WO2012051651A1

WO2012051651A1 - Blockage detection

Info

Publication number: WO2012051651A1
Application number: PCT/AU2011/001328
Authority: WO
Inventors: Jeremy Michael Hoslin; Ronald Bell; Peter Bourke
Original assignee: Wear Applications & Management Services Pty Ltd
Priority date: 2010-10-19
Filing date: 2011-10-19
Publication date: 2012-04-26

Abstract

A blockage detection unit, blockage detection system, material transfer system and method are disclosed for detecting a blockage of a chute. In one aspect, the blockage detection unit is configured to: obtain a first signal indicative of a first load value from a first unit for detecting a load of material being transferred upon at least a portion of a first material transport assembly toward an inlet of the chute; obtain a second signal indicative of a second load value from a second unit for detecting a load of material deposited onto at least a portion of the second material transport assembly from an outlet of the chute; and use the first load value and the second load value to detect a blockage when the load material entering the chute is substantially discrepant to the load of the material exiting the chute.

Description

BLOCKAGE DETECTION

Background of the Invention

The present invention relates to detecting a blockage in a material transfer system.

Description of the Prior Art

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that the prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

It is a common problem that when material, such as raw materials (i.e. iron ore, coal, etc), is transferred using a material transfer system including a chute, the material may block the material transfer system. This can occur for a number of reasons such as the specific properties of the material being transferred, the speed of the material flow in the chute, as well as a range of other factors. In any event, in order for the material transfer system to run effectively it is generally recommended to attempt to detect, as soon as possible, when such a blockage has occurred such that some action can be performed to rectify the blockage.

One common monitoring system currently employed includes the use of a microwave beam unit which is located under a head pulley, wherein the microwave beam unit generates a microwave beam which projects across the chute. When the chute is full and the beam is broken, the conveyor belt is shut down. The disadvantage to this type of monitoring system is that dust or rogue rock can break the microwave beam thereby leading to a false detection of a chute blockage.

Another monitoring system includes the use of tilt switches. As the chute is tilted due to a reduced amount of material exiting the chute, the tilt switch may sense an angular tilt which satisfies an angular threshold. The disadvantage to this type of monitoring system is that the tilt sensors can be subject to collision with material in the chute which can lead to false positive detections of a chute blockage due to angular realignment of the tilt sensor or malfunction of the tilt sensor. Therefore there is a need to overcome or at least alleviate one or more of the above- mentioned problems, or provides a commercial alternative.

Summary

In a first aspect there is provided a blockage detection unit for use in a blockage detection system of a chute, wherein the blockage detection unit is configured to:

obtain a first signal indicative of a first load value from a first unit for detecting a load of material being transferred upon at least a portion of a first material transport assembly toward an inlet of the chute;

obtain a second signal indicative of a second load value from a second unit for detecting a load of material deposited onto at least a portion of the second material transport assembly from an outlet of the chute; and

use the first load value and the second load value to detect a blockage when the load material entering the chute is substantially discrepant to the load of the material exiting the chute.

In one embodiment, the blockage detection unit includes a processor associated with memory.

In another embodiment, the blockage detection unit is configured to use the second load value which temporally offset by a temporal offset value relative to the first load value to determine if the load material entering the chute is substantially discrepant to the load of the material exiting the chute.

In one form, the temporal offset value is stored in the memory.

In another form, the blockage detection unit is configured to dynamically generate and store the temporal offset value based upon at least one of the first load value and the second load value.

In an optional embodiment, the blockage detection unit is configured to:

obtain, from a first velocity sensor, a first velocity which the load of material is being transferred upon the first material transport assembly;

obtain, from a second velocity sensor, a second, velocity which the load of material is being transferred upon the first material transport assembly; and

use the first and second velocities to detect the if the load material entering the chute is substantially discrepant to the load of the material exiting the chute.

In another optional embodiment, the blockage detection unit is configured to:

adjust the first load value according to the first velocity to determine a first comparable value;

adjust the second load value according to the second velocity to determine second comparable value; and

use the first comparable value and the second comparable value to determine if the load material entering the chute is substantially discrepant to the load of the material exiting the chute.

