Wet-type guniting bullet reducing and dust falling device

Abstract

The invention discloses a wet-type guniting bullet reducing and dust falling device which comprises a device body, the device body is a cylinder with a through hole along the axis, an inner cavity is formed in the device body, and the inner cavity is formed by sequentially communicating a medium inlet, a flow guide cavity, an inner confluence cavity, a rectification cavity, an acceleration cavity and a medium ring outlet. The through hole is used for containing a concrete wet-type guniting nozzle, and a medium is accelerated by the accelerating cavity to form a medium curtain at the front end of the device body through the medium ring outlet. The device is integrally printed through the 3D printing technology, the size is small, the integration degree is high, even and good sealing performance is guaranteed, meanwhile, installation is convenient and fast, the jet flow diffusion angle of concrete wet type guniting operation is reduced, and dust falling and dust isolation are effectively achieved.

Description

Technical Field

[0001] The invention relates to the technical field of shotcrete, in particular to a wet-type shotcrete reduction and dust suppression device. Background Art

[0002] Shotcrete, also known as sprayed concrete, is a construction technique that uses spraying equipment to spray pre-mixed concrete onto surfaces that require reinforcement, repair, or protection. It is widely used in underground projects, tunnels, rock support, slope protection, and restoration projects. However, during the spraying process, dust concentrations often remain high. Due to its high allergenicity, fineness, and corrosive properties, dust poses a serious threat to the health of on-site construction workers, reduces the service life of on-site machinery, increases equipment maintenance costs, and hinders construction progress. Existing patents such as CN 220791248 U disclose a nozzle and concrete spraying device for spraying concrete, which discloses that multiple spray nozzles are arranged around the spray nozzle to remove dust while spraying. However, the above patent adopts the traditional water mist dust reduction method, which sprays the dust bounced during spraying to wet the dust reduction. This solution requires a high-pressure water pump, an annular water pipe and multiple spray nozzles. The connection leakage rate of multiple components is high, and it is difficult to ensure that multiple spray nozzles can work normally. In addition, the annular water pipe cannot ensure that the spray volume and pressure of each spray nozzle are consistent, which will result in some areas not being able to achieve the wetting and dust reduction effect.

[0003] How to effectively suppress spraying dust generation, improve the dust reduction effect, improve the working environment of on-site workers, and reduce the adverse effects on the overall construction quality and progress are problems that technical personnel in this field need to solve. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a wet spraying anti-bounce and dust reduction device to solve the problems raised in the above technical background.

[0005] A wet-type spraying device for reducing rebound and dust, comprising a device body, which is a cylinder having a through hole along its axis. The device body forms an inner cavity, which is composed of a medium inlet, a flow guide cavity, an internal confluence cavity, a rectifying cavity, an acceleration cavity, and a medium ring outlet, which are sequentially connected. The through hole is used to accommodate a nozzle for wet concrete spraying.

[0006] There are multiple medium inlets, which are arranged in an annular array on one end face of the device body. The main reason for setting the above-mentioned medium inlet is that after the nozzle of the wet concrete spraying is inserted into the through hole, if the medium inlet is arranged in an annular sleeve form, the feed pipe of the wet concrete spraying nozzle needs to be improved, which increases the technical complexity and cannot make the dust suppression device applicable to other wet concrete spraying nozzles. In addition, the annular medium inlet is difficult to control the consistency of the inflow velocity and pressure on the annular interface. If there is only one medium inlet, since the subsequent internal confluence chamber, rectification chamber, and acceleration chamber are all annular chambers, even if a rectification device is arranged in the middle, it is difficult to adjust the medium flow to have a uniform flow velocity and pressure on the cross section of the acceleration chamber, which easily forms turbulence. Therefore, the present invention provides multiple medium inlets, which are arranged in an annular array on one end face of the device body, and the above-mentioned medium inlets are at the same axial distance from the through hole.

[0007] The number of diversion cavities is the same as the number of medium inlets;

[0008] The side opening of the diversion cavity is connected to the internal confluence cavity;

[0009] The internal confluence cavity, rectification cavity and acceleration cavity are annular cavities;

[0010] The medium ring outlet is annularly opened on the other end surface of the device body.

