JPH01228535A - Method and apparatus for applying coating material to surface of grain - Google Patents

Abstract

PURPOSE:To enable efficient application of a coating material to surfaces of grains by fluidizing the grains with an apparatus consisting of a plurality of small diameter cylinders and large diameter ones piled up one after another and by introducing a coating material into a fluidized bed of the grains. CONSTITUTION:An apparatus, which consists of a plurality of large diameter cylinders 1-5 and small diameter ones 6-12 plied up vertically one after another, is employed. For example, grains supplied by means of a grain feeder 11 are sent to a bottom cylindrical part by nitrogen from a blower 13 and an action of an ejector 16 and transferred upward sequentially from one cylindrical part to another one while being fluidized in each cylindrical part. An oil is atomized into the fluidized grains through a nozzle 22 and made to adhere to the surface of each grain. Next, powder is introduced through a supply port 28 and made to adhere to the surface of each oil-covered grain by a fluidizing action. The grains coated evenly with the powder are sequentially and continuously discharged out of a discharge port 29 into a product tank 30.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method and apparatus for dusting the surfaces of many granules with powder made of fine particles.

[Prior Art] Conventionally, it has sometimes been necessary to evenly sprinkle powder on the surface of a beret made of, for example, resin.

That is, when sending pellets, which are granules, it is necessary to send them smoothly in a laminar flow, and when feeding the pellets into a barrel, it is necessary to make the pellets slip easily.

Or, as in the case of injection molding using pellets,
It is necessary to mix the raw materials of different ingredients evenly to ensure consistent quality.

In such cases, the powder is evenly sprinkled on each surface of the pellet.

By the way, conventionally, when applying powder evenly to each surface of pellets, a predetermined amount of pellets and powder are placed in a container called a blender and rotated slowly for a predetermined amount of time to ensure that the powder adheres to the granules. was done in batch mode.

[Problems to be Solved by the Present Invention] Conventionally, when powder is sprinkled on the surface of granules, it has been done in a batch manner using a blender, so a relatively large amount of granules and ( By inserting the rudder and doing this while slowly rotating the tank,
The time required for one treatment is extremely long, such as 4 to 5 hours, and is inefficient. In addition, since the tank is large, the entire Brenta is large, and the installation area of the device is large, occupying a large space. Of course, do it in batch mode.
,X, so the operation was very troublesome.

Also, since conventionally it was done in batch mode, 1. < Sprinkling with the ladder had to be done in a separate operation from transporting the granules, which was also inefficient, and it was difficult to adjust the degree of powder sprinkling and the amount of powder to be processed. It was very difficult.

[Means for Solving the Problems] In order to solve the above-mentioned conventional problems, the present invention sprinkles powder on a single grain during transportation to a product tank, etc., and furthermore, continuously performs the following steps: It is designed to be efficient and efficient.

To this end, the present invention uses a device in which a plurality of large-diameter cylindrical parts and small-diameter cylindrical parts are sequentially and alternately stacked on the same axis, and particles and gas are introduced from the bottom of the cylindrical parts. Using a method of fluidizing the particles in the cylindrical part and moving them upward one by one and discharging the granules from above, the liquid is sprinkled into the group of fluidized particles in the cylindrical part, and then By sprinkling powder into a group of granules sprinkled with liquid, the powder was evenly spread over the surface of the granules.

In addition, as a device for this purpose, a device is installed in which multiple large-diameter cylindrical portions and small-diameter cylindrical portions are sequentially and alternately stacked on the same axis, and the gas and particles are placed at the lower end of the lowest cylindrical portion. A liquid inlet is provided in the lower cylindrical part, a balata inlet is provided above the liquid inlet, and an outlet for granules whose surface is coated with powder is provided in the uppermost cylindrical part. The device has a structure that includes

On the other hand, a method of countercurrently introducing gas from the bottom of the cylindrical part and granules from the top of the cylindrical part to sprinkle powder on the surface of the granules involves the use of multiple large-diameter cylindrical parts and A device is installed in which small-diameter cylindrical sections are stacked one after another on the same axis, with a gas inlet at the bottom, a granule inlet at the top, a liquid introduction section above the middle, and a powder introduction section below the middle. A separate section was installed to serve as a device for sprinkling the powder onto the surface of the granules.

