Negative pressure air flow screen and material screening device

Abstract

The negative pressure airflow screen and material screening device comprises a shell, a screen, material enters from a feeding port at the upper part of the shell and falls on the screen, a wind knife assembly and a motor are arranged below the screen, the wind knife assembly comprises a plurality of wind knives, the air outlets of the wind knives face the screen, and the motor drives the wind knives to rotate horizontally, the material is sucked by negative pressure during screening, the material falling on the screen is blown upward by the wind knives, the material is blown up and then falls on the screen again, and material agglomeration can be effectively avoided.

Description

Technical Field

[0001] This invention relates to industrial material screening equipment, specifically a negative pressure airflow screen and material screening device. Background Technology

[0002] Negative pressure airflow sieving instruments are mainly used for screening materials to facilitate particle size analysis. Because some powdery / particle materials are prone to agglomeration under the influence of static electricity and other factors, lumps entering subsequent processes can affect the technical efficiency. Existing negative pressure airflow sieves include mechanisms for blowing and flotating materials, which can solve the agglomeration problem to some extent; however, they are mainly used for laboratory screening, and their small size and limited capacity result in low screening efficiency in production activities, making them unsuitable for large-scale automated production.

[0003] Patent publication CN214975748U discloses a negative pressure airflow screen, comprising a body with an open upper end and an internal cavity. A feeding tray has a feeding port and an air blowing mechanism. A screen is located on the upper end of the feeding tray. The negative pressure mechanism includes a vacuum fan located within the body cavity, and the material recovery mechanism includes a separator located outside the body. One end of the vacuum fan is connected to the upper end of the separator via a pipe, and the other end is connected to an air outlet on the side wall of the body. One side of the separator is connected to the feeding port via a pipe. This design uses negative pressure to absorb material while simultaneously blowing it onto the screen, preventing material agglomeration and facilitating rapid and accurate screening. However, the blade rotation is passive, resulting in slow speed and low efficiency, making it unsuitable for large-scale industrial production. Summary of the Invention

[0004] To address the existing problems, this invention aims to provide a negative pressure airflow screen and material screening device that can be integrated into an industrial production line for large-scale production.

[0005] To achieve the above objectives, the technical solution adopted by the present invention includes a shell and a screen. The material enters from the feed port at the top of the shell and falls onto the screen. An air knife assembly and a motor are provided below the screen. The air knife assembly includes several air knives, and the air outlets of the air knives face the screen. The motor drives the air knives to rotate horizontally.

[0006] In some embodiments, the air knife assembly includes an air intake pipe that connects an external air source to the inner cavity of the air knife in the air knife assembly.

[0007] In some embodiments, the outer end of the air intake pipe passes through and is fixed to the side wall of the housing, forming an air inlet; the outer wall of the air intake pipe is sealed to the housing; its inner end is fixedly connected to the inner housing and connected to the inner cavity of the ventilation knife; external air (normal atmospheric pressure) is drawn in under negative pressure, enters the inner housing through the air intake pipe, and continues to be delivered to the air outlet of the ventilation knife under negative pressure.

[0008] In some embodiments, the motor is located in the inner housing, and the motor drives the air knife to rotate horizontally circumferentially via a connecting shaft.

[0009] In some embodiments, the motor is a pneumatic motor or an electric motor.

[0010] In some embodiments, there are at least two intake pipes, or the intake pipes are arranged horizontally.

[0011] In some embodiments, the roots of several air blades are fixedly connected to a rotating shaft, and a motor drives the rotating shaft to rotate.

[0012] In some embodiments, the blade of the air knife extends radially.

[0013] In some embodiments, the air knife assembly includes four air knives, and the opening position and length of the air outlet of each air knife (blade) are evenly distributed along the diameter direction of rotation.

[0014] In some embodiments, the air blowing area of ​​one revolution of the air knife is greater than or equal to the area of ​​the filter screen.

[0015] In some embodiments, the distance between the air knife and the screen is less than 80 mm.

