Patent GB-503491-A (GB)
Title: Improvements in or relating to the storage of vegetable produce including fruit
IPC: A23B7/148
Filed: 1937-10-05
Abstract: 503,491. Storing crops. TOLEDO SCALE MANUFACTURING CO. Oct. 5, 1937, No. 26880. Convention date, Feb. 18. [Class 5 (i)] [Also in Groups VI and X] In a process for storing vegetable produce, including fruit, in which, as described in Specification 240,507, [Class 137], a slow and uniform current of air is passed with controlled flow through a body of the produce so as to prevent undue accumulation of carbon dioxide, deposit of water and undue rise of temperature without excessive drying of the produce and so as to ensure that such a percentage of carbon dioxide remains that will maintain a state of reduced respiration in which further ripening is prevented, the rate of air flow is changed automatically on a rise or fall of the temperature of the outer atmosphere surrounding the storage chamber so that the rate of flow is automatically increased or decreased through the agency of heat-responsive means upon a rise or fall respectively in the 'temperature of the outer atmosphere. In one form, an insulated cabinet 20, Fig. I, is employed, the upper end of which has perforated partitions 24, 25, 26 the space between which is filled with porous insulating material, the number and size of the perforations in partition 25 being larger and in partition 26 still larger than in partition 24. Similar partitions 27, 28, 29 and packing are provided at the bottom of the cabinet, these partitions being similar to partitions 24, 25, 26 respectively. The air is supplied to the cabinet 20 by means of a fan 23 actuated by a motor 31, Fig. II, the speed of which is changed on a rise or fall of the outside temperature by heat-responsive means 34 which short-circuits a resistance 33 in series with the motor when the temperature exceeds a certain value and connects a resistance 35 in parallel with the motor when the temperature is below a certain value. To provide for increasing the rate of flow of the air through the cabinet earlier when there is a rapid rise in the outside temperature and for decreasing the rate of flow earlier when the outside temperature falls rapidly, parallel heat-responsive elements 36, 37, 38, Fig. IV, are provided, the elements deflecting to the right as the temperature rises and to the left as it falls, the outside elements 37, 38 being insulated so that on a rapid rise the element 36 will contact with element 37 and a relay 44 is energized and short circuits a resistance 42 in the motor circuit. On a rapid fall, elements 36, 38 contact and a relay 43 is energized to put the resistance 41 in series with the motor. When the temperature changes gradually no electrical contact is made until a certain temperature is reached which ensures contact between the respective parts of elements taking place when the temperature has risen above or fallen below a certain value. To provide for reversal of the direction of rotation of the fan, the air being preferably taken in at the bottom of the compartment and passing upwards therethrough when the inside temperature is below that of the outside temperature and in the reverse directon when the outside temperature is lower than the inside, there is associated with the cabinet a differential heatresponsive means 59, Fig. XI, a relay 60 being operated by the heat-responsive means to effect by double-throw contacts a reversal of the direction of the current through motor 31. In this form, the motor speed may be controlled by means of resistances 41, 42 and relays 43, 44 operated by means responsive to temperature as shown in Figs. II or IV. In a further form, the regulation of the air flow according to the outside temperature may be obtained by using a fan in which the pitch of the blades is regulated according to the temperature, e.g. by connecting them to the hub of the fan by strips of metal which twist to vary the pitch as the temperature changes, or by making the blades 45, Fig. V, of this metal. In another form, Fig. VIII, the air supply may be controlled by regulating the size of an orifice 46, of triangular, rectangular, &c. shape, through which the air flows by means of a damper 48 sliding in guides 62, with pins 53 which prevent the orifice being completely closed. A pin 49 pivoted on damper 48 has a notch in which engages a heatresponsive strip 50, the other end of which is secured to a standard 51.