[Effect] When a large number of particles are blown in with gas from below the large-diameter cylindrical part at the bottom, the flow rate of the gas decreases as it moves from the small-diameter part to the large-diameter part, and the particles are blown up by that amount. Power decreases. In this case, most of the particles are blown up near the solid axis of the large-diameter cylindrical part, and then lose their upward force near the two ends of the large-diameter cylindrical part. It moves toward the outside of the cylindrical part and falls along the inner peripheral surface of the large-diameter cylindrical part. When the fallen particles reach the lower inlet, they pass through the vicinity of the solid axis of the large-diameter cylindrical part and rise again due to the blow-up blade of the gas from below. In this way, the particles continue to circulate within the large diameter tube.

In that case, by adjusting the flow rate of the blown gas, some of the particles in the large-diameter cylindrical part remain fluffy in the small-diameter cylindrical part above, while the particles in the large-diameter part immediately above The particles enter the cylindrical part, and while repeating the interlocking action described above, gradually move upward. At this time, the particles move upward to the large diameter cylindrical part. The amount is appropriately adjusted depending on the amount of granules supplied and the flow rate of the gas to be blown up.

In this way, when the particles are flowing and circulating in the large diameter cylindrical part, a liquid, preferably oil, is first introduced into the group of particles, and then a powder is easily attached to the particle group. Sprinkle liquid on the surface of each grain.

In this case, since the granules are fluidized, the liquid adheres evenly to the surface of the granules.

After that, if powder is introduced in the same way, the powder will easily adhere to the surface of each granule to which liquid is attached, and as the granules continue to rise while fluidizing, the powder will be deposited on the surface of the granules. Sprinkle evenly.

In this way, the powder-covered granules rise and are taken out by overflow from the uppermost large-diameter cylindrical section.

When applying powder evenly, there are cases in which only powder is applied without using liquid.

On the other hand, in a method in which gas is introduced countercurrently from the bottom of the cylindrical part and particles are introduced from the top of the cylindrical part, the same fluidization can be achieved by adjusting the gas flow rate, and the powder can be It can be discharged from the bottom while dispersing the particles evenly.

[Example] In an embodiment of the present invention shown in FIG. 1, 1 to 5 are large diameter cylindrical parts, 6 to 10 are small diameter cylindrical parts, and a plurality of large diameter cylindrical parts The cylindrical parts 1 to 5 and the small diameter cylindrical parts 6 to 10 are sequentially and alternately stacked on the same axis. Large diameter cylindrical parts 1 to 5
are the truncated conical tubular portions 1a to 1a facing downward, respectively.
5a, the cylindrical parts 1b to 5b, and the truncated conical cylindrical parts lc to 4C facing upward are stacked one after another from bottom to top, and each of the upper and lower truncated conical cylindrical parts Part 1a
Each of the truncated parts of ~5a and lc~4c is connected to a lower small-diameter cylindrical part 6-10 and an upper small-diameter cylindrical part 7-10, respectively. However, in this embodiment, the upper truncated conical cylindrical part 5C is not necessarily provided in the large diameter cylindrical part 5 at the top stage. 1 to 5 and small-diameter cylindrical portions 6 to 10 are provided in five stages in Fig. 1, but depending on the usage conditions, the number can be selected as appropriate, such as three to six stages. be able to. The diameters of the large-diameter and small-diameter cylindrical parts 1 to 5.6 to 10 vary depending on the amount of granules to be processed, but are, for example, 10 to 5.
They were about 0 to 300 mm and 30 to 100 mm. Also,
The angle of inclination of the lower truncated conical tubular portions 1a to 5a is set to be smaller than the angle of repose of the granules in order to retain the granules for as long as possible.
For example, the angle of inclination of the upper truncated conical cylindrical portions 1c to 4C is set to be relatively gentle, such as increased by 1 to 10 degrees.
The slope was relatively steep so that the particles could easily move upward.

