EP1841653B1 - Device for filling a container with at least one type of powder material - Google Patents

Abstract

The device has an evacuation unit (14) comprising an air evacuation duct (16) permitting the evacuation of the air in a container or mold (6) when a powder material penetrates in the container or mold. An air evacuation duct (18) permits the air to exit the container or mold before starting a filling phase. A pneumatic pump (24) extracts the air contained in the container or mold during the filling phase. An independent claim is also included for a method for filling a container or mold with a powder material.

Description

TECHNICAL FIELD AND PRIOR ART

The present invention relates to a device for filling a container with at least one powder material.

Such a device is known for example from the document DE 33 10 725 .

The materials in the form of powder are very numerous, for example the detergents, milk powder or cement. In the industry, these are powder materials intended to be shaped, for example, by sintering, compression, compression-sintering or hot isostatic pressing. These are for example metal powders, ceramics or their mixture. It is possible to obtain pieces of very complex geometry.

However, it has been found that air present in the mold before filling is capable of rendering the filling inhomogeneous, causing porosities in the molded part, to lead to low and scattered apparent densities, and to lengthen filling times. In addition, the presence of air is likely to disturb the flow of the powder material into the mold.

The document US 2003/0113222 proposes a device for injecting air into the powdery material at the time of filling the mold in order to homogeneously distribute the different particle size of material. However, nothing is planned to overcome the problem of the air contained in the mold.

It is therefore an object of the present invention to provide a container filling device ensuring a homogeneous distribution of the powder material in the container.

It is also an object of the present invention to provide accelerated filling of the container.

STATEMENT OF THE INVENTION

These objects are achieved by a filling device provided with at least one ventilation duct of a mold intended to be filled by means of said device.

In other words, before filling and / or during filling, ducts are provided to allow air to escape from the mold and to leave room for the powder, or to be sucked out of the mold, a slight suction speeding up the filling is then generated.

The main subject of the present invention is a device for filling a container with at least one substance in powder form, said device comprising a filling channel intended to bring the material from a stock of material to an inlet orifice of the container characterized in that also comprises means for discharging a pneumatic fluid contained in said container.

In particular, the evacuation means comprise at least one duct intended to connect the inside of the container to an environment outside the container during the filling phase, said first duct and / or a duct intended to evacuate the air before filling. , said second conduit. Advantageously, the second exhaust duct connects to the first duct.

In a preferred embodiment, the first discharge duct is internal to the filling channel.

Advantageously, a suction means of the air contained in the container is connected to the first and / or second conduit.

In a first exemplary embodiment, the suction means is a pneumatic pump.

In the case where the first discharge duct is internal to the filling channel, the first duct can be connected to the pump by at least two secondary ducts, advantageously three, distributed angularly in a regular manner around the first duct.

In a second exemplary embodiment, said suction means is mounted in the filling channel and is formed by at least one blade mounted on a lower face of a disk intended to be rotated about its axis, said disk comprising in its central part an orifice connected to the first discharge duct.

At least one powder material distribution member may also be provided in the container projecting from an upper face of the disk.

The filling device may also comprise a cylindrical core disposed axially below the plate and having a third discharge duct disposed in line with the first duct and opening into the upper part of the container by at least one secondary duct.

Advantageously, the device comprises a plurality of secondary conduits distributed angularly in a regular manner around the third conduit.

According to another exemplary embodiment of the filling device according to the present invention, the suction disk and a separate distribution disk of the suction disk and placed before the suction disk in the direction of filling of the material, are integral in rotation of a shaft adapted to be rotated and in which is performed the first vent pipe.

According to one embodiment, the filling device is in the form of a shoe for sliding on a table having an orifice connected to the inlet of a container.

The device according to the present invention is particularly intended to fill at least one mold for making parts by sintering, compression, compression-sintering or hot isostatic pressing.

The present invention also relates to a method of filling a container with at least one powdered material including the step of evacuating the air contained in the container during the introduction of the powder material and / or prior to the placement of said material.

