Permanent-magnet variable-loading-force medium-speed coal mill

Abstract

The embodiment of the invention provides a permanent-magnet variable-loading-force medium-speed coal mill. The permanent-magnet variable-loading-force medium-speed coal mill comprises a milling cylinder; the permanent magnet variable loading force regulation and control equipment is arranged on the milling cylinder; the grinding disc is arranged in the grinding cylinder; the grinding roller is arranged in the grinding cylinder, and the grinding roller and the permanent magnet variable loading force regulation and control equipment are correspondingly arranged; wherein the permanent magnet variable loading force regulation and control equipment is used for providing adjustable loading force and acting the adjustable loading force on the grinding roller so as to adjust the pressing acting force between the grinding roller and the grinding disc. In the invention, the adjustable loading force is provided through the permanent magnet variable loading force regulation and control equipment, so that the pressing acting force between the grinding roller and the grinding disc is regulated. Through the permanent magnet variable loading force regulation and control equipment, the pressing acting force between the grinding roller and the grinding disc can be accurately controlled, so that the coal grinding process is optimized, and the coal grinding efficiency is improved.

Description

Technical Field

[0001] The embodiments of the present disclosure belong to the technical field of medium-speed coal mills for coal-fired power station boilers, and specifically relate to a permanent magnet variable loading force medium-speed coal mill. Background Art

[0002] The pulverizing system is one of the most important auxiliary equipment of coal-fired power units. The coal required for boiler combustion is dried and ground into a suitable particle size through the pulverizing system and then transported to the combustion system for the next reaction.

[0003] The medium-speed coal mill pulverizing system is the most widely used type of pulverizing system in power station boilers. For medium-speed coal mills, the internal rollers of the coal mill need to have sufficient loading force applied to them to ensure that the raw coal in the gap between the rollers and the grinding discs is ground into qualified coal powder and supplied to the outside. Among the existing medium-speed coal mill equipment, there are types that provide loading force through hydraulic systems and types that provide loading force through spring systems. Both types of medium-speed coal mills have a wide range of application performance.

[0004] However, for spring-loaded medium-speed coal mills, the spring itself is not adjustable, so the coal mill is operated under fixed loading conditions, which reduces the adjustment performance of the coal mill in one dimension. For hydraulically loaded medium-speed coal mills, the transmission of hydraulic system pressure must be achieved with the help of tie rods and mechanical mechanisms. Tie rod breakage accidents often occur, affecting the stability of the equipment.

[0005] In view of the practical problems existing in the above-mentioned equipment, designing a variable loading system that can be flexibly adjusted and stably operated is a technical problem that urgently needs to be solved. Summary of the invention

[0006] The embodiments of the present disclosure aim to solve at least one of the technical problems existing in the prior art and provide a permanent magnet variable loading force medium speed coal mill.

[0007] One aspect of the embodiments of the present disclosure provides a permanent magnet variable loading force medium speed coal mill, comprising: a mill drum;

[0008] A permanent magnet variable loading force regulating device is arranged on the grinding cylinder;

[0009] A grinding disc, arranged in the grinding cylinder;

[0010] A grinding roller is arranged in the grinding cylinder, and the grinding roller is arranged corresponding to the permanent magnetic variable loading force regulating device;

[0011] The permanent magnet variable loading force regulating device is used to provide an adjustable loading force and act on the grinding roller to adjust the pressing force between the grinding roller and the grinding disc.

[0012] Optionally, the permanent magnet variable loading force control device includes a rotating mechanism and a permanent magnet magnetic assembly kit;

[0013] The rotating mechanism is rotatably connected to the wall of the grinding cylinder, and the rotating mechanism has an annular cavity;

[0014] The permanent magnet set comprises a static permanent magnet set and a dynamic permanent magnet set; along the radial direction of the grinding cylinder, the static permanent magnet set can be slidably arranged on the cylinder wall of the grinding cylinder and corresponds to the position of the grinding roller; the dynamic permanent magnet set is arranged on the inner wall of the annular cavity and is arranged opposite to the static permanent magnet set with the same pole;

[0015] According to the magnetic repulsion generated by the same poles of the moving permanent magnet set and the static permanent magnet set being arranged opposite to each other, the static permanent magnet set is moved radially along the grinding cylinder and drives the grinding roller to move, so as to adjust the pressing force between the grinding roller and the grinding disc.