11 is a supply device for granules, which are pellets that are intended to sprinkle powder on the surface; 12 is a rotary valve that can change the rotation speed; 13 is a blower that sends gas such as air or nitrogen gas; and 14 is a flow rate adjustment valve. The tip of the gas conduit 15 extending from the flow regulating valve 14 is disposed in the ejector 16 for powder transfer below the rotary valve 12, and the gas conduit 15 extending from the ejector 16 and the powder transfer Introductory tube 17
The distal end portion of is integrated with the lowermost small-diameter cylindrical portion 6. Incidentally, in FIG. 1, 18 parts are shown as the inlet for gas and particles. Note that the pressure of the blower 13 can be adjusted.

19 is a supply device for a liquid having a viscosity such as oil;
20 is a flow rate adjustment device, 21 is a liquid introduction pipe, and 22 is a nozzle for spraying liquid provided near the solid axis in the large diameter cylindrical portion l at the lowermost stage. The liquid introduction pipe 21 and the nozzle 22 can be provided within the cylindrical portion lb as shown, or may be provided within the lower truncated conical cylindrical portion la.

23 is a supply device for powder to be sprinkled on the surface of the granules, 24 is an on-off valve, 25 is a compressor for supplying air for powder transfer, 26 is an ejector, and 27 is a powder supply pipe. It was introduced near the solid axial line part in the large diameter cylindrical part 2 of the step. 28 is a powder supply port at the tip of the powder supply pipe 27. Incidentally, since the powder supply pipe 27 may be provided above the liquid introduction pipe 21, the powder supply pipe 27 may be led into the large diameter cylindrical portion l at the lowermost stage.

Although the nozzle 22 of the liquid introduction pipe 21 and the opening of the powder supply port 28 are shown facing downward in the state shown in Figure 1,
In order to efficiently sprinkle the powder on the granules, this may be done horizontally, or in another direction such as diagonally downward, and of course, in multiple directions at once. It can also be made to be able to squirt liquid or powder. Also,
It is also possible to eject the liquid near the inner circumferential surface instead of near the solid axis.

A discharge port 29 was provided on the side surface of the uppermost cylindrical portion 5 to discharge the granules whose surface was sprinkled with powder by overflowing them. 30 is a product tank or bag for storing granules whose surface is coated with powder.

31 is a gas discharge pipe connected to the top of the large diameter cylindrical part 5 at the top, 32 is a bag filter for collecting a small amount of powder mixed in the exhausted gas, and 33 is a gas discharge pipe from below the bag filter. A container for receiving powder.

The gas discharged from the bag filter 32 is transferred to the gas conduit 34.
The air is guided to the compressor 25 via the blower 13 and the on-off valve 35.

36 is a differential pressure detector connected to the cylindrical part 6 on the inlet side and the cylindrical part 5 on the outlet side through piping 37 and 38, 39 is a differential pressure setting device, and 40 is a differential pressure setting device 39 and a differential pressure detector. It is a comparator that converts the values detected by 36 into electrical signals and compares them, and the output signal of the comparator 40 can be used to adjust the flow rate regulating valve 14 connected to the blower 13, etc. Note that the differential pressure detector 36 may be provided between the other small-diameter cylindrical portions 6 and 8, for example, as shown by the two-dot chain line in FIG.

When applying powder to granules using the device of the present invention,
Do it as follows.

First, the blower 13 is driven to inject nitrogen gas into the cylindrical part 6 and 1 through the particle and gas introduction pipe 17, for example, at a discharge pressure of 0, 01 to 0, 1 Kg/crn'c7) at a gauge pressure.
The granules to be sprinkled with powder are supplied from the granule supply device 11 via the rotary pulp 12 while the granules are being introduced into the resin. A zero particle material using pellets such as the above is sent through the introduction pipe 17 by the action of the nitrogen gas from the blower 13 and the ejector 16.

