Self-cleaning pulse injection dust remover for hot-rolled stainless steel band

Abstract

The invention relates to the technical field of industrial flue gas purification, and discloses a self-cleaning pulse injection dust remover for hot rolling of stainless steel bands, which comprises a dust remover box body, a filter unit is arranged in the box body, an air bag is fixedly mounted on one side of the box body, and a lower hopper is fixedly connected to the bottom of the box body. The filter is characterized by further comprising a self-rotating fire-retarding and ash-removing assembly arranged on the air inlet side of the filter unit; the self-rotating fire-retarding and ash-cleaning assembly comprises a spiral flow-guiding type fire arrester capable of rotating around the axis of the spiral flow-guiding type fire arrester. According to the invention, through the self-rotating fire-retarding and ash-cleaning assembly which is arranged on the air inlet side of the filter unit and is provided with the spiral arc blade, sparks in high-temperature flue gas can be effectively blocked, cooled and extinguished in the labyrinth channel; meanwhile, most of high-hardness and high-abrasiveness coarse particles with the particle size larger than 50 microns are separated in advance under the action of strong centrifugal force and fall into an ash hopper, so that the mechanical abrasion load of a follow-up filter bag is obviously reduced from the source, and the service life of the filter bag is prolonged.

Description

Technical Field

[0001] This invention relates to the field of industrial flue gas purification technology, specifically a self-cleaning pulse jet dust collector for hot-rolled stainless steel strip. Background Technology

[0002] In the production of hot-rolled stainless steel strip, furnaces such as heating furnaces and annealing furnaces generate high-temperature flue gas containing a large amount of high-hardness, irregularly shaped, and abrasive metal oxide dust, such as chromium oxide and nickel oxide. Currently, the mainstream technology in this field is to purify the flue gas using pulse-jet bag filters. Pulse cleaning utilizes the instantaneous release of compressed air to cause the filter bags to expand and vibrate, thereby removing dust. The filter media often uses high-temperature resistant membrane filter cartridges or bags to cope with the flue gas temperature and improve the cleaning effect. This technological system forms the foundation of flue gas treatment in this industry.

[0003] However, existing technologies still exhibit significant shortcomings when dealing with the special flue gas from hot-rolled stainless steel. First, high-hardness, angular dust, especially coarse particles larger than 50μm, can still enter the dust collector body, continuously cutting and abrading the filter bag fibers like micro-sandpaper, leading to a significant reduction in filter bag lifespan. Second, oil mist, water vapor, and fine dust in the flue gas combine to easily form a dense and robust caking layer on the filter bag surface. The instantaneous airflow impact of traditional pulse cleaning has limited effectiveness in peeling off such firmly adhered caking layers. Existing technologies cannot specifically remove the most abrasive particles from the filter bags. Moreover, pulse cleaning, as a powerful intervention method after caking has formed, has a single mechanism of action and cannot effectively intervene or prevent caking in its early stages. Summary of the Invention

[0004] In view of the shortcomings of existing self-cleaning pulse jet dust collectors mentioned in the background art, the present invention provides a self-cleaning pulse jet dust collector for hot-rolled stainless steel strip, which has the advantages of flame arrest, pre-dust removal and anti-caking dust removal, and solves the technical problems mentioned in the background art.

[0005] This invention provides the following technical solution: a self-cleaning pulse jet dust collector for hot-rolled stainless steel strip, comprising a dust collector housing, a filter unit disposed inside the housing, an air manifold fixedly installed on one side of the housing, and a lower hopper fixedly connected to the bottom of the housing, characterized in that: it further comprises a self-rotating flame arrestor and cleaning assembly disposed on the air inlet side of the filter unit; the self-rotating flame arrestor and cleaning assembly comprises a spiral flow guide flame arrester rotatable around its own axis, and at least one flexible scraper disposed on the spiral flow guide flame arrester; the rotation axis of the spiral flow guide flame arrester is parallel to or coincident with the axis of the filter unit, so that the flexible scraper can be close to the surface of the filter unit; the spiral flow guide flame arrester is provided with a spiral arc surface in its circumference, which is used to generate a rotational torque under the action of flue gas flow, driving the self-rotating flame arrestor and cleaning assembly to rotate as a whole.

