Patent Application
20060162608
This invention relates to a method and apparatus for moving bulk materials that can be moved in conventional trains, trucks, conveyor belts, aerial tramways or as a slurry in a pipeline. All of the above methods are commonly used in various industries because of site-specific needs or experience. In the minerals and aggregate industries, for example, bulk materials are moved from mining or extraction sites to a process facility for upgrading or sizing.
Trucks had been the system of choice for many years for moving bulk materials. Highway trucks are loud, dangerous, require high maintenance, and are not very popular with the public because of environmentally harmful emissions. Trucks were enlarged to off road vehicles, which are a more efficient transport of bulk materials because of increased capacity. These vehicles, however, are limited to site specific applications and are high capital cost items. Major off road trucks have evolved that require very wide roadways for passing each other, are not energy efficient per ton-mile of material transported, have limited hill climbing ability, and are dangerous because of potential of operator error as well as being environmentally unpleasant neighbors.
Trains have been used for many years for bulk material transport in hopper cars. Because of low friction, the use of free rolling iron or steel wheels on steel tracks they are very efficient users of energy but are limited in capacity relative to the drivers or locomotives required. Large tonnage long trains use multiple drivers that are heavy units, which dictate the weight of rail and ballast requirements. All railroads must be designed for the weight of the drivers or locomotives included fuel, not the combination of car plus loads, which are significantly less. The drivers need to be of sufficient weight so that the rotary drive wheel contact to the stationary rail have sufficient friction to produce forward or reverse movement. The inclination capable of conventional railroad systems is limited to the friction between the weighted drive wheels and track. Rail cars are individual units that each has to be loaded in a batch process, one car at a time. Bulk materials can be unloaded from hopper cars by opening bottom dump hatches or can be individually rotated to dump out of the top. Spotting cars for both loading and unloading is time consuming and labor intensive.
Although moving from point A to point B by railroad is cost effective the added cost of batch loading and unloading stages in shorter distance transports reduces the rail transport cost effectiveness. With normal single duel track train systems only one train can be used on a system at a time.
Conveyor belts have been used for many years to move bulk materials. A wide variety of conveyor belt systems exist that can move practically every conceivable bulk material. Very long distance single belt runs are very capital cost intensive and are subject to catastrophic failure when the belt tears or rips, shutting down the whole system and dumping the carried load, requiring cleanup. Conveyor belts are relatively energy efficient but can be high maintenance items because of the inherent problem of multiple idler bearings requiring constant checking and replacement. Short distance conveyor belts are commonly used in dry or damp transport of almost all types of materials. Because conveyor belts are very flexible and normally operated fairly flat they are not efficient at transporting moderately high solids slurry that water and fines can accumulate in low spots and spill over the side creating wet spilled slurry handling problems.
Some bulk materials can be transported in pipelines when mixed with water to form slurry that is pushed or pulled with a motor driven pump impeller in an airless or flooded environment. The size of the individual particles that are present in the bulk materials dictates the transport speed necessary to maintain movement. For example, if large particles are present then the velocity must be high enough to maintain movement by saltation or skidding along on the bottom of the pipe of the very largest particles. Because pipelines operate in a dynamic environment, friction is created with the stationary pipe wall by a moving fluid and solid mass. The higher the speed of the moving mass the higher the friction loss at the wall surface requiring increased energy to compensate. Depending on the application, the bulk material has to be diluted with water initially to facilitate transport and dewatering at the discharge end.
Light rail, narrow gage railroads for transporting bulk material from mines and the like is known from U.S. Pat. No. 3,332,535. Hubert et al, The patent show a light rail train made up of several cars propelled by drive wheels and electric motors combinations, dumping over an outside loop.
In U.S. Pat. No. 3,752,334. Robinson, Jr. et al. a similar narrow gage railroad is disclosed wherein the cars are driven by an electric motor and drive wheels.
In U.S. Pat. No. 3,039,402 Richardson, also showed a method of moving railroad cars using a stationary friction drive tire.
A review of the above described transport methods indicate that they all have specific advantages over the conventional systems, dependent on the application. It has become apparent however, that increases in labor, energy and material costs plus environmental concerns that alternate transport methods need to be applied that are energy and labor efficient, quiet, non-polluting, and esthetically unobtrusive. The light rail train utilizing an open semi-circular trough train of this invention with improved drive stations offers an innovative alternative to the above mentioned material transport systems.
