MX2008000983A - Apparatus for dispensing granular material and method thereof - Google Patents

Abstract

An apparatus for dispensing granular material, such as flux powder to a mold for continuous casting of metal, has an intermediate chamber, a dispensing hopper, and a conduit communicating the interior of the chamber to the interior of the hopper. The conduit has a rotatable auger running through its length, the auger reaching from within the interior space of the chamber into the interior hopper for transferring material from the chamber into the hopper. A dispensing line communicates with a bottom of the hopper at a transfer point for receiving material from the hopper and dispensing the material toward a dispensing end of the line. Pressurized air is supplied to the line, upstream of the transfer point, and a sealing cap is provided for actuating into sealing engagement with a hopper end of the conduit. A second inlet for pressurized air is provided such that air may be supplied directly into the hopper above the fill line. An automatic control processor links the various components, and provides for sequential operation. The material is conveyed batch-wise from the chamber into the hopper, and is not dispensed into the line until the chamber access has been sealed, thus preventing backflow into the chamber.

Description

APPARATUS FOR DISPENSING GRANULAR MATERIAL AND M ETHOD FOR IT BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an apparatus for storing, transporting and dispensing a fine powder. More particularly, the invention relates to an apparatus for use in dispensing a powder for molding or fluxing over a molten ingot being molded in a continuous casting operation. Description of the Prior Art In the steelmaking industry, particularly with respect to continuous casting operations, it is common practice to add a flux, in the form of a powder, on the molten ingot as it empties into the mold. Because the addition of the melting powder to the mold by the operator distracts the operator from the primary casting operation, it is desirable to automate the dispensing of the powder in the mold, or at least to provide a system that operates automatically with a simple operator command . The patent US 6474398 B 1 of Schoner et al. presents an apparatus for dispensing flux powder to a mold, comprising a source for granular flux for molding, a means for feeding and supplying the flux from an intermediate hopper to the upper surface of an ingot being molded. The delivery apparatus has at least one tube assembly, and conveys the flow in the manner of an air pump in the line. A flow rate mechanism, such as a pressure valve, is present, which varies the volume of air through the tube assembly, and thus controls the amount of flow delivered. The disadvantage of this system is that it is supported by an air pump in the line, such as a Venturi jet, as the only means of transport from the intermediate hopper. The molding flux is characterized by a high dust production factor, and this dust tends to clog and possibly deactivate the air pump in the line. Additionally, dust and particles can accumulate in the intermediate hopper, thus interfering with the continuous flow of flux into the mold. Patent US 4084626 presents an apparatus for automatic filling of containers according to net weight. The stations receive, in a transportable manner from the bulk tank, a dry, flowable, loose particulate material, the net weight of which is measured in a predetermined amount adjustable in a receptacle for net weight. The material is then dispensed in a vacuum vessel, such as a bottle. An assembly for bulk storage transport transfers the material from a bulk storage source to a separation chamber by means of a screw conveyor. The filling of the separation chamber is continuous and maintained at a constant level by means of a photoelectric level detector.

