MEASUREMENT OF BULK DENSITY OF THE PAYLOAD IN A DRAGLINE BUCKET

• US 20120136542A1
• Filed: 10/25/2011
• Published: 05/31/2012
• Est. Priority Date: 10/26/2010
• Status: Active Grant

• Current Assignee: CMTE Development Limited
• Original Assignee: CMTE Development Limited
• Inventors: Upcroft, Benjamin, Shekhar, Rajiv Chandra, Bewley, Alex Joseph, Lever, Paul J.A.
• Granted Patent: US 8,930,091 B2
• Time in Patent Office: Days
• US Class Current: 701/50
• CPC Class Codes: E02F 3/48 Drag-lines
• CPC Class Codes: E02F 9/26 Indicating devices E02F5/145 takes precedence

Abstract

In particular embodiments of the technology, the bulk density of the payload in the bucket of a large electric dragline is measured during the carry phase of dragline operation by scanning the loaded bucket using a boom mounted scanner to provide data relating to the volume of the loaded bucket. Suitable methods can further include calculating the volume enclosed by the surface of the payload and the known base and sides of the bucket to give payload volume, and dividing the payload volume into payload weight data derived from rope length and motor current data to give the payload bulk density. Methods of screening data points originating from surfaces other than the bucket and payload, and methods of dealing with bucket ope and sway are also described and claimed.

Claims

1. A method of measuring the bulk density of the payload in a dragline bucket having a base and sides, during dragline operation, comprising the steps of scanning a loaded dragline bucket during an operating cycle of the dragline to provide mathematical data relating to the volume of the loaded bucket, calculating the volume enclosed by the surface of the payload and the known base and side surfaces of the bucket from the mathematical data to give the payload volume, and dividing the payload volume into the payload weight to give the payload bulk density.

2. A method as claimed in claim 1 wherein the step of scanning the loaded bucket during an operating cycle of the dragline occurs during the carry phase of the cycle, between the lifting phase and the dumping phase.

3. A method as claimed in claim 1 wherein the step of scanning the loaded bucket is performed by moving the bucket during the carry phase through the beam of a suitable scanner.

4. A method as claimed in claim 3 wherein the suitable scanner comprises a laser scanner.

5. A method as claimed in claim 3 wherein the suitable scanner comprises a radar scanner.

6. A method as claimed in claim 1 wherein the mathematical data is analysed to screen out data points originating from surfaces other than those of the bucket and the payload.

7. A method as claimed in claim 1 wherein the step of calculating the volume enclosed by the surface of the bucket and the known base and side surfaces of the bucket includes analysing the collected data to rebuild the bucket structure by estimating the bucket motion between scans to allow for bucket sway.

8. A method as claimed in claim 1 wherein the step of calculating the volume of the loaded bucket includes the steps of collecting hoist and drag rope length data and using that data to determine the bucket displacement between each scan.

9. A method as claimed in claim 1 wherein the step of calculating the volume of the loaded bucket includes measuring the displacement between each scan as a function of bucket velocity as it passes through the scanner beam and using the displacement to rescale bucket points in a direction orthogonal to the scanner beam.

10. A method as claimed in claim 1 wherein the steps of calculating the volume enclosed by the surface of the payload and the known base and sides of the bucket include determining the pose of the loaded bucket in order to provide reference surface data and enable known features of the bucket to be deducted from the volume calculation.

11. A method as claimed in claim 1 wherein the payload volume is determined using a height grid representation.