GB1054405A - - Google Patents

Abstract

1,054,405. Fumigating stored potatoes &c. CORNERCROFT ENGINEERING Ltd. Nov. 26, 1963 [Nov. 29, 1962], No. 45096/62. Heading A2Q. In apparatus for fumigating stored potatoes or other tubers with the vapour of a liquid sprout-inhibiting depressant, such as 3:5:5-trimethyl hexanol or "Nonanol" (Registered Trade Mark), carried in a current of air, the depressant is fed, from a reservoir 14, through a pipe 15 and a drip-feed valve 18 provided with an observation glass window 181, on to a vaporizer 19 located in the lower part of an open-ended cylinder 10, whose upper end is guarded by a wire-mesh grid 101. The pipe 15 is made of material, such as copper, having good electrical and thermal conductivity and some electrical resistance, and forms part of a low-voltage, e.g. 2-volt, electric circuit including the output winding T1 of a step-down transformer T, having an input winding T2 in a high-voltage, e.g. 230-volt, electric circuit. The pipe 15 is heated when it conducts low-voltage current. The pipe 15 has a perforated coiled portion 151, which extends into the reservoir 14 to heat the depressant and lower its viscosity. An axial-flow fan 11, driven by a two-speed electric motor 12, is mounted in the upper part of the cylinder 10 to propel air downwardly past the vaporizer 19. The resulting current of air mixed with vaporized depressant is passed, through ducting 13, into a stack of potatoes &c. (not shown). The flow of depressant to the valve 18 can be regulated by a manually operated valve 16 and a valve 17 actuated magnetically by a solenoid in the high-voltage circuit, which includes the heating elements of the vaporizer 19. A thermostat 21 regulates the temperature of the depressant in the reservoir 14, by controlling the high-voltage current flowing through the winding T2. The apparatus comprises a switch for switching the motor 12 from low speed to high speed. When the motor 12 is switched to low speed, the high-voltage circuit is energized, the pipe 15, 151 and the depressant are heated by the resulting low-voltage current, the valve 17 is opened, the vaporizer 19 is heated and a mixture of depressant vapour and air is supplied to the potatoes &c. When the motor is switched to high speed, the high-voltage circuit is de-energized and a stream of ventilating air is delivered to the potatoes &c.