In an optional form, the blockage detection unit is configured to determine a differential value between the first comparable value and the second comparable value, wherein the blockage is detected in the event that the comparable value exceeds a comparison tolerance value.

In another optional form, the comparison tolerance value is stored in the memory.

Optionally, the blockage detection unit is configured to dynamically generate and store the comparison tolerance value in the memory based upon at least one of the first load value and the second load value. In one embodiment, in the event that the blockage detection unit detects a blockage, the blockage detection unit interrupts operation of the first material transport assembly.

In another embodiment, in the event that the blockage detection unit detects a blockage, the blockage detection unit interrupts operation of the second material transport assembly.

In one form, in the event that the blockage detection unit detects a blockage, the blockage detection unit actuates an alarm. In a second aspect there is provided a blockage detection system including:

a first unit for generating a first signal indicative of a load of material being transferred upon at least a portion of a first material transport assembly toward an inlet of the chute;

a second unit for generating a second signal indicative of a load of material deposited onto at least a portion of the second material transport assembly from an outlet of the chute; and

a blockage detection unit configured to:

obtain the first signal indicative of a first load value;

obtain a second signal indicative of a second load value; and use the first load value and the second load value to detect a blockage when the load material entering the chute is substantially discrepant to the load of the material exiting the chute.

In one form, the blockage detection unit includes a processor associated with memory.

In another form, the blockage detection unit is configured to use the second load value which temporally offset by a temporal offset value relative to the first load value to determine if the load material entering the chute is substantially discrepant to the load of the material exiting the chute.

In one embodiment, the temporal offset value is stored in the memory. In another embodiment, the blockage detection unit is configured to dynamically generate and store the temporal offset value based upon at least one of the first load value and the second load value.

'

In an optional form:

the first unit is a first load sensor for detecting a load of material being transferred upon a portion of a first material transport assembly toward an inlet of the chute;

the second unit is a second load sensor for detecting a load of material deposited onto a portion of the second material transport assembly from an outlet of the chute.

In another optional form, the blockage detection system includes:

a first velocity sensor for sensing a first velocity which the load of material is being transferred upon the first material transport assembly; and

a second velocity sensor for sensing a second velocity which the load of material is being transferred upon the second material transport assembly;

wherein the blockage detection unit is configured to:

obtain* from a first velocity sensor, a first velocity which the load of material is being transferred upon the first material transport assembly;

obtain, from a second velocity sensor, a second velocity which the load of material is being transferred upon the first material transport assembly; and

use the first and second velocities to detect the if the load material entering the chute is substantially discrepant to the load of the material exiting the chute. In one embodiment, the blockage detection unit is configured to:

use the first comparable value and the second comparable value to determine if the load material entering the chute is substantially discrepant to the. load of the material exiting the chute.

In another embodiment, the blockage detection unit is configured to determine a differential value between the first comparable value and the second comparable value, wherein the blockage is detected in the event that the comparable value exceeds a comparison tolerance value.

In one form, the comparison tolerance value is stored in the memory. In another form, the blockage detection unit is configured to dynamically generate and store the comparison tolerance value in the memory based upon at least one of the first load value and the second load value.

In an optional embodiment, the blockage detection system includes:

an alarm;

wherein the blockage detection unit is configured to actuate the alarm upon detecting a blockage.

In another optional embodiment, in the event that the blockage detection unit detects a blockage, the blockage detection unit interrupts operation of the first material transport assembly.

In an optional form, in the event that the blockage detection unit detects a blockage, the blockage detection unit interrupts operation of the second material transport assembly.

