatment device and method

Abstract

The application provides an indoor fine-grained soil material centrifugal screening treatment device and method, a feeding port valve is arranged on the top of a material collecting box shell; coaxial linear screening outer barrels and screening inner barrels are arranged in the material collecting box shell; the screening outer barrels and the screening inner barrels are in the shape of a circular truncated cone, the wide opening faces upwards and is located below the feeding port valve; the side surfaces of the screening outer barrels and the screening inner barrels are surrounded by multiple fan-shaped ring pieces, and the adjacent fan-shaped ring pieces are provided with hollows which are respectively used as inner-layer discharge ports and outer-layer discharge ports; the screening inner barrels are further provided with horizontal grids at the hollows; the outer side of the screening outer barrels is provided with multiple material collecting partitions, and the connecting positions of each layer of the material collecting partitions and the material collecting box shell are provided with discharge port switches; a speed regulating motor is used for completing rotation energy input work; and a vacuum pump system is used for completing vacuumizing work in the material collecting box. The application can directly screen the mixed material as a whole, and directly improves the screening efficiency.

Description

TECHNICAL FIELD

[0001] The application provides an indoor fine granular soil material centrifugal screening processing device and method, and belongs to the technical field of material screening. BACKGROUND

[0002] In the design and filling process of earth-rock dams, wide-graded coarse-grained soil is often used as construction material for dam shells. Reliable determination of the mechanical property parameters of such soil material is a prerequisite for the technical feasibility of the design scheme of earth-rock dams. However, in the laboratory test equipment of limited size, it is impossible to carry out the property test of the original graded dam material. Therefore, the content of each particle group of the original graded dam material needs to be reasonably determined through particle analysis test, and then the content of each particle group of the test material after scaling is determined according to the scaling method and scaling ratio. Taking the similar grading method (scaling ratio 10:1) as an example, the deficiencies in the traditional screening method are illustrated.

[0003] (1) When carrying out indoor large-scale triaxial test (300 mm) on rockfill material with a maximum particle size of 500 mm, the maximum particle size of the indoor scaled material is 50 mm. When preparing the material indoors, the soil material below 50 mm needs to be screened from the original graded material. However, there is no 50 mm sieve in the indoor common screening device. Therefore, a custom-made sieve is needed to determine the corresponding particle group content.

[0004] (2) For the scaled material grading particle groups of the original graded material particle groups 60 mm-20 mm (coarse gravel), 20 mm-5 mm (medium gravel), and 2 mm-5 mm (fine gravel), the scaled material grading particle groups need to be accurately determined to 6 mm-2 mm, 2.0 mm-0.5 mm, and 0.2 mm-0.5 mm, respectively. According to the traditional test method, the soil material above 2 mm and the soil material below 2 mm need to be screened in different ways, and the screening efficiency is low. Moreover, it is difficult to accurately determine the scaled material particle groups with such small sizes (0.2 mm (there is no common sieve with a size of 0.2 mm)-0.5 mm) in the traditional screening test.

[0005] (3) In order to overcome the problem of the lack of sieves, the original graded interpolation method is often used to determine the particle group content of the scaled material. For example, there are 0.25 mm sieves and 0.5 mm sieves in the laboratory, and the particle group content of 0.25 mm-0.5 mm can be determined indoors. Therefore, the content of 2.5 mm-5 mm in the original grading needs to be determined. The particle group content of 2 mm-5 mm can be directly determined for the original grading, and the content of 2.5 mm-5 mm needs to be determined by linear interpolation or other methods. This method brings obvious errors.

[0006] The particle analysis test generally adopts sieve analysis method, density level method and pipette method. The sieve analysis method is generally used to obtain the soil with the particle size of 0.075 mm to 60 mm; the density meter method or the pipette method is generally used to obtain the soil with the particle size less than 0.075 mm. When the soil has coarse and fine particles, the sieve analysis method and the density meter method or the sieve analysis method and the pipette method should be combined, and the sieve analysis method is the closest method to the present application.

[0007] The sieve analysis method first needs to purchase or prefabricate a group of sieves with different fixed aperture sizes. Then, the soil material is preliminarily separated through a 2 mm sieve, and the soil material greater than 2 mm (coarse sieve separation) and the soil material less than 2 mm (fine sieve separation) are separated. Secondly, the sieves are stacked together in the order of decreasing aperture size.

