Today in 1985, US Patent 4505941 A was issued, an invention of David W. Raines, for his “Lauter Tun For The Filtration Of Wort During Brewing.” Here’s the Abstract:

Lauter tuns are used for the filtration of wort during brewing. In use the wort runs off through a filter bed and has to be collected. Hitherto the bottom of such tuns have been flat having a number of holes through which the wort runs. If the bottom is ostensibly flat, problems can arise in that puddles accumulate in any undulations leading to possible spoilation of the wort. The bottom of a tun in accordance with the invention is formed with a series of straight parallel valleys extending across the tun and having spaced wort collection points for connection to straight wort mains or manifolds located beneath the tun.