JPH0542293B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a novel method and apparatus for mixing powder and granular materials that can mix powder and granular materials without using a stirrer.

[Conventional technology]

Powder and granule materials for plastic molding are required to have a constant particle size, degree of polymerization, and moisture content in order to obtain good molded products. The materials generally vary in powder size, etc., and depending on the material, multiple types of resin pellets may be used.

By the way, in the past, when powder and granule materials were dried immediately after production and mixed in order to make the powder and granule materials homogeneous, each resin pellet was stored in a drying hopper and hot air was applied for a predetermined period of time. The method used is to dry the powder and then stir the dried powder or granular material.

However, when performing dry mixing using this method, a large mixer equipped with an agitator is required, making the equipment itself large-scale and requiring time and effort to clean when changing materials. It has become a thing.

[Problem to be solved by the invention]

The present invention is proposed to solve the above problems, and includes a mixing method that eliminates the need for larger equipment and ancillary equipment due to the use of an agitator, and facilitates cleaning work when changing materials. It is an object of the present invention to provide an apparatus that can effectively carry out a mixing method.

[Means to solve the problem]

The present invention proposed to achieve the above object,
A method of mixing powder and granule material stored in a dry hopper exhibiting mass flow characteristics while supplying another type of powder and granule material through a suction hopper exhibiting funnel flow characteristics disposed above the dry hopper. By alternately repeating the forced return of the granular material stored in the drying hopper into the suction hopper and the suction replenishment of a different type of granular material into the suction hopper, these granular materials are dried. The material is stored in the suction hopper until it reaches a predetermined amount and forms a plurality of material layers, and then the granular material retained in the suction hopper is transferred to the granular material that is later introduced into the suction hopper. After performing the combining step of dropping and discharging the materials into the drying hopper at once so that they are discharged first, the combined materials stored in the drying hopper are returned to the suction hopper to remove the suction. The powder and granule material in the hopper is further stored up to a predetermined amount, and then the powder and granule material stored in the suction hopper is discharged first so that the powder and granule material that was later put into the suction hopper is discharged first. The method is characterized in that a plurality of materials are mixed by sequentially repeating the process of dropping and discharging them into the drying hopper all at once so that the materials are mixed.

In addition, the apparatus of the present invention proposed at the same time for carrying out the method of the present invention has a drying hopper having a material delivery means such as a rotary valve and exhibiting a mass flow characteristic in discharging the powdery material, and an upper part of the drying hopper. It has a level switch that detects the accumulation level of powder and granular material, and a suction hopper that generates a shot path due to the funnel flow characteristic when discharging the powder and granular material, and an on/off signal of the level switch. a control valve for controlling the dropping of a predetermined amount of granular material into the drying hopper; a material replenishing means for forcibly sucking the granular material into the suction hopper; and a granular material stored in the drying hopper. A material return means for forcibly returning the material into the suction hopper by pneumatic transport, and a sequence controller that sequentially controls the material delivery means, the control valve, the material supply means, and the material return means according to a predetermined program. It consists of

Furthermore, the term "funnel flow" used in the present invention refers to a funnel-shaped flow that is formed when the powder or granule material stored in the hopper is discharged, with the powder or granule material introduced last being placed first. ``Mass flow'' refers to the phenomenon in which powder and granule materials that have been input into the hopper reach the discharge port directly and are discharged, and "mass flow" refers to the phenomenon in which the powder and granule materials stored in the hopper are sequentially discharged from the lower layer and are discharged. At the same time, this refers to a phenomenon in which the entire granular material stored in the hopper moves downward.

In the present invention, the drying hopper exhibits mass flow characteristics, and the suction hopper exhibits funnel flow characteristics. When the outlet is opened, a funnel-like flow is formed, and the powder or granule material that is later charged into the hopper reaches the outlet and is discharged in priority to the powder or granule material that has been introduced earlier. In this specification, this phenomenon is described as a short pass.

〔Example〕

The invention will now be described with reference to the accompanying drawings.

FIG. 1 is a system configuration diagram showing an outline of the apparatus of the present invention, and FIG. 2 is a block diagram showing the configuration of control elements of the system.

In the figure, 1 is a suction hopper for storing powder and granular material, and has a storage tank of a predetermined amount, a level switch 14 is provided inside the hopper, and an automatic opening/closing control valve, that is, a suction hopper valve, is provided at the bottom of the hopper 1. There are 10.

