JPH029851B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to grinding mills, and more particularly to improvements in center-fed material grinding mills having a closed bottom and opposing sides for the ground material.

Prior Art and Problems A relevant prior art is U.S. Pat. No. 2,931,581, in which the material to be crushed is fed with air to the same side of the rotor, and the rotor receives the fine material resulting from the crushing. A rotary crusher is described which acts as a fan lifting upwards with the help of air. The crusher is equipped with a classifier vertically above the crushing rotor and is provided with means for returning heavy oversized material to the chamber for further crushing. Return of heavy and oversized material is determined by gravity separation from the classifier.

Another example of prior art is in U.S. Pat. No. 1,104,121, in which a rotor is supplied with material to one side of a grinding chamber and air is circulated by a fan at separated locations circumferentially of the grinding chamber. The rotor then lifts the crushed material into a classification chamber with spaced outlets above, where it is configured to be captured depending on its size and the distance the material is thrown from the chamber. Yet another example of the prior art is shown in Japanese Patent No. 36-4084, dated February 27, 1936, which has somewhat similar construction of working parts and body structure to that disclosed in U.S. Pat. No. 2,931,581. ing.

Less related patents include US Pat. No. 3,794,251 and US Pat. No. 3,826,208. In these patents, the grinding chamber has a closed bottom and a central feed through the ventilated throat, with the air supply located at the bottom of the throat and at the top of the grinding chamber.

An important object of the present invention is to provide a simple mill configured to grind and agitate the material in the grinding phase, in which the drying medium is ground into the grinding material, which is placed in the grinding chamber at two points on both sides of the material feed and the drying medium feed. The purpose is to crush and dry the material by introducing the flow into and out of the mill, which is divided into two streams and passes through the mill.

SUMMARY OF THE INVENTION The present invention comprises a mill base frame having spaced apart sidewalls; a rotating shaft operatively carried by a pair of opposing sidewalls; and a group carried on the shaft at a location spaced apart from the pair of sidewalls. a material crushing element; extending between the pair of sidewalls;
and a closed semi-cylindrical liner surrounding a group of grinding elements; forming a cylindrical extension of the closed liner and having side edges spaced from the pair of sidewalls; forming a generally cylindrical material grinding chamber having axially spaced openings at the top of the closed liner adjacent the pair of sidewalls, and having a spaced peripheral edge at the top of the closed liner; a convoluted liner forming a ventilated opening to the grinding chamber; a convoluted liner coupled to the mill base frame and opening adjacent to the ventilated opening of the convoluted liner centrally between the pair of side walls of the grinding chamber; a material feeding device that cooperates with the material grinding elements in the grinding chamber to gradually feed the material in the grinding chamber axially and discharge it through the axially spaced openings adjacent the pair of side walls; a mill on said base frame provided with a dry air intake plenum in communication with said grinding chamber through said spiral liner opening and also in communication with the crushed material discharged through said axially spaced opening; a superstructure; located in the mill superstructure to receive ground material moved by air from the grinding chamber;
Also communicating with the expansion chamber is an expansion chamber located for removing air and pulverized material from the pulverizing chamber and for returning oversized material to the pulverizing chamber through the ventilate inlet opening along with a drying medium. The present invention provides a material grinding mill comprising a means for classifying materials.

With the configuration of the invention, the incoming material is introduced substantially towards the center of the grinding chamber, so that the material is forced laterally along the rotor in the grinding chamber towards the side outlet, while at the same time In which the drying medium is better utilized.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Presently preferred material grinding mill features include opposing side walls 11 and a semi-cylindrical bottom liner 12 extending between the side walls 11 and surrounding the bottom of the grinding chamber 13 . The base frame 10 extends axially in the chamber 13 and supports the shaft 1 carried by suitable bearings (FIG. 2).
4 and a rotating assembly of hammers 15 fixed to shaft 14 between retainers 16 and 16. Any suitable hammer may be used.

