Patent Application
20070289902
The advantages of this invention will become apparent upon consideration of the following detailed disclosure of the invention, especially when taken in conjunction with the accompanying drawings wherein:
The dedusting apparatus is known in the art. A description of the structure and operation of a dedusting apparatus and a compact dedusting apparatus can be found in U.S. Pat. No. 5,035,331 and in U.S. Pat. No. 6,595,369, both of which were issued to Jerome I. Paulson, the contents of each of these patents being incorporated herein by reference. Typical particulate material to be cleaned by the dedusting apparatus 10 is plastic pellets that are to be passed into an injection molding machine to form plastic components. Examples of plastic particulate material that can be cleaned of contaminate material by the dedusting apparatus 10 are polyester, acrylic, high density polyethylene, polypropylene, nylon, polycarbonates, styrene, and low density polyethylene. Other types of particulate material that can be cleaned in the dedusting apparatus 10 include glass particles and grain.
Referring to
The casing 11 is formed with a back panel 12, in which the clean air inlet port 20 and the dusty air discharge port 25 are located, and integral side, top and bottom panels that form a generally rectangular configuration. A removable front door 13 is connected to the remainder of the casing 11 by fasteners 13a to permit access into the wash deck apparatus 50 for service and maintenance thereof. An interior panel 14 oriented parallel to the back panel 12 and the front door 14 divides the casing 11 into a main housing 15 situated between the interior panel 14 and the front door 13 and an air flow passageway 16 situated between the back panel 12 and the interior panel 14. A separator panel 17 divides the air flow passageway into a lower clean air plenum 18 and an upper dusty air plenum 19, each of which being in flow communication with the respective clean air port 20 and the dusty air port 25.
The configuration of the wash deck apparatus 50 is in a double set, oriented back-to-back such that the first wash decks 52 are angled downwardly at an incline of approximately 30 degrees from the horizontal in opposing transverse directions. The second wash decks 55 are positioned beneath the first wash decks 52 so as to receive the flow of product particles therefrom, as will be described in greater detail below, and convey the product over an inclined surface that is also oriented at about a 30 degree incline relative to the horizontal. The first wash decks 52 are formed in a central diamond-shaped assembly that includes a lower deck member 54 associated with each of the first wash decks 52 and connected thereto by a generally vertically extending portion 53. The lower deck members 54 help define an air flow path that directs air transversely outwardly into Venturi zones 35 through which air is directed in a counter current flow to aggressively remove dust particles from the product.
Product to be cleaned is introduced into the housing 15 through the product inlet opening 30 at the center of the top portion of the housing 15. The magnetic coil 31 is positioned around the product inlet port 30 to introduce a magnetic flux field which covers the entire housing 15. Since the product flow needs to be divided equally between the back-to-back first wash decks 52, a divider 32 is positioned to split equally the product flow into two opposing transverse directions onto the first wash decks 52. A product inlet deflector 40 is positioned at the product inlet opening 30 on opposite sides of the divider 32 to direct the product inflow uniformly over the respective first wash decks 52. Each product inlet deflector 40 includes an inwardly directed member 42 that deflects the product toward the divider 32 to be spread evenly across the longitudinal width of the first wash deck 52. A vertical portion 43 connects the inwardly directed member 42 with an angled portion 45 that serves as an anti-jump device to prevent product particles that impact directly onto the wash deck 52 from bouncing off the deck 52 and heading upwardly toward the dusty air discharge opening 28. The anti-jump extension 45 thus reduces product carryover into the discharge of dusty air from the housing 15.
As can best be seen in
The second air wash deck 55 is supported by the housing 15 in a downwardly directed incline opposite to that of the first air wash deck 52, though also oriented at a minimum angle of 30 degrees to the horizontal. In other words, the second wash decks 55 are angled from both opposing sides to direct a flow of product particles toward the center where the product discharge port 34 is located. Pressurized air is introduced into the second air wash deck 55 from the second inlet openings 24 in the interior panel 14 located beneath the second wash decks 55 to pass upwardly through the second air wash deck 55 similarly to that described above with respect to the first air wash deck 52 to clean any remaining contaminates from the flow of particulate product directed onto the second air wash deck 55.
The product particles moving off of the first wash deck 52 may have sufficient velocity, particularly due to the velocity boost generated by the ribbon of air passing through the slots 58, that the product particles may impact a generally vertical deflector plate 36 defining the outboard sides of the Venturi zones 35. Product deflected off of the deflector plates 36 are directed downwardly to the second air wash decks 55. The product discharge port 34 is provided at the center of the housing 15 between the two second wash decks 55 to receive product from the second wash decks 55 for discharge from the housing 15.
Air entering through the second inlet opening 24 is also directed behind the deflector plates 36, through an air flow chamber 39 that is in flow communication with the clean air plenum 18 beneath the second air wash decks 55, for use in adjusting the air flow in the Venturi zones 35. The air flow chamber 39 extends rearwardly into the clean air plenum 18 rearwardly of the interior panel 14 to deliver air above the second wash decks 55 and behind the deflector plates 36. The adjustment mechanism 38 is connected to each respective deflector plate 36 which is pivotally mounted about the longitudinally extending pivot 37 so that the bottom of each deflector plate 36 is movable into the corresponding Venturi zone 35 to permit a flow of air past the bottom of the deflector plates 36 into the Venturi zones 35 to increase the air flow through the Venturi zones 35. The air flow through the wash decks 52, 55 and through the Venturi zones 35 is directed upwardly toward the dusty air outlet openings 28.