[0011] Optionally, the medium inlet is inlaid with a steel inner wire ring to connect the medium input pipe.

[0012] Optionally, to reduce energy loss, the diverter bead is hemispherical and integrated into the upper wall of the guide cavity, with the spherical surface facing the medium inlet, and the diameter of the diverter bead is greater than or equal to the diameter of the medium inlet.

[0013] Optionally, the contour line of the cross section of the accelerating cavity adopts a Witoshinsky axis-shift curve, and the preferred curve equation is:

[0014]

[0015]

[0016] Wherein, R0 is half of the width of the dielectric ring outlet (9), preferably 0.25-0.75 mm;

[0017] R h is the axis shift, preferably 0.05R1-0.45R1;

[0018] R1 is half the width of the rectifier cavity (7), preferably 40-50 mm;

[0019] X0 is the axial length of the acceleration chamber (6), preferably 40-50 mm;

[0020] X is the axial length of the self-accelerating chamber entrance, mm;

[0021] R is half of the width of the acceleration chamber (6) at the axial distance X, mm

[0022] N is the shrinkage ratio.

[0023] The purpose of using the Witoshinski axis shift curve is to obtain a suitable and smooth accelerating medium flow.

[0024] Furthermore, a diverter bead is fixed in the flow diversion cavity, and the diameter of the diverter bead is greater than or equal to the diameter of the medium inlet, so that the incoming flow can be evenly distributed to the internal converging cavity and energy consumption is reduced.

[0025] Optionally, the rectifier honeycomb plate is arranged between the internal confluence cavity and the rectifier cavity. Since the inflow into the internal confluence cavity is a convergence of multiple inflows, in order to make the inflow velocity and pressure of the medium entering the acceleration cavity relatively consistent and avoid turbulence,

[0026] Optionally, the radius of the through hole should be greater than or equal to the radius of the concrete wet spraying nozzle, so that the through hole can accommodate the concrete wet spraying nozzle.

[0027] Optionally, a medium is introduced through the medium inlet, sequentially passes through the diversion chamber, internal confluence chamber, rectification chamber, and acceleration chamber, and is ejected from the medium ring outlet to form an annular jet curtain. The medium is a gaseous medium. The high-speed annular jet curtain does not directly wet the dust. Instead, the annular high-speed gas medium compresses and focuses the concrete shotcrete jet, reducing the jet diffusion angle during the wet shotcrete process, thereby increasing the spray thickness and reducing the rebound rate and dust. Furthermore, the dust is isolated within the annular jet curtain, reducing the amount of dust that escapes outward, thus also achieving a dust reduction effect.

[0028] Optionally, the device body is integrally formed by 3D printing, preferably by FDM / SLA / MJF 3D printing, and the printing material is set to black nylon, photosensitive resin, or PETG-CF to ensure the lightness, sealing, and strength of the device body.

[0029] The beneficial effects of the present invention are:

[0030] 1. The medium introduced from multiple medium inlets of the annular array on one end face of the device body enters the internal confluence cavity, and the turbulence intensity of the medium is reduced by the rectifying honeycomb plate and the rectifying cavity, and the flow velocity of the medium is increased by the accelerating cavity. Finally, it is ejected from the medium ring outlet to form a continuous high-speed annular medium curtain, which effectively enhances the convergence of the spray jet, thereby increasing the spray thickness, reducing the rebound rate and spraying loss, and the dust is isolated in the annular jet curtain, and the dust concentration is significantly suppressed.

[0031] 2. The device body is formed in one piece by 3D printing. It has a small size, high integration, good sealing, and is lightweight and high-strength overall. It is installed on the nozzle of the concrete wet spraying machine through a through hole. It is easy to install and has little interference with the existing concrete wet spraying machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the appearance of the wet spraying anti-bounce dust reduction device of the present invention

[0033] Figure 2 It is a cross-sectional schematic diagram of the wet-type spraying anti-bullet dust reduction device of the present invention;

[0034] Figure 3 It is a cross-sectional schematic diagram of the wet-type spraying anti-bounce and dust reduction device of the present invention;

[0035] Figure 4a 、 4b 4c, 4d, and 4e are flow field simulation results of the device according to the embodiment of the present invention;

[0036] Figure 5 This is a diagram showing the experimental results of wet spraying dust reduction using the wet spraying dust reduction device of the present invention at a laboratory scale;

[0037] Figure 6a 、 6b This is a graph showing the test results of the wet spraying dust reduction device of the present invention at a field scale for wet spraying dust reduction.