The mill includes a cylindrical spiral liner 18 which is supported in an adjustable carrier 19 so as to be able to move closer to the circular orbit of the hammer 15 as wear progresses or when a stronger vacuum or suction is required in the section 29. includes a superstructure 17 attached to the base frame surrounding the base frame. The volute 18 and its carrier 19 do not extend as far as the side wall 11, but instead form a closed liner 1.
It is narrower than 2 and only extends between the faces of the hammer. The volute 18 can be moved in the superstructure 17 about a pivot 20 by means of a suitable adjustment mechanism 21. The spiral liner 18 extends along the trajectory of the hammer 15 and has a bulging edge 18A at its leading edge that approaches the trajectory of the hammer 15 in the grinding chamber and accelerates the flow there. It is provided. The opening of the hammer path is located off edge 18A, opposite material supply pipe 22 extending from hopper 23 to inlet 24, and located near the center of the width of the grinding chamber. The material is moved into the grinding chamber 12 by an auger screw driven by a suitable motor 26.

The spiral liner 18 is narrower than the bottom liner 12 (FIG. 2), so that at least one
A space is opened. Preferably, a narrow spiral liner 18 is used to create a space on both sides of the wall 11.

A portion of the superstructure 17 consists of an air plenum 27 with a supply duct 28 inlet. A material drying medium or hot air of inert nature is introduced into the plenum, flows downward through the volute 18 and combines with the material coming from the feed pipe 22 at the inlet, which acts as a ventilate throat 29 under negative pressure. be combined. The negative pressure is generated by the fan effect of the hammer 15 passing through the volute 18 and the closely fitted edge 18A, with the ventilary throat 2
At 9, suction is applied. Another part of the superstructure 17 is an expansion chamber for the ground material and air, which flows from the throat 29 of the grinding chamber 12 to a flange 31 adapted to form a connection to a transition duct section 32. A connected rectangular outlet passage 30 is provided, with the transition duct section 32 changing its shape from rectangular at flange 31 to circular at outlet flange 33.

The flange 33 is a known spinner separator 34.
The spinner separator is driven by a common transmission 37 having a rotating fan 35 in a casing 36 extending externally and having a drive shaft 38 connected to a motor 39. It is configured like this. The fan 35 fluidizes the flow of the crushed material, moving the heavier, larger particles to the outer periphery of the casing 36 where they fall by gravity through the ventilary throat 29 into the crushing chamber for further finerization by the hammers 15. It has a blade for A final material outlet 40 is located at the top of the casing 36, which outlet may be connected to a dump or the pulverized material may be sent to a burner and used as fuel.
A fan or blower may be connected to the hot air inlet duct 28 or to the classifier outlet 40.

The side view of FIG. 1 shows the material feed channel and the flow path for the drying medium, while FIG. has been done. As a result of this configuration, the more material that comes in and is crushed by the rotor hammer, the more the material that comes in is divided into two parts and laterally directed toward the ends of the shaft 14 of the side wall 11. This acts to forcibly move the object. The material thus forced out is simultaneously brought into contact with the drying medium entering the throat 29 before moving vertically on the opposite side. The side flow reaches the outlet passage 30, while a part of it recombines with the flow on the volute 18 along the dashed line and is sucked back into the grinding chamber. This configuration allows for the creation of multiple flow paths that improve the drying of the material and the comminution of the material in the grinding chamber. The channels through which the pulverized material and the drying medium flow are vertically separated, giving the drying medium more time to perform its drying action.

The operation of the mill is such that even beds of heavy materials can be accepted into the grinding chamber. As the bed builds up, dry air forced into the grinding chamber by ventilating action mixes with the material, forcing the heavy material bed to move along the rotor axis 14 and clear the final layer from the opposite side wall 11 of the grinding chamber. is discharged.
The material and air reaching the side wall space 41 are forced upward by the air on opposite sides of the plenum chamber 27 and the expansion chamber 30, and the material is dried by the incoming hot air medium while being accelerated in the upward air flow. is continued and diluted again. Expansion chamber 30 by air
The pulverized mass of material lifted up into the duct section 32 partially contains oversized material, which is forced outward by centrifugal force when it reaches the spinner fan blade 35. pushed away,
It falls by gravity back into the expansion chamber through the duct section 32 and is forced into the center of the expansion chamber by the upward flow of crushed material on the side walls. The material returned in this way is too large in size.
The powder is guided straight into the grinding chamber by the above-mentioned negative pressure, and is further pulverized. The flow through the ventilator throat acts to increase the velocity of the air and returned oversized material so that they are forced into the screw impeller 25.
is mixed with the incoming material, thereby forcing the contents of the grinding chamber to move laterally along axis 14 and assisting in its evacuation through side wall surface 41. The characteristics of the mill described above are assisted by the supply of hot air, resulting in a continuous displacement action of the material during the grinding process;
Eventually the material reaches the side wall surface 41 and is then moved according to the upward flow pattern described above.

