A negative pressure collection device

Abstract

The utility model relates to a kind of negative pressure collecting devices, including box, dust suction pipe and exhaust pipe are equipped on box, cyclone dust removal assembly is further arranged in box inside, wherein the end of dust suction pipe towards outside is connected with the end part of wind diffuser cover, the end of dust suction pipe towards inside is mutually communicated with the air inlet end of cyclone dust removal assembly, exhaust pipe is set to the top of box and is mutually communicated with the air outlet end of cyclone dust removal assembly, the lower portion of box is further equipped with ash valve, dust suppression spraying assembly is further equipped on the side of the top of box, air pump is further equipped on exhaust pipe;The application uses multistage separator to match auxiliary spraying unit and dust suppression unit, to work cooperatively, not only can utilize double spraying design from "source pre-control + end purification" whole process to inhibit dust diffusion, completely solve the secondary dust problem of existing equipment, can form extremely thin water film on sand surface using dry mist spraying, subsequent through cyclone dust removal assembly can be easily separated.

Description

Technical Field

[0001] This utility model relates to the field of resin sand recycling technology, specifically to a negative pressure collection device. Background Technology

[0002] In the foundry industry, resin sand is widely used in the production and processing of various castings due to its advantages such as high strength, good collapsibility, excellent surface quality of castings, high production efficiency, and reduced resource waste. However, resin sand casting processes generate a large amount of waste resin sand after casting. Directly discarding this waste resin sand not only occupies significant land resources and causes serious solid waste pollution, but also wastes recyclable quartz sand resources, increasing the company's raw material procurement costs. Therefore, efficient recycling of waste resin sand to achieve sand reuse has become a crucial step for foundry companies to reduce costs, increase efficiency, and practice green production principles.

[0003] Existing resin sand recovery equipment still suffers from numerous problems in practical applications due to technical design flaws, making it difficult to meet the needs of foundry enterprises for efficient and high-quality resin sand recovery. These problems are specifically reflected in the following aspects: 1. Severe dust pollution and lack of effective dust suppression measures. During resin sand recycling, crushing, screening, and conveying processes generate large amounts of dust. This dust contains not only quartz sand particles but also residual resin volatiles. If not effectively controlled, it will seriously harm the respiratory system of workshop operators and pollute the surrounding atmosphere. On the one hand, dust is easily re-entrained by airflow turbulence before entering the dust collection device, increasing the difficulty of dust removal. On the other hand, in low-temperature environments, some equipment using spray dust suppression is prone to water freezing, causing the dust suppression system to fail and unable to continuously exert its dust suppression effect, exacerbating the dust pollution problem. 2. Low level of automation, unable to achieve precise control and status monitoring. Existing resin sand recycling equipment often uses independent fixed parameter control for each working unit (such as crushing, screening, and dust removal units), lacking a coordinated linkage mechanism. When the composition, moisture content, and agglomeration degree of the waste resin sand change, the equipment cannot automatically adjust the operating parameters of each unit (such as crushing speed, screening frequency, dust removal air volume, and spraying volume) according to the actual working conditions. This leads to either a decrease in the quality of the recycled sand due to parameter mismatch or increased production costs due to excessive energy consumption. In summary, existing resin sand recovery equipment has significant shortcomings in terms of recovery efficiency, sand cleanliness, dust control, level of intelligence, and structural stability, making it difficult to meet the current casting industry's demand for green, efficient, and high-quality resin sand recovery. Therefore, developing a resin sand recovery device with high recovery efficiency, good sand cleanliness, excellent dust suppression, high level of intelligence, and stable operation has become a crucial technical problem urgently needing to be solved by those skilled in the art, and is of great significance for promoting the green and sustainable development of the casting industry. Utility Model Content

[0004] Based on the above description, this utility model provides a negative pressure collection device to solve the shortcomings of existing resin sand recycling equipment, which lack effective dust suppression measures and have obvious deficiencies in terms of recycling efficiency, sand cleanliness, dust control, intelligent level and structural stability.

