GB262989A - Apparatus for heat treating raisins or other dried fruit - Google Patents

Abstract

262,989. Marks, E. C. R., (Sun-Maid Raisin Growers of California). Feb. 17, 1926. Treatment by heating and steaming.-Apparatus for use in the treatment of dried fruit, more especially according to the process described in Specification 262,988, [Class 49, Food &c.], comprises two non-communicating cylinders 1, 7, the inner cylinder 1 having a spiral conveyer 2 for agitating and conveying the fruit therethrough, together with means, such as pipes 8, for applying heated vapour to the fruit in this cylinder. Means are also provided for externally heating the inner cylinder 1, for example by passing hot gas between the cylinders 1, 7, and for charging and discharging fruit while keeping the cylinder 1 sealed from the outer atmosphere. In the construction described, raisins are delivered to the cylinder 1 through an airtight gate B, formed of vanes 50 fitted within a housing, and discharged through similar gates D, D'. The conveyer 2, which has perforations 54 to allow some of the fruit to fall through, is driven by a shaft 3, projecting through stuffing boxes 51, from which the revolving gates are also driven, for example by chains 53. The outer cylinder 7 has heat insulation 55. Gas heated to 800' F. passes to between the cylinders through pipe 5, leaving through pipe 6 to a reheater from which it is returned to pipe 5. Steam superheated to about 230-250‹ F. and at about atmospheric pressure is passed into the cylinder 1 through the pipes 8 which have control valves 9. The apparatus is inclined towards the discharge end. The raisins enter the cylinder at about room temperature, and to prevent scorching pass through in a short time, e.g. 12 seconds in a 12 foot container, the heat and vapour having a puffing action thereon. Free vapour is withdrawn through a pipe 10 from the fruit before its discharge.