Abstract:
A powder receiving device has a loading chamber with an integral dust collector. The dust collector preferably includes at least one bag filter which filters air taken from above powder loaded into the loading chamber. The filtered air is then fed either back into the loading chamber, into a hopper where the powder is released to an external location, or out over the container from which the powder is loaded. This air flow provides for increased fluidity of the powder. The bag filter is positioned facing the loading chamber, such that when a backwash mean sends a pulse of air into the bag filter, the collected powder is dropped back into the loading chamber. The resulting powder receiving device prevents powder from escaping when powder is transferred from a container into the loading chamber. Since the powder is prevented from escaping, the powder receiving device further provides a clean workplace.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a powder receiving device for receiving various types of powder transported from a truck or the like. More specifically, the present invention relates to a powder receiving device for receiving granular and/or powdered food products, feed, chemical products, and pharmaceutical products. 
     Powder is conventionally stored and shipped in bags or plastic containers. Alternatively, powder may be bulk shipped using a transport device such as a dump truck or a dump semi-trailer having a container with an upper section that can be opened and closed. Powder shipped in this manner arrives at a destination plant where the powder is transported with a powder air transport system installed in the plant. The powder is received by a powder receiving device (receiver) and is then stored in a silo. 
     Referring to FIGS. 1 and 2, a conventional system is shown for air transporting a powder from a dump truck  100  into a silo  108 . Dump truck  100 , arriving at a plant  101 , backs into a loading area  102 . A receiving hood  103 , installed in loading area  102 , has a powder loading opening  103   a  formed on a side surface. Dump truck  100  backs toward powder loading opening  103   a . A container  100   a  is lifted and powder is loaded into receiving hood  103  from a rear door  100   b . The bottom of receiving hood  103  forms a hopper-style powder outlet opening  103   b . A chain conveyor  104  connects at a lower region of powder outlet opening  103   b  to provide lateral transfer of powder. 
     Powder loaded into powder loading opening  103   a  drops from powder outlet opening  103   b  through a powder feeding opening  104   a  of chain conveyer  104 . Powder laterally transferred by chain conveyor  104  is released through a powder transfer opening  104 b. 
     A loading hopper  105   a , attached at a lower region of powder transfer opening  104   b , transfers the powder vertically into a bulk conveyor  105 . Powder dropped through powder transfer opening  104   b  is transferred upward by bulk conveyor  105 . When powder reaches an uppermost section  105   b  of bulk conveyor  105 , powder drops through a powder supplying duct  105   c.    
     Powder supplying duct  105   c  connects to a powder supply opening  106   a . 
     The powder, laterally transferred by a chain conveyor  106 , drops into a powder transfer opening  106   b . A connecting pipe  107  connects powder transfer opening  106   b  to a ceiling  108   a  of silo  108 . Powder stored inside silo  108  is fed through an outlet gate  109  at the bottom of a hopper  108   b  into a supply pipeline (not shown in the figure). 
     In the conventional powder supply system described above, a considerable amount of powder escapes when the powder is loaded in bulk into receiver hood  103 . Powder blown out from powder loading opening  103   a  enters back into container  100   a  of dump truck  100 , making dump truck  100  dirty. In addition, the escaping powder aggravates the work environment around loading area  102 , requiring frequent cleaning of loading area  102 . 
     A dust collector  110  is attached at an upper floor of plant  101 . A suction pipe  111  connects the inside of receiver hood  103  with dust collector  110 . Powder returns to silo  108  from an outlet side of dust collector  110  through a circulation pipe  112 . A suction fan  113 , disposed on an upper surface of dust collector  110 , takes air in through dust collector  110  and lets the air out through an outlet pipe  114  attached to a vent opening  115  of plant  101 . This conventional system restricts the escape of powder to some degree. 
     However, since dust collector  110  is installed at a high position, extra space is required. Also, since outside air enters receiver hood  103 , the internal suction power (pressure distribution) is uneven, resulting in stagnation of air and preventing efficient dust collection. Furthermore, powder retrieved in dust collector  110  must be returned to a supply line of silo  108 , allowing residual powder inside circulation pipe  112  to decompose. If dust collector  110  is used, different powders from other sources can become mixed with the desired powder, thus decreasing product value. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is a first object of the present invention to provide a powder receiving device which results in a clean workplace where the escape and flying up of powder in a loading section is minimized. 
