Constant-air-volume mining hydraulic dust remover and control method

Abstract

The invention belongs to the technical field of coal mine dust prevention, and relates to a constant-air-volume mining hydraulic dust remover and a control method. The dust remover comprises a dust removal section, a dehydration section, a fan section and a noise elimination section which are sequentially arranged, the fan section comprises a fan impeller and a constant displacement hydraulic motor, and the hydraulic motor drives the fan impeller to rotate and is connected with a hydraulic system. The hydraulic system comprises an LS feedback oil way, a load-sensitive variable pump, an oil tank, a liquid suction filter, a motor, a safety valve, a main oil way filter and a throttling valve which are connected to form a circulating oil way. The motor drives the variable pump to suck oil from the oil tank through the liquid suction filter, and the variable pump outputs pressure oil to drive the hydraulic motor through the main oil way filter and the throttle valve. According to the dust remover, the front-back pressure difference of the throttling valve is kept constant, so that the flow is only related to the through-flow area and is not related to the load pressure change, and the problem that the air volume is reduced due to the rising of the system resistance in the using process of an existing dust remover is solved.

Description

Technical Field

[0001] This invention belongs to the field of coal mine dust control technology, and relates to a constant air volume mine hydraulic dust collector and its control method. Background Technology

[0002] Dust is one of the major natural hazards in underground mines. During coal mining and tunneling operations, large amounts of dust are generated, permeating the working environment and posing a significant threat to human health. With the widespread use of large-scale mining equipment such as roadheaders and tunneling-anchoring machines, the amount of dust generated in mines is increasing, making dust control work more challenging and difficult.

[0003] In underground coal mine working faces, wet-type electric dust collectors are mainly used for dust control. These dust collectors use a fan to draw dust-laden airflow into the device for purification. A typical dust collector includes a fan, spray frame, filter, dewatering device, and silencer. The air volume handled by the dust collector is usually designed to be 0.8 to 1 times the air volume supplied to the roadway to ensure sufficient dust extraction and purification capacity; the rated power of the fan is selected accordingly. The fan uses an explosion-proof three-phase asynchronous motor as its power source. The characteristic of this type of motor is that its speed decreases with increasing load. In actual use, as the resistance of the dust collector's inlet pipe changes, and as issues such as filter blockage and adhesion to the dewatering device occur, the system resistance of the dust collector gradually increases. At this point, the fan needs to output greater torque to maintain its original speed. To output greater torque, the motor's slip increases, leading to a decrease in the motor's actual speed, thus reducing the fan's airflow. The filter screen is typically cleaned daily, and the dehydrator is cleaned monthly. Therefore, during dust collector operation, as resistance continuously increases, the suction air volume decreases. This directly leads to a decline in dust suppression capacity, resulting in poorer dust control in the tunnels. To restore the designed air volume, the fan must increase its power to overcome the increased resistance. However, since the fan's rated power is selected based on the designed air volume, the power of the fan at the work site cannot be arbitrarily increased, and the dust collector's air volume cannot meet the design requirements. If a high-power motor with redundancy is used as the power source, a frequency converter must be installed for speed regulation. However, the space in coal mines is cramped, high-power motors are larger, and additional frequency converters are required, making practical installation difficult and impractical. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to solve the above problems and provide a constant air volume hydraulic dust collector for mining and a control method. Through hydraulic drive and control, when the resistance of the dust collector system increases and the speed decreases, the output pressure of the hydraulic pump is automatically increased, thereby driving the fan impeller to overcome greater resistance, maintaining the speed constant, and keeping the processing air volume of the dust collector constant.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A constant airflow mine hydraulic dust collector includes a dust removal section, a dehydration section, a fan section, and a silencer section arranged sequentially. The fan section includes a fan impeller and a fixed-displacement hydraulic motor, which drives the fan impeller to rotate. A hydraulic system is connected to the fixed-displacement hydraulic motor. The hydraulic system includes an LS feedback oil circuit forming a circulating oil circuit, a load-sensitive variable pump, an oil tank, a suction filter, a motor, a main oil circuit filter, and a throttle valve. The motor drives the load-sensitive variable pump to draw oil from the oil tank through the suction filter. The output pressure oil from the variable pump drives the hydraulic motor through the main oil circuit filter and the throttle valve. The LS feedback oil circuit is connected downstream of the throttle valve to the LS control port of the variable pump, maintaining a constant pressure difference between the pump outlet pressure and the load pressure at 1~2MPa to ensure constant flow rate and constant fan impeller speed.

