Apparatus for handling fine bulk material

Apparatus including a support; first tubular conduit of gas impermeable material having open and closed ends providing an axially disposed passageway with at least one radial outlet; a second tubular conduit of gas permeable material encompassing and spaced from such first tubular conduit, having closed ends, providing a first annular passageway communicating with the radial outlet; a third tubular conduit of gas impermeable material mounted on such support, encompassing and spaced from such second tubular conduit, providing a second annular passageway having open and closed ends and having an inlet at such closed end, a helical member mounted coaxially on such second tubular member, and a device for rotating the first tubular conduit and method using same wherein air under pressure travels from the axially disposed passageway, through the radial outlet into the first annular passageway and through the gas permeable material into the second annular passageway.

FIELD OF THE INVENTION

This invention relates to an apparatus for handling fine bulk material and more particularly to an apparatus for conveying such material by means of an auger shaft at a steady and even flow rate.

BACKGROUND OF THE INVENTION

In the use of an auger in conveying fine bulk materials, it has been found that such usage results in an unsteady and uneven flow of materials, and even stoppage due to clogging. Such effects have been found to be caused by the accumulation and settlement of fine material particles in the spacing between helical flights which diminishes and possibly blocks the flow of material through the conveyance device. The result of such accumulation and settlement of material particles is a loss of capacity due to material accumulation diminishing the space between helical flights, and a reduction in the uniformity of the material being conveyed due to the detachment and discharge of segments of material lodged in helical flights. The deeper the spacing between helical flights, the greater the accumulation and settlement of material sought to be conveyed.

U.S. Pat. No. 8,011,861 to Sprouse and U.S. Pat. No. 1,258,911 to Kinyon show conventional connections for feeding air to into the open end of a hollow shaft to discharge through radial holes of the hollow shaft.

The rotary connection of the air supply in the U.S. Pat. No. 8,011,861 to Sprouse, illustration reference number156, is very similar in concept to commercially-available rotary unions. That is, it employs an internal bearing168, an internal seal176, a hollow shaft134&170and a stationary housing162not noticeably connected to the feeder and which is piped to a remote gas supply160. The only distinctions are (1) the auger shaft134extends into and comprises a part of the rotary connection rather than being externally coupled to it and (2) the bearing within the rotary connection appears to act as a support point for auger shaft134.

Kinyon (U.S. Pat. No. 1,258,911) describes the connection between the hollow auger shaft—illustration reference7—and the air supply conduit—reference12—as a “packed joint” reference13. Based upon the vintage of the patent, the described function of the “packed joint” and its name, it is apparent its “packed joint” is an arrangement also known to engineers and mechanical tradesmen as a “stuffing box” or “packing gland”. This class of rotary seal consists of a generally stationary housing which a shaft passes through. In the Kinyon patent, the stationary housing of packed joint13is rigidly attached to stationary air conduit12, which conduit ends near its attachment point to the packed joint. Rotating hollow shaft7is inserted into the stationary housing, through the follower and the packing material to end just short of contact with the end of air conduit12. The “packed j oint” employed by Kinyon is an adaptation of the ubiquitous packing gland.

Accumulation of powdered material between helical flights reduces the cubic feet per revolution capacity of an auger shaft and thus requires operating the feed mechanism at higher rotational speeds to attain the same feed rate when there is no such blockage. Accordingly, it is the principal object of the present invention to provide an apparatus for receiving, conveying and discharging a fine bulk material, utilizing a helical shaft for impelling such material in a continuous and uniform flow pattern.

SUMMARY OF THE INVENTION

The principal object of the present invention is achieved by an apparatus generally including a support; a first tubular conduit formed of a gas impermeable material journalled in such support, having one closed end providing an axially disposed passageway with at least one radial outlet; a second tubular conduit formed of a gas permeable material encompassing and spaced from such first tubular conduit, having closed ends, providing a first annular passageway communicating with the radial outlet of said first tubular conduit's axially disposed passageway; a third tubular conduit formed of a gas impermeable material mounted on such support, encompassing and spaced from such second tubular conduit, providing a second annular passageway closed at one end thereof, opened at a spaced end thereof and provided with an inlet at such one end thereof; a helical member mounted coaxially on such second tubular member, in such second annular passageway, between the closed and spaced outlet thereof; means for injecting a fluid under pressure into the first passageway and the radial passageway between the first and second annular passageways; and means for rotating the first tubular conduit.

Preferably, the third tubular conduit is provided with an inlet duct provided with a passage for funneling material gravity fed from an aligned bin into the second annular passageway, and an outlet duct communicating with the opposite end of the second tubular passageway into which material received through the inlet end thereof is be conveyed and discharged into the outlet duct, guiding such material into a conveyer duct, a receptacle or a bin. Material gravity fed into one end of the second annular passage and conveyed therethrough to the other end thereof by rotation of the first tubular member provided with the helical member, is prevented from accumulating and settling in the spacing between helical flights by air under pressure injected into and through the axial passageway of the first tubular conduit, one or more radial passageways in such first tubular conduit into the first annular passageway and through the interstices of the second annular conduit into the spaces between helical flights, precluding material from settling and accumulating therein. Such air further would function to fluidizing the conveyed material, facilitating its flow.

