JPS6082150A - Impeller mill - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an impeller mill having a casing consisting of an upper part and a lower part and constituting a cutting chamber. The present invention relates to a type in which the cutting rotor cooperating with the sieve limiting below is supported horizontally in the casing.

Prior art in-wave mills are used to break cuttable feed materials produced in small pieces into granules, which granules are obtained as a mass with a relatively narrow particle size range. The cutting rotor of this type of impeller mill is equipped with a beam-shaped cutter, and the cutting rotor is usually 10-15 m/
It passes by a fixed cutter and a sieve in the casing at a circumferential speed of S. The material to be ground is subjected to centrifugal action in the cutting chamber until it passes through the sieve and leaves the cutting chamber, and is continuously ground. These impeller mills are very noisy due to the acoustics generated due to the relatively high cutting speeds, as well as the impact and crushing sounds, and therefore require effective and therefore expensive soundproofing equipment.

Additionally, in order to prevent granules and partially crushed material from flying out of the cutting chamber as a result of the high circumferential speed of the cutting rotor, a jet curtain, a jet lock dart or a flat rod is provided. , a relatively high, curved structure feed/neat is required. However, the result of this is that the charging of bulky but lightweight materials is prevented, or at least difficult.

It is thought that the above-mentioned drawbacks can be sufficiently eliminated by significantly reducing the circumferential speed or cutting speed, but with a cutting rotor of the conventional structure, the cutting frequency obtained at that time is too small. , relatively possible milling efficiency is not achieved.

Moreover, if the cutter blades are arranged parallel to the axis, even when shearing with the cutter blades slightly inclined relative to each other, an extremely large driving force is required due to the large cutting length. Dew. This is because no energy is stored due to the momentum of the cutting rotor.

The object of the invention is to find a mill in which the important drawbacks of the known constructions, namely noise generation and material ejection, are largely avoided, and yet an economical grinding efficiency is obtained.

As a solution, starting from an impeller mill according to the tortoise concept according to claim 1, the cutting rotor is constructed as a one-piece flat milling cutter with threaded cutting edges, as used in the metalworking field. , and is driven by a gear motor directly connected to this li+J cutting rotor to give the threaded cutting blade a circumferential speed of 0.5 to 3 m/s. In this case: The lead angle of the threaded cutting edge is 70~
85°, and the pitch of the threaded cutting edge is 20 to 100
It is advantageous to shout.

Slowly rotating strand or strip pulverizers with generally straight cutting edges are known, but this is based on another problem.

In other words, the task is not to crush a mass of material to be crushed in a cutting chamber limited by a sieve, but rather to cut a cylindrical strand into pieces of uniform size with a Strynozo machine fed mechanically at a constant speed. It is to be. In an impeller mill, the material to be crushed is supplied to the cutting blades mainly by gravity.

This requires that the cutting rotor be constructed as described above.

Effects of the Invention The impeller mill constructed in accordance with the present invention achieves the same throughput as that of an ordinary impeller mill of relatively possible dimensions, despite the small circumferential speed of the cutting rotor, and with less noise generation and Materials now fully avoid flying out. This is made possible by the cooperation of the features of claims 2 to 8: The use of a flat milling cutter, which is used in the metalworking field, as a cutting rotor is a manufacturing device and a method as well as a This is particularly advantageous since grinding equipment already exists and prices are relatively low due to strong competition.

Due to the low circumferential speed, the pitch of the cutting rotor's cutting blades, which is typically around 300 m, can be kept extremely small, even though the material has sufficient time to fall into the gap between the cutting blades to be cut. have. A small pitch results in a high cutting frequency and thus a high grinding efficiency. Due to the direct connection between the cutting rotor and the gear motor, the insufficient momentum of the cutting rotor due to the low circumferential speed is transferred to the motor through a rigid two-way transmission, unlike the conventional V-belt transmission. enhanced by Therefore, a motor with a relatively small drive output is sufficient.

The threaded cutting edge provides a uniform motor load without significant peak loads. In this case, by arranging the cutting blades in a double-sided pattern, the material circulating in the cutting chamber is fed primarily to the center of the cutting rotor, thereby reducing the phase load on the end faces of the rotor, and in particular for thermoplastic materials. In this case, the side wall of the casing is prevented from becoming contaminated with oil and fat.

Furthermore, a removal strip provided on the end face of the cutting rotor also assists in this case. The removal strip optionally cooperates with the removal strip of the side wall and effectively prevents, inter alia, lint and sheet strips from wrapping around the rotor shaft.

Compared to metalworking, the small cutting forces make it possible to form a relatively large cutting groove in front of the cutting edge, which leads to an improved material receiving capacity.