[0006] Furthermore, the hydraulic system maintains a constant pressure difference ΔP across the throttle valve, ensuring that the flow rate Q through the throttle valve is only related to the fixed flow area A of the throttle valve and is independent of changes in load pressure. The flow rate calculation formula is as follows:

[0007] Where C is the flow coefficient and ρ is the hydraulic oil density.

[0008] Furthermore, the LS feedback oil circuit senses the downstream load pressure in real time and connects to the control port of the variable pump to achieve automatic pressure compensation; the load-sensitive variable pump automatically adjusts the swashplate angle and changes the displacement based on the pressure of the LS feedback oil circuit and the pressure difference set by the internal spring.

[0009] Furthermore, the hydraulic system also includes a safety valve connected to the outlet of the load-sensitive variable pump to protect the system from overpressure damage.

[0010] Furthermore, the dust removal section includes a spray frame and a filter screen. The spray frame is equipped with a spiral nozzle located upstream of the filter screen, 100-150mm away from the filter screen, and the spray field covers the surface of the filter screen.

[0011] Furthermore, the filter screen adopts a multi-layer metal mesh combination, including at least one layer of 4-mesh metal mesh as the skeleton, located on the outermost layer, providing structural support; at least 4 to 6 layers of 50-mesh metal mesh are located in the inner layer, which play a filtering role.

[0012] Furthermore, the dewatering section adopts a corrugated plate structure, connecting the dust removal section outlet and the fan section inlet, with the bottom drain outlet discharging the dust-water mixture.

[0013] Furthermore, the dehydration air velocity in the dehydration section is 5~7m / s.

[0014] Furthermore, the filter screen of the dust removal section is arranged at an angle of 50 to 80 degrees with the horizontal and is inclined along the air inlet direction.

[0015] A control method for a constant air volume mine hydraulic dust collector as described above uses a load-sensitive variable pump to drive a fixed-displacement hydraulic motor. The downstream load pressure is sensed in real time through the LS feedback oil circuit. The variable pump automatically adjusts its displacement according to the feedback pressure and the set pressure difference to maintain a constant pressure difference of 1~2MPa between the pump outlet pressure and the load pressure, ensuring a constant flow through the throttle valve, thereby maintaining a constant hydraulic motor speed and a constant fan impeller speed.

[0016] Furthermore, when the resistance of the dust collector system increases, the load pressure rises, and the variable pump automatically increases the output pressure to compensate for the pressure difference change and maintain a constant flow rate.

[0017] Furthermore, the set differential pressure is achieved through an internal spring in the variable pump, and the flow rate calculation formula for the hydraulic system is as follows:

[0018] Where Q is the flow rate; C is the flow coefficient, which is related to the orifice type; and A is the flow area. It is the pressure difference before and after the throttling orifice; ρ is the liquid density; The constant pressure difference means that the flow rate depends only on the flow area of ​​the throttle valve and is independent of load changes.

[0019] Furthermore, the LS feedback oil circuit is connected downstream of the throttle valve to the LS control port of the variable pump, providing real-time load pressure feedback to achieve automatic adjustment.

[0020] Furthermore, the electric motor drives the variable pump to draw oil from the oil tank, which is then filtered by the suction filter and output as pressurized oil. This pressurized oil is then supplied to the hydraulic motor through the main oil circuit filter and the throttle valve.

[0021] Furthermore, a safety valve is connected to the outlet of the variable pump, which overflows when the system pressure is too high, protecting the hydraulic system from damage.

[0022] Furthermore, the control method is applied to dust collectors in coal mine working faces. When the filter screen is clogged or the dewatering section is stuck, causing the resistance to increase, the fan impeller speed is automatically maintained constant.

[0023] Furthermore, the variable displacement pump changes its displacement by adjusting the swashplate angle, thus responding to load changes and ensuring stable dust removal capacity.

[0024] The beneficial effects of this invention are as follows: This invention employs a load-sensitive pump control system to drive the dust collector fan. This system uses an LS feedback oil circuit to sense the downstream load pressure in real time and automatically adjusts the displacement of the variable pump to maintain a constant pressure difference between the pump outlet pressure and the load pressure, thereby ensuring a constant flow rate through the throttle valve. This keeps the fan impeller speed constant, as well as the airflow and dust collection capacity constant, maintaining stable and efficient dust removal. It effectively solves the problem of decreased airflow due to increased resistance in existing dust collectors during operation. In the high-dust environment of underground coal mines, this constant airflow characteristic ensures continuous dust collection capacity, significantly reducing dust concentration in roadways, improving the working environment for workers, and reducing the risk of occupational diseases such as pneumoconiosis.