[0016] Optionally, the rotating mechanism comprises a rotating drum and an adjusting member arranged on the rotating drum; the rotating drum has the annular cavity;

[0017] The outer wall of the grinding cylinder is provided with a guide rail; one end of the rotating cylinder close to the wall of the grinding cylinder is provided with a slide groove adapted to the guide rail; the rotating cylinder and the grinding cylinder are rotatably connected by the adapted installation of the slide groove and the guide rail;

[0018] The adjusting member is used to drive the rotating drum to rotate on the grinding drum, so as to adjust the magnetic repulsion between the moving permanent magnet set and the static permanent magnet set.

[0019] Optionally, the static permanent magnet kit includes a static permanent magnet group, a sliding cylinder and an abutment member; a sliding hole is provided on the cylinder wall of the grinding cylinder;

[0020] The slide cylinder is inserted into the slide hole, the static permanent magnet group is arranged at the first end of the slide cylinder, and the abutment member is arranged at the second end of the slide cylinder; the abutment member is used to abut against the grinding roller;

[0021] Wherein, the slide cylinder moves in the radial direction of the grinding cylinder according to the magnetic repulsion force, so that the abutment member abuts against the grinding roller to adjust the pressing force between the grinding roller and the grinding disc.

[0022] Optionally, there are multiple moving permanent magnet sets; around the axial direction of the rotating drum, multiple moving permanent magnet sets are arranged on the inner wall of the annular cavity at intervals;

[0023] There are multiple static permanent magnet groups; around the axial direction of the slide cylinder, multiple static permanent magnet groups are arranged in a ring at intervals at the first end of the slide cylinder;

[0024] Wherein, the plurality of moving permanent magnet sets and the plurality of static permanent magnet groups are arranged in one-to-one correspondence.

[0025] Optionally, the moving permanent magnet set is in a bar shape, and the moving permanent magnet set comprises a first moving magnet group and a second moving magnet group which are arranged opposite to each other;

[0026] The first moving magnet group and the second moving magnet group respectively include a plurality of moving permanent magnets arranged along the length direction of the moving permanent magnet set.

[0027] Optionally, along the length direction of the moving permanent magnet set, the width dimensions of the moving permanent magnet set are equal; correspondingly, the magnetic moments between the moving permanent magnets of the first moving magnetic group and the moving permanent magnets of the second moving magnetic group gradually increase.

[0028] Optionally, along the length direction of the moving permanent magnet set, the spacing between the first moving magnetic group and the second moving magnetic group is equal; and the width dimensions of a plurality of the moving permanent magnets corresponding to the first moving magnetic group and the second moving magnetic group are gradually reduced.

[0029] Optionally, the repulsive force between the static permanent magnet kit and the dynamic permanent magnet kit satisfies the conditional formula:

[0030] f(M j ,M dp ,r)=k×(M j ×M dp ) / r 2 ,

[0031] Among them, f(M j ,M dp , r) is the magnetic repulsion between the moving permanent magnet set and the static permanent magnet set, r is the distance between the moving permanent magnet set and the static permanent magnet set, k is the magnetic repulsion constant, M j is the effective magnetic moment of the static permanent magnet set, M dp is the effective magnetic moment of the moving permanent magnet set;

[0032] Among them, the constraint condition is: 0.8×F min ≤f(M j ,M dp ,r)≤1.5×F max , design the static permanent magnet kit M j The effective magnetic moment range.

[0033] Optionally, the repulsive force between the static permanent magnet set and the dynamic permanent magnet set

[0034] Satisfy the conditions:

[0035] f(M j ,M dp ,r+h)=k×(Mj ×M dp ) / (r+h) 2 ,

[0036] Among them, f(M j ,M dp , r+h) is the magnetic repulsion between the moving permanent magnet set and the static permanent magnet set, r is the distance between the moving permanent magnet set and the static permanent magnet set, h is the distance between the grinding roller and the grinding disc, k is the magnetic repulsion constant, M j is the effective magnetic moment of the static permanent magnet set, M dp is the effective magnetic moment of the moving permanent magnet set;

[0037] Among them, the constraint condition is: 0.6×F min ≤f(M j ,M dp ,r+h)≤

[0038] 1.1×F max , design the moving permanent magnet kit M dp The effective magnetic moment range and the width dimension of a single moving magnet.

