Abstract
A conveyor belt driven by linear motors distributed along the belt, rather than at the head thereof. These linear electric motors or of the induction type with a short primary (5) having two action sides and a long secondary (2) made of plates (8; 12) of conducting material, such as aluminium or copper. The secondary (2) plates (8; 12) are vertically fixed in the central portion of the rubber belt (1) or metal plates (22). The invention is equipped with split central load rollers (14) and return drums (3) with grooves (11) accommodating the passage of the secondary plates (8; 12) during the belt (1) path.
Claims
1. A conveyor for granular material and wherein operates in transporting ranulated articles from mining or other sources, the conveyor comprising: n a rubber or metallic belt (1); a linear induction electric motor to drive the rubber or metallic belt; the linear induction motor an active double-sided primary (5) with long and sectioned secondary (2) of overlapping plates (8) or trapezoidal plates (12) installed in a central and an internal portion of the conveyor (1) transport loop, a metal structure (16) supporting the rollers (14; 15 and 18); in turn, central load rollers (14) and side load rollers (15) support the belt (1); the belt (1) in turn follows its closed-loop path, looping around return drums (3) located at the ends of the conveyor; the conveyor having biparite central load rollers (14) and return drums (3) with grooves (11) accommodating a passage of the secondary plates (8; 12) during a belt (1) path.
2. (canceled)
3. The conveyor according to claim 1, wherein the conveyor belt d is sectioned with conductive plates (8, 12) made of aluminum, copper, or alloys.
4. The conveyor according to claim 1, wherein the conveyor operates through distributed motorization along a linear length.
5. The conveyor according to claim 1, wherein the long and sectioned secondary (2) is positioned vertically as a keel installed, removably with mechanical fasteners or permanently through of adhesives, welding or vulcanization, on an internal surface of a closed circuit formed by the conveyor.
6. (canceled)
7. The conveyor according to claim 1, wherein the conveyor includes a plurality of linear electric motors to dynamically distributing operating load between motor units.
8. The conveyor according to claim 1, further including linear induction motors to regenerate energy on sloped terrain or in moments of speed reduction with the loaded conveyor.
9. The conveyor according to claim 1, further including a plurality of linear induction motor units with active braking capacity through the double-sided primary drive to guarantee a wide range of operation including keeping the treadmill stationary under load.
10. (canceled)
11. The conveyor according to claim 1, wherein the conveyor operates vertically.
12. The conveyor according to claim 1, further including a metal feeder having a belt made of metal plates and secondary plates fixed directly to the metal plate.
13. (canceled)
14. The conveyor according to claim 1, further including centralizing guide elements (6) on the secondary (2) in relation to the primary (5) gap, and also centralizing the bell (1) on a transport bed.
Description
BRIEF DESCRIPTION OF THE FIGURES
[0056] The entire system can be better understood through the following detailed description, in line with the attached figures, where:
[0057] FIG. 1 shows a partially exploded view of the transportation system in which it is possible to observe the rubber belt, the secondary plates of the motor, the return drum at one end of the conveyor, the roller support structure of the conveyor belt, the representation of the primary units of the linear motor distributed along the length of the conveyor. This figure illustrates only one end of the equipment; the other end of the conveyor is symmetrical and can be seen in FIG. 7;
[0058] FIG. 2a shows a side view of the linear motor displaying: the centralizing devices of the secondary plates, the plate fixations, the overlapping type secondary plates;
[0059] FIG. 2b shows the lateral free space between the active faces of the primary and the secondary plates, commonly referred to as the air gap.
[0060] FIG. 3a shows the arrangement of the sectioned secondary plates, of the overlapping plate type, in the curved section on the return drum in a side view, where: is shown the overlap section of plates both in the straight and in the curved return;
[0061] FIG. 3b is the groove on the return drum to allow the accommodation and operation of the secondary plates during the return curve.
[0062] FIG. 4a shows the side view detail of the plates of the secondary version with overlapping plates;
[0063] FIG. 4b shows a respective front view;
[0064] FIG. 4c, the perspective view;
[0065] FIG. 5a represents a side view of the second geometry of secondary plates that can be used in this belt conveyor. The geometry of this plate is trapezoidal to allow accommodation in the return curvature performed on the return drum. The fixations are the same as the overlapping plates illustrated in FIG. 2;
[0066] FIG. 5b shows the free space continues to be present;
[0067] FIG. 6a shows the side view of the curved section for the trapezoidal geometry of the secondary plates where is shown the gap between plates formed by successive trapezoidal geometries. In the curve is also the gap, so that the lateral edges of the trapezoidal plates become parallel;
[0068] FIG. 6b shows the groove or slots on the return drum to allow the accommodation of the secondary plates;
[0069] FIG. 7a shows the detail of the version of the secondary with trapezoidal plates;
[0070] FIG. 7b shows a front view of FIG. 7a;
[0071] FIG. 7c shows a perspective view of FIG. 7a;
[0072] FIG. 8a illustrates the side view of the conveyor belt with the sectioned secondary plates fixed vertically facing the underside of the belt as a keel;
[0073] FIG. 8b shows a front view of FIG. 8a;
[0074] FIG. 8c shows a perspective view of FIG. 8a;
[0075] FIG. 9a shows a side view of the conveyor with the complete transport loop for a better understanding of the system. This figure shows the arrangement of several primary units of the motor installed on the upper and lower branches of the transport belt.