Higher velocity of air moving through the Venturi zones 35 results in a greater counter current flow cleaning action to remove dust particles from the product. The higher the velocity of the air is, the greater the chance of product particles being trapped in the air flow and being carried up to the dusty air discharge opening 28. The vertical distance between the first wash deck 52 and the dusty air discharge opening 28 needs to be as large as possible, which is counter to the design goal of providing a compact deduster apparatus 10. Accordingly, the casing 11 is formed with a pair of extensions 27 located on opposing ends of the casing 11 that project above the rectangular casing 11 into which the dusty air discharge openings 28 are formed. The extensions 27 are in flow communication with the main housing 15 to allow dusty air to flow upwardly through the dusty air discharge openings 28 into the extensions 27 then rearwardly and then downwardly behind the main housing 15 into the dusty air plenum 19 forming the upper portion of the passageways 16 to reach the dusty air discharge port 25 at the back of the casing 11.
By directing the clean air from the inlet port 20 into the clean air plenum 18, air can be introduced under pressure to the first air wash decks 52 through the first inlet opening 22 centrally located within the diamond-shaped wash deck configuration below the first wash decks 52, and to the second wash decks 55 through laterally spaced second air inlet openings 24 positioned beneath the second wash decks 55, as is indicated by air flow arrows 61-63 in
The dusty air discharge path, represented by air flow arrows 64 in
In operation, the dedusting apparatus 10 receives a volume of contaminated particulate material to be cleaned which is introduced into the product inlet port 30. The particulate material passes through the magnetic flux field generated by magnetic coil 31 to disrupt the static charge attraction causing the contaminates to adhere to the individual particles of the particulate material. Material flow control is important in order to cause particulate particles to disperse in such a way that air can flow freely through the product stream so as to lift contaminants upward away from the product. The flow of material through the dedusting apparatus 10 is controlled by the inlet deflector members 40 and divided into laterally opposing flow paths by the divider 32 to drop onto the first air wash decks 52. Preferably, the product inlet deflectors 40 and the divider 32 are positionally adjustable to optimize the flow characteristics of the particulate material being fed into the apparatus 10.
If the layer of particulate material on the first air wash deck 52 is too thick, air may prevented from passing efficiently through the particulate material to separate out the contaminates. If the layer of particulate material is too thin, the air flow will not be efficiently utilized. The divider 32 must be also positioned properly to divide the product flows to the opposing first air wash decks 52. If one side of the wash deck apparatus 50 gets overloaded, as compared to the opposite side, the air flow through the wash deck apparatus 50 will seek the path of least resistance and move away from the overloaded side of the wash deck apparatus 50, thus reducing the cleaning operation of the apparatus 10.
Pressurized air flows through the holes in first air wash deck 52 to separate the contaminates from the individual pellets of product material, the contaminate particles being smaller and lighter than the product particulates. The air flow through slots 58 accelerates the partially cleaned product toward deflector plate 36. This partially cleaned particulate product then passes from the first wash decks 52 toward the corresponding second wash decks 55 and passes through a higher velocity counter air flow in the Venturi zones 35 passing upwardly on each opposing side of the wash deck apparatus 50 from the second air wash deck 55 through the narrowed opening between the vertical member 53 of the first air wash desk 52 and the deflector plate 36. The particulate product then falls onto the second air wash decks 55 for a further separation of contaminates from the particulate product. The lower deck members 54 direct the air passing through the second air wash decks 55 and the layer of particulate material thereon into the respective Venturi zones 35 as defined above. Lower dusty air discharge openings are not utilized, and thus special air deflector members are not necessary to prevent product carryover from the second air wash decks 55, to increase the air flow through the respective Venturi zones 35.
The first air wash deck 52 separates small particles of 100 microns and less from the flow of particulate material thereon. The Venturi zones 35 (between the first air wash decks 52 and the deflector plates 36), when adjusted correctly, will remove larger contaminants, thereby providing a two stage separation of contaminants as large as 1/52 of an inch. The particulate material is then passed across the second air wash deck 55 with residual contaminates being separated at this time. Finally, the cleaned product drops to the bottom of the main housing 15 and is discharged out of the dedusting apparatus 10 through the product outlet port 34.
Because of the different characteristics of the various products that can be introduced into the apparatus 10 to be cleaned of dust particles, certain aspects of the apparatus are made adjustable, as is generally known in the art. For example, the positions of the product inlet deflectors 40 and the divider 32 are preferably positionally adjustable to evenly and equally distribute product flows to the opposing air wash decks 52, 55. The deflector plates 36 forming the outboard sides of the respective Venturi zones 35 are preferably positionally adjustable so as to both change the physical dimensions of the Venturi zones 35, which alone changes the velocity of the air flowing through the Venturi zones 35, but also adds air flow past the deflector plates 36 into the Venturi zones 35. Too much air and too great of a velocity for some products will increase the product carryover into the dusty air discharge openings. Under typical operating circumstances, the preferable pressure differential between the Venturi zones 35 and the dusty air discharge openings 28 is equal to about five inches of water.
A clean air adjustment valve 21 is provided at the top of the clean air plenum 18 to control the volume and pressure of the clean air flow being introduced into the apparatus 10 through the clean air inlet port 20. Similarly, air bleed out disks 24a are provided in the clean air plenum 18 below the second air wash decks 55 to control the air flow through the second wash decks 55 and the air flow available to the Venturi zones 35 from behind the deflector plates 36.
It will be understood that changes in the details, materials, steps and arrangements of parts, which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles of the scope of the invention. The foregoing description illustrates the preferred embodiment of the invention; however, concepts, as based upon the description may be employed in other embodiments without departing from the scope of the invention. Accordingly, the following claims are intended to protect the invention broadly, as well as in the specific form shown.