[0008] For the soil material greater than 2 mm, the sieves are shaken in the order of decreasing aperture size; for the soil material less than 2 mm, the soil material is poured into the uppermost layer of the fine sieve, and the soil material is shaken for 10 to 15 minutes based on the above steps to complete the sieve separation of the soil material with the particle size of 0.075 mm to 60 mm.

[0009] In the process of determining the content of each particle group of the conventional reduced-scale material, there are mainly two problems:

[0010] (1) Since the standard sieve cannot adjust the aperture size, there is a certain error in determining the content of each particle group of the reduced-scale material, and the cost of the single sieve of the designed sieve is too high, and the sieve cannot be adjusted in time according to the actual demand. The content of each particle group of the conventional reduced-scale material needs to be determined by interpolation. When the indoor large-scale triaxial test is carried out with the scale ratio of 10:1, the particle group content of the reduced-scale material needs to be determined. For example, the particle group of the target reduced-scale material is 5 mm to 20 mm, the particle group content of the original particle group of 50 mm to 200 mm needs to be determined by reverse calculation according to the scale ratio. In the actual operation process, the particle group content of 50 mm to 60 mm in the particle group of 20 mm to 60 mm of the original particle group is determined by interpolation in the corresponding particle group curve, and the particle group content of 50 mm to 200 mm of the original particle group is determined by combining the particle group content of 60 mm to 200 mm of the original particle group, and finally the particle group content of 5 mm to 20 mm of the target reduced-scale material is determined by the scale ratio, and there is a certain error in the process.

[0011] (2) The particle group of the reduced-scale material is too small to be conveniently and quickly obtained by sieve separation. For example, when the indoor large-scale triaxial test is carried out with the scale ratio of 10:1, the control particle group of the coarse-grained soil on site is 2 mm to 5 mm, and the particle group of the reduced-scale material needs to be accurately to 0.2 mm to 0.5 mm in theory. The particle group cannot be quickly and massively obtained by the sieve separation method. SUMMARY

[0012] The present application utilizes the principle of centrifugal force to separate the soil material particle groups through the sieve barrel, thereby improving the efficiency and accuracy of determining the content of each particle group of the reduced scale material, and solving the problems of errors in determining the content of each particle group of the reduced scale material and the difficulty in screening due to too small particle size. The main advantages are:

[0013] (1) Directly overcome the difficulty and economic waste of customizing a sieve for some irregular particle groups. The sieve barrel is a circular cone sleeve, and the change in its radius is designed according to the particle diameter and specific gravity based on the principle of centrifugal force. Different particle groups can be effectively screened.

[0014] (2) The centrifugal screening test device does not need to separate the coarse and fine sieve groups and then adopt different methods for screening. It can directly screen the mixed material as a whole, directly improving the screening efficiency. The design of the circular cone sleeve allows the device to meet the discharge requirements during stable rotation.

[0015] The specific technical scheme is:

[0016] An indoor fine-grained soil centrifugal screening treatment device, comprising a speed regulation motor, a material collecting box, and a vacuum pump system.

[0017] The material collecting box comprises a material collecting box shell mounted on a base support, a feed inlet valve provided at the top of the material collecting box shell, and a coaxial linear sieve outer barrel and a sieve inner barrel provided inside the material collecting box shell. The sieve outer barrel and the sieve inner barrel are in the shape of a circular cone with a wide opening facing upwards and located below the feed inlet valve. The circular cone side surfaces of the sieve outer barrel and the sieve inner barrel are surrounded by multiple fan ring pieces, and the adjacent fan ring pieces are provided with hollows as inner and outer discharge ports, respectively. The sieve inner barrel is further provided with a horizontal grid at the hollow. The outer side of the sieve outer barrel is provided with multiple material collecting partitions, and each material collecting partition is provided with a discharge port switch at the connection with the material collecting box shell.

[0018] The speed regulation motor is used to complete the rotation energy input work. The speed regulation motor comprises a rotation speed controller, a motor, and an inner and outer cylinder asynchronous control valve. The rotation speed controller enables the sieve outer barrel and the sieve inner barrel to rotate at a constant angular velocity ω. The motor provides rotation kinetic energy, and the inner and outer cylinder asynchronous control valve enables the sieve outer barrel and the sieve inner barrel to be different, allowing the soil and rock material to pass through the horizontal grid and enter the material collecting partitions during operation.