BRIEF DESCRIPTION OF THE DRAWINGS

• La figure 1 est une représentation schématique d'un premier exemple d'un dispositif de remplissage selon la présente invention,
• la figure 2 est une représentation schématique du dispositif de la figure 1 dans une phase préalable au remplissage,
• la figure 3 est une représentation schématique du dispositif de la figure 1 en début de remplissage,
• la figure 4 une représentation schématique du dispositif de la figure 1 en fin de remplissage,
• la figure 5 est une représentation schématique d'un deuxième exemple d'un dispositif de remplissage selon la présente invention,
• la figure 6 est une vue en coupe d'un deuxième mode de réalisation d'un dispositif non couvert par l'invention,
• la figure 7 est une vue en perspective isométrique d'un détail de la figure 6,
• la figure 7a est une vue de détail de la figure 7,
• la figure 8 est une vue en coupe longitudinale d'un autre exemple du deuxième mode réalisation non couvert par l'invention.

The present invention will be better understood with the aid of the description which follows and the attached drawings for which the upper and lower parts are respectively the top and the bottom of the drawings.

• The figure 1 is a schematic representation of a first example of a filling device according to the present invention,
• the figure 2 is a schematic representation of the device of the figure 1 in a phase prior to filling,
• the figure 3 is a schematic representation of the device of the figure 1 at the beginning of filling,
• the figure 4 a schematic representation of the device of the figure 1 at the end of filling,
• the figure 5 is a schematic representation of a second example of a filling device according to the present invention,
• the figure 6 is a sectional view of a second embodiment of a device not covered by the invention,
• the figure 7 is an isometric perspective view of a detail of the figure 6 ,
• the figure 7a is a detail view of the figure 7 ,
• the figure 8 is a longitudinal sectional view of another example of the second embodiment not covered by the invention.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

On the figure 1 , we can see a first example of the first embodiment of a filling device according to the present invention comprising a shoe 2 said filling intended to slide along the arrow F on a table 4 in which are formed cavities 6 to fill, for example molds. The shoe comprises a filling channel 8 connected to a reserve of powdery material (not shown) by an upper end 7, the channel 8 opens into a lower portion 10 or soleplate intended to be in contact with the table 4, through a hole flow 12 through which the powder material flows into the container 6.

According to the present invention, the shoe also comprises means 14 allowing a pneumatic fluid contained in the container 6, for example air to be removed from the container. In the example shown, the means 14 comprise a first conduit 16 intended to allow evacuation of the air from the container 6 during filling, that is to say when the powder material enters the cavity.

The device also advantageously comprises a second evacuation duct 18 intended to allow the air to exit the container 6 before the beginning of filling ( figure 2 ). But it is understood that an evacuation of air only before filling or only during filling is not outside the scope of the present invention.

In the example shown, the first duct 16 is disposed inside the filling duct in a substantially coaxial manner so as not to hinder a uniform flow of the material in the duct 8. The first duct 16 opens out through a first lower end 22 in the flow orifice 12 of the channel 8. The second duct 18 is formed directly in the shoe and opens at a first end 20 in front of the end 22 in the direction of the arrow F, in the sole 10 of the shoe and by a second end 23 in the first conduit 16.

The position of the first duct inside the filling duct substantially coaxially with it, allows very advantageously to obtain an extraction of the pneumatic fluid having a symmetry of revolution. Indeed, the first suction duct 16 opens into a substantially central portion of the container, which allows to suck air throughout the container all around the duct, without favoring a particular area of the container.

This avoids the appearance of disturbance in the flow of the powder and therefore in the filling the mold. An even more homogeneous filling of the mold is then obtained.

In addition, this embodiment allows a simple adaptation of the filling device to different types of powder. Indeed, it may be desirable to modify the suction as a function of the particle size of the powder, by modifying the suction flow rate. Thus, it suffices to replace the first duct 16 with a first duct of larger section or smaller section, respectively to increase or reduce the suction flow. In the devices of the state of the art, in which the suction is effected by the outside of the filling duct, this modification is on the contrary heavy and restrictive.

