JPS6245488B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for quantitatively discharging powder or granular material, a so-called metering device, and particularly to a metering device that separates and discharges a predetermined small amount from a storage tank or the like.

Although various devices are known for dispensing relatively large amounts of powder or granular materials such as wheat flour from storage tanks, very few dispensing devices that accurately separate small amounts have been proposed and have been desired for a long time. Conventionally, the current situation is that small quantities have relied on the manual labor of workers, and the amount of effort and time required to measure portions is by no means small, and the more accurate portions are desired, the more inefficient the portion portion work becomes. .
However, when attempting to use a dispensing device used for dispensing large quantities to disassemble small quantities, problems arose in terms of uniformity of discharge and dispensing accuracy. In other words, in a normal dispensing device, powder and granules are stored in a storage tank in advance, and during dispensing, the powder is fed by a feeder installed at the bottom of the storage tank, and the desired amount is separated and discharged from the discharge port. However, the density of the powder sent from the bottom of the storage tank to the feeder is not uniform due to the influence of the powder pressure stored in the storage tank. There was also a drawback that the discharge was uneven. It is known that a protrusion called a nose is provided on the inner wall of the storage tank to extend downwardly from the storage tank in order to eliminate the influence of the powder pressure inside the storage tank as much as possible and to facilitate the discharge of powder and granular material from the lower part of the storage tank. However, this nose alone does not completely solve the above-mentioned problem of uneven density of powder and granules during discharge.

If the density of the powder and granular material supplied by the feeder for discharge is uneven in this way, the amount of powder and granular material dispensed from the discharge port is not quantitative, and sometimes a large amount is discharged in a short period of time. In some cases, a small amount or almost no discharge occurs. If the discharge is not carried out quantitatively and continuously in this way, the accuracy in dispensing will be low in the small-volume dispensing and dispensing device that is the object of the present invention. This is because even though a predetermined amount is set to be discharged, the amount to be discharged at the final moment of the discharge process is not determined, and the final discharge amount affects the accuracy of the quantity. In order to improve the accuracy of the quantity, we have taken measures such as adopting a two-stage large and small screw feeder, and controlling the rotation speed of a single screw feeder to adopt a two-stage feeding system for large and small amounts. Various methods have been used, but the switching control required is complicated and requires a large amount of floor space.

Another factor that affects quantitative performance in small-volume fractionation and dispensing devices is the shape of the outlet. The outlet of conventional dispensing devices is a circular or rectangular opening formed in a discharge tube, around which a discharge guide tube is usually attached. The feeder usually has spiral blades and conveys the powder and granules through the discharge pipe while pushing them with the blades, but when the conveyed powder and granules reach the discharge port, most of the powder and granules between one pitch of the blades are removed. However, the next pitch of powder and granules falls and is discharged all at once before reaching the discharge port, so the discharge becomes discontinuous and does not lose quantitative properties. For this reason, the measurement accuracy will be reduced.

The present invention solves the above-mentioned problems that occur when a conventional large-volume dispensing device is applied to a small-volume dispensing device. By stirring and mixing with the air taken in from the outside, the powder and granules supplied by the feeder are given uniformity and fluidity, and the powder and granules discharged from the discharge port are given quantitative properties in order to improve the accuracy of dosing. It is something to do. Furthermore, separate from this, the discharge port is formed into a narrow slot shape, and the longitudinal direction of the slot is set so as to at least intersect with the blades of the feeder, thereby further increasing the quantitative discharge of the powder and granular material. The intersection angle between the feeder blade and the longitudinal direction of the slot is appropriately selected within a range of 90° or less, but the larger the intersection angle, the better the quantitative performance.

According to the present invention, it is possible to make the density of the powder and granular material sent from the storage tank to the feeder uniform, and to give quantitative properties to the discharge of the powder and granular material. By forming the elongated slot shape, it is possible to enhance the quantitative effect in conjunction with the above-mentioned quantitative property, and in particular, it is possible to improve the dosing accuracy in a small-dose dispensing device.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a powder/granular material dispensing device according to the present invention, and the dispensing device 1 is composed of a device main body 2 and a metering supply device 3 disposed on the top thereof.
Inside the quantitative supply device 3, there is a storage tank 31 as shown in FIGS. 2 and 3, with a stirring device 32 near its lower opening and a screw feeder 3 directly below it.
3 are arranged. A control panel 34 is provided on the front side of the metering supply device 3 for setting the amount of powder or granular material to be separated and controlling the amount operation. Inside the device main body 2 is a drive device 21 for driving the screw feeder 33 of the quantitative feeding device 3.
A weight detection device 22 using a load cell is provided on the front surface. A weighing container 23 for storing a predetermined amount of powder or granular material is placed on the weight detection device 22 .

As shown in FIG. 1, the storage tank 31 is charged with powder and granular material from its upper charging port 31a through a transport system 4 such as a pneumatic transport pipe or a belt conveyor.

The rear inner wall 31b of the storage tank 31 is provided with a nose 31c that slopes from the upper part to the lower part toward the center of the storage tank, and a space P is formed between the nose 31c and the rear inner wall 31b. For example, the nose 31c is approximately 65 mm relative to the rear inner wall 31b.
It extends to near the interior center of the storage tank 31 with a degree of inclination, and its lower side is curved and bent toward the inner wall 31b. On the other hand, there are two air intake ports 31d slightly above the center of the rear inner wall 31b.
During operation, external air is taken into the space P through a punched metal or cloth stretched over the intake port.