[0006] Preferably, the spiral flow-guiding flame arrester has a cylindrical structure, with multiple spiral arc blades extending axially on its outer circumferential surface, and a labyrinthine channel for flue gas passage is formed between adjacent spiral arc blades.

[0007] Preferably, the helix angle of the helical arc blade is 45° to 60°.

[0008] Preferably, the flexible scraper is made of a high-temperature resistant elastic material and is fixed to the spiral flow-guiding flame arrester by a connecting arm.

[0009] Preferably, the connecting arm is provided with an elastic pre-tightening mechanism for adjusting the contact pressure between the flexible scraper and the surface of the filter unit.

[0010] Preferably, the filtration unit includes multiple filter bags, the self-rotating flame-retardant cleaning component is sleeved on the outside of the filter bag group, and the end of the flexible scraper maintains elastic contact with the outer surface of the filter bag.

[0011] Preferably, a fixed spark arrester for blocking large particles of molten slag is provided upstream of the spiral flow-guiding flame arrester.

[0012] Preferably, the system also includes a control system, which includes a differential pressure sensor for monitoring the inlet and outlet pressure difference of the filter unit. When the differential pressure exceeds a preset threshold, the control system can adjust the flow rate of flue gas entering the dust collector housing or start an auxiliary drive device to change the rotation speed of the self-rotating flame arrestor cleaning assembly.

[0013] Preferably, the auxiliary drive device is a low-speed motor, and its output shaft is connected to the rotating shaft of the spiral flow guide flame arrester via a clutch.

[0014] The present invention has the following beneficial effects: 1. This invention utilizes a self-rotating flame-arresting and ash-removing assembly with spiral arc blades installed on the air inlet side of the filter unit. This assembly effectively blocks and cools and extinguishes sparks in the high-temperature flue gas within a labyrinthine channel. Simultaneously, it pre-separates most of the high-hardness, highly abrasive coarse particles with a diameter greater than 50μm under strong centrifugal force, causing them to fall into the ash hopper. This significantly reduces the mechanical wear load on subsequent filter bags from the source, extending their service life.

[0015] 2. This invention utilizes the tangential thrust generated by the flue gas flow on the spiral arc blades to drive the flame-arresting dust removal assembly to rotate continuously. This causes the flexible scraper on the assembly to continuously and gently scrape the surface of the filter bag, which can physically destroy and peel off the dust caking layer that is forming on the outer wall of the filter bag in the initial stage. This, together with pulse jet cleaning, forms a synergistic mechanism of continuous mechanical intervention and periodic powerful dust removal, effectively solving the problem of traditional single pulse cleaning being ineffective in removing sticky caking layers.

[0016] 3. The present invention monitors the pressure difference of the filter unit in real time through an optional intelligent control system, and automatically adjusts the flue gas flow or starts the auxiliary drive device to change the rotation speed of the rotating component when the pressure difference rises abnormally. This enables the entire cleaning process to have adaptive and enhanced intervention capabilities, ensuring that a stable and efficient cleaning effect can still be maintained under low load or abnormal caking conditions, thereby improving the reliability and intelligence level of the system in dealing with complex working conditions. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the internal structure of the present invention; Figure 2 This is a vertical sectional view of the overall structure of the present invention; Figure 3 This is a cross-sectional view of the present invention. Figure 4 This is a schematic diagram of the overall structure of the self-rotating flame arrestor and ash removal assembly of the present invention; Figure 5 This is a schematic diagram of the internal structure of the spiral flow-guiding flame arrester of the present invention.

[0018] In the diagram: 1. Housing; 11. Air chamber; 12. Lower hopper; 2. Filter unit; 21. Filter bag; 3. Self-rotating flame arrestor and dust removal assembly; 31. Spiral flow guide flame arrestor; 311. Spiral arc blade; 32. Flexible scraper. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] This invention is particularly suitable for treating high-temperature flue gas generated by industrial furnaces such as heating furnaces, reheating furnaces, and annealing furnaces in the hot rolling process of steel. The high hardness and irregular dust contained in the flue gas can easily lead to filter bag wear and caking.