In this way, the flow velocity of nitrogen gas in the large diameter cylindrical parts 1 to 4 is, for example, 0.5 to 165 m/sec, and the flow velocity of nitrogen gas in the small diameter cylindrical parts 6 to 10 is 1.
For example, the flow rate of nitrogen gas in the large diameter cylindrical parts 1 to 4 is adjusted to 5 to 15 m/sec. The flow rate of the nitrogen gas in the small diameter cylindrical parts 6 to 10 is set such that the particles riding on the air flow continue to float fluffy in the same place. , the flow velocity is set to such a level that the liquid is gradually fed into the upper large-diameter cylindrical parts 1 to 5.

This is because when nitrogen gas, which has been traveling at a relatively high speed in the small-diameter cylindrical part 6, enters the large-diameter cylindrical part 1 with a wide cross-sectional area, the flow rate naturally increases in inverse proportion to the cross-sectional area. If the flow rate of the nitrogen gas in the introduction tube 17 is appropriately adjusted, such a state can be naturally obtained.

The nitrogen gas with a reduced flow rate entering the cylindrical part l from the cylindrical part 6 rises almost vertically near the solid axis of the large diameter cylindrical part l. Gradually raise the grains located near the center. However, this airflow is adjusted to a flow velocity that prevents most of the particles from being sent into the upper small-diameter cylindrical section 7, so most of the particles flow into the upper part of the large-diameter cylindrical section 1. As it goes, the upward force is lost and the particles move outward, and due to the action of gravity acting on the particles, they fall along the inner circumferential surface of the cylindrical part l, and when they fall downwards, they fall into a small diameter cylinder. It rises again riding the strong upward air current rising from the shaped part 6. In this way, most of the particles repeat the flow circulation inside the large-diameter cylindrical part l, for example, by drawing a trajectory as shown by the arrow in the drawing, but only a small part of the particles Riding on the rising airflow of the solid axis, the material is fed into the small diameter cylindrical portion 7 in the upper stage, where it is fed into the large diameter cylindrical portion 2 in the upper stage while continuing to float.

In this way, the particles gradually move upward while being fluidized and circulated by the air current.

In this state, first, the liquid supply device 19 is driven, and oil is sprayed or dropped little by little from the nozzle 22 and introduced into the flowing granules, and each granule is Adhere to the surface. In this case, since the granules are fluidized, they are in a state of rotation (rotation), and the entire surface of each granule is evenly coated with oil. Note that oil may be always supplied in a predetermined amount or may be supplied reciprocally.

Next, the powder supply device 23 and the compressor 25 are operated to fill the fluidized granules in the large-diameter cylindrical portion 2 with one particle consisting of, for example, fine particles of calcium stearate with a diameter of about 8 mm. Introduce powder. Then, due to the fluidization effect, powder adheres to the surface of each granule to which oil is attached. Of course, there may be cases where the powder does not adhere to the entire surface of each particle sufficiently within one cylindrical part 2, so the powder may not be sufficiently attached to the entire surface of each granule, so several large-diameter cylindrical parts 3.
In Step 4, circulate the powder in sequence to evenly coat the entire surface of the grains.

In this way, the granules whose surfaces are evenly coated with powder move into the uppermost large-diameter cylindrical part 5 and are automatically sequentially discharged into the product tank 30 by overflow from the discharge port 29. Ru.

Nitrogen gas discharged from the top of the large-diameter cylindrical portion 5 is guided to the bag filter 32, and is directed to the blower 14 and compressor 2.
5 and used again. By the action of the bag filter 32, a small amount of powder contained in the nitrogen gas is recovered and discharged into the container 33.

Next, a control device equipped to smoothly operate this device will be described below.

First, in order to control the height of the granule layer within each cylindrical body, for example, the differential pressure between two cylindrical bodies is measured, and if it is larger than a predetermined differential pressure, the granule layer height is high. Based on this judgment, the blower's flow rate adjustment valve is opened to increase the flow rate and cause the particles to flow upward. If the differential pressure is lower than the predetermined pressure, it is determined that the granule layer height is low, and the blower's flow rate regulating valve is closed to reduce the flow rate and store the granules.

