GB707875A - An improved apparatus for separating a representative sample from bulk granular, powdered or liquid material - Google Patents

Abstract

707,875. Sampling granular or powdered material. NATIONAL COAL BOARD. June 7, 1951 [June 8, 1950], No. 14358/50. Class 58. [Also in Group XXX] An apparatus for separating a representative sample from granular or powdered material comprises a hopper or the like to which the bulk material in granular or powdered form can be charged and from which it will fall by gravity, a deflecting vane below the hopper, and means for alternately moving the deflecting vane in one direction and then in the other so that a stream of bulk material falling from the hopper is divided and a representative sample of the bulk material is discharged thereby at one side of a partition and the remainder to the other side of the partition, the timing of the movements of the deflecting vane being effected automatically and determining the volumetric ratio of the sample to the bulk from which it is separated out. The means for moving the deflecting member can be adjusted so that the time interval during which it remains at rest when moved in one direction can be varied with respect to the time interval during which it remains at rest when moved in the other direction so that the volumetric ratio of the representative sample to that of the bulk material can be varied as desired. As shown the apparatus is provided with a flanged hopper 5 fitted in the upper end of a casing 6 which is or can be connected to a suitable receptacle for holding the material. Towards the foot of the hopper is a deflecting member in the form of two central partitions 7, 8 placed back to back and two downwardly and oppositely outwardly inclined shoots 9, 10 extending from the partitions 7, 8 respectively. The deflecting member is rigidly secured to a transversely extending spindle 11 to which a partial rotary movement is imparted first in one direction and then in the other. Below the deflecting member the casing is provided with two discharge outlets 12, 13 into which the shoots 9, 10 respectively discharge. One side of the hopper is provided with a flap 14 hinged at 15 to which flap is connected a screw threaded spindle 16 passing through a nut 17 fitted to the side of the casing so that it can partake of a rotary but not an axial movement. Consequently by rotating the nut the flap can be turned about its hinge so that the opening at the foot of a hopper and therefore the rate of discharge can be regulated. To the sides of the hopper 5 are secured a pair of inverted U frames 18 the limbs of which carry adjustable screws stops 19 against which the partitions 7 and 8 abut. The means shown for tipping the pivoted deflecting member embodies two so!enoids 21 (not shown), 22 or electromagnets, the cores or armatures 21a (not shown), 22a of which are suspended by means of springs 21b (not shown), 22b from a cross arm 23 fast on the spindle 11. The solenoids or electromagnets are alternately energized fom the mains in a circuit involving a time switch which controls by means of a variable resistance the time interval between the energizing of the solenoids and the time interval between the different positions of the deflecting member whereby the volumetric ratio of the representative samples to the bulk material passed through the apparatus can be varied. The flow of bulk materials can be seen through glazed panels 20 provided in the sides of the casing below the hopper.