[0039] The beneficial effects of the embodiments of the present disclosure include:

[0040] In the present disclosure, an adjustable loading force is provided by a permanent magnetic variable loading force control device, thereby adjusting the pressing force between the grinding roller and the grinding disc. The permanent magnetic variable loading force control device can accurately control the pressing force between the grinding roller and the grinding disc, thereby optimizing the coal grinding process and improving the coal grinding efficiency. In addition, the loading force can be flexibly adjusted according to different types of coal and working conditions to ensure that the coal mill operates in the best state. By accurately controlling the pressing force, excessive wear of the grinding roller and the grinding disc caused by excessive pressure can be avoided, thereby extending the service life of the equipment. And reasonable loading force distribution can make the wear of the grinding roller and the grinding disc more uniform, further extending the service life of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a structural schematic diagram of a permanent magnetic variable loading force medium speed coal mill according to an embodiment of the present disclosure;

[0042] Figure 2 It is a structural schematic diagram of a permanent magnet variable loading force control device according to an embodiment of the present disclosure;

[0043] Figure 3 It is a partial structural schematic diagram of a static permanent magnet kit according to an embodiment of the present disclosure;

[0044] Figure 4 It is a schematic structural diagram of a moving permanent magnet kit according to an embodiment of the present disclosure.

[0045] In the figure, 1, grinding cylinder; 2, permanent magnet variable load force control device; 3, grinding disc; 4, grinding roller; 11, guide rail; 21, rotating mechanism; 22, static permanent magnet kit; 23, dynamic permanent magnet kit; 211, rotating cylinder; 212, adjusting member; 213, annular cavity; 221, static permanent magnet group; 222, sliding cylinder; 223, abutment member; 231, first dynamic magnet group; 232, second dynamic magnet group; 233, dynamic permanent magnet. DETAILED DESCRIPTION

[0046] In order to enable those skilled in the art to better understand the technical solution of the present disclosure, the present disclosure is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0047] The following is a further detailed description of the implementation methods of the present application in conjunction with the accompanying drawings and examples. The detailed descriptions and drawings of the following examples are used to illustrate the principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments. In the description of the present application, it should be noted that, unless otherwise specified, the meaning of "multiple" is more than two; the orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "inside", "outside", etc. is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not vertical in the strict sense, but within the error tolerance range. "Parallel" is not parallel in the strict sense, but within the error tolerance range.

[0048] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0049] like Figure 1-4 As shown, a permanent magnetic variable loading force medium speed coal mill comprises a grinding drum 1, a permanent magnetic variable loading force regulating device 2, a grinding disc 3 and a grinding roller 4. The permanent magnetic variable loading force regulating device 2 is arranged on the grinding drum 1, the grinding disc 3 is arranged inside the grinding drum 1, the grinding roller 4 is arranged inside the grinding drum 1, and the grinding roller 4 is arranged corresponding to the permanent magnetic variable loading force regulating device 2.

[0050] The permanent magnet variable loading force regulating device 2 is used to provide an adjustable loading force and act on the grinding roller 4 to adjust the pressing force between the grinding roller 4 and the grinding disc 3 .

[0051] In the present disclosure, an adjustable loading force is provided by a permanent magnetic variable loading force control device 2, thereby adjusting the clamping force between the grinding roller 4 and the grinding disc 3. Through the permanent magnetic variable loading force control device 2, the clamping force between the grinding roller 4 and the grinding disc 3 can be accurately controlled, thereby optimizing the coal grinding process and improving the coal grinding efficiency. In addition, the loading force can be flexibly adjusted according to different types of coal and working conditions to ensure that the coal mill operates in the best state. By accurately controlling the clamping force, excessive pressure that causes excessive wear of the grinding roller 4 and the grinding disc 3 can be avoided, thereby extending the service life of the equipment. And reasonable loading force distribution can make the wear of the grinding roller 4 and the grinding disc 3 more uniform, further extending the service life of the equipment.

[0052] In some embodiments, the permanent magnet variable loading force control device 2 includes a rotating mechanism 21 and a permanent magnet magnetic assembly kit. The rotating mechanism 21 is rotatably connected to the cylinder wall of the grinding cylinder 1, and the rotating mechanism 21 has an annular cavity 213.

[0053] The permanent magnet assembly kit includes a static permanent magnet assembly 22 and a dynamic permanent magnet assembly 23. Along the radial direction of the grinding cylinder 1, the static permanent magnet assembly 22 can be slidably arranged on the cylinder wall of the grinding cylinder 1 and corresponds to the position of the grinding roller 4. The dynamic permanent magnet assembly 23 is arranged on the inner wall of the annular cavity 213 and is arranged opposite to the static permanent magnet assembly 22 with the same pole.

[0054] According to the magnetic repulsion generated by the same-pole relative arrangement of the dynamic permanent magnet set 23 and the static permanent magnet set 22, the static permanent magnet set 22 moves radially along the grinding cylinder 1 and drives the grinding roller 4 to move, so as to adjust the clamping force between the grinding roller 4 and the grinding disc 3.

