Patent Grant
7337926
This invention relates generally to freight containers and specifically to an air blown system for loading and unloading of intermodal containers for powder bulk solid materials.
This invention was not made under contract with an agency of the US Government, nor by any agency of the US Government.
In order to reduce the cost, time and manpower of long distance shipping, the intermodal cargo container is commonly used. Such containers are standardized shapes and sizes and usually have standardized handling devices such as standardized grips, hooks, tie downs and so on that allow shippers, handlers, stevedores, longshoreman, truckers and others to handle numerous containers quickly, almost regardless of the actual contents of the containers.
Normally, such containers are built to specifications issued by various authorities: international use of containers built to these specifications is one of the key ingredients of the modern free trade system, for without such standards, fast handling would be almost impossible. Perhaps the foremost authority for issuance of such standards is the ISO or International Standards Organization, which issues numbered standards directives. For example “ISO 1496/IV” is one standard for cargo containers, “ISO 1161” another standard for the corner locks of such containers and so on. The Association of American Railroads has similar standards on the same topic, for example AAR M-930. These standards most importantly relate to dimension, but also relate to weatherability, strength and other issues.
Shipping of bulk powders of all sizes from micron-sized through quarry-sized dry particulate can be a surprisingly aggravating proposition, even when such standardized cargo containers are utilized. Firstly, they are collectively amorphous so entirely closed containers are necessary. Powders and dry particulate matter in general tend to behave in a fashion that allows such bulk powders as food products (e.g. Grain, Flour, Sugar, Dextrose, Starch, Cake Mixes, Cocoa, Coffee, Enzymes, Nutrients, Feeds, Pet Foods, Seeds, Spices, et al.) Chemicals, (e.g. Sodium Chloride, Calcium Chloride, Calcium Carbonate, Lime, Urea, polyethylene, polypropylene, polyester, cements, adhesives, compounds, et al.) Minerals, (e.g. Clays, Fuels, Soils, Stone, et al.). However, such bulk dry particulates or powders usually have an angle of repose, even if a small one, i.e. some angle from the horizontal at which a bulk powder or particulate will rest without flowing, unlike true liquids. Thus, shipping containers for bulk powders tend to have non-flat bottoms. In commonly seen schemes, the container may be subdivided into several smaller compartments, each one with its own “chute” section on the bottom surface of the horizontal container. There are, however, disadvantages to such designs.
For example, a skin or coating of the bulk powder may adhere to the bottom or sides of the container due to frictional forces, necessitating a clean up of some type, probably manual.
Another disadvantage is that the numerous small chutes normally used decreased cargo capacity of the container. Switching to one large chute on the bottom side of the container would merely exacerbate this problem under the dictates of simple geometry.
Flow problems also arise: the typical dry particulate matter has a degree of friction which tends to impede or even block flow, while the typical container is not arranged so as to permit the easy discharge of such bulk particulate matter. These problems and other problems stem from the fact that there is no large vertical drop possible within a normal container. The typical standardized container is a matter of approximately 8 feet to 9.5 feet in height (roughly 2400 to 2900 millimeters). This cannot be increased without defeating the entire purpose for having standardized cargo containers.
Pockets or irregularities in such containers also cause retention of portions of the bulk cargo, forcing manual cleaning of the container to finish the unloading of the cargo, or even worse, posing the risk of contamination of the next cargo.
Various types of bulk cargo containers are known, and have various defects.
Those made of inherently strong materials such as heavy gauge steel plate are excessively heavy in relation to the cargo to be carried, not to mention excessively expensive to manufacture. But containers having internal frames tend to provide numerous catch basins or pockets requiring manual cleaning as described above. Containers having external frames eliminate this problem at the cost of reducing the cargo capacity of the container by the depth of the framework on all sides (because of course the framework must fit within the dimensional standards of the container and therefore the “external” frame is actually inside the edges of the container envelope, thus forcing the container itself to sit within the frame). Containers have been made of fiber reinforced plastic materials (sheets of somewhat flexible material of great strength) with external frames have been tried with limited success: potentially decreased weight but potentially decreased durability.
Various examples may be considered. U.S. Pat. No. 6,401,983 B1 issued Jun. 11, 2002 to McDonald et al for BULK CARGO CONTAINER is an example of one such. It uses a conventional horizontal container and a conventional vertical flow path: bulk materials are loaded from above through doors 138, 140 and 142 and unloaded from beneath through discharge openings such as 116.
U.S. Pat. No. 6,059,372 issued May 9, 2000 to McDonald et al for HOPPER BOTTOM TRAILER shows much the same thinking at work: a conventionally horizontal container, possibly subdivided into compartments or cells and a conventional top-in and bottom-out flow path for the bulk materials handled.
