Processes and systems for transferring particulate substances from containers

Preferred processes are provided for unloading a particulate substance from a container using a cover system comprising a cover and a wand extending through the cover. The processes can include installing the cover system on the container so that the cover mates with the container and the wand extends into the particulate substance, connecting a pipe or a hose to the wand, and drawing the particulate substance through the wand and the pipe or hose.

FIELD OF THE INVENTION

The present invention relates to the handling of particulate substances such as catalysts and additives used in fluid catalytic cracking (FCC) operations. More specifically, the invention relates to systems and processes that facilitate the transfer of particulate substances from containers while the containers are covered.

BACKGROUND OF THE INVENTION

FCC units used to conduct FCC operations commonly include a circulating inventory of bulk catalyst. The bulk catalyst is typically used to perform a primary function, such as producing naptha from petroleum feedstock, the naptha being further processed into gasoline. Additives, which are often in the same fluidizable and particulated form as the catalyst, are often introduced into the circulating inventory of bulk catalyst to perform a secondary function such as reducing certain types of emissions, e.g., SOx or NOx, produced by the FCC unit. These emissions are produced in the catalyst regenerator of the FCC unit where coke deposits from the cracked petroleum are burned off and the regenerated catalyst returned to the circulating catalyst inventory. These additives are usually introduced into the regenerator using an injection device commonly referred to as a “loader.” Loaders are also used to add catalyst to the bulk inventory as additional catalyst becomes necessary due to factors such as attrition and deactivation.

Particulate substances, such as catalysts and additives used in FCC units, are usually shipped from the manufacturer to the point of use, e.g., a refinery, in containers. For example, catalysts and additives are commonly transported in standard 55-gallon drums capable of holding approximately 300 pounds of the catalyst or additive. Tote bins capable of holding approximately 2,000 pounds of catalyst or additive are another type of commonly-used shipping container.

The containers used to ship catalyst or additive are usually covered during shipping to prevent contamination of the catalyst or additive by oxygen or moisture from the ambient environment. Covering the containers is also necessary to prevent fugitive emissions and other losses of the catalyst or additive, and to reduce the potential for human contact with the potentially toxic or caustic catalyst or additive.

The catalyst or additive can be unloaded from the shipping container to a silo or other suitable storage vessel at the refinery. The unloading process is typically conducted by removing the cover of the container, and vacuuming the catalyst or additive. Removing the cover is necessary to prevent a substantial pressure differential from developing between the interior of the container and the ambient environment. A substantial pressure differential can potentially collapse or otherwise damage the container.

Vacuuming the catalyst or additive while the cover of the container is removed, however, exposes the catalyst or additive to the environment. Such exposure can be disadvantageous in applications where the contents of the container are subject to contamination when exposed to the ambient environment. For example, many catalysts and additives degrade when exposed to moisture. Exposure to moisture can be particularly disadvantageous when the catalyst or additive possesses hygroscopic, i.e., moisture absorbing, properties.

Moreover, particulate substances that possess pyrophoric, i.e., spark or flame inducing, properties can present a fire or explosion hazard when exposed to or released into the ambient environment. Also, some types of catalysts and additives can degrade when exposed to the oxygen normally present in the ambient environment.

Consequently, an ongoing need exists for systems and methods that can facilitate the unloading of particulate substances from containers while minimizing or substantially eliminating exposure of the particulate substances to the ambient environment.

SUMMARY OF THE INVENTION

Preferred processes and cover systems are provided that permit particulate substances to be unloaded from containers while the containers are covered.

Preferred processes are provided for unloading a particulate substance from a container using a cover system comprising a cover, a fitting attached to the cover, and a wand mounted on and in fluid communication with the fitting. The processes comprise installing the cover system on the container so that the cover mates with the container and the wand extends into the particulate substance, connecting a pipe or a hose to the fitting, and drawing the particulate substance through the wand, the fitting, and the pipe or hose.

Preferred processes for transferring catalyst and/or additive from a container to an injection device that injects the catalyst and/or additive into a fluid catalytic cracking unit comprise installing a cover on the container; inserting a wand into the catalyst and/or additive; placing the wand in fluid communication with a vacuum source of the injection device; and drawing the catalyst and/or additive from the container by way of the wand.

Preferred processes for transferring a particulate substance from a container to an injection device capable of injecting the particulate substance into a fluid stream comprise installing a cover on the container, and vacuuming the particulate substance through the cover and into the injection device.