[0055] In the present disclosure, the pressing force between the grinding roller 4 and the grinding disc 3 can be precisely controlled by the magnetic repulsion between the moving permanent magnet set 23 and the static permanent magnet set 22, thereby achieving fine adjustment of the coal grinding process. The stability and adjustability of the magnetic repulsion ensure the stable operation of the coal mill under different working conditions, and improve the accuracy and consistency of coal grinding. Through precise control of the magnetic repulsion, excessive wear of the grinding roller 4 and the grinding disc 3 caused by excessive pressure can be avoided, thereby extending the service life of the equipment.

[0056] In some embodiments, the rotating mechanism 21 includes a rotating drum 211 and an adjusting member 212 disposed on the rotating drum 211 , and the rotating drum 211 has the annular cavity 213 .

[0057] The outer wall of the grinding cylinder 1 is provided with a guide rail 11, and one end of the rotating cylinder 211 close to the cylinder wall of the grinding cylinder 1 is provided with a slide groove adapted to the guide rail 11, and the rotating cylinder 211 and the grinding cylinder 1 are rotationally connected through the adaptation installation of the slide groove and the guide rail 11.

[0058] The adjusting member 212 is used to drive the rotating drum 211 to rotate on the grinding drum 1 to adjust the magnetic repulsion between the moving permanent magnet set 23 and the static permanent magnet set 22 .

[0059] In the present disclosure, the relative position between the moving permanent magnet set 23 and the static permanent magnet set 22 can be accurately adjusted by driving the rotating drum 211 to rotate through the adjusting member 212, thereby accurately controlling the magnitude of the magnetic repulsion. The design of the rotating mechanism 21 allows continuous adjustment, making the adjustment of the magnetic repulsion more flexible and accurate.

[0060] Furthermore, by precisely controlling the magnetic repulsion force, it can be ensured that the pressing force between the grinding roller 4 and the grinding disc 3 is always maintained within an optimal range, thereby improving the accuracy and stability of coal grinding.

[0061] In some embodiments, the static permanent magnet set 22 includes a static permanent magnet group 221 , a sliding cylinder 222 and an abutment member 223 , and a sliding hole is provided on the cylinder wall of the grinding cylinder 1 .

[0062] The slide cylinder 222 is inserted into the slide hole, the static permanent magnet group 221 is disposed at the first end of the slide cylinder 222, and the abutment member 223 is disposed at the second end of the slide cylinder 222, and the abutment member 223 is used to abut against the grinding roller 4;

[0063] The slide cylinder 222 moves in the radial direction of the grinding cylinder 1 according to the magnetic repulsion force, so that the abutment member 223 abuts against the grinding roller 4 to adjust the pressing force between the grinding roller 4 and the grinding disc 3 .

[0064] In the present disclosure, the position of the static permanent magnet group 221 can be precisely controlled through the design of the slide 222 and the abutment 223, so as to precisely adjust the pressing force between the grinding roller 4 and the grinding disc 3. The slide 222 moves in the radial direction of the grinding cylinder 1 according to the magnetic repulsion force, and can quickly respond to the change of the magnetic repulsion force to ensure the timely adjustment of the position of the grinding roller 4. The design of the slide 222 and the abutment 223 ensures that the pressing force between the grinding roller 4 and the grinding disc 3 is always maintained within the optimal range, thereby improving the accuracy and stability of coal grinding.

[0065] In some embodiments, there are multiple moving permanent magnet sets 23 , which are arranged around the axial direction of the rotating cylinder 211 at intervals on the inner wall of the annular cavity 213 .

[0066] There are multiple static permanent magnet groups 221 axially around the slide cylinder 222 , and the multiple static permanent magnet groups 221 are arranged at intervals in a ring at the first end of the slide cylinder 222 .

[0067] The plurality of moving permanent magnet sets 23 and the plurality of static permanent magnet groups 221 are arranged in one-to-one correspondence.

[0068] In the present disclosure, the annular layout of multiple dynamic permanent magnet sets 23 and multiple static permanent magnet groups 221 ensures uniform distribution of magnetic force in the radial direction of the grinding cylinder 1, avoiding the problem of excessive or weak local magnetic force. The uniform magnetic force distribution makes the pressing force between the grinding roller 4 and the grinding disc 3 more uniform, improving the consistency and stability of the coal grinding process.

[0069] The corresponding arrangement of the plurality of moving permanent magnet sets 23 and the static permanent magnet group 221 makes the adjustment of the magnetic force more precise, and the relative position of each magnet can be flexibly adjusted as needed, thereby achieving fine control of the pressing force.

