Improvements in or relating to apparatus for extracting soluble constituents from tea leaves or other vegetable matter in a coarsely divided or granular form

摘要

901,285. Extracting apparatus. THORNHILL, J. H. R. Feb. 1, 1961 [Nov. 3, 1959], No. 37293/59. Classes 81 (1), 127 and 129. In an apparatus for the liquid extraction of coarsely-divided or granular vegetable matter, e.g. tea, coffee, sugar beet, or pharmaceutical vegetable matter, the vegetable matter is contained in pans, each with an opening or openings in its base, which are stacked vertically and the extracting liquid is passed upwardly through the stack, there being also provided means for removing the bottom pan and adding a pan at the top. As shown, a base 10 with an open top cavity 11, has resting upon it a number of pans 21, topped by a head 16, the base and the head being provided with a liquid inlet 43 and an outlet 44 respectively. Each pan, Fig. 5 (not shown), and also the base have an upwardly facing groove around the top edge to take a packing ring to make fluid-tight joints between the base, pans and head. Each pan has a ring of apertures in its base surrounding a central stud which is grooved to locate and retain a flexible disc, the outer edge of which is free, covering these apertures, which acts as a non-return valve permitting upward flow of the liquid. Mesh screens are mounted with radial rib spacers above and below these bases. The head, Fig. 6 (not shown), has a similar non-return valve and mesh screens fitted to it. In use, hot water is passed from a boiler through a valve 42 to the cavity in the base and thence upwards through the stack of pans to the head outlet which is connected by a flexible conduit 45 to a receiving tank. At the end of a predetermined time controlled by a timer, valve 42 is closed, an hydraulic ram is operated to raise the head which when raised by a height slightly greater than the height of one pan, by means of lifting claws on the bottom of two links that are fixed to it, lifts up all but the lowermost of the pans which pan is then ejected by the ram 56. The pan at the lower end of the ramp 58 slides under gravity into the space between the uppermost pan and the head, and then the head and pans are lowered again. The valve 42 is then re-opened and the cycle repeated continuously. The pans may be filled between cycles by means of a hopper 66 placed above the conveyer 59. An alternative form of apparatus is described whereby the head remains fixed and the base is lowered in order to effect the removal and replacement of pans.