U.S. Pat. No. 5,960,974 issued Oct. 5, 1999 to Kee et al for INTERMODAL BULK CONTAINER teaches a container vessel of aluminum within a rigid outer frame with hoppers extending out the bottom of the device and domed aluminum sealing the ends. Hoppers within the shell are once again to be filled from the top and emptied from the bottom.
U.S. Pat. No. 5,529,222 issued Jun. 25, 1996 to Toth et al for DRY BULK PRESSURE DIFFERENTIAL CONTAINER WITH EXTERNAL FRAME SUPPORT teaches exactly that, once again in a substantially horizontal mode.
U.S. Pat. No. 5,911,337 to Bedecker. teaches a liner to a shipping container; an insert intended merely to replace disposable plastic liners. The device is made of approximately ⅛ inch aluminum (col. 5, lines 22 through 26) or other metal (steel, titanium) or even fiberglass or plastic (col. 6 lines 59 through 64) which may be at most reinforced with a plurality of “tension rings 726” (col. 7 line 65 through col. 8 line 4).
U.S. Pat. No. 6,418,869 to Miller, is a specialized container not having the structures of the present invention, nor is it analogous prior art.
U.S. Pat. No. 3,726,431 to Botkin shows a valve is depicted sized appropriately for liquids having no angle of repose, the opening on the top of the tank is identified not as a hatch for filling the device but as a manhole cover, and a safety rupture disk 79 is shown and described at column 4 lines 65 et seq, indicating that this device is for pressurized liquids.
All of these devices attempt to overcome the friction of the bulk cargo they carry in fairly standard ways. One common solution is to provide relatively highly angled (steep) sided hoppers at the bottom of the vessel, once again however simple geometry dictates that this solution reduces the cargo capacity of the container.
It would be greatly desirable to provide a method of gravity feed of the contents of a bulk cargo container and yet achieve good flow, without overly compromising cargo capacity, and while allowing the additional use of the various devices listed above if desired.
General Summary
The present invention teaches that air may be injected into the sloping bottom of a bulk dry particulate cargo container (micron-sized through quarry-sized dry particulate), causing the bulk dry particulate cargo to enter a bi-phase state having an air matrix with particulate inclusions. One result of this air lubrication is a dramatically reduced coefficient of friction, another may be the lifting or levitating the material off of the container floor. This bi-phase material may be extremely fluid, easily exiting a discharge port without regard to normal bulk dry particulate friction or angle of repose. The present invention also teaches a cargo container having a plurality of air injectors on the sloping bottom of a particulate plenum and having air supply apparatus feeding the air injectors.
Summary in Reference to Claims
It is therefore a first aspect, advantage, objective and embodiment of the present invention to provide a bulk dry particulate cargo container comprising:
It is therefore a second aspect, advantage, objective and embodiment of the present invention to provide a bulk dry particulate cargo container wherein the plenum bottom is not horizontal to grade.
It is therefore another aspect, advantage, objective and embodiment of the present invention to provide a bulk dry particulate cargo container further comprising:
It is therefore another aspect, advantage, objective and embodiment of the present invention to provide a bulk dry particulate cargo container wherein the at least one air/particulate discharge port is located at the bottom of the plenum.
It is therefore another aspect, advantage, objective and embodiment of the present invention to provide a bulk dry particulate cargo container further comprising:
It is therefore another aspect, advantage, objective and embodiment of the present invention to provide a bulk dry particulate cargo container wherein each of the plurality of air injectors further comprises: an air deflector.
It is therefore another aspect, advantage, objective and embodiment of the present invention to provide a bulk dry particulate cargo container wherein the air deflector further comprises one member selected from the group consisting of: a hat, a u-bend, and combinations thereof.
It is therefore another aspect, advantage, objective and embodiment of the present invention to provide a bulk dry particulate cargo container wherein the plurality of air injectors penetrate the plenum bottom.
It is therefore another aspect, advantage, objective and embodiment of the present invention to provide a bulk dry particulate cargo container wherein the pneumatic infeed port is located at the top of the plenum.
It is therefore another aspect, advantage, objective and embodiment of the present invention to provide a bulk dry particulate cargo container further comprising:
It is therefore another aspect, advantage, objective and embodiment of the present invention to provide a bulk dry particulate cargo container
It is therefore yet another aspect, advantage, objective and embodiment of the present invention to provide a method of unloading bulk dry particulate cargo from a container having a top and a bottom and a side, the method comprising:
It is therefore yet another aspect, advantage, objective and embodiment of the present invention to provide a method of unloading bulk dry particulate cargo from a container having a top and a bottom and a side, further comprising:
It is therefore yet another aspect, advantage, objective and embodiment of the present invention to provide a method of unloading bulk dry particulate cargo from a container having a top and a bottom and a side, further comprising:
It is therefore yet another aspect, advantage, objective and embodiment of the present invention to provide a method of unloading bulk dry particulate cargo from a container having a top and a bottom and a side, further comprising:
The overall dimensions of the device conform to various published standards.
