GB951674A - A method of, and apparatus for controlling foam in fermenters - Google Patents

Abstract

A method of controlling foam in fermenters comprises the steps of passing a mixture of foam and entraining gases through a separator which separates the mash (liquid) content of the foam from residual gases, obtaining a measurement which is a function of the rate at which mash is separated out by the separator and admitting anti-foaming agent to the fermenter in amount dependent upon the measurement. In one embodiment, Fig. 1, foam and entrained gases from a fermenter or yeast propagator a are separated in a cyclone b and the difference between the liquid levels D h of the mash in the return pipe b2 and the fermenter a is used as a measure of the foam content in the fermenter; the pressure difference is transmitted through <PICT:0951674/C3/1> <PICT:0951674/C3/2> compressed air lines c, d, to a differential pressure regulator e, the diaphragm e3 of which transmits its movement through linkage e4 and f as a varying continuous control of the needle valve g for dispensing the anti-foaming agent. A throttle valve b3 enables the difference D h in level to be adjusted for a predetermined rate of return of the mash through pipe b2. The differential pressure regulator e may be replaced by a piston valve, Fig. 2, in which the pressure differential transmitted by pipes c and d, to chambers e1, e2, causes movement of a piston member i, i1 against a return spring p; as the piston descends, communication between the parts k1, k2, is established by way of the continually increasing transverse passage or bore i2 in the piston whereby anti-foaming agent is dispensed through the ports in the correct amount. The piston has adjusting screw l1 for stressing the spring and stop l2 for the piston. In a further embodiment, Fig. 3 (not shown), the difference in vapour pressure between the atmosphere and the input side of the separator is utilized to actuate the diaphragm e3 of Fig. 1.