Patent ID: 12252800

DETAILED DESCRIPTION

The present disclosure is directed toward hardware that is useful for processes that require the intimate mixing of solid materials or parts, and liquids. These processes may include barrel plating, leaching, extraction, passivation tumbling, dyeing and the like. A common aspect of these processes is the need to provide access of a liquid solution to a quantity of solid material or parts in such a way that fresh reactants in the liquid phase are mixed with the solids, and/or reaction products or byproducts are carried away from the solids. It is normal in many of these processes to transport a container containing the solid material or parts to a tank filled with liquid, and to use the container to hold the solids and to promote the mixing of the solids and the liquid. In some cases, it may also be necessary to provide additional energy to the container, such as providing an electrical voltage in the case of barrel electroplating to cause the deposition of metallic ions onto the parts as a metal film or coating. It is useful during these processes to allow fresh chemistry to enter the container during processing, and to allow used or spent chemistry to exit the container in order to promote the rate of chemical or electrochemical reactions taking place. The container may then be moved to a rinse tank where a rinsing solution such as water flows through the solids in order to remove any additional chemistry from the solid material or parts. While a basket that holds the parts as they are transferred from one tank to the next may be used in some cases, this disclosure is directed more to the cases where a barrel or drum holds the parts and is rotated during processing in order to enhance the agitation and intimate mixing of the solid material and liquids contained within.

Conventional devices utilize containers or barrels with perforations to allow access of solution to the interior of the container. In some cases, the end of a specialized barrel may also be open in order to allow solution access. These devices usually include a means for providing rotation in order to promote mixing of the solids and liquids, and could also provide features such as baffles on the interior of the container to promote mixing and agitation of the solids inside the container.

Conventional systems use perforations that are smaller than the parts being processed in order to contain the solids inside the barrel, and may employ devices such as screens to provide structure and fluid access while minimizing the hole size through which solids could exit the container. A problem arises, however, when the solids consist of a mixture of part sizes or particle sizes, especially in cases where the solid material has been produced by some kind of a crushing or milling operation. In such a case, there will be a range of sizes of the solid material, and it is difficult to provide a hole or screen size that will not allow any of the solids to fall out of the container. In such a situation, it may be necessary to screen the incoming solid materials and process the fine solids differently than the coarser solids, or to choose a different type of processing apparatus.

In addition, when perforations in the container sidewall are oriented perpendicularly to the sidewall and the axis of rotation, the only convective processes that enhance solution transfer across the smallest diameter pore, or perforation, are those caused by vortices due to viscous shear of the solution due to the relative velocity of the container and the solution near the perforation or hole in the container or screen.

The present disclosure describes a container (or barrel)100which provides for enhanced solution flow into, and through, the container (or barrel)100, while at the same time not compromising the ability of the container100to hold solid material within an interior102of the container100, even if the solid particle size is small or varying, such as in the range of 5 microns to 2 inches in diameter. The present disclosure accomplishes this by utilizing features that help to direct fluid into the container100as it rotates, which promotes the solution flow into the container100at the sidewalls104. An exemplary embodiment of the container is shown inFIG.5A, and is designed as an obliquely oriented barrel100with an open end106, which allows for the exit of spent or used solution from the upper open end106of the container100. This embodiment of the container100of the present disclosure is able to overcome the problems mentioned above through a unique design of slots108(or perforations) within the sidewalls104of the material container100. The slots108are are designed to promote the flow of solution from the outside of the container100to the inside102of the container100as the container100is rotated within the liquid110in the tank112in the exemplary system for processing solid material shown inFIG.4. The slots108are designed with a component of their shape (a leading edge) substantially aligned with the direction of rotation A and tapered to allow fluid to be easily drawn into the slots (or grooves)108, and another component (a trailing edge) of their shape designed to “scoop” the fluid from the exterior to the interior of the container. This design causes the rotation of the container to increase the pressure in the fluid at the exterior of the container100at the interior wall penetration area to cause fluid to enter the container through the slots (perforations)108. The design of the slots108in the container wall are like trenches, or veins, that allow easy access of the fluid to the trench, which is below the exterior surface of the container, with “scoops” at the trailing edge that help to push the fluid to the interior of the container. The liquid compresses and behaves as if pressurized so liquid flow is directed into the container through the slots and then out of the container through the open end of the container. This design causes the rotation of the container itself to act as a pump to transfer fluid from the exterior of the container to the interior near the sidewalls. Of course, there must be an exit path as well to allow solution flow. This exit path can be near the rotation axis of the container, at one or both ends. In the embodiment ofFIG.5A, the exit path is at the open end106of the container100. This design acts to draw fluid in at the outer circumference of the container as the container100rotates, and push it out near the axis of rotation. This flow is the reverse of that in a conventional centrifugal pump. The container100may preferably be designed with a multitude of such slots108to provide solution flow into the container100. It will be recognized that the number of slots108may be chosen to optimize the amount of fluid flow into the container100, while not compromising the structural integrity of the container100.

