Belt transportation system

Abstract

A conveyor belt (10) of closed-path type comprising a plurality of transport plates (50), defining a transport surface for the material in a forward run of the conveyor belt itself, which plates are arranged in sequence along a longitudinal transport direction (L), wherein each plate bears a first (55) and a second (56) longitudinal end portion thereat, in said forward run, it is respectively superimposed on an adjacent plate arranged upstream of the sequence with respect to the longitudinal transport direction and placed under an adjacent plate arranged downstream in such sequence, or vice versa; and an annular structure (51) for connecting said plates being arranged, in said forward run, below said plates, wherein at least one of said plates, at said first or second longitudinal portion of superimposing or placing under an adjacent plate, has a cross section with thickness (s) decreased with respect to a remaining portion of the plate itself.

Claims

1. A conveyor belt capable of the dry handling bulk material even at high temperature, such as DRI (Direct Reduced Iron) outgoing from reducing oven/reactor, which conveyor belt is supported on supporting rollers and is of closed-path type and comprising: transport plates optionally made of metal, which transport plates define a transport surface for the bulk material in a forward run of the conveyor belt, which transport plates are arranged in sequence along a transport longitudinal direction, wherein each transport plate bears a first and a second longitudinal end portion that, in said forward run, is respectively superimposed on an adjacent transport plate arranged upstream of the sequence with respect to the transport longitudinal direction and placed under an adjacent transport plate arranged downstream in such sequence, or vice versa; and an annular structure for connecting said transport plates such annular structure being net-like shaped made of metal, which annular structure is arranged, in said forward run, below said transport plates, which annular structure acts as motion transmission organ and connects two drums arranged at longitudinal ends of the conveyor belt, wherein at least one of said transport plates has, at a lower surface of said first longitudinal portion superimposed to an adjacent plate or at an upper surface of said second longitudinal portion placed under an adjacent plate, a cross section with thickness decreased with respect to a remaining portion of the transport plate, in such a way that step-like profiles at the contact between the conveyor belt and the supporting rollers are eliminated or reduced and that mechanical interference between said lower surface and an end edge of the adjacent transport plate during rotation on the two drums is eliminated, wherein said connection between each transport plate and said annular structure is obtained in a plate region distinct from said first and second longitudinal portion of superimposing/placing under adjacent plates, wherein each one of said transport plates, in said first or second longitudinal portion, has a planar development along said transport longitudinal direction with a tapered section, or chamfer, with thickness decreasing towards the end portion of the transport plate, wherein said chamfer has a chamfer angle greater than or equal to a maximum rotation angle of each transport plate around a drum, and wherein said chamfer has a longitudinal length equal to a superimposing/placing-under run of the transport plates.

2. The conveyor belt of claim 1, wherein each one of said transport plates has said second longitudinal portion placed under an adjacent transport plate, such adjacent transport plate arranged upstream of the sequence with respect to the longitudinal transport direction, and wherein said section with decreased thickness with respect to a remaining portion of the transport plate is obtained at such second longitudinal portion.

3. The conveyor belt of claim 1, wherein said decreased thickness is comprised in a range of about 2-6 mm.

4. The conveyor belt of claim 1, configured to be arranged with said longitudinal transport direction tilted with respect to the horizontal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The figures of the enclosed drawings will be referred to, wherein FIGS. 1A to 5A have been already mentioned above with reference to the known art and wherein, in particular:

(2) FIGS. 1A to 5A have been already mentioned above with reference to the known art;

(3) FIG. 6 relates to a first preferred embodiment of a transport device according to the invention, by showing a cross section view thereof;

(4) FIG. 6A shows a top plan view of a portion of a conveyor belt of the device of FIG. 6;

(5) FIG. 7 relates to a second preferred embodiment of a transport device according to the invention, by showing a cross section view thereof;

(6) FIG. 8A relates to a preferred embodiment of a conveyor belt according to the invention, preferably a part of the device of FIG. 6 or 7, by showing a side view thereof;

(7) FIG. 8B shows a longitudinal section view of the forward run of the conveyor belt of FIG. 8A;

(8) FIG. 8C shows an enlarged detail of FIG. 8B;

(9) FIG. 8D shows a longitudinal section view of a backward run of the conveyor belt of FIG. 8A;

(10) FIG. 9 relates to an additional preferred embodiment of a transport device according to the invention, by showing a side view thereof;

(11) FIGS. 9A and 9B show each one a respective enlarged detail of FIG. 9;

(12) FIG. 10 shows a schematic geometrical representation of the rotation angle of plates of the transport device of FIG. 9 around a drum of the same device.