[0070] In some embodiments, the moving permanent magnet set 23 is in a bar shape, and the moving permanent magnet set 23 includes a first moving magnet group 231 and a second moving magnet group 232 that are arranged opposite to each other.

[0071] The first moving magnet group 231 and the second moving magnet group 232 respectively include a plurality of moving permanent magnets 233 arranged along the length direction of the moving permanent magnet set 23 .

[0072] In the present disclosure, the first moving magnetic group 231 and the second moving magnetic group 232 respectively include a plurality of moving permanent magnets 233 arranged along the length direction of the moving permanent magnet set 23. This layout ensures uniform distribution of magnetic force in the radial direction of the grinding cylinder 1 and avoids the problem of excessive or weak local magnetic force.

[0073] The uniform magnetic force distribution makes the pressing force between the grinding roller 4 and the grinding disc 3 more uniform, thereby improving the consistency and stability of the coal grinding process.

[0074] The arrangement of multiple moving permanent magnets 233 makes the adjustment of the magnetic force more precise, and the relative position of each moving permanent magnet 233 can be flexibly adjusted as needed, thereby achieving fine control of the pressing force.

[0075] In some embodiments, along the length direction of the moving permanent magnet set 23, the width of the moving permanent magnet set 23 is equal, and the magnetic moments between the moving permanent magnets 233 of the first moving magnet group 231 and the moving permanent magnets 233 of the second moving magnet group 232 are gradually increased. Figure 4 , pointing upward from left to right along the moving permanent magnet set 23.

[0076] In the present disclosure, the width dimensions of the plurality of moving permanent magnets 233 corresponding to the first moving magnet group 231 and the second moving magnet group 232 are gradually reduced, and this design can ensure that the magnetic force is more evenly distributed in the length direction of the moving permanent magnet set 23. The gradually reduced width dimension design can reduce the excessive concentration of magnetic force in certain areas and avoid uneven pressing force caused by excessive local magnetic force.

[0077] The tapered width dimension design makes the magnetic force contribution of each moving permanent magnet 233 more balanced, and the relative position of each moving permanent magnet 233 can be flexibly adjusted as needed, thereby achieving fine control of the clamping force.

[0078] In some embodiments, along the length direction of the moving permanent magnet set 23, the spacing between the first moving magnet group 231 and the second moving magnet group 232 is equal. The width dimensions of the moving permanent magnets 233 corresponding to the first moving magnet group 231 and the second moving magnet group 232 are gradually reduced.

[0079] In the present disclosure, the width dimensions of the plurality of moving permanent magnets 233 corresponding to the first moving magnet group 231 and the second moving magnet group 232 are gradually reduced, and this design can ensure that the magnetic force is more evenly distributed in the length direction of the moving permanent magnet set 23. The gradually reduced width dimension design can reduce the excessive concentration of magnetic force in certain areas and avoid uneven pressing force caused by excessive local magnetic force.

[0080] The tapered width dimension design makes the magnetic force contribution of each moving permanent magnet 233 more balanced, and the relative position of each moving permanent magnet 233 can be flexibly adjusted as needed, thereby achieving fine control of the clamping force.

[0081] In some embodiments, the static permanent magnet group 221 is in a bar shape, and along the length direction of the static permanent magnet group 221, the static permanent magnet group 221 includes a plurality of static permanent magnets arranged at equal intervals.

[0082] In some embodiments, the repulsive force between the static permanent magnet set and the dynamic permanent magnet set satisfies the conditional formula:

[0083] f(M j ,M dp ,r)=k×(M j ×M dp ) / r 2 ,

[0084] Among them, f(M j ,M dp , r) is the magnetic repulsion between the moving permanent magnet set and the static permanent magnet set, r is the distance between the moving permanent magnet set and the static permanent magnet set, k is the magnetic repulsion constant, M j is the effective magnetic moment of the static permanent magnet set, M dp is the effective magnetic moment of the moving permanent magnet set.

[0085] Among them, the constraint condition is: 0.8×F min ≤f(M j ,M dp ,r)≤1.5×F max , design the static permanent magnet kit M jThe effective magnetic moment range.

