JP2011088116A - Vertical roller mill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vertical roller mill capable of increasing reduction force without increasing thrust of a pressure roller unit. <P>SOLUTION: The vertical roller mill includes: a crushing table 9 which is housed on the lower part of a casing 1 and is rotatively driven; a plurality of roller pressing devices 3 each of which pressurizes the pressure roller 7 against the crushing table and crushes a lumpy material 12 on the crushing table; and a supply pipe 31 through which the lumpy material is supplied to the crushing table, wherein each of the plurality of roller pressing devices has a pressure roller unit 6 which is supported on the base end part and is freely obliquely movable, the pressure roller disposed on the tip of the pressure roller unit, a two-joint linkage 18 which performs connection between the midway part of the pressure roller unit and a reactive force support part and a pressure cylinder 4 connected to the intermediate connection pin 22 of the two-joint linkage, and the pressure cylinder is configured such that the thrust is made to act to bend the two-joint linkage and, thereby, the rolling force is generated between the pressure roller and the crushing table. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vertical roller mill that pulverizes massive coal, limestone, etc., and supplies it as a fine powder and as a fuel for boilers or as a raw material for cement.

  In a coal-fired boiler using coal as fuel, massive coal is pulverized by a vertical roller mill to form pulverized coal having a predetermined particle size, and the pulverized coal is supplied together with primary air to a burner that is a combustion apparatus.

  The vertical roller mill supplies massive coal onto a grinding table, presses a roller that rolls on the grinding table against the grinding table, and grinds the massive coal with the roller. The pulverized coal (hereinafter referred to as pulverized coal) is conveyed by primary air, but is classified in the vertical roller mill so that the pulverized coal supplied to the burner has a predetermined particle size. Classified by vessel.

  With reference to FIG. 3, a roller pressing device for pressing the roller against the crushing table in a conventional vertical roller mill will be described.

  In FIG. 3, reference numeral 1 denotes a casing, and a journal cover 2 is provided at the lower part of the casing 1 at a position equally divided into three circumferences, and each journal cover 2 is pressurized by a roller that passes through the journal cover 2 radially. An apparatus 3 is provided. The roller pressurizing apparatus 3 is mainly composed of a pressurizing cylinder 4 that is a hydraulic cylinder, a pressurizing roller unit 6 that can rotate in the vertical direction about a horizontal axis 5, and further pressurizing the pressurizing unit 3. The roller unit 6 includes a pressure roller 7 that is rotatable.

  The pressure roller unit 6 has a pressure receiving arm 8 extending upward, and the pressure cylinder 4 applies pressure to the pressure receiving arm 8.

  A crushing table 9 that is rotated by a driving device (not shown) is provided at the lower part of the casing 1, and a table segment 11 that forms a ring-shaped recess is provided on the upper surface of the crushing table 9. The pressure cylinder 4 is pressed against the recess of the table segment 11.

  Lumped coal 12 is supplied to the center of the crushing table 9, the crushing table 9 is rotated, and the pressure roller 7 rolls on the table segment 11 so that the lumped coal 12 is added. It is caught by the pressure roller 7 and crushed. The pulverized pulverized coal is blown up by the primary air blown from the blow-out port 13 and conveyed to a burner (not shown).

In the roller pressing device 3 described above, when the thrust F is applied by the pressing cylinder 4, the rolling force P by the pressing roller 7 is P = FR1 / R2 from the balance of the rotational moment.
Here, R1 represents the distance from the center of the horizontal shaft 5 to the line of action of thrust F, and R2 represents the distance from the center of the horizontal shaft 5 to the reduction point of the pressure roller 7.

  In the conventional roller pressure device 3, when the rolling force P is increased, 1) R1 is increased, 2) the hydraulic pressure of the pressure cylinder 4 is increased, or the pressure cylinder 4 is enlarged. Can be mentioned. However, when R1 is increased, the journal cover 2 and further the casing 1 are increased in size, which causes an increase in cost. Further, when the hydraulic pressure of the pressurizing cylinder 4 is increased or the pressurizing cylinder 4 is increased in size, the cost of the hydraulic system increases, and the journal cover 2 and the casing 1 are increased in size.

  In addition, in both cases 1) and 2), the journal cover 2 receives the reaction force of the rolling force, so that the strength of the journal cover 2 must be reinforced, and so on. It was.