[0025] Furthermore, the hydraulic motor, as a power source, is significantly smaller than an explosion-proof motor of equivalent power, typically less than a quarter of its size. This helps reduce the overall volume of the dust collector. In the confined spaces of underground coal mine working faces, the reduced equipment size means easier installation and layout, expanding the dust collector's applicability. For example, in space-constrained areas near roadheaders or tunneling and anchoring machines, the compact design of the hydraulic motor allows for more flexible integration of the dust collector into existing equipment systems without occupying excessive space. This not only improves the equipment's portability and adaptability but also reduces the difficulty of transportation and maintenance, further enhancing the overall efficiency of coal mine production.

[0026] This invention employs a pure hydraulic control method, featuring a simple structure, high reliability, and avoiding complex electrical explosion-proof issues. Key components of the hydraulic system, such as the load-sensitive variable pump, throttle valve, and LS feedback oil circuit, achieve automatic adjustment through mechanical and hydraulic principles, eliminating the need for additional electronic controllers or frequency converters, thus reducing potential failure points. In the humid and dusty underground environment, the hydraulic system's sealing and durability are superior to electrical systems, avoiding safety hazards caused by electrical sparks. Furthermore, the system's simplicity simplifies maintenance; operators only need to periodically inspect the oil circuits and filters to maintain long-term stable operation, reducing operating costs for coal mining enterprises.

[0027] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0028] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 This is a schematic diagram of a constant air volume hydraulic dust collector for mining and its control method.

[0029] Figure 2 This is a schematic diagram of a hydraulic system.

[0030] Attached reference numerals: 1-Dust removal section; 11-Spray frame; 12-Filter screen; 2-Dehydration section; 3-Fan section; 31-Fan impeller; 32-Hydraulic motor; 4-Silencing section; 5-Hydraulic system; 51-LS feedback oil circuit; 52-Load-sensitive variable pump; 53-Oil tank; 54-Suction filter; 55-Motor; 56-Safety valve; 57-Main oil circuit filter; 58-Throttle valve. Detailed Implementation

[0031] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0032] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0033] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0034] Example 1 like Figures 1-2As shown, a constant airflow mine hydraulic dust collector includes a dust removal section 1, a dehydration section 2, a fan section 3, and a silencer section 4 arranged sequentially. The fan section 3 includes a fan impeller 31 and a fixed-displacement hydraulic motor 32, which drives the fan impeller 31 to rotate. A hydraulic system 5 is connected to the fixed-displacement hydraulic motor 32. The hydraulic system 5 includes an LS feedback oil circuit 51 that forms a circulating oil circuit, a load-sensitive variable pump 52, an oil tank 53, a suction filter 54, a motor 55, a safety valve 56, a main oil circuit filter 57, and a throttle valve 58. The motor 55 drives the load-sensitive variable pump 52 to draw oil from the oil tank 53 through the suction filter 54. The variable pump 52 outputs pressurized oil that drives the hydraulic motor 32 through the main oil circuit filter 57 and the throttle valve 58. The LS feedback oil circuit 51 connects downstream of the throttle valve 58 to the LS control port of the variable pump 52, maintaining a constant pressure difference between the pump outlet pressure and the load pressure at 1~2MPa to ensure constant flow and constant rotation speed of the fan impeller 31.

[0035] The dust removal section 1 includes a spray frame 11 and a filter screen 12. The spray frame 11 is equipped with a spiral nozzle, which is located upstream of the filter screen 12 and 100-150mm away from the filter screen 12. The spray field covers the surface of the filter screen 12. The filter screen 12 is composed of multiple layers of metal mesh, including at least one layer of 4-mesh metal mesh as the skeleton, located on the outermost layer to provide structural support; at least 4-6 layers of 50-mesh metal mesh are located in the inner layer to perform the filtering function; the filter screen 12 is arranged at an angle of 50-80° with the horizontal and is inclined along the air inlet direction.

[0036] The dehydration section 2 adopts a corrugated plate structure, connecting the outlet of the dust removal section 1 and the inlet of the fan section 3. The bottom drain outlet discharges the dust-water mixture; the dehydration wind speed of the dehydration section 2 is 5-7m / s.