In a third aspect there is provided a material transfer system including:

a chute having an inlet and an outlet;

a first transfer assembly for transferring material toward the inlet of the chute; a second transfer assembly for receiving material exiting the outlet of the chute; and

a blockage detection system according to embodiments of the second aspect. In a fourth aspect there is provided a method of detecting a blockage in a chute, wherein the method includes, in a blockage detection unit:

obtaining a first signal indicative of a first load value from a first unit for detecting a load of material being transferred upon at least a portion of a first material transport assembly toward an inlet of the chute;

obtaining a second signal indicative of a second load value from a second unit for detecting a load of material deposited onto at least a portion of the second material transport assembly from an outlet of the chute; and

using the first load value and the second load value to detect a blockage when the load material entering the chute is substantially discrepant to the load of the material exiting the chute.

In another embodiment, the method includes the blockage detection unit using the second load value which is temporally offset by a temporal offset value relative to the first load value to determine if the load material entering the chute is substantially discrepant to the load of the material exiting the chute.

In one form, the method includes storing and retrieving the temporal offset value from the memory. In another form, the method includes the blockage detection unit dynamically generating and storing the temporal offset value based upon at least one of the first load value and the second load value.

In an optional embodiment, the method includes the blockage detection unit:

obtaining, from a first velocity sensor, a first velocity which the load of material is being transferred upon the first material transport assembly; T U2011/001328

- 8 - obtaining, from a second velocity sensor, a second velocity which the load of material is being transferred upon the first material transport assembly; and

using the first and second velocities to detect the if the load material entering the chute is substantially discrepant to the load of the material exiting the chute.

In another optional embodiment, the method includes the blockage detection unit:

adjusting the first load value according to the first velocity to determine a first comparable value;

adjusting the second load value according to the second velocity to determine second comparable value; and

using the first comparable value and the second comparable value to determine if the load material entering the chute is substantially discrepant to the load of the material exiting the chute. In an optional form, the method includes the blockage detection unit determining a differential value between the first comparable value and the second comparable value, wherein the blockage is detected in the event that the comparable value exceeds a comparison tolerance value. In another optional form, the method includes storing and retrieving the comparison tolerance value from the memory.

Optionally, the method includes the blockage detection, unit dynamically generating and storing the comparison tolerance value in the memory based upon at least one of the first load value and the second load value.

In one embodiment, in the event that the blockage detection unit detects a blockage, the method includes the blockage detection unit interrupting operation of the first material transport assembly.

In another embodiment, in the event that the blockage detection unit detects a blockage, U2011/001328

- 9 - the method includes, the blockage detection unit interrupting operation of the second material transport assembly.

In one form, in the event that the blockage detection unit detects a blockage, the method includes the blockage detection unit actuating an alarm.

Other embodiments will be described throughout the description of the example embodiments. Brief Description of the Drawings

Embodiments will now be described with reference to the accompanying drawings, in which: -

Figure 1A illustrates a block diagram representing an example of material transfer system including a blockage detection system, wherein the material transfer system includes no blockage;

Figure IB illustrates a block diagram representing the material transfer system and blockage detection system of Figure 1A, wherein the material transfer system includes no blockage;

Figure 2 illustrates a block diagram representing an example of a comparator unit;

Figure 3 illustrates a flow chart representing a method of detecting a blockage in the chute of the material transfer system of Figure 1 ;

Figure 4 illustrates a schematic of an example of a material transfer system including a blockage detection system; Figure 5A illustrates a magnified view of section A of Figure 4 of the schematic of the material transfer system; U2011/001328

- 10 -

Figure 5B illustrates a magnified view of section B of Figure 4 of the schematic of the material transfer system; and Figure 6 illustrates a flowchart representing a further example of a method of detecting a blockage in the chute of a material transfer system.

Detailed Description of the Preferred Embodiments

The following modes, given by way of example only, are described in order to provide a more precise understanding of the subject matter of a preferred embodiment or embodiments. In the figures, incorporated to illustrate features of an example embodiment, like reference numerals are used to identify like parts throughout the figures.

Referring to Figure 1A and IB there is shown a material transfer system 10. The material transfer system in Figure 1A includes no blockage, whereas the material transfer system in Figure IB includes the presence of a blockage. The material transfer system 10 includes a chute 20, a first and second transfer assembly 30, 40, and a blockage detection system 71 including a first and second unit 50, 60 provided in the form of a first and second load sensor, and a blockage detection unit 70.

