Abstract: An edible high-protein flour is produced by an improved process. Cottonseed meats are dried, and then comminuted in a combination of mills having certain specifications which prevent rupturing the pigment glands of the cottonseed. Recycling of partially ground meats is practiced. This improvement is correlated with liquid cyclone separation followed by oil and solids recovery steps, thus comprising an improved process which consistently yields an edible cottonseed protein concentrate and high grade cottonseed oil. An apparatus is disclosed for interconnecting tanks in an in-line liquid process for the purpose of minimizing spills and directing overflow from the tanks at the end of the process to the tanks at the beginning of the process. This apparatus includes a number of processing tanks located in proximity to one another. Overflow conduits are provided to sequentially connect one process tank to the other from the first tank to the last tank of the process.