Preferred cover systems for a container comprise a cover that mates with the container, a wand capable of being inserted through a hole formed in the cover, and a cradle for holding the container in a tilted orientation.

Preferred systems for introducing catalyst and/or additive into a fluid catalytic cracking unit comprise an injection device comprising a vacuum source and a chamber. The chamber is in fluid communication with the vacuum source, receives the catalyst and/or additive, and is capable of being pressurized to inject the catalyst and/or additive into the fluid catalytic cracking unit.

The systems also comprise a container defining a volume that holds the catalyst and/or additive, and a cover system. The cover system comprises a cover capable of mating with the container and further defining the volume, and a wand capable of extending through the cover and into the volume so that the wand is inserted in the catalyst and/or additive. The wand is in fluid communication with the vacuum source so that the catalyst and/or additive is drawn through the cover and into the injection device in response to a vacuum generated by the vacuum source.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

FIGS. 1-8Bdepict a preferred cover system10for a container such as a drum12. The cover system10can facilitate the transfer of a particulate substance from the drum12. The drum12can be, for example, a standard 55-gallon drum. The particulate substance can be, for example, catalyst and/or additive11for use in an FCC unit (not shown). The catalyst and/or additive is depicted inFIG. 1by the reference character11.

The use of the cover system10in connection with the drum12is disclosed for exemplary purpose only. Alternative embodiments of the cover system10can be used with other types of containers, including tote bins, square or rectangular containers, and other types of containers having shapes and sizes different than those of a 55-gallon drum. Moreover, the cover system10can be used to facilitate the transfer of particulate substances other than catalysts and additives.

The cover system10comprises a cover14configured to mate with the drum12. The cover14and the interior of the drum12define an internal volume25, as shown inFIG. 1. The cover system10allows the internal volume25to be placed in fluid communication with a vacuum source, such as an injection device in the form of a loader102depicted inFIG. 9. The vacuum generated by the loader102can draw the catalyst and/or additive11from the drum12and into the loader102. The loader102can then inject the catalyst and/or additive11into a regenerator of the FCC unit.

The loader102comprises a dust collector116and a transfer pot118. The transfer pot118adjoins the dust collector116, and is in fluid communication with the regenerator of the FCC unit on a selective basis. The loader102also comprises a vacuum producer130in fluid communication with the dust collector116.

The dust collector116defines an internal volume126. The dust collector116includes three pipe guides140that extend from a wall of the dust collector116and into the internal volume126.

The internal volume126can be placed in fluid communication with three of the drums12by hoses138or other suitable means such as hard piping. Each hose138can be connected to the dust collector116by way of an associated valve142mounted on the dust collector116. The inner diameter of each hose138is preferably approximately one to approximately five inches. More preferably, the inner diameter of each hose138is approximately two to approximately three inches. Preferred values for the inner diameter of the hoses138are presented for exemplary purpose only; the diameter of the hoses138can lie outside of the noted ranges.

Each pipe guide140is connected to an associated one of the valves142. The valves142permit the associated hoses138and drums12to be isolated from the internal volume126on a selective basis. An internal or external manifold (not shown) can be used in lieu of the three separate valves142in alternative embodiments of the loader102. Moreover, alternative embodiments of the loader102can be equipped with more or less than three valves142and three pipe guides140.

The vacuum producer130generates a vacuum within the internal volume126of the dust collector116. The vacuum draws the catalyst and/or additive11from one of the drums12when the associated valve142is open to permit the internal volume126to communicate with the drum12.

The catalyst and/or additive11is discharged into the internal volume126of the dust collector116by the corresponding pipe guide140after passing through the associated hose138and valve142. The path of the catalyst and/or additive11is denoted inFIG. 9by arrows143. The catalyst and/or additive11falls to the bottom of the dust collector116and into the transfer pot118. The transfer pot118is subsequently pressurized, and the catalyst and/or additive11is injected into the regenerator of the FCC unit in response to the pressure within the transfer pot118.

The operation of the loader10, including opening and closing of the valves142, pressurization of the transfer pot118, generation of the vacuum in the dust collector116, etc., can be controlled automatically by an electronic controller (not shown) of the loader102.

Further details of a loader suitable for use as the loader102are included in U.S. application Ser. No. 10/806,563, filed Mar. 23, 2004, the contents of which is incorporated by reference herein in its entirety.