[0005] This utility model is achieved through the following technical solution: A negative pressure collection device includes a housing with a suction pipe and an exhaust pipe. A cyclone dust collector assembly is also arranged inside the housing. The outer end of the suction pipe is connected to an air diffuser, and the inner end of the suction pipe is connected to the air inlet of the cyclone dust collector assembly. The exhaust pipe is located at the top of the housing and is connected to the exhaust end of the cyclone dust collector assembly. A dust discharge valve is located at the bottom of the housing and is positioned at the dust discharge port at the bottom of the cyclone dust collector assembly. A dust suppression spray assembly is also located on one side of the top of the housing, extending downwards and simultaneously connected to both the suction pipe and the exhaust pipe. An air pump is also installed on the exhaust pipe.

[0006] Based on the above technical solution, the present invention can be further improved as follows.

[0007] Furthermore, the cyclone dust removal assembly includes a first separator and a second separator. Both the first separator and the second separator are cone-shaped and interconnected by an air guide pipe. The inward-facing end of the suction pipe extends tangentially into the interior of the first separator and is interconnected with it. One end of the air guide pipe is vertically inserted into the top of the first separator and is interconnected with it. The other end of the air guide pipe extends to the side wall of the second separator and is tangentially connected to the interior of the second separator. The inward-facing end of the exhaust pipe is vertically inserted into the top of the second separator and extends into the interior of the second separator.

[0008] Furthermore, the dust suppression spray assembly includes an auxiliary spray unit and a dust suppression unit, wherein the auxiliary spray unit consists of multiple nozzles arranged around the outer wall of the suction pipe, and each nozzle is connected to the suction pipe; the dust suppression unit includes a dust settling chamber arranged on one side of the housing, wherein a mesh-structured spray pipe is horizontally arranged in the dust settling chamber, and the exhaust pipe is connected to the dust settling chamber.

[0009] Furthermore, each group of three nozzles is provided with a connecting seat, which is bolted to the surface of the suction pipe. The surface of the connecting seat is also provided with a connecting groove, and multiple nozzles are correspondingly inserted into the connecting groove and communicate with each other through the suction pipe. The angle between the nozzle axis and the airflow direction is ≤30°.

[0010] Furthermore, the suction pipe is also equipped with a venturi tube, which is located downstream of the auxiliary spray unit.

[0011] Furthermore, both the spray unit and the dust suppression unit are connected to the same water pump via water supply pipes, and electric regulating valves are also installed on the two water supply pipes.

[0012] Furthermore, dust content sensors are respectively installed on the air guide pipe and the exhaust pipe, and the dust content sensors and the electric regulating valve are all remotely connected to the same controller.

[0013] Furthermore, an electric heater is also provided on the water supply pipe located on the auxiliary spray unit.

[0014] Compared with the prior art, the technical solution of this application has the following beneficial technical effects: 1. This application improves upon existing negative pressure recovery equipment for resin sand. This application adopts a multi-stage separator combined with an auxiliary spray unit and a dust suppression unit to work together. It can not only use the dual spray design to suppress dust diffusion from the source pre-control + end purification process, completely solving the problem of secondary dust generation in existing equipment, but also use the spray structure of the auxiliary spray unit to form an extremely thin water film on the surface of the sand particles by using dry mist spraying. The residual resin is not easy to soften and stick, and can be easily separated by the cyclone dust removal component. The residual resin removal rate is increased by more than 20%. 2. In addition, the controller can receive dust concentration data from the dust concentration sensor in real time. When the dust concentration in the air duct is too high, it automatically increases the opening of the electric regulating valve of the auxiliary spray unit to increase the pre-spray volume. When the dust concentration in the exhaust pipe exceeds the standard, it automatically increases the opening of the electric regulating valve of the dust suppression unit to enhance exhaust gas purification. Compared with the existing fixed parameter operation mode, water consumption is reduced by 20%-30%, while ensuring that the dust treatment effect always meets the standard, avoiding energy and resource waste. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the housing and dust suppression spray assembly in this embodiment; Figure 2 This is a schematic diagram of the structure of the housing and auxiliary spray unit in this embodiment; Figure 3 This is a schematic diagram of the cyclone dust removal component in this embodiment; Figure 4 This is a schematic diagram of the structure of the first separator in this embodiment; Figure 5 This is a schematic diagram of the internal structure of the dust settling chamber in this embodiment; The components include: 1. Housing; 11. Suction pipe; 12. Exhaust pipe; 13. Venturi tube; 2. Cyclone dust removal assembly; 21. First separator; 22. Second separator; 23. Air guide pipe; 3. Dust suppression spray assembly; 31. Auxiliary spray unit; 311. Connecting seat; 312. Spray head; 32. Dust suppression unit; 321. Dust settling chamber; 322. Spray pipe; 33. Electric heater; 34. Water supply pipe. Detailed Implementation