(13) The sizes, and in particular the thicknesses and the angles, represented in the above-mentioned figures, are to be meant by pure way of example and they are not necessarily shown in proportion.

Detailed Description of Preferred Embodiments

(14) Several embodiments and variants of the invention will be described hereinafter, and this by referring to the above-mentioned Figures.

(15) Generally, analogous components are designated in the different figures with the same numeral reference.

(16) In the following detailed description, additional embodiments and variants with respect to embodiments and variants already treated in the description itself will be illustrated limitedly to the differences with respect to what already illustrated.

(17) Furthermore, the different embodiments and variants described hereinafter can be used in combination, when compatible.

(18) By referring to FIGS. 6 and 6A, a transport device according to a first preferred embodiment of the present invention is designated as a whole with 1.

(19) The transport device 1 is suitable for the dry transport of high flow rates of bulk material or lump size material, such as for example DRI (Direct Reduced Iron) from a reducing oven or bottom ash outgoing from a combustion chamber. In a specific application, the device 1 is indeed of the type apt to be arranged below reducing ovens/reactors for the production of DRI or the boiler of a plant for producing energy from fossil fuel.

(20) The device 1 mainly comprises: a conveyor belt, designated as a whole with 10, a container, casing or frame 2 within which the conveyor belt 10 is received, and supporting means 3 of a backward run of the conveyor belt 10.

(21) Each one of the above-mentioned components will be now described in greater detail.

(22) The conveyor belt 10 is of closed-path type, that is annular, and, upon use, it has a forward run 12 and a backward run 13. For better clarify, FIG. 6 shows a transport direction, or longitudinal direction L, which is indeed the forwarding direction of the conveyor belt in the forward run and in the backward run, with opposite directions in the two runs. Two mutually orthogonal directions, and also perpendicular to the direction L, are further defined, that is a cross direction T corresponding to the width of the conveyor 10 and an elevation direction E. In the representation of FIG. 6, the direction L is orthogonal to the sheet and the two directions T and E lie on the sheet.

(23) The development of the conveyor belt 10 in the two forward and backward runs 12 and 13 can be considered substantially planar according to the directions L and T.

(24) The two main runs 12 and 13 are connected by two curved connecting runs at the winding around the driving and driven drums, similarly to what already illustrated with reference to the known art.

(25) Upon use, at the forward run 12 a transport region 14 is defined, delimited on the lower side by a transport surface 11 extending in direction L and T and laterally by two containment borders, or bulkheads 21 of the transported material. The latter develop in elevation from the transport surface 11 along the direction E as far as its own end margin 22 and also extend in direction L.

(26) The casing 2, preferably of sealing type, also houses the components responsible for the motion of the conveyor belt 10, in particular the above-mentioned one or more driving and driven drums. Since such components are of type known on itself one will not further dwell upon the description thereof.

(27) The casing 2 further houses cross supporting rollers 24 of the conveyor 10 in the forward run 12 or elements equivalent thereto. In particular, such rollers 24 can be arranged with regular pitch along the longitudinal extension of the conveyor 10. Typically, the rollers 24 are free to rotate around their own axis by means of interposition of roller bearings, or equivalent means, assembled on the container 2.

(28) In the backward run 13, the conveyor belt 10, downstream of the discharge of the transported material, is supported by means of the above-illustrated means 3. Such means, in the present example, comprises a plurality of continuous transversal rollers 35, free to rotate (idle) around their own axis by means of roller bearings arranged at the two ends and outside the section of the conveyor belt. Said rollers are parallel to the width of the conveyor itself, that is the direction T, and only one is visible in FIG. 6. Each roller 35 preferably supports two wear elements 31 whereupon the end margins 22 of the containment borders 21 are rested.