     It is a second object of the present invention is to provide a powder receiving device which prevents unevenness of pressure during dust collection, thus allowing dust to be efficiently collected. 
     It is a third object of the present invention is to provide a powder receiving device which prevents pressure loss in the duct piping and prevents contamination inside the duct piping. 
     It is a fourth object of the present invention is to provide a powder receiving device which uses an air blower that requires low suction power in the dust collector. 
     It is a fifth object of the present invention to provide a powder receiving device which substantially prevents noise from the dust collector. 
     Briefly stated, the present invention provides a powder receiving device having a loading chamber with an integral dust collector. The dust collector preferably includes at least one bag filter which filters air taken from above powder loaded into the loading chamber. The filtered air is then fed either back into the loading chamber, into a hopper where the powder is released to an external location, or out over the container from which the powder is loaded. This air flow provides for increased fluidity of the powder. The bag filter is positioned facing the loading chamber, such that when a backwash mean sends a pulse of air into the bag filter, the collected powder is dropped back into the loading chamber. The resulting powder receiving device prevents powder from escaping when powder is transferred from a container into the loading chamber. Since the powder is prevented from escaping, the powder receiving device further provides a clean workplace. 
     According to an embodiment of the present invention, there is provided a powder receiving device for receiving powder comprising a housing, a loading chamber within the housing for receiving the powder, a powder loading hopper attached at a bottom of the housing to direct powder from the loading chamber to an external location, a blower, the blower moving air on an air path originating inside the loading chamber, at least one bag filter in the housing in the air path, the bag filter being effective for filtering particles of the powder in the air path, and the at least one bag filter being positioned to permit the particles to fall into the powder loading hopper upon release from the bag filter. 
     According to another embodiment of the present invention, there is provided an integrated powder receiving device comprising a housing, a powder loading chamber in the housing, a powder loading hopper attached at a bottom of the powder loading chamber to receive powder from the housing and to direct powder to an external location, a fan drawing air from the powder loading hopper into an air path, at least one bag filter in the air path, the bag filter being of a type effective for filtering airborne particles of the powder from the air path, and the air path directed to at least one high location and one low location in the housing. 
     According to a further embodiment of the present invention, there is provided a powder receiving device comprising a loading chamber for conveying powder to a hopper therebelow, a blower drawing air on an air path from the loading chamber, a first air outlet from the air path, the first air outlet being close to the hopper, thereby increasing a fluidity of the powder in the hopper, whereby a flow of the powder through the hopper is improved, and a second air outlet high in the loading chamber for producing a downward flow of air toward the hopper, whereby the powder is preferentially directed toward the hopper. 
     The invention provides a powder receiving device wherein the dust collector is a bag filter. By using a bag filter, contamination due to adhesion of powder in internal flanges is eliminated. Thus, internally bent members can be used and flanges may project inward or outward. The result is a powder receiving device having a sleek exterior appearance which is easy to clean. 
     The invention also provides a powder receiving device wherein a filter is oriented toward a powder loading opening. The filter includes a plurality of bag filters disposed laterally in a row. In particular, this orientation prevents variations in suction power. 
     The invention also provides a powder receiving device wherein a flap is disposed at an air blowing opening of the bag filter. The flap directs air from the air blowing opening above and below a loading chamber into which powder is loaded. This air direction promotes fluidity of the powder in the loading chamber. In addition, cleaning of the device after powder is received is made easier. 
     The invention also provides a powder receiving device wherein an upper air blowing opening blows air flowing above the flap to below the loading chamber. The upper air blowing opening keeps the dust source (the container of the truck) near the powder loading opening clean. 
     The invention further provides a powder receiving device wherein a lower air blowing opening blows air flowing below the flap to above the loading chamber. This promotes fluidity of the powder. 
     The invention also provides a powder receiving device further including overlapping opening/closing gates. These gates protect the powder receiving operation from air currents. 
     The invention further provides a powder receiving device wherein a dust protection sheet is disposed on the opening/closing gate. The dust protection sheet provides further improvements in sealing the powder receiving operation from air currents. 