[0021] First embodiment: Please see Figures 1 to 5 This embodiment describes a basic implementation method in detail.

[0022] This embodiment provides a self-cleaning dust removal device for high-temperature flue gas, specifically designed for flue gas purification in furnaces or stoves. This self-cleaning pulse jet dust collector includes a vertical dust collector housing 1 welded from steel plates. The interior of the housing 1 is divided into an upper clean air chamber and a lower dust chamber by a perforated plate. In the dust chamber, multiple filter bags 21 constituting a filtration unit 2 are arranged in a dense and orderly array along the vertical direction. The filter bags 21 are preferably made of glass fiber needle-punched felt with an ePTFE membrane coating. This membrane filter material can withstand temperatures above 200°C for extended periods, and its smooth membrane surface achieves true surface filtration, ensuring that most dust remains on the membrane surface rather than embedded within the fibers, thus providing a physical basis for efficient dust removal. On one side of the housing 1, an air tank 11 storing compressed air is fixedly installed. The air tank 11 is connected via pipelines to pulse valves arranged in the clean air chamber. The pulse valves' jet pipes are aligned with the upper openings of each row of filter bags 21, forming a complete pulse jet cleaning system. The bottom of the box 1 is a cone-shaped or trough-shaped lower hopper 12, which is used to collect the dust that has been removed. Its inner wall is smooth and the inclination angle is greater than 70°. A dust discharge valve is provided at the bottom.

[0023] like Figure 4 and Figure 5 As shown, the main body of the spiral flow-guiding flame arrester 31 is a cylindrical frame. Multiple spiral arc blades 311 are uniformly fixed axially on its circumferential surface. These blades extend continuously at a constant spiral angle; in this preferred embodiment, this angle is designed to be 45° to 60°, thus forming a labyrinthine channel with a specific inclination angle encircling the cylindrical wall between adjacent blades. The spiral arc blades 311 are preferably made of heat-resistant steel plates, and together they constitute a robust cage structure. This structure has three functions: firstly, the tortuous labyrinthine channel effectively blocks and cools any sparks that may be entrained in the flue gas, preventing them from directly impacting the filter bag; secondly, when the flue gas flows through these spiral channels at a certain velocity, it exerts a continuous force on the inclined surface of the blades; and thirdly, the guiding effect of the channel generates a strong rotational centrifugal force in the flow of the flue gas.

[0024] The spiral flow-guiding flame arrester 31 is supported in a high-temperature resistant sealed bearing seat mounted on the internal frame of the housing 1 via a rotating shaft at its upper and lower ends. This allows the spiral flow-guiding flame arrester 31 to rotate freely around its central axis. When flue gas flows through the spiral arc blades 311, the force exerted by the airflow on the inclined surface of the blades can be decomposed into axial and tangential components. The tangential components acting on all blades combine into a continuous rotational torque. Therefore, as long as the flue gas continues to flow, this torque will drive the entire spiral flow-guiding flame arrester 31 to rotate spontaneously and uniformly, with its rotational speed approximately proportional to the flue gas flow rate, thus achieving power source derived from the operating conditions and adapting to the flue gas flow rate.

[0025] To achieve physical dust removal, at least one flexible scraper 32 is fixedly installed on the cylinder of the spiral flow-guiding flame arrester 31 via a radially extending connecting arm. The flexible scraper 32 is made of a high-temperature resistant, highly elastic, and wear-resistant material; in this embodiment, a silicone rubber plate with a long-term operating temperature exceeding 200°C is used. Its free end is designed to maintain a gentle, elastic contact with the outer surface of the outermost ring of filter bags 21. To ensure uniform and stable contact pressure and avoid excessive pressure causing wear or insufficient pressure causing ineffectiveness due to installation errors or thermal deformation, an elastic pre-tightening mechanism is provided on the connecting arm. This mechanism can be a simple spring plate assembly or an adjustable pre-pressure elastic clamp, which can automatically compensate for minor deviations and maintain a constant, gentle scraping force.

