Today in 1968, US Patent 3407121 A was issued, an invention of Gerald Einar Wilson and Louis A. Le Seelleur, assigned to John Labatt Breweries, for their “Fermenter Yeast Cropping and Washing Device.” There’s no Abstract, although in the description it includes these claims:
A fermenter vessel containing a yeast cropping and cleaning device consisting of a rotatable header pipe in the upper portion of the vessel with an end of the pipe extending outside the vessel and a series of orifices opening from the header into the vessel. The orifice outlets are offset a substantial distance radially from the axis of rotation of the header pipe either by providing an offset portion in the header pipe itself or by providing a series of branch pipes extending laterally from the header pipe with nozzles on the outer ends thereof. Conduit means connected to the external end of said header pipe by means of a connector and suction means associated with said conduit for cropping the yeast.
This invention relates to a yeast cropping and washing device for closed fermenting vessels used in the brewing industry.
The fermentation of wort is one of the most important steps in the brewing process. Brewers yeast, having the ability to assimilate simple nitrogenous compounds and reproduce and break down sugars to carbon dioxide and alcohol are introduced into the wort, whereupon through a controlled biological fermentation process, the wort is transformed into beer. The fermentation of wort is usually an operation carried out under relatively low pressure (1-3 p.s.i.g.) in large metal fermenting vessels capable of holding thousands of gallons of wort. The modern fermenting vessel is a closed vessel such as that described in applicants co-pending application entitled, Multipurpose Process Vessel for Heat Transfer Operations.
During the fermentation, top fermenting yeast forms on the surface of the liquid in the vessel and this is normally removed by skimming or is allowed to work over the rim of a tank into chutes or troughs. In the closed vessel it is, of course, necessary to use some form of yeast cropping device and according to the present invention a new device has been developed which can be used both for cropping yeast from the surface of the beer in the fermenter and for cleaning the fermenter after the beer has been removed.
The cropping and cleaning device according to this invention consists of a horizontally extending pipe which is rotatable within the fermenter and the rotatable pipe has a series of orifices which are adapted to draw off yeast from the fermenter or to spray cleaning solution into the fermenter. The pipe is arranged such that by rotating it the elevation of the orifices can be varied to permit the yeast to be drawn off to the desired level. One end of the rotatable pipe has a fluid connection to an external pipe through a connector which permits relative rotation between the two pipes while fluid is passing through. Suitable valve means are provided so that cleaning solution can be forced into the vessel or yeast can be drawn out of the vessel through the connector and rotatable pipe.