Accordingly, it is an object of the present invention, aptly named Rail-Veyor by the inventor, to provide a method and apparatus for the efficient transport of bulk material that utilizes light rails similar to, but smaller than conventional railroad rails of sufficient capacity to support the carrier and the load. The invention comprises a combination of a railway train with equally spaced fixed site drivers for transporting bulk commodities. The train consists of a plurality of cars coupled together on a track way with each car having a longitudinal semi-circular trough adapted to contain said bulk commodities and each car having a pair of car length side drive plates, a pair of drive units mounted adjacent to and on both sides of said track way which consist of electrical motors, with gear reducers rotating horizontal flexible drive tires to provide a high friction contact with the said side drive plates to provide forward or reverse thrust, and an A/C inverter and controller connected to every pair of drive motors whereby the motor are synchronized and both the voltage and frequency can be raised or lowered as needed.
In the present invention there are external or off-track drives that are not physically connected to the moving train limiting the train weight to only the car and load weight reducing the need for costly ballast and sleepers to support the locomotives or drivers required in the conventional railroad comparison. For the purpose of this description light rails are those having a weight of 60 pounds or less per yard of length.
Another aspect of this invention is a method of transporting bulk commodities by a light rail train with external drives with the steps of coupling a plurality of railway cars together to form a train on a track way wherein each car has a longitudinal semi-circular trough adapted to contain the bulk commodities and each car has a pair of parallel car length side drive plates, loading said train with bulk commodities, driving said train with one or more pairs of stationary drive units mounted adjacent to said track way, and unloading the train by inverting the cars on an arcuate dual track way.
The cars, each consist of a semi-circle open trough and when joined or coupled together represents an open and continuous rigid trough for the entire length of the train. A flexible sealing flap attached near the front of the trailing car overlaps but is not attached to the rear of the lead car trough. A semi-circular trough is much better sealed with the flexible flap that other designs such as showed in U.S. Pat. No. 3,752,334. This allows the train to follow the terrain and curves without losing its sealed integrity as a continuous trough. The material to be transported in the train is effectively supported and sealed by this flap as the material weight is equally distributed maintaining the seal against the metal trough of the forward car. The long continuous trough provides for simplified loading as the train can be loaded and unloaded while moving similar to a conveyor belt. This is a significant advantage over the batch loading equipment requirements of a conventional railroad hopper or rotary dump car.
Each car will have a fixed side drive plate on each side, which runs the length of the car and spaced outside the wheels and tracks. These side drive plates are located symmetrically with the wheels and parallel to the light rails. Preferably, the centerline of the wheels will bisect the drive plates.
By providing two parallel sets of rails such as, an upper and lower sets of rails facing ball in, the train can operate inverted with the train hanging on the lower rail for unloading. Effectively, the train can make an outside loop with a double set of rails, which greatly simplifies unloading. After dumping, the inverted train can then be rotated back to the normal position eliminating the upper set of rails.
After the lead car, the individual cars have one set of wheels at the rear of the car and a single point connection to the car in front such as brackets with clevis pins. This allows the train to move in a flexible manner as well as vertically and actually rotate when operating in an inverted position to return to the normal operating condition. This ability to be less terrain sensitive than a conventional train adds to the flexibility of this light rail transport system.
The stationary drive stations consist of alternative current electric motors each coupled to a gear reducer which rotates a horizontal flexible drive tire which is in contact with the aforementioned side drive plates of the individual cars. Each station will consist of two or multiple of two drive units rotating in opposite directions on both sides of the cars. The A/C electric drive motors are controlled by inverters, which control all speed variations of the drive stations rotation and train movement as required. The inverter, controller and gear reducer design will allow operation of the station in reverse so the train can be programmed to move in both directions on the same track. This is important in single-track mining operations.
Each drive station motors operates in a vertical axis with the drive tire horizontal and contacting the side plates. Each drive station side is mounted to allow rotation around a fixed pivot shaft and be pivoted by an external screw-jack to control contact pressure of the side drive plate of the cars. This jack can be either electrically or mechanically controlled to provide the required opposing pressures to provide adequate forward or reverse thrust to move the train without slipping.