The preceding details of the loader102are presented for exemplary purposes only. The cover system10can be used to facilitate the transfer of particulate substances to systems and devices other than the loader102. For example, the cover system10can be used to facilitate the transfer of particulate substances to delivery vehicles, reactor units, mixers, or storage containers. Moreover, the cover system10can be used to facilitate the transfer of particulate substances to loaders that can be connected to no more than one of the drums12at any one time.

The cover14of the cover system10is configured to securely mate with the drum12. In particular, the cover14has a lip20that engages a rim22formed around the upper edge of the drum12. The lip20and the rim22are depicted inFIGS. 3 and 6. The cover system10can include a compression ring18that engages the lip20and the rim22. The compression ring18can be tightened around the lip20and the rim22by a fastener or other suitable means that draws opposing ends of the compression ring18together. The compression ring18, when tightened, drives the lip20and the ring22together, thereby securing the cover14to the drum12and substantially sealing the interface between the cover14and the drum12.

The use of the compression ring18to secure the cover14to the drum12is disclosed for exemplary purposes only. Other types of securing means, such as fasteners or clamps, can be used in the alternative.

The cover system10includes features that permit the catalyst and/or additive11to be drawn out of the drum12while the cover14is installed on the drum12. In particular, the cover14has a first penetration point or opening26formed therein. The first opening26is preferably located proximate an outer perimeter of the cover14, as shown inFIG. 6.

The system10further includes a fitting28having a first end28aand a second end28b, as shown inFIG. 1. The fitting28has a flow path defined therein and extending between the first and second ends28a,28b. The diameter of the flow path can be approximately two inches. The optimal value for the diameter of the flow path is application dependent, and can vary with factors such as the maximum desired rate at which the catalyst and/or additive11is to be unloaded from the drum12; a specific value for the diameter is disclosed for exemplary purposes only.

The fitting28is attached to the cover14so that the fitting28extends through the port26, and a portion of the fitting28projects downward into the volume25when the cover14is mounted on the drum12. The first end28aof the fitting28is located within the volume25, and the second end28bis accessible from the exterior of the drum12and the cover14when the cover14is mated with the drum12.

The fitting28can be attached to the cover14using threaded rings30that engage complementary threads formed on the fitting28as shown, for example, inFIG. 1. Gaskets (not shown) or other suitable means can be used to seal the interface between the rings30, the cover14, and the fitting28. Other permanent, semi-permanent, and non-permanent means for securing the fitting28to the cover14can be used in the alternative; for example, a plastic insert that securely engages the fitting28and the periphery of the first opening26can be used in lieu of the threaded rings30.

The fitting28is depicted as substantially elbow-shaped for exemplary purposes only. Fitting having other shapes, including substantially straight fittings, can be used in the alternative.

The system10can also include a wand33formed from a length of tubing, as shown inFIGS. 1 and 7. A first end33aof the wand33can be connected to a first end of a nipple35(depicted inFIG. 7) by a suitable means such as clamps or threads (not shown). A second end of the nipple35can be connected to the fitting28by a suitable means such as clamps or threads, so that the wand33is in fluid communication with the fitting28. The wand33can be connected to the fitting28using other means in alternative embodiments. The wand33can be connected directly to the fitting28in other alternative embodiments.

The inner diameter of the wand33can be approximately two inches. The optimal value for the inner diameter of the wand33is application dependent, and can vary with factors such as the maximum desired rate at which the catalyst and/or additive11is to be unloaded from the drum12; a specific value for the inner diameter is disclosed for exemplary purposes only.

The length of the wand33is preferably chosen so that a second end33bof the wand33is located proximate a bottom surface12aof the drum12when the cover14is installed on the drum12, as shown inFIG. 1. Preferably, the lowermost point of second end33bis located not more that approximately one-half inch from the bottom surface12awhen the cover14is installed on the drum12.

The second end33bof the wand33is preferably angled in relation to the longitudinal axis of the wand33, as depicted inFIGS. 1 and 7. This feature can increase the effective area through which the catalyst and/or additive11is drawn into the wand33. Moreover, it is believed that the angled orientation of the second end33bin relation to the bottom surface12aof the drum12can minimize the potential for the opening defined by the second end33bto become plugged with the catalyst and/or additive11. Also, the angled orientation of the second end33bis believed to reduce the potential for a vacuum lock to form between the second end33band the bottom surface12a.