[0016] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0018] Combination Figure 1-5 As shown, a negative pressure collection device includes: Box 1 is the main structure of the entire negative pressure collection device. It is hollow inside and has a dust suction pipe 11 and an exhaust pipe 12 on the outer side wall. The exhaust pipe 12 is also equipped with an air pump, i.e. a negative pressure pump, which achieves the purpose of negative pressure dust collection by suction. Cyclone dust collector assembly 2 includes a first separator 21 and a second separator 22, both of which are located inside the housing 1 and are interconnected for graded recycling. The dust suppression spray assembly 3 includes an auxiliary spray unit 31 and a dust suppression unit 32. The auxiliary spray unit 31 is for "dust source pretreatment", while the dust suppression unit 32 is for "deep purification of exhaust gas". The two work together to achieve the purpose of dust control throughout the entire process.

[0019] Specifically, in this embodiment, both the first separator 21 and the second separator 22 are configured as conical structures, and the top of the first separator 21 and the sidewall of the second separator 22 are connected to each other by an air guide pipe 23.

[0020] The dust generated during resin sand recycling varies considerably in particle size, including large resin clumps and coarse impurities (mostly ≥50μm) from waste sand, as well as fine dust and residual resin particles (mostly ≤20μm) adhering to the surface of the sand grains. Single-stage cyclone separators, limited by the single intensity of the centrifugal force field, struggle to efficiently capture both types of dust simultaneously. If the focus is on separating coarse particles, fine dust easily escapes with the airflow; conversely, if the capture of fine dust is emphasized, coarse particles tend to accumulate and clog the separator.

[0021] Therefore, the two work together to form a combined structure of "coarse separation stage" + "fine separation stage": First separator 21 (coarse separation stage): Air is drawn in tangentially through suction pipe 11, creating a strong centrifugal force field using high tangential air velocity to preferentially separate coarse particulate impurities with a particle size ≥20μm and resin clumps. These substances move rapidly towards the inner wall of the separator under centrifugal force, eventually settling along the wall to the bottom ash discharge port, where they are discharged through the ash discharge valve, preventing them from entering subsequent stages and causing equipment wear or blockage. Second separator 22 (fine separation stage): The airflow (containing a large amount of fine dust ≤20μm) that has been preliminarily purified by the first separator 21 enters the second separator 22 tangentially through the air guide pipe 23. The structural parameters of the second separator 22 (such as cone angle and cylinder diameter) have been optimized to form a centrifugal force field suitable for fine dust separation—although the airflow velocity is slightly lower than that of the first separator 21, the centrifugal force acts for a longer time, which can accurately capture fine dust and cause it to settle and separate.

[0022] Through this graded design, the total dust removal efficiency of the two-stage cyclone recovery structure can reach over 95%, which is 15-20 percentage points higher than that of a single-stage structure (dust removal efficiency is usually ≤80%). The fine dust removal rate is also significantly improved (from about 60% in a single stage to over 90%), ensuring that the dust content in the exhaust gas and the dust residue in the recovered sand both meet industry standards.

[0023] In addition, the coarse particles separated by the first separator 21 are discharged directly through the ash discharge valve, preventing them from entering the downstream air duct 23, the second separator 22 and the dust suppression unit 32, thus reducing the impact and wear on the pipes and equipment components. The second separator 22 further removes fine dust, significantly reducing the dust content of the airflow entering the dust suppression unit 32, reducing the adhesion of fine dust in the spray pipe 322 and the exhaust pipe 12, reducing the frequency of sensor cleaning and maintenance, and extending the service life of the spray pipe 322.