The drive stations are dormant when a train is not present. A sensor in the proximity of each drive station advises the drive unit to start when a train is approaching and starts up that drive. When a train completely passes the drive station a second sensor shuts the station down which is then waiting to be told to start up again with the arrival of the next train. The use of simple, off the shelf, A/C electric motors and gear reducers on the drives are operated in a benign environment, because of pre-train arrival startup, system shock requiring eventual maintenance is lessoned. Safety is improved as the energy to operate each drive is from an insulated power cable as opposed to the open third rail or overhead bare cable used in more typical electric drive trains.
Maintenance of the drive stations is simplified by the ease of removing a whole unit, when damaged, by lifting it off its pivot post and inserting a new or repaired unit. The side drive plates are designed to maintain continuity of tire to plate contact between cars by providing a projection in the lower part of the side plate and a matching recess in the lower part of the drive plate on the next car. It is preferred to use a semi-circular shaped projection but other shapes can be used if desired. The tire is always in contact with the upper part of the forward car plate when it comes in contact with the lower part of the following car plate. This design reduces open spaces between cars and reduces vibrations when the drive tire rotates from one car to the next.
These plates are also designed to allow short radius outside loops, between cars when unloading as well as space for turning or rotating as part of the operating process.
The wheels of each car are inside the side drive plates but outside the car frame. These wheels are located at the rear of each car connected to a single axle, which can be mounted through and attached to the frame. This allows for easy replacement of axles, bearings and wheels as a unit when the car is inverted, minimizing potential down time.
The flexible drive tires can be made out of a variety of materials. Examples of suitable material, but not limited to, are soft solid tires, synthetic rubber tires, urethane pneumatic rubber tires and synthetic foam filled tires. The preferred tire is a foam filled pneumatic tire. Foam provides the flex function associated with air filled tires without the potential problem of rapid deflation. The flexing capability compensates for irregularities in side plate spacing and also allowed for full contact of straight side plates even in deformed sections that would lead to contact skips with nonflexible tires. The use of a deflatable tire could cause a loss of traction and offer potential for derailment. The utilized tire will have a relatively low durometer surface that can adjust to the slight variable in the surface of the side plate providing positive traction. The drive tire and its wheel need to be permanently attached to avoid slippage during high torque startup when the train is loaded and idle, because of potential power outages and other physical stoppage of the train.
Forward or reverse motion of the train is the result of horizontal rotation of tires on opposite sides of the train turning in opposite directions with suitable pressure of said rotation that provides minimal slip between the tire surface and side plates. In other words, the two opposing tires are both pushed inward toward the center of the track.
The frictional forces of these drive tires—side drive plate contact is sufficient to avoid slippage between the drive tires and side plates, hence providing forward thrust. The system must have sufficient torque to meet the short-term maximum condition of a dead start of a fully loaded train. The required torque must be a minimum of twice that required during normal operations, and usually required for just a few seconds of time. The inverter provides this capability. The drive tire is mounted on a vertical shaft that is part of a gear reducer interconnected to an electric motor. This motor, gear reducer and tire unit or drive system is mounted on a post that is offset from the centerline of the drive system, which allows it to rotate around the vertical post. The vertical post is approximately the same distance from the car side plates as half of the diameter of the tire, with sufficient clearance allowed. This spacing allows for most efficient pressure when forces are applied to the side plates. Ideally, the pivot post, centerline of tire line is a 90° angle from the closest point on the drive plate.
Control of side pressure to maintain adequate friction between the side plate and tire is maintained by the placement of a second vertical post aligned perpendicular to the side plates of the cars and aligned with the drive tire. A tube containing a screw-jack type of devise is attached to the second vertical post that provides for movement and resultant pressure of the drive tire against the car drive plates. Side pressure is maintained by adjusting the screw-jack either forward or reverse dependent on the needs with a fixed support bracket that is attached to the screw-jack containing tube. Either a manually controlled jack handle or an electric motor that is reversible makes the adjustment of the screw-jack. With proper sensing devises the side plate pressures can be controlled remotely from a central location with an electrical control system. The ability to increase side pressure by use of the screw-jack allows the train to operate with much higher angles of inclination, approaching the angle of repose of the carried material.
Any gear reducer attached in line or perpendicular to the motor and ending with a vertical shaft for attachment with the drive tire will function for this application. To maintain simplicity the in-line system is preferred for ease of pressure adjustments and removal when required.