The chute 20 includes an inlet 21 and an outlet 22 for receiving and transferring material 80. The first transfer assembly 30 transfers material 80 into the inlet 21 of the chute 20, and the second transfer assembly 40 receives material 80 exiting the outlet 22 of the chute 20. The first load sensor 50 is configured to detect a load 81 of material being transferred upon at least a portion of a first material transport assembly 30 toward the inlet 21 of the chute 20. Similarly, the second load sensor 60 is configured to detect a load 82 of material deposited onto at least a portion of the second material transport assembly 40 from the outlet 22 of the chute 20. The blockage detection unit 70 is configured to obtain a first signal indicative of a first load value from the first load sensor 50. The blockage detection unit 70 is configured to P T/AU2011/001328

- 1 1 - obtain a second signal indicative of a second load value from the second load sensor 60. The blockage detection unit 70 is further configured to use the first load value and the second load value to detect a blockage when the load of the material entering the chute is substantially discrepant to the load of the material exiting the chute.

It will be appreciated that the blockage detection unit 70 may simply compare the first load value to the second load value. However, other forms of processing or manipulation can be performed using the first load value and the second load value to detect the presence of a blockage.

When a blockage is detected by the blockage detection unit 70, the blockage detection system 70 may perform a detection activity. The detection activity can include raising an alarm (audio and/or visual), and/or deactivating the operation of the first material transfer assembly 30 and optionally the second material transfer assembly 40 such that further material is restricted from entering the inlet 21 of the chute 20. In one form, the alarm may be raised via a control unit in electrical communication with the blockage detection unit 70, wherein an operator is able to review the alarm and indicate, via an input device of the control unit, whether the first material transfer assembly 30 is to be shutdown. However, in another option, the shut down of the first material transfer assembly 30 may be performed automatically upon detection of a blockage in the chute 20, wherein the reactivation of the first material transfer assembly 30 and optionally the second material transfer assembly 40, if it has be deactivated, can be selected via an input device of the control unit.

The blockage detection unit 70 may take the form of any electrical unit that is able to obtain the first signal indicative of a first load value, the second signal indicative of a second load value, and perform a comparison between the first load value and the second load value to determine if a blockage has occurred. The blockage detection unit 70 can take the form of a processing system that is in electrical communication with the first and second load sensors 50, 60. However, other electrical units such as an electrical circuit including a comparator circuit can alternatively be utilised. The blockage detection unit 70 may be configured to interpret or convert the first and second signals into the respective 2011/001328

- 12 - first and second load values such that a comparison can be performed.

An example of a suitable processing system 200 for use as the blockage detection unit 70 of the blocked detection system 71 is illustrated in Figure 2. The processing system 200 is formed from a processor 210 coupled to a memory 21 1 , an input/output device 212 such as a keyboard and display or the like and an external interface 213 via a bus 214. The external interface 213 is in communication with the first and second load sensors 50, 60. The external interface is preferably also in communication with a first and second drive assembly 35, 45 of the first and second material transfer assemblies 30, 40 respectively. The processor 210 executes software stored in the memory 21 1 to monitor the first and second load values to determine if a blockage in the chute 20 has occurred. Control commands may be supplied via a user, with operational parameters, or other information being displayed via the I/O device 212. As shown in Figure 2, the external interface 213 can optionally also be in communication with a first velocity sensor 410 and a second velocity sensor 420 for sensing the velocity of material being transferred upon the first and second material transfer assembly 30, 40 respectively. The use of the first and second velocity sensors 410, 420 will be discussed in more detail in relation to Figures 4 and 6.

It would be appreciated that a wide range of processing systems 200 may be used such as a standard generalised computer system, a programmable logic controller (PLC) or the like, or alternatively, in the form of a custom processing unit such as a Field Programmable Gate Array (FPGA).

Referring to Figure 3 there is shown a flowchart representing an example of a method of detecting a blockage using the material transfer system 10 of Figures 1 and 2.

