Patent GB-487399-A (GB)
Title: Improvements in or relating to a process for producing soap
IPC: C11D13/20
Filed: 1936-09-16
Abstract: <PICT:0487399/III/1> Soap powder or granules, with or without separation and collection of glycerine, are obtained by releasing a hot stream of saponified fat or the like into an evacuated chamber and continuously withdrawing the soap particles without materially imparing the vacuum.  Water vapour, with or without glycerine vapours according to the temperature and degree of vacuum, are also withdrawn continuously.  The saponification is preferably effected by continuously mixing proportioned streams of alkali solution and fat, and forcing the mixture at high pressure through an heated coil.  The soap particles may be withdrawn by a conveyer and cooled before contact with air; they may be compacted, with or without plodding, to any degree, and may be extruded to form bars or filaments; and they may be hydrated and/or mixed with fillers to any extent desired. Suitably, caustic soda solution and fat are continuously pumped in proper proportions from tanks 18, 16 respectively through a mixer 17 and a heated coil 21 so that the saponified mixture enters the pipe 26 at 440 DEG  F. and 100 lb. pressure; the mixture is discharged through a nozzle 29 into a hood 32 within a jacketed vacuum chamber 3.  The mass of soap particles collecting at the bottom is broken by agitator arms 35 and falls at 450 DEG  F. into a conveyer 4, in which it is cooled to 200-250 DEG  F. by a jacket 47 and/or by adding water and/or fillers through a pipe 44; the cooled soap is passed by a star-valve 56 to a jacketed conveyer or extrusion press 6, fitted with an extrusion nozzle 7 and a valve plate 75 so pivoted as to allow openings 73, 79 to be brought into or out of alignment and so determine the diameter of the extruded bars or filaments of soap; water and/or fillers may be added through a pipe 67.  Preferably the fat to be saponified is used as the cooling medium in the jacket 47, and thus preheated is passed to the tank 16 by a pipe 47a.  Water added through the pipe 44 is vaporized in the conveyer 4, and along with glycerine or other vapours liberated therein is returned to the chamber 3 by a pipe 46.  Each conveyer casing may be fitted with pins or knife bars 66 and/or perforated plates 64 whereby the soap is worked or plodded and wedging thereof in the conveyer screw is prevented.  The temperature and evaporative conditions within the chamber 3 are regulated by a jacket 81 surrounding all or a part thereof, and/or by introducing superheated steam, e.g. through pipes 82, 91, 86.  The vapours p  within the hood 32 flow round the lower edge and then beneath a helical baffle 93 and a conical baffle 94 to a pipe 95 and a catch-all 96 where any solids are trapped; thence by a pipe 97 to a glycerine condenser 8 and a water condenser 9 to which is attached the vacuum pump 110.  In a modified apparatus the saponified mixture is discharged into an evacuated chamber 3 through a perforated ring, the vapours move, upwards around baffles within the chamber and the soap particles drop to the bottom and are stirred by upper and lower agitator arms into a horizontal cylinder from which they are discharged through valves by a piston; the particles may then be cooled and hydrated in a conveyer 4.  Specification 367,513 is referred to.