Patent GB-612014-A (GB)
Title: Improvements in or relating to the manufacture of soap
IPC: C11D13/04
Filed: 1946-01-21
Abstract: <PICT:0612014/III/1> Soaps are washed free from glycerine &c. by continuously mixing a stream of soap with a stream of lye (which may be lye in the sense commonly used in soap manufacture, or may be a glycerin-free wash liquor consisting of an aqueous solution of common salt or other electrolyte), washing the soap with the lye by agitation, and thereafter maintaining a substantially quiescent flow of the mixture in order to allow the lye to separate by gravity from the soap.  The washed soap and the settled lye containing glycerine washed out of the soap are then separately withdrawn.  The soap may be passed through several pairs of localities of agitation and settling in series and may be washed and the lye settled therefrom in each pair of localities.  The flow of soap from pair to pair of localities may be in countercurrent to, or concurrent with the flow of lye from pair to pair of localities.  Parallel flows of lye may be provided through the pairs of localities and agitation and settling may take place in contiguous spaces of a single vessel. Alternatively, agitation and settling may take place in separate but communicating vessels.  The movements of soap and lye are brought about by means of steam injectors and agitation of soap and lye may be carried out by injecting them by means of a steam injector through a baffled vessel.  A stream of lye may be injected into a layer of soap or vice versa.  A washing vessel may be supplied with an upper layer of soap curd and a lower layer of lye, and the soap to be washed injected into the lower layer of lye and allowed to rise through this layer to the top.  At the same time, washing lye is injected into the upper layer of soap curd and allowed to fall through the soap curd to the bottom of the washing vessel.  Washed soap is withdrawn from the layer of soap curd and lye from the lower layer.  The process may be carried out in two or more stages, wherein the lye withdrawn from a later stage is injected into the soap curd layer of an earlier stage and the soap withdrawn from an earlier stage injected into the lye of a later stage.  Where agitation and settling take place in separate but communicating vessels the apparatus may consist of one or more shallow separating vessels or trays, each provided with a distributor for introducing a soap/lye mixture and a weir spaced apart from said distributor over which the settled soap formed as the mixture passes from the distributor to the weir, can flow; a mixing vessel for each tray for intimately mixing a stream of soap with a stream of lye and connected to said distributor; and outlets for the soap passing over the weir and for the lye collecting in the bottom of the tray.  The distributor may comprise a funnel placed in the centre of the shallow separating vessel or tray and the weir may be placed along the side walls of the separating vessel.  Alternatively, the distributor may be placed at one of the separating vessels and may consist of a distributing pipe behind a baffle plate, while the weir is placed at the opposite end of the vessel.  When agitation and settling take place in adjacent spaces of a single vessel the latter may be deep and provided at the bottom with an inlet for soap or soap/lye mixture and round the sides at the top with a weir for soap withdrawal; there are also provided a diffuser for introducing a continuous stream of lye into the upper portion of the vessel and outlets for the soap passing over the weir and for the lye collecting in the bottom of the vessel.  A mixing vessel may be provided for intimately mixing a stream of soap with a stream of lye before introducing the soap into the deep vessel. As shown, soap to be washed enters the sump tank 106 via the pipe 105 where it meets lye withdrawn along the pipe 97 from the layer L5 of the settling tray 75 and injected upwards by the steam injector 100 along the pipe 104.  The mixture of soap and lye then passes down the pipe 95 into the steam injector 80 which injects it along the pipe 77 into the baffler agitation vessel 71 and thence out through the pipe 83 into the funnel 86 of the settling tray 74 where the soap and lye settle into the layers C4 and L4 respectively.  The flow of the soap/lye mixture through the baffled mixing vessel 71 is sufficiently turbulent to ensure the degree of agitation necessary for the extraction of glycerin from the soap by the lye.  The lye is withdrawn from the layer L4 to pass out of the first settling tray 74 by the pipe 96 while the soap overflows a weir into the trough 89 where it meets lye from the layer L6 in the tray 76 which has been injected upwards via pipe 98, steam injector 101 and pipe 103.  This further mixture of soap and lye is injected into the agitation vessel 72 through the pipe 92, the steam injector 81 and the pipe 78, whence it is transferred to the settling tray 75 along the pipe 84 and the funnel 87.  Again the lye settles out and is withdrawn along the pipe 97 to be injected upwards as mentioned above, while the soap overflowing into trough 90 meets fresh lye introduced by the pipe 117 from the injector 99 fed by the brine, steam and water pipes 107, 108 and 109 respectively.  This soap/lye mixture is injected into the agitation vessel 73 via pipe 93, steam injector 82, and pipe 79, from which it is transferred to the settling tray 76 through the pipe 85 and the funnel 88.  Here again the lye settles out, this time into the layer L6 from which it is withdrawn to be injected upwards as mentioned above.  The soap which passes into the upper layer C6 then overflows into the trough 91 and is withdrawn from the process through pipe 94.  Specifications 549,386, 549,387, 573,787 and 605,995 are referred to.