Field of the Invention

[0001 ] The present invention relates to equipment subject to abrasive wear. It is particularly applicable in apparatus used for mineral processing, such as crushers.

Background to the Invention

[0002] It is necessary to inspect the insides of chutes, crushers and the like in mining and mineral processing environments. Visual inspection can indicate the location of blockages, the degree of wear of sacrificial linings, and any damage which might exist on the inside of the chute. It is also necessary to access the inside of chutes for cleaning purposes.

[0003] It is preferable that visual inspection and basic cleaning is done without a 'shut-down' in operations. This means that it is desirable for visual inspection, and hosing out using high-pressure hoses to occur while particles - such as rocks - are falling through the chute, and potentially building up due to material 'hang up'.

[0004] In order to provide safety to an inspector or worker, it is known to provide an inspection grille or fence within the chute, covered by a door. When inspection is required, the door can be opened from the outside, and the inspector can look through the grille in order to conduct the inspection. Similarly, a worker can operate a high-pressure hose to clean within the chute while remaining outside. Typically, the grille is sized so that large rocks cannot pass through, and so that it is impossible for a worker to fall through or even trap a limb inside. Grilles may be formed from latticework, or may be a series of parallel bars.

[0005] Because the inside of the grille is open to the chute, it is subject to impact by rocks and other material passing through the chute. It will be appreciated that this causes abrasive wear on the grille, and that this wear occurs whether or not the door is open. Potentially, the grille may wear to a state of failure while the inspection door is closed, with a user not knowing this until the door is open. This puts the inspector or worker at significant risk of injury.

[0006] In order to alleviate this problem, it is desirable to provide a grille which is not subject to significant abrasive wear when the inspection door is shut.

[0007] The present invention has been created in light of this desire.

Summary of the Invention

[0008] According to one aspect of the present invention there is provided an opening for a material transfer passage, the opening having a first barrier including openings for visual inspection, and a second barrier which is arranged to selectively close against the first barrier, the second barrier including a plurality of abrasion-resistant projections, whereby the abrasion- resistant projections are arranged to project through the openings of the first barrier when the second barrier is in the closed position.

[0009] Preferably the first barrier is a grille.

[0010] Preferably the second barrier is a solid door. In one embodiment, the second barrier may be hinged to the opening and able to pivot about a vertical axis between the closed position and an open position.

[001 1 ] In an alternative embodiment the second barrier may be connected to the opening by an arm having an outer end and an inner end, the arm being hinged to the opening at its outer end and hinged to the second barrier at its inner end. In this embodiment the second barrier may be arranged to move in a translational manner relative to the first barrier.

[0012] The first barrier may be hinged to the opening, and able to pivot about a vertical axis between a closed position and an open position. [0013] The abrasion-resistant projections may each be releasably connected to the second barrier. In a preferred embodiment, each abrasion-resistant projection is independently bolted to the second barrier. In this way, a worn projection can be readily replaced.

[0014] Each abrasion-resistant projection may be directly connected to the second barrier. Alternatively, each abrasion-resistant projection may be spaced from the second barrier by a spacer. The spacer may be formed of a relatively light-weight material, such as a polymer.

[0015] The first barrier may have a latching means arranged to couple the first barrier to the opening when the first barrier is in its closed position.

[0016] The second barrier may have a latching means arranged to couple the second barrier to the opening when the second barrier is in its closed position.

[0017] The abrasion-resistant projections may be wear bars. [0018] The material transfer passage may be a chute. Brief Description of the Drawings

[0019] It will be convenient to further describe the invention with reference to preferred embodiments of the present invention. Other embodiments are possible, and consequently the particularity of the following discussion is not to be understood as superseding the generality of the preceding description of the invention. In the drawings:

[0020] Figure 1 is a perspective of an opening for a material transfer chute in accordance with the present invention, shown in a completely open configuration;

[0021 ] Figure 2 is a perspective of the opening of Figure 1 shown in a completely closed configuration, when viewed from the inside; [0022] Figure 3 is a front view the opening of Figure 1 shown with an outer door open;

[0023] Figure 4 is a perspective of the opening of Figure 1 shown in the completely closed configuration, when viewed from the outside;

[0024] Figure 5 is a front view of the opening of Figure 1 shown in the completely closed configuration, when viewed from the outside;

[0025] Figure 6 is a cross-section through line A-A of Figure 5;

[0026] Figure 7 is a perspective of an opening for a material transfer chute in accordance with a second embodiment of the present invention, shown from the inside in a completely open configuration;

[0027] Figure 8 is a perspective of the opening of Figure 7 shown from the outside in an open configuration;

[0028] Figure 9 is a perspective of the opening of Figure 7 shown in a completely closed configuration, when viewed from the inside;

[0029] Figure 10 is a perspective of the opening of Figure 7 shown in a completely closed configuration, when viewed from the outside;

[0030] Figure 1 1 is a front view of the opening of Figure 8 shown in the completely closed configuration, when viewed from the outside; and

[0031 ] Figure 12 is a cross-section through line A-A of Figure 1 1 .