As a sensor for adjusting the particle layer height, in addition to the differential pressure between two cylindrical bodies, a method of detecting the layer height using an optical switch or the like is also considered.

Second, the amount of powder or liquid supplied is controlled according to the amount of granules supplied.The amount of granules supplied is detected, and the amount of powder or liquid supplied is adjusted to a predetermined mixing concentration. Adjustment is made using the device 23 and the flow rate adjustment device 20. Note that the adjustment of liquid and powder is not automatic control, but is performed using powder supply device M2.
3. The flow rate adjustment device 20 can also be adjusted manually and simply.

When using the apparatus of the present invention to sprinkle powder on the surface of granules, for example, the amount of nylon pellets that are granules supplied is
2 K g/h, and the sleeve supply amount to the granules is 39
0PP seal, 16.2 g/h, supply amount of calcium stearate to granules: 850 ppm, 35.9 g/h
h, and the superficial velocity in the large-diameter cylindrical parts 1 to 4, that is, the flow rate of nitrogen gas, is 0.7 m/sec, and if 250 cc is sampled every 3 minutes after 30 minutes of operation, the powder adhesion concentration will be 800 ~ It was 910 ppm.

As shown in FIG. 1, one embodiment of the present invention has been described in the case of so-called co-current flow in which both gas and particles move from the bottom to the top, but as shown in FIG.
The gas is the same as in Fig. 1 in that it is moved sequentially from the bottom to the top, but unlike in Fig. 1, the granules are not introduced from the bottom, but are fed into the granule supply hopper provided at the top. It is also possible to use a so-called same-wave method in which the gas is introduced into a tank 50 and sequentially moved to the lower stage while being fluidized by the gas rising from below.

In this case, unlike the order shown in FIG. 1, liquid is first injected into the uppermost cylindrical portion 1, and then powder is supplied into the next cylindrical portion 2.

In this way, the granules introduced from above are fluidized and the liquid is evenly applied to the surface, and then the powder is evenly applied to the outer shell.

In this way, the cylindrical body 3.4 in the next stage is gradually fluidized and descends, and is discharged to the outside of the system via the rotary feeder (aerodynamic feeder) 12 installed below the side of the cylindrical part 4 in the final stage. Ru. In this method, the granule supply device ll
In order to prevent the granules introduced from below from escaping into the gas discharge pipe 31 due to the gas flow rising from below, a filter with a mesh finer than the size of the granules is used. 50a is provided above the granule supply hopper.

As described above, in the case of FIG. 2, which is another embodiment of the present invention, the position and flow of granule input, the order of supply of liquid and powder, and the finish of coated granules (products) It goes without saying that the embodiment is almost the same as the embodiment shown in FIG. 1, except for the discharge method that is different from that shown in FIG.

[Effect of the invention] In the present invention, as described in the claims,
Using a device in which multiple small-diameter cylindrical parts and large-diameter cylindrical parts are successively stacked, the granules are fluidized and circulated, and a liquid such as oil is first poured into the granules. Since the particles are introduced and sprinkled, and then the powder is introduced, the powder can be uniformly and reliably sprinkled on the surface of the granules. Of course, continuous powdering can be achieved using relatively small and simple equipment. Furthermore, it is possible to continuously sprinkle powder while fluidizing the granules, so powder can be sprinkled while the granules are being transported by gas.
Very efficient.