JP-A-4-235755 JP-A-11-207202

  In view of such circumstances, the present invention increases the reduction force without increasing the thrust of the pressure roller unit, and reduces the reaction force to the pressure roller unit support portion to reduce the size of the pressure roller unit support portion. This is intended to reduce the size of the casing.

  The present invention includes a crushing table housed in a lower part of a casing and driven to rotate, a plurality of roller pressing devices that press a pressure roller against the crushing table to crush the lump on the crushing table, and the lump In the vertical roller mill comprising a supply pipe for supplying the pulverizing table to the crushing table, the roller pressure device is supported at a base end portion and is provided with a tiltable pressure roller unit, and provided at the tip of the pressure roller unit. The pressure roller, a two-bar link connecting the middle part of the pressure roller unit and the reaction force support unit, and a pressure cylinder connected to an intermediate connection pin of the two-bar link. The pressure cylinder relates to a vertical roller mill configured to generate a rolling force between the pressure roller and the grinding table by applying a thrust force so as to bend the two-bar link.

  According to the present invention, the reaction force support portion is located at the same level as the upper surface of the crushing table, and the pressure cylinder is a vertical roller mill disposed below the pressure roller unit. .

  According to the present invention, a crushing table housed in the lower part of the casing and driven to rotate, a plurality of roller pressing devices that press the pressure roller against the crushing table and crush the lump on the crushing table, In a vertical roller mill comprising a supply pipe for supplying a lump to the pulverization table, the roller pressure device is supported at a base end and is tiltable, and a tip of the pressure roller unit A pressure roller connected to an intermediate connection pin of the two-bar link; and a pressure cylinder connected to an intermediate connection pin of the two-bar link; The pressure cylinder is configured to generate a reduction force between the pressure roller and the pulverization table by applying a thrust force to bend the two-bar link, so that the thrust force of the pressure cylinder increases. Pressure roller Is transmitted, a large rolling force is obtained, also thrust simplifies the structure of the pressure cylinder supporting unit since may be small, it is possible to miniaturize. Further, when the reduction force is increased, it is possible to cope without increasing the pressure cylinder support portion and without increasing the capacity of the pressure cylinder.

  According to the invention, the reaction force support portion is located at the same level as the upper surface of the crushing table, and the pressure cylinder is disposed below the pressure roller unit. The vertical size of the mounting portion can be reduced, and the vertical roller mill can be reduced in size and the like.

It is a schematic sectional drawing of the vertical roller mill which concerns on the Example of this invention. (A) (B) is explanatory drawing about the effect | action of the force of the roller pressurization apparatus in this Example. It is a partial view showing a roller pressurizing device in a conventional vertical roller mill.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the thing equivalent to what was shown in FIG.

  First, referring to FIG. 1, an example of a vertical roller mill in which the present invention is implemented will be described.

  A sealed space is formed by the casing 1 erected on the base 15, and a pulverizing table 9 is installed below the space via a table driving device 16, and the pulverizing table 9 is fixed by the table driving device 16. Rotated at high speed. A table segment 11 having a concave groove 17 having a circular cross section is provided on the upper surface of the grinding table 9.

  A journal cover 2 is provided at a lower part of the casing 1 and at a required equal position, for example, a position divided into three equal circumferences, and each journal cover 2 is provided with a roller pressure device 3 so as to penetrate the journal cover 2. The roller pressing device 3 is provided in a radial arrangement.

  The pressure roller unit 6 has a pressure roller 7 that is rotatable at the tip, and is supported by the journal cover 2 via the horizontal shaft 5 at the base so as to be tiltable. The pressure roller 7 is pressed against the concave groove 17 of the table segment 11 by a pressure cylinder 4 described later.

  The upper end of the link set 18 is connected to the middle portion of the pressure roller unit 6 via an upper connecting pin 19, and the lower end of the link set 18 is attached to a reaction force support portion via a lower connecting pin 20. In this embodiment, the lower end of the link set 18 is connected to the bottom surface of the journal cover 2 via the lower connecting pin 20, and the reaction force support portion is at the same level as the upper surface of the pulverizing table 9. It is located at the periphery of the table 9.

  The link set 18 is a two-bar link, and the rod tip of the pressure cylinder 4 is connected to the intermediate connecting pin 22.

  The pressure cylinder 4 is positioned below the pressure roller unit 6, penetrates the journal cover 2 in the horizontal direction or substantially horizontal direction, and is supported by the journal cover 2. The intermediate connecting pin 22 is displaced in the horizontal direction by driving the pressure cylinder 4, that is, advancing and retreating of the rod, the distance between the upper connecting pin 19 and the lower connecting pin 20 is displaced, and the pressure roller 7 is Pressed by the table segment 11.