[0016] In some embodiments, the screen is horizontally arranged, or the screen is circular, or the screen diameter is 600 mm.

[0017] In some embodiments, the air outlet area of ​​the air knife is equivalent to the area of ​​the air inlet on the housing or the air inlet duct.

[0018] In some embodiments, the housing includes an upper housing and a lower housing, which are detachably connected by a plurality of bolts.

[0019] In some embodiments, the top of the upper housing is provided with a feed inlet, and / or the upper housing is also provided with another discharge outlet.

[0020] In some embodiments, the lower housing is conical, or the bottom of the cone of the lower housing is provided with a discharge port, or the discharge port is provided with a valve.

[0021] In some embodiments, the outer wall of the housing is provided with connectors for securing it to a steel frame.

[0022] In operation, the vacuum feeder with storage function transports materials to the storage system through pressure difference. The storage system then transports the materials to the air classifier through pipelines. The materials enter the interior of the negative pressure air classifier through the feed inlet, fall onto the screen, and the screen vibrates. At the same time, the air knife operates, and the materials are screened. The screened materials fall into the lower shell and are discharged from the machine through the discharge port. Large particles that are not screened are discharged from the machine through another discharge port.

[0023] The present invention also provides a material screening device, including any of the aforementioned negative pressure airflow screens, vacuum feeders, and two sets of cyclone separators and dust collectors; wherein, the vacuum feeder is connected to the inlet of the negative pressure airflow screen, and the outlet of the negative pressure airflow screen and another outlet are respectively connected to the two sets of cyclone separators and dust collectors.

[0024] In some embodiments, the system further includes a plurality of negative pressure fans, which are respectively connected to a vacuum feeder and two sets of dust collectors.

[0025] Compared with existing technologies, this invention uses negative pressure to absorb and screen materials while using air knives to blow the materials falling onto the screen upwards. After being blown up, the materials fall back onto the screen, which can effectively prevent material agglomeration. The air knives are driven by a motor to rotate actively in a circumferential direction. The blowing operation can cover the entire screen without affecting the downward movement of the materials. The high speed and efficiency are conducive to the rapid and accurate screening of materials. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the negative pressure airflow screen.

[0027] Figure 2 This is a three-dimensional view of the negative pressure airflow screen;

[0028] Figure 3 This is a cross-sectional view of the air knife assembly;

[0029] Figure 4 A 3D view of the air knife assembly and motor;

[0030] Figure 5 This is a top view of the air knife assembly;

[0031] Figure 6 This is a schematic diagram of a material screening device.

[0032] Referring to the attached diagram, the components are: air knife assembly 1, air knife 101, air outlet 102, air inlet pipe 103, air inlet 104, pneumatic motor 105, rotating shaft 106, and connecting shaft 107.

[0033] 2. Screen, 3. Inlet, 4. Outlet, 5. Upper shell, 6. Lower shell. Detailed Implementation

[0034] The present invention will now be further described with reference to the accompanying drawings.

[0035] See Figures 1 to 3 , Figures 1 to 3 This illustration shows an embodiment of the present invention, a "Type 600" negative pressure airflow screen. This embodiment mainly includes a housing, a screen, an air knife assembly, and a motor. The housing is fully enclosed except for the inlet and outlet ports. The screen is located in the upper part of the housing, the air knife is located below the screen, and the motor is connected to the air knife.

[0036] Among them, see Figure 2 The housing consists of an upper housing and a lower housing, which are detachably connected by a series of bolts along their circumference. A feed inlet is located at the center of the top of the upper housing, and this inlet is connected to a vacuum feeder.

[0037] See Figure 2 The lower shell is conical, with a discharge port at the bottom of the cone for connecting to the first set of air separators; the upper shell is also provided with another discharge port for connecting to the second set of air separators.

[0038] Preferably, a valve is provided at the discharge port; on the outer wall of the lower shell, connectors for fixing to the steel frame are evenly provided along the circumference.

