Patent GB-842736-A (GB)
Title: Improvements in or relating to heat exchange devices
Inventor: CHRISTIAN JOSEPH DENNIS
IPC: F28D7/02
Filed: 1957-06-24
Abstract: Material to be heated, e.g. meat scraps (for the production of tallow), is fed to the bottom of a vertical casing 100 to be raised therethrough by intermeshing helical blades 61, 62 on rotated shafts 63, 64, hollow for the circulation of steam or hot oil, which also circulates in a jacket over the outside of the casing 100.  There may be more than two intermeshing shaft-and-blade rotors and the apparatus can be operated under vacuum or pressure.  From the top of the casing 100 the material passes <PICT:0842736/III/1> <PICT:0842736/III/2> down a pipe 99 or, if there is a movable gate Figs. 7 and 8 (not shown) at the top of that pipe, the material may be deflected, if desired, past the pipe opening to a fixed shoot. Material passed down the pipe 99 may be reintroduced into the casing 100 by a feed screw 87 (heated if required) which feeds the material initially to the apparatus from a hopper 86.  For continuous operation, pipe 99 is arranged so that it can lead all or a portion of the material away from the apparatus, while the apparatus with the pipe as shown can be used for batch operation by reversal of the feed screw 87 to discharge the material through an outlet 92 when treatment is completed.  For the circulation of the heating fluid about the downpipe 99, an outer shell 76 is spaced from it to form a hollow jacket and, in the embodiment in Fig. 6, it embraces the casing 100 also, while a closure 72 of the casing has a similar outer shell 73.  The fluid jackets thus formed are subdivided into passages, Fig. 5 (not shown) and, if the apparatus is to be used for tallow, a middle portion of the closure 72 is perforated so that tallow drains through the holes into a passage at the middle of those in the shell 73 while the meat material remaining in the casing can be discharged as described.  The pipe 99 in Fig. 9 may be provided with a stack or suction for drawing off moisture; it contains a rotated shaft 107 hollow for the flow of heating fluid and bearing segmental blades, each of which throws the material against the pipe wall and then permits it to slide down to the next blade.  For withdrawal of material from the casing 100 before it reaches the top, e.g. for recirculation, a gate 108 is provided at a region along the height of the casing.  It may be opened by retraction, to the position indicated by ghost lines in Fig. 9, by means of a hand wheel 118. An outer shell 100a forms the fluid jacket around the casing 100. In another embodiment, Figs. 1 and 2 (not shown), four pairs of vertical rotors, each pair in its own casing, may be arranged to operate in parallel, feeding up to the top of a central discharge tube which is encircled by the pairs of rotors and down which the treated material discharges to a conveyer.  Treating fluid circulates in spaces between the central tube and rotor casings and through double jackets, each one spaced from the outer side of a casing of a pair of rotors to form a vertical passage at that outer side.  There are, that is, four such passages, one to each rotor pair, and material is passed from a single inlet at the top of the apparatus over a distributing cone to four shoots and thence down the passages, to be fed in at the bottom of each rotor pair.  The cone may have a gate portion permitting some of the material to by-pass the rotors and pass directly to the central discharge tube.  Treating fluid is passed into a central baffle tube inside each rotor shaft from the bottom while lateral holes adjacent the closed top end permit it to pass down outside the baffle tube to contact the inside of the rotor shaft and flow back to the bottom for discharge.  A gate, similar to the gate 108 in Fig. 9, is provided in each outer side of a rotor casing to allow recirculation to the downfeed passage if desired.