The air is discharged through a second upper end of the first duct 16 out of the filling channel. In the embodiment shown, the duct 16 passes through the periphery of the channel or tube 8. Advantageously, the duct 16 is connected to the external environment by at least two secondary tubes arranged symmetrically with respect to the duct. the axis of the duct 16, so as to disturb as little as possible the flow symmetry of the powder downstream of the bifurcation of the duct 16. Preferably, there are three secondary tubes angularly distributed regularly at 120 ° or six 60 ° secondary tubes around the canal axis.

It is understood that one could provide a first and a second duct completely independent and connected to the external environment independently.

Advantageously, in order to extract the air contained in the container before and during filling, there is provided a pneumatic pump 24 connected to the upper end of the first conduit 16 and able to extract the air contained in the container. It is understood that it is possible to envisage a pump extracting air from the container only before filling, either by providing first 16 and second 18 completely separate ducts or by actuating the pump only prior to filling. The use of this pump has the advantage of accelerating the filling speed due to the suction generated by the pump inside the container.

The pump is advantageously connected to the first conduit 16 by means of a flexible hose, adapting to the movements of the shoe.

The pneumatic pump 24 generates, for example a depression of 10 ⁵ Pa, which is sufficient to obtain good flow performance without causing powder in the air extraction ducts.

Advantageously, in the embodiment comprising a pneumatic pump, it is possible to provide filters arranged at the lower ends 22 and 20 respectively of the first 16 and second 18 ducts, forming barriers for the powder material in order to avoid its suction through the ducts 16 and 18.

It is understood that a device comprising several ducts 16 and / or 18 for extracting air from the cavity to be filled is not outside the scope of the present invention.

We will now describe the process of filling a container 6.

On the figure 2 , the first end 20 of the second duct 18 is facing the container 6, the air contained in the container 6 is sucked and discharged to the outside.

The shoe continues to move in the direction of arrow F ( figure 3 ), the flow orifice 12 comes opposite the container 6, filling begins, the powder flows into the container. The first conduit 16 communicates with the interior of the container 6, the air is discharged either naturally (the air is expelled due to the arrival of the powder), or by suction.

On the figure 4 , the shoe has again moved in the direction of the arrow F, the flow opening will soon exceed the entrance of the container 6. The filling is soon completed.

When the flow port 12 has completely passed the container inlet, the filling is interrupted.

On the figure 5 a second embodiment can be seen in which the shoe 2 comprises a separate filling channel 8 and a separate air outlet duct 18, the duct 18 making it possible to evacuate the air before filling, when its lower end 20 is next to the cavity of filling. Advantageously, the exhaust duct 18 is connected to a pneumatic pump 24. The exhaust duct 18 forms the second duct as previously described.

On the figures 6 and 7 a first example of a second embodiment of a device in which the powder material is homogeneously distributed by rotating a part of the filling device can be seen.

The filling device according to the second embodiment comprises a cylindrical casing 101 intended to be disposed above a container to be filled (not shown) and forming a filling channel between a powder reservoir and the container. The device also comprises distribution means 100, arranged in the filling channel and formed by a plate 103 of axis X, intended to be rotated about this axis X. In the example shown, the disc is provided with an upper face 102 of at least one dispensing element 104 extending substantially radially on the plate, in the form of a rod. The rod 104 is intended to homogeneously distribute the powder provided by a hopper disposed above the filling device (not shown). It is understood that the element 104 may have any form suitable for dispensing the powder.

The device also comprises on a lower face 106 of the disk 103 at least one air suction pad 107 (in phantom) intended for to cause a vortex to evacuate the air contained in the container to be filled. The plate 103 is rotated by means of a shaft 108 of axis coaxial with the axis X in which is made a first extraction duct 116 of the air sucked by the scoop 107. An orifice 113 is practiced in the central part of the disk on the side of the lower face 106 to put in communication the space below the disk and the first conduit 116. Thus during the filling, simultaneously with the uniform distribution of the powder around the X axis in the mold, the air is sucked according to the path indicated by the arrows A.

In the example shown, the suction blade, has substantially the shape of a turbine blade adapted to generate a depression But it is understood that it can have different shapes.