[0086] In some embodiments, the repulsive force between the static permanent magnet set and the dynamic permanent magnet set satisfies the conditional formula:

[0087] f(M j ,M dp ,r+h)=k×(M j ×M dp ) / (r+h) 2 ,

[0088] Among them, f(M j ,M dp , r+h) is the magnetic repulsion between the moving permanent magnet set and the static permanent magnet set, r is the distance between the moving permanent magnet set and the static permanent magnet set, h is the distance between the grinding roller and the grinding disc, k is the magnetic repulsion constant, M j is the effective magnetic moment of the static permanent magnet set, M dp is the effective magnetic moment of the moving permanent magnet set.

[0089] Among them, the constraint condition is: 0.6×F min ≤f(M j ,M dp ,r+h)≤1.1×F max , design the moving permanent magnet kit M dp The effective magnetic moment range and the width dimension of a single moving magnet.

[0090] A specific example provided by the present disclosure includes:

[0091] The coal mill comprises a permanent magnetic variable loading force regulating device, which is used for adjusting and controlling the pressing force between the grinding roller and the grinding disc in the coal mill.

[0092] The permanent magnet variable load force control device includes a rotating mechanism and a permanent magnet magnetic assembly kit, and an adjustment mechanism (i.e., an adjustment member) arranged on the rotating mechanism. The permanent magnet magnetic assembly kit includes a moving permanent magnet kit and a static permanent magnet kit with the same poles arranged opposite to each other, wherein a magnetic repulsion force is generated between the two permanent magnets with the same poles arranged opposite to each other. The adjustment mechanism is used to adjust the rotation angle of the rotating mechanism, and then adjust the rotation position of the moving permanent magnet kit, wherein the magnetic moments between the permanent magnets on the moving permanent magnet kit at different positions are different, thereby generating different same-pole magnetic repulsion forces with the static permanent magnet kit.

[0093] The rotating mechanism is used to evenly bear the magnetic repulsion between the moving permanent magnet set and the static permanent magnet set, and the rotating mechanism is specifically a rigid rotating mechanism. The rigidity of the rotating mechanism itself is used to provide mechanical support to ensure that the radial position of the moving permanent magnet set relative to the coal mill barrel wall remains unchanged.

[0094] The moving permanent magnet sets are evenly arranged in multiple groups on the rotating mechanism along the circumferential direction (the same number as the grinding rollers), and are fixed to the inner wall of the annular cavity of the rotating mechanism respectively. The moving permanent magnet sets arranged on the inner wall of the annular cavity can rotate on the wall of the grinding cylinder together with the rotating mechanism. The static permanent magnet sets are slidably connected to the wall of the coal mill (the number of static permanent magnet sets is the same as that of the grinding rollers, and the positions correspond), and can move along the radial direction of the grinding cylinder on the wall of the coal mill.

[0095] The dynamic permanent magnet set and the static permanent magnet set are arranged opposite to each other with the same poles in the diameter direction of the coal mill barrel wall. During the rotation adjustment process of the dynamic permanent magnet set, a partial magnetic group with the same area as the static permanent magnet set is always maintained to cooperate with the static magnetic group to generate magnetic repulsion.

[0096] The moving permanent magnet set is evenly arranged in multiple groups along the circumferential direction of the rotating structure (consistent with the number of grinding rollers), and is fixedly connected to the inner wall of the rotating mechanism ring cavity, and can rotate on the coal mill barrel wall together with the rotating mechanism. The static permanent magnet set is slidably connected to the coal mill barrel wall (consistent with the number of grinding rollers and corresponding to the position), and can move along the radial direction of the coal mill barrel wall. The moving permanent magnet set and the static permanent magnet set are arranged opposite to each other with the same poles in the radial direction of the coal mill barrel wall.

[0097] An annular guide rail is arranged on the outer side of the cylinder wall of the coal mill, and the rotating mechanism has a slide groove adapted to the guide rail. The rotating mechanism utilizes the slide groove to rotate around the cylinder wall along the guide rail. An adjusting part is installed at the lower part of the rotating mechanism, and the adjusting part drives the rotating mechanism to rotate.

[0098] refer to Figure 4 , the moving permanent magnet set is designed as a variable magnetic moment strip structure, which includes a first moving magnet group and a second moving magnet group arranged relatively to each other. The width dimension of the moving permanent magnet set remains unchanged, and the width dimension of the moving magnet gradually decreases from one end to the other end of the moving permanent magnet set, that is, the magnetic moment gradually increases (decreases). In order to ensure that the force of the rotating structure is uniform, the moving magnet group adopts an end-to-end arrangement structure. Along the circumferential (incomplete) direction of the moving magnet group, the area of ​​the middle area where the moving magnet is not installed increases (decreases) successively, and the area where the moving magnet is installed is designed to be equal in width in the vertical width direction. In addition, the moving magnet group can also be designed according to a design method in which the width of the magnets at different positions is equal, but the effective magnetic moment gradually changes, that is, along the direction of the moving magnet, under the condition of the same magnet surface area, the effective magnetic moment gradually increases (decreases).