  A primary air chamber 25 is formed below the crushing table 9, and a classification chamber 26 is provided above the crushing table 9 inside the casing 1.

  A primary air supply port 27 is attached to the lower part of the casing 1, and the primary air supply port 27 is connected to a blower (not shown) and communicates with the primary air chamber 25. A nozzle ring 28 is provided around the crushing table 9, and a primary air outlet 13 is provided over the entire circumference of the nozzle ring 28.

  A coal supply / discharge portion 29 is provided on the upper side of the casing 1, and a pipe-like chute 31 is provided so as to penetrate the central portion of the coal supply / discharge portion 29. It extends to. Coal 12 is supplied to the chute 31, and the supplied coal 12 falls on the crushing table 9.

  A classifier 32 is rotatably provided in the middle of the chute 31, and the classifier 32 has strip-shaped blades 33 arranged at a required pitch in the circumferential direction. The classifier 32 is a rotation drive unit. 34 is rotated.

  A pulverized coal feed pipe 35 is connected to the coal feed / discharge part 29. The pulverized coal feed pipe 35 is connected to a boiler burner (not shown) and feeds the pulverized pulverized coal to the burner.

  Hereinafter, the operation of the vertical roller mill will be described.

  The pulverizing table 9 is rotated, and in the state where primary air is introduced from the primary air supply port 27, the massive coal 12 is introduced from the chute 31. The massive coal 12 flows down from the lower end of the chute 31 and is supplied onto the crushing table 9. The coal 12 on the crushing table 9 is pulverized by the pressure roller 7 to become pulverized coal, and the pulverized coal rises on the primary air that blows up through the outlet 13.

  The pulverized coal having a large particle size falls in the middle of ascent, and the pulverized coal having a predetermined diameter or less reaches the classifier 32.

  The primary mixed air that has reached the classifier 32 flows into the classifier 32 across the blade 33 that rotates about the chute 31, and further from the lower end opening of the coal supply / discharge section 29. It flows into the supply / discharge unit 29.

  When the primary mixed air crosses the blade 33, the pulverized coal having a large particle size collides with the blade 33 and falls. Only pulverized coal with a small particle size rides on the primary air and flows into the classifier 32, and further pulverized coal with a large particle size to which centrifugal force acts is classified and falls. Further, the pulverized coal bounced off by the blade 33 falls on the crushing table 9. The pulverized coal that has been classified and dropped is pulverized again by the pressure roller 7.

  Thus, only pulverized coal having a particle size smaller than a predetermined diameter is discharged from the pulverized coal feed pipe 35 through the coal supply / discharge section 29 and supplied to a burner (not shown) of the boiler.

  In the above description, the present invention has been described as a vertical roller mill for pulverized coal, but it goes without saying that the present invention can be implemented as a vertical roller mill for pulverizing cement raw materials.

  Next, regarding the pressure roller unit 6, the relationship between the thrust by the pressure cylinder 4 and the pressure applied by the pressure roller 7 will be described in comparison with the conventional pressure roller unit 6.

In FIG. 2A, if a horizontal thrust F is applied to the intermediate connecting pin 22 by the pressure cylinder 4, the vertical force F1 acting on the upper connecting pin 19 is:
F1 = F / 2 tan θ.

When the force of F1 acts on the upper connecting pin 19, considering the moment balance about the horizontal axis 5 with respect to the pressure roller 7, as shown in FIG.
L1 ・ F1 = L2 ・ P
P = L1 ・ F1 / L2
P = F ・ L1 / L2 ・ 2tanθ
= (L1 / L2) · (F / 2 tan θ)

  That is, the value of the rolling force P can be increased by increasing (L1 / L2) and decreasing 2 tanθ.

  The value of (L1 / L2) is determined by selecting somewhere in the pressure roller unit 6 for the upper connecting pin 19, and the pressure roller unit 6 for increasing (L1 / L2). And it is not necessary to change the support structure of the pressure roller unit 6 significantly.

  In order to reduce 2 tan θ, it is only necessary to reduce θ. For example, it is only necessary to change the length of the link, and the value of θ can be easily selected without significantly changing the structure. For example, the length of the link can be selected so that the upper connecting pin 19, the lower connecting pin 20, and the intermediate connecting pin 22 are in a straight line, and θ can be set to 0 without limit. Therefore, a large reduction force can be obtained by selecting θ.