It is preferred to operate with a drive that is able to withstand substantial shock loads in cases where power failure occur while the train is in motion or when it enters a powerless drive station. It is also important to have a gear reducer that is able to function with high startup torque loads as discussed previously that may occur during loaded train start-up from dead stop. The preferred, but not limited to, drive is the SM cyclo concentric type gear drive from Sumitomo Heavy Industries. This system operates in a manner to meet the potential shock load and high torque startup requirements. Convention gear reducers will also work for this function, as the basic operation of the drive station is quite benign.
An important part of the drive system is the application of an inverter and controller system. Previous patented systems referenced did not have this type of system available, which has provided the most significant advancement in the light rail train concept. An inverter can control both frequency and voltages applied to A/C systems. The inverter and controller supplies line voltage and then distributes this voltage to opposing pairs of drive motors. The ability to control both frequency and voltage distribution is important in the synchronized operation of two drive motors and consistent speed of the opposing drive tires. The inverter system also can be used as a switch to control electric power and direction of rotation of the drive motors as well as a controlled rate of acceleration or de-acceleration.
An A/C inverter control synchronizes the rotational speed of both drives at a drive station. All the other drive stations are also set to operate at the desired rotational speed. By synchronizing all the drives, operational speed is controlled and smooth transfer of rotational thrust occurs from one station to the next, providing consistent train movement. All drive station controls can be set for local or remote operation, necessary to establish pressure requirements at each station. By use of the remote setting each A/C inverter can be controlled and monitored from a central control station through conventional conduit cables, fiber optic systems or radio signal control systems.
Controlled speed changes can be made from this remote station as well as controlled rates of acceleration or de-acceleration as may be required during loading or dump cycles. The inverter control system also provides the means of placing the drives in a operational position when a sensor on the track signals the arrival of a train, starts the drive to operational speed and shuts down the drive after the train clears that drive station. This continues around the track as the train makes a complete loop. By only operating when a train is present, energy usage is kept to a minimum.
A sensor attached to the track or at any location including the train itself can alert the station to start as the arrival of a train is acknowledged. The receipt of a signal initiates the start of the drive station so that it is running at its selected operating speed when the train actually arrives being driven by the preceding station. The train is always in contact with a drive station and is never allowed to roll free. Upon the passing of the last car through a station a shutdown sensor is actuated which shuts down that station, which is then in a dormant state awaiting the signal to start up again.
The use of the inverter control system also allows for a controlled rate of start up speed if the system is shut down for any purpose. If required, the inverter internal switch system can also allow the drive stations to operate in reverse, if backing up the train is required, in single train operations. The unique combination of both mechanical and electrical drive controls and motor control functions represents a very energy efficient system previously not available on earlier drive systems.
Energy is only used when the train is physically entering the drive station. This concept allows each drive station to operate independently of the other stations. It is important however, when a long loop is required with several trains operating that the inner-space between trains is consistent. If a station failure occurs or obstacle is encountered on the track all stations are shut down immediately with all the trains coming to a controlled stop. It is also required that each drive station be equipped with dynamic brakes to prevent train runaway on downhill runs and with positive locking brakes that are actuated in power off situations that can hold a train in place until the system can be returned to an operational status.
Information on a stations status as to operating temperature, percent of maximum torque load, rotational speed, and other status requirements can be transmitted through a multifunctional control cable and information cable, fiber optic line, radio transmission system linking all the drive stations with a central control station. Once programmed, the entire system will operate hands free with no direct operational control necessary.
The train as operated is totally powerless. In certain situations it is necessary to attach to the lead car a combination generator/battery pack to provide power for necessary safety features. A warning strobe light is required. In addition a small radar unit sends out a signal to advise of track obstacles, which would be coupled with a warning siren. If the obstacle persists an RF signal is then transmitted to the next station and the whole system is then shut down. Power from this generator/battery pack can also be used to provide a signal to the start sensor of a drive station to provide for redundancy in case of local station sensor failure.
In addition to the unique drive system the relationship of the drive plate to the car wheel is important. Locating the side drive plates symmetrical to the free rolling wheel gives access to a rail on both the top and bottom of the wheel. This allows operation of the train in an inverted position by using two sets of parallel rails on both sides of each wheel. With four rails the train is encapsulated because of the flanged wheel side movement limitations and minimal space between the parallel rails only slightly wider than the wheel diameters.
The rails can be bent to provide for a radius that would allow the cars to operate in an outside loop where both the top and bottom of the wheels are in near physical contact with the parallel rails. There is a point that during the loop the train weight is shifted to the top rail, which requires that the wheel will stop and start turning in the opposite direction. At the completion of an approximate 180° loop the cars would be inverted while functioning normally.