Detailed Description of Preferred Embodiments

[0032] Referring to the first embodiment shown in Figures 1 to 6, Figure 1 shows a generally rectangular frame 10 defining an opening into a material transfer chute (not shown). The frame 10 has an internal face 12 oriented towards the interior of the chute, and an external face 14 oriented away from the chute. The frame 10 has a generally rectangular prismatic internal receiving portion 16 which extends between the internal face 12 and the external face 14.

[0033] Four hinges 18 are aligned along one longitudinal side of the external face 14. The hinges 18 combine to form a vertically aligned hinge axis.

[0034] A first barrier in the form of a grille 20 is hinged to the frame 10 by means of the hinges 18. The grille 20 has a series of vertical bars 22, perpendicular to a series of horizontal support bars 24. The grille 20 thus has an array of rectangular openings 26 in it. In the embodiment of the drawings the openings 26 form a 7 x 3 array, but it will be appreciated that other configurations are possible.

[0035] The grille 20 has latches 28 on an outer edge thereof, opposite the hinges 18. The latches 28 are arranged to engage with corresponding apertures 30 in the external face of the frame 10.

[0036] The grille 20 can be moved between an open position, such as that shown in Figure 1 , and a closed position such as that shown in Figures 2 to 6. When the grille 20 is in the open position, it is possible for a worker to move through the frame 10. When the grille 20 is in the closed position, it forms a barrier both to ingress of a worker and egress of rocks passing through the chute. It does, however, permit inspection of the interior of the chute, and the insertion of tools such as high-pressure water hoses for cleaning purposes.

[0037] The grille 20 can be maintained in the closed position through engagement of the latches 28 with the aperture 30.

[0038] A second barrier in the form of a door 40 is also hinged to the frame 10 by means of the hinges 18. The door 40 is located outside the grille 20, and can be moved independently of the grille 20.

[0039] The door 40 has a solid outer face 42. [0040] The door 40 can be moved between an open position, such as that shown in Figures 1 and 3, and a closed position such as that shown in Figures 2, 4 and 6. When the door 40 is in the closed position, the outer face 42 seals across the frame 10 and prevents a worker from seeing through the grille 20. It also prevents opening of the grille 20. When the door 40 is in the open position it permits inspection of the chute through the grille 20, and also permits opening of the grille 20.

[0041 ] The door 40 has an inner face 44. A plurality of abrasion-resistant protrusions in the form of wear bars 46 are fixed to the inner face 44. The wear bars 46 are arranged in an array corresponding to the openings 26 within the grille 20, with each wear bar 46 being sized so as to fit closely within a corresponding opening 26. The wear bars 46 have a depth greater than that of the grille bars 22.

[0042] The arrangement is such that when the door 40 is in the closed position, the wear bars 46 extend through the openings in the grille 20. The wear bars 46 are thus preferentially exposed to any rocks passing through the chute, and will wear in preference to the grille 20.

[0043] The wear bars 46 are fixed to the door 40 by means of bolts 48 passing through to the outer face 42 of the door 40. It will be appreciated that a single damaged wear bar 46 can be replaced by means of its bolted connection 48.

[0044] The door 40 has latches 50 on upper and lower edges thereof, away from the hinges 18. The latches 50 are arranged to engage with corresponding catches 52 in the external face of the frame 10.

[0045] The door 40 can be maintained in the closed position through engagement of the latches 50 with the catches 52.

[0046] It will be understood that during regular operation of the chute the grille 20 and the door 40 will remain in their closed positions. Material passing through the chute may impact against the wear bars 46, and cause damage and wear of these wear bars 46, but will not substantially impact the grille 20.

[0047] When inspection or cleaning of the chute is required, the door 40 can be opened. The grille 20 will remain in its closed position. This can be done with confidence that the grille 20 will remain structurally sound and undamaged, as it has been protected by the wear bars 46. When inspection has been completed the door 40 can be closed again, possibly with some replacement of wear bars 46 having been made.

[0048] When access to the chute is required (during a shutdown of operations), both door 40 and grille 20 can be opened.

[0049] Figures 7 to 12 show a second embodiment of the present invention, using the same general principles in a different configuration.

[0050] Figures 7 and 8 show a generally rectangular frame 1 10 defining an opening into a material transfer chute (not shown). The frame 1 10 has an internal face 1 12 oriented towards the interior of the chute, and an external face 1 14 oriented away from the chute. The frame 1 10 has a generally rectangular prismatic internal receiving portion 1 16 which extends between the internal face 1 12 and the external face 1 14.

[0051 ] Four hinges 1 18 are aligned along one longitudinal side of the external face 1 14. The hinges 1 18 combine to form a vertically aligned hinge axis. The hinges 1 18 include upper and lower hinges 1 18, and two intermediate hinges 1 19.