First plenum 104 from among the plurality of plenums used in preferred embodiments has a plenum top 112, a plenum bottom 114 and plenum side 116. Plenum bottom 114 is very gently sloped. In contrast to prior art having quite steeply sloped bottoms which form chutes designed to exceed the angle of repose of the intended cargo, this invention allows more efficient use of the container space, as the slope may be quite gentle. In preferred embodiments, the slope may be close to zero, for example, slopes of under 25 degrees may be used, preferably slopes of under 15 degrees. Slopes of zero degrees may in fact be used (in some instances), due to the dramatic reduction in coefficient of friction of the cargo when it is entrained into an air/particulate matrix. The plenum materials may be mild steel, stainless steel, fiberglass, polymers such as Polyethylene, Polypropylene, Polyester, Specialty Resins and composites. In embodiments, there may also be various paints both interior and/or exterior . . . the nature being determined by the application for which the container was intended.
The device may in embodiments be refrigerated, with suitable space limitations imposed by the necessity of providing refrigeration equipment within the standard dimensions.
Hatch 106 is in the best modes contemplated located at the plenum top 112. This hatch may be large enough for human use, for example for cleaning, repairs and maintenance, however, the hatch is intended for gravity feed of bulk dry particulate cargo as discussed in relation to later figures.
Air only exhaust port 108 may also be located at the plenum top 112. This exhaust port is designed to allow air to exhaust there from, particularly during pneumatic feeding of bulk dry particulate cargo into the container's plenum 104. It may be arranged so as to prevent exit of particulate cargo with the air. This may be achieved by means of an air velocity drop chamber which reduces air velocity, causing any suspended matter to drop out, or by means of a serpentine passage, a filter, or merely due to positioning at the top of the plenum.
Air/particulate exhaust port 110 is a key feature of the present invention. This air/particulate exhaust port 110 allows easy exit of an air/particulate cargo mix from the plenum of the container, when the particulate cargo itself, and/or the plenum bottom/floor has been air lubricated so that it has a dramatically reduced coefficient of friction. The particulate is semi-suspended or completely suspended in the air, forming a two phase mixture of an air matrix with particulate inclusions, in the method and structure of the invention.
A mixture of air and particulate has certain very positive qualities. Firstly, the angle of repose is reduced to approximately zero, meaning that the mixture will flow more like a liquid and resist agglomeration and bridging tendencies. Unless considerable support is present, the mixture will be less likely to form piles. The mixture may also easily traverse gentle curves and even pass at speed through relatively small ports, hatches, apertures, pipes, conduits, chutes and tubes. In addition, by adjusting the air flow the particulate cargo may be made to move more rapidly, thus reducing the speed of cargo handling, or in the alternative, allowing handling to occur by means of upstream and/or downstream handling equipment having smaller bores.
The terms “at the plenum top” and “at the plenum bottom” as used herein do not restrictively mean that the port or hatch in question may only penetrate the structural top or bottom itself. Areas of the plenum sides coterminuous to the top or bottom may be included in the term as well. Thus it will be seen that the exhaust port 110 may is in fact be located at the plenum bottom, despite penetrating the plenum side or as an alternative to side-penetration entirely.
While in the embodiment pictured the feed port is depicted to be located at hatch 306, in other embodiments of the invention claimed, it may be located else where in the a plenum top, plenum side and conceivably even a plenum bottom, since the air/particulate mixture has nearly fluid qualities as discussed in reference to
Importantly, the pneumatic feed 322 may feed air into the plenum at the time of discharge of the cargo. However, this is not the only location providing pressurized air for discharge, as will be discussed below in reference to
Pneumatic ports 520 may be used to provide air only for discharge or air/particulate mixtures, as discussed in reference to
One extremely interesting aspect of the present invention is that “downstream” equipment at any stage may in fact be located at a higher elevation than the source of the air/particulate mixture. For example, using the device of the invention, the source of the infeed may be considerably lower than the cargo container, and at discharge, the receiving location may be located at a higher elevation than the cargo container. Normally this would require expensive lifting equipment in addition to the normal lading equipment. However by means of the present invention, the same equipment used to load/unload may also easily lift the particulate. This reduction of secondary and tertiary equipment is one aspect of the present invention which provides a considerable commercial advantage.
