JP2000095213A - Powder feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a powder feeder capable of handling a powder which can not be handled by a large feeder, and being miniaturized by providing the function of feeding a large volume of powder with a simple constitution. SOLUTION: A powder feeder is formed of an elastic material, a pinch valve comprises a first conduit 2 to form a passage for a powder and a nip means comprising a shutter 4, etc., to hold the first conduit 2, and the pinch valve is intermittently opened/closed by an air cylinder 6, pressure reducing valves 41, 42 provided therefor, a solenoid valve 43 and a timer TM. A cycle controlling means to control the opening/closing cycle of the pinch valve may be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder supply device, and more particularly, to a device for supplying powder to a small container such as a box or a bag.

[0002]

2. Description of the Related Art Conventionally, there has been provided an apparatus for transferring powder from a large-volume feeder such as a rotary valve or a screw feeder to a small container. For example, as described in Japanese Patent Publication No. 5-41528, the container can be filled with the powder by an extremely low-speed air flow without causing disturbance of the powder in the container. An apparatus capable of preventing a body from being carried away from a container is disclosed as a powder transfer apparatus.

As shown schematically in FIG. 1, for example, a first conduit 2 extending from a large-volume feeder composed of a rotary valve 32 or a screw feeder 33 to the container 22 and the first conduit 2 An expanding annular body 21 made of an elastic material which is arranged around an end and can be made airtight with the wall of the container 22 and a powder 3 stored in a hopper 32a or 33a of the mass feeder. First conduit 2
An exhaust blower (not shown) that has an exhaust port 20 in the container 22 for allowing air to flow out of the container 22 when transferred from the container 22 to the container 22, and suction means for assisting the outflow of the outflow air. Second conduit 14 communicating with
An orifice formed by an opening of an air control valve 15 which is located in a position very close to the outlet of the second conduit 14 for sucking an air flow by the suction means, and one end of which is connected to the atmosphere. A second conduit 1 through which the inlet 19 as the other end opens into the container 22
4 and a third conduit 18 arranged concentrically around the outer periphery 4.

A feed inlet 1 at the upper end of the first conduit 2 supplies the powder 3 from the mass feeder into the first conduit 2 made of a highly elastic material. The passage of the powder 3 via the first conduit 2 is controlled by tightening by a shutter 4 connected to a slide plate 5.
The sliding plate 5 is connected to a piston head that reciprocates horizontally in the air cylinder 6. The opening of the shutter 4 is adjusted by a limit switch 30 provided on the air cylinder 6.

[0005] Further, between the bracket 12 which is indirectly connected to the air cylinder 6 and the shutter 4, the first conduit 2 is squeezed, thereby forming a valve consisting of a nip which is compressed. . This is generally called a pinch valve. This pinch valve can be vibrated by a vibrator 11 as a vibrator, and such vibration is transmitted to the powder 3 near the pinch valve, and the powder 3 is controlled in fluidity and can easily flow. State is maintained.
Reference numeral 31 denotes a roller conveyor for carrying the container 22 in or out of the apparatus.

The above-mentioned pinch valve functions to supply a small amount of powder at the final stage of powder filling. As a general procedure for filling the powder, first, the pinch valve is fully opened, for example, and the large-volume feeder passes through the first inlet 2 through the first inlet 2 as shown by an arrow A by the large-volume feeder. Then, the powder 3 is supplied to the container 22 from the discharge end 13. Then, when the weight before quantification, for example, 90% of the set weight is reached, the pinch valve is closed once, and the amount necessary for the remaining small amount of supply is supplied, and then the mass supply machine stops.

[0007] Thereafter, the pinch valve is slightly opened, the vibrator 11 is operated, and a small amount is supplied. When the set weight is reached, the pinch valve closes and the weighing is completed. Thereby, high filling control accuracy is obtained.
The configuration for measuring the powder is not shown. The opening degree of the pinch valve is adjusted so that the limit switch 30 in the air cylinder 6 is in an optimum state for the powder to be handled.
Adjust by changing the position of.

[0008]

However, in the above-mentioned configuration, there is a problem that the powder cannot be used by the mass feeder which cannot be used. For example, powder such as an explosive may be ignited by frictional heat or the like in a mechanism for transferring the powder, such as the rotary valve 32 or the screw feeder 33. Further, easily meltable powder such as toner may be melted by the frictional heat. Further, powder that is easily worn may be worn by the mechanism. In addition, when handling sticky powder, the powder may adhere to the mechanism and cause clogging, and when the powder is a food such as flour, there is a risk of decay. Therefore, in such a case, the mass feeder cannot be used.