FIG.5Bshows an embodiment of a container200having an upper open end206and a closed base207. The container200includes slots (perforations)108defined in a wall204of the container200. A gear210is secured to the closed base207to allow a motor to drive the rotation of the container200about the longitudinal axis of the container extending between the closed base207and the open end206of the container200.

FIG.6shows a sectional view of an embodiment of the disclosure that shows one design of a slot108that can be used to provide fluid flow into a container100. The slot extends from an outer surface114of the wall104to an inner surface116of the wall104.

One way to make the grooves and holes in the surface of the container is to simply drill holes in the sidewall104of the container100in an orientation that is almost tangential to the exterior surface of a substantially cylindrical container. By drilling holes with a slight angle to the tangent to the exterior surface114, grooves may be formed in the exterior surface114of the container100, which lead to a scooping feature where the holes penetrate the container wall104, as seen inFIG.7. Additionally, the holes will be such that the solid material inside the container100will traverse the leading edge120so as to fall to the trailing edge122of the holes if the container is rotated in the proper direction. This will minimize the chances of solid material exiting the container through the holes as the container is rotated. Furthermore, the cross sectional area of the portion of the holes that penetrates to the interior of the container may be made smaller than the cross sectional area of the holes at the exterior of the container, in order to provide nozzle-like features where solution enters the interior of the container. This may be done by using a tapered drill bit, or by drilling smaller penetrating holes in larger holes which do not penetrate through to the interior of the container. In this way, the pressure may be increased at the exterior portion of these nozzles, which will help to cause solution flow from the outside to the inside of the container.FIG.7shows the leading edge120tapered towards the trailing edge122. A re-entrant profile B of fluid entering the container100is shown as passing through the small opening124defined on the inner surface116of the wall104between the leading edge120and the trailing edge122of the slot108.

Therefore, one embodiment of the present disclosure is a barrel or drum100with slots (holes or perforations)108bored at an oblique angle such that they are almost on a tangent to the circumference of the container. The holes108penetrate the container wall in such a way as to provide elongated slots on the exterior surface of the container, with walls at their trailing edge (as the barrel rotates) that are dimensioned and configured to scoop fluid into the holes penetrating to the interior of the container. Preferably, the cross-sectional area of the holes that penetrate the interior wall of the container are smaller than the cross-sectional area of the holes that penetrate the exterior wall of the container. It is not necessary to drill the holes at an angle that is exactly perpendicular to the axis of rotation. In some embodiments, the holes are pitched at an angle of five or ten degrees, or even 20 degrees from perpendicular to the axis of rotation. In a further variation on this embodiment, it may be preferable to design the penetrations to the interior of the container in such a way that as material slides or tumbles around the interior of the container when the container is rotated, it cannot fall out through the penetrations directly to the exterior of the container. That is to say that if a line is drawn from the axis of rotation perpendicular to the sidewall of the container through any part of a penetration of the interior sidewall, it does not pass completely through to the exterior of the container. The angle of the holes is designed such that material would fall through a penetration of the interior sidewall to land on the sloped portion of the hole in the sidewall, where it would come back to the interior of the container as the container continues to rotate.

Referring now toFIG.8, in another aspect of the disclosure, it is desirable to have the penetrations of the interior sidewall of the container formed as long, narrow holes or slots308formed in the container wall304, in order to allow for sufficient cross-sectional area of the slots308to allow a reasonable amount of fluid flow into the container, while still limiting the ability of the solid material or parts in the container to fall out through the holes. In this case, the width of each hole penetrating to the interior, which is oriented substantially perpendicular to the direction of rotation, is kept sufficiently small to not allow the solid material or parts inside the container to fall out through the slot. The corresponding embodiment of the disclosure has narrow slots opening into the interior of the container (barrel or drum), with a shallow slope to the exterior of the container on their leading edge, and a bluff or scooping feature on their trailing edge. In this manner, fluid from the exterior of the container is scooped into the interior of the container as the container is rotated. In this embodiment, the container acts similarly to a squirrel cage fan, but with the fluid flow in the reverse direction. Accordingly, the fluid is drawn into the container at its outer edge, where it is allowed to mix with the solid material inside the container, before it exits the container near its axis of rotation. The container acts as a pump impeller, with the solid material or parts contained inside. The small slot penetrations to the interior of the container, along with the scooping feature provides a nozzle-like increase in pressure just exterior to the entrance to the interior of the container, which drives the flow of fluid toward the interior.