[0038] Figure 7 This is a comparison chart of the on-site operation effects of the wet spraying anti-bullet dust reduction device of the present invention.

[0039] In the figure: 1-device body; 2-medium inlet; 3-guiding cavity; 4-diverter bead; 5-internal confluence cavity; 6-rectifier honeycomb plate; 7-rectifier cavity; 8-acceleration cavity; 9-medium ring outlet; 10-through hole; L x is the axial distance from the concrete spraying machine nozzle outlet to a certain point, mm; D0 is the concrete spraying machine nozzle diameter, mm. DETAILED DESCRIPTION

[0040] The following describes the embodiments of the present invention through specific examples. It should be noted that the examples described herein are only used to explain the present invention and are not used to limit the present invention. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0041] Example 1

[0042] like Figure 1 、 2As shown, a wet-type spraying dust reduction device according to an embodiment of the present invention includes a device body 1, which is a cylinder having a through hole 10 along its axis. An inner cavity is formed inside the device body 1. The inner cavity is composed of a medium inlet 2, a diversion cavity 3, an internal confluence cavity 5, a rectifying cavity 7, an acceleration cavity 8, and a medium ring outlet 9 connected in sequence.

[0043] The through hole 10 is used to accommodate the nozzle of the wet concrete spraying. The radius of the through hole is set to 55mm so that the dust suppression device can be installed on the nozzle of the wet concrete spraying.

[0044] Four media inlets are arranged in a circular array at the rear of the device body. Each inlet is inlaid with a steel inner wire ring for connection to the media inlet tube. The media inlet radius is set at 20mm. The media inlet and the diversion cavity have the same axial length, which is half the axial length of the internal confluence cavity.

[0045] Each diversion cavity is secured with a hemispherical diverter bead at the top, with the spherical interface facing the media inlet. The diverter bead diameter is equal to or greater than the media inlet diameter to reduce energy consumption. The radius of the diversion cavity is slightly larger than the media inlet radius, set at 25 mm in this embodiment.

[0046] The rectifier honeycomb panel is located between the internal converging chamber and the rectifying chamber. Since the inflow into the internal converging chamber is a convergence of multiple inflows, to ensure that the inflow velocity and pressure of the medium entering the acceleration chamber are relatively consistent and to avoid turbulence, the axial length ratio of the internal converging chamber to the rectifying chamber is 1:2.

[0047] The medium enters from the medium inlet, passes through the guide cavity, internal confluence cavity, rectification cavity, acceleration cavity in sequence, and is ejected from the medium ring outlet to form an annular jet curtain. The medium is a gaseous medium.

[0048] This device needs to form an annular high-speed gas medium at the medium ring outlet 9 to compress and bundle the concrete spraying jet. Therefore, it is necessary to increase the medium flow rate as much as possible and improve the uniformity of the medium flow to avoid turbulence that destroys the bundling of the spraying jet.

[0049] The cross-sectional contour of the accelerating chamber adopts the Witoshinsky axis shift curve to ensure the outlet flow velocity and turbulence. The equation of the curve is:

[0050]

[0051]

[0052] Since the dust suppression device is specifically used in conjunction with a nozzle for wet concrete spraying, the sizes of the medium inlet and outlet, the acceleration chamber and the rectifying chamber must be adapted to the size of the nozzle, wherein R0 is half the width of the medium ring outlet (9), preferably 0.25-0.75 mm;

[0053] R1 is half the width of the rectifier cavity (7), preferably 40-50 mm;

[0054] X0 is the axial length of the acceleration chamber (6), preferably 40-50 mm;

[0055] X is the axial length of the self-accelerating chamber entrance, mm;

[0056] R is half of the width of the acceleration chamber (6) at the axial distance X, mm

[0057] N is the shrinkage ratio.

