Patent GB-388056-A (GB)
Title: Improvements in or relating to dehydrating or drying
IPC: F26B17/10
Filed: 1931-07-15
Abstract: 388,056. Drying corn &c. ARNOLD, G. D., 291, North Main Street, Wauwatoza, Wisconsin, U.S.A. July 15, 1931, No. 20306. [Class 34 (ii).] In processes of drying materials such as corn, alfalfa, grass, teas, soya beans, or salt, by means of hot gases, the rate of feeding the material to the drying apparatus is controlled in accordance with the temperature of the hot gases, being increased as the temperature increases. In the embodiment shown, the drying apparatus is assembled on a frame 10 supported on wheels and provided with a tongue 11 for attachment to a tractor. The material is placed in a hopper 15, passes through a feed regulating gate 21 vertically adjustable by means of a screw and hand-wheel 23, and ascends on a conveyer 18 which is made in sections foldable as shown in the dotted lines when not in use. The conveyer discharges into an opening 25 through which the material is delivered by means of an airtight rotary valve so as to fall into the path of a stream of hot gases in a passageway 27 leading into the central compartment 40 of a rotary drying drum 30. The hot gases may be supplied from two combustion chambers 33 in which oil entering tangentially at nozzles 34 is burnt, air entering through a port 31 controlled by a door 32 being admixed with the products of combustion in a chamber 28. The materials are carried by the current of gas, which is produced by an exhaust fan 50, into the central compartment 40 of the drum 30, then traverse a middle concentric chamber 41, and finally return to the end of the drum through an outermost annular space 42, all the concentric chambers 40, 41, 42 being provided with lifting flanges 45, 46, which may be either radial or inclined. Owing to the increasing cross section of the concentric chambers, the velocity of the gases is successively reduced in passing from one to the other. The material and exit gases pass out of the drum by passages 47, 49, and tangential conduit 51 into a centrifugal separator 53 in which separation is effected, the wet gases leaving at the opening 54, while the dried material drops into a receptacle 56 at the inlet of a conveyer fan 57 having a discharge pipe 58 leading to a silo, bin, or bagging machine. Power may be supplied from a tractor to a pulley 60 on a shaft 61 from which a belt 62 drives a blower 63 supplying an air blast through a pipe 64 to the oil burners 34, the air blast to each burner being controlled by a valve 65, if desired automatically. The shaft 61 also supplies power for the rotation of the drum 30, for the operation of the fan 57, valve 26, conveyer 18, and for an oil pump 71 which takes part in distributing an oil supply from tanks 85 through the pipe system shown in Fig. 5 for controlling the action of the dryers. The oil supply line 86 runs through a filter 87 and the intake side of the pump 71, from which the oil is discharged at high pressure maintained by a loading valve 88 in a bye-pass line 89. From the outlet of the pump 71 a highpressure line 90 leads to the burners 34. Another high-pressure line 91 leads to a reducing valve 92 wherein the pressure is reduced so that it can be handled by a commercial thermostatically controlled valve 93 mounted on the exhaust passage 49 to respond to the gas temperature therein, being adjusted by a device 94 to operate at any desired exhaust gas temperature. Waste oil is bye-passed through a pipe 95 to the pump inlet. When the valve 93 is open, oil pressure is communicated through a low-pressure line 96 to a damper control 97 by means of which the door or damper 32 is operated, a tension spring 98 normally holding the damper closed, but being overcome by oil pressure when the valve 93 opens. A branch pipe 99 from the line 96 leads to the pressure-operated controller 100 of a valve 101 located in a highpressure branch 102 of the line 90, leading to a pressure-operated controlling device 103 for a rate-changing mechanism 78. A constantly open bye-pass valve 104 relieves pressure into the supply main 86. The rate - changing mechanism 78 is operated by power transmitted from the shaft 61 through another shaft to a chain 77. The power output shaft of the device is connected by a chain 79 with the drive shaft 80 of the conveyer 18, the shaft 80 also being connected by a chain 81 with the rotary valve through which the material passes on its way to the drum 30. Thus the speeds of the conveyer 18 and of the rotary feed valve, and also the supply of air through the damper 31 are controlled thermostatically in accordance with the temperature of the exit gases.