[0076] FIG. 9b shows perspective view of the conveyor of FIG. 9a;
[0077] FIG. 10 represents the roller support structure showing the split central roller, the inclined side rollers, the roller support structure in structural steel, and the roller bearings.
[0078] FIG. 11 shows another type of linear conveyor, in a side view called a metallic conveyor/feeder, which is driven by the double-sided linear motor as in FIG. 1. Where it is also possible to observe: the secondary of the linear motor, the sprocket wheel guiding the link chain, the head shafts that are coupled to the sprocket wheels and rotate with the movement of the conveyor.
[0079] FIG. 12 shows another view of this metallic feeder (apron feeder) where it is possible to observe that several sets of linear motors can be installed in parallel, in the available space within the transport loop formed by the metal belt.
[0080] FIG. 13 shows another type of linear conveyor that uses distributed motorization. In this configuration, the conveyor operates in the vertical position and is called a bucket conveyor. In this illustration, the vertical segment of the bucket elevator is shown, where along with the loading compartment called a bucket, the secondary of the motor positioned inside the transport loop formed by the flat rubber belt, and the primary units of the linear motor.
DETAILED DESCRIPTION OF THE INVENTION
[0081] The distribution of the load of the material transported on conveyors naturally leads to distributed propulsion, especially in long conveyors.
[0082] Linear motors, therefore, offer greater control over the transported load, eliminating operational inefficiencies when compared to conventional concentrated propulsion at the head of the conveyor.
[0083] Referring to these figures, it is possible to observe, in FIG. 1 and FIG. 9b, the general arrangement of the main equipment that composes the conveyor belt, in this version, with distributed traction along its length through various units of primary linear motors that are summed up to reach the power required to perform the work on this conveyor.
[0084] In the linear motor used, the primary (5) of the induction electric motor remains static and integral to the conveyor structure, while the secondary (2) of the motor moves relative to this primary (5).
[0085] The primary part is the active equipment that receives electrical power to activate its windings. The motor used is of the active dual-sided type where these sides correspond to two sets of iron cores and various windings that are positioned against each other, forming a central gap through which the secondary plates (2) must pass for induced current generation.
[0086] Electromagnetic forces are generated by the primary (5) through the control of electric current and frequency in the windings of its coils. Control and drive are performed by frequency inverters.
[0087] The generated force is transmitted without contact from the primary to the secondary plates, maintaining a distance between the faces of both called the air gap.
[0088] The segmented plate secondary (8; 12) is guided in the gap by the electromagnetic forces generated in the primary (5) and thus pulls the belt (1) that is free to translate supported on rollers (14, 15, and 18) and drums (3).
[0089] The load of material to be transported is deposited in a distributed manner on the upper surface of the belt (1) and is carried by the movement generated in the linear motor.
[0090] The linear motor also serves to center the belt on top of the conveyor roller structure. Sometimes, granular loads may be deposited asymmetrically on the belt, and conventional conveyors, this leads to misalignment between the belt and the rollers (14, 15, 18) and drums (3). With the linear motor, this issue tends to be reduced due to the presence of guide elements (6) and the fact that the force applied to the secondary (2) has a restoring property of central positioning. If any plate (8,9) is closer to one of the faces of the primary, it should experience a repulsive force, bringing it toward the middle of the gap formed by the faces of the primary.
[0091] The conveyors (1), usually made of rubber for applications in granular transport, remains supported on top of load rollers (14; 15, and 18) and performs a closed cycle, looping around return drums (3).
[0092] In FIG. 2, the version of the linear motor with overlapping plates is depicted. The overlapping plates (8), made of conductive material such as aluminum or copper, form a continuous train with some overlap (10). This overlapping of the plate faces (FIG. 4a) allows the continuity of the secondary, enabling the full utilization of the plate area that passes through the middle of the internal faces of the primary motor. This fact also allows the continuous secondary (2) to follow the curvature of the return drums. These drums must have a compatible diameter for the dimensions of the plates (8, 12) to avoid jamming due to deformation generated by the contact between the plates during pivoting on the curved surface of this drum (3).
