DEFORMABLE/INhLATABLt WEAR LlNIrR

I hCHNlCAL I ILLD

I he inv ention i elates to a granular material deliv ery system, and more particularly to a chute having a defoimable inflatable w ear liner

BACKGROUND OP I HE INVLNl ION

In many industrial applications such as mines, etc , it is necessary 01 desirable to mov e appieciable quantities oi gianular mateπal from one location to anothei A conv eyoi usually a belt conv eyoi is employed to transport the granular mateπal such as bauxite oie, foi example Most ot such conv eyors have an input chute for dehv eiing the granular material to the conveyoi and a discharge chute ior discharging the granular mateπal at the output end of the com eyor In both cases, the chute often includes a weai hnei attached to the inner side of the chute wall The chute wall may be made ol steel plates and the weai liner may be made horn various mateπals such as ceiamic, stainless steel, iubber plastic, etc Such conventional chute w eai lineis mav piυv ide abiasiv e and impact resistance to the chute but are not successful in piev enting granulai matenal solids tiom building up in the transfer chutes of the matenal handling system The mateπal solids build-up can be particulaily sev ere duπng peiiods ol higher material moisture content Mateπal solids build-up can result in a complete blockage ol the mateπal flow through the chute and oi damage to the conveyoi belt il the matenal build-up is not prev ented oi iegulaily remov ed

I heieloie there is a need toi a method and apparatus to prev ent solids from building up in a gianulai matenal handling system duπng a material deliv ery operation

SUMMARY OF THE INVENTION

In accordance w ith one aspect of the present invention a method is provided for piev enting solids horn building up in a granular mateπal dehveiy passage dm ing a matenal dehv ei y operation the passage including at least a wall and a detoimable weai hnei provided on an inner suiface ot the wall for directing

granular materials sliding on the wear liner, the method comprising: a) introducing a pressuri/ed fluid into a space between the inner surface of the wall and the deformable wear liner to deform the wear liner, thereby causing a profile change of a cross-section of the granular material delivery passage.

In accordance with another aspect of the present invention there is provided a chute for a material handling system bearing granular materials, the chute comprising: at least one wall; a deformable wear liner having a wear-resistant surface, the deformable wear liner being attached to at least a section of the wall of the chute so as to allow pressuri/ed fluid to be introduced into a space between the deformable w ear liner and the wall in order to inflate the deformable wear liner; and means for introducing and discharging the pressurized fluid into and from the space between the deformable wear liner and the wall, respectively.

In accordance with a further aspect of the present invention, there is provided a granular material handling system which comprises a chute including a chute wall and a deformable w ear liner within the chute, the deformable wear liner being attached to an inner surface of a section of the chute wall so as to allow pressuri/ed air to be introduced into a space between the wear liner and the chute wall in order to inflate the wear liner; a source of pressurized air; a tube connected between the source of pressurized air and the space between the chute wall and the wear liner for delivery of pressurized air to inflate the wear liner; and a control apparatus for controllably inflating the wear liner and discharging pressuri/ed air from the space between the chute wall and the wear liner, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present invention will become apparent from the following detailed description, taken in combination with the appended drawings, in which:

Figure 1 is a schematic side ele\ ational view of a granular material handling system including a typical belt conveyor and a transfer chute;

Figuic 2 is a eioss-sectional view taken along line 2-2, showing a cross- section of the transtei chute

1 igure 3 is a top plane view of a poly ceramic sheet used to iorm a chute wear liner in the gianulai material handling system illustiated in Figure 1 ,

1 igure 4 is a partial cross-sectional \ iew of the transtei chute of Figure 1 illustrating an original state of the poly ceiamic sheet of Figure 3 attached to a section of a chute wall as a chute w ear liner

1 igui e S is a similai v iew to that ol 1 igure 4 showing an inflated state of the poly ceramic sheet oi Hgute 3 attached to the section of the chute wall as the chute w ear liner

Figure 6 is a top plane v iew of a multiple segmented wear lmer, and

Figuie 7 is partial cioss-sectional v iew of the transfei chute of Figure 1 , show ing a deformable inflatable v\ eai liner made oi the multiple segmented liner of 1 igui e 6