[0052] A first barrier in the form of a grille 120 is hinged to the frame 1 10 by means of the hinges 1 18. The grille 120 has a series of vertical bars 122. The grille 120 thus has an array of rectangular openings 126 in it. In the embodiment of the drawings the openings 126 form a 5 x 1 array, but it will be appreciated that other configurations are possible. [0053] The grille 120 can be moved between an open position, such as that shown in Figures 7 and 8, and a closed position such as that shown in Figures 9 and 10. When the grille 120 is in the open position, it is possible for a worker to move through the frame 1 10. When the grille 120 is in the closed position, it forms a barrier both to ingress of a worker and egress of rocks passing through the chute. It does, however, permit inspection of the interior of the chute, and the insertion of tools such as high-pressure water hoses for cleaning purposes

[0054] A second barrier in the form of a door 140 is also hinged to the frame 1 10 by means of an arm 160 connected to the intermediate hinges 1 19, as will be described below. The door 140 is located outside the grille 120, and can be moved independently of the grille 120.

[0055] The door 140 has a solid outer face 142.

[0056] The door 140 can be moved between an open position, such as that shown in Figures 7 and 8, and a closed position such as that shown in Figures 9 and 10. When the door 140 is in the closed position, the outer face 142 seals across the frame 1 10 and prevents a worker from seeing through the grille 120. It also prevents opening of the grille 120. When the door 140 is in the open position it permits inspection of the chute through the grille 120, and also permits opening of the grille 120.

[0057] The door 140 has an inner face 144. A plurality of abrasion-resistant protrusions in the form of wear bars 146 are fixed to the inner face 144. The wear bars 146 are arranged in an array corresponding to the openings 126 within the grille 120, with each wear bar 146 being sized so as to fit closely within a corresponding opening 126.

[0058] Each wear bar 146 is fixed to a corresponding spacer 147. Each spacer 147 is located between the inner face 144 of the door 140 and its associated wear bar 146. The spacers 147 have a cross sectional shape similar to that of the wear bars 146, but are made of a lighter-weight material, such as a polymer. The spacers 147 have a depth greater than that of the grille bars 122.

[0059] The arrangement is such that when the door 140 is in the closed position, the spacers 147 extend through the openings in the grille 120. The wear bars 146 are thus positioned well in advance of the grille 120, and are able to experience significant wear before the grille 120 is exposed to direct impact.

[0060] The wear bars 146 are fixed to the door 140 by means of bolts 148 passing through to the outer face 142 of the door 140 and the associated spacer 147. It will be appreciated that a single damaged wear bar 146 can be replaced by means of its bolted connection 148.

[0061 ] It will be appreciated that the wear bars 146 and thus the door 140 must move in a direction generally perpendicular to the vertical bars 122 in order for the wear bars to move within the openings 126. The door 140 achieves this by a dual hinge arrangement using the arm 160.

[0062] The arm 160 extends between an outer end 162 connected to the intermediate hinges 1 19 and an inner end 164 located around a midline of the door 140. The arm 160 is connected to the outer face 142 of the door 140 by a secondary hinge 166. The secondary hinge 166 is parallel to the hinge axis of the hinges 1 18.

[0063] The arm 160 is shaped to be spaced away from the outer face 142 of the door 140 between the intermediate hinges 1 19 and the secondary hinge 166.

[0064] The door 140 can thus be moved in a substantially translational manner, with the arm 160 pivoting relative to the intermediate hinges 1 19 in one angular direction and pivoting relative to the secondary hinge 166 in the opposite angular direction. The shape of the arm 160 allows sufficient translational movement of the door 140 for the wear bars 146 to clear the grille 120. Once the wear bars 146 have cleared the grille 120 the door 140 can be fully opened by pivoting around the intermediate hinges 1 19.

[0065] It is envisaged that the door 140 may include a restraining device to limit its rotation about the secondary hinge 166 once it is free from the grille 120.

[0066] It will be understood that during regular operation of the chute the grille 120 and the door 140 will remain in their closed positions. Material passing through the chute may impact against the wear bars 146, and cause damage and wear of these wear bars 146, but will not substantially impact the grille 120.

[0067] When inspection or cleaning of the chute is required, the door 140 can be opened, firstly by translational movement and then by rotation. The grille 120 will remain in its closed position. This can be done with confidence that the grille 120 will remain structurally sound and undamaged, as it has been protected by the wear bars 146. When inspection has been completed the door 140 can be closed again in a reverse operation, whereby it is pivoted about the intermediate hinges 1 19 into an ajar position, manipulated into a straight position by movement about the secondary hinge 166, and then pushed into the closed position allowing the hinges 1 19, 166 to work in opposition to each other.

[0068] When access to the chute is required (during a shutdown of operations), both door 140 and grille 120 can be opened.

[0069] Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.