[0093] Devices called centralizing guides (6) must be installed at the ends of the primary (5) of the motor. They can be of the sliding or rolling type and have the role of guiding the plates (8, 12) to the central position between the active faces of the linear motor primary (5). Thus, an equidistant air gap (9) is maintained between the faces and the motor plates (8, 12). This positioning is important to prevent contact and consequent damage to both parts of the motor. Additionally, the air gap (9) establishes a direct connection with the efficiency and torque of the motor.
[0094] In FIG. 2, the fixings (7) of the plates (8, 12) on the rubber conveyor (1) can also be observed. These parts are attached to the secondary (2) plates (8, 12) and are screwed or riveted into the rubber of the belt to allow for working traction.
[0095] The return drum (3) can be seen in FIGS. 3a and 3b, as well as its equatorial groove (11) that permeates the entire cylindrical surface and allows for the accommodation of the motor's secondary (2) plates (8, 12) during the return curve of the belt cycle.
[0096] FIG. 5a reveals the second type of segmented secondary (2), the type of plates (12) with trapezoidal geometry. These plates of electrically conductive material are mounted on the rubber conveyor (1) belt in a train-like vertical position one after the other so that there is no overlap of plates (12) in this version of the secondary (2). This fact allows for a shorter distance between the faces of the linear motor primary (5) but causes some efficiency loss due to the existence of empty spaces (13) between one plate and its successor. These details can be better visualized in FIG. 7a.
[0097] FIG. 8 shows a view of the rubber belt (1) with the secondary plates (8, 12) installed on its lower portion. The fixation should be done either temporarily through screws or rivets attaching the fixator (7) to the rubber (1) or permanently through vulcanization or some adhesive. The possibility of removing the plates is important from a maintenance standpoint, and the possibility of permanent fixation is interesting from an operational safety standpoint. These measures should be considered by the engineers.
[0098] FIG. 9a shows a side view of the rubber conveyor belt used for transporting granular materials from mining equipped with distributed linear motorization.
[0099] FIG. 10 shows the most important parts of the linear motor-driven conveyor equipment, where both a primary motor unit (5) and a section of the secondary (2) can be seen, as well as the metallic support structure (16) for rollers, its central load rollers (14), and the lateral rollers (15). These load rollers (14, 15) support the central weight of the transported load above the rubber belt. In this equipment, the load rollers need to be bipartite to allow the passage of the secondary blades in the central branch between rollers. The distance between these central rollers must be minimal to allow the passage of the plates (8, 12) without compromising the load support by the rubber belt (1).
[0100] FIG. 11 illustrates a side view of the drive system of a metal feeder/conveyor, the only peculiarity of this equipment being that instead of a rubber belt (1), metal plates are closing the transport loop circuit. These metal plates (22) carry the volume of granular material from mining, with their ends fixed to the side link chain (21). The chain (21) operates on both sides of the metal conveyor and engages (20) with the return sprockets.
[0101] In conventional metal conveyors, traction is achieved through a motor gearbox assembly coupled to the shaft of the return sprockets (20). This invention proposes that this equipment use the same linear motor mentioned in the previous figures like FIG. 2a and FIG. 5a and no longer use a motor gearbox assembly at its end.
[0102] FIG. 12 shows an isometric view, where 3 sets of linear motors aligned parallel to the longitudinal axis of the equipment are visualized. Since this metal feeder operates with very high workloads and has a greater width, it allows for distributed motorization both in its length and width.
[0103] FIG. 13 illustrates a vertical conveyor or bucket elevator as it is commercially called. The peculiarity of this equipment is to operate in the vertical position and have buckets (23) made of rubber fixed on the external surface of the transport loop, which serve to lift the load from one level to another, being filled with granular material. This invention also proposes distributed motorization in this type of equipment, dispensing with the rotary motorization installed in the head drum. The situation of this equipment is quite similar to that of FIG. 1 with the difference that in the bucket elevator, the rubber belt (24) is flat and oriented vertically. In this conveyor, the central rollers (14) and the return drums (3) must also have grooves (11) or be bipartite to allow the passage of the secondary (2) plates (8, 12).
[0104] All the described equipment: horizontal rubber belt conveyor, metal feeder, and bucket elevator can operate with both types of secondary: overlapping plate (8) type and trapezoidal (12) plate type.
[0105] The invention was developed to simplify the operation and maintenance of conveyor belts since current equipment requires very high mechanical tensioning. Such tensions cause stretching in rubber, friction between moving parts, wear of bearing elements, and energy inefficiencies.
[0106] The proposed distributed linear drive increases the reliability and availability of the equipment since, in case of a failure in any of the motors, there is no need to stop the operation for maintenance, as the load can be redistributed to the other operating linear motor units.