[0039] See Figure 1 and Figure 3 The air knife assembly includes several air knives; in this embodiment, there are four air knives. The root of each air knife is fixedly connected to the side wall of the rotating shaft. The motor drives the rotating shaft and the air knives to rotate horizontally via the connecting shaft. The blade of each air knife is elongated and extends horizontally radially.

[0040] The preferred air knife has its outlet opening position and length evenly distributed along the diameter of rotation, forming a long, narrow air outlet band. Further, see... Figure 5 Each air knife has its outlet staggered along the diameter direction, and the ring-shaped air belts formed by each of them when rotating together constitute a complete circular air outlet surface.

[0041] The shaft is hollow inside, with its lower end connected to an air source and its circumferential side connected to the inner cavity of the ventilation knife. The shaft is fixedly connected to the motor's connecting shaft. During operation, the housing is drawn in by an external negative pressure fan. The air pressure inside the housing is lower than the external atmospheric pressure, so the gas is drawn in through the inlet pipe, transported and supplied to the air outlet through the shaft, and then blown upwards towards the screen from the outlet, thus buoying the material.

[0042] See Figure 1 , Figure 3 and Figure 4 The air knife assembly includes two hollow air intake pipes, which are preferably horizontally arranged. The outer end of the air intake pipe penetrates and is fixed to the side wall of the housing, forming an air inlet; and the outer wall of the air intake pipe is sealed to the housing. The inner end of the air intake pipe is fixedly connected to the side wall of the inner housing; external air enters the inner housing and the interior of the rotating shaft through the air intake pipe, and is drawn out by negative pressure and then delivered to the air outlet of the air knife.

[0043] While connecting to the air source, the air intake pipe also serves as a support structure to fix the motor and air knife inside the housing. Furthermore, the motor (preferably a pneumatic motor, but an electric motor can also be used) is also located in the inner housing (lower half). The motor drives the rotating shaft to rotate through the upward-extending connecting shaft, which in turn drives the air knife to rotate horizontally in the same direction.

[0044] See Figure 1 In this embodiment, during use, the material enters the interior through the feed inlet at the top of the shell and falls onto the screen due to the combined effects of gravity and negative pressure. The screen vibrates using an ultrasonic generator to sieve the material. Simultaneously, the air knife assembly operates, with the air knife rotating horizontally circumferentially driven by a motor. The air outlet of the air knife blows air upwards, buoying the material upwards. Because the air knife rotates horizontally, the combined effect with the buoyancy blowing creates a blowing area during one rotation. The material in this blowing area, after floating, falls back onto the screen by gravity, avoiding agglomeration. The material passing through the screen then falls into the lower shell and is finally discharged from the machine through the discharge port. Larger particles that are not sieved are discharged from the shell through another discharge port.

[0045] Furthermore, the distance between the air knife and the screen is preferably less than 80mm. The screen is generally horizontally positioned and circular. In this embodiment, the screen diameter is 600mm, but other sizes can be selected as needed.

[0046] See Figure 6 The present invention also provides a material screening device, including any of the negative pressure airflow screens and vacuum feeders in the foregoing embodiments, as well as two sets of cyclone separators, dust collectors, and a material collection bin. The vacuum feeder is connected to the inlet of the negative pressure airflow screen, and the outlet and another outlet of the negative pressure airflow screen are respectively connected to the two sets of cyclone separators and dust collectors. The vacuum feeder, cyclone separators, and dust collectors are all existing equipment.

[0047] Furthermore, it also includes several negative pressure fans, which are respectively connected to a vacuum feeder and two sets of dust collectors.

[0048] When the machine is needed, press the control button, and the vacuum feeder will suck the material into the storage device built into the vacuum feeder. After the vacuum feeder has finished storing the material, the discharge valve will open, and the material will enter the negative pressure airflow screen through the pipeline, and the negative pressure airflow screen will start working.

[0049] The material falls onto the screen by gravity, the screen vibrates to screen the material, and the air knife below rotates to blow up the material accumulated on the screen. The material blown by the air falls back onto the screen by gravity, and the material that has passed through the screen falls into the shell below the air classifier.