Referring to the drawings, there is illustrated an embodiment of the invention, generally including an assembly10for conveying a fine bulk material gravity fed from a vessel11and discharged into a conduit12. Assembly10includes an inner, tubular conduit13formed of an impermeable material, an intermediate tubular conduit14formed of a permeable material encompassing, spaced from and disposed coaxially relative to inner conduit13and an outer tubular conduit15also formed of an impermeable material encompassing, spaced from and also disposed axially relative to inner conduit13.

Inner tubular conduit13includes an axially disposed fluid passageway16, having one end as shown inFIG. 5extending through an opening in a side of conduit12and journalled in a mounting provided on an opposite side of conduit12, and an opposite end as shown inFIG. 6, provided with a stub shaft portion18having one end thereof extending into and closing an end of passageway16and an opposite end extending into and journalled in the housing of a gear reduction unit19, connected to the gear train of such unit, driven by a motor20mounted in the housing of the gear unit which could also be driven by a belt or roller chain drive.

FIG. 9is a partially open side elevational view of assembly10shown inFIG. 1with a portion removed to show the portion of the auger shaft indicated inFIG. 5to show the arrangement of the inner tubular conduit13and intermediate tubular conduit14within outer tubular conduit15.

As best shown inFIGS. 5 through 8, intermediate tubular conduit14cooperates with inner tubular conduit13to provide an annular passageway21closed at opposite ends by annular sealing components22and23, as best shown inFIGS. 7 and 8. Intercommunicating passageways16and21is one or more radially disposed passageways24as best shown inFIG. 7. Conduit14may be formed of a material sold by The Young Industries, Inc. of Muncy, Pa. under the trademark TRANSFLOW. Disposed on and secured to conduit14is a helical member25cooperating with inner and intermediate conduits13and14to provide an auger shaft functional to convey bulk particulate material within the flights thereof.

Outer tubular conduit15cooperates with intermediate tubular conduit14to provide an annular passageway including helical member25, preferably spaced from conduit15. As best shown inFIGS. 1 through 3, one end of conduit15is secured to a side of conduit12with the passageway between conduit13and14communicating with the interior of conduit12and an end of helical member25extending into the interior of conduit12, and the other end thereof is closed with a flange secured to and supported on a matching flange of the housing of unit19.

Mounted on one end of conduit15, adjacent unit19and spaced from conduit12is a duct26which communicates with the passageway between the intermediate and outer conduits14and15through an aligned opening in conduit15, as shown inFIG. 3, for gravity feeding a bulk particulate material into the annular passageway between the intermediate and outer conduits14and15, to be conveyed by helical member25to and discharged into conduit12. The upper end of funnel component26is provided with an annular flange27to which a compatible flange28of an elevated bin provided with a frusto-conically configuration section may be attached for gravity feeding material to be conveyed into outer conduit15.

Supported on assembly10is a pressurized air line30connected at one end to outer conduit15as at29and communicating with axial passageway16in conduit13via conduit17as at31for air to enter the open end of the axial passageway16, connected at a first intermediate location to outer conduit15and communicating with the annular passageway between conduits14and15as at32, communicating with the lower end of duct26as at33and connectable to a source of air under pressure by means of a connection end34.

In the operation of the assembly as described to convey bulk particulate material gravity fed from vessel11into conduit12, motor20is operated to rotate inner conduit13and intermediate conduit14with helical member25, and air under pressure is supplied to air line30. As the helical member is rotated, material fed through duct26into outer conduit15will be caused to be conveyed by helical member25and discharged into conduit12. As air under pressure is applied to air line30, such air will flow through, axial passageway16, radial passageways24, annular passageway21, through the interstices of intermediate conduit14and into the annular passageway between conduits14and15, providing a fluidizing layer of air between flights of helical member25. Such fluidizing layer of air between flights of helical member25functions to prevent the settlement and accumulation of material being conveyed thus providing a continuous and even flow of material being conveyed.

The continuous and even flow of material further is enhanced by injecting air under pressure through connector conduit33into duct26, fluidizing the material gravity fed into conduit15, thus enhancing an even flow, and by injecting air under pressure through connector conduit32into the outer side of conduit15, further fluidizing the material being conveyed by the helical member.

Any form of material holding and/or conveying device including vessels, bins, conduits and the like may be used to feed material into assembly10, and any such device may be used to receive material conveyed by such assembly.

From the foregoing detailed description, it will be evident that there are a number of changes, adaptations and modifications of the present invention, which come within the province of those persons having ordinary skill in the art to which the aforementioned invention pertains. However, it is intended that all such variations not departing from the spirit of the invention be considered as within the scope thereof as limited solely by the appended claims.