[0024] The auxiliary spray unit 31 consists of multiple nozzles 312 arranged around the outer wall of the suction pipe 11, in groups of three, and is further fixed by connecting seats 311. The angle between the nozzle axis of each nozzle 312 and the airflow direction is ≤30°. The multiple connecting seats 311 are bolted to the suction pipe 11 (if multiple connecting seats 311 are used, a distance of 80-100cm should be maintained between every two connecting seats 311). The nozzles 312 should be ultrasonic atomizing nozzles 312, which, through the surrounding arrangement, precisely spray micron-level dry mist into the suction pipe 11, mainly to achieve two functions: 1. Dust pre-wetting and aggregation: For the high-speed flow of waste resin sand and dust mixture in the suction pipe 11, the dry mist sprayed by the nozzle 312 can quickly collide and adsorb with the dust particles, causing the fine dust (particle size ≤20μm) to aggregate into a denser "dust-droplet" aggregate, avoiding dust flying with the airflow in the pipe, reducing the secondary dust formed by dust adhering to the pipe wall, and reducing the processing load of the subsequent cyclone dust removal component 2; 2. Precise control of sand moisture content: By controlling the water spray volume and droplet size (10-50μm) of the nozzle 312, the sand moisture content is strictly controlled within the safe range of 0.5%-1%. This avoids the sand from becoming too wet and clumping due to excessive water volume in traditional spraying (affecting crushing and screening efficiency), and also prevents the sand from becoming too dry and causing dust diffusion. At the same time, it protects the original physical structure of the sand particles (such as angularity and strength).

[0025] Moreover, in this structure, the low-water-volume dry fog forms an extremely thin water film only on the surface of the sand particles, preventing the sand particles from softening and wearing due to excessive wetting. The integrity of the sand particle shape is maintained at over 90%, and the residual resin is not easy to stick together due to excessive moisture. Subsequent separation is more convenient, and the recycled sand can directly meet the requirements of precision casting for sand quality.

[0026] In addition, a Venturi tube 13 is provided on the suction pipe 11. The Venturi tube 13 is arranged downstream of the auxiliary spray unit 31. Its airflow regulation function works synergistically with the "dry fog dust suppression" of the auxiliary spray unit 31 to further improve the dust pretreatment effect: ① Accelerate airflow to enhance the probability of droplet-dust collision: The dry fog (10-50μm) sprayed by the auxiliary spray unit 31 needs to fully collide with the dust particles to form a "dust-droplet" aggregate. The airflow acceleration effect of the converging section of Venturi tube 13 can increase the relative velocity of the dust-laden airflow and dry fog by 30%-40%, significantly increasing the collision frequency of droplets and dust. Especially for fine dust with small particle size (≤20μm), the aggregation efficiency is increased by more than 25%, reducing the amount of fine dust that escapes with the airflow. ② The deceleration of the expansion section extends the mixing time: the airflow velocity decreases after entering the expansion section, allowing the "dust-droplet" aggregate more time (0.5-1 second longer than without Venturi tube 13) to form stably. This avoids the aggregate breaking due to excessive airflow speed, ensuring that the pre-treated dust can be separated more efficiently by the subsequent cyclone dust removal component 2, reducing the processing load of the two-stage cyclone separator.

[0027] The synergistic effect of "spray dust suppression + venturi tube 13 airflow regulation" increases the fine dust capture rate of the auxiliary spray unit 31 from 85% to over 92%, providing key support for the cyclone dust removal component 2 to achieve "95% total dust removal efficiency".

[0028] Considering the impact of external temperature on the spray structure in actual working scenarios, an electric heater 33 should also be equipped on the water supply pipe 34 of the spray unit, so that it can heat and keep the spray water warm in a low temperature environment of -10℃ to 0℃, prevent the mist droplets from freezing and clogging the nozzles 312 or causing dust suppression failure, and enable the equipment to operate stably in cold northern regions and low-temperature workshops.

[0029] The dust suppression unit 32 focuses on "deep purification of exhaust gas at the end of the process." By setting up an independent dust settling chamber 321 and a mesh-structured spray pipe 322, it performs secondary spraying on the exhaust gas after it has been treated by the two-stage cyclone dust removal components 2, mainly achieving two core functions: 1. Residual dust removal in exhaust gas: For the trace amounts of fine dust (particle size ≤10μm, easily escaped with airflow) remaining in the exhaust gas after cyclone dust removal, the horizontally arranged mesh spray pipes 322 in the dust settling chamber 321 can form a uniform "water film barrier". When the exhaust gas passes through the water film, the residual dust is further intercepted and adsorbed, ensuring that the dust content of the final exhaust gas is ≤10mg / m³, which meets the requirements of the national "Integrated Emission Standard of Air Pollutants" (GB 16297-1996); 2. Exhaust gas cooling and humidity regulation: During the resin sand recycling process, the airflow temperature will rise slightly after crushing and cyclone separation (usually 5-10℃ higher than the ambient temperature). The spray water of the dust suppression unit 32 can cool the exhaust gas and regulate its humidity at the same time to avoid secondary dust generation after the dry exhaust gas is discharged, and further optimize the workshop working environment.