[0026] To address the potential for large-sized hot iron oxide scale or molten slag to be ejected directly from the hot rolling furnace, a fixed spark arrester is installed upstream of the spiral flow-guiding flame arrester 31, at the inlet where the flue gas enters the housing. This arrester is typically a multi-layered, staggered arrangement of heat-resistant steel gratings or perforated plates, serving as the first line of coarse protection to intercept large particles of slag and reduce the workload of the core components.

[0027] The method of using (working principle) of this invention is as follows: The high-temperature, dust-laden flue gas discharged from the hot rolling furnace first enters the inlet of the dust collector housing 1. The flue gas first impacts the fixed spark arrestor, where larger, hot particles are directly intercepted and cooled. Subsequently, the flue gas enters the area of ​​the self-rotating flame arrestor cleaning assembly 3. The flue gas is forced to flow along the labyrinthine channel formed by the spiral arc blades 311. During this process: a) Remaining small sparks frequently collide with the cold metal blades in the tortuous channel, and the heat is rapidly absorbed and extinguished. b) The flue gas rotates within the spiral channel, where larger, especially harder, coarse particles with a diameter greater than 50μm, such as chromium oxide particles, are thrown towards the outer wall of the channel under strong centrifugal force and slide down the wall, eventually falling directly into the lower hopper 12. This effectively separates the coarse particles that cause the most severe wear on the filter bags before they contact the filter bags, significantly reducing the wear load on the filter bags at the source. c) Simultaneously, the thrust of the flue gas continuously acts on the blades, driving the entire self-rotating flame arrestor cleaning assembly 3 to rotate smoothly.

[0028] As the spiral flow-guiding flame arrester 31 rotates, the flexible scraper 32 fixed on it moves in a circular motion. The flexible scraper 32 gently and continuously scrapes the outer surface of the filter bag 21. This continuous, low-intensity mechanical intervention can effectively disrupt the initial structure of the dust layer as it begins to clump, preventing it from developing into a hard crust. Even if slight clumps form, they can be loosened in time. Due to the flexible contact, the scraping process does not damage the fibers or membrane of the filter bag itself. After the above pretreatment, the dust concentration and particle hardness of the flue gas have been significantly reduced, and it then passes evenly through the filter bag 21 for final fine filtration. When the control system triggers pulse cleaning, compressed air in the air tank 11 is instantly injected into the interior of the filter bag through the pulse valve, causing it to expand violently and shake off the dust. Since the surface dust layer has been kept loose by the rotating scraper, this pulse cleaning becomes exceptionally efficient and thorough. The removed dust falls into the lower hopper 12 and is discharged periodically. The cleaning intensity of the entire system is adaptive. When the rolling mill output is high and the flue gas flow rate is high, the rotation speed of the self-rotating flame arrestor and dust removal component 3 will naturally increase and the scraping frequency will increase to cope with the higher dust load; when the flow rate decreases, the rotation speed will slow down to achieve energy-saving operation.

[0029] Second embodiment: Building upon the first implementation method, this implementation method adds an intelligent control system to further improve the dust removal guarantee rate under abnormal operating conditions. This system includes a differential pressure sensor mounted on the housing 1, used to monitor the inlet and outlet pressure difference of the filter unit 2 in real time. The differential pressure signal is transmitted to the PLC controller. When the differential pressure sensor detects that the pressure difference continuously exceeds a preset threshold, indicating that filter bag caking may worsen, the PLC can trigger an action and issue a command.

[0030] The instructions enhance the cleaning intensity of the self-rotating flame arrestor cleaning assembly 3 in two ways: Firstly, the regulating valve on the main flue is adjusted to moderately increase the flow rate of flue gas entering the dust collector for a short period of time. The increase in flow rate will directly lead to a passive increase in the rotation speed of the self-rotating flame-arresting cleaning component 3, thereby increasing the scraping frequency and force in a short period of time, impacting the slab layer.

