JPH09294925A - Powder mixing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a powder mixing apparatus which can homogenize even a mixture in which a large amount of powder is added with only a small amount of another kind of powder. SOLUTION: The upper part of the second hopper-shaped tank 32 is made to communicate with the bottom part of the first tank 31 through piping 34 with a butterfly type intermediate valve 33. The bottom part of the second tank 32 is made to communicate with the upper part of the first tank 31 by piping 36 with a rotary valve 35 and piping 38 for pneumatic transportation with a valve 37. Powder is mixed by being circulated between the tanks 31, 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder mixing apparatus, and more particularly, to a powder mixing method in which a powder of a different type from the first powder can be mixed very uniformly when added in a small amount. Regarding the device. More specifically, the present invention relates to a powder mixing device of the type that uses gravity flow.

[0002]

2. Description of the Related Art As a gravity mixing type mixer utilizing a power flow, an introduction pipe shown in FIG.
There are a resin-like inner cylindrical shape shown in (b) and an intermittent inner cylindrical shape shown in FIG. 3 (c). The principle of this gravity-mixing type mixer is that a quantity of powder that gravity-flows in the storage tank is taken out from each part of the storage tank in a fixed amount and collected to form a uniform mixture. This gravity mixing type mixer is used when a large amount of powders having little difference in powder properties are mixed, but segregation may occur in powders having a wide particle size distribution.

In FIG. 3A, a large number of introducing pipes 2 are arranged in the mixing tank 1, and the upper end of each introducing pipe 2 is a nozzle (opening) 3. A merging chamber 5 is provided below the central flow port 4 of the mixing tank 1, and an introducing pipe 6 is also disposed therein. The powders from the respective introduction pipes 2 and 6 and the central flow-down port 4 are mixed in the merging chamber 5 and taken out from the outlet 7.

In FIG. 3 (b), an inner cylinder (vertical inner cylinder) 11 is erected at the center of the mixing tank 10, and a large number of dendritic inner cylinders 12 are obliquely branched therefrom. Each dendritic inner cylinder 12
Of the inner cylinder 12 is open, and the powders taken in the inner cylinders 12 are mixed in the inner cylinder 11 and taken out from the outlet 13.

In FIG. 3C, the pipe 1 is placed in the storage tank 15.
The powder introduced from 6 is the perforated plate 17 or the inner cylinder 18
Gradually falls through and is mixed. The mixed powder is taken out through the rotary valve 19 and the pipe 20. It should be noted that the powder can be circulated to the upper portion of the tank body 15 via a pipe 22 branched from a switching valve 21 of the pipe 20. A powder separator (separator) 23 is provided above the storage tank 15.
Is installed so that the dust-free air can be discharged into the atmosphere.

[0006]

As a result of various researches, in the above-mentioned conventional gravity type mixer, as in the case where an additive is mixed with cement, for example, the first powder (for example, cement) is added. A second powder of a different type (eg,
When only a small amount of (additive) was added and mixed, it was found that the uniformity after mixing was insufficient.

The present invention solves the above-mentioned problems of the prior art and provides a powder mixing apparatus capable of extremely uniformly mixing a large amount of powder even when a small amount of another kind of powder is added and mixed. The purpose is to provide.

[0008]

In the powder mixing apparatus of the present invention, the first tank into which the powder to be treated is introduced and the powder from the first tank are introduced via the first transportation means. And a second transportation means for returning the powder from the second tank to the first tank, at least one of the first and second transportation means being air. It consists of a transportation device.

In such a powder mixing apparatus, a plurality of powders are supplied to the first tank in a required amount each (these powders may be mixed to some extent in advance, or they may not be mixed at all). Then, the powder in the first tank is transferred to the second tank and then returned from the second tank to the first tank again. This is set as one cycle, and a plurality of cycles are repeated. At least one of the transfers between the tanks is pneumatic, so that the powder is well mixed while pneumatically transported.

Further, the powder particles transported from one tank to the other tank are mixed when they are charged into the other tank, and the mixing of the powder particles in the tank as a whole is made uniform. Once it becomes expensive.

According to the present invention, the second tank is arranged below the first tank, and the bottom portion of the first tank and the top portion of the second tank are gravitationally dropped through the valve. It is preferable that they are connected so that they can be supplied.

