JPS5944105B2 - Disc-type fine grinder for synthetic resin grinding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is characterized in that the outer periphery has a small gap, for example 0.25 to 0.
．． A radial ring is attached to an annular portion near the outer periphery of opposite surfaces of a disk which faces each other with a gap of 0.05 mm and rotates in opposite directions at high speed, for example, at a relative speed of 150 to 250 m/s at the outer periphery. A large number of blades are arranged so that the gap in the direction of the center line of the disk between the cutting edge of the blade of one disk and the cutting edge of the blade of the other disk becomes narrower toward the outer periphery of the disk. and
It is an object of the present invention to provide a disc-type pulverizer capable of producing fine powder of, for example, 0.3 to 0.15 mm or less by cutting the surface of mainly thermoplastic synthetic resin particles supplied between discs. be.

When fixing one side of the left and right discs with a large number of blades as described above, and rotating only the other disc with a raw material supply port in the center, feeding the raw material is easy, but if the left and right discs have a large number of blades, The raw material grains between the blades of the plate rotate around the center line of the disc at a rotation speed that is approximately half the rotation speed of the high-speed rotating disc, so a large centrifugal force acts on these raw material grains. It is strongly pushed into the wedge-shaped gap between the blades of the left and right discs, which decreases toward the outer periphery of the disc, so the depth of cutting by the blades provided on the disc increases, producing fine powder. It is difficult to do so.

If the rotational speed of the disk is reduced too much, the discharge speed of the crushed material will decrease, resulting in a decrease in the crushing capacity, and the raw material, whose temperature has been raised by the heat generated by the crushing, will pass between the blades. The disadvantage is that it takes a long time and tends to be fused to the blade of the disc. When the left and right discs are rotated in opposite directions, the raw material between the blades of the left and right discs rotates at high speed around the center line of the disc and is strongly pushed into the wedge-shaped gap between the blades. It has been found that fine powder can be produced because the phenomenon of oxidation does not occur.

However, in this case, difficulties arise in supplying raw materials.
For example, if the shaft that rotates one side of the disk is hollow, and the raw material is supplied between the left and right disks by air flow, the rotational speed of the hollow shaft that rotates the disk with a diameter of 600 mm and a circumferential speed of 125 m/s is, for example, is about 4000r. Because of the high speed, the centrifugal force inside the hollow shaft causes the raw material to be firmly deposited on the inner wall, and cannot be transported in the axial direction by air flow, even if the shaft is perpendicular.

Since the diameter of this hollow shaft is larger than that of the other shaft in order to insert the raw material feed pipe inside, the bearing supporting it becomes large in size and rotates at high speed, resulting in a high temperature. This heat transfer from the bearing also raises the temperature of the hollow shaft, so that when a synthetic resin with a low melting point is pulverized, it may fuse to the inner wall of the hollow shaft. Therefore, it is also inappropriate to forcibly send out raw materials deposited on the inner wall of the hollow shaft by centrifugal force using a screw or the like. Even if you insert a raw material feed tube inside the hollow shaft and try to feed raw materials from it, it will jump from the raw material feed tube into the space in the center of the left and right disks, and the other disk will be attached and rotate at high speed. Some of the raw material that hits the end face of the shaft that is rotating and is thrown away and returns to the inner wall of the end where the disc of the hollow shaft that is rotating at high speed is attached and the end of the raw material feed pipe. and the outer circumference of the hollow shaft, and is deposited on the inner wall of the end of the hollow shaft by centrifugal force.

As the deposits rotating at high speed with this hollow shaft increase in thickness and come into contact with the outer periphery of the raw material feed pipe, they melt due to frictional heat and flow out, fusing to the blades of the left and right discs and stopping the crushing action. This is because it ends up being closed. The present invention comprises a plurality of centrifugal blower blades or is characterized by providing an axial flow blower blade to overcome the above-mentioned difficulties.

The blades that rotate at high speed together with the hollow shaft will repel any material in the raw material that is flying around in the center space of the left and right discs even if it comes to these blades. Since outside air is taken in between the blades and the left and right discs and discharged between the left and right discs, fine powder in the raw materials is not allowed to enter the gap between the blades and the raw material feed pipe.

According to the present invention, it is possible to completely prevent the raw material from jumping between the inner wall of the hollow shaft and the raw material feed pipe with the blades having such a simple structure, and to transfer the raw material between the disks rotating in opposite directions. Enables continuous mooring.

This makes it possible to obtain very fine pulverized material by rotating the left and right disks in opposite directions, and since these disks can be rotated at high speed, the size and weight of the machine are significantly reduced. It is possible to provide a disc-type pulverizer for thermoplastic synthetic resins having a large crushing capacity. The present invention can be used not only for pulverizing thermoplastic synthetic resins but also for pulverizing synthetic rubbers and the like.

The embodiments shown in FIGS. 1 and 2 will be described.