One or more holes are preferably formed in the wand33, proximate the first end33a. Most preferably, four circular holes34are formed in the wand33at equally-spaced angular positions around the circumference of the wand33, as shown inFIGS. 1 and 7. Each of the holes34preferably has a diameter of approximately 0.25 inch (6.4 mm), and is preferably located approximately 0.75 inch (19.1 mm) from the cover14when the wand33is installed on the cover14. The holes34, it is believed, can act as vacuum relief ports that further reduce the potential for a vacuum lock to form between the second end33bof the wand33and the bottom surface12aof the drum12.

Specific values for the diameter of the holes34, and for relative positions of the holes34on the wand33are presented for exemplary purposes only; the holes34can be sized and positioned differently in alternative embodiments. Moreover, the holes34can have a shape other than circular in alternative embodiments.

The fitting28can mate with an associated one of the hoses138using clamps, couplings, or other suitable means. As discussed above, the hose138can be connected to an associated valve142of the loader102. The hose138, fitting28, and wand33thus place the internal volume126of the dust collector116in fluid communication with the volume25defined by the drum12and the cover14.

The use of the hose138to place the volume25in fluid communication with the loader102is disclosed for exemplary purposes only. Other suitable conveying means, such as hard piping, can be used in the alternative. Moreover, multiple lengths of hose connected by fittings or other suitable means can be used in lieu of the single hose138.

Alternative embodiments of the cover system10can include a membrane61of sealable material, as shown inFIGS. 10A and 10B. The membrane61can be secured to the cover14so that the membrane61spans the opening26. The sealable material of the membrane61can be pierced by the second end33bof the wand33as the wand33is inserted through the opening26after the cover14has been placed on the drum12, as denoted by the arrows65inFIGS. 10A and 10B. The sealable material is sufficiently resilient, malleable, and/or controllable to create a seal between the outer circumference of the wand33and the remaining portion of the membrane61. The use of the membrane61can obviate the need to secure the fitting28to the cover14using the rings30.

The system10preferably includes a vacuum relief mechanism40. The vacuum relief mechanism40can be attached to a fitting41. The fitting41can extend through a second penetration point or opening42formed in the cover14and shown inFIG. 6, so that the vacuum relief mechanism40is in fluid communication with the volume25by way of the fitting41.

The fitting41can be secured to the cover14using a suitable means such as threaded rings44that engage complementary threads formed on the fitting41as shown, for example, inFIG. 1. Gaskets (not shown) or other suitable means can be used to seal the interface between the rings44, the cover14, and the fitting41. Other means for securing the fitting41to the cover14can be used in the alternative, including, for example, a plastic inset that securely engages the fitting41and the periphery of the second opening42.

The vacuum relief mechanism40can include, for example, a housing47and a fitting59attached to the housing, as shown inFIGS. 8A and 8B. The housing47has an internal passage49formed therein. The fitting59includes a screen45. The fitting59is positioned on the housing47so that the screen45spans one end of passage49. The screen45can be, for example, a 40-mesh screen; screens having a mesh other than 40 can be used in the alternative.

A first end of the housing47is connected to the fitting41by a suitable means such as threads, so that the passage49is in fluid communication with the internal volume25of the drum12. An elbow55can be connected to the second end of the housing47. The elbow55faces downward, to discourage the influx of contaminates such as rain through the vacuum relief mechanism40.

The screen45permits air from the ambient environment to enter the internal volume25by way of the passage49and the fitting41, while preventing the influx of foreign matter such as leaves, rodents, etc. The vacuum relief mechanism40thus acts as a vacuum breaker that can help to ensure that the pressure differential between the internal volume25and the ambient environment does not exceed the structural limits of the drum12or the cover14.

The use of a vacuum relief mechanism40employing a screen is disclosed for exemplary purposes only. Other types of vacuum relief mechanisms can be used in the alternative.

The fitting41is preferably configured to accommodate a vacuum gauge46that provides an indication of the vacuum within the volume25as the drum12is being unloaded. The vacuum gauge is depicted inFIGS. 1-5.

The fitting41can also be configured to accommodate a pressure relief valve51shown inFIGS. 1-5. The fitting41can be a T-shaped fitting that places each of the vacuum gauge46, the pressure relief valve51, and the vacuum relief mechanism40in fluid communication with the internal volume25. A first end of the pressure relief valve51can be connected to the fitting41by a suitable means such as threads. An elbow63can be connected to a second end of the pressure relief valve51, to discourage the influx of contaminates such as rain.