However, in order to cope with this, if a hopper is directly connected to the feed air inlet 1, the powder 3
Cannot be controlled, the powder 3 is rapidly supplied to the container 22 when the pinch valve is greatly opened,
Accurate weighing cannot be performed. On the other hand, if only the above-mentioned minute supply is performed, it is not possible to quickly fill the powder in the container 22 having a relatively large capacity.

In view of the above problems, the present invention has a simple configuration and has a function of supplying a large amount by itself, so that it is possible to handle powders which cannot be used by the above-mentioned large-volume supply machine. Further, it is an object of the present invention to provide a powder supply device that can be downsized.

[0011]

In order to achieve the above object, according to the present invention, a pinch valve is formed by a conduit made of an elastic body and forming a passage for powder, and nip means sandwiching the conduit. The powder is supplied by opening and closing the pinch valve intermittently.

Further, the apparatus is provided with opening control means for controlling the opening of the pinch valve. In addition, a configuration is provided that includes a cycle control unit that controls a cycle of opening and closing the pinch valve. Further, a fluidity control means for controlling fluidity of the powder passing through the conduit is provided.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a longitudinal sectional view schematically showing one embodiment of the present invention. The basic configuration is the same as that of the conventional powder transfer device shown in FIG. 1, but as shown in FIG. 2, in this embodiment, a large-volume feeder in the conventional powder transfer device is used. Instead, the hopper 34 is directly connected to the feed intake port 1. Also, the limit switch 30 provided on the air cylinder 6 has been removed. In the present embodiment,
By driving the air cylinder 6 by the pneumatic control method, the pinch valve is opened and closed at a predetermined opening degree and cycle, so that the powder 3 stored in the hopper 34 is transferred to the container 22 through the first conduit 2. Supply and fill.

FIG. 3 is a diagram showing a pneumatic circuit for performing the pneumatic control. In the figure, the first conduit 2,
The shutter 4 and the air cylinder 6 are schematically illustrated. Reference numerals 41 and 42 denote pressure reducing valves, which are provided on paths (referred to as paths a and b, respectively) for supplying air to the air cylinder 6 in the direction of opening and closing the pinch valves, and serve to set the air pressure. Reference numeral 43 denotes an electromagnetic valve which cuts off a path (path a) for supplying air in a direction to open the pinch valve and switches conduction.
The switching is performed intermittently in a predetermined cycle according to a command from the timer TM. In addition, 40 is an air filter.

As shown in FIG. 1, compressed air supplied from a compressor (not shown) is supplied to pressure reducing valves 41 and 42 through an air filter 40. The compressed air having a predetermined set pressure by the pressure reducing valve 42 is always supplied to the air cylinder 6 through the path b in a direction to close the pinch valve. On the other hand, in FIG.
The electromagnetic valve 43 is switched to a side that shuts off a path (path a) for supplying air in a direction to open the pinch valve.
The compressed air having a predetermined supply pressure by the pressure reducing valve 41 is shut off by the electromagnetic valve 43. Further, the air cylinder 6 side of this path a is opened.

Therefore, in this state, compressed air is supplied to the air cylinder 6 only in the direction in which the pinch valve is closed, and this drives the piston in the air cylinder 6 to the left in the drawing, and the shutter 4 is connected to the first conduit. 2 and the pinch valve is closed. From this state, the timer TM
When the solenoid valve 43 is switched to the side where the path a is conducted, the compressed air having a predetermined supply pressure by the pressure reducing valve 41 is supplied to the air cylinder 6 through the path a in a direction to open the pinch valve. .

At this time, if the supply pressure of the pressure reducing valve 41 is adjusted to be higher than the set pressure of the pressure reducing valve 42, the shutter 4 moves to the right side in the figure, and the pinch valve opens,
Stop at the position where the pressures on the open and closed sides are balanced.
That is, by adjusting the supply pressure to the air cylinder 6 by the pressure reducing valve 41, the opening of the pinch valve can be adjusted. In this case, the opening increases as the supply pressure of the pressure reducing valve 41 becomes higher than the set pressure of the pressure reducing valve 42.

In the conventional powder transfer device, the limit switch 30 attached to the air cylinder 6 is used.
Although the position was changed and the opening was adjusted, the opening could not be adjusted during operation. However, in the present embodiment, the opening can be adjusted during operation. Further, by setting the pressure reducing valve 41 to be of a type capable of electrically adjusting the pressure, the opening can be adjusted by an electric signal. It is also possible to operate automatically and under optimal conditions without adjusting the opening.