In particular, at step 310 the method 300 includes obtaining the first signal indicative of the first load value from the first load sensor 50 for detecting the load of material being transferred upon a portion of a first material transport assembly 30 toward the inlet 21 of U2011/001328

- 13 - the chute 20.

At step 320, the method 300 includes obtaining the second signal indicative of the second load value from the second load sensor 60 for detecting the load of material deposited onto a portion of the second material transport assembly 40 from the outlet 22 of the chute 20,

At step 330, the method 300 includes determining, using the first and second load values, if the load of the material 81 entering the chute 20 is substantially discrepant to the load of the material 82 exiting the chute 20. In the event that there is no substantial discrepancy, the method 300 proceeds back to step 310. However, in the event that there is a substantial discrepancy, a blockage has been detected as indicated by step 340 in the flowchart of Figure 3.

Referring to Figure 4 there is shown a schematic of a material transfer system 10 including the blockage detection system 71. In particular, the first material transfer assembly 30 is a first conveyor belt assembly and the second material transfer assembly 40 is a second conveyor belt assembly, wherein the chute 20 transfers material 80 which enters via the first material transfer assembly 30 to the second material transfer assembly 40, Each conveyor belt assembly 30, 40 includes a plurality of idlers 510, 520 for causing the respective belts to travel.

As shown in Figure 5 A, at least one of the idlers 510 of the first material transfer assembly 30 is operably coupled to the first load sensor 50. Specifically, the first load sensor 50 in the form of a first load cell is located under the respective idler 510. When material is transferred by the belt over the idler. 510, the first load sensor 50 measures the load of the material which is passing over the portion of the belt located above the respective idler 510. As will be appreciated, the first load value is indicative of the portion of the material that is present above the idler 510 operably coupled to the first load sensor 50. A similar arrangement is also utilised for the second material transfer assembly 40, as shown in Figure 5B, wherein at least one of the idlers 520 of the second material transfer assembly 40 is operably coupled to the second load sensor 60. The one or more idlers 510, 520 of the first and second material transfer assembly 30, 40 may also be utilised to determine the velocity which the material is being transferred thereover respectively. In one form, a first and second velocity sensor 410, 420, as shown in Figure 2, may be associated with one or more of the idlers 510, 520 of each material transfer assembly 30, 40 to determine the velocity which the material is being transferred thereover. However, in some instances, a control unit of the first and/or second transfer assemblies 30, 40 may include some form of velocity measurement which can be utilised by the blockage detection unit 70 for detecting a blockage.

Referring to Figure 6 there is illustrated a flowchart representing a further example of a method 600 of detecting a blockage in a material transfer system 10.

In particular, at step 605, the method 600 includes the blockage detection unit 70 initialising particular settings of the blockage detection system 71. This can include setting a temporal offset value and a comparison tolerance value. The temporal offset value is the time period which the specific portion of material, which is sensed by the first load sensor 50, is expected to travel and be sensed by the second load sensor 60. This temporal offset can be determined based on historical records or can be set manually by an operator based on inspection of the operation of the material transfer system 10. The blockage detection unit 70 can dynamically adjust the temporal offset value during operation of the system 10 based upon recent sensed load values, wherein more recent recordings can be more heavily weighted than older recordings. The comparison tolerance value is indicative of an acceptable tolerance between the difference between first load value and the second load value adjusted according to the velocities which the material is being transferred. Specifically, it will be appreciated that it is unlikely that the exact same load of material that enters the chute.10 also exits the chute 10 due to various imperfections of the material transfer system 10. However, an acceptable tolerance can be utilised to determine if the comparison falls outside the acceptable tolerance thereby indicating the detection of a blockage in the chute 20. The comparison U2011/001328

- 15 - tolerance value may be defined as a percentage value, range or specific load value. Again, the comparison tolerance value can be determined based. on historical records or can be set manually by an operator based on inspection of the operation of the material transfer system 10. Additionally or alternative, the blockage detection unit 70 can adjust the comparison tolerance value dynamically during the operation of the system 10.