[0031] Secondly, such as Figure 2 As shown, an auxiliary drive device is connected to the end of the rotating shaft of the spiral flow-guiding flame arrester 31. The auxiliary drive device is a low-speed explosion-proof motor with a clutch. Under normal circumstances, the clutch is disengaged, and the self-rotating flame arrester and cleaning assembly 3 rotates freely by airflow. When a reinforced cleaning command that can be grasped by the PLC is received, the clutch engages, the motor starts, and provides an active and stable additional speed for the self-rotating flame arrester and cleaning assembly 3, ensuring effective forced cleaning even under low load conditions. After cleaning is completed, the motor stops, the clutch disengages, and the system returns to pure pneumatic drive mode.

[0032] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0033] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A self-cleaning pulse jet dust collector for hot-rolled stainless steel strip, comprising a dust collector housing (1), wherein a filter unit (2) is provided inside the housing (1), an air manifold (11) is fixedly installed on one side of the housing (1), and a lower hopper (12) is fixedly connected to the bottom of the housing (1), characterized in that: It also includes a self-rotating flame arrestor and soot removal assembly (3) disposed on the air inlet side of the filter unit (2); the self-rotating flame arrestor and soot removal assembly (3) includes a spiral flow guide flame arrester (31) that can rotate around its own axis, and at least one flexible scraper (32) disposed on the spiral flow guide flame arrester (31); the rotation axis of the spiral flow guide flame arrester (31) is parallel or coincident with the axis of the filter unit (2), so that the flexible scraper (32) can be close to the surface of the filter unit (2); the spiral flow guide flame arrester (31) is provided with a spiral arc surface in the circumference, which is used to generate a rotational torque under the action of flue gas flow, driving the self-rotating flame arrestor and soot removal assembly (3) to rotate as a whole.

2. The self-cleaning pulse jet dust collector for hot-rolled stainless steel strip according to claim 1, characterized in that: The spiral flow-guiding flame arrester (31) has a cylindrical structure, and its outer circumferential surface is provided with multiple spiral arc blades (311) extending axially. Adjacent spiral arc blades (311) form a labyrinthine channel for the passage of flue gas.

3. The self-cleaning pulse jet dust collector for hot-rolled stainless steel strip according to claim 2, characterized in that: The helix angle of the helical arc blade (311) is 45° to 60°.

4. The self-cleaning pulse jet dust collector for hot-rolled stainless steel strip according to claim 1, characterized in that: The flexible scraper (32) is made of high-temperature resistant elastic material and is fixed to the spiral flow guide flame arrester (31) by a connecting arm.

5. A self-cleaning pulse jet dust collector for hot-rolled stainless steel strip according to claim 4, characterized in that: The connecting arm (321) is provided with an elastic pre-tightening mechanism for adjusting the contact pressure between the flexible scraper (32) and the surface of the filter unit (2).

6. A self-cleaning pulse jet dust collector for hot-rolled stainless steel strip according to claim 1, characterized in that: The filter unit (2) includes multiple filter bags (21), the self-rotating flame-retardant cleaning component (3) is sleeved on the outside of the filter bag (21) group, and the end of the flexible scraper (32) maintains elastic contact with the outer surface of the filter bag (21).

7. A self-cleaning pulse jet dust collector for hot-rolled stainless steel strip according to claim 6, characterized in that: A fixed spark arrester for blocking large particles of molten slag is provided upstream of the spiral flow-guiding flame arrester (31).

8. A self-cleaning pulse jet dust collector for hot-rolled stainless steel strip according to any one of claims 1-7, characterized in that: It also includes a control system, which includes a differential pressure sensor for monitoring the inlet and outlet differential pressure of the filter unit (2). When the differential pressure exceeds a preset threshold, the control system can adjust the flow rate of flue gas entering the dust collector housing (1) or start an auxiliary drive device to change the rotation speed of the self-rotating flame arrestor cleaning assembly (3).

9. A self-cleaning pulse jet dust collector for hot-rolled stainless steel strip according to claim 8, characterized in that: The auxiliary drive device is a low-speed motor, whose output shaft is connected to the rotating shaft of the spiral flow guide flame arrester (31) via a clutch.

Images