JPH0443706B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a casing that forms a grinding chamber, a nozzle that injects a jet air stream to a material to be ground inside the casing, and a nozzle that takes out fine powder in the grinding chamber by air conveyance. This invention relates to a jet mill equipped with a recovery path.

[Conventional technology]

Conventionally, as shown in FIG. 9, a material to be crushed is introduced into a fixed casing 25 from a supply path 26, and a nozzle 28 for injecting a jet air stream onto the material to be crushed 27 in the casing 25 is provided at the bottom of the casing 25. The structure was such that the fine powder pulverized and blown up by the impact of the jet airflow was taken out from the collection path 29 by airflow conveyance (for example, in
(See Publication No. 13049).

[Problem that the invention seeks to solve]

However, the concave portion 31 formed in the material to be crushed 27 in the casing 25 by the jet airflow
7 is fixed only by gravity and is easy to move, so it tends to become deep, and there is a great risk that the impact force due to the jet airflow will be strongly applied to the bottom of the casing 25, and the casing 25 is easily damaged.

In addition, the materials 27 to be crushed that are not sufficiently finely blown up by the jet air flow tend to flow into the recovery path 29, increasing the amount of coarse powder returned from the return path 32 into the casing 25. However, the drawback was that the grinding efficiency was low.

It is an object of the present invention to effectively suppress damage to the casing due to jet air flow and the inflow of coarse powder into the recovery path at once.

[Means for solving problems]

A characteristic configuration of the present invention is that a casing forming a crushing chamber is rotatably attached, and a drive device is provided for rotating the casing at high speed so that the material to be crushed inside the casing is pressed against the inner peripheral surface of the casing by centrifugal force. The nozzle for injecting a jet air stream onto the material to be crushed inside the casing is attached toward the inner circumferential surface of the casing, and its effects are as follows.

[Effect]

In other words, the casing is driven to rotate at high speed,
The material to be crushed is strongly pressed against the inner circumferential surface of the casing by centrifugal force, and the jet airflow from the nozzle is injected onto the material to be crushed which is fixed to the inner circumferential surface of the casing due to the strong centrifugal force. The concavity formed by the jet air flow in the layer of material to be crushed that is pressed against the pulverized material layer can be maintained shallow enough to prevent the impact force caused by the jet air flow from being too strongly applied to the casing. To explain further, the less crushed the material is, the more centrifugal force presses against it, and it does not move much even when the jet airflow collides with it, and when a recess is formed, the material nearby is stronger. It moves to fill the recess with centrifugal force,
The synergistic effect makes the recess shallower, effectively preventing impact damage to the casing due to jet airflow.

In addition, due to centrifugal force, the larger the material to be crushed, the harder it is to scatter, and the finer the material, the easier it is to scatter, so the inconvenient phenomenon of coarse powder being transported by air current to the collection path connected to the casing is effectively eliminated. Furthermore, since the jet airflow collides with the material to be crushed which is strongly fixed to the inner circumferential surface of the casing by centrifugal force, the energy of the jet airflow is efficiently used for crushing, and the synergistic effect of the jet airflow allows for efficient crushing.

〔Effect of the invention〕

As a result, it has become possible to provide a jet mill that can sufficiently prevent damage to the casing due to jet airflow, can efficiently perform pulverization, and has even better durability and pulverization performance.

〔Example〕

Next, an embodiment will be explained with reference to FIGS. 1 to 3.

A vertically oriented first rotary cylinder shaft 2 attached to a base 1
A disk-shaped casing 4 forming a crushing chamber 3 is attached concentrically to the upper end, and a drive device 5 consisting of an electric motor 5a, a transmission 5b, etc. is linked to the lower end of the first rotary cylinder shaft 2, and the casing 4, the material to be crushed inside the casing inner peripheral surface 4 due to centrifugal force.
configured to be driven and rotated so as to be pressed against a,
Moreover, the rotation speed of the casing 4 is configured to be adjustable so that an appropriate centrifugal force can be obtained depending on the properties of the material to be crushed.

The second rotary cylinder shaft 6 attached to the base 1 is
A plurality of nozzles 7 are attached to the upper end of the second rotary cylinder shaft 6 so as to face the inner peripheral surface 4a of the casing, and a high pressure gas supply device 8 is installed on the second rotary cylinder shaft 6 so as to extend concentrically through the rotary cylinder shaft 2. The second rotary cylinder shaft 6 is connected to the rotary joint 9 attached to the lower end of the second rotation cylinder shaft 6.
The high-pressure gas supplied from the jet airflow is injected from the nozzle 7 onto the material to be crushed on the inner circumferential surface 4a of the casing, and the material fixed to the inner circumferential surface 4a of the casing by centrifugal force is pulverized by the impact force of the jet airflow. It is configured to process.

Attach an accelerator tube 10 concentrically to each nozzle 7,
The end of the acceleration tube 10 on the nozzle 7 side is formed so that the diameter becomes larger toward the nozzle 7, and the gas and coarse powder in the casing 4 are sucked into the acceleration tube 10 by the jet airflow from the nozzle 7, and a large amount rectify and accelerate the gas of
It is constructed so that a large impact force can be applied to the material to be crushed.