The pressure relief valve51can relieve the pressure within the internal volume25when the pressure within the internal volume exceeds the pressure of the ambient air by a predetermined amount. This situation can occur, for example, when the drum12inadvertently pressurized, or when the catalyst and/or additive11within the drum12becomes heated, causing evaporation of volatiles from the catalyst and/or additive11. A pressure relief valve suitable for use as the pressure relief valve51can be obtained, for example, from Circle Seal Controls, Inc., of Corona, Calif. as the 500 Series Adjustable Popoff & Inline Relief Valve.

Alternative embodiments of the cover system10can be configured without the vacuum relief mechanism40, the vacuum gauge46, and/or the pressure relief valve51.

The use of a T-shaped fitting41to accommodate the vacuum gauge46, the pressure relief valve51, and the vacuum relief mechanism40is disclosed for exemplary purposes only. Other types of fittings can be used in the alternative. Moreover, each of the vacuum gauge46, the pressure relief valve51, and the vacuum relief mechanism40can be accommodated by its own individual fitting mounted on the cover14, in alternative embodiments.

The internal volume25can be placed in fluid communication with a source of a gas, such as nitrogen, that will not react with the catalyst and/or additive11. This feature can permit the volume25to be filled with a blanket of nitrogen gas as the catalyst and/or additive11is drawn out of the drum12. The connection with the source of nitrogen gas can be facilitated by, for example, a fitting53mounted on the cover14, and a length of hose139connected to the fitting41as depicted inFIGS. 1-5. The fitting53can extend through the cover14by way of a port or opening57formed therein; the opening57is depicted inFIG. 6. Alternative embodiments of the cover system10can be configured without the fitting53and the hose139.

The system10preferably includes a means for supporting the drum12in a tilted orientation as the drum12is unloaded. For example, the system10can include a cradle50, depicted inFIG. 1. The cradle50is preferably configured so that a longitudinal or central axis “C1” of the drum12is angled less than approximately ninety degrees in relation to the vertical direction when the drum12is positioned on the cradle50. More preferably, the cradle50is configured so that the longitudinal axis C1is angled between approximately twenty to approximately sixty degrees in relation to the vertical direction.

Tilting the drum12can help ensure that a substantial entirety of the catalyst and/or additive11is drawn out of the drum12. More particularly, the drum12is preferably positioned on the cradle50so that the second end33bof the wand33is located at approximately the 6:00 o'clock position, when viewed from a perspective rotated ninety degrees from the perspective ofFIG. 1. Moreover, the first opening26is located proximate the outer perimeter of the cover14, as noted previously. This feature helps to position the second end33bof the wand33proximate the lowest point of the drum12when the drum12is oriented as noted.

The tilted orientation of the drum12causes the catalyst and/or additive11in the drum12to be drawn toward the lowest point of the drum12by gravity as the drum12is emptied. Positioning the second end of the wand33bproximate the lowest point of the drum12can thus help to ensure that a maximal amount of the catalyst and/or additive11is drawn out of the drum12.

The use of the cradle50to support the drum12in a tilted orientation is disclosed for exemplary purposes only. Other means for tilting the drum12can be used in the alternative. For example, the drum12can be placed on a ramp having an inclined surface. As a further example, the drum12can be placed on a hand-truck or other carrying device and held in a tilted orientation during the unloading process.

The drum12can be used to hold the catalyst and/or additive11during transport to the refinery or other point of use, i.e., the drum12can be used as a shipping container. The drum12can also be used to store the catalyst and/or additive11at the refinery or other point of use until the catalyst and/or additive11is needed. A conventional cover can be installed on the drum12during shipping and storage.

The drum12can be moved to a location at which the hose138can be connected to the fitting28. Alternatively, the hose138can be connected to the drum12where the drum12is stored, thereby obviating the need to move the drum12from the storage area.

The cover used for shipping and storage can be removed from the drum12. The cover14, with the fitting28, wand33, vacuum relief mechanism40, fitting41, pressure relief valve51, and vacuum gauge46mounted thereon, can then be installed as depicted, for example, inFIGS. 2-5. The cover12can be moved with a side to side or circular motion help drive the wand33downward into the catalyst and/or additive11.

In alternative embodiments equipped with the membrane61of sealable material, the wand33can be inserted through the membrane61and into the catalyst and/or additive11after the cover14has been placed on the drum12. The sealable material, a discussed above, is pierced by the wand33, and forms a seal around the outer circumference of the wand33.