Although this disclosure indicates preferred configurations embodying the principles of the invention, it also encompasses variations that accomplish the same or substantially the same purpose. One alternative is to create only one side space by appropriately unrolling the spiral liner so that it abuts only one side wall.

[Brief explanation of drawings]

1 is a schematic partial cross-sectional view of a material grinding mill for carrying out the principles of the present invention, and FIG. 2 is a partial cross-sectional view taken along line 2--2 in FIG. 11...Side wall, 12...Bottom liner, 13...
Grinding chamber, 14... shaft, 15... hammer, 16...
Retainer, 17... Upper structure, 18... Spiral liner, 19... Adjustable assembly, 20... Pivotal part, 21... Adjustment mechanism, 22... Material supply pipe, 2
3...Hotsupa, 24...Inlet, 26...Motor,
27... Plinum, 28... Supply duct, 29...
... Bench Lily throat, 30... Exit passage, 3
1...Flange, 32...Transition duct part, 33
...Exit flange, 34...Spinner separator,
35... Juan, 36... Casing, 37...
Transmission unit, 38... Drive shaft, 37... Motor, 40
……Exit.

Claims (1)

Claims: 1. A mill base frame having spaced apart side walls 11; a rotating shaft 19 operatively carried by the opposing pair of side walls;
and a group of material grinding elements 15 carried on the shaft at a location spaced from the pair of side walls 11; a closed semi-cylindrical liner 12 extending between the pair of side walls and surrounding the group of grinding elements; an opening forming a cylindrical extension of the closed liner and having a side edge spaced apart from the sidewall pair 11 and further axially spaced along with the closed liner adjacent the sidewall pair 11; forming a generally cylindrical material grinding chamber 13 having an upper part of the closed liner 12;
The grinding chamber 1 has peripheral edges 18A spaced apart from each other.
3; a spiral liner 18 connected to the mill base frame and centrally between the pair of side walls 11 of the grinding chamber 13; opening adjacent and cooperating with the material grinding element 15 in the grinding chamber 13 to gradually feed the material in the grinding chamber in the axial direction;
Material supply devices 22, 23, 26 for discharging from the axially spaced openings adjacent to the pair of side walls 11;
and; provided with a dry air intake plenum 27 communicating with the grinding chamber 13 through a ventilated opening 29 in the spiral liner and also communicating with the ground material discharged through the axially spaced opening. a mill superstructure 17 on the base frame; positioned in the mill superstructure to receive ground material moved by air from the grinding chamber 13;
and an expansion chamber 32 located for removing air and pulverized material from the grinding chamber; in communication with the expansion chamber, oversized material along with a drying medium passes through the ventilate inlet opening 29 to the grinding chamber 13.
A material grinding mill comprising means 34 for classifying the ground material to be returned to the pulverized material. 2. The air intake plenum (27) is oriented to intersect the air-lifted flow of ground material from the axially spaced openings adjacent the pair of side walls (11). Grinding mill for the listed materials. 3 the material grinding element 1 carried by the shaft 14;
A material grinding mill according to claim 1 or 2, wherein 5 is rotated in a direction moving closer to the spiral liner edge 18A, inducing a suction effect of returning oversized material to the grinding chamber. . 4. A material grinding mill as claimed in claim 1, including an inlet passage 28 for introducing hot material drying air and directing it to the air inlet plenum 27 and the spiral liner 18. 5 the spiral liner 18 gradually crushes the grinding element 15
, the leading edge of the crushing element 1
5, so that the velocity of the material and hot air passing through the leading edge is accelerated, with oversized particles being drawn down into the grinding chamber 13. A material grinding mill as described in any one of the above. 6. The material grinding mill of claim 4, wherein the leading edge of the spiral liner is formed with a convex surface 18A that is closer to the grinding element 15 than other surfaces of the spiral liner.