DESCRIPTION
METHOD AND APPARATUS FOR A RAIL-MOUNTED CONCRETE MIXER AND PUMP SYSTEM
BACKGROUND OF THE INVENTION
This application claims priority on provisional patent application Serial No. 60/110,293 filed November 30, 1998, entitled "Method and Apparatus For A Rail-Mounted Concrete Mixer And Pump System," by Edwin deSteiguer Snead. The entire text of the above-referenced disclosure is specifically incorporated by reference herein without disclaimer.
1. FIELD OF THE INVENTION The present invention relates generally to a binder or adhesive material transportation system, and, more particularly, to a rail-mounted concrete mixer and pump system.
2. DESCRIPTIONOFTHERELATEDART Transporting bulk materials by rail has long been recognized as a cheaper alternative to transporting such materials by road. With rail transportation, large quantities of material can be moved using a small crew at relatively low cost. For example, a train with a two-man crew pulling 1,600 net tons of material at 55 m.p.h. would produce approximately thirty-two times as many ton-miles per hour as a dump truck with a driver hauling 25 tons at 55 m.p.h. Accordingly, a train is able to carry a much greater amount of material in a more efficient manner than transporting the material via road transportation with a dump truck, for example.
In addition to the greater amount of material that a train can carry over a dump truck in a single load, the train also has the advantage of being less subject to inclement weather conditions, that generally impede transportation by roadway. For example, rain and snow generally slow and may sometimes completely halt transportation by roadway due to unsafe
driving conditions. However, since a train runs on a track, it is much less prone to the slick driving conditions often encountered via road transportation. Accordingly, rail transportation is typically more reliable than road transportation during poor weather conditions. Moreover, in many cases, access to remote locations is limited by the lack of adequate roads to the job site, thus necessitating rail travel for materials.
The transport of ready-mix concrete is also hindered by the limited life of the cement after water is added. Even if the cement and aggregate components are separated from the water until arrival at the job site, some of the cement is spoiled by the moisture normally present in the stockpiles.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.
SUMMARY OF THE INVENTION
In a first aspect, the invention is a rail-mounted car for mixing and pumping binder or adhesive materials comprising a hopper to receive a cement mixture including aggregate; a screw conveyor connected to the hopper and adapted to mix the cement mixture received from the hopper with water to produce concrete; an articulated boom; and a pump adapted to pump the concrete through the boom.
In a second aspect, the invention is a method for transporting binder or adhesive materials by a rail-mounted train comprising: mixing sand and gravel; heating the mixture inside a drier; weighing the mixture; adding cement to the mixture; and restricting moisture from contaminating the mixture. A cement and aggregate mixture is processed prior to mixing with water to reduce its moisture content. The mixture is transported in a rain-proof container car, such as a hopper car, to the desired site.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which:
FIG. 1 depicts a concrete mixing and pumping system in accordance with one embodiment of the present invention;
FIG. 2 shows the detail of a hopper car, which forms a part of the system in FIG. 1 ; FIG. 3 shows a cross-sectional view of the hopper car of FIG. 2; FIG. 4 depicts the detail of a material transfer car that forms a part of the system of FIG. l;
FIG. 5 shows a side view of the mixer car, which forms part of the system in FIG. 1 ;
FIG. 6 illustrates a process for producing cement at a hot mix plant in accordance with one embodiment of the present invention; FIG. 7 illustrates one variant of the embodiment in FIG. 6 as may be implemented with the system of FIGS. 1-5; and
FIG. 8 illustrates a second variant of the embodiment in FIG. 6 as may be implemented with the system of FIGS. 1-5.
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous
implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nonetheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.