The compression ring18can be installed once the cover14has been placed on the drum12. The compression ring18can be tightened to drive the lip20of the cover14and the ring22of the drum12together, substantially sealing the interface between the cover14and the drum12. The hose138can be connected to the fitting28, to place the internal volume25in fluid communication with the loader102. The hose139can be connected to the fitting53to place the internal volume25in fluid communication with the source of nitrogen, if the cover system10is configured to provide a nitrogen blanket within the internal volume25during the unloading process.

The drum12is preferably placed on the cradle50or other supporting means after the cover system10has been installed, to help minimize the possibility of spillage of the catalyst and/or additive11during the installation process.

The hose138, as discussed above, is in fluid communication with a vacuum source, such as the dust collector116of the loader102, on a selective basis. The valve142of the loader102can be opened when the electronic controller of the loader102determines that the injection sequence for the particular catalyst and/or additive11in the drum12is to commence. The vacuum within the dust collector116draws the particulate substance from the drum12by way of the hose138, fitting28, and wand33. The path of travel of the catalyst and/or additive11is denoted by the arrows143inFIGS. 1 and 9.

The fitting53and the hose139allow the nitrogen gas to be drawn into the volume25within the drum12as the catalyst and/or additive11is removed. The path of travel of the nitrogen gas is denoted by the arrows147inFIG. 1. Replacing the catalyst and/or additive11with a blanket of nitrogen gas can reduce the potential for contamination of the catalyst and/or additive11, particularly in applications where the entire amount of the catalyst and/or additive11in the drum12is not transferred to the loader102in a single operation, i.e., where some of the catalyst and/or additive11remains in the drum12for transfer at a later time.

One, or more than one of the drums12can be connected to the loader102at one time, as discussed above. If desired, three cover systems10can be installed on three drums12that each hold a different type of catalyst and/or additive11. The catalyst and/or additive11can be transferred to the loader10from each of the three drums12on a sequential basis, using the above-described process.

The cover system10can permit a particulate substance, such as the catalyst and/or additive11, to be unloaded from a container, such as the drum12, without damaging the container due to an excessive pressure differential between the interior of the container and the ambient environment. Unloading a container while it is covered can substantially reduce the potential for fugitive emissions and other losses of the particulate substance during the unloading process. Unloading a container in this manner can also reduce the potential for human exposure to the particulate substance. Eliminating human exposure and fugitive emissions can be particularly beneficial, for example, in applications where the particulate substance is toxic, caustic, or otherwise harmful to humans or the environment.

Moreover, the ability to unload a container while the particulate substance therein is substantially isolated from the ambient environment can minimize the potential for contamination of the particulate substance. The use of the cover system10can thus be especially beneficial, for example, in applications where the particulate substance possesses hygroscopic properties. More specifically, the cover system10, by isolating the particulate substance from the ambient environment, can minimize or substantially eliminate the absorption of water by a hygroscopic material during the unloading process.

By “hygroscopic,” it is meant having the property of absorbing atmospheric moisture. Hygroscopic materials include, but are not limited to, food products, pharmaceuticals and industrial chemicals, as well as catalyst and/or additives, e.g., FCC catalysts and/or additives.

The ability of the cover system10to substantially isolate a particulate substance within a container from the ambient environment can also be beneficial, for example, in applications where the particulate substance possesses pyrophoric, i.e., spark or flame inducing, properties. It should be noted that the cover system10can be used in connection with particulate substances other than pyrophoric and/or hygroscopic materials.

The use of the cover system10can permit the particulate substance to be transferred directly to its point of use, e.g., the loader102, without a need to transfer the particulate substance to an intermediate vessel from which the particulate substance is subsequently be transferred.

The cover system10is believed to be particularly well suited for use with relatively small, mobile loaders, such as the loader102, as these types of loaders are well suited to draw particulate matter from storage drums rather than large storage hoppers or rail cars. Moreover, the use of the cover system10can permit one or more of the drums12to be unloaded at a site remote from the loader102, in relatively quick succession. It should be noted that the cover system is not limited to use with small, mobile loaders; the cover system10can be used in connection with relatively large and/or stationary loaders.

The foregoing description is provided for the purpose of explanation and is not to be construed as limiting the invention. Although the invention has been described with reference to preferred embodiments or preferred methods, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Furthermore, although the invention has been described herein with reference to particular structure, methods, and embodiments, the invention is not intended to be limited to the particulars disclosed herein, as the invention extends to all structures, methods and uses that are within the scope of the appended claims. Those skilled in the relevant art, having the benefit of the teachings of this specification, may effect numerous modifications to the invention as described herein, and changes may be made without departing from the scope and spirit of the invention as defined by the appended claims.