[0019] The vacuum pump system is used to complete the vacuumization work inside the material collecting box. The vacuum pump system comprises a conduit, a pressure gauge, and a vacuum pump. The vacuum pump is connected to the feed inlet valve through the conduit and the pressure gauge.

[0020] An indoor fine-grained soil centrifugal screening treatment method using the indoor fine-grained soil centrifugal screening treatment device. The method comprises the following steps:

[0021] S1, device presetting and debugging; according to the specific gravity of soil particles, the motor rotating speed ω is set by a rotating speed controller, the feeding port valve is closed, the vacuum pump is started, the space in the aggregate tank shell is vacuumized, and the airtight test is carried out for one hour; after the airtight test is completed, the air pressure in the space in the aggregate tank shell is restored by the vacuum pump, and subsequent tests are prepared;

[0022] S2, loading; the feeding port valve is opened, the mixed graded soil and stone materials are poured into the inner layer barrel of the screening material, and then the feeding port valve is closed;

[0023] S3, vacuumizing; the vacuum pump is opened, and the space in the aggregate tank shell is vacuumized; when the air pressure table reaches 5% of the atmospheric pressure, the vacuum pump is stopped, and the test work can be carried out;

[0024] S4, centrifugal screening start; the motor is started, and the device starts rotating at the predetermined rotating speed ω;

[0025] S5, discharging; after the outer layer barrel of the screening material and the inner layer barrel of the screening material rotate stably for a period of time, the rotating speeds of the outer layer barrel of the screening material and the inner layer barrel of the screening material are adjusted by controlling the asynchronous control valve of the inner and outer cylinders, so that the soil and stone materials leak along the horizontal grid of the outer layer barrel of the screening material and the inner layer barrel of the screening material, and enter the aggregate baffle;

[0026] S6, restoring atmospheric pressure; the vacuum pump is opened, and the air in the space in the aggregate tank shell is supplemented; when the air pressure table reaches 100% of the atmospheric pressure, the vacuum pump is stopped;

[0027] S7, taking the materials in the particle groups; the discharge port switch is opened, and the screened soil materials in the aggregate baffle are taken out.

[0028] The technical scheme of the present application has the following beneficial effects:

[0029] (1) The difficulties and economic waste of customizing a sieve for some unconventional particle groups are directly overcome, and the screening work of different particle groups can be effectively realized according to the needs.

[0030] (2) The centrifugal screening test device can directly screen the mixed materials as a whole without separating the coarse sieve and the fine sieve groups and adopting different screening methods, and the screening efficiency is directly improved. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a structural schematic diagram of the present application;

[0032] Figure 2 is a structural schematic diagram of the inner layer barrel of the screening material of the present application;

[0033] Figure 3 is a structural schematic diagram of the outer layer barrel of the screening material of the present application;

[0034] Figure 4is the inner and outer cylinder asynchronous control valve adjustment rotating speed state of the present application;

[0035] Figure 5 is the centrifugal screening state of the present application;

[0036] Figure 6 is the design principle schematic diagram of the present application. DETAILED DESCRIPTION

[0037] The specific technical solutions of the present application are illustrated in combination with the embodiments.

[0038] An indoor fine-grained soil material centrifugal screening processing device, the basic principle is shown in Figure 1 , mainly composed of a speed regulating motor, a material collecting box, and a vacuum pump. The specific components are introduced as follows:

[0039] The material collecting box is mainly composed of a material collecting box shell 1, a discharge port switch 2, a screening outer barrel 3, a screening inner barrel 4, a material collecting partition 5, and a feeding port valve 10. The material collecting box shell 1 is installed on a base support 6; the material collecting box shell 1 is provided with a feeding port valve 10 at the top; the material collecting box shell 1 is provided with coaxial linear screening outer barrel 3 and screening inner barrel 4; the screening outer barrel 3 is shown in Figure 3 , and the screening inner barrel 4 is shown in Figure 2 . The screening outer barrel 3 and the screening inner barrel 4 are in the shape of a circular truncated cone, with the wide opening facing upwards and located below the feeding port valve 10; the side of the circular truncated cone of the screening outer barrel 3 and the screening inner barrel 4 is surrounded by multiple fan-shaped ring pieces, and the adjacent fan-shaped ring pieces are provided with hollows as the inner layer discharge port 14 and the outer layer discharge port 15, respectively; the screening inner barrel 4 is further provided with a horizontal grid at the hollow; the outer side of the screening outer barrel 3 is provided with multiple layers of material collecting partitions 5, and each layer of material collecting partition 5 is provided with a discharge port switch 2 at the connection with the material collecting box shell 1;

