Patent GB-652151-A (GB)
Title: Improvements in or relating to automatic freezing apparatus
IPC: F25D31/00
Filed: 1946-05-10
Abstract: 652,151. Step-by-step conveyers. YORK SHIPLEY, Ltd. (York Corporation). May 10, 1946, No. 14160. [Class 78 (i)] [Also in Group XIII] Apparatus for use in freezing materials comprises a guiding tower 41; a plurality of material supporting trays 25 adapted to be lifted stepby-step in a stack through said tower, each of said trays having latch-engaging means and each tray being so formed as to afford an air passage substantially coextensive with the horizontal extent of the tray in which air flowing through the stack in a direction transverse to the tower may exchange heat with material contained by the trays; latch means 47 located near the bottom of the tower and adapted to coact with the latch-engaging means of the lowermost tray in the stack; means 54 for inserting trays serially beneath the stack; means 65 for withdrawing successive trays from the top of the stack; means 125 for circulating air at sub-freezing temperature across the tower and through the passages afforded by the stacked trays; and a hydraulic reciprocating lift 44 mounted at the base of the tower beneath the stack, said lift being adapted to engage an inserted tray and lift it and the stack until the latch means engage the newly inserted tray and then retreat to permit the insertion of the next tray. General operation (Figs. 1, 2).-Empty trays 25 are pushed by piston 54 along track 51 (Fig. 1), under charging-box 62 where peas are poured in and levelled off by plough 63, and into the bottom of tower 41 on to lift platform 43. Lift 44 raises the tray till it is caught by pivoted latches 47 (Fig. 2), so forcing up the stack of trays which are cooled by cold air which flows across the trays to duct 127 which feeds back the cold air over the trays in the lower part of the tower; and thus allowing piston 65 (Fig. 1) to push out the top tray to the left on to track 70. The tray slides on to guides on leaf 71 which pivots about driven shaft 73 and is counter-balanced by 75. Leaf 71 swings to the left so as to allow the tray to slide over retaining lugs 90 and past pivoted retaining latch till it strikes lugs 82 fixed on hopper 80. The shock frees the frozen peas which fall into the hopper 80. Then the shaft 73 swings the leaf the other way till the leaf strikes stop 93 on fixed discharge slide 94 and the empty tray slides out of the guides on leaf 71 and across the discharge slide 94 on to pivoted platform 97 which pivots at 98 and swings by gravity anticlockwise so that the tray slides on to fixed shoot 52 and is deposited back where it started. Reciprocating hydraulic pistons (Fig. 5)- Each piston 54 and 65 has buffer spring 58 and stop 56. Lug 61 of piston 54 works arm 59 of limit switch ILS and piston 65 operates simi. larly limit switch ELS. Descent of tray (Fig. 4).-As the tray passes from leaf 71 into slide 94 it is braked by lateral springs 104 adjustable by screws 105, and as it slides to the bottom of platform 97 its impact is cushioned by shock-absorber 107. As the platform 97 swings downwards between guards 114 and about pivot 98 its impact is lessened by its striking actuating lug 112 of shock-absorber 109, and as it swings back it strikes the other actuating lug 113 of this shock absorber. Along shoot 52 the tray is braked by adjustable shoe 115. Oscillating leaf 71 (Fig. 6).-Reciprocation rack 86 is worked by piston 85 and meshes with spur-wheel 87 integral with hub 91 which rotates shaft 73 of the leaf 71 through lost-motion lug 92 and by means of lug 96 operates limit switch DLS. The machine is worked automatically by hydraulic means controlled by an electrical circuit governed by the switches DLS, ELS, ILS and by a clock. Trays (Figs. 17, 18).-A tray may be formed (Fig. 17) with screen base 28, channel side pieces 26 and smaller side pieces 27 over which the refrigerating air may pass. Or it may be formed with a false bottom 36 for the passage of the air and the effective height of floor 33 may be varied by placing on it a filler plate.