When the sucked granular material reaches a predetermined amount, the level switch 14 outputs an OFF signal (material supply stop signal), and specifies to stop supplying the granular material. The valve 10 is controlled by the sequence controller 4 and is opened when the granular material stored in the hopper 1 is fed into the drying hopper 2. When the control valve 10 is opened, the suction hopper 1 is opened. The granular material stored in the drying hopper 2 forms a shot path due to the funnel flow and falls into the drying hopper 2 all at once.

A tube 22 with a suction nozzle 17 at its tip extends from the suction hopper 1, and the containers 19a to
The granular materials A to C accommodated in the 19c are sucked into the suction hopper 1 through the suction nozzle 17 as will be described later.

Note that 1a is a screen filter that prevents the sucked powder material from entering into the pipe 21.

Further, a pipe 21 extending from the suction hopper 1 passes through a bag filter 6 for dust collection to an aftercooler (for resin cooling and blower protection) 8, and is further connected to a roots blower 5 serving as an air supply source.

An exhaust valve 13 is located downstream of the roots blower 5.
is provided, and by controlling the opening and closing of this valve 13 by the sequence controller 4, suction replenishment and forced return of the powder material as described later are performed.

The exhaust valve 13 is configured so that the suction hopper 1 is connected to the container 19.
It is opened when sucking the granular material in a to 19c, and at this time, the roots blower 5 reduces the pressure in the suction hopper 1 through the pipe 21.

On the other hand, the pipe 20 extending from the roots blower 5 is
It is connected to the suction hopper 1 through a pipe 23, and the pipe 21, back filter 6, aftercooler 8, and Roots blower 5 constitute a closed loop for air circulation. Here, when the exhaust valve 13 is closed, the Roots blower 5 is started, and the rotary valve 11 is started, the powder material stored in the drying hopper 2 is sucked into the hopper 1 by compressed air supplied through the pipe 20. Each device that constitutes the closed loop of the above-mentioned air transport constitutes a material return means for the granular material.

2 is a drying hopper for drying the powder material fed from the suction hopper 1, and has a storage tank with a sufficiently larger capacity than the suction hopper 1, and when the rotary valve 11 described later is activated, A defeaser cone 2a is provided at the bottom in order to make the discharge of the powder material more similar to mass flow characteristics without producing a shot pass. Also, inside the drying hopper 2, a pipe 18 for feeding dry hot air supplied from the steam heater 3 is provided.
A rotary valve 11 is provided at the bottom of the drying hopper 2 so that the dried granular material can be delivered into the pipe 20.
Although the rotary valve 11 constitutes a material discharging means, the material discharging means is not limited to the rotary valve, but may be any other means for discharging the material by volumetric measurement.

In addition, 27 is an opening/closing damper for discharging the powder and granular material dried in the drying hopper 2, and the powder and granular material dried and mixed in the drying hopper 2 finally opens the opening/closing damper 27. and stored in the container 16 or the like.

Hot air sent out from the steam heater 3 for drying the granular material stored in the drying hopper 2 is sent to the cyclone 9 via the exhaust pipe 24 to collect dust, and then passed through the pipe 25. The air fed into the dehumidifying unit 7, where it is regenerated and dried again, is fed into the steam heater 3 via the pipe 26. The steam heater 3 is provided with a steam heater valve 12 for controlling the temperature of dry air, and the temperature of the dry air is controlled by opening and closing the heater valve 12 to control the amount of steam sent from the steam source. In this embodiment, a steam heater is used to heat the air, but it goes without saying that other heaters may be used to heat the air.

Further, 15 is a shifter for distributing multiple types of powder and granular materials A to C into the respective containers 19a to 19c, and although it is drawn above powder and granular material A in FIG. 1, it can be moved as necessary. Each container 19 contains a different type of powder or granular material.
b, 19c.

Next, the method of the present invention will be explained using the apparatus shown in FIG. 1 as an example.

When the discharge valve 13 is opened and the Roots blower 5 is activated in response to a command from the sequence controller 4, the pressure inside the suction hopper 1 is reduced through the pipe 21, and the powder particles in the container 19a are discharged through the suction nozzle 17. Body material A is sucked into the suction hopper 1 through the tube 22 (at this time, the valve 10 is closed).

As a result, the sucked granular material A only passes through the screen filter 1a, with air acting as a transport medium.
The air is sucked into the pipe 21 through the exhaust valve 13 and released into the atmosphere. Thus, suction hopper 1
The powder material A is sucked into the chamber, and when a predetermined amount is reached, the level switch 14 is turned off.