     The invention also provides a powder receiving device wherein the opening/closing gates operate by an eccentric sprocket mechanism. This mechanism allows the dust protection sheet to be smoothly folded when the opening/closing gates are closed. 
     The invention further provides a powder receiving device further including a sensor which detects the approach of transporting means. A control device controls the opening and closing of a door in response to a signal from the sensor. The sensor/control device combination automates the powder receiving operation. 
    
    
     The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross section of a powder receiving device according to a conventional technology. 
     FIG. 2 is an enlarged cross section drawing of a portion of the powder receiving device of FIG.  1 . 
     FIG. 3 is a cross sectional right side view of the internal structure of a powder receiving device according to an embodiment of the present invention. 
     FIG. 4 is a partially cut-away perspective drawing showing the internal structure of the powder receiving device of FIG.  3 . 
     FIG. 5 is a cross sectional rear-view drawing of the powder receiving device of FIG.  3 . 
     FIG. 6 is a front-view drawing of the powder receiving device of FIG.  3 . 
     FIG. 7 is a plan drawing of the powder receiving device of FIG.  3 . 
     FIG. 8 is a block diagram of the control unit system from the powder receiving device of FIG.  3 . 
     FIG. 9 is a flowchart showing the operations performed by the control unit of FIG. 8 during automated bulk shipping of powder. 
     FIG. 10 is a partial cross sectional drawing of a truck approaching a powder receiving device. 
     FIG. 11 is a partial cross sectional drawing of the rear of the truck entering a powder loading opening of a powder receiving device. 
     FIG. 12 is a partial cross sectional drawing of the powder being loaded from the truck to a powder receiving device. 
     FIG. 13 is a partial cross sectional drawing of the truck moving away from a powder receiving device. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIGS. 3 and 4, a powder receiving device  1  includes a receiver hood  1   a , in which plates, preferably aluminum plates, form a box. A front surface and a lower surface of receiver hood  1   a  are open. A powder loading opening  2 , at a front surface of powder receiving device  1 , allows insertion of a rear section of a container  17   a  of a dump semi-trailer  17  (see FIG.  12 ). 
     Referring to FIGS. 6 and 7, an automatic opening/closing gate  3 , pivotably attached to left and right ends of powder loading opening  2 , has doors which open and close powder loading opening  2 . Automatic opening/closing gate  3 , sealing powder loading opening  2  from the left and right, is connected to an actuator  3   b  by a rotating shaft  3   a . Actuator  3   b  opens and closes automatic opening/closing gate  3  using rotating shaft  3   a  as indicated by the dotted lines in FIG. 7. A dust-protection vinyl sheet  3   c  is attached to an inner side at the end of each door of automatic opening/closing gate  3 . Dust-protection vinyl sheet  3   c  operates integrally with each door of automatic opening/closing gate  3 . When automatic opening/closing gate  3  is closed, ends of dust-protection vinyl sheets  3  fold to partially overlap. Automatic opening/closing gate  3  includes an eccentric sprocket mechanism (not shown) to stagger the timing by which the left and right doors open and close, allowing dust- protection vinyl sheet  3   c  to smoothly fold. A plate-shaped sealing member  4  is rotatably attached to an upper end surface of the open end of powder loading opening  2  with a shaft  4   a . Sealing member  4  is preferably pulled vertically (hanging down) by a spring or the like. A plateshaped sealing member  5  is pivotably attached to a lower end surface of the open end of powder loading opening  2 . Sealing member  5  is pulled by a spring or the like to maintain an upright position. A gap is formed between a lower end of sealing member  4  and an upper end of sealing member  5 . Thus, when powder is not being received, outside air is shielded from the inner space of powder receiving device  1 . When powder is being received, the inner space of powder receiving device  1  is continuous with the outside air. 
     Referring to FIGS. 3 through 5, four bag filters  30  are laterally positioned inside powder receiving device  1 . Multiple long filters  6  are horizontally attached to a cell plate  7  of bag filters  30 . A retainer (not shown) having an elliptical lateral cross-section shape is covered with a long, thin, envelope-shaped filter cloth to form long filter  6 . During dust collection, the filter cloth contracts and attracts powder. During pulsed backwash phases, the filter cloth expands to a roughly elliptical shape, filling a gap formed between adjacent filter cloths. The impact between adjacent filter clothes during backwash phases causes powder to be brushed off. 