The blockage detection unit 70 may include a number of operational profiles specific for the type material being transferred. In particular, an operator can interact with a control unit of the blockage detection unit 10 to indicate the type of material that is being transferred. Based on this input, pre-defined settings which set the temporal offset and comparison tolerance value can be utilised during the operation of the blockage detection system 71.

In another variation, the blockage detection unit 70 may obtain one or more material property values indicative of one or more properties of the material 80 being transferred. The blockage detection unit 70 can then use the one or more material property values to retrieve or calculate appropriate initialisation values, such as the temporal offset value and the comparison tolerance value. In one form, the blockage detection unit 70 may receive such material property values from one or more sensors, such as one or more moisture sensors (not shown). The load of the material being transferred may also influence the temporal offset and comparison tolerance values, thus the load sensed by the first load sensor 50 and/or the second load sensor 60 can be used to dynamically adjust the temporal offset and comparison tolerance value during the operation of the system 10. At step 610, the method 600 includes obtaining the first load value at a first point in time. In particular, the first load sensor 50 senses the load which is present upon the one or more idlers 510 associated with the first load sensor 50. The first load sensor 50 transfers the first signal indicative of the first load value to the blockage detection unit 70 for interpreting the first load value. The first load sensor 50 may periodically sense the first load value thereby providing the blockage detection unit 70 a series of discrete load values, however a continuous analogue first signal may also provided to the blockage detection unit 70;

At step 615, the method 600 includes obtaining the first velocity value. In particular, the first velocity sensor 410 in the form of a first velocity sensor may sense the number of revolutions of the one or more idlers 510 of the first material transfer assembly 50 and transfer a first velocity signal indicative of the first velocity value to the blockage detection unit 70 for interpretation.

At step 620, the method 600 includes the blockage detection unit 70 adjusting the first load value according to the first velocity value. For example, in the everit that the first load value is 50Kg arid the first velocity value is 2m/s, the blockage detection unit 70 can divide the first load value by the first velocity value to obtain a first comparable value of 25.

At step 625, the method 600 includes the blockage detection unit 70 obtaining a second load value at a second point in time, wherein the second point in time is delayed relative to the first point in time by the temporal offset. The manner in which the second load value is obtained is similarly performed compared to the step of obtaining the first load value.

At step 630, the method 600 includes the blockage detection unit 70 obtaining a second velocity value at the second point in time. Again, the manner in which the second load value is obtained is similarly performed compared to the step of obtaining the first velocity value.

At step 635, the method 600 includes the blockage detection unit 70 adjusting the second load value according to the second velocity value. This step is performed similarly to step 620. It will be appreciated that in the event that the first material transfer assembly 30 is transferring material at a greater velocity than the second material transfer assembly 40, the first and second load values cannot be compared without adjustment. Thus, by using the first and second load values which are adjusted according to the respective velocities of the first and second material transfer assemblies 30, 40, first and second comparable values are obtained which can be used for determining if a blockage has occurred. At step 640, the method includes the blockage detection system subtracting the second comparable value from the first comparable value to determine a difference value. This step allows for the blockage detection system to determine if more material is entering the chute than exiting the chute.

At step 645, the method 600 includes determining if the difference value exceeds the comparison tolerance value. In particular, in the event that the difference value exceeds the comparison tolerance value, a blockage has been detected, wherein the method proceeds to step 650. In the event that the difference value fails to exceed the comparison tolerance value, no blockage is detected and the method proceeds back to step 605 to continue repeating steps 610 onwards.

At step 650, the method 600 includes the blockage detection unit ceasing operation of at -least the transfer of material by the first material transfer assembly 30 and optionally the transfer of material by the second material transfer assembly 40. In particular, the blockage detection unit 70 may be in communication with the first and second drive assemblies 35, 45, shown in Figure 3, for the first and second material transfer assemblies 30, 40, wherein the blockage detection unit 70 can cease the operation of the first drive assembly 30 and optionally the second drive assembly 40.