[0099] refer to Figure 3 In some embodiments, the static magnetic group is designed as a fixed magnetic moment structure.

[0100] In some embodiments, the size of the moving magnet group is larger than the size of the static magnet group.

[0101] The rotating structure is a cylindrical structure, and the dynamic permanent magnet sets are evenly arranged on the inner surface of the cylinder. The magnetic repulsion generated between each group of corresponding dynamic permanent magnet sets and static permanent magnet sets is equal and evenly distributed on the wall of the cylinder. All magnetic repulsion forces act along the normal direction of the cylinder wall (axial direction of the cylinder), thereby compensating each other and not generating forces on other directions of the cylinder.

[0102] As the rigid structure rotates, the magnetic repulsion between the dynamic permanent magnet assembly and the static permanent magnet assembly changes due to the variable magnetic moment design of the dynamic permanent magnet assembly, but the rotating structure can always maintain radial force balance.

[0103] After the moving permanent magnet set rotates synchronously under the traction of the adjusting part, the effective magnetic moment of the moving permanent magnet changes due to the variable magnetic moment design, so the magnetic repulsion between it and the static permanent magnet set also changes accordingly. The larger the magnetic moment of the effective moving magnetic group on the moving permanent magnet set that is directly opposite to the static permanent magnet set, the greater the magnetic repulsion between the moving permanent magnet set and the static permanent magnet set, which makes the force transmitted by the static permanent magnet set to the grinding roller greater, and the force transmitted by the grinding roller to the grinding disc greater, that is, the greater the coal mill loading force. On the contrary, the coal mill loading force is smaller.

[0104] The designed working distance between the dynamic permanent magnet set and the static permanent magnet set is r, the distance between the grinding roller and the grinding disc is h, and the minimum loading force during the coal mill startup phase is F min The maximum load force of coal mill operation is F max , the effective magnetic moment of the static permanent magnet set is M j , the effective magnetic moment of the moving permanent magnet set is M dp , the system design constraint 1 is:

[0105] 0.8×F min ≤f(M j ,M dp ,r)≤1.5×F max

[0106] Design M according to constraint 1 j ;

[0107] The constraint 2 of the system design is:

[0108] 0.6×F min ≤f(M j ,M dp ,r+h)≤1.1×F max

[0109] Design M according to constraint 2 dp The effective magnetic moment range and the width dimension of a single moving magnet.

[0110] The loading force adjustment is executed according to the step-by-step variable loading force strategy. The angle of each rotation of the adjustment mechanism is guaranteed to cross at least one minimum permanent magnet unit. The width of the minimum permanent magnet unit and the single-step adjustment angle of the actuator are reasonably designed according to this constraint.

[0111] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present disclosure, but the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and substance of the present disclosure, and these modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A permanent magnet variable loading force medium speed coal mill, characterized in that: include: grinding cylinder; A permanent magnet variable loading force regulating device is arranged on the grinding cylinder; A grinding disc, arranged in the grinding cylinder; A grinding roller is arranged in the grinding cylinder, and the grinding roller is arranged corresponding to the permanent magnetic variable loading force regulating device; The permanent magnet variable loading force regulating device is used to provide an adjustable loading force and act on the grinding roller to adjust the pressing force between the grinding roller and the grinding disc.

2. A permanent magnet variable loading force medium speed coal mill according to claim 1, characterized in that: The permanent magnet variable loading force control device comprises a rotating mechanism and a permanent magnet magnetic assembly kit; The rotating mechanism is rotatably connected to the wall of the grinding cylinder, and the rotating mechanism has an annular cavity; The permanent magnet assembly kit includes a static permanent magnet assembly kit and a dynamic permanent magnet assembly kit; Along the radial direction of the grinding cylinder, the static permanent magnet set can be slidably arranged on the cylinder wall of the grinding cylinder and corresponds to the position of the grinding roller; the dynamic permanent magnet set is arranged on the inner wall of the annular cavity and is arranged opposite to the static permanent magnet set with the same pole; According to the magnetic repulsion generated by the same poles of the moving permanent magnet set and the static permanent magnet set being arranged opposite to each other, the static permanent magnet set is moved radially along the grinding cylinder and drives the grinding roller to move, so as to adjust the pressing force between the grinding roller and the grinding disc.

