Applying filter aid precoat to filter for beer, oil etc. - with exclusion of air from precoat to protect prod. from oxidation

摘要

The process is of the type in which the aid is mixed into water in a vessel from which the mixt. is passed through a closed circuit including the filter, where a precoat is deposited on the support. Once filtration of a liq. starts, a supplementary quantity of filter aid is injected into the liq. in mixt. from the vessel. All water used for making up the mixt. is now first deaerated. The vessel is closed to atmos. and headspace in the vessel is filled with an inert gas, pref. nitrogen or carbon dioxide. Inert gas is pref. blown through the vessel to purge air from the headspace. No air is present in the water and aid mixt. forming the precoat or in the supplementary precoat injected into the liq. The prod. is thus protected against oxidation so that it will keep longer and taste better.