Preferably, once the blockage has been detected, some form of alarm can be raised as discussed previously. A visual alarm may be presented via an output device of the blockage detection system 71. Additionally, or alternatively, an audible alarm is raised indicating the detection of a blockage. A message may also be transferred by the blockage detection system 71 to one or more recipients via a message communication means, wherein the blockage detection system may be in the form of SMS, e-mail, pager message, or the like, such that an operator located remotely can be notified of the blockage that has been detected.

The blockage detection unit 70 can also record the sensed values in an operation log file such that the operation of the material transfer system 10 can be reviewed by an operator. In one . form, the blockage detection unit 70 can generate and present a graphical representation or chart of the operation of the material transfer system 10 using the recordings in the log file. The log file may include time-stamped recordings of the first load value, the first velocity sensor, the second load value, the second velocity sensor, the adjusted first load value, and/or the adjusted second load value.

At step 655, the method 600 includes the blockage being removed. This may involve conventional means in order to remove the blockage from the chute 20.

At step 660, the method 600 includes re-activating the first material transfer assembly 30 and optionally the second material transfer assembly 40 in the event it was also deactivated at step 650. This step may be achieved by an operator interacting with an input device, such as a control panel, keyboard, or the like of the blockage detection unit 70, wherein the blockage detection system communicates with the first and optionally the second drive assemblies 35, 45 for the first and second material transfer assemblies 30, 40 in order to reactivate the first and second material transfer assemblies 30, 40.

In one variation, the first and second unit 50, 60 for generating the first and second signal may be the first and second drive assemblies 35, 45. In particular, the first and second drive assemblies 35, 45 can generate the first and second signal indicative of the current being drawn by each respective material transfer assembly 30, 40. As the current being drawn by each drive assembly 35, 45 is proportional to the load being conveyed on each respective material transfer assembly, the first and second signals generated y. the first and second drive assemblies 35, 45 respectively are indicative of the load being conveyed by the first and second material transfer assemblies 30, 40 respectively;

The above embodiments may take the form of an entirely hardware embodiment, an entirely software embodiment, firmware, or an embodiment combining software and hardware aspects. Many modifications will be apparent to those skilled in the art without departing from the scope of the present invention.

Claims

1. A blockage detection unit for use in a blockage detection system of a chute, wherein the blockage detection unit is configured to:

2. The blockage detection unit according to claim 1 , wherein the blockage detection unit includes a processor associated with memory.

3. The blockage detection unit according to claim 2, wherein the blockage detection unit is configured to use the second load value which temporally offset by a temporal offset value relative to the first load value to determine if the load material entering the chute is substantially discrepant to the load of the material exiting the chute.

4. The blockage detection unit according to claim 3, wherein the temporal offset value is stored in the memory.

5. The blockage detection unit according to claim 4, wherein the blockage detection unit is configured to dynamically generate and store the temporal offset value based upon at least one of the first load value and the second load value.

6. The blockage detection unit according to any one of claims 2 to 5, wherein the blockage detection unit is configured to: obtain, from a first velocity sensor, a first velocity which the load of material is being transferred upon the first material transport assembly;

7. The blockage detection unit according to claim 6, wherein the blockage detection unit is configured to:

8. The blockage detection unit according to claim 7, wherein the blockage detection unit is configured to determine a differential value between the first comparable value and the second comparable value, wherein the blockage is detected in the event that the comparable value exceeds a comparison tolerance value.

9. The blockage detection unit according to claim 8, wherein the comparison tolerance value is stored in the memory.

10. The blockage detection unit according to claim 9, wherein the blockage detection unit is configured to dynamically generate and store the comparison tolerance value in the memory based upon at least one of the first load value and the second load value.

1 1. The blockage detection unit according to any one of claims 1 to 10, wherein in the event that the blockage detection unit detects a blockage, the blockage detection unit interrupts operation of the first material transport assembly.

12. The blockage detection unit according to claim 1 1, wherein in the event that the blockage detection unit detects a blockage, the blockage detection unit interrupts operation of the second material transport assembly.

