Patent GB-501199-A (GB)
Title: Improved method and apparatus for roasting coffee, cocoa beans and the like
IPC: A23N12/10
Filed: 1937-07-21
Abstract: 501,199. Roasting coffee, cocoa beans, cereals, &c. BURNS & SONS, Inc., J. July 21, 1937, No. 20201. Convention date, Nov. 14, 1936. [Class 58] The material to be roasted is fed from a hopper 9 with a pivoted shaker spout 10 into a pipe 14 leading into a perforated roasting cylinder 3 rotatably mounted on a shaft 5 in an insulated chamber 2 and provided with a trough formed by a helical flange 8, extending the full length of the cylinder. The roasting chamber is heated by a motor driven gas burner 18 situated in a chamber 19 below the chamber 2 and provided with an adjustable shutter 26 to control the, supply of air. An exhaust fan 30 draws air from the roasting chamber and forces it through a passage 34 past the burner flame in the chamber 19 whence it passes through the perforations of the cylinder 3 and the beans &c. in the trough to the upper part of the chamber 2 to be recirculated. To direct the gases through the cylinder lower and upper seals 36, 39 are arranged in the chamber 2 between its casing and the cylinder, end seals 38 also being provided : a shield 37 is provided to prevent the heated gases passing directly upwards into the material as it is fed into the cylinder. To remove material tending to clog the perforations, a brush 40 may be moved into contact with the outer surface of the cylinder and removable panels 43 and hoppers 45 are provided to facilitate cleaning. When desired gases may be withdrawn from the casing through a pipe 48 controlled by a damper 49 such gases being discharged either directly or through a separator 50. Thermometers 53 are fitted to indicate the temperature of the gases entering and leaving the chamber and automatic devices controlled by the thermometers may be used to vary the temperature of the heating flame, the volume of the gases circulated or the time or extent of exposure of the material to the heated gases. To ensure a suitable flow of the heated gases through the material the bottom of the chamber 2 tapers upwardly towards the end remote from the flame and the top is tapered in the reverse direction. The roasted material falls from the end of the cylinder into a perforated rotary cooling cylinder 69 provided with a helical flange similar to that of the cylinder 3. Air is drawn downwards through this cylinder to a chamber end pipe 67 leading to a fan 75: the pipe 67 is connected by a byepass pipe 71 to the inlet to the cylinder 59 so that loose light material may be removed from the roasted beans &c. A second pipe 73 connects the pipe 67 directly with the chamber 2 and may be used to withdraw gases therefrom instead of the pipe 48. In a modification the helical flange 8 is rotated independently of the cylinder 3 : in another the casing 2 is of uniform cross sectional area for a short distance from the end of the cylinder and an adjustable baffle is provided to present heated gases entering the cylinder for a desired part of this distance: in a further modification, the heated gases are introduced at the top and withdrawn from the lower part of the heating chamber. The Specification as open to inspection under Sect. 91 comprises also a modification in which the material passes over a series of inclined, shaking trays provided with perforated bottoms instead of through the rotating cylinder. This subject-matter does not appear in the Specification as accepted.