In a further variation on this embodiment, it may be preferable to design the penetrations to the interior of the container in such a way that as material slides or tumbles around the interior of the container when the container is rotated, it cannot fall out through the penetrations directly to the exterior of the container. That is to say that if a line is drawn from the axis of rotation perpendicular to the sidewall of the container through any part of a penetration of the interior sidewall, it does not pass completely through to the exterior of the container. The angle of the holes is designed such that material would fall through a penetration of the interior sidewall to land on the sloped portion of the hole in the sidewall at the trailing edge, where it would come back to the interior of the container as the container continues to rotate.

In another embodiment of the disclosure, the two aspects outlined above are combined, in order to provide a more efficient device for directing and controlling the solution flow into the container, while minimizing the opportunity for solid material or parts to come out of the container. In this embodiment, grooves are provided on the exterior surface of the container to allow the solution to be entrained in the grooves as the container is rotated. The grooves are substantially aligned with the direction of rotation near their leading edges in order to make it easy for the fluid to enter the grooves and flow at a velocity near the relative velocity of the outer wall of the container. The grooves are designed so as to curve such that their trailing edges become substantially perpendicular to the direction of rotation, where they open into the interior of the container through long, narrow slots. This embodiment allows the use of the grooves to help entrain and control the flow of fluid on the exterior of the container, while also providing the advantages outlined above relative to having narrow slots to direct flow of fluid to the interior of the container. The curvature of the grooves as they transition from being aligned with the direction of rotation at the leading edge to being perpendicular to the direction of rotation at the trailing edge, is designed so as to allow efficient solution flow as the fluid is directed along the curvature of the grooves from the leading edge to the trailing edge. As in the embodiments described above, the slots may preferably be designed to have a transverse dimension smaller than the transverse dimension of the outer portion of the grooves, in order to provide a nozzle-like feature, which serves to increase the fluid pressure just outside of the slots that penetrate to the interior of the container. The sidewalls of the slots may also be tapered so as to not allow solids to fall out of the container.

In yet another embodiment of the disclosure, it is desirable to use the container as part of an electrochemical process such as barrel electroplating, or barrel plating. In a barrel plating process, metal parts are typically placed into a barrel such as that indicated inFIG.4and moved to a tank of electroplating solution, as is well known in the art. It may be desirable to immerse the barrel containing its load of parts in a pretreatment tank and/or a rinse tank prior to immersion in the electroplating solution. Once the barrel with its load of parts is immersed in the electroplating solution, an electrical potential may be applied between the barrel and its parts and an anode, as is commonly used for plating processes. The electrical potential may be applied by controlling the voltage, or by controlling the current flow between the electrodes.

In the barrel plating application, current is directed to electrodes inside the barrel, which come into contact with the metallic parts contained inside. The current may then flow through the parts that are momentarily in contact with each other to be spread among the parts where it can become available to supply electrons to the wetted surfaces to promote reduction of metal ions in the solution which are plated as metal on the parts. Since the parts are continually moving while they are being coated with metal, new surfaces are continually contacting other parts and becoming exposed to the plating chemistry. This action allows for a uniform metal deposition on all surfaces of small parts that can be plated inside the rotating barrel.

In order to direct the current to electrodes in the interior of the barrel, it is necessary to provide some method of making electrical connection to a bus bar. This is typically done by using a conductive hook that is capable of routing current from the bus bar to a cable or wire that is attached to the electrode inside the barrel. This electrode commonly takes the form of a “dangler”401which extends from the axis of the container near the open end of the container to its interior of the container, where the dangler401can make electrical contact to the parts that are inside the barrel at an electrode end402of the dangler401. These electrical connections and electrodes could take other forms while still utilizing the present disclosure to allow for enhanced fluid flow and replenishment inside the barrel. The present design is useful for improving the flow of fresh electroplating solution and maintaining the concentration of metal ions available to be plated. This may also allow the use of higher currents and faster plating rates which would make the plating process more efficient. It may also be recognized that a reversed current could be used to allow electrochemical etching or electropolishing of the parts inside the barrel with similar advantages to those described for electroplating.