It will be noted that throughout the appended draw ings, like features are identified by like reference numerals

DETAILED DESCRIP FlON OP 1 HL EMBODIMEN I S

1 igure 1 illustiates a gianular material handling system 10 in which a belt conv eyoi 12 has an input end (not show n) and a dischaige end 14 Pulley 16 is prov ided at the iespectn e input and discharge ends I he pulley 16 at either of the input or dischaige ends may be dm en and the iotational diiection of the pulley 16 is indicated by arrow A \ conv eyoi belt 18 including a material-bearing run and a return run (respective top and bottom runs), engages the pulley 16 at the both input and dischaige ends The belt 18 mov es in the direction indicated by the aπow B The length ol the conv eyoi 12 is deteimmed by the requnements of the application

A tiansfer chute 20 is prov ided at the discharge end 14 of the belt conveyoi 12 to tiansfer the gianulai mateπal (not indicated) such as bauxite solids

delivered by the belt conveyor 12 and discharged into the transfer chute 20, to a storage pile or other destination. The direction of movement of the granular material from the belt conveyor 12 into the transfer chute 20 is indicated by arrow C.

In Figures 1 and 2, the transfer chute 20 is shown as having an open cross-section or a pipe-type closed cross-section (not shown), defining at least one chute wall. λs one example of a transfer chute, chute 20 includes a bottom chute wall 22 and side chute walls 24, 26 at opposite sides thereof, respectively, forming a channel to direct a tlow of the granular material sliding under the force of gravity along the chute 20. The chute w alls 22, 24 and 26 may be made of any suitable material, for example, metal plates such as steel plates. A deformable/inflatable wear liner 28 is provided within the chute 20 in order to protect the metal walls from wearing, abrasion and corrosion. The deformable/inflatable wear liner 28 is attached to at least a section of at least one of the chute walls. It is understood that the liner could be prov ided only on selected areas of inner surfaces of the chute walls or alternativ ely, it could be prov ided on the entire inner surfaces of the chute walls 22, 24 and 26. As an example of the present inv ention illustrated in Figures 1 and 2, the liner 28 is attached to the chute wall 22 of the chute 20.

The deformable/inflatable wear liner 28 can be attached along its periphery to an inner surface of a section of the chute wall 22 so as to allow pressurized air to be introduced into a chamber or space (see Fig. 5) between the deformable/inflatable wear liner 28 and the chute wall 22 in order to inflate the wear liner 28. The inflated state of the deformable/inflatable wear liner 28 as shown by the broken lines in Figure 2. changes the profile of the cross-section of the channel defined by the chute walls 22, 24, 26. The deformable/inflatable wear liner 28 offers a wear-resistant surface at a side exposed to the granular material. The attachment of the deformable/inflatable wear liner 28 to an inner surface of a section of the chute wall 22 may be achieved by a layer of adhesive 30 applied along the peripheral edges of the wear liner 28 between the wear liner 28 and the chute wall 22.

Pressurized air may be obtained from a pressurized air source 32 which ma) be a pressurized air tank or a blow er low pressure air pump, or the like, and is

deliv ered through a tube 34 which is connected at the other end thereof to an opening 36 defined in the chute wall 22. A switch device such as a control valve 38 may be installed in the tube 24 to control the introduction and termination of pressurized air flow into the space between the deformable/intlatable wear liner 28 and the chute wall 22. The control valve 38 may optionally also have a function of controllably discharging the pressuri/ed air from the space between the deformable/inflatable wear liner 28 and the chute wall 22 when the control valve 38 is turned to a position for terminating pressuri/ed air flow from the pressuri/ed air source 32 to the chute 20. Otherwise, an additional discharging valve may be provided (not shown) with the tube 34. If the pressurized air source is a blower/low pressure pump, the control valve 38 may also be replaced by a switch for controlling the operation of the blower/low pressure pump. A maximum pressure safety valve 40 may be provided to ensure that the pressure of the pressurized air introduced to the place between the deformable'inflatable wear liner 28 and the chute wall 22 is not over a predetermined level. The maximum pressure safety v alve 40 may be incorporated to the tube 34 or mounted directly to another opening 39 defined in the chute wall 22.

