JPH0460703B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a hammer mill for fine grinding.

[Conventional technology]

Conventionally, as a hammer mill for fine pulverization, there is an impact type horizontal fan function-equipped hammer mill shown in FIG. That is, a plate-shaped crushing hammer 3, a U-shaped crushing hammer 4, and a similarly U-shaped fine crushing hammer 5 are provided in order along the axial direction of the rotating shaft 2 in the casing 1 (each For the shapes of the hammers 3, 4, and 5, refer to the examples below), a coarse crushing zone A, a crushing zone B, and a fine crushing zone C are formed in the casing 1, and the raw material a is introduced from one end of the casing 1, and the raw material a is input from the other end. The structure is such that air is taken in from the air by a fan 6.

This device generates an air flow in the casing 1 by suction, gradually breaks the raw material into pieces with each hammer 3, 4, and 5, and conveys the raw material by the air flow to the desired state through the screen 7. Take out the raw material of particle size to the product storage part D, and store the product B.
is conveyed to the next process by the conveyor 8, and the product b mixed into the intake air of the fan 6 is also captured by the back filter 9 and sent to the conveyor 8.

[Problem to be solved by the invention]

By the way, in this conventional hammer mill, the raw material a reaches the pulverization zone C without being sufficiently crushed and pulverized, and remains in the pulverization zone C, causing clogging of the screen 7 or causing long-term pulverization. Grinding burn occurs due to stagnation. Further, if the raw material a remains, the rotational resistance of the hammer 5 increases, leading to an overload condition, which causes various problems.

For this reason, the above-mentioned conventional technology cannot be used for final grinding of finely ground feed in the material industry, and the process is carried out using a dismembrator. However, this dismembrator has the problem that it is inferior to a hammer mill in terms of grinding efficiency, and conversely, it cannot perform rough grinding.

With the above points in mind, it is an object of the present invention to provide a hammer mill that can perform fine pulverization without causing overload or pulverization burn.

[Means to solve the problem]

In order to solve the above problems, in the present invention, a raw material input port and an air intake port are formed on one side of the casing, a rotating shaft is provided in the center of the casing, and the rotating shaft is connected from the one side to the other side. A coarse crushing hammer and a crushing hammer are sequentially provided facing the side to form a coarse crushing zone and a crushing zone in the casing,
The outer casing of the pulverization zone is expanded over the entire circumference, and a pulverization hammer is provided therein via a support plate fixed to the rotating shaft to form a pulverization zone, and this pulverization zone and the pulverization A first screen for passing the pulverized particles is installed around the entire circumference between the zones, a circulation duct communicating with the raw material input port is opened at the top of the pulverization zone, and a first screen for passing the pulverized particles is provided at the bottom of the pulverization zone. Via the second screen,
It has a structure in which product storage sections in the intake state are arranged in series.

[Effect]

The hammer mill configured in this way is, first of all,
As the rotary shaft is rotated, the hammers in each zone also rotate, creating air flow in their radial directions. At this time, since the pulverization zone and the pulverization zone each have an air outflow section on the outer periphery by a screen and duct opening, the flow in the radial direction becomes a flow that crosses each zone, and this flow is in the same direction as the flow due to intake air. This facilitates air flow within the casing. The air flow also causes the crushing zone to have a lower pressure than the finely crushing zone, causing air to circulate through the duct.

In this state, when the raw material is introduced into the casing from the input port, the raw material is pounded and pulverized by each hammer in each zone and gradually becomes finer particles, while following the air flow. The particles move through each zone, and coarse particles are removed by the first and second screens before reaching the product storage section. At this time,
The coarse particles that have reached the pulverization zone are captured by the second screen and tend to accumulate on its surface, but due to the centrifugal force of the hammer and the circulating flow of the duct, they are sent back to the pulverization zone through the duct and recycled. Shattered. On the other hand, the fine powder passes through the second screen and is hardly recycled.

〔Example〕

As shown in FIGS. 2 and 3, the casing 10
A feeding tube 11 for feed (raw material) a is provided on one side of the casing 10, and a rotating shaft 12 is provided at the center of the casing 10. The casing 10 includes a cylindrical portion 10a forming a coarse crushing zone A, which will be described later, and the portion 10a.
A pulverization zone B, a pulverization zone C, and a product storage section D, which will be described later, are configured in this rectangular box-like portion 10b in order from the center toward the outside. Feed a into the feeding cylinder 11
The input is performed via an on-off valve such as a rotary valve or a butterfly damper. In addition, the input cylinder 1
1 is formed with an air intake port 13 whose ventilation amount can be adjusted. The degree of opening of the air intake port 13 is determined by the amount of air circulation, which will be described later.

A rotating disk 14 is fixed to the tip of the rotating shaft 12, and the air flow rate from the input cylinder 11 into the casing 10 is determined by the gap t between the rotating disk 14 and the casing 10. That is, the rotating disk 14
The larger the diameter, the faster the airflow. Rotating axis 1
A support plate 15 serving as a partition for a coarse crushing zone A and a crushing zone B is fixed in the middle of the casing 10 of No. 2, and a partition plate 1
6 are provided at equal intervals, and between them, strip-shaped coarse crushing hammers 18 are rotatably attached at four equal positions in the circumferential direction through pins 17 to constitute a coarse crushing zone A. When rotated, A crushing hammer 18 flies out toward the casing 10 side by centrifugal force and crushes the fed feed a. A pit P for separating heavy objects such as metals and stones is formed in the lower part of the coarse crushing zone A.