In an embodiment of the disclosure, a container, or barrel, is provided to contain solid parts or material that is to be intimately mixed with a liquid in a material handling or chemical process. The container is preferably provided with an open end that allows it to be inserted obliquely into a tank of liquid and for liquid to quickly fill the submerged portion of the container. Additionally, the container is provided with features that promote the fluid flow of solution into the interior of the container as it is rotated about its own axis. These features are formed by cutting, molding, or otherwise producing curved trenches that penetrate the side of the container, with at least a portion of a wall defining the curved trench being tangential to the rotation of the drum.

Solid material or parts such as molded, die cast, or machined parts or material such as ore or organic material are loaded inside the container, and the loaded container is immersed in a tank of liquid that will be used for treating the parts or material. The substantially cylindrical container is rotated about its axis when the material is immersed in the solution in order to provide intimate mixing of the solids and liquids, and to generate fluid flow. The fluid flow occurs from the exterior sidewalls of the container to the interior sidewalls and out of the container at or near its axis of rotation at one or both ends. As such, the device allows for the processing of solid material with liquids within the interior portion of a pump impeller. After a sufficient amount of process time has passed the container is removed from the tank of solution and allowed to drain, then rinsed before unloading the solids from the container.

Referring now toFIGS.9A and9B, the material inside the container100will move in a direction D opposite to the direction of rotation E, relative to the container sidewall104. Fluid on the outside of the container will follow the path marked by the arrows labeled C. Therefore, the dimension of the penetration that will be important to the solid material is the distance between the leading edge and the trailing edge in the tangential direction at the interior surface116of the container wall104. The penetration at the interior of the container has been designed to decrease the probability of solids leaving the container by virtue of the fact that the leading edge of the penetration (relative to the solid motion) has a sharp edge that protrudes over a portion of the trench, and potentially over part of the opposite side of the trench, when viewed in a radial direction. Additionally, the probability of solid material coming out of the container is reduced by the momentum of the solution flow entering the container at these openings, which will tend to push the solids back inside the container.

Referring now toFIGS.10A and10B, another embodiment of a container400has a plurality of slots408, each slot408having a leading edge420and a trailing edge422. The container400rotates in the direction G, and fluid enters the container along the arrow F through the respective slot408.

Referring now toFIGS.11A and11B, a partial axial cross section of an embodiment of a slot508in which the leading edge520and trailing edge522do not overlap when viewed in the radial direction is shown inFIG.11A, and a partial axial cross section of an embodiment of a slot608in which the leading edge620and trailing edge622do overlap when viewed in the radial direction is shown inFIG.11B.

FIG.11Ashows a container having a cylindrical portion defined by a cylindrical wall504, which has an outer surface514and an inner surface516. A plurality of circumferentially spaced apart slots508are defined in the cylindrical wall504and extend from the outer surface514of the cylindrical wall504to the inner surface516of the cylindrical wall504. Each slot508of the plurality of circumferentially spaced apart slots is defined by a first edge portion (leading edge, first surface, first edge wall, or first edge side)520forming one edge of the slot and a second edge portion (trailing edge, second surface, second edge wall, or second edge side)522forming another edge of the slot. The first edge portion520extends at a first angle α with respect to a first radial line501from a center of the cylindrical portion to an outer edge505of the first edge portion520, and the second edge portion522extends at a second angle β with respect to a second radial line503from a center of the cylindrical portion to an outer edge507of the second edge portion522, the first angle α being greater than the second angle β.

The first edge portion520and the second edge portion522together define a first opening511on the outer surface514and a second opening513on the inner surface516, the first opening511being greater than the second opening513. A circumferential distance from the outer edge505of the first edge portion520to the outer edge507of the second edge portion522is greater than a circumferential distance from an inner edge of the first edge portion to an inner edge of the second edge portion at the second opening513.

In some embodiments, the outer edge505of the first edge portion520extends in a line that is aligned with an axial direction of the cylindrical portion of the container. In some embodiments, the outer edge507of the second edge portion522extends in a line that is aligned with the axial direction of the cylindrical portion of the container.

The geometry of the first edge portion520and the second edge portion522define a curved path for fluid to pass from the exterior of the container to the interior of the container.