(29) Based upon a different embodiment shown in FIG. 7, the supporting means, herein designated with 3, provides the use of revolving (idle) elements, in particular rollers, 36 cantilevered assembled at the flanks of the container 2. In particular, roller bearings are provided assembled on the flanks of the container 2 and supporting indeed the revolving elements 36 and respective cross uprights, or hubs, 35. Even in this case, upon the elements 36 the end margins 22 of the containment borders 21 are rested. In this way, interferences of the means for supporting the backward run of the conveyor belt with possible cleaning pendula or buckets 25 of the container bottom 2. Such configuration with pendula is described in WO 2009/138949, which is meant to be incorporated herein by means of this reference.

(30) In other components thereof, the configuration of FIG. 7 is analogous to that of FIG. 6.

(31) The structure of the conveyor belt 10, based upon a particularly preferred embodiment of the invention, is shown in greater detail in FIGS. 8A, 8B, 8C and 8D.

(32) The transport surface 11 is defined by a longitudinal sequence of transport plates 50, typically made of metal and partially superimposed one with respect to the other one at respective end longitudinal portions. In particular, by considering the advance direction V along the transport direction L, each plate 50 is superimposed on the plate preceding it (that is downstream with respect to the direction V) and placed under the plate following it (that is upstream with respect to the direction V).

(33) More specifically, on each plate a first and a second longitudinal end portion, respectively 55 and 56, can be detected. At such portions 55 and 56 the plate 50, in the forward run 12 of conveyor belt 10, is respectively superimposed on an adjacent plate arranged upstream of the sequence with respect to the transport direction L and placed under an adjacent plate arranged downstream in such sequence.

(34) According the invention, each plate 50, at the second longitudinal portion 56 of placing under an adjacent plate, has a section (according to the plane defined by the directions E and L) with thickness s decreased with respect to a remaining portion of the plate itself. In this way, in the superimposition region the overall thickness of a step of the contact surface between conveyor belt 10 and transport rollers 24 results to be reduced.

(35) Preferably, such decreased, or reduced, thickness is obtained by means of a tapered section profile, with thickness decreasing in the direction opposite to the advance one, that is decreasing towards the longitudinal end (upstream) of the plate 50.

(36) The not reduced thickness of each plate 50 can be comprised in a range of about 4-10 mm. Said decreased thickness can be comprised in a range of about 2-6 mm.

(37) The above-mentioned thickness decrease can be obtained, for example, by milling or by means of other processes such as moulding, hot forging or melting.

(38) Embodiment variants can provide that the thickness decrease is obtained not on all plates but on alternated plates, and then in a selected number of plates both at the first and at the second portion 55 and 56. In particular, at the portion 55 the thickness decrease can implement an undercut, or recess or receipt, for the adjacent plate, however obtaining the decrease in height of the step in the contact surface between conveyor and supporting elements 24.

(39) Each plate 50 bears the already mentioned side borders 21 with function of containing the material transported on the surface 11. Thanks to the superimposition of adjacent plates, even the respective side borders are partially superimposed in longitudinal direction. Such superimposition of borders increases the overall contact surface of the conveyor belt 10 with the revolving elements 31 or 36 of the supporting means 3, 3, by improving the overall mechanical stability of the support and, in general, of the device.

(40) The plates 50 are fastened to a metallic net 51, shaped like a ring, by means of screws 53, rivets or equivalent means. In embodiment variants, the net-like structure can be replaced by a chain or by a different annular structure. Such connection between plates and annular structure is preferably obtained in a region of each plate distinct from the superimposition portions 55 and 56.

(41) Similarly to the known art, the wire net 51 can act as organ for transmitting the motion, by connecting, as already mentioned, two drums with adequate diameter arranged at the longitudinal ends of the conveyor belt 10. As already said, one of such drums can be moved by means of electric motor connected to the shaft thereof, the other one can be idle and induced to rotate around its own axis thanks to the contact by friction of the metallic net 51 put in tension by a suitable tensioning system, the latter known on itself and thus not further described.

(42) Thanks to the above-mentioned selective decrease in thickness of the plates, the net-like belt, or an annular structure equivalent thereto, substantially rests in planar way upon the plates themselves and then on supporting rollers 24. In this way, the traction force exerted by the connecting screws 53 does not deform the position of the net-like belt and it does not affect the linearity thereof. Therefore, the vibrations mentioned with reference to the known art are absent, or however strongly reduced.