[0058] If the shift curve is not used, the contraction ratio N is the ratio of R1 to R0, which can reach a maximum of 200. If the contraction ratio is too large, the curve will contract suddenly in the front section and almost not contract in the back section. The sudden contraction of the airflow can easily cause separation and destroy the uniformity of the airflow. Therefore, choose a suitable shift R h The curve is optimized to obtain a high and uniform airflow, with a preferred value of 0.05R1-0.45R1.

[0059] In this embodiment, the flow field of the device using the Witosinski shift curve in the above value range is simulated by Ansys Fluent software to determine the optimal implementation parameters, wherein, when R0 = 0.50 mm, R h =0.05-0.45R1, R1=47.50mm, X0=45mm, when the medium inlet pressure is set to 0.3MPa, Figure 4a 、 4b , 4c, 4d, and 4e.

[0060] At a constant medium inlet pressure (0.3 MPa), the outlet flow rate corresponding to different axis shifts is as follows: Figure 4a When the shift amount is 0.25R1, the contraction ratio N=4.8. At this time, the outlet velocity of the medium ring reaches a peak value of about 47m / s compared with other shift amounts, and the speed inside the device is three-dimensionally rendered. Figure 4b It shows that the speed behind the rectifier cavity is basically uniform. As the airflow inside the device enters the acceleration cavity, Figure 4c The airflow velocity increases gradually until the outlet velocity of the medium ring reaches the maximum, and the airflow is uniform without turbulence. Figure 4d The pressure inside the display device is uniform overall. Figure 4eIt shows that as the internal airflow enters the acceleration chamber, the pressure decreases gradiently until it is completely relieved, and the airflow is uniform without turbulence.

[0061] In this embodiment, the concrete displacement is 5m 3 / h PZ-3 concrete wet spraying machine was used to obtain the relationship between the medium ring outlet velocity and the wet spray flow diffusion angle. In the laboratory scale, by adjusting the different medium inlet pressures, the wet spraying jet diffusion angle change curves under different medium ring outlet flow rates were obtained. Figure 5 , which shows that the medium ring outlet flow rate is negatively correlated with the wet spraying jet diffusion angle. The greater the medium ring outlet flow rate, the smaller the wet spraying jet diffusion angle. When the medium ring outlet flow rate is close to 40m / s, the minimum wet spraying jet diffusion angle is obtained. Therefore, a large medium inlet pressure is selected to obtain the maximum medium ring outlet flow rate.

[0062] It is shown that the device using the above-mentioned implementation parameters can obtain the maximum medium ring outlet flow rate at a constant medium inlet pressure of 0.3 MPa, and the medium flow is uniform and turbulent. It can be mounted on the nozzle of concrete spraying to reduce dust.

[0063] After determining the main implementation parameters of the acceleration chamber, the axial length ratio of the acceleration chamber and the rectifying chamber was set to 3:5, and the parameters of other chambers were also set. The device body was integrated through SLA 3D light-curing printing. The printing material was set to photosensitive resin to prepare a wet spraying anti-bullet dust suppression device.

[0064] Example 2

[0065] This embodiment is a wet spraying dust reduction test using a wet spraying dust reduction device at a field scale. Figure 7 , using CHP25E concrete wet spraying machine, its concrete discharge capacity is 25m 3 / h, the wet spraying bomb reduction and dust reduction device of Example 1 is mounted on the nozzle of a CHP25E concrete wet spraying machine, the nozzle diameter is 50 mm, and the sprayed concrete strength is C30.

[0066] Figure 7 It can visually display the on-site operation effect of the wet spraying dust reduction device. Figure 7 The left picture shows the on-site operation of the wet concrete spraying machine without the wet spraying dust reduction device installed on the nozzle. It can be seen that the concrete slurry is sprayed out from the nozzle in a diffused manner, forming a large amount of dust that fills the working space. Figure 7 The picture on the right shows the on-site operation of a wet spraying machine with a wet spraying dust reduction device installed on the nozzle. The concrete slurry is sprayed out from the nozzle in a roughly columnar shape, and the concrete spraying jet is well bundled within the high-speed annular medium curtain, significantly reducing the amount of dust in the working space.