The stirring device 32 has a large number of blades 32b fixed to a rotating shaft 32a, and is rotated by the drive device 21. The screw feeder 33 has spiral blades 33 around a shaft 33a.
b, and the pitches of the blades 33b have three different pitches R, S, and T in the conveying direction of the powder and granular material. The reason why the pitch is changed along the axial direction in this way is to create a so-called mass flow state so that the shape of the powder and granules in the storage tank does not change at the surface level when being discharged. One side of the screw feeder 33 extends horizontally beyond the storage tank 31, and the extended portion extends beyond the storage tank 31.
It is surrounded by a discharge pipe 24 attached to the front surface of the tube (see Figure 2). Figure 4 shows a discharge pipe 24 with a circular cross section.
2, a slot-shaped powder discharge port 24a is formed near the tip of the discharge pipe 24.
This slot-shaped discharge port 24a has a width and length determined by the discharge amount determined by the rotation speed of the screw feeder 33 and the diameter of the discharge pipe 24, and is below the horizontal plane passing through the center of the discharge pipe 24. It is set up to be located at. The longitudinal direction of the discharge port 24a is parallel to the blade 33b of the screw feeder 33 housed inside the discharge pipe 24 for reasons to be described later.
It is set to intersect with

Next, the operation of the dispensing device according to the present invention will be explained.
When separating a predetermined small amount from the powder and granular material stored in the storage tank 31, first, the control panel 34 is operated to set a predetermined amount. Next, press the start portion button.
The drive device 21 in the metering device main body 2 is energized, the stirring device 32 and the screw feeder 33 begin to rotate, and the stirring device 32 supplies the powder to the screw feeder 33. At this time, the air taken into the storage tank from the air intake port 31d of the storage tank 31 due to the stirring passes through the space P as shown by the arrow and is drawn into the powder and granules being stirred, fluidizing the powder and granule layer. At the same time, it becomes homogenized, so screw feeder 3
The layer of powder and granules fed into the storage tank 3 is made uniform without being affected by the amount of powder and granules remaining inside the storage tank. Air drawn into the powder and granules being stirred is passed through the air intake port 31.
It is cleaned with a punched medal or cloth stretched over d. In this way Screw Feeder 3
As the shaft 33a filled between the spiral blades 33b rotates, the granular material fed into the storage tank 31 is conveyed from the storage tank 31 toward the discharge pipe 24, and reaches the discharge port 24a at the end of the discharge pipe 24. The change in the area of the powder and granular material at the discharge port 24a is determined by the screw feeder 3.
As 3 progresses step by step, it increases almost linearly with a small rate of change. As a result, the outlet 24
The change in the amount of powder discharged from a is relatively small. On the other hand, since the conventional outlet has a circular or rectangular shape, the rate of increase in the outlet area is non-linear and changes rapidly in the initial stage.
Changes in the amount of powder discharged from the discharge port are extremely large and discontinuous. From this, it can be easily understood that it is difficult to discharge a fixed amount using conventional dispensing devices. In this way, by forming the outlet into a narrow slot with its longitudinal direction intersecting the blades of the screw feeder, the rate of increase in the outlet area is made almost linear and gradual. As a result, changes in the amount of powder and granular material discharged from the discharge port can be made small and continuous. In order to further improve quantitative performance, it is preferable that the length of the slot in the direction of the discharge pipe be slightly longer than one pitch of the screw feeder. As an example, the diameter is 70 cm and the pitch is 7 cm.
In a dosing device using a screw feeder with a transport rate of 200 kg/hour, the width of the slot-shaped outlet is 1 cm and the longitudinal length is 10 cm.
As mentioned above, the axial length of the discharge port cannot be determined independently of the pitch, but its width and angle with respect to the axial direction of the discharge pipe or intersecting angle with the screw feeder blades can be arbitrarily determined. can. Also, the air intake port 3 formed on the rear wall of the storage tank
The area 1d is arbitrarily set according to the rotational speed of the stirring device and the screw feeder.

It goes without saying that the metering device of the present invention can be used not only for fine powders such as wheat flour but also for granular materials such as wheat grains, rice grains, and bread crumbs.

[Brief explanation of the drawing]

FIG. 1 of the accompanying drawings is a schematic diagram of a powder/granular material dispensing device according to the present invention, FIG. 2 is a schematic diagram showing the relationship between a storage tank, which is a main part of the dispensing device, and a powder/granular material conveyance/discharge system, and FIG.
The figure is a cross-sectional view taken along line A-A in Figure 2.
The figure is a perspective view of a powder discharge pipe. DESCRIPTION OF SYMBOLS 1... Measuring device, 2... Apparatus body, 21... Drive device, 22... Weight detection device, 23... Measuring device, 24... Discharge pipe, 24a... Discharge port, 3...
Quantitative supply device, 31...Storage tank, 31a...Charging port, 31b...Inner wall, 31c...Nose, 31d
... Air intake, 32 ... Stirring device, 32a...
...rotating shaft, 32b, 33b...blade, 33...screw feeder, 33a...shaft, 34...control panel.

Claims (1)

[Scope of Claims] 1. Amount of powder and granular material consisting of a storage tank for storing powder and granular material, an agitation device provided at the bottom of the storage tank for stirring the powder and granular material, and a discharge device that supplies the powder and granular material to a discharge port. In the device, an air intake port is provided approximately in the center of a side wall of the storage tank, and a nose extends from the side wall to near the interior center of the storage tank, and the air intake port is formed by the inner surface of the side wall of the storage tank and the nose. A dispensing device communicating with an internal space, the air taken in from the air intake port being brought into contact with powder and granular material being stirred through the internal space. 2. The discharge device is constituted by a screw feeder having a spiral blade, and the screw feeder is formed in a narrow slot shape having a longitudinal direction in a direction intersecting the spiral blade of the screw feeder. Dispensing device according to claim 1.