GB724695A - Improvements relating to continuous weighing of powdered materials - Google Patents

Abstract

724,695. Automatic weight-control systems. SMIDTH & CO. AKTIESELSKAB, F. L. March 4, 1953 [March 5, 1952], No. 6055/53. Class 38 (4). [Also in Groups XVIII and XXXVIII] The rate of supply of a powdered material is measured or retroactively controlled to a constant value by weighing apparatus comprising an inclined pneumatic channel conveyer with means for forcing air upwards through material resting on air air-permeable support in the channel so that it is fluidized and flows along the support. In Fig. 8 air is supplied by pipes 80 to the bottom of material flowing in a channel and the difference in air pressure at the top and bottom of the material, which is proportional to the weight of material, is measured by a ring balance 84. The latter rotates a shaft carrying a mercury tube 88, the mercury in which makes and breaks various switch contacts sealed into the tube and energizes two or at most three of a circular arc of electromagnets 89 wound so that they alternately present south and north poles to an armature 93 mounted on an arm 92. Partitions 71a, 72a seal off the portion of air chamber 70 below this section of channel from the rest of the air chamber which is connected by a by-pass pipe 75. The arm 92 measures the weight of material in this section or retroactively operates through a cable a valve in the material supply pipe to render the supply constant, or a valve in an air-supply pipe for fluidizing the material and hence its rate of flow at a point upstream of the channel section for the same purpose. The arm 92 may also be one control element of an integrator indicating the total flow during a period.