     The bases of long filters  6  are attached to multiple holes in vertically positioned cell plate  7 . The result is a grid in which cell plates  7  and long filters  6  are perpendicular to each other. Cell plates  7  partition an inner space of powder receiving device  1  into a loading chamber  40 , where powder is loaded, and a suction chamber  50 . Multiple suction motor fans  8 , positioned above long filters  6 , are used for dust collection. Suction motor fans  8  include air suction openings  8   a  and air vent openings  8   b . Air suction openings  8   a  open into suction chamber  50 . Air vent openings  8   b  open into vent chamber  60 . Bag filters  30  include multiple backwash air jet nozzle pipes  14  laterally extended across the inside of suction chamber  50 . Electromagnetic valves  14   a  feed high-pressure air pulses to air-jet nozzle pipes  14 . Air filtered through long filters  6  is taken into air suction opening  8   a  from suction chamber  50 . The air is then let out into vent chamber  60  through air vent opening  8   b , where the air is branched out in two directions by a flap  9 . Japanese patent number 2634042, entitled “Bag Filter Device”, herein incorporated in its entirety by reference, describes a bag filter usable as bag filter  30  of the present invention. 
     Flap  9  is in front of air vent opening  8   b  which opens into vent chamber  60 . Air led into air vent chamber  60  from air vent opening  8 b branches out into either loading chamber  40  (to the left in FIG. 4) or an air box  12  (down in FIG.  4 ). The amount of air led into loading chamber  40  and air box  12  is controlled by adjusting flap  9 . A horizontal air duct  10  horizontally guides air branched upward by flap  9 . A portion of the upwardly branched air is let out into an upper section of loading chamber  40 . A cleaning air blowing opening  10   a , at the end of horizontal air duct  10 , opens into loading chamber  40  through an elongated curtain extending above the length of powder loader opening  2 . An air curtain blowing opening  10   b  is a laterally elongated duct disposed on an upper surface of the front side of powder receiving device  1 . A portion of the air flowing through horizontal air duct  10  is blown into loading chamber  40 , while most of the air is blown out from powder receiving device  1  through air curtain blowing opening  10   b.    
     A vertical air duct  11  guides air branched downward by flap  9  inside receiver hood  1   a . The air is blown downward from an outlet opening  11   a  of vertical air duct  11 , scattered laterally inward at a long air box  12 . Long air box  12  is laterally positioned at a lower section of powder receiving device  1 . An air nozzle  12   a  releases the air scattered in air box  12  into a powder loading hopper disposed at an opening at a lower surface of powder receiving device  1 . The air blown from air nozzle  12   a  and the air blown from air curtain blowing opening  10   b  accelerate the fluidity of powder inside loading chamber  40  when powder is loaded. The blown air also provides cleaning for the inside of loading chamber  40  and powder loading hopper  16  after powder loading is complete. 
     An inspection door  13  is installed at the back of powder receiving device  1 . Inspection door  13  is opened to replace filters  6  and to inspect the inside of powder receiving device  1 . Inspection door  13  is opened and closed as indicated by the dotted lines in FIG.  7 . 
     An access door  20 , positioned below inspection door  13 , contains a control unit  15 . Powder loading hopper  16  (see the dotted lines in FIG.  3  and FIG. 5) is connected to an opening on a bottom surface of powder receiving device  1 . As described above, high-pressure air blown out from air nozzle  12   a  is blown inside powder loading hopper  16 . 
     Referring to FIG. 8, control unit  15  contains a microcomputer. The microcomputer includes a CPU  15   a , RAM  15   b , ROM  15   c , an I/O port  15   d , and a bus line  15   e , connecting each of these elements. I/O port  15   d  connects to a control panel  15   f , actuator  3   b , suction motor fan  8 , an actuator  9   a , a truck sensor  18 , and an electromagnetic valve  14   a . Control unit  15  controls powder loading operations. 