BRIEF DESCRIPTION OF THE INVENTION An apparatus for dispensing granular material, such as a flux powder, to a mold for continuous casting of metal, has an intermediate chamber, a dispensing hopper and a conduit that communicates the interior of the chamber with the interior of the chamber. hopper. The duct has a rotating worm that runs through its length, the worm reaches from within the interior space of the chamber inside the hopper to transfer material from the chamber into the hopper. A dispensing line communicates with the bottom of the hopper at a transfer point to receive material from the hopper and dispense the material towards a dispensing end of the line. Pressurized air is supplied to the line, upstream of the transfer point, and a sealing plug is provided to act in sealed engagement with one end of the hopper duct. A second inlet for pressurized air is provided in such a way that the air can be supplied directly into the hopper above the filling line. An automatic control processor links the various components, and provides sequential operation. The material is transported in batches from the chamber in the hopper, and is not dispensed in the line until the access to the chamber has been sealed, thus preventing the flow back into the chamber. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of the invention. Figure 2 is a schematic view of the invention. Figure 3 is a schematic view of a different embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION The invention will now be described with respect to the dispensing of a molding powder for use in continuous casting operations. However, it should be clear that the apparatus is independent of the casting operation itself, and therefore can be used to dispense any type of granular compound for any purpose. As shown in Figures 1 and 2, the powder is transported, preferably by gravity, through a conduit (1) to an intermediate chamber (2). The feed to the intermediate chamber (2) is more conveniently gravitationally taken from a drive hopper (3), which receives and maintains dust from a bulk source on its own, which is not shown. However, any means can be used to provide power to the intermediate chamber. The powder is transported in batches from the intermediate chamber (2) to a dispensing hopper (4), by means of a conduit with screw (6). The duct (6) is a tube that has a worm screw or rotary screw conveyor (8) therein. The duct (6) runs from one side (7) of the chamber, and opens into the dispensing hopper (4), preferably projecting (9) into the interior of the hopper, towards the center thereof to provide better distribution of the powder in her. The worm preferably runs from a point at the end near the hopper (9) of the conduit or near it, through the length of the conduit, and then into the interior (11) of the chamber, preferably extending laterally. through the interior to or near the opposite inner side (12) of the chamber. The worm is rotated by means of an external motor (10) and optionally by a steering shaft known in the art, for example, such as that presented in US Pat. No. 4,087,626. The lower part of the hopper (4 ) has a conical or other convergent shape for directing the powder by gravity in a dispensing line (14). The dispensing line leads to a dispensing end adjacent to the application area for the powder in the mold. Any suitable dispensing means can be attached to the end for applying the powder, such as a spray nozzle, manifold, etc. To transport the powder through the dispensing line towards the dispensing end, pressurized air is blown through the line towards the dispensing end. In order to avoid the problems of the prior art associated with the air pumps in the inlet line, an air pump (1 6) upstream of the location in which the bottom of the hopper in the opening is opened is provided. dispensing line (14). In order to avoid the additional problem of return flow, produced by the flow of pressurized air, return of the powder in the intermediate hopper and through the conduit in the chamber, a sealing mechanism is provided. A sealing plug (1 8), preferably in the form of a disk carrying a suitable sealing gasket, is formed to seal in a sealed manner against the end of the hopper (9) of the conduit (6). The sealing plug (18) resides in an activation arm (19) operated by an activation means (20). In the illustrated embodiment, the activation means is an air cylinder coupled to an air operated solenoid, which is activated electronically, preferably by a computer processor. The air cylinder is located externally to the hopper, with his arm reaching through the wall inside her, through a sealed opening that allows the arm to slide through it. The air cylinder extends the arm, pushes the plug to attach and seal the end of the duct. It can be seen that while an arrangement with air cylinder is convenient, any means to activate the sealing plug can be used. In addition to the upstream air pump (1 6), a means for supplying additional pressurized air in a preferred embodiment can be provided. This additional air supply is provided by means of an inlet (22) directly in the hopper, at a point on the filling line (described below). Once the conduit is closed by means of the sealing plug, the supply of pressurized air in the hopper, combined with the simultaneous supply of air by means of the pump upstream to the dispensing line itself, produces a continuous flow of dust out of the hopper and through the dispensing line. The additional air supply means to the hopper (22) also acts to prevent the return of powder flow from the dispensing line to the hopper. Of course, the return flow in the chamber is prevented by means of the sealing plug. A computer processor or other means of electronic process control (26) is provided to coordinate the various actions of the apparatus. Computer software is provided to operate the various parts of the apparatus, and to control the programming and sequence. An automatic filling detector (24), such as a photoelectric level control shown in US Patent 4084626, is provided in conjunction with the hopper. This type of device acts to detect a preferred level of powder within the hopper, and can be any suitable device. The filling line is chosen as a vertical point at the bottom of the end of the duct or below it. When the filling line is reached, the detector (24) sends a signal to the control means (26). The control means (26) then sends appropriate signals, sequentially, and preferably in close succession: towards the worm motor to stop the turning operation, towards the activating means of the sealing plug to seal the end of the conduit, and towards the upstream air pump and the air supply medium to the hopper to begin supplying air in order to transport the powder through the dispensing line. When the detector (24) or the second detector detects that the hopper has been emptied of powder, or that the dust supply has decreased to a certain threshold level, a signal is sent to the central processing unit (CPU), to reverse the instructions and previous operations. The air pumps are disengaged, the sealing plug is removed, and the endless screw resumes the rotation. An additional embodiment is described, wherein several apparatuses may be attached to a common energy source in order to serve several casting molds simultaneously. As shown in Figure 3, a second chamber of a second apparatus is located below a first chamber of a first apparatus. The first and second apparatuses are essentially identical, and of course, more apparatuses can be linked in a similar way. The first chamber opens in its lower part to gravitationally feed the second chamber. Due to the unique arrangement of the invention, by which the return of dust flow is avoided, a multiplication of apparatuses, linked by means of the cameras, can be provided, making sure that a damage in one installation will not affect the others. The chambers of the various apparatuses may be linked in other ways, although for the above reasons it is preferred to avoid pneumatic bonding. If it is necessary to link multiple cameras located in a horizontal plane, in such a way that the transfer by gravity of the feeding is not possible, a conduit with worm screw can be used to communicate the chambers, located in such a way that it does not interfere with the worm conduit of the first chamber communicating with the hopper. Those skilled in the art can realize that other gravitational or mechanical means can also be used to link multiple chambers. In addition to the apparatus described above, the invention also covers a method for dispensing granular material according to the steps indicated above, which preferably are performed in conjunction with said apparatus. In particular, the method for dispensing granular material comprises the following steps, in order: (a) to provide granular material in an intermediate chamber, (b) to transport the material from the chamber to a dispensing hopper through a conduit by means of a rotating worm screw, (c) sealing the conduit, (d) transporting the material from the hopper to the dispensing line, (e) dispensing the material through the dispensing line towards a dispensing end thereof by means of of pressurized air supplied to the line, upstream of a transfer point between the hopper and the line. In a preferred embodiment, the method also comprises providing pressurized air to the interior of the hopper on a material filling line, simultaneously with the step (e). A step (b) (!) Can also be provided between steps (b) and (c), which is the step of discontinuing the transport of material according to step (c). This step (b) (i) is preferably carried out after detection of the filling level of the material up to a predetermined threshold. As discussed in connection with the description of the apparatus, the method also provides a sequential link of steps, preferably by means of an automatic control processor. Accordingly, the material is transferred from an intermediate chamber to a dispensing hopper by means of a rotating worm, driven by means of a steering motor. When it is detected that the filling level is at a certain predetermined level, the steering motor discontinues the rotation of the worm, preferably this is done automatically by means of a signal sent from the filling level detector, although certainly the detection The level and operation of the motor can be done manually as well. Immediately after cessation of the rotation of the worm, the conduit connecting the chamber and the hopper is sealed, again preferably through an automatic means, such as a pneumatically activated air cylinder and piston arrangement, for example by middle of a solenoid. The activation step is preferably initiated by a signal associated with the fill detection level. Immediately after the sealing step, air pressure is provided to the dispensing line, which is in fluid communication on its own with the hopper. The air pressure, applied at the transfer point, and preferably additionally inside the hopper, is also preferably activated by a processing signal. When it is detected that the level of the material in the hopper is at a predetermined low or empty level, or for example after a predetermined period of time, the process steps are reversed. The air pressure for the dispensing is discontinued, the seal is removed from the duct, and the worm rotates again to bring new material to the hopper.