[0040] The speed regulating motor is mainly composed of a rotating speed controller 9, a motor 8, and an inner and outer cylinder asynchronous control valve 7. This component mainly completes the input of rotating energy. The rotating speed controller mainly realizes the uniform rotation of the screening outer barrel 3 and the screening inner barrel 4 at a certain angular velocity ω, as shown in Figure 4 ; the motor 8 provides rotating kinetic energy, and the inner and outer cylinder asynchronous control valve 7 realizes the difference between the screening outer barrel 3 and the screening inner barrel 4, which can make the soil and stone materials enter the material collecting partition 5 through the horizontal grid during operation, as shown in Figure 5 .

[0041] The soil and stone material loading work is mainly completed by the feeding port valve 10 and the screening inner barrel 4 equipment; the soil screening work is mainly completed by the screening outer barrel 3 and the screening inner barrel 4 equipment; and the discharging work is mainly completed by the discharge port switch 2, the material collecting partition 5, and the feeding port valve 10 equipment.

[0042] The vacuum pump is mainly composed of a conduit 11, a pressure gauge 12 and a vacuum pump 13. The assembly is mainly used to complete the vacuumization of the inside of the aggregate tank.

[0043] The indoor fine-grained soil centrifugal screening treatment method:

[0044] S1, equipment presetting and debugging. According to the specific gravity of soil particles, the motor 8 rotating speed ω is set through the rotating speed controller 9, the feed inlet valve 10 is closed, the vacuum pump 13 is started, the space inside the aggregate tank shell 1 is vacuumized, and airtight test is carried out for one hour to test the airtightness of the equipment. After the airtight test is completed, the air pressure in the space inside the aggregate tank shell 1 is restored through the vacuum pump 13, and the subsequent test is prepared;

[0045] S2, loading. The mixed graded soil and stone materials are poured into the inner layer barrel 4 of the screening material, and then the feed inlet valve 10 is closed;

[0046] S3, vacuumizing. The vacuum pump 13 is started to vacuumize the space inside the aggregate tank shell 1. When the pressure gauge 12 reaches 5% of the atmospheric pressure, the vacuum pump 13 is stopped, and the test work can be carried out;

[0047] S4, centrifugal screening start. The motor 8 is started, and the equipment starts to rotate at the predetermined rotating speed ω;

[0048] S5, discharging. After the outer layer barrel 3 and the inner layer barrel 4 of the screening material rotate stably for a period of time, the rotating speed of the outer layer barrel 3 and the inner layer barrel 4 of the screening material is adjusted through the asynchronous control valve 7 to make the soil and stone materials leak along the horizontal grid of the outer layer barrel 3 and the inner layer barrel 4 of the screening material, and enter the aggregate baffle 5;

[0049] S6, restoring atmospheric pressure. The vacuum pump 13 is opened to supplement the air in the aggregate tank shell 1. When the pressure gauge 12 reaches 100% of the atmospheric pressure, the vacuum pump 13 is stopped;

[0050] S7, particle group taking. The discharging opening switch 2 is opened to take out the screened soil materials in the aggregate baffle 5.

[0051] The design core and principle diagram are shown in Figure 6 :

[0052] F c = m g ω 2 r(h) (1)

[0053] G = m g g (2)

[0054] f f = μF N (3)

[0055] F N = G cos θ + Fc sinθ (4)

[0056] r(h) = r0 + h cotθ (5)

[0057] F c - centrifugal force, N; ω - test device rotation speed;

[0058] G - gravity, N; r(h) - inner layer barrel radius of the sieve material, which is the height h of the cylinder and the radius of the inner barrel bottom

[0059] f f - friction, N; function of r0.

[0060] F N - normal stress, N; g - gravity acceleration, 9.81 m / s 2 ;

[0061] θ - inclination of the cylinder wall;

[0062] m g - mass of soil particles; μ - maximum static friction coefficient, for example, the friction coefficient between a steel plate and a block stone is 0.8.

[0063] Figure 6 The test principle of the centrifugal sieve test device for fine-grained soil is shown, and the force state of soil particles is shown in equations (1) to (4). When the test starts, all particles are accumulated at the bottom of the inner layer barrel of the sieve material, and with the operation of the speed regulation motor, the soil particles are rolled to the side wall under the action of the centrifugal force. When entering the stable rotation, the soil particles enter the force balance state under the action of the centrifugal force, the self-weight load and the friction, and the particles are stably rotated at a certain radius r(h). In the discharge stage, with the start of the inner and outer cylinder asynchronous control valve, the inner and outer cylinders produce a phase difference, the soil particles slide into the material collecting baffle, and finally the sieving work is completed.