Turning now to the drawings, and specifically referring to FIGS. 1 and 5, the invention in a first aspect is a rail-mounted car 115 for mixing and pumping binder or adhesive materials generally comprising: a hopper 135 to receive a cement mixture 106 including aggregate; a screw conveyor 140 connected to the hopper 135 and adapted to mix the cement mixture 106 received from the hopper 135 with water to produce concrete; an articulated boom 150; and a pump 145 adapted to pump the concrete through the boom. In various alternative embodiments, the articulated boom 150 is hydraulically powered, electrically powered, or pneumatically powered. Also in various alternative embodiments, the cement mixture is dehydrated prior to mixing with water or remains hydrated. In this context, hydrated simply means that the powdered cement or cement mixture has not been dried to remove moisture accumulating therein through routine environmental exposure.
The rail-mounted car 115 may also be employed in various alternative embodiments as part of a rail-mounted binder or adhesive material mixing and pumping system such as the system 100 shown in FIG. 1. The system 100, in the particular embodiment of FIG. 1 , comprises a hopper car 105; a material transfer car 120 adapted to transfer a cement mixture 106 from the hopper car 105 to a mixer car 115. The mixer car 115, as discussed above, includes a hopper 135; a screw conveyor 140 connected to the hopper 135 and adapted to mix the cement mixture 106 with water to produce concrete; an articulated boom 150; and a pump 145 adapted to pump the concrete through a pipe supported by the boom.
In a second aspect of the invention, there is a method for transporting binder or adhesive materials, and, more particularly, cement mixtures by a rail-mounted train. This method, in the particular embodiment shown in FIG. 6, comprises: mixing sand and gravel as shown in box 505, drying the mixture as shown in box 510, weighing the mixture as shown in box 515; adding
cement to the mixture as shown in box 520; and restricting moisture from contaminating the mixture as shown in box 525. In various alternative embodiments, the method 500 may include any one or more of loading the mixture into the hopper car, sealing the hopper to restrict moisture contamination, and transporting the mixture in the hopper car. In some alternative embodiments, the hopper car may be coupled to a material transfer car which is further coupled to a mixer car.
Referring now more particularly to the particular embodiment of FIGS. 1-5, the system 100 with concrete mixing and pump capabilities is shown in accordance with one particular embodiment of the present invention. The system 100 is part of a rail-mounted train powered by a conventional locomotive engine (not shown), and includes a plurality of hopper cars 105 for transporting bulk materials. The number of hopper cars 105 coupled to the train could vary depending on the amount of material that is to be transported by the train 100, as well as the capability of the engine to haul the particular number of hopper cars 105 at full payload.
Turning now to FIG. 2, a side view of one of the hopper cars 105 is shown in detail. The hopper cars 105 each include a coupler 205 on their front and back end to couple the hopper cars 105 to adjacent cars. The coupler 205 on the front end of the first hopper car 105 serves to couple the hopper cars 105 of the train 100 to the engine.
In the illustrated embodiment, each hopper car 105 includes two hoppers 210 for carrying the material that is transported by the train 100. However, it will be appreciated that each hopper car 105 may be configured to have any desired number of hoppers 210, and need not be limited to two hoppers 210. The bulk materials carried by the hoppers 210 is a mixture of cement with sand and gravel in one embodiment. However, it will be appreciated that many different kinds of binder or adhesive materials (e.g., masonry cement, oil well cement, gypsum plasters, lime mortars, calcium aluminate cement, trief cement, supersulfated cement) could be transported on the train 100. The cement mixture 106 is processed at a hot mix plant (not shown) prior to loading in the hoppers 210. It will be appreciated that in other embodiments of the present invention, the cement mixture 106 can be processed on the train 100 or at a remote site prior to mixing with water. The process by which the cement mixture 106 is prepared at the hot mix
plant is explained below.
When viewed from the top, the hoppers 210 are rectangular in shape, and include planar end walls 215 and planar side walls 220. The walls 215, 220 of the hopper 210 are inclined at shallow angles to the vertical (i.e., sloped) to effect a complete discharge of the bulk material contained therein by gravity action. The hoppers 210 are supported by a pair of side sills 225 that extend the length of the hopper car 105, and by vertical posts 230, which bear on longitudinal stringers 235 that are secured to the side walls 220.