3. A permanent magnet variable loading force medium speed coal mill according to claim 2, characterized in that: The rotating mechanism comprises a rotating drum and an adjusting member arranged on the rotating drum; the rotating drum has the annular cavity; The outer wall of the grinding cylinder is provided with a guide rail; one end of the rotating cylinder close to the wall of the grinding cylinder is provided with a slide groove adapted to the guide rail; the rotating cylinder and the grinding cylinder are rotatably connected by the adapted installation of the slide groove and the guide rail; The adjusting member is used to drive the rotating drum to rotate on the grinding drum, so as to adjust the magnetic repulsion between the moving permanent magnet set and the static permanent magnet set.

4. A permanent magnet variable loading force medium speed coal mill according to claim 3, characterized in that: The static permanent magnet set comprises a static permanent magnet group, a sliding cylinder and an abutment member; a sliding hole is arranged on the cylinder wall of the grinding cylinder; The slide cylinder is inserted into the slide hole, the static permanent magnet group is arranged at the first end of the slide cylinder, and the abutment member is arranged at the second end of the slide cylinder; the abutment member is used to abut against the grinding roller; Wherein, the slide cylinder moves in the radial direction of the grinding cylinder according to the magnetic repulsion force, so that the abutment member abuts against the grinding roller to adjust the pressing force between the grinding roller and the grinding disc.

5. A permanent magnet variable loading force medium speed coal mill according to claim 4, characterized in that: There are multiple moving permanent magnet sets; around the axial direction of the rotating drum, multiple moving permanent magnet sets are arranged on the inner wall of the annular cavity at intervals; There are multiple static permanent magnet groups; around the axial direction of the slide cylinder, multiple static permanent magnet groups are arranged in a ring at intervals at the first end of the slide cylinder; Wherein, the plurality of moving permanent magnet sets and the plurality of static permanent magnet groups are arranged in one-to-one correspondence.

6. A permanent magnet variable loading force medium speed coal mill according to claim 2, characterized in that: The moving permanent magnet set is in a bar shape, and comprises a first moving magnet group and a second moving magnet group which are arranged opposite to each other; The first moving magnet group and the second moving magnet group respectively include a plurality of moving permanent magnets arranged along the length direction of the moving permanent magnet set.

7. A permanent magnet variable loading force medium speed coal mill according to claim 6, characterized in that: Along the length direction of the moving permanent magnet set, the width dimensions of the moving permanent magnet set are equal; the width dimensions of a plurality of the moving permanent magnets corresponding to the first moving magnet group and the second moving magnet group are gradually reduced.

8. The permanent magnet variable loading force medium speed coal mill according to claim 6, characterized in that: Along the length direction of the moving permanent magnet set, the spacing between the first moving magnetic group and the second moving magnetic group is equal; correspondingly, the magnetic moment between the moving permanent magnets of the first moving magnetic group and the moving permanent magnets of the second moving magnetic group increases gradually.

9. A permanent magnet variable loading force medium speed coal mill according to claim 2, characterized in that: The repulsive force between the static permanent magnet set and the dynamic permanent magnet set satisfies the conditional formula: f(M j ,M dp ,r)=k×(M j ×M dp ) / r 2 , Among them, f(M j ,M dp , r) is the magnetic repulsion between the moving permanent magnet set and the static permanent magnet set, r is the distance between the moving permanent magnet set and the static permanent magnet set, k is the magnetic repulsion constant, M j is the effective magnetic moment of the static permanent magnet set, M dp is the effective magnetic moment of the moving permanent magnet set; Among them, the constraint condition is: 0.8×F min ≤f(M j ,M dp ,r)≤1.5×F max , design the static permanent magnet kit M j The effective magnetic moment range.

10. A permanent magnet variable loading force medium speed coal mill according to claim 2, characterized in that: The repulsive force between the static permanent magnet set and the dynamic permanent magnet set satisfies the conditional formula: f(M j ,M dp ,r+h)=k×(M j ×M dp ) / (r+h) 2 , Among them, f(M j ,M dp , r+h) is the magnetic repulsion between the moving permanent magnet set and the static permanent magnet set, r is the distance between the moving permanent magnet set and the static permanent magnet set, h is the distance between the grinding roller and the grinding disc, k is the magnetic repulsion constant, M j is the effective magnetic moment of the static permanent magnet set, M dp is the effective magnetic moment of the moving permanent magnet set; Among them, the constraint condition is: 0.6×F min ≤f(M j ,M dp ,r+h)≤1.1×F max , design the moving permanent magnet kit M dp The effective magnetic moment range and the width dimension of a single moving magnet.

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