Note that first plenum 632 may have more than one hatch: hatch 606 is triplicated in this embodiment, but numbers of hatches from one to five or more, up to a fairly substantial number, may be used.
Note that in embodiments, the plenum bottoms of any embodiment having two or more plenums may be reverse sloped, that is, one may slope one direction while another slopes another direction. This may be used to assist in maintaining alter the center of gravity of the container when full.
Injector air feed line 958 depicted schematically provides air flow into the injector, and may be a pipe, conduit, tube, hose, etc.
Note that the air injector and deflector may take many forms. In the embodiments shown, a U-bend or hat are used, however, the invention is not so limited: tubes with multiple air holes or other deflectors may be used.
Air injector 1150 is fed from air infeed flotation supply 1160 via air feed main 1166 to air injector feed 1168. Cross feed 1170 may help to ensure pressurized air supply to air injectors located further from the air feed main 1166.
Note that the air injection shown in this diagram acts, in the presently preferred embodiment and best mode now contemplated, as an almost “secondary” source of “lubrication” air pressure. At the plenum top or other location, a “primary” source of “transport” air is used to provide a greater air mass through ports such as shown in earlier diagrams: 320, 520, 408, etc. The plenum bottom air injection is intended to keep to cargo from becoming static on the shallowly-sloped plenum bottom, thereby ensuring dynamic flow towards the discharge port. A third source of air (“sidewall” air) is also available, as shown in
Air infeed supply 1260 feeds air feed main 1272, which in turn feeds pressurized air to perforated air drop 1274. The air drop 1274 has perforated sides to discharge air against the sidewalls and disrupt any bridged material that may be hanging against the sidewalls of the plenum. These perforations may be present all along the length of air drop 1274, or in selected portions, may be of uniform or differing sizes and shapes, etc. Discharge end of air drop 1276 is thus positioned close to the junction of plenum bottom and side, where it may consistently entrain or disrupt particulate piled up at that location, forcing it to flow as part of a bi-phase matrix with a newly synthesized and substantially reduced angle of repose.
Note that the air injection shown in this diagram acts, in the presently preferred embodiment and best mode now contemplated, as an almost “secondary” source of air pressure. At the plenum top or other location, a “primary” source of air is used to provide a greater air mass through ports such as shown in earlier diagrams: 320, 520, 408, etc.
Method embodiments of the present invention may comprise some or all of the following steps for unloading of bulk dry particulate cargo from a container having a top and a bottom and a side:
Air injection may occur in one or more locations and methods. Firstly, a portion of air injection occurs through a port such as 320 or 408 which is located near the top of the container and is capable of allowing a large air mass entry. Without wishing to be bound by any particular theory, the air introduced through feed 1160 may be considered to lift, break up, levitate or greatly lubricate the material near the bottom of the plenum in addition to serving as transport air. Finally, the air through the sidewall drop tubes may break free cargo from the sides of the plenum if it is piled at that location, and may transport cargo as well.
The disclosure is provided to allow practice of the invention by those skilled in the art without undue experimentation, including the best mode presently contemplated and the presently preferred embodiment. Nothing in this disclosure is to be taken to limit the scope of the invention, which is susceptible to numerous alterations, equivalents and substitutions without departing from the scope and spirit of the invention. The scope of the invention is to be understood from the appended claims.
This application is a continuation in part of previously filed U.S. application Ser. No. 10/274,185, filed Oct. 18, 2002, now U.S. Pat. No. 7,104,425, in the name of the same inventor, Curtis W. LeRoy, and entitled “Intermodal Bulk Cargo Container and Method” and claims the priority and benefit of that application, the entire specification of which is incorporated herein by this reference.
| Number | Name | Date | Kind |
|---|---|---|---|
| 3726431 | Botkin | Apr 1973 | A |
| 4819830 | Schultz | Apr 1989 | A |
| 4823989 | Nilsson | Apr 1989 | A |
| 5248227 | Hidock et al. | Sep 1993 | A |
| 5529222 | Toth et al. | Jun 1996 | A |
| 5911337 | Bedeker | Jun 1999 | A |
| 5960974 | Kee et al. | Oct 1999 | A |
| 6059372 | McDonald et al. | May 2000 | A |
| 6085664 | Early | Jul 2000 | A |
| 6401983 | McDonald et al. | Jun 2002 | B1 |
| 6418869 | Miller | Jul 2002 | B1 |
| 7104425 | Le Roy | Sep 2006 | B2 |
| Number | Date | Country | |
|---|---|---|---|
| 20050121459 A1 | Jun 2005 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10274185 | Oct 2002 | US |
| Child | 10999237 | US |