Then, the sequence controller 4 detects this signal and opens the suction hopper valve 10. When the suction hopper valve 10 is opened, the powder material A in the suction hopper 1 falls into the drying hopper 2 while creating a shot path. The above operation is performed by sending a suction stop signal to the sequence controller 4 (this signal is sent to the suction nozzle 17, for example).
While checking the supply status of materials, the operation is performed until the input is made by operating the operation panel (not shown) (outputting) (the above is the material A receiving process, see FIG. 3).

When the supply of material A is completed, the controller 4 closes the valve 10 and opens the steam valve 12. Then, dry air is sent into the drying hopper 2 through the pipe 18, and the stored powder material A is dried by this dry air, and the moist air after drying passes through the pipe 24 and is sent to the exhaust cyclone 9. After the dust is collected, it is sent to the dehumidification unit 7 through the pipe 25. In the dehumidifying unit 7, this humid air is heated and cooled to remove moisture, and the regenerated and dried air is sent through the pipe 26 again into the steam heater 3, where it is heated, and then sent to the drying hopper 2. , the powder material A is dried.

In this way, the drying hopper 2
After the powder material A is dried by passing hot air inside, the steam valve 12 is closed again.
A material drying process, see Figure 3).

After the drying process is completed, a dehumidifying process and a mixing process are performed.

In this mixing process, the material return means is driven,
The powder material A stored in the drying hopper 2 is forcibly returned to the suction hopper 1. That is, the roots blower 5 is driven again, the exhaust valve 13 is closed, and the rotary valve 11 is driven (at this time, the suction hopper valve 10 is in a closed state).

As a result, the air flow generated by starting the Roots blower 5 is as follows: Roots blower 5 → Pipe 20 →
The granular material is circulated through a closed loop formed by pipe 23 → suction hopper 1 → pipe 21 → bag filter 6 → aftercooler 8 → roots blower 5, and is discharged from drying hopper 2 by activation of rotary valve 11. A is sucked into the suction hopper 1 by this air flow and is forcibly returned into the suction hopper 1.

In this way, the powder material A in the drying hopper 2 is returned to the suction hopper 1, and when the stored amount reaches the level specified by the level switch 14, the sequence controller 4 detects this signal. to open the suction hopper valve 10.

As a result, the material A stored in the suction hopper 1 falls into the drying hopper 2 while creating a shot path, but at this time, the vertical positional relationship of the materials in the drying hopper 2 is disrupted. , uniformity is promoted.

The above mixing process is repeated for a preset time, and as a result, the drying hopper 2
The distribution state of the materials in a certain relationship is disturbed, and uniformity is promoted (above, material A mixing step, see FIG. 3).

After the above-mentioned mixing step is completed, a combining step, which is the main part of the present invention, is performed. During this matching process, material B is received at the same time, and the sequence controller 4 starts the roots blower 5, opens and closes the exhaust valve 13, and the rotary valve 1.
By selectively driving 1, suction replenishment of new powder material B and forced return of powder material A, which has already been stored in transport hopper 2, to suction hopper 1 are repeated alternately. be fed.

That is, the shifter 15 is moved to a container 19b containing another new material B, and the rotary valve 1 is
1, open the exhaust valve 13, supply a predetermined amount of material B into the suction hopper 1 through the suction nozzle 17, then close the exhaust valve 13, start the rotary valve 11, and supply the material B into the drying hopper 2. A predetermined amount of the stored powder material A is forcibly returned to the suction hopper 1.

At this time, it is important to keep the suction hopper valve 10 closed and the rotary valve 11
The amount of material stored in the hopper 2 that is returned and supplied at one time is set to be equal to or greater than the amount of suction replenishment by the suction hopper 1. For this reason, as the amount of material stored in the hopper 2 increases, the amount of one return by the rotary valve 11 also increases accordingly.

In this way, when the suction replenishment of new granular material B to the suction hopper 1 and the forced return of the granular material A stored in the drying hopper 2 are repeated alternately, the suction hopper 1 receives In this case, a multilayer material layer of new material B and already dried material A is formed, and when the accumulated amount of these materials reaches a predetermined level, the level switch 14 outputs an OFF signal,
The return of material A and the supply of material B will be stopped. When the sequence controller 4 detects this signal, the suction hopper valve 10, which had been closed,
is opened, and the materials A and B stored in the suction hopper 1 fall into the drying hopper 2 all at once while creating a shot path.