In accordance with one embodiment, the hopper cars 105 include covers 110 (as shown in
FIG. 1), which prevent precipitation from coming in contact with the cement mixture while inside the hoppers 210. In one embodiment, the covers 110 are attached to the hoppers 210 via hinges (not shown), and are hinged along one of the top edges of the side walls 220. In this particular embodiment, the covers 110 will open and close the top portion of the hoppers 210 in a "clamshell" fashion. That is, when loading the hoppers 210 with the cement mixture 106, the cover 110 is raised to provide access to the hopper 210 on one end, and subsequently lowered to completely seal the hopper 210 and protect its contents from the environment. Alternatively, in accordance with another embodiment, the covers 110 could be configured so as to be completely removable from the top portion of the hoppers 210 for loading the cement mixture 106 into the hopper 210, and then placed atop the hopper 210 and affixed thereto via any one of several types of commercially available fasteners.
Turning now to FIG. 3, a cross-sectional view of the hopper car 105 is shown. The bottom portion of the hopper 210 includes a "clamshell" gate 305, which consists of a pair of coacting gate members 310 pivotally mounted for movement between a closed position (as illustrated in FIG. 3) and an open position. The gate members 310 pivot between the open and closed positions via a pair of pivot points 315. A pair of hydraulic cylinders 320 power the gate members 310 into the open and closed positions. Each hydraulic cylinder 320 is coupled between the outer edge of the gate members 310 and the side walls 220 of the hopper 210. In one embodiment, the hydraulic cylinders 320 are double-acting cylinders controlled by suitable four-way control valves. In accordance with one embodiment, the control valves may be manual
valves mounted on the car structure, to enable an operator to move along side the train 100 and open the gates 305 for the several hoppers 210 in a sequential manner.
When the gate members 310 are in the open position, the cement mixture 106 pours from the hopper 210 onto a conveyor 325 that runs the entire length of the plurality of hopper cars 105 of the train 100. The conveyor 325 is an endless belt conveyor consisting of an upper supply run 330 and a lower return run 340. The return run 340 of the conveyor 325, in accordance with one embodiment, is supported in a plane disposed as close as possible to the upper surface of a wheel axle 345, which couples two rail wheels 350 to the hopper car 105. Alternatively, the return run 340 of the conveyor 325 could be supported by a set of return idlers (not shown). The upper supply run 330 of the conveyor 325 is supported by troughing idlers 355. To support the upper run 330 as low as possible, and, thus, as close as possible to the lower return run 340, the troughing idlers 355 are supported in a catenary fashion by chains 360. The chains 360 are supported by a set of brackets 365 secured to the side sills 225 of the hopper car 105. As mentioned, the train conveyor 325 traverses the entire length of the hopper car portion of the train 100. The hopper cars 105 are suitably provided with support structures (not shown) for supporting the conveyor 325 between the hopper cars 105. When it is desired to unload the cement mixture 106 from the hoppers 210, the clamshell gates 305 of each of the hoppers 210 are opened, and the cement mixture 106 pours out of the bottom of the hoppers 210 onto the conveyor 325. The conveyor 325 then facilitates moving the cement mixture 106 to one end of the train 100.
Referring again to FIG. 1, the train 100 includes a mixer car 115 coupled to one end thereof. The cement mixture 106 from the hopper cars 105 is transferred to the mixer car 115 via the train conveyor 325. The hoppers 210 may be emptied in sequence beginning with the hopper 210 of the hopper car 105 nearest (or adjacent to) the mixer car 115.
Coupled between the last hopper car 105 of the chain of hopper cars 105 and the mixer car 115 is a material transfer car 120, which is shown in detail in FIG. 4. The material transfer car 120 includes an elevated conveyor track 405, which elevates the conveyed material from the conveyor 325 from the hopper cars 105 for discharge onto a transfer conveyor 410. The elevated
conveyor track 405 is supported by a support frame structure 415 for maintaining the elevated conveyor track 405 at a predetermined angle relative to the surface of the material transfer car 120.