A drive device 12 consisting of an electric motor 12a, a transmission 12b, etc. is linked to the lower end of the second rotary cylinder shaft 6, and the nozzle 7 and the acceleration tube 10 are connected to the inner peripheral surface 4 of the casing.
It is configured to be driven and rotated in the same direction around the same rotational axis and with a small relative speed difference with respect to a, and is configured to be able to apply an impact by the jet air flow to the entire material to be crushed. Generally, the rotation speed of the casing 4 is 1500 to 4000 rpm when its diameter is 200 mm, and the rotation speed of the nozzle 7 is slower or faster by several rpm to several tens of rpm. Also, when the diameter of the nozzle 7 is 2 mm, the jet air flow is applied at a pressure of 5 to 8 kg/cm ^2.
Spray at a rate of 200 to 400/min.

An opening 13 is formed in the center of the upper part of the casing 4 for supplying the material to be crushed from the raw material supply device 11 into the casing 4 by falling under its own weight and taking out the crushed material by air conveyance. The suction device A is connected directly to the casing 4.

Case 1 with upwardly expanding shape in suction device A
A tapered conical body 23 attached to a vertical rotating shaft 22 interlockingly connected to an electric motor 21 is attached to the upper part of the interior of the 0.
As shown in FIG. 2, a large number of suction blades 24 are attached to a conical body 23, and a fine powder collection path 14 is connected to the space surrounded by the suction blades 24 to collect ultrafine powder using a bag type or the like. The collector 15 and the exhaust fan 16 are connected to the fine powder collection path 14 in that order, and the coarse powder is returned to the casing 4 by falling under its own weight, and the average
The collector 15 is configured to collect ultrafine powder of ~3 μm or less.

An outer case 17 is provided that surrounds the casing 4 and the case 20 of the suction device A, and the blower 1 is installed inside the outer case 17.
8 are connected by a flow path 30 with a variable throttle, and the casing 4
The structure is such that powder does not flow out from between the casing 4 and the case 20, and the casing 4 can be cooled by air circulation generated by the rotation of the casing 4 and the action of the guide plate 19.

[Another example]

Next, another embodiment will be described.

The shape of the inner peripheral surface of the casing 4 can be changed appropriately.
For example, as shown in FIG. 4, a plurality of upper and lower crushing chambers 3 are formed around the inside of the casing 4, and a nozzle 7 is installed to inject a jet air stream into each of the crushing chambers 3.
As shown in FIGS. 5 and 6, a large number of crushing chambers 3 may be arranged in parallel in the circumferential direction inside the casing 4, and each of the crushing chambers 3 may be arranged in parallel in the direction of the rotation axis. The nozzle 7 may be attached to rotate integrally with the casing 4, and the grinding chambers 3 arranged in the circumferential direction may be formed into a spherical shape, as shown in FIGS. 7 and 8. The crushing chambers 3 may be arranged vertically and circumferentially.

The number of nozzles 7 installed can be freely changed, and the nozzles 7 may be integrally or separately connected to the casing 4 and driven at a constant speed, or may be fixed. Further, the gas supplied to the nozzle 7 can be appropriately selected depending on the material of the material to be crushed.

As shown in FIGS. 5 to 8, the dividing suction blade 2
4 may be provided within the casing 4, or the suction device A may be separate from the jet mill.

As shown in FIGS. 6 and 8, the raw material supply device 11 may be provided so as to directly communicate with the casing 4, and the raw materials may be heat-sensitive organic substances, metal oxides, easily hardened objects, or crushed materials. The necessary aggregates are suitable, but various other raw materials can be used.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

1 to 3 show embodiments of the present invention,
FIG. 1 is an overall conceptual diagram, FIG. 2 is a cross-sectional view taken along the line -- in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line - FIG.
4 to 8 show another embodiment of the present invention,
Fig. 4 is a sectional view of the main part of the first alternative embodiment, Fig. 5 is a sectional view of the main part of the second alternative embodiment, and Fig. 6 is a sectional view of the main part of the second alternative embodiment.
A line arrow view, FIG. 7 is a sectional view of the main part of the third alternative embodiment,
FIG. 8 is a view taken along the - line in FIG. 7. FIG. 9 is a sectional view of a conventional example. 3...Crushing chamber, 4...Casing, 4a...Inner peripheral surface of casing, 5...Drive device, 7...Nozzle, 14...Recovery path.

Claims (1)

[Scope of Claims] 1. A casing 4 forming a crushing chamber 3, a nozzle 7 for injecting jet airflow onto the material to be crushed within the casing 4, and a recovery path 14 for taking out the fine powder in the crushing chamber 3 by air flow conveyance. It is a jet mill,
The casing 4 is rotatably mounted, and a drive device 5 is provided which rotates the casing 4 at high speed so that the material to be crushed inside the casing 4 is pressed against the inner peripheral surface 4a of the casing by centrifugal force, and the nozzle 7 is connected to the inner peripheral surface of the casing. A jet mill installed facing surface 4a. 2. The jet mill according to claim 1, wherein the nozzle 7 is mounted to the casing 4 so as to be freely driven and rotatable in the circumferential direction around the same rotational axis with a small relative speed difference. 3. The jet mill according to claim 1, wherein the nozzle 7 is mounted to the casing 4 so as to be freely driven and rotatable in the circumferential direction around the same rotational axis at a constant speed.