     Referring to FIGS. 10 through 13, the following is a description of how powder receiving device  1 , according to a preferred embodiment of the present invention, is installed in a loading section of powder/feed plant  101  for receiving bulk shipments of powder. 
     First, truck sensor  18  is installed on the ground of a truck receiving area  80  into which a dump semi-trailer is driven. Next, electrical connections are made between a power supply and control unit  15  as well as between truck sensor  18  and control unit  15 . Pipes for high-pressure air are then laid out. To compare the powder receiving device of the present to a conventional powder receiving device as shown in FIGS. 1 and 2, in plant  101 , powder receiving device  1  is installed in place of conventional receiver hood  103 , dust collector  110 , suction pipe  111 , circulation pipe  112 , fan  113 , and exhaust opening  115 . 
     The housing and the like for powder receiving device  1  can be formed from any suitable material, preferably a light metal, more preferably, aluminum plates. The use of aluminum plates makes the device lighter, allowing installation in large-scale plants without the need for reinforcements. The device is assembled with internally bent materials using bolts and nuts. Welding is avoided as much as possible. Thus, the cosmetic appearance is improved by having a housing substantially free from external projecting elements. Also, transportation of the device is relatively easy, since the device is assembled as a single unit at a production plant before transporting to a powder/feed plant or the like. Installation in the plant simply involves connecting the wiring, high-pressure air pipes, and the like. The ease of installation significantly reduces installation time. 
     Powder receiving device  1 , installed in a receiving section of powder/feed plant  101  in the manner described above, is placed in a standby state by turning on power to control panel  15   f  (see FIG.  8 ). Powder receiving operation is performed based on a program stored beforehand in control unit  15 . 
     Referring to FIGS. 8 through 10, when power to control panel  15   f  is turned on, CPU  15   a  begins powder receiving operation and control goes to step  100 . CPU  15   a  repeatedly checks truck sensor  18  (see FIGS.  10  through  13 ). CPU  15   a  waits for truck sensor  18  to be turned ON. When dump semi-trailer  17  enters the receiving section and passes truck sensor  18 , truck sensor  18  detects the entry of dump semi-trailer  17 , sending a signal to control unit  15 . As a result, step  100  determines that truck sensor  18  has been turned ON. If a NO is returned, the operation is repeated. 
     When control proceeds to step  110 , CPU  15   a  sends an open signal to actuator  3   b , opening automatic opening/closing gate  3 . Automatic opening/closing gate  3  protects the powder loading process from horizontal air currents. At step  120 , a drive signal is sent to suction motor fan  8 , creating a negative pressure inside filter  6 . At step  130 , CPU  15   a  sends a drive signal to electromagnetic valve  14   a  to perform backwashing of bag filter  30 . 
     Referring to FIG. 11, dump semi-trailer  17  moves container  17   a  back stopping at a truck stopper  19 . Container  17   a  enters powder loading opening  2 . Seal member  4  is pushed by container  17   a , pivoting rearward. Seal member  5  is pushed by container  17   a , pivoting frontward. Side surfaces of container  17   a  are covered by dust-protection vinyl sheets  3   c  attached to the end of automatic opening/closing gate  3 . Thus, the inside of powder receiving device  1  is separated from the outside of powder receiving device  1 . 
     Referring to FIGS. 9 and 12, when a rear end of container  17   a  enters completely into powder receiving device  1 , the driver lifts container  17   a . The lifting of container  17   a  causes powder loaded in container  17   a  to be dropped into powder receiving device  1  from a door  17   b  disposed on a section of the rear surface of container  17   a . Powder moves from powder outlet hopper  16  into the next section (silo  108  from FIG.  1  and the like). At step  120 , suction motor fan  8  activates inside powder receiving device  1  to perform dust collection by applying a negative pressure to filter  6 . Powder dropped into powder receiving device  1  is kept from escaping by dust collection performed by filter  6 , as indicated by the arrows in FIG.  12 . 
     Referring to FIGS. 3 and 9, air is blown out from cleaning air blowing opening  10   a  and air curtain blowing opening  10   b  to clean container  17   a  of dump semi-trailer  17 . Air blown from air nozzle  12   a  also increases powder fluidity to help prevent clogging. At step  130 , electromagnetic valve  14   a  activates to perform backwashing by sending air pulses to backwash air jet nozzle pipe  14 . In response to input from control panel  15   f , actuator  9   a  appropriately adjusts the angle of flap  9 . 
