JPH0355532Y2 - - Google Patents

Description

[Detailed description of the invention] <Field of industrial application> This invention is a continuous quantitative supply of powder in which the powder in a hopper is conveyed and discharged by the rotation of a ribbon-shaped screw in a horizontal discharge pipe that communicates with the hopper. Regarding equipment.

<Prior art and its problems> FIG. 3 is a schematic diagram illustrating a powder continuous quantitative supply device 1. That is, it consists of a hopper 11, a horizontal discharge pipe 2 communicating with the lower part of the hopper 11, and a vertical discharge pipe 3 connected to the horizontal discharge pipe 2. Inside the horizontal discharge pipe 2, a long flat material is arranged in a spiral shape, that is, a ribbon. A ribbon-shaped screw 4 is arranged, and the ribbon-shaped screw 4 is rotated in a predetermined direction via a sprocket 51 and a screw shaft 52 by a driving force from a motor (not shown). Further, the screw shaft gear 5 is attached to the screw shaft 52.
3 is installed, and this screw shaft gear 5
Hopper 1 via arm shaft gear 54 meshed with hopper 3
The agitator 12 is rotated by the arm shaft 12a in the powder powder 1 to stir the powder, and the powder is loosened and sent to the screw section. Usually, the ribbon-shaped screw 4 is rotated at 15 to 75 rpm to transport the powder in a predetermined direction within the horizontal discharge pipe 2. The ribbon-shaped screw 4 is a screw having a predetermined spiral pitch, and one pitch of powder maintains a constant bulk density, that is, is continuously conveyed and discharged in a constant quantity in the direction of the rotation axis of the screw. Adjustments to increase or decrease emissions are
This is done by changing the rotational speed of the ribbon-shaped screw 4.

FIG. 4 is an enlarged view of the X part in FIG.
This figure shows the position of the ribbon-shaped screw 4 at the intersection 2-3 of the horizontal discharge pipe 2 and the vertical discharge pipe 3. The ribbon-shaped screw 4 has its tip 41
An inclined surface 43 is provided between the top portion 42 and the top portion 42, that is, approximately 1/2 pitch. The powder 6 thus conveyed pitch by pitch is finally conveyed from the inclined surface 43 into the vertical discharge pipe 3 and discharged. However, when the rotational speed of the ribbon-shaped screw 4 is low, or when the powder 6 itself has a high cohesive property, for example, when the moisture content is high,
As shown in the figure, the powder 6a adheres to the inclined surface 43 and accumulates.
remain as. When the ribbon-shaped screw 4 further rotates, the deposited powder 6a is deposited as shown in FIG.
becomes a so-called block and slides down from the inclined surface 43.

As described above, if the powder 6 becomes the accumulated powder 6a and falls in lumps every time the ribbon-shaped screw 4 rotates,
The powder 6 is discharged intermittently, and the variation in the amount of continuous supply during continuous constant supply becomes significantly large.

In particular, it is a so-called loss-in-weight type powder quantitative feeding device that reads the amount of powder reduced in the hopper per unit time and sequentially carries out the powder while maintaining a constant supply amount to the next process. In this case, each time the accumulated powder is discharged, the shock sensed by the load cell is large, and the controller and inverter must rapidly increase or decrease the motor rotation. This will also impair its own durability. For this reason, even in devices where the screw normally rotates between 15 and 75 rpm, there is a problem in that it can only be used in a relatively high speed rotation range (30 rpm) in order to maintain continuous quantitative supply accuracy.

In order to solve these conventional problems, as shown in FIG. 6A and its side view B, a grid 7 is provided at the intersection 2-3, and the accumulated powder 6a is I also thought about breaking it down. However, if the cross bars of the grid 7 and the grid mesh 73 formed by the grid bars 71 and 72 are large, the accumulated powder 6a cannot be broken up in the low speed region, and the same intermittent discharge phenomenon occurs as described above. Also, if the grid 73 is fine, the grid 7
This causes clogging and prevents the supply of powder 6. Furthermore, as shown in FIG. 7, a method has been proposed in which a stirring bar 8 is attached to the substantially central rotation center side of the inclined surface 43 of the ribbon-shaped screw 4, but this stirring bar 8 has a shaft 81 directly connected to the ribbon-shaped screw 4. Since the stirring blade 82 is installed vertically on the shaft 81, the stirring blade 82 rotates at the same speed as the ribbon-shaped screw 4. Therefore, if the ribbon-shaped screw 4 rotates at a low speed, the stirring blade 82 also rotates at a low speed, and the accumulated powder 6a cannot be scraped out, resulting in the same intermittent discharge phenomenon as described above.

None of the above-mentioned improvement plans can prevent the phenomenon of intermittent discharge of powder in the low speed range.
Therefore, the device can only be used in high speed ranges. Therefore, in order to widen the range of supply to the next process, it is necessary to separately provide a device having a small-capacity feeder and a device having a large-capacity feeder.

<Means for solving the problem> The present invention was devised in view of the above problem.
The tip of the ribbon-shaped screw is retreated from the intersection formed by the horizontal discharge pipe and the vertical discharge pipe to form a scraping area, and within this scraping area, a scraping mechanism that is driven by a separate drive source from the ribbon-shaped screw and rotates at high speed is installed. It was established.