With this structure, the powder in the first tank falls into the second tank by its own weight by opening the valve, and the power cost for transferring the powder is significantly increased. Will be reduced.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of a powder mixing apparatus according to an embodiment, in which raw material powder (about 65% by weight of cement and about 34 gypsum in this embodiment) is fed from a crusher. A powder in which 1% by weight of the additive and about 1% by weight of the additive are mixed in advance in the pulverizer) is supplied to the hopper-shaped first tank 31. An upper portion of a hopper-shaped second tank 32 is connected to a bottom portion of the first tank 31 via a pipe 34 with a butterfly type intermediate valve 33. The bottom of the second tank 32 and the top of the first tank 31 are connected by a pipe 36 with a rotary valve 35 and a pipe 38 for pneumatic transportation with a valve 37. Air is supplied to the pipe 38 from a blower 39 so that the powder can be transported by air. A product take-out pipe 40 is branched from the pipe 38, and a valve (not shown) is also provided in this pipe.

A bag filter 41 is provided above the first tank 31 to remove air from the first tank 31 and release it into the atmosphere. The air in the second tank 32 is also introduced into the bag filter 41 through the pipe 42 to remove dust and then released into the atmosphere.

The first and second tanks 31 and 32 are provided with vibrators 43 and 44 and a powder weight detecting load cell 47, respectively. Reference numeral 45 indicates a sampling hole installation location.

Next, the powder mixing operation by this powder mixing apparatus will be described with reference to FIG. The following operation control is performed by a computer.

First, a predetermined amount of powder is introduced into the first tank (upper tank) 31, and the bag filter 41 is operated. Next, after setting the initial value of the number of times of mixing to 0,
The intermediate valve 33 is opened, and the vibrator 43 of the tank 31 is opened.
Is operated to drop almost all of the powder in the tank 1 into the second tank (lower tank) 32.

Next, after closing the intermediate valve 33 and stopping the vibrator 43, the blower 39 and the rotary valve 35 are started to operate. As a result, the powder in the tank 32 begins to return to the tank 31 via the pipe 38.

When the amount of powder in the tank 31 has increased to the specified amount, the intermittent operation of the vibrator 44 of the tank 32 is started. The intermittent operation of the vibrator 44 is started even when the amount of powder in the tank 32 does not decrease to the specified amount even after 2 hours have passed since the rotary valve 35 was started.

After that, when the amount of powder in the tank 31 has increased to a preset amount, the timer is started and the rotation of the rotary valve 35 is continued for 30 minutes thereafter.

After 30 minutes, the rotary valve 35 and the vibrator 44 are stopped, and after waiting for 2 minutes, the blower 3
9 is stopped. Then, the mixing number N is increased by one.

After repeating this series of mixing cycles a total of three times, the bag filter 41 is stopped to terminate the mixing, and the mixed powder is pneumatically transported to the product tank as needed.

According to such a powder mixing apparatus, it was found that even a very small amount of the fast-hardening cement admixture can be mixed extremely well with cement and gypsum. This is when the powder falls from the first tank 31 to the second tank 32, or from the second tank to the first tank 3.
When it is returned to 1, the total amount of powder is in the tank 32 or 31.
It is considered that this is because it is sufficiently mixed within the pipe 38 that returns from the tank 32 to the tank 31 while being mixed inside.

The raw material powders were mixed using various mixers shown in FIG. 3, but they could not be mixed to the degree of uniformity as high as the powder mixing apparatus of the present invention. .

[0025]

As described above, according to the powder mixing apparatus of the present invention, powder can be mixed to a high degree of uniformity.

[Brief description of drawings]

FIG. 1 is a system diagram of a powder mixing device according to an embodiment.

FIG. 2 is a flowchart showing the operation of the powder mixing apparatus according to the embodiment.

FIG. 3 is a cross-sectional view showing a conventional example.

[Explanation of symbols]

 31 First Tank 32 Second Tank 35 Rotary Valve 39 Blower 41 Bag Filter 43,44 Vibrator 47 Load Cell

Front Page Continuation (72) Inventor Atsushi Hasegawa 1 Konan-cho, Hachimansai-ku, Kitakyushu, Fukuoka 1 Mitsubishi Materials Corporation Cement Development Center

Claims (2)

[Claims] 1. A first tank into which a powder to be treated is introduced, a second tank into which powder is introduced from the first tank via a first transportation means, and a second tank And a second transporting means for returning the powder from the first transporting means to the first tank, wherein at least one of the first and second transporting means is an air transporting device. 2. The first tank according to claim 1, wherein the second tank is arranged below the first tank, and the bottom of the first tank and the top of the second tank are powdered via a valve. The powder mixing device is characterized in that it is connected so that it can be supplied by gravity falling.