In Figures 1 -5, the deformable/inflatable wear liner 28 includes at least one flexible plate, such as an elastomer polymer substrate 42 with a plurality of side- by-side wear-resistant tiles, such as ceramic tiles 44, embedded into one side of substrate 42. In accordance with one embodiment of the present invention, one of these materials commercially available for such applications is a "poly ceramic sheet", for example a "Concord Poly Ceramic Sheet TM", which is a sheet made of elastomeric polymer provided with ceramic tiles on one side thereof. The tiles 44 could also be glued or otherwise securely attached to the substrate 42. The poly ceramic sheet is highly flexible and is suitable to be deformed for inflation in this application. One or more poly ceramic sheets may be used to form the deformable/inflatable wear liner 28, and may be bonded or otherwise suitably attached to the underlying section of the chute wall 22 by using, for example, standard rubber adhesives as indicated by numeral 30 in Figure 2. The ceramic tiles 44 on the elastomeric sheet or substrate 42 function as the wear-resistant surface of the wear liner 28 while the flexibility of the elastomer sheet provides the deformable/inflatable feature of the wear liner 28 so as to allow creation of a liner

surface which can be disturbed by inflation and deflation on a regular basis to prevent solids from building up within the transfer chute 20.

In operation, pressuπ/ed air flow may be introduced from the pressurized air source 22 through the tube 34 into the space between the deformable/inflatable wear liner 28 and the chute wall 22 such that the deformable/ inflatable wear liner 28 is inflated as shown in f igure 5 and by the broken line in Figure 2 The arrow indicated b> numeial 35 in f iguie 5 is used to illustrate the pressuπ/ed air flow to inflate the wear liner 28 I he wear liner 28 in the inflated state may be further disturbed/deformed by the moving loads of the granular materials to which the deformable/inflatable wear liner is exposed to support same within the chute 20

After a period of time the introduction of the pressuπ/ed air flow is terminated and the pressuπ/ed air is allow ed to discharge from the space between the deformable inflatable wear liner 28 in the inflated state and the chute wall 22, by, for example operating the contiol \ al\ e 38 λs a result of discharging the pressuπ/ed air, the deformable/ inflatable v\ ear linei 28 is allowed to return to the original state, as shown in Figures 1 and 4, causing a profile recovery of the cross-section of the channel defined by the chute walls 22, 24 and 26, as shown in Figure 2. During periods of time when the deformable/inflatable wear liner 28 extends on the underlying chute wall 22 without being deformed/inflated, the deformable/inflatable wear liner 28 Junctions similarly to a conv entional chute liner

l he steps of inflating and discharging pressuπ/ed air from the deformable inflatable w ear liner 28 may be repeated periodically. According to one embodiment of the present inv ention, the operation can be conducted with air-on (inflation) for a relatively short period of time, for example twenty seconds and then air-off (aftei discharging pressuπ/ed air) ibi a relativ ely long period of time, for example 1 hour, on an alternating basis at a low operating air pressure, for example 3 psi T he maximum pressure safety v alv e 40 w ill be adjusted accordingly According to anothei example, the system is operated under a 7 second inflation/3 minutes deflation cycle I he deflation time can vary depending on the material sticking to the

tiles, the quicker the material stick, the shorter the time between inflation and deflation.

Figures 1 -2 and 6-7 illustrate another embodiment in which one or more multiple segmented poly ceramic sheets may be used as the defbrmable/inflatable wear liner which is indicated as 28' in Figures 6 and 7. The multiple segmented deformable, inflatable w ear liner 28' includes a plurality of segments 46 (6 segments shown in Figures 6), each segment being similar to a single poly ceramic sheet forming the deformable/inflatable wear liner 28 as shown in Figures 3-5, and will not be redundantly described herein.