As described above, the opening and closing of the pinch valve
The switching is performed intermittently by switching the solenoid valve 43 in accordance with a command from the timer TM.
In the present embodiment, the powder 3 is supplied once to the container 22 at a rate of about 0.8 to 1.0 sec. Generally, it is performed once every 0.5 to 2.0 seconds.
Adjustment of the supply amount of the powder 3 is performed by adjusting the opening degree of the pinch valve, and a stable supply is performed in an amount corresponding to the opening degree together with the effect of kneading and loosening the powder by the pinch valve itself. It can handle from large supply to small supply. At this time, if the vibrator 11 is used in combination, the powder 3 has more fluidity, and the powder 3 is smoothly supplied.

FIG. 4 is a graph showing the relationship between the pinch valve control pressure and the performance in the present embodiment as test data. The powder material used is 100 ~
It is sodium azide of about 200 μm, and has a bulk density of 1.0 g / cc. The pressure set by the pressure reducing valve 42 is 0.2 MPa (megapascal), and the cycle of opening and closing the pinch valve is once every 1.0 sec. The horizontal axis of the figure shows the change in the supply pressure by the pressure reducing valve 41 as a pressure reducing valve set pressure in units of MPA, and the vertical axis shows the supply capacity of the powder 3 in units of k.
g / hr.

As shown in FIG. 2, when the supply pressure of the pressure reducing valve 41 slightly exceeds 0.2 MPa which is the set pressure of the pressure reducing valve 42, the pinch valve starts to open, and
In the case of MPA, the supply capacity is about 4,000 kg / hr. The opening width of the pinch valve at this time is about 30 mm in the first conduit 2 having a diameter of 150 mm. Therefore, if the supply pressure by the pressure reducing valve 41 is further increased, it is apparent that the supply capacity is correspondingly increased. From this, it can be seen that according to the configuration of the present invention, it is possible to set the powder supply capability very widely.

The set value of the supply pressure may be changed continuously, or may be prepared in several stages, for example, for a large opening and for a small opening. still,
In the present embodiment, the air cylinder is configured to perform pneumatic control. However, the configuration is not limited to this, and a configuration in which a hydraulic control is performed by a hydraulic cylinder or a linear motion mechanism is controlled by a motor may be employed. Further, the material of the first conduit 2 is preferably an elastic body mainly composed of natural rubber, but is not limited to this natural rubber, and synthetic rubber, silicon rubber, or the like may be used if necessary. Is done.

The nip means referred to in claim 1 corresponds to the shutter 4 and the bracket 12 in the embodiment, and the conduit corresponds to the first conduit 2. The opening control means described in claim 2 corresponds to the pressure reducing valves 41 and 42 provided for the air cylinder 6 in the embodiment, and the cycle control means described in claim 3 corresponds to the pressure reducing valve 41 in the embodiment. Corresponding to the solenoid valve 43 and the timer TM provided for
The fluidity control means described in claim 4 corresponds to the vibrator 11 in the embodiment.

[0024]

As described above, according to the present invention,
By having a simple configuration and having a large-volume supply function, it is possible to provide a powder supply device that can handle powder that cannot be used by a large-volume supply machine and that can be downsized. .

Further, since the width of the supply capacity that can be controlled is very wide, it is particularly effective for filling and supplying. For example, the same apparatus can be used for filling from a flexible container to filling a small bag. Further, cleaning of the powder contact portion is easy, and maintenance is also easy.

According to the second or third aspect, the powder supply capacity can be easily adjusted.

Further, according to the fourth aspect, the fluidity of the powder is increased, and the powder is smoothly supplied.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view schematically showing an example of a conventional device.

FIG. 2 is a longitudinal sectional view schematically showing one embodiment of the present invention.

FIG. 3 is a diagram showing a pneumatic circuit for performing pneumatic control.

FIG. 4 is a graph showing a relationship between a pinch valve control pressure and a capacity.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Inlet intake port 2 First conduit 3 Powder 4 Shutter 5 Slip plate 6 Air cylinder 11 Vibrator 12 Bracket 13 Discharge end 14 Second conduit 15 Air control valve 18 Third conduit 19 Inlet 20 Exhaust port 21 Annular body 22 container 34 hopper 40 air filter 41, 42 pressure reducing valve 43 solenoid valve TM timer

Claims (4)

[Claims] 1. A pinch valve is formed by a conduit made of an elastic body and forming a passage for powder, and a nip means for sandwiching the conduit, and the powder is intermittently opened and closed so that the powder is removed. A powder supply device characterized by supplying. 2. The powder supply device according to claim 1, further comprising an opening control means for controlling an opening of the pinch valve. 3. The powder supply apparatus according to claim 1, further comprising a cycle control means for controlling a cycle of opening and closing the pinch valve. 4. The powder supply device according to claim 1, further comprising a fluidity control means for controlling fluidity of the powder passing through the conduit.