13. The blockage detection unit according to any one of claims 1 to 12, wherein in the event, that the blockage detection unit detects a blockage, the blockage detection unit actuates an alarm.

14. A blockage detection system including:

a blockage detection unit configured according to any one of claims 1 to 5.

15. The blockage detection system according to claim 14, wherein:

16. The blockage detection system according to claim 14 or 15, wherein the blockage detection system includes:

a second velocity sensor for sensing a second velocity which the load of material is being transferred upon the second material transport assembly; wherein the blockage detection unit is configured to:

17. The blockage detection system according to claim 16, wherein the blockage detection unit is configured to:

18. The blockage detection system according to claim 17, wherein the blockage detection unit is configured to determine a differential value between the first comparable value and the second comparable value, wherein the blockage is detected in the event that the comparable value exceeds a comparison tolerance value.

19. The blockage detection system according to claim 18, wherein the comparison tolerance value is stored in the memory.

20. The blockage detection unit according to claim 19, wherein the blockage detection unit is configured to dynamically generate and store the comparison tolerance value in the memory based upon at least one of the first load value and the second load value.

21. The blockage detection system according to any one of claims 14 to 20, wherein the blockage detection system includes:

an alarm;

22. The blockage detection system according to any one of claims 14 to 21 , wherein in the event that the blockage detection unit detects a blockage, the blockage detection unit interrupts operation of the first material transport assembly.

23. The blockage detection system according to claim 22, wherein in the event that the blockage detection unit detects a blockage, the blockage detection unit interrupts operation of the second material transport assembly.

24. A material transfer system including:

a chute having an inlet and an outlet;

a first transfer assembly for transferring material toward the inlet of the chute ; a second transfer assembly for receiving material exiting the outlet of the chute; and

a blockage detection system according to any one of claims 14 to 23.

25. A method of detecting a blockage in a chute, wherein the method includes, in a blockage detection unit:

26. The method according to claim 25, wherein the blockage detection unit includes a processor associated with memory.

27. The method according to claim 26, wherein the method includes the blockage detection unit using the second load value which is temporally offset by a temporal offset value relative to the first load value to determine if the load material entering the chute is substantially discrepant to the load of the material exiting the chute.

28. The method according to claim 27, wherein the method includes storing and retrieving the temporal offset value from the memory.

29. The method according to claim 28, wherein the method includes the blockage detection unit dynamically generating and storing the temporal offset value based upon at least one of the first load value and the second load value.

30. The method according to any one of claims 25 to 29, wherein the method includes the blockage detection unit:

obtaining, from a first velocity sensor, a first velocity which the load of material is being transferred upon the first material transport assembly;

obtaining, from a second velocity^' sensor, a second velocity which the load of material is being transferred upon the first material transport assembly; and

31. The method according to claim 30, wherein the method includes the blockage detection unit:

adjusting the second load value according to the second velocity to determine second comparable value; and using the first comparable value and the second comparable value to determine if the load material entering the chute is substantially discrepant to the load of the material exiting the chute.

32. The method according to claim 31 , wherein the method includes the blockage detection unit determining a differential value between the first comparable value and the second comparable value, wherein the blockage is detected in the event that the comparable value exceeds a comparison tolerance value.

33. The method according to claim 32, wherein the method includes storing and retrieving the comparison tolerance value from the memory.

34. The method according to claim 33, wherein the method includes the blockage detection unit dynamically generating and storing the comparison tolerance value in the memory based upon at least one of the first load value and the second load value.

35. The method according to any one of claims 25 to 34, wherein in the event that the blockage detection unit detects a blockage, the method includes the blockage detection unit interrupting operation of the first material transport assembly.

36. The method according to claim 35, wherein in the event that the blockage detection unit detects a blockage, the method includes the blockage detection unit interrupting operation of the second material transport assembly.

37. The method according to any one of claims 25 to 36, wherein in the event that the blockage detection unit detects a blockage, the method includes the blockage detection unit actuating an alarm.