[0050] After a certain amount is stored, the valve below the lower shell opens, and the material is transported through a pipeline to the cyclone separator collector. Most of the material will remain here, while a small portion of the material that is lifted will be sucked into the dust collector. The material stored in the cyclone separator collector and the dust collector can enter the receiving bucket through the discharge valve. Some large particles that cannot pass through the screen can enter the No. 2 cyclone separator through the discharge port above the air classifier. Most of the material will remain here, while a small portion of the material that is lifted will be sucked into the No. 2 dust collector.

[0051] The embodiments of the present invention have been described above with reference to the accompanying drawings and examples. The structures given in the embodiments do not constitute a limitation of the present invention. Those skilled in the art can make adjustments as needed, and various modifications or variations within the scope of the appended claims are all within the scope of protection.

Claims

1. A negative pressure air flow screen comprising a housing, a screen, material entering the housing from a feed inlet and falling onto the screen, characterised in that: The housing consists of an upper housing and a lower housing, with the lower housing being conical. An air knife assembly and a motor are located below the screen, with the motor housed within the inner housing. The air knife assembly includes several air knives with their air outlets facing the screen. The air outlets of the air knives are staggered along the diameter direction, and when they rotate, they form annular air bands, which in turn constitute a complete circular air outlet surface. The air knife assembly includes an air intake pipe, which serves as a support structure to fix the motor and air knife inside the housing. The outer end of the air intake pipe passes through and is fixed to the side wall of the housing, forming an air inlet. Its inner end is fixedly connected to the inner housing and to the inner cavity of the air knife. External air is subjected to negative pressure and enters the inner housing through the air intake pipe, and is then transported by negative pressure to the air outlet of the air knife. The motor drives the air knife to rotate horizontally.

2. The negative pressure air stream curtain according to claim 1, characterized in that: The motor drives the air knife to rotate horizontally in a circumferential direction via a connecting shaft.

3. The negative pressure air stream curtain of claim 1, wherein: There are at least two intake pipes; and / or the intake pipes are horizontally arranged.

4. A negative pressure air stream curtain according to any one of claims 1-3, characterized in that: The roots of several air knives are fixedly connected to a rotating shaft, which is driven to rotate by a motor; and / or the blades of the air knives extend radially.

5. The negative pressure air stream curtain of claim 4, wherein: The air knife assembly includes four air knives, the opening position and length of the air outlet of each air knife are evenly distributed along the diameter of rotation; and / or the air blowing area of ​​one rotation of the air knife is greater than or equal to the area of ​​the filter screen.

6. The negative pressure air stream curtain of claim 4, wherein: The distance between the air knife and the screen is less than 80mm; and / or the screen is horizontally set; and / or the screen is circular; and / or the diameter of the screen is 600mm.

7. The negative pressure air stream curtain of claim 4, wherein: The air outlet area of ​​the air knife is roughly the same as the air inlet area on the housing or the air inlet pipe.

8. The negative pressure air stream curtain of claim 1, wherein: The upper and lower housings are detachably connected by several bolts.

9. The negative pressure air stream curtain of claim 8, wherein: The upper shell has a feed inlet at the top and another discharge outlet; the lower shell has a discharge outlet at the bottom of its conical shape.

10. The negative pressure air stream curtain of claim 8, wherein: The outer wall of the housing is provided with connectors for fixing it to the steel frame.

11. A material screening apparatus characterized by: It includes the negative pressure airflow screen and vacuum feeder as described in claim 9, as well as two sets of cyclone separators and dust collectors; wherein, the vacuum feeder is connected to the inlet of the negative pressure airflow screen, and the outlet and another outlet of the negative pressure airflow screen are respectively connected to the two sets of cyclone separators and dust collectors.

12. The material screening apparatus of claim 11, wherein: It also includes several negative pressure fans, which are connected to a vacuum feeder and two sets of dust collectors respectively.

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