The multiple segmented deformable/inflatable wear liner 28' may be attached to any section or an entire area of the inner surface of the chute walls 22, 24 and 26. For convenience of description, the multiple segmented deformable/inflatable wear liner 28' is illustrated as being attached to a section of the chute wall 22 of the transfer chute 20, similar to the prev iously described embodiment. The multiple segmented deformable/inflatable wear liner 28' is attached to the section of chute wall 22 by using an adhesive (not shown) such as the standard rubber adhesives between the liner 28' and the chute wall 22 along the peripheral edges of each segment such that each segment may be inflatable independently from others, as shown in Figure 7, in which two air chambers are formed behind two respective segments 46 of the wear liner 28' at opposite sides thereof by charging pressurized air (indicated by arrow 35) into the space between the corresponding segments 46 and the chute wall 22, through respective openings 36a and 36c in the chute wall 22 while the middle segment 46 of the wear liner 28' remains in the original state (not inflated or deformed) because no pressurized air is charged into the space between this segment 46 and the chute wall 22 through the opening 36b in the chute wall 22.

In operation of a multiple segmented deformable/inflatable wear liner 28' each of the segments 46 of the deformable inflatable wear liner 28' may be alternately air-charged and air-discharged to achieve the independent inflation of the respective segments of the deformableinflatable wear liner 28'. This may be

achieved by a pressurized air system having a plurality of llow-controllable tubes 34 leading to multiple openings such as 36a-36c. The periodic air-charging and air- discharging operations of the respective segments 46 of the multiple segmented wear liner 28' may be conducted independently, for example, on a rotating basis. Alternativ ely, the periodic air-charging and air-discharging operations for the respective segments of the multiple segmented wear liner 28' may be conducted simultaneously. In the latter case, a single tube 34 with a single switch device may be used to connect a multiple-way fluid connector which is in turn connected to respective openings such as 36a-36c in the chute wall 22.

According to one embodiment, the system is arranged in two separate sections inflated alternately. This embodiment is particularly useful for use in a stacker chute, which is one possible application of the present invention. In this particular case, the two sections are the lower chute and the baffle. The discharge of the chute is relatively small and tends to block very easily. So for this reason, it is advantageous to inflate the lower chute section to remove any build up, and then inflate the upper section including the baffle. This minimizes the chances of excess build up blocking the chute. By so alternating the inflation between separate sections, it is also possible to operate more liners from a smaller compressor. The alternating of the inflation between separate inflatable sections or /ones also provides for the use of different inflatable wear plate si/es. By connecting one inflatable wear plate size to one \ al\ e at a giv en inflation time, a given ov erall pressure is obtained. Then, by connecting a different inflatable wear plate size to another valve at a different time interval, a different overall pressure is obtained. Different inflatable wear plate sizes require different pressures to inflate them and as such if only one air pressure source is used, the different sizes wear plates must be inflated at different time intervals to prov ide for proper operation of the system.

Alternativ e to the above-described embodiments, the deformable inflatable w ear liner may be made from a flexible sheet having two layers to form an inflatable pocket defined therebetween.

T he above-descπption is meant to be exemplary only, and one skilled in the art will recogni/e that changes may be made to the embodiments described without depaiting from the scope of the inv ention disclosed P or example, the underlying section of the chute wall to support the deiormable inflatable w ear liner is described and illustiated as a flat steel plate, but the defoimable inflatable wear lmer may be attached to any section 01 an entne area oi the innei surface of othei types of chutes which are not flat and are made of any suitable material known and unknown in the industiy The pressuπ/ed an systems desciibed in the above-embodiments are used as an example to illustrate the operation of the deformable inflatable wear liners Various piessun/ed an equipment and systems may be used for the same purpose Bauxite solids are used as an example of the gianulai materials which the transfei chute beais and dehveis Howevei, it is understood that the deformable inflatable w eai hneis can be used in any similai granular mateπal handling sy stem foi handling a vanety oi gianular matenal such as gianulai coal, aggiegate, oi other mining mateπal w hich is within a given granule si/e range Still other modifications which fall within the scope of the invention will be apparent to those skilled in the ait in light of a lewew of this disclosure, and such modifications are intended to fall within the appended claims