<Function> In other words, even if the powder that is quantitatively conveyed by the ribbon-shaped screw in the horizontal discharge pipe causes accumulated powder on the sloped surface of the screw tip, the powder is transported by the ribbon-shaped screw in the scraping area before reaching the vertical discharge pipe. It is crushed and dispersed by a scraping mechanism that rotates at a higher speed. Therefore, it is possible to continuously supply a fixed amount of powder even when the ribbon-shaped screw rotates at a low speed. This makes it extremely suitable for a loss-in-weight type powder quantitative supply device.

<Example> The powder continuous quantitative supply device of the present invention will be described below based on the drawings.

Furthermore, the hopper 11, the horizontal discharge pipe 2, the vertical discharge pipe 3, and the ribbon-shaped screw 4 which constitute the quantitative feeding device
etc., have the same configuration and function as the conventional example, and therefore will be described using the same numbers as above.

FIG. 1 is a schematic diagram illustrating a scraping region Z formed at the intersection 2-3 of the horizontal discharge pipe 2 and the vertical discharge pipe 3, and a scraping mechanism 9 provided within the region.

The scraping area Z is formed by retracting the tip 41 of the ribbon-shaped screw 4 inward to the horizontal discharge pipe 2, and the height h is approximately equal to the diameter of the horizontal discharge pipe 2, and the length l is the width of the ribbon-shaped screw 4. The radius of rotation is approximately 1/4 to 1/2 of the rotation radius of 4.

The scraping mechanism 9 is provided with a scraping section disposed within the scraping area Z. The scraping mechanism 9 includes a rotating shaft 91 rotated by an electric motor M separate from the motor of the ribbon-shaped screw 4, and a scraping part 92 attached to the tip of the rotating shaft 91. 4, and the direction of rotation of the rotating shaft 91 is preferably the same as that of the ribbon-shaped screw 4. Moreover, the rotational speed is much higher than that of the ribbon-shaped screw 4, for example, 100 to 200 rpm. The scraping portion 92 is formed by a bifurcated central crushing blade 92a provided at the tip of the rotating shaft 91 and peripheral dispersing blades 92a formed by a plurality of narrow blade plates radially attached to the rotating shaft 91. configured. Among these, the peripheral dispersion blade 92b has a structure that rotates at least within the scraping region Z.

Next, the function of the scraping mechanism 9 having the above configuration will be explained. As mentioned above, the powder 6 deposited on the inclined surface 43
a is formed, and even if it slides down from the inclined surface 43 with the rotation of the ribbon-shaped screw 4, it is not directly discharged to the vertical discharge pipe 3, but is crushed by the central crushing blade 92a in the scraping area Z, and the surrounding It is further finely dispersed by the dispersion vane 92b and discharged from the vertical discharge pipe 3.

Even if the accumulated powder 6a is generated in this manner, it is crushed and dispersed by the scraping mechanism 9 in the scraping area Z, so that stable continuous quantitative supply of the powder is possible.

FIG. 2 shows another embodiment of the scraping mechanism 9, in which the central crushing blade 92a is formed into a substantially triangular pyramid shape by, for example, four triangular plates. Since the central crushing blade 92a has a pointed tip, no reaction force acts on the powder conveyed from between the pitches of the ribbon-shaped screw 4, in other words, it does not affect the bulk density.

Therefore, according to this device, the ribbon-shaped screw 4
The rotation does not cause intermittent discharge even at a low speed of about 5 rpm, for example. Therefore, a possible supply range of about 1:10 to 1:15 can be obtained with one feeder.

<Effects of the invention> As described above, the powder continuous quantitative supply device of the present invention has the following advantages:
Even if accumulated powder is generated at the tip of the ribbon-shaped screw, it can be crushed and dispersed, so there is no intermittent discharge/fall phenomenon, and it is possible to continuously supply a fixed amount of powder with high accuracy. Moreover, the possible supply range with a single feeder has been significantly expanded compared to conventional methods, and even in the case of a so-called lost-weight method powder quantitative supply device, the device itself can be easily supplied without reducing its quantitative supply accuracy. It has extremely practical effects, such as not impairing the durability of the product.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram illustrating a scraping mechanism according to the present invention, FIG. 2 is a diagram showing another embodiment of the scraping mechanism, FIG. 3 is a schematic diagram of a powder continuous quantitative supply device, The figure is an enlarged view of the X section in Figure 1, Figure 5 is a diagram explaining the sliding of the accumulated powder formed at the tip of the ribbon-shaped screw, and Figure 6A is an explanation of the grid provided at the intersection. FIG. 7B is a side view thereof, and FIG. 7 is an explanatory diagram of a stirring bar provided on the ribbon-shaped screw. 1... Powder continuous quantitative supply device, 11... hopper, 12... agitator, 2... horizontal discharge pipe, 3...
...Vertical discharge pipe, 4...Ribbon-shaped screw, 41
... Tip, 43 ... Inclined surface, 6 ... Powder, 6a ...
... Accumulated powder, 9... Scraping mechanism, 91... Rotating shaft, 92... Scraping part, 92a... Center crushing blade, 92b... Peripheral dispersion blade, Z... Scraping area.

Claims (1)

[Claim for Utility Model Registration] Powder in a hopper is conveyed by the rotation of a ribbon-shaped screw in a horizontal discharge pipe connected to the hopper, and the powder is continuously discharged from a vertical discharge pipe connected to the horizontal discharge pipe. In the quantitative feeding device, the tip of the ribbon-shaped screw is retreated from the intersection of the horizontal discharge pipe and the vertical discharge pipe to form a scraping region, and a drive source separate from the ribbon-shaped screw is provided in the scraping region, and A powder continuous quantitative supply device characterized by being equipped with a scraping mechanism that rotates at high speed.