FIG.11Bshows an embodiment in which the outer edge607of the second edge portion622is radially outward of part of the first edge portion620. The container includes a cylindrical portion defined by a cylindrical wall604, which has an outer surface614and an inner surface616. A plurality of circumferentially spaced apart slots608are defined in the cylindrical wall604and extend from the outer surface614of the cylindrical wall604to the inner surface616of the cylindrical wall604. Each slot608of the plurality of circumferentially spaced apart slots is defined by a first edge portion (leading edge, first surface, first edge wall, or first edge side)620forming one edge of the slot and a second edge portion (trailing edge, second surface, second edge wall, or second edge side)622forming another edge of the slot. The first edge portion620extends at a first angle α with respect to a first radial line601from a center of the cylindrical portion to an outer edge605of the first edge portion620, and the second edge portion622extends at a second angle β with respect to a second radial line603from a center of the cylindrical portion to an outer edge607of the second edge portion622, the first angle α being greater than the second angle β.

The first edge portion620and the second edge portion622together define a first opening611on the outer surface614and a second opening613on the inner surface616, the first opening611being greater than the second opening613. A circumferential distance from the outer edge605of the first edge portion620to the outer edge607of the second edge portion622is greater than a circumferential distance from an inner edge of the first edge portion to an inner edge of the second edge portion at the second opening613.

In some embodiments, the outer edge605of the first edge portion620extends in a line that is aligned with an axial direction of the cylindrical portion of the container. In some embodiments, the outer edge607of the second edge portion622extends in a line that is aligned with the axial direction of the cylindrical portion of the container.

The geometry of the first edge portion620and the second edge portion622define a curved path for fluid to pass from the exterior of the container to the interior of the container. Because part of the first edge portion620and the outer edge607of the second edge portion622both lie along the radial line603, there is not a direct radial path for material positioned within the container to pass in a radial direction out of the container.

In some embodiments, the plurality of circumferentially spaced apart slots are arranged in axially spaced apart rows. In some embodiments, the slots are arranged in an array or a pattern on the container wall.

In some embodiments, the container has a closed second end, and a gear is secured to the closed second end.

In some embodiments, the container is formed with a cylindrical wall portion and a frustoconical wall portion connected to the cylindrical wall portion and located at the open end of the container.

In some embodiments, slots are defined in at least 5% of the container wall. In some embodiments, slots are defined in at least 10% of the container wall. In some embodiments, slots are defined in at least 20% of the container wall. In some embodiments, slots are defined in at least 30% of the container wall. In some embodiments, slots are defined in at least 40% of the container wall. In some embodiments, slots are defined in at least 50% of the container wall.

In some embodiments, at least one component of the shape of the slot is dimensioned and configured based on the rotational speed or other operational parameters associated with the container or associated with the system for processing solid material according to the present disclosure.

Advantages of the present disclosure relative to conventional designs for containers such as barrels and drums used in the barrel plating or leaching or etching industries, or metal or parts finishing industries, metal reclamation, or dyeing industries will be apparent to one of ordinary skill in the art. The present disclosure improves upon the fluid flow and mixing of fluid from the exterior of the container with solid material or parts inside the container by actively drawing fluid into the container as the container is rotated within the solution. This active enhancement of the fluid flow serves to aid in the replenishment of solution and any reactant chemicals it contains, while also enhancing the removal of reaction products and byproducts. This can help to speed up chemical reactions between the solid and liquid phases and make the process more efficient. The enhancement of solution flow into the container will also help to mix the solution more effectively with the solid material in the container.

An additional advantage of the present disclosure is that solid material or parts inside the container with the features described herein will be more effectively held within the container as it rotates in a tank of liquid, even if there is a range of solid sizes inside the container. The size and shape of the penetrations of the interior surface of the container have been designed such that they are small in the direction of rotation (or solid movement relative to the container walls) and preferably shaped so as to direct solids back to the interior of the container as the container rotates. For example, the penetrations can be configured to retain spherical solids that are in the range of 5 microns to 4 inches in diameter within the interior of the container as the container rotates.

A third advantage of the present disclosure is that the combination of the two effects described above further serves to prevent solid material from coming out of the container as it rotates. It will be apparent that the fluid flow from the exterior of the container to the interior of the container at its circumference will serve to entrain solids or push the solid parts into the interior of the container from the sidewalls, as the fluid flows from the circumferential surface toward the interior of the container. This momentum transfer from the fluid to the solid inside the container will help to improve the mixing of the solid inside the container, so that it does not simply slide along the exterior surface as the container is rotated. This will help to provide a uniform chemical process on all exposed surfaces of the solid parts due to superior mixing, as well as providing improved retention of the solid material inside the container.