[0030] In addition, the dust suppression unit 32 shares the same water pump with the auxiliary spray unit 31 through the water supply pipe 34, and electric regulating valves are respectively installed on the two water supply pipes 34. At the same time, dust content sensors are correspondingly installed on the exhaust pipe 12 and the dust suction pipe 11. In addition, a controller (Siemens S7-200 SMART CPU ST40) is arranged to make the electric regulating valve, the dust content sensor and the controller work together. When the sensor detects that the dust content in the exhaust gas exceeds the standard, the controller automatically increases the opening of the electric regulating valve to increase the spray volume; when the dust content meets the standard, the spray volume is reduced. Compared with the fixed spray mode, water consumption is reduced by 20%-30%, achieving a balance between energy saving and environmental protection.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of this utility model.

Claims

1. A negative pressure collection device, characterized in that, The box includes a housing (1), on which a suction pipe (11) and an exhaust pipe (12) are provided. A cyclone dust removal assembly (2) is also arranged inside the housing (1). The end of the suction pipe (11) facing outward is connected to an air diffuser. The end of the suction pipe (11) facing inward is connected to the air inlet of the cyclone dust removal assembly (2). The exhaust pipe (12) is located at the top of the housing (1) and is connected to the exhaust end of the cyclone dust removal assembly (2). A dust discharge valve is also provided below the housing (1). The dust discharge valve is located at the dust discharge port at the bottom of the cyclone dust removal assembly (2). A dust suppression spray assembly (3) is also provided on one side of the top of the housing (1). The dust suppression spray assembly (3) extends downward and is connected to both the suction pipe (11) and the exhaust pipe (12). An air pump is also provided on the exhaust pipe (12).

2. The negative pressure collection device according to claim 1, characterized in that, The cyclone dust removal assembly (2) includes a first separator (21) and a second separator (22). The first separator (21) and the second separator (22) are both cone-shaped and connected to each other through an air guide pipe (23). The inward end of the suction pipe (11) extends tangentially into the interior of the first separator (21) and is connected to each other. One end of the air guide pipe (23) is vertically inserted into the top of the first separator (21) and is connected to each other. The other end of the air guide pipe (23) extends to the side wall of the second separator (22) and is tangentially connected to the interior of the second separator (22). The inward end of the exhaust pipe (12) is vertically inserted into the top of the second separator (22) and extends into the interior of the second separator (22).

3. The negative pressure collection device according to claim 2, characterized in that, The dust suppression spray assembly (3) includes an auxiliary spray unit (31) and a dust suppression unit (32). The auxiliary spray unit (31) consists of multiple nozzles (312) arranged around the outer wall of the suction pipe (11), and each nozzle (312) is connected to the suction pipe (11). The dust suppression unit (32) includes a dust settling chamber (321) arranged on one side of the housing (1). A mesh structure spray pipe (322) is horizontally arranged in the dust settling chamber (321), and the exhaust pipe (12) is connected to the dust settling chamber (321).

4. The negative pressure collection device according to claim 3, characterized in that, Each group of three nozzles (312) is provided with a connecting seat (311). The connecting seat (311) is bolted to the surface of the suction pipe (11), and the surface of the connecting seat (311) is also provided with a connecting groove. Multiple nozzles (312) are correspondingly inserted into the connecting groove and communicate with each other with the suction pipe (11). The nozzle axis of the nozzle (312) has an angle ≤30° with the airflow direction.

5. The negative pressure collection device according to claim 4, characterized in that, The suction pipe (11) is also provided with a venturi tube (13), which is located downstream of the auxiliary spray unit (31).

6. The negative pressure collection device according to claim 5, characterized in that, The spray unit and the dust suppression unit (32) are both connected to the same water pump through water pipes (34), and electric regulating valves are also provided on the two water pipes (34).

7. The negative pressure collection device according to claim 6, characterized in that, The air duct (23) and the exhaust pipe (12) are respectively equipped with dust content sensors, and the dust content sensors and the electric regulating valve are remotely connected to the same controller.

8. The negative pressure collection device according to claim 7, characterized in that, An electric heater (33) is also provided on the water supply pipe (34) located on the auxiliary spray unit (31).

Images