In the present invention, the materials A and B, which have been separated into multiple layers at this time, are mixed and housed in the drying hopper 2 (see the flowcharts in Figures 3 and 4 for the process of combining materials A and B). ).

The above-described combining process is performed until suction and replenishment of the new powder material B accommodated in the container 19b is completed, and when that process is completed, a drying process is performed as necessary. This drying process is carried out in the above-mentioned A
This is carried out in the same manner as the drying process for the materials, and then a similar mixing process is performed (the above is the drying and mixing process for materials A and B).

Finally, in this example, a C material receiving process is performed. During this process, A material-B material (mixture of A material and B material in the above step) and C
The process of combining materials A and B will be carried out in the same manner as described above.
material, C material joining process, see Figure 3).

Furthermore, after such a combining process is carried out, a drying process is also carried out in which dry air is passed through the granular materials A, B, and C stored in the drying hopper 2 for a predetermined period of time. , B material, C material drying process,
(See FIG. 3).Finally, the granular material that has undergone the drying process is mixed, and at this time, a cooling process is further performed as required. The cooling process in this case (above, A
After mixing, the dry powder material is discharged by opening the discharge damper, and the steam heater is activated to facilitate bagging. For example, when using a steam heater, cooling water such as water may be passed through a coiled pipe.

Steps 100→114 in FIG. 4 are a flowchart showing the operation of the alignment process which is the essential part of the present invention. Timers T1 and T2 are supply materials, respectively.
The supply time of return materials is specified, and the supply of these materials is controlled by the level switch in the small capacity hopper 1.
When it is turned off, it will run dry and then stop.

〔Effect of the invention〕

According to the present invention, when adding new powder or granule material to dry powder or granule material and mixing it, it can be carried out using a simple configuration that combines large and small hoppers and circular feed piping without using a mixer. Therefore, the device can be configured to be simple and compact.

In addition, changing materials and cleaning can be done easily, and maintenance is also easy.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the basic configuration of the device of the present invention;
The figure is a block diagram of the sequence controller and each control element, FIG. 3 is a time chart showing an example of the method of the present invention, and FIG. 4 is a flow chart showing the operation of the matching process. (Explanation of symbols), 1... Suction hopper, 2...
Drying hopper, 4...Sequence controller,
5... Roots blower, 10... Suction hopper (control valve), 11... Rotary valve (material delivery means), 13... Exhaust valve, 17... Suction nozzle, A, B, C... Powder material.

Claims (1)

[Scope of Claims] 1. Replenishing the powder or granule material stored in a dry hopper exhibiting mass flow characteristics with another type of powder or granule material through a suction hopper exhibiting funnel flow characteristics disposed above the dry hopper. This is a method of mixing the powder and granular material stored in the drying hopper, and alternately repeating forced return of the granular material stored in the dry hopper to the suction hopper and suction replenishment of another type of granular material into the suction hopper. By doing so, these powder and granule materials are stored in the suction hopper until a predetermined amount is reached and a plurality of material layers are formed, and then the powder and granule materials retained in the suction hopper are later transferred to the suction hopper. After performing a combining process in which the powdered material input into the drying hopper is dropped and discharged at once into the drying hopper so that it is discharged first, the combined material stored in the drying hopper is transferred into the suction hopper. By returning the granular material in the suction hopper, the granular material is further stored to a predetermined amount, and then the granular material stored in the suction hopper is used as powder that is later put into the suction hopper. A method for mixing powder and granular materials, characterized in that multiple types of materials are mixed by sequentially repeating the step of dropping and discharging the granular materials at once into the dry hopper so that the granular materials are discharged first. 2 It has a material delivery means such as a rotary valve,
It has a drying hopper in which the discharge of powdery material exhibits a mass flow characteristic, and a level switch placed above the drying hopper to detect the accumulation level of the powdery material, so that the discharge of powdery and granular material exhibits a funnel flow characteristic. a suction hopper that generates a short pass depending on its characteristics; a control valve that controls the dropping of a predetermined amount of the accumulated powder and granular material into the dry hopper according to on/off signals of the level switch; a material replenishment means for forcibly suctioning the dry hopper; a material return means for forcibly returning the granular material stored in the dry hopper to the suction hopper by pneumatic transport; the material delivery means, the control valve, the material replenishment means; What is claimed is: 1. A mixing device for powder and granular materials, comprising: a sequence controller that sequentially controls material return means according to a predetermined program.