JPH08126829A - Powder feeder - Google Patents

Abstract

PURPOSE: To quantitatively feed almost without weighing errors occurring in a powder quantitatively feeding device having a powder weighing hopper of small capacity below a powder feeding hopper of large capacity by fitting an air intake means having a filter communicating with open air on the ceiling surface of the powder weighing hopper. CONSTITUTION: When feeding powder, after the powder is first fed into a powder feeding hopper 3, a feeding port 2 is closed. Next, after a damper 5 is opened and a motor 12 is driven to rotate screw 10 and the powder is fed into a powder weighing hopper 7, a motor 12 is stopped and also the damper 5 is closed. Next, a feeding valve 20 is opened and a motor 16 is driven to feed the powder into the weighing hopper 7 little by little. The fed quantity is measured by a load cell 6, and when the measured quantity attains a prescribed one, the feeding valve 20 is closed to stop the supply. At this time, air is sucked into the powder weighing hopper 7 from an air intake means with a filter 14 to keep the inside of the hopper 7 at the same pressure as that of the atmosphere, thereby measuring errors do not occur.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of a device for feeding powder with high precision.

[0002]

2. Description of the Related Art Conventionally, in the case of supplying powder with high precision, an appropriate amount of powder is divided into small quantities from a large-capacity supply hopper to a small-capacity weighing hopper supported via a load cell. A method was adopted in which a powder provided in the bottom trough of the weighing hopper was cut out while subtractively weighing the subdivided powder. However, according to this method, there is a problem that a measurement error occurs as the amount of powder in the weighing hopper decreases. The present invention has been made in view of the above problems, and an object of the present invention is to provide a device that can supply powder without error when cutting powder from a weighing hopper.

[0003]

[Means for Solving the Problem] The inventors of the present application repeated experiments to find out the cause of the above-mentioned weighing error, and as the powder was cut out from the powder weighing hopper, the inside of the weighing hopper became negative pressure and the bellows. It was found that they have a function of pulling up the whole weighing hopper by sucking and contracting. From this, it was made as a result of studying to prevent the negative pressure in the weighing hopper caused by the cutting of the powder and to always maintain the atmospheric pressure state. In order to achieve the above object, the powder supply device according to the present invention is a screw which is rotatable by directly connecting one end to a motor and pivotally supporting the other end in a trough extending horizontally at the bottom. A powder supply hopper having an attached shaft and a discharge port with a damper provided at the lower end of the other end of the trough, and one end of which is directly connected to the motor in a trough extending in the horizontal direction at the bottom to enable rotation. A powder measuring hopper having a screw shaft and a discharge port with a cut valve at the other end of the trough, and a lower surface supported by a load cell; a lower end of the discharge port and the powder. A bellows which connects and communicates with the ceiling of the weighing hopper, and an intake unit with a filter which is provided on the ceiling of the weighing hopper and communicates with the outside air,
It is characterized by consisting of.

[0004]

Embodiments of the present invention will be described in detail below with reference to the drawings. A large-capacity powder supply hopper 3 having an input port 2 in the ceiling is provided above the trough 1 extending horizontally in the bottom part, and a damper 5 is provided in the discharge port 4 below the tip of the trough 1. Below -5, lower the bottom
A small-capacity powder weighing hopper 7 supported by the dosels 6 is provided, and an input port 8 provided at the ceiling of the powder weighing hopper 7 and a damper 5 discharge of the powder feeding hopper 3 are provided. The outlet 4 is communicatively connected by a bellows 9. Inside the trough 1 of the powder supply hopper-3, a shaft 11 with a screw 10 is connected to a motor 12 at its base end and is rotatably supported at its tip end by a bearing 13. There is. In addition, an intake means 14 with a filter having a mesh size smaller than that of the powder is attached to the ceiling of the powder weighing hopper 7, and one end is installed inside the trough 15 at the bottom.
A shaft 18 with a screw 17 connected to the motor 16 is rotatably provided. A cut valve 20 is provided in the vicinity of the discharge port 19 at a position slightly away from the tip of the shaft 18, and the cut valve 20 is electrically connected to the load cell 6 to instruct the load cell 6 to operate. Cut valve 2 by
0 is closed.

To actually supply the powder by the powder supply device, first, the powder supply hopper 3 is charged with an appropriate amount of powder, and then the charging port 2 is closed and sealed. Next, the damper 5 is opened and the motor 12 is driven to rotate the screw 10 together with the shaft 11 to send the powder to the left, and a predetermined amount is put into the powder weighing hopper 7, and the motor is moved. And the damper 5 is closed. Next, the cut valve 20 is opened and the motor 16 is driven to drive the powder measuring hopper-7.
The powder inside is cut out little by little, and the cut-out amount of the powder determined by the load cell 6 is measured. When the cut-out amount reaches a predetermined amount, the cut valve 20 is closed and the supply is stopped. At this time, since the level of the powder in the powder weighing hopper 7 decreases as it is cut out, the air trapped in the powder weighing hopper 7 is also discharged and reduced, but the powder from the filter-equipped intake means 14 is reduced. Atmosphere is sucked into the body weighing hopper 7 and is kept equal to the outside air pressure. Therefore, even if the powder level in the powder weighing hopper 7 is lowered by cutting out the powder, the inside of the powder weighing hopper 7 is always kept at atmospheric pressure. Therefore, measurement error does not occur.

[0006]

As is apparent from the above description, the present invention is a powder quantitative supply device having a small capacity powder measuring hopper below a large capacity powder supplying hopper, and a ceiling surface of the powder measuring hopper. Since the suction means with a filter that communicates with the outside air is attached to, the quantitative supply can be performed with almost no measurement error even when the powder is supplied with extremely high accuracy.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of an embodiment of the present invention.

[Explanation of symbols]

 3 powder supply hopper 5 damper 6 load cell 7 powder metering hopper 9 bellows 14 intake means 20 cut valve

Claims (1)

[Claims] 1. A trough (1) having a screw (10), which is rotatable by directly connecting one end to a motor (12) and pivotally supporting the other end, in a trough (1) extending horizontally at the bottom. 1, a powder supply hopper 3 having a discharge port 4 with a damper 5 at the lower end of the other end, and a trough 15 extending in the horizontal direction at the bottom, one end of which is directly connected to a motor 16 so as to be rotatable. Has a shaft 18 with a screw 17 and a cut valve 2 at the other end of the trough 15.
A powder weighing hopper 7 having a discharge port 19 with 0 and a lower surface supported via a load cell 6, and a lower end of the discharge port 4 and a ceiling portion of the powder weighing hopper 7 are connected to communicate with each other. Powder supply device comprising bellows 9 and filter-equipped suction means 14 provided on the ceiling of the weighing hopper 7 and communicating with the outside air.