Moreover, by forming the blade grooves to be large, the flow cross section for sucking the cooling air also becomes large. In practice, a configuration in which the depth of the blade groove is approximately equal to the cutting blade pitch has been proven to be superior.

The kinetic energy of the granules circulating in the cutting chamber may not be sufficient to pass through the sieve due to the relatively low circumferential speed of the cutting rotor, so in that case the kinetic energy of the granules circulating in the cutting chamber is not sufficient to pass through the sieve. It is advantageous to size the distance of the sieve in such a way that the granule particles can be mechanically forced through the sieve holes by the cutting blades. In this case, the sieve pore diameter is IY
'A distance equal to A has been proven to be superior.

The inner mill according to the invention is particularly suitable for construction as a machine located below an injection molding machine for plastic processing. This is because the cost and structural height required to prevent the flying out of the material are high, so a configuration with a short throw/yaft and a Y-shaped suction tank is possible. This is because. In that case, there is no need to take any preemptive measures against intrusion into the impeller mill. This is because the injection molding machine and its appropriately configured safety devices prevent this.

Actual Addition/F Row Next, one embodiment of an impeller mill constructed according to the present invention will be described. The casing of the impeller mill also consists of a lower part 1 and an upper part 2 and side walls 3 fixed to their end faces.

The housing forms a cutting chamber in which a cutting rotor 4 is supported horizontally and cooperates with a cutter 5 fixedly arranged in the housing. The cutting chamber is delimited at the bottom by a sieve 6. The cutting rotor 4, which is designed as a flat milling cutter, has a threaded cutting edge 7, which is designed in the form of a dovetail. The shaft 8 of the cutting rotor 4 is directly connected to a gear motor 10 by a coupling 9.

The cutting rotor 4 is equipped on its end face with a removal strip 11, which serves to feed the material that has entered between the cutting rotor shaft and the side wall 3 back into the area of the cutting rotor.

The material to be ground is fed to the impeller mill via the input shaft 12 and, after being ground and passed through the holes in the sieve 6, is pneumatically removed through the suction tank 13. The circumferential speed and configuration of the cutting rotor 4 correspond to the values set forth in the claims. The in-R mill, which has a low structure in this way, is mounted on a movable base plate 14 together with its drive unit, and is used to crush sprue and defective products produced in the injection molding machine. This machine is placed below the injection molding machine for plastic processing. The resulting pulverized granules can then be immediately fed back into the injection molding process.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional side view of an embodiment of an in-cover mill according to the invention, and FIG. 2 is a cross-sectional view according to the arrows in FIG. ■...lower part, 2...upper part, 3...side wall, 4...cutting rotor, 5...fixed cutter, 6...sieve, 7...cutting blade, 8...i! II, 9...Joint, 10...Gear motor, 11...Removal strip, 12...Drop 7 Yaft,
13. Inhale (1 other person)

Claims (1)

[Claims] 1. An insular mill having a casing consisting of an upper part and a lower part and constituting a cutting chamber, which cooperates with a cutter fixedly arranged in the casing and a sieve that limits the cutting chamber below. in which the working cutting rotor is supported horizontally in the casing, said cutting rotor (4) being constructed as an integral flat milling cutter with a threaded cutting edge (7) as used in the metalworking field; and is driven by a gear motor (10) directly connected to the cutting rotor (4) to give the threaded cutting blade (7) a circumferential speed of 0.5 to 3 m/S. 2. The in-four mill mill according to claim 1, wherein the threaded cutting blade (7) has a lead angle of 70 to 8 degrees. 3. The impeller mill according to claim 1 or 2, wherein the screw-shaped cutting blade (7) has a tightness of 20 to 100 mm. 4. The screw-shaped cutting blade (7) is formed in the form of a double sided corner which co-operates with the stationary cutter (5) and feeds the pulverized material into the central part of the cutting rotor (4). The in-cover mill according to any one of paragraphs 3 to 3. 5. The impeller mill according to any one of claims 1 to 5, wherein the depth of the blade groove in front of the threaded cutting blade (7) is approximately equal to the cutting blade pitch. 6. In-cover mill according to one of the claims 1 to 5, characterized in that a removal strip (11) is arranged on the end face of the cutting rotor (4). 7. The in-lar mill according to any one of claims 1 to 6, wherein the distance of the sieve (6) from the outer peripheral surface of the cutting rotor (4) is approximately equal to the pore diameter of the sieve. . 8. Any one of claims 1 to 7, which is configured as a machine with a low-throw shaft and a flat suction tank and arranged below an injection molding machine for plastic processing. Impeller mill listed.