[0037] When used in underground coal mine working faces, the dust-laden airflow enters from the inlet of dust removal section 1, is moistened by the spray frame 11, and then passes through the filter screen 12 to capture dust. It then enters the dehydration section 2 to separate moisture, and the fan section 3 provides suction power. The clean airflow is discharged from the silencer section 4. When the resistance of the dust collector system increases, the load pressure rises. The LS feedback oil circuit 51 senses the downstream load pressure in real time. The variable pump 52 automatically adjusts the swashplate angle according to the feedback pressure and the pressure difference set by the internal spring, changing the displacement, increasing the output pressure, compensating for pressure difference changes, maintaining a constant flow rate, and ensuring that the hydraulic motor 32 and the fan impeller 31 operate at constant speeds. The flow rate calculation formula for the hydraulic system is:

[0038] Where Q is the flow rate; C is the flow coefficient, which is related to the type of throttle orifice; A is the flow area; ΔP is the pressure difference before and after the throttle orifice; ρ is the liquid density; the constant pressure difference ΔP ensures that the flow rate is only related to the flow area of ​​the throttle valve 58 and is independent of load changes; the safety valve 56 is connected to the outlet of the variable pump 52 and overflows when the system pressure is too high, protecting the hydraulic system 5 from damage; the entire process does not require an additional electronic controller and achieves automatic adjustment only through hydraulic principles, which is convenient for stable operation in the humid and dusty environment downhole.

[0039] Example 2 This embodiment is a control method for the constant air volume mine hydraulic dust collector based on Embodiment 1. The control method specifically includes the following steps: When the dust collector is started at the underground mining face of a coal mine, the electric motor 55 first drives the load-sensitive variable pump 52 to draw oil from the oil tank 53 through the suction filter 54. The pressure oil output by the variable pump 52 passes through the main oil circuit filter 57 and the throttle valve 58 in sequence and is then supplied to the quantitative hydraulic motor 32. The hydraulic motor 32 drives the fan impeller 31 to rotate at high speed, generating negative pressure to draw the dust-laden airflow from the dust removal section 1. After being moistened by the spray frame 11, captured by the filter screen 12, and separated by the dehydration section 2, the clean airflow is discharged from the silencer section 4.

[0040] When the dust collector continues to run, the filter screen 12 gradually becomes clogged, or the surface of the dehydration section 2 becomes sticky, causing the system resistance to increase, the load pressure of the hydraulic motor 32 increases accordingly. The LS feedback oil circuit 51 feeds back the load pressure downstream of the throttle valve 58 (i.e., the inlet pressure of the hydraulic motor 32) to the LS control port of the load-sensitive variable pump 52 in real time. The internal control mechanism of the load-sensitive variable pump 52 compares the feedback pressure with the 1~2MPa pressure difference preset by the internal spring, and automatically increases or decreases the swashplate angle, thereby adjusting the pump's displacement in real time, so that the pump outlet pressure automatically increases (or decreases), and always keeps the pressure difference ΔP before and after the throttle valve 58 constant within the range of 1~2MPa.

[0041] Since the pressure difference ΔP is constant, the flow rate of the hydraulic system is calculated using the following formula:

[0042] Where Q is the flow rate through throttle valve 58, C is the flow coefficient, A is the fixed flow area of ​​throttle valve 58, and ρ is the hydraulic oil density. When C, A, ρ, and ΔP are all kept constant, the flow rate Q remains completely constant, thereby ensuring that the actual effective flow rate supplied to the quantitative hydraulic motor 32 is constant, the speed of the hydraulic motor 32 is constant, and consequently the speed of the fan impeller 31 is constant, and the fan air volume and dust removal capacity remain constant.

[0043] When a system malfunction causes excessive pressure, safety valve 56 automatically opens to overflow, ensuring that hydraulic system 5 is not damaged.

[0044] The entire control process requires no electronic sensors, controllers, or frequency converters. It achieves closed-loop automatic adjustment entirely through the mechanical-hydraulic feedback mechanism of the load-sensitive variable pump 52 and the LS feedback oil circuit 51. It features a simple structure, high reliability, and good explosion-proof safety. It is particularly suitable for the harsh environment of coal mines, which are humid, dusty, and have limited space. It can maintain a constant fan speed and air volume throughout its entire life cycle, even when the filter screen is clogged and the resistance continues to rise. It completely solves the technical problem of "the greater the resistance, the smaller the air volume" in traditional dust collectors, and achieves stable and efficient dust control.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A constant air volume hydraulic dust collector for mining, comprising a dust collection section, a dehydration section, a fan section, and a noise reduction section arranged sequentially, characterized in that: The fan section includes a fan impeller and a fixed-displacement hydraulic motor, which drives the fan impeller to rotate. A hydraulic system is connected to the fixed-displacement hydraulic motor, which includes an LS feedback circuit forming a circulating oil circuit, a load-sensitive variable pump, an oil tank, a suction filter, a motor, a main oil circuit filter, and a throttle valve. The motor drives the load-sensitive variable pump to draw oil from the oil tank through the suction filter. The variable pump outputs pressurized oil, which drives the hydraulic motor through the main oil circuit filter and the throttle valve. The LS feedback circuit connects downstream of the throttle valve to the LS control port of the variable pump, maintaining a constant pressure difference between the pump outlet pressure and the load pressure at 1~2 MPa to ensure constant flow rate and constant fan impeller speed.