The device according to the present invention also comprises a central core 109 having the shape of a regular cylinder axially disposed below the plate and also provided with a third suction duct 110 arranged in line with the first extraction duct 116, in order to suck up the air contained in the bottom of the container. The suction duct 110 in its lower part advantageously separates into several secondary ducts 112 angularly distributed regularly around the axis of the suction duct 110 so as to have a uniform air suction in the mold.

We will now explain the operation of such a device.

In a first step, the device is placed above the container.

In a second step, the disc 103 is rotated, in particular the blade 106, the air contained in the container is then sucked by the conduits 112, 110 and 109 in the direction of the arrow

In a third step, the hopper is opened so as to allow the flow of the powder charge that it contains, in the filling duct and in particular on the tray. Due to the rotation of the tray and the dispensing rod, the powder is ejected uniformly against the walls of the filling channel and falls into the container. Simultaneously with the filling, the air continues to be evacuated.

On the figure 8 a second example of the second embodiment of a filling device can be seen. Said device comprises a separate distribution plate 120 and a suction plate 103, the suction plate 103 being intended to be placed close to the filling orifice of the container 6 and the distribution plate 120 above the plate of the container. The two trays are connected in rotation to a shaft 122 adapted to be rotated about the X axis, and pierced with a first longitudinal discharge duct 116, opening at one end into a lower face of the suction disc 103 and another end in the external environment.

During a filling phase, the shaft is rotated, causing suction of the air contained in the container.

Then the material is poured onto the dispensing disc which distributes the material in the container, the suction disc continues to suck the air into the container.

In this embodiment, the first air discharge duct during filling and the second duct for exhaust air before filling are combined.

The present invention then has the advantages of leading to a better homogeneity of the filling of the mold. Thus, for an axisymmetric part, it ensures a better circumferential density distribution of the powder.

In addition, the device according to the present invention makes it possible to lead to reduced filling times compared to systems of known type. In mass production, the gain in time obtained during filling leads to significant productivity gains.

The present invention is also very advantageous in the case of filling with ultrafine powders. In fact, fine powders, such as micrometric powders of the Sm-Co type are difficult to manipulate using conventional filling systems, since the presence of air in the matrix disturbs the flow of the powder during its fall into the cavity to be filled.

The present invention leads to performances close to those obtained with a vacuum filling system. Now the implementation of the vacuum filling is not feasible in an industrial environment.

The present invention applies in particular to the filling of mold with a powder or a mixture of powders for the production of parts by sintering, compression, compression-sintering or hot isostatic pressing.

But it is understood that the filling device according to the present invention allows to uniformly fill any type of container with a material in powder form.

Claims (7)

1. Device for filling a recipient with at least one material in the form of a powder, said device comprising a filling channel (8) intended to bring the material from a reserve of material to an entry opening of the recipient and means (14) to evacuate a pneumatic fluid contained in said recipient, said means of evacuation (14) having at least one duct (16) intended to connect the inside of the recipient to an environment outside of the recipient during the filling phase, called the first duct, the first evacuation duct (16) being internal to the filling channel (8) and the means of evacuation comprising another duct (18) intended to evacuate the pneumatic fluid before filling, called the second duct.
2. Filling device according to claim 1, wherein the second evacuation duct (18) is connected to the first duct (16).
3. Filling device according to claim 1 or 2, comprising a means of aspiration (24) of the air contained in the recipient and connected to the first (16) and/or to the second (18) ducts.
4. Device according to the previous claim, wherein the means of aspiration is a pneumatic pump (24).
5. Filling device according to claim 4, wherein the first duct (16) is connected to the pump by at least two secondary ducts, advantageously three, distributed angularly in a regular manner around the first duct.
6. Filling device according to any of claims 1 to 5, the device having the form of a shoe (2) intended to slide on a table (4) comprising an opening connected to the entrance of a recipient.
7. Filling device according to any of the preceding claims intended to fill at least one mould in order to manufacture parts by sintering, by pressing, by pressing-sintering or by hot isostatic pressing.

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