     At step  140 , CPU  15   a  waits for truck sensor  18  to be turned OFF. Once powder from container  17   a  is completely unloaded, empty container  17   a  returns to its base. Dump semi-trailer  17  then moves forward, causing sealing members  4  and  5  to be restored by springs to their upright positions. 
     Referring to FIGS. 9 and 13, dump semi-trailer  17  moves away from the position of truck sensor  18 , causing trucking sensor  18  to send an OFF signal. CPU  15   a  reads this sensor signal to determine whether the sensor signal is now OFF. This operation is repeated if the response is NO. 
     At step  150 , CPU  15   a  closes automatic opening/closing gate  3  while sending a stop signal to suction motor fan  8  to halt dust collection. At step  160 , CPU  15   a  sends a stop signal to electromagnetic valve  14   a  to halt backwash operations. As a result, powder receiving device  1  halts dust collection and backwash operations for bag filter  30 . At step  170 , CPU  15   a  sends a close signal to actuator  3   b  to close automatic opening/closing gate  3 . This completes the powder receiving operation. At completion, powder hopper  16  is empty. Dust cleaning and backwash operations are performed as appropriate to clean out residual powder inside powder receiving device  1 . 
     With the structure described above, the embodiment of the present invention provides the advantages described below. 
     (1) During unloading of powder, filter  6  of bag filter  30  is positioned close to the dust source near rear door  17   b  of container  17   a  of dump semi-trailer  17 . This positioning allows a uniform pressure distribution, preventing air from stagnating, providing efficient dust collection. Also, the need for the suction duct of the conventional technology is eliminated. This reduces the pressure loss at the duct and allows the use of an economical, quiet, and low-power suction motor fan  8 . 
     (2) Powder brushed off from filter  6  falls freely to be retrieved in powder loading hopper  16 . This allows for efficient powder reception. 
     (3) During the powder receiving operation, dust protection vinyl sheets  3   c  shield an area behind container  17   a  of dump semi-trailer  17 . This prevents powder from leaking outside. 
     (4) By using an insect screening sheet as dust protection vinyl sheets  3   c , insects are prevented from entering into powder receiving device  17   a  from the outside. 
     (5) When powder receiving device  1  idle, automatic opening/closing gate  3  and sealing members  4  and  5  seal off the opening of receiver hood  1   a . This prevents powder from flying out, keeping the loading section tidy. When automatic opening/closing gate  3  is open, the receiving operation is protected from horizontal air currents. 
     (6) The housing of powder receiving device  1  is preferably formed by assembling aluminum plate panels. This provides a light yet large device without requiring external reinforcements. 
     (7) Since the main elements such as receiver hood  1   a , bag filter  30 , and control unit  15  are integrally formed as a single system, transporting the device is made easier. 
     (8) The installation of the unit in a plant involves a modular method where the unit is installed directly in the plant. This greatly reduces the time required for installation. The modular method also facilitates maintenance and cleaning after operation in the plant. 
     (9) By using an eccentric sprocket mechanism in automatic opening/closing gate  3  to provide offset timings for the opening and closing of left and right gates, the folding up of dust protection vinyl sheet  3   c  attached at the end of each gate is facilitated. 
     (10) Air from suction motor fan  8  is blown out in the form of an air curtain from cleaning air blowing opening  10   a  to container  17   a  of dump semi-trailer  17 . This allows for the cleaning of container  17   a.    
     (11) By having bag filter  30  installed inside powder receiving device  1 , residual powder at internal corners of the housing are eliminated and the device can be assembled as a box using bolts and nuts to connect internally bent flanges. This eliminates projections (externally bent flanges and the like) from an outer surface of the housing, improving the appearance of the device while making cleaning easier. 
     (12) Suction motor fan  8  is covered by receiver hood  1   a  so that noise during operation is minimized. 
     (13) Since the angle of flap  9  is adjustable, flow of air within powder receiving device  1  can be freely controlled. 
     Having described preferred embodiments of the invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.