Today in 1957, US Patent 2782013 A was issued, an invention of Edwin L. Dittrich, assigned to Pfaudler Co. Inc., for his “Lauter Tubs.” There’s no Abstract, and the OCR didn’t work very well on this one, so it’s hard to read. What I can make out is that “this invention relates to lauter tubs and has for its object to provide several improvements thereto.
A lauter tub is essentially a device for straining wort liquid from the mash-grains; and comprises -a perforated false bottom resting on and separated from the tank bottom itself by spacer studs attached to the false bottom. The tank bottom is provided-with suitable drainage openings. The invention provides a combined gear drive and hydraulic system unit motivating the shaft which revolves in a universal bearing attached to the bottom of the tank, said shaft having vertical freedom of movement through out lifting the false bottom.”
I do wish Pfaudler had kept up with the times instead of rigorously staying with the Valley Bottom Design and the “sawtooth” underflush design.
Huppmann and others surpassed them with flat bottoms and pop up underflush nozzles that were more effective and used less water.
They were tough machines though, despite the shortcomings that were later apparent. We had our two 30 footers “gutted”, replacing the internals with Huppmann Parts and drive.
Most interesting that 100 psi Gamma Jets above the plates were effective at driving out underdough beneath the plates!