2. The constant air volume mine hydraulic dust collector according to claim 1, characterized in that, The hydraulic system maintains a constant pressure difference ΔP across the throttle valve, ensuring that the flow rate Q through the throttle valve depends only on the fixed flow area A of the throttle valve and is independent of changes in load pressure. The flow rate calculation formula is as follows: Where C is the flow coefficient and ρ is the hydraulic oil density.

3. The constant air volume hydraulic dust collector for mining as described in claim 1, characterized in that, The LS feedback oil circuit senses the downstream load pressure in real time and connects to the control port of the variable pump to achieve automatic pressure compensation; the load-sensitive variable pump automatically adjusts the swashplate angle and changes the displacement according to the pressure of the LS feedback oil circuit and the pressure difference set by the internal spring.

4. The constant air volume hydraulic dust collector for mining as described in claim 1, characterized in that, The hydraulic system also includes a safety valve connected to the outlet of the load-sensitive variable pump to protect the system from overpressure damage.

5. The constant air volume hydraulic dust collector for mining according to claim 1, characterized in that, The dust removal section includes a spray frame and a filter screen. The spray frame is equipped with spiral nozzles located upstream of the filter screen, 100-150mm away from the filter screen, and the spray field covers the surface of the filter screen.

6. The constant air volume mine hydraulic dust collector according to claim 5, characterized in that, The filter screen adopts a multi-layer metal mesh combination, including at least one layer of 4-mesh metal mesh as the skeleton, located on the outermost layer, providing structural support; at least 4 to 6 layers of 50-mesh metal mesh are located in the inner layer, which play a filtering role.

7. The constant air volume hydraulic dust collector for mining according to claim 1, characterized in that, The dewatering section adopts a corrugated plate structure, connecting the dust removal section outlet and the fan section inlet, and the bottom drain outlet discharges the dust-water mixture.

8. The constant air volume mine hydraulic dust collector according to claim 1, characterized in that, The dehydration air velocity in the dehydration section is 5~7m / s.

9. The constant air volume hydraulic dust collector for mining according to claim 5, characterized in that, The filter screen of the dust removal section is arranged at an angle of 50 to 80 degrees to the horizontal and is inclined along the air inlet direction.

10. A control method for a constant air volume mine hydraulic dust collector as described in any one of claims 1 to 9, characterized in that, A load-sensitive variable pump drives a fixed-displacement hydraulic motor. The downstream load pressure is sensed in real time through the LS feedback oil circuit. The variable pump automatically adjusts the displacement according to the feedback pressure and the set pressure difference to maintain a constant pressure difference of 1~2MPa between the pump outlet pressure and the load pressure. This ensures a constant flow through the throttle valve, thereby keeping the hydraulic motor speed and the fan impeller speed constant.

11. The control method according to claim 10, characterized in that, When the resistance of the dust collector system increases, the load pressure rises, and the variable pump automatically increases the output pressure to compensate for the pressure difference change and maintain a constant flow rate.

12. The control method according to claim 10, characterized in that, The set differential pressure is achieved through an internal spring in the variable pump. The flow rate calculation formula for the hydraulic system is: Where Q is the flow rate; C is the flow coefficient, which is related to the orifice type; and A is the flow area. It is the pressure difference before and after the throttling orifice; ρ is the density of the liquid; The constant pressure difference means that the flow rate depends only on the flow area of ​​the throttle valve and is independent of load changes.

13. The control method according to claim 10, characterized in that, The LS feedback oil circuit connects downstream of the throttle valve to the LS control port of the variable pump, providing real-time load pressure feedback to achieve automatic adjustment.

14. The control method according to claim 10, characterized in that, An electric motor drives a variable pump to draw oil from the oil tank. After being filtered by a suction filter, the pump outputs pressurized oil, which is then supplied to the hydraulic motor through a main oil circuit filter and a throttle valve.

15. The control method according to claim 10, characterized in that, The safety valve is connected to the outlet of the variable pump and overflows when the system pressure is too high, protecting the hydraulic system from damage.

16. The control method according to claim 10, characterized in that, The control method is applied to dust collectors in coal mine working faces. When the filter screen is clogged or the dehydration section is stuck, causing the resistance to increase, the fan impeller speed is automatically maintained at a constant speed.

17. The control method according to claim 10, characterized in that, Variable displacement pumps change the displacement by adjusting the swashplate angle, thus responding to load changes and ensuring stable dust removal capacity.

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