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US 4,361,052 AGranted
Sampling of granular material for analysis
AssigneeThe University of Queensland
InventorsRobert W. Nicol, Martin Gottschall, Geoffrey Lyman
Life of this patent
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Abstract
A method of and apparatus for sampling granular material where a substantially vertical sampling tube is subjected to axial, and/or rotational oscillations to reduce the vertical vector component of the friction force between the granular material and the tube to be substantially equal to the weight of an elemental disc of the material in the sampling tube. The acceleration force on the disc is substantially zero and the material has no pressure gradient or bulk density gradient.
Claims13
A method of conveying granular material through a sampling tube for analysis including the steps of:
- (a) feeding granular material to the sampling tube;
- (b) subjecting the sampling tube to oscillations to reduce the frictional force between the granular material and the wall of the sampling tube to enable the granular material to pass through the tube with substantially no pressure gradient or bulk density gradient, wherein the velocity and amplitude of the oscillations are selected such that the vertical vector component of the frictional force on an elemental disc of granular material in the bulk of the material is equal to or just less than the weight of the elemental disc so that the vertical velocity of the elemental disc is substantially constant;
- and
- (c) discharging the granular material from the sampling tube.
1 more element
A method of conveying granular material through a sampling tube for analysis including the steps of:
- (a) feeding granular material to the sampling tube;
- (b) subjecting the sampling tube to oscillations to reduce the frictional force between the granular material and the wall of the sampling tube to enable the granular material to pass through the tube with substantially no pressure gradient or bulk density gradient, wherein the velocity and amplitude of the oscillations are selected such that the vertical vector component of the frictional force on an elemental disc of granular material in the bulk of the material is not greater than the weight of the elemental disc so that the vertical velocity of the elemental disc is substantially constant;
- (c) analyzing the granular material as it passes through the sampling tube;
- and
- (d) discharging the granular material from the sampling tube.
2 more elements
Apparatus for conveying granular material through a sampling tube for analysis including:
- a sampling tube having an inlet and an outlet;
- means to support the sampling tube for oscillating movement;
- means to feed granular material to the inlet of the sampling tube;
- means for oscillating the sampling tube at a velocity and amplitude to reduce the frictional force between the granular material and the wall of the tube to enable the granular material to pass through the sampling tube with substantially no pressure gradient or bulk density gradient, said osciallating means being such that the velocity and amplitude of the oscillations are selected so that the vertical vector component of the frictional force on an elemental disc of granular material in the bulk of the material is equal to or slightly less than the weight of the elemental disc so that the vertical velocity of the elemental disc is substantially constant;
- and
- means for discharging the granular material from the outlet of the sampling tube.
3 more elements
Apparatus for conveying granular material through a sampling tube for analysis including:
- a sampling tube having an inlet and an outlet;
- means to support the sampling tube for oscillating movement;
- means to feed granular material to the inlet of the sampling tube;
- means for oscillating the sampling tube at a velocity and amplitude to reduce the frictional force between the granular material and the wall of the tube to enable the granular material to pass through the sampling tube with substantially no pressure gradient or bulk density gradient, said oscillating means being such that the velocity and amplitude of the oscillations are selected so that the vertical vector component of the frictional force on an elemental disc of granular material in the bulk of the material is not greater than the weight of the elemental disc so that the vertical velocity of the elemental disc is substantially constant;
- means for discharging the granular material from the outlet of the sampling tube;
- wherein:
- the sampling tube is substantially vertical, of substantially constant cross-section, and is supported for rotational motion in a frame;
- and
- the means for generating rotational oscillations in the sampling tube includes a substantially vertical drive shaft, at least one eccentric lobe on the drive shaft, a substantially vertical rocker shaft, at least one rocker arm on said rocker shaft;
- a drive link connecting the eccentric lobe to the rocker arm;
- diametrically opposed axles on the sampling tubes and a pair of connecting links connecting one of said axles to the adjacent end of the rocker arm,
- whereby the rotational motion of the drive shaft is translated into rotational oscillation of the sampling tube.
9 more elements
Dependencies are inferred from the claim text.