[Brief explanation of the drawing]

FIG. 1 is a system diagram (part 1 longitudinal sectional view) showing one embodiment of an apparatus for carrying out the method of the present invention, and FIG. 2 is a system diagram (part 1 longitudinal sectional view) showing another embodiment of the invention. (longitudinal cross-sectional view). 1 to 5...Large diameter cylindrical part, ■a to 5a, lc to 4C...Truncated conical cylindrical part, lb to
5b...Cylindrical part, 6-10...Small diameter cylindrical part, 1
1... Granule supply device, 13... Blower, 18...
Gas and particle inlet, 19...Liquid supply device, 22...Nozzle, 23.
・・Powder supply device, 25・・Compressor, 28・
... Powder supply port, 29 ... Granule discharge port, 32.
...Bag filter, 36...Differential pressure detector, 50...
- Granule supply hopper, 106-110... small diameter cylindrical part. Patent applicant: Ube Industries, Ltd. Figure 1

Claims (14)

[Claims] (1) Using a device in which multiple large-diameter cylindrical parts and small-diameter cylindrical parts are stacked vertically and alternately, the particles introduced into the cylindrical cylinder are introduced from the bottom of the cylindrical part. While being fluidized by the action of A method of coating the surface of granules. (2) A method of coating the surface of granules with the coating material according to claim 1, using only powder, only liquid, or both liquid and powder as the coating material. (3) Nitrogen gas or air is used as the gas introduced from the lower side of the cylindrical part, and oil and powder are used as the coating material sprinkled into the granules.The coating material according to claim 1 is applied to the granules. How to coat the surface. (4) A liquid is sprinkled into the fluidized granules in the cylindrical part, and then powder is sprinkled into the granules sprinkled with the liquid, or A method of coating the surface of granules with the coating material according to item 3. (5) A device is provided in which a plurality of large-diameter cylindrical parts and small-diameter cylindrical parts are vertically stacked alternately, a gas inlet is provided at the lower end of the lowest cylindrical part, and a gas inlet is provided at the lower end of the lowest cylindrical part, and the uppermost cylindrical part A gas outlet is provided in the shaped cotton, a granule inlet is provided in either the bottom or top cylindrical part, and a granule outlet whose surface is coated with a coating material is provided in the other cylindrical part. A device that coats the surface of particles with a coating material, which has a coating material introduction part on the cylindrical part on the body introduction side. (6) An apparatus for coating a particle surface with the coating material according to claim 5, using at least one of a liquid introduction section and a powder introduction section as the coating material introduction section. (7) A liquid introduction part is provided in the cylindrical part on the granule introduction side, and a powder introduction part is used on the downstream side of the granules.
An apparatus for coating the surface of granules with the coating material described in 1. (8) An apparatus for coating the surface of granules with the coating material according to claim 5, in which large-diameter cylindrical portions and small-diameter cylindrical portions are sequentially and alternately stacked on the same axis. (9) An apparatus for coating the surface of granules with the coating material according to claim 5, wherein the liquid introduction part and the powder introduction part provided in the cylindrical part are provided on the axis of the large diameter cylindrical part. (10) Provide the liquid introduction part in the lowermost large diameter cylindrical part,
An apparatus for coating the surface of granules with the coating material according to claim 5, wherein the powder introduction portion is provided in a large-diameter cylindrical portion above the powder introduction portion. (11) An apparatus for coating the surface of granules with the coating material according to claim 5, wherein the liquid introduction part and the powder introduction part are provided in the lowermost large-diameter cylindrical part. (12) Shape in which a large-diameter cylindrical portion is stacked in order from bottom to top, including a truncated conical cylindrical portion facing downward, a cylindrical portion, and a truncated conical cylindrical portion facing upward. An apparatus for coating the surface of granules with the coating material according to claim 5. (13) A patent in which the angle of inclination of the truncated conical cylindrical part facing the lower side of the large-diameter cylindrical part is 1 to 10 degrees larger than the angle of repose of the particle group to be placed in the cylindrical part. An apparatus for coating the surface of granules with the coating material according to claim 5. (14) Measure the differential pressure between the two cylindrical bodies, and depending on the magnitude of this differential pressure with respect to the set differential pressure, the flow rate of the gas introduced from below the bottom cylindrical part, the pressure of the gas, and the particles to be introduced An apparatus for coating the surface of granules with the coating material according to claim 5, which is provided with a device capable of adjusting the amount of particles and the amount of powder to be added.