  In the present embodiment, an increase in the reduction force can be easily realized by changing the length of the link in the link set 18 without increasing the thrust F of the pressure cylinder 4.

  Furthermore, when it is not necessary to increase the rolling force, the thrust of the pressure cylinder 4 can be reduced, and the small pressure cylinder 4 can be used.

  Further, since the pressure cylinder 4 is installed on the lower side of the pressure roller unit 6, the height of the journal cover 2 can be reduced, and the casing 1 and the vertical roller mill can be downsized. It becomes.

  Further, a reaction force of the force received by the link group 18 acts on the lower connection pin 20 and is further transmitted to the reaction force support portion via the lower connection pin 20. In the above embodiment, the lower connecting pin 20 is transmitted to the journal cover 2, the casing 1, and further to the base 15.

  Since the lower connecting pin 20 is provided in the bottom surface of the journal cover 2 and in the vicinity of the casing 1, the transmission path of the force to the casing 1 and further to the base 15 is shortened and simplified. The structure of the casing 1 and the structure of the casing 1 can be simplified, and it is not necessary to reinforce with high strength.

  Further, since the lower connecting pin 20 is located close to the base 15, it can be directly attached to the base 15. In this case, the structure of the journal cover 2 can be further simplified. Further, since the pressure cylinder 4 is provided under the journal cover 2, the moment acting on the journal cover 2 can be reduced, and the structure is simplified.

  Further, since the thrust of the pressure cylinder 4 may be small, the force to the journal cover 2 that bears the reaction force is further reduced.

  Next, the conventional roller pressure device 3 will be described. As described above, when the thrust F is applied to the pressure roller unit 6 by the pressure cylinder 4, the reduction force P by the pressure roller 7 is rotated. From the moment balance, P = FR1 / R2.

  Accordingly, in the conventional roller pressurizing device 3, if the reduction force P is increased without changing the thrust F of the pressurizing cylinder 4, R2 is reduced or increased by R1 from P = FR1 / R2. Will do.

  Since R2 is substantially determined by the size of the crushing table 9, the size of the pressure receiving arm 8, etc., if the rolling force P is increased, R1 is increased. For this reason, an increase in the rolling force P leads to an increase in the size of the roller pressurizing device 3. Further, although the reduction force P can be increased by increasing the capacity of the pressurizing cylinder 4, an increase in cost is required such as an increase in the hydraulic pressure of the hydraulic system.

  As described above, in the present invention, by applying a thrust force to the pressure roller unit 6 via the link, the reduction force of the pressure roller 7 can be increased without increasing the capacity of the pressure cylinder 4. It is possible to reduce the size of the roller pressure device 3 and the size of the journal cover 2 and the roller pressure device 3.

  Although the lower connecting pin 20 is provided on the bottom surface of the journal cover 2, it may be provided on the casing 1 or on the base 15. Furthermore, in the above-described embodiment, the bending direction of the link set 18 may be reversed, and the rod of the pressure cylinder 4 may be protruded so that a reduction force is applied to the pressure roller 7.

  In the above embodiment, the pulverization of coal has been described. Needless to say, the present invention can be applied to the pulverization of other lumps such as limestone.

DESCRIPTION OF SYMBOLS 1 Casing 2 Journal cover 3 Roller pressure apparatus 4 Pressure cylinder 5 Horizontal axis 6 Pressure roller unit 7 Pressure roller 9 Grinding table 18 Link assembly 19 Upper connection pin 20 Lower connection pin 22 Intermediate connection pin

Claims (2)

  A crushing table housed in a lower part of the casing and driven to rotate, a plurality of roller pressing devices for crushing the lump on the crushing table by pressing a pressure roller against the crushing table, and the lump on the crushing table In the vertical roller mill having a supply pipe for supplying to the pressure roller, the roller pressure device is supported by a base end portion and is tiltable, and the pressure roller unit provided at the tip of the pressure roller unit. A pressure roller, a two-bar link connecting the middle part of the pressure roller unit and the reaction force support unit, and a pressure cylinder connected to an intermediate connection pin of the two-bar link, A vertical roller mill characterized in that the pressure cylinder is configured to generate a rolling force between the pressure roller and the grinding table by applying a thrust force to bend the two-bar link.   2. The vertical roller mill according to claim 1, wherein the reaction force support portion is positioned at the same level as an upper surface of the crushing table, and the pressure cylinder is disposed below the pressure roller unit.

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