A disk 2 with a number of radial blades 1 is attached to a hollow shaft 4 with bolts 3. The hollow shaft 4 is supported by bearings 7 and 8 inside a bearing box 6 fixed to a casing 5, and is rotated around the center line A-A by a V-bell opening 0 hung on a V-pulley 9 attached to the end. is rotated at high speed. A large number of centrifugal blower blades 11 are provided at the end of the hollow shaft 4 to which the disk 2 is attached. A raw material feed pipe 14 is inserted into the hollow portion of the hollow shaft 4, which is centered on the center line A-A, is fixed to the casing 5 with an arm fitting 12, and has a raw material supply chute 13 at one end. A shroud 16 is installed between the stage provided on the outer periphery of the other end of the raw material feed pipe and the retaining ring 15 so as to leave a slight gap between it and the centrifugal blower blade 11. A disk 18 with a number of radial blades 17 is attached to the shaft 20 with bolts 19.

The shaft 20 is supported by a bearing inside a bearing box 22 attached to the door 21 of the casing 5, and is moved along the center line A-A by a V-belt 24 hung on a V-pulley 23 attached to the end.
The hollow shaft 14 is rotated at high speed in a direction opposite to the hollow shaft 14. The casing 5 is provided with an air population 25 and an outlet pipe 26 for the mixture of ground material and air.

A duct, a cyclone, and an exhaust fan (not shown) are connected to the outlet pipe 26. Due to the high speed rotation of the large number of radial blades 1 and 17 around the center line A-A, the air between the discs 2 and 18 is evacuated through the gaps on the outer periphery of these discs 2 and 18, and new air is introduced. Raw material supply chute 13, raw material sending pipe 1
4 and flows between the discs 2 and 18.

The powdered raw material supplied to the raw material supply chute 13 passes through the raw material feed pipe i due to this air flow and is transferred to the shaft 2 which is rotating at high speed.
The blade collides with the end face of the blade 0 and is blown away, flying around in the space between the discs 2 and 18, and is then sent between the blades 1 and 17 and subjected to a cutting action. The fine powder generated by cutting is cut into a large number of blades 1.
The disk 2 inside the casing 5 is quickly passed through the valley between the blades 17 by centrifugal force, and is drawn into the machine from the air mass 25 by the exhaust fan outside the machine. 18
The air circulates through the space surrounding the outer periphery of the air, is carried while being cooled by the air flowing out from the outlet pipe 26, passes through the duct, and is separated from the air by a cyclone. Some of the fine particles in the raw material flying between the disks 2 and 8 collide with the centrifugal blower blades 11, but since the many centrifugal blowers 11 are rotating at high speed, they are repelled and hit the hollow shaft. It is not possible to penetrate into the interior of 4.

The diameter of the hollow shaft 4 is larger than that of the shaft 20, so that the bearing 7
, 8 are large and the temperature rise due to high speed rotation becomes large. Due to the heat transfer from the bearings 7 and 8, the temperature of the hollow shaft 4 also increases, making it easy for fine raw material powder to fuse to the surface of the end where the disc 2 is attached. Wings 11
Due to the high speed rotation of , outside air flows between the hollow shaft 4 and the raw material feed pipe 14 and between the disks 2 and 18, cooling the hollow shaft 4 and lowering the temperature, and the fine powder is fused to the surface of the above-mentioned part. It is also prevented that Another embodiment shown in FIG. 3 will be explained.

In this embodiment, instead of the centrifugal blower blade 11 shown in FIG.
It is equipped with a large number of axial flow blower blades 27 which have an inclined surface relative to A and have a slight clearance from the outer periphery of the end of the raw material feed pipe 14.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of an embodiment of the present invention, FIG. 2 is a side view of FIG. 1, and FIG. 3 is a partial vertical sectional view of another embodiment. 1...Blade, 2...Disc, 4...
・Hollow shaft, 11...Centrifugal blower blade, 13...
...Raw material supply chute, 14. ．． ．． ...raw material feed pipe,
17...Blade, 18...Disc, 22...
...Bearing box, 27...Axial blower blade.

Claims (1)

[Claims] 1. Two disks facing each other with a small gap and rotating at high speed in opposite directions on a common center line A-A @2@, @
A large number of blades 1 and 17 are arranged in the radial direction on the annular portions near the outer peripheries of opposing circular surfaces of 18@, respectively, and the cutting edge of blade 1 of one disc @2@ and the other disc @18@ In a disc type crusher, the gap between the cutting edge of the blade 17 in the direction parallel to the center line A-A becomes narrower toward the outer periphery of the disc @2 @, @18 @. , attached to the inner surface of the end to which one disk @2@ of the hollow shaft @4 @ rotating around the center line A-A is inserted, and inserted into the center of this hollow shaft 4. There is a slight gap between the tip of the raw material feed pipe 14, the edge on the air outlet side touches the space between the disk @2@ and the disk @18@, and the edge on the air inlet side touches the space between the disk @2@ and the disk @18@. A disc-type fine pulverizer for pulverizing synthetic resins, characterized in that it has a large number of blower blades whose edges are in contact with the elongated annular space between the inner diameter of the hollow shaft @4@ and the outer diameter of the raw material feed pipe 14. 2. The disk-type fine pulverizer for crushing synthetic resins according to claim 1, wherein the large number of blower blades attached to the inner surface of the end of the hollow shaft @4@ are centrifugal blower blades 11. 3. A disk-type fine pulverizer for pulverizing synthetic resin according to claim 1, characterized in that the large number of blower blades attached to the inner surface of the end of the hollow shaft @4@ are axial flow blower blades 27. .