[0064] The inner and outer cylinder asynchronous control valve is used in the device, and by adjusting the speed difference between the inner and outer cylinders, the horizontal grid of the sieve outer barrel and the sieve inner barrel is leaked, and the discharge operation is completed. Other control systems such as solenoid valves can also be used.

[0065] This embodiment reduces air resistance in the form of a vacuum pump. It is also feasible when using a saturated method to reduce air resistance.

Claims

1. An indoor fine-grained soil material centrifugal screening treatment device, characterized by, Including speed-regulating motor, aggregate tank, vacuum pump system; The aggregate tank includes an aggregate tank shell (1) installed on a base support (6); the aggregate tank shell (1) is provided with an inlet valve (10) at the top; the aggregate tank shell (1) is provided with coaxial linear screening outer barrel (3) and screening inner barrel (4); the screening outer barrel (3) and the screening inner barrel (4) are in the shape of a circular truncated cone, with the wide opening facing upwards and located below the inlet valve (10); the side of the circular truncated cone of the screening outer barrel (3) and the screening inner barrel (4) is surrounded by multiple fan-shaped ring pieces, with a hollow space between adjacent fan-shaped ring pieces, which are respectively used as an inner outlet (14) and an outer outlet (15); the screening inner barrel (4) is further provided with a horizontal grid at the hollow space; the outer side of the screening outer barrel (3) is provided with multiple aggregate separation plates (5), and each aggregate separation plate (5) is provided with an outlet switch (2) at the connection with the aggregate tank shell (1); The speed-regulating motor is used to complete the input of rotational energy; The vacuum pump system is used to complete the vacuumization of the inside of the aggregate tank; The speed-regulating motor comprises a rotating speed controller (9), a motor (8) and an inner-outer cylinder asynchronous control valve (7); the rotating speed controller (9) realizes that the screening outer layer barrel (3) and the screening inner layer barrel (4) rotate at a certain angular speed ; the motor (8) provides rotating kinetic energy; the inner-outer cylinder asynchronous control valve (7) realizes that the screening outer layer barrel (3) and the screening inner layer barrel (4) are different, so that the earth and stone materials pass through the horizontal grid into the material collecting baffle (5) during operation. The vacuum pump system includes a conduit (11), a pressure gauge (12) and a vacuum pump (13), and the vacuum pump (13) is connected to the inlet valve (10) through the conduit (11) and the pressure gauge (12).

2. A method of indoor fine-grained soil material centrifugal screening treatment, characterized in that, The method includes the following steps: S1, device preset and debugging; according to the specific gravity of soil particles, the motor (8) speed is set by the speed controller (9) Close the feed inlet valve (10) and start the vacuum pump (13) to vacuum the space inside the aggregate tank shell (1), and seal it for one hour to test the sealing of the equipment. After the sealing test is completed, restore the air pressure in the space inside the aggregate tank shell (1) through the vacuum pump (13) to prepare for subsequent tests; S2, loading; opening the inlet valve (10), pouring the mixed graded soil and stone into the screening inner barrel (4), and then closing the inlet valve (10); S3, vacuumizing; opening the vacuum pump (13) to perform vacuum treatment on the space inside the aggregate tank shell (1); when the pressure gauge (12) reaches 5% of atmospheric pressure, stop the vacuum pump (13), and the test work can be carried out; S4, centrifugal screening start; start the motor (8), the equipment according to the established speed Start rotating; S5, discharging; after the screening outer barrel (3) and the screening inner barrel (4) rotate stably for a period of time, the rotation speed of the screening outer barrel (3) and the screening inner barrel (4) is adjusted by controlling the asynchronous control valve (7) to make the soil and stone leak along the horizontal grid of the screening outer barrel (3) and the screening inner barrel (4) and enter the aggregate separation plate (5); S6, restoring atmospheric pressure; opening the vacuum pump (13) to supplement the air inside the aggregate tank shell (1); when the pressure gauge (12) reaches 100% of atmospheric pressure, stop the vacuum pump (13); S7, taking the screened soil in the aggregate separation plate (5) by opening the outlet switch (2).

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