A flexible flap is attached near the leading edge of each car. This flap would overlap but not be connected to the trailing edge of the forward car. During normal transport the weight of the material on the car forces this flap against the round trough in the forward car, preventing leakage. Because of the material in the flap is flexible, the cars can twist and turn without losing sealing integrity. When a twist motion is required to rotate through 180 degrees the flap must be attached to the car several inches back of the lip of the car to allow for the displacement of the unaligned gap between cars with the flexible flap.
When operating in an outside loop the spacing between the individual car troughs opens up as the cars pivot around the clevis pin attachment. The rotary motion of the outside loop causes the lead car to drop away from the trailing car separating the flexible flap from the forward car. The flap then performs the function of a spout or chute as the material slides off the front of the car; it is projected over the car in front. Once the carried material slides off the car and spout formed by the flap, self-cleaning of the cars occurs. The combination of dumping speed and car flap trough extension allows for precise dumping without impact of the leading car with dumped material.
With the outside loop completed and the cars emptied, it is necessary to rotate the train back to the normal upright position or 180°. The rate of twist is dependent on selected car lengths, and distance available. The longer the distance the smoother the rotational transition with the non-flexible cars. During the twist phase four rails are still required until the car is in its normal operational position. For ease of installation, round steel stock can be substituted for the rail during this application. There is a period of time near the 90° stage of the twist phase that all of the car weight is hanging on the wheel flanges. This is a high wear environment. To compensate for this, a series of rollers are installed that physically contact the side plates and take the weight of the car rather than have the flanges in mechanical contact with the rails. Once the train is inverted after dumping the flexible flaps will again lay flat against the trough of the leading car.
Once emptied and inverted to the normal position the cars can be reloaded again be used to transport, dump, reload again and new material transported, with the cycle able to be repeated several times on the same track loop. For example, a single train can be used to haul coarse rock from a mine to a crushing system, dumped, then pick up processed product to transport to a loading site, dump and return to the plant to load waste to be returned to the mine site, dumped and the whole cycle then repeated. With the establishment of an integrated system addition trains can be added without any change to the operating components of the train system. The drive stations only recognize the arrival of a train.
The arrival of a second train to that station can be almost immediately after the first one leaves. Depending upon total loop distance one single train could be sufficient or up to one train per every other drive station could be used if haul capacity increases or distance cycle times requiring more trains are necessary. In the above multi-train type of operation the need for the redundant signals, controlled shutdown and power-off train lockdown is obvious.
From a consideration of
The drive wheels 12 are powered by the A/C electric motors 10 which are directly coupled to gear reducers 13. The A/C electric motor using U.S. power preferably operates on 480 volt three phase power. These motors run from 1750 to 1780 revolutions per minute (RPM). In order to achieve more torque the gear reducers lower the speed to a range of 50 to 125 RPM depending upon the application. The pressure of the wheels 12 on the car side drive plates 16, 17, 19, and 21 is adjusted by means of a hand crank 8. Each motor, reducer and drive tire 10, 13 and 12 is mounted vertically on a post, which allows the whole assembly to pivot around it. The drive unit is moved by the screw-jack using the hand crank forcing it to rotate toward the car side plate. The same function is preformed on the opposite side of the track so that the train is centralized with pressure equalized to provide traction.
The train is shown in
It is to be noted that each car has a durable and flexible sealing flap 18 attached near the front of each car and extends to cover the rear portion of the car directly in front. This flap effectively seals the gap between cars and also functions as an individual discharge spout for each car when the car is unloaded in an outside loop. This flap can be made of any suitable flexible material such as polyurethane, rubber, nylon, and the like.
The end and intermediate cars all have projections 24 on the lower front edge of the side drive plates 19 and 21. It is preferred to use semi-circular projections but any suitable shape can be used. The front car and all the intermediate cars all have a corresponding openings 26 in their in the lower rear side drive plates. This enables the train to be move in both vertical and horizontal plane.
The loading station for the train is of a conventional design as shown in
The train is pushed up the rail incline 2 to the double rail loop 41 supported by posts 42 with suitable footing such as concrete footing 40. As the train inverts, it projects outward its particular cargo and it accumulates into a pile 47. The transported cargo can then be transferred by standard material handling equipment for further operations or sold or stored.