The transfer conveyor 410 is an endless belt conveyor, which is mounted on the backend portion of the material transfer car 120. The forward end of the transfer conveyor 410 is supported by a post 420, which lies under the rearward portion of the elevated conveyor track 405. The middle portion of the transfer conveyor 410 is supported by a hydraulic lift cylinder 425, which raises and lowers the transfer conveyor 410 to a suitable height for transferring the bulk material (i.e., the cement mixture) to the mixer car 115. In one embodiment, the transfer conveyor 410 is provided with a hydraulically powered device (not shown) for rotating the transfer conveyor 410 relative to the axis of the post 420. In this embodiment, the discharge end of the transfer conveyor 410 can be positioned where desired (e.g., off to the side of the material transfer car 120) in order to discharge material from the transfer conveyor 410 onto another transport vehicle (not shown), for example. In the illustrated embodiment, however, the cement mixture 106 is transferred from the transfer conveyor 410 directly to the mixer car 115.
In accordance with one embodiment, the material transfer car 120 may be provided with a power generating apparatus for operating the belt conveyor system (i.e., the train conveyor 325, elevated conveyor track 405, and transfer conveyor 410). The belt conveyor system; which consists of the aforementioned conveyors, is driven by electric motors (not shown), and the power for the electric motors may be generated by an electric generator 430, driven by an internal combustion engine 435, such as a diesel engine, for example. The electric generator 430 may also provide power for auxiliary apparatus, such as the mixer car 115, which may be used in conjunction with the material transfer car 120. Additionally, high pressure hydraulic fluid for the operation of the hydraulic cylinders 320 on the hopper car 105, to operate the "clamshell" gate 305 of the hopper 210, may be supplied from the material transfer car 120, which would include a suitable electric motor driven hydraulic pump (not shown).
The mixer car 115, as shown in FIG. 5, includes a hopper 135, which receives the cement mixture 106 from the transfer conveyor 410 of the material transfer car 120. The hopper 135,
along with a concrete mixing screw conveyor 140, mixes the cement mixture 106 with water to produce the concrete. The water supplied to the hopper 135 and screw conveyor 140 could come from a "water car" (not shown) that is coupled to the other end of the train 100. That is, the end of the train 100 proximate to the locomotive engine. Alternatively, the water may be supplied locally from the point where the concrete is laid.
The mixer car 115 is further provided with a concrete pump 145, which receives the concrete via the concrete mixing screw conveyor 140, and forces the concrete through a powered articulated boom 150. The boom 150 is extendible and retractable, and rotates about its base, permitting a greater range of mobility and distance for laying the concrete proximate to the train 100. In one embodiment, the boom 150 is powered by hydraulics. In other embodiments, the boom 150 can be electrically or pneumatically powered.
Cement processing typically consists of quarrying and crushing the rock, grinding the proportioned materials to high fineness, subjecting the raw mix to pyroprocessing in a kiln, and grinding the resulting clinker to a fine powder. A fuller discussion of cement processing such as generally comprises the state of the art can be found in KIRK-OTΉMER, ENCYCLOPEDIA OF CHEMICAL TECHNOLOGY (3d ed. 1979). However, aggregates combined with the cement to form concrete, such as sand and gravel, are not included in cement processing.
Turning now to FIG. 6, a process 500 is shown for preparing the cement to be carried on the train 100. The process 500 commences at step 505 where sand and gravel are mixed. The mixture is then run through a drier at step 510. The drier raises the temperature of the sand and gravel to approximately 250 degrees Fahrenheit in one embodiment. By heating the sand and gravel to approximately 250 degrees Fahrenheit, the resulting moisture content of the sand and gravel is approximately less than one percent. At step 515 the sand and gravel mixture is weighed. Then at step 520 the mixture is combined with dry cement in the proper proportions for an eight cubic yard batch in accordance with one embodiment. At step 525 moisture is restricted from contacting the 8-yard batches of the cement mixture.
Alternatively, as opposed to mixing the cement with the sand and gravel mixture at the hot mix plant, the train 100 could carry the cement and the sand and gravel mixture separately. That is, the cement could be carried by its own designated hopper cars 105 and the sand and gravel mixture could be carried in their own separate hopper cars 105.