Claims (9)

1 . An apparatus for dispensing granular material, comprising: an intermediate chamber, a dispensing hopper, a conduit that communicates the interior of the chamber with the interior of the hopper, the conduit has a rotating worm that runs through it, the endless screw reaches from inside the interior of the chamber to the inside of the hopper, to transfer material from the chamber into the hopper, a dispensing line that communicates with the bottom of the hopper at a transfer point to receive material from the hopper and to dispense the material towards a dispensing end of the line, a first means for supplying pressurized air to the line, upstream of the transfer point, a sealing plug to be activated in sealed engagement with a end of the duct in the hopper. The apparatus of claim 1, further comprising a second means for supplying pressurized air in the hopper, above a predetermined upper fill level.

3. The apparatus of claim 1, further comprising means for activating the sealing plug.

The apparatus of claim 3, further characterized in that the means for activating the sealing plug comprises a piston arm connected to the sealing plug, the piston arm is connected to a piston that resides within a cylinder.

5. The apparatus of claim 4, further characterized in that the cylinder and the piston comprise an air cylinder that resides externally of the hopper, and the piston arm passes through the wall of the hopper by means of a sealed opening. The apparatus of claim 1, further characterized in that the conduit and the worm that is inside it extend into the interior of the hopper. The apparatus of claim 1, further comprising a fill level detector for detecting when a level of material in the hopper reaches certain predetermined levels. The apparatus of claim 7, further comprising an automatic control processor linked to the fill level detector, a worm motor that rotates the worm, a first air pump that provides pressurized air to the dispensing line, and an activating means for activating the sealing plug against the end of the conduit. The apparatus of claim 8, further characterized in that the control processor comprises means for receiving a signal from the fill level detector indicating that the material in the hopper has reached a first predetermined fill level, means for sending a signal to the worm motor to stop the rotary movement of the end screws, means for sending a signal to the activating means to activate the sealing plug in a sealed coupling against the end of the conduit, means for sending a signal to the first medium for supplying pressurized air to begin supplying pressurized air to the dispensing line, means for receiving a signal from the filling level detector indicating that the material in the hopper has decreased to a second predetermined filling level, means for sending a signal to the first air pump to stop providing pressurized air, means to send a signal p for activating means for removing the sealing plug, and means for sending a signal to the worm motor so that it begins to rotate the worm. The apparatus of claim 9, further comprising a second means for supplying pressurized air in the hopper on a predetermined upper fill level, the second means is linked to the processor, and a means for sending signals to the second means to supply pressurized air that matches said signals that are being sent to the first medium to supply pressurized air. eleven . A method for dispensing granular material, comprising the following steps, in order: (a) to provide granular material in an intermediate chamber, (b) to transport the material from the chamber to a dispensing hopper through a conduit by means of a rotating worm screw, ( c) sealing the conduit, (d) transporting the material from the hopper to the dispensing line, (e) dispensing the material through the dispensing line towards a dispensing end thereof by means of pressurized air supplied to the line, upstream of a transfer point between the hopper and the line. The method of claim 1, further comprising providing pressurized air inside the hopper on top of a material filling line, simultaneously with step (e). The method of claim 1, further comprising a step (b) (i), between steps (b) and (c), of discontinuing the transport of material according to step (b). The method of claim 1, further comprising a step of detecting a material fill level in the hopper and sending a signal to perform step (b) when the fill level reaches a predetermined level.