A support plate 19 extending close to the inner surface of the box-shaped portion 10b is fixed to the rear end of the rotating shaft 12 inside the casing 10, and two partition plates 20 are provided between the support plate 19 and the support plate 15. Meanwhile, pin 21
C-shaped crushing hammers 22 are rotatably attached to four equal positions in the circumferential direction to constitute a crushing zone B, and when rotated, the crushing hammers 22
The coarse feed a from the coarse crushing zone A protrudes outward.
to crush. Note that the crushing hammers 22 are arranged side by side on the same pin 21 as shown in FIG.
In addition, since this crushing zone B has a larger width (in the direction of the rotating shaft) and outer diameter (screen diameter to be described later) than the coarse crushing zone A, the hammers 18 and 2
The effect of generating air by 2 is higher in the latter case.
For example, set it to about 1.5 times.

A first screen 2 is provided on the outer periphery of the crushing zone B.
3 is stretched, and the hole diameter of this screen 23 is approximately twice the finished grain diameter. but,
If the hole diameter does not fall within the crushing particle size range of the crushing hammer 22, it should be doubled or more so that it falls within the range.

In the casing 10 on the outside of the screen 23, pins 24 are fixed to eight equal parts of the support plate 19, and as shown in FIG. Hammers 25 are attached in a staggered manner via a partition ring plate 26 and a support ring 26' to form a pulverization zone C. A second screen 27 is stretched around the outer periphery of this crushing zone C, and the inside of the casing 10 outside the screen 27 becomes a product storage section D. The hole diameter of the screen 27 is determined by the finished particle size (product particle size),
Usually, it is 10-20% larger than the particle size.

An opening 28 is formed in the screen 27,
A circulation duct 29 communicates with the charging cylinder 11 from this opening 28 . The diameter of this duct 29 is determined to be approximately one-third of the amount of air flowing within the casing 10. If the amount of circulation increases, the amount of exhaust gas by the fan described later will decrease, and the load on the exhaust treatment equipment will also decrease. Therefore, in the case of feed (raw material) a where the disturbances (temperature, moisture, etc.) caused by the circulation of grinding heat can be ignored, the amount of circulation is increased.

This embodiment is constructed as described above, and as shown in FIG. 1, when the feed a is fed into the casing 10 through the feeding tube 11 by the feeder 30 while being sucked in by the fan F,
The feed a is pounded and pulverized by each hammer 18, 22, 25 in each zone A, B, C, and is gradually pulverized into a fine powder. C is moved, coarse particles are removed by the first and second screens 23 and 27, and the product B is delivered to the storage section D.

During this pulverization action, the coarse particles that have reached the pulverization zone C are captured by the second screen 27 and try to accumulate on its surface, but due to the centrifugal force from the hammer 25 and the circulating flow of the duct 29 (for example, 15 m/s)
As a result, it is sent back to the crushing zone A via the duct 29 and re-pulverized. In other words, since it does not accumulate in one place, there is no overload condition, and the feed a
It is re-pulverized and made into a fine powder without any grinding burn.

The product b that has arrived at the product storage section D is conveyed to the next process by the conveyor 31. Further, the air taken in by the fan F is exhausted through a bag filter 32, and the product b in the air is captured by the bag filter 32 and sent to the conveyor 31.

Note that by appropriately selecting the hole diameter of the second screen 27, the product b can have any diameter. In other words, it can be used for rough grinding to fine grinding.

〔Effect of the invention〕

The present invention is configured as described above, and the coarse powder is circulated and re-pulverized, so that fine pulverization can be carried out without overloading or causing pulverization burn.

Further, since the fine grinding zone is provided on the outer periphery of the grinding zone, the air flow can be promoted by the hammer in that zone, and the load on the intake fan can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic operational diagram of an embodiment of a hammer mill according to the present invention, FIG. 2 is a cutaway front view of the same embodiment, FIG. 3 is a left side view of FIG. 2, and FIG. FIG. 5 is a perspective view of the main part of the pulverization zone shown in FIG. 2, FIG. 5 is a perspective view of the main part of the pulverization zone of FIG. 2, and FIG. 10...Casing, 11...Charging tube, 12...
...Rotating shaft, 13...Air intake port, 14...Rotating disk, 18...Crushing hammer, 22...Crushing hammer, 23...First screen, 25...Fine grinding hammer, 27...Second Screen, 29...Circulation duct, A...Crushing zone, B...Crushing zone,
D...Product storage section, F...Fan, a...Feed (raw material), b...Product.

Claims (1)

[Claims] 1 A raw material inlet and an air intake are formed on one side of the casing, a rotating shaft is provided in the center of the casing, and a crushing hammer and a crushing hammer are sequentially installed on this rotating shaft from one side to the other. to form a coarse crushing zone and a crushing zone in the casing,
The outer casing of the pulverization zone is expanded over the entire circumference, and a pulverization hammer is provided therein via a support plate fixed to the rotating shaft to form a pulverization zone, and this pulverization zone and the pulverization A first screen for passing the pulverized particles is installed around the entire circumference between the zones, a circulation duct communicating with the raw material input port is opened at the top of the pulverization zone, and a first screen for passing the pulverized particles is provided at the bottom of the pulverization zone. Via the second screen,
A hammer mill consisting of a series of product storage sections in the intake state.