In operation, the hoppers 210 of the train 100 are loaded with the cement mixture 106 after the mixture is processed by the hot mix plant. As previously mentioned, in one embodiment, covers 110 are placed atop the hoppers 210 to restrict moisture from contacting the cement mixture 106 during transport to a desired location.
The train 100 transports the cement mixture 106 to a location where it is desired to lay concrete. Upon arrival at such location, the hoppers 210 of the hopper cars 105 are sequentially emptied. Typically, the car closest to and/or adjacent to the mixer car 115 is emptied first. The hoppers 210 could be emptied either manually or automatically. That is, in one embodiment, a control panel (not shown) could be used such that a crew member could manually discharge the contents of each hopper 210. Alternatively, such discharge could be performed automatically by causing the "clamshell" gates 305 of each hopper 210 to open sequentially for a predetermined time period to allow the contents of the hopper 210 to fully discharge.
Once the hoppers 210 begin to discharge the cement mixture 106, the train conveyor 325 transports the cement mixture 106 to the material transfer car 120. The material transfer car 120 receives the cement mixture 106 from the train conveyor 325 on the elevated conveyor track 405, which transfers the cement mixture 106 to the transfer conveyor 410. The transfer conveyor then elevates the cement mixture 106 for transfer to the mixer car 115. The mixer car 115 receives the cement mixture 106 in the hopper 135, which transfers the cement mixture 106 to the concrete mixing screw conveyor 140. The concrete mixing screw conveyor mixes the cement mixture 106 with water and transfers the mixed concrete to the concrete pump 145. As previously mentioned, the water could be supplied to the concrete mixing screw 140 from a "water car" (not shown) on the other end of the train 100. The concrete pump 145 then forces the concrete through an articulated boom for laying the concrete at the desired location.
The system 100 of FIGS. 1-5 may be employed to perform one variant embodiment of the method 500 in FIG. 6 as set forth in FIG. 7. Referring now to FIG. 7, a method 600 for transporting binder or adhesive materials, and, more particularly, cement mixtures by a rail- mounted train is shown. The method 600 begins with mixing sand and gravel as shown in box 605; continues with drying the mixture as shown in box 610; weighing the mixture as shown in box 615; adding cement to the mixture as shown in box 620; loading the mixture into a hopper car as shown in box 625; and transporting the loaded cars as shown in box 630. Again, in various alternative embodiments of the method 600, the hopper may be sealed to restrict moisture contamination or may be coupled to a material transfer car which may be coupled to a mixer car.
The system 100 of FIGS. 1-5 may also be employed to perform a second variant embodiment of the method 500 in FIG. 6 as set forth in FIG. 8. The method 700 begins by mixing sand and gravel as shown in box 705; and then continues by drying the mixture as shown in box 710; weighing the mixture as shown in box 715; adding cement to the mixture as shown in box 720; loading the mixture into a hopper car as shown in box 725; transferring the mixture from the hopper car to a mixer car as shown in box 730; mixing the mixture with water to produce concrete as shown in box 735; and pumping the concrete through an articulated boom as shown in box 740. The method 700 may also be performed with the articulated boom affixed to the mixer car and may include sealing the hopper car to restrict moisture contamination.
Thus, the invention as set forth above provides, in its various embodiments, a method and apparatus for a rail-mounted binder or adhesive material mixer and pump system. In one aspect of the present invention, a method is provided for transporting and mixing binder or adhesive materials by a rail-mounted train. A cement and aggregate mixture is processed prior to mixing with water to reduce its moisture content. The mixture is transported in a rain-proof hopper car to the desired site. In another aspect of the present invention, a rail-mounted mixer car for mixing and pumping binder or adhesive materials includes a powered articulated boom. The boom permits a greater range of mobility and distance for pumping the binder or adhesive material proximate to the mixer car.
The particular embodiments disclosed above are, however, illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.