[0067] The effect of jet diffusion angle contraction during wet spraying is as follows Figure 6a The results show that under a medium inlet pressure of 0.3 MPa, the average effective shrinkage rate of the wet spraying jet diffusion angle before and after the wet spraying dust reduction device of Example 1 is 35.7%, and the maximum effective shrinkage rate is 56%, indicating that the wet spraying dust reduction device has a good shrinkage effect on the jet diffusion angle during the wet spraying process.

[0068] Comparison of dust concentration suppression effect during wet spraying Figure 6b The results show that under the medium inlet pressure of 0.3MPa, the average effective suppression rate before and after the wet spraying dust reduction device is used is 57.9%, and the maximum effective suppression rate is 87.6%. The maximum dust concentration of the overall wet spraying has never exceeded 80.41mg / m 3 , which is basically at the trough value when the wet spraying dust reduction device is not used, indicating that the wet spraying dust reduction device has an excellent effect in suppressing dust generation during the wet spraying process.

[0069] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A wet spraying anti-bounce and dust reduction device, characterized in that: The device comprises a device body (1), the device body (1) is a cylinder having a through hole (10) along the axis, an inner cavity is formed inside the device body (1), and the inner cavity is composed of a medium inlet (2), a flow guide cavity (3), an internal confluence cavity (5), a rectifying cavity (7), an acceleration cavity (8) and a medium ring outlet (9) which are connected in sequence; the through hole (10) is used to accommodate a nozzle for wet concrete spraying; There are a plurality of medium inlets (2) which are arranged in a ring array on one end surface of the device body (1); The number of the flow guide cavities (3) is the same as the number of the medium inlets (2); The side opening of the flow guiding cavity (3) is connected to the internal flow converging cavity (5); The internal converging chamber (5), the rectifying chamber (7) and the accelerating chamber (8) are annular chambers; The medium ring outlet (9) is annularly disposed on the other end surface of the device body (1).

2. A wet spraying anti-bounce and dust reduction device according to claim 1, characterized in that: The contour line of the cross section of the acceleration chamber (6) adopts the Witoshinsky axis-shift curve, and the curve equation is: Where R0 is half the width of the dielectric ring outlet (9), mm; R h is the axis shift, mm; R1 is half the width of the rectifying cavity (7), mm; R is half the width of the accelerating cavity (6) at the axial distance X, mm; X0 is the axial length of the accelerating cavity (6), mm; X is the axial length from the entrance of the accelerating cavity, mm; and N is the contraction ratio.

3. A wet spraying anti-bounce and dust reduction device according to claim 1 or 2, characterized in that: A flow diversion bead (3) is fixed in the flow diversion cavity (2), and the diameter of the flow diversion bead (3) is greater than or equal to the diameter of the medium inlet (1).

4. A wet spraying anti-bounce and dust reduction device according to claim 1 or 2, characterized in that: The rectifying honeycomb plate (6) is arranged between the internal confluence cavity (5) and the rectifying cavity (7).

5. A wet spraying anti-bounce and dust reduction device according to claim 1 or 2, characterized in that: The medium inlet (1) is inlaid with a steel inner wire ring.

6. According to claim 1, a wet spraying anti-bounce and dust reduction device is characterized in that: The axial lengths of the rectifying cavity (7) and the accelerating cavity (8) are 5:

3.

7. A wet spraying anti-bounce and dust reduction device according to claim 1 or 2, characterized in that: The medium is introduced from the medium inlet (1), passes through the guide cavity (3), the internal converging cavity (5), the rectifying cavity (7), and the accelerating cavity (8) in sequence, and is ejected from the medium ring outlet (7) to form an annular jet curtain. The medium is a gaseous medium.

8. The wet spraying anti-bounce and dust reduction device according to claim 1, characterized in that: The device body (1) is integrally formed by 3D printing.

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