(43) FIGS. 9, 9A and 9B relate to an additional preferred embodiment of a structure of conveyor belt according the invention, which will be described mainly only in relation to the differences with respect to the previous embodiments. In particular, FIGS. 9A and 9B show an enlarged detail of the superimposition of the plates, herein designated each one with 500, substantially at the same points F and E already considered with reference to the known art (FIGS. 1E and 1F). Such figures highlight then the mutual positions of two subsequent plates both in the substantially rectilinear transport run 12, and during the winding on the drums, in the specific case on the idler drum 202.

(44) According to the invention, each plate 500, at a terminal longitudinal portion 560 of placing under an adjacent plate (the latter designated with 500), has a section (according to the plane defined by the directions E and L already mentioned above) with decreased thickness s with respect to a remaining portion of the plate itself.

(45) Even in this case, such decreased, or reduced, thickness is obtained by means of a tapered section profile with decreasing thickness. In particular, the terminal portion 560 bears a chamfer, with taper tilting in direction L designated with a.

(46) Even this thickness decrease can be obtained, for example, by milling or by means of other processes like moulding, hot forging or fusion.

(47) The geometry of superimposing between the plates, and in particular the mutual position in the area of plate placed under the adjacent one, is so as to prevent the detach between such plates in both running directions during the rotation on the drum, as highlighted in FIG. 9A and better explained hereinafter.

(48) As already said, when the belt joins the plates on the traction an idler drums 201 and 202, each plate 500, 500 performs a rotation equal to an angle around an ideal axis parallel to the transport cross surface in direction T and passing through the connecting point thereof to the metallic net or other supporting element. The angle is schematically illustrated in FIG. 10. During the rotation the mutual position of each plate changes.

(49) In the configuration of FIGS. 9, 9A and 9B the surface of the upper plate 500 in the rotation thereof around the drum 202 with reversed running direction Rdoes not meet an obstacle consisting in the end cross edge P of the plate 500 placed thereunder. Similarly, in the nominal running direction V the end cross edge P of the placed-under plate 500, in the rotation thereof around the drum 201, does not meet an obstacle on the lower surface of the superimposed plate 500.

(50) As said, such absence of mechanical interference is obtained by providing a chamfer on the placed-under end 560 of each plate, with a chamfer angle greater than or equal to the maximum rotation angle covered by each plate on the drum.

(51) Still in a preferred configuration, the length of the chamfer, or however of the portion with reduced thickness, in direction L performed on each plate has a length equal or substantially equal to the superimposition run of the plates. Preferably, the contact position of the superimposed plate coincides with the upper beginning, or leading line, of the chamfer of the placed-under plate.

(52) In this way the placed-under plate portion wholly receives the end of the superimposed plate by making the profiles to match and by guaranteeing a continuous contact and with increased surface extension of the adjacent plates, both in the transport position and in the winding on the drum position.

(53) The same advantage is obtained in case of conveyor belt arranged tilted, that is with not horizontal transport direction L.

(54) Furthermore, such adhesion between the plates is obtained at the winding on both drums, independently from the running direction.

(55) It will be appreciated that the invention can be applied even with types of belt conveyors having side prolongations, or appendixes, of the transport surface as those shown for example in FIGS. 2A and 2B and described with relation to the known art.

(56) Based upon preferred embodiments, the belt of the invention is suitable to receive flow rates of material in the order of 2000 m.sup.3/h for cross widths of the conveyor of 2000 mm and height of the containment side borders of 500 mm, in particular with speeds of 0.5 m/s.

(57) Furthermore, still based upon preferred embodiments, the invention can allow an increase in the belt speed up to even 5-8 times the above-mentioned traditional speed, thus with speeds in a range of about 0.5-0.8 m/s.

(58) Moreover, still based upon preferred embodiments, the invention allows a reliable operation of the conveyor both in case of reversal running and in case of high tilting of transport.

(59) The present invention has been sofar described with reference to preferred embodiments. It is to be meant that other embodiments belonging to the same inventive core may exist, as defined by the protective scope of the herebelow reported claims.