Venting system for a mixing apparatus

A method of filtering comprising:

• receiving, at a filter unit for a mixing apparatus, a fluid including a liquid and a gas, wherein the filter unit comprises:
• a cylindrical hydrophilic filter centered on a vertical axis and configured to;
• receive the fluid including liquid and gas;
• and
• allow the liquid to pass to an outlet while directing the gas upwards;
• and
• a hydrophobic vent filter coupled above and physically supported by the hydrophilic filter, the hydrophobic vent filter comprising:
• a hollow cylindrical filter element comprising a membrane;
• and
• a cylindrical filter capsule comprising a vent, wherein the cylindrical filter capsule and the hollow cylindrical filter element are centered on the vertical axis such that the hydrophobic vent filter is arranged to receive gas directed upwards by the cylindrical hydrophilic filter and to allow the gas to flow across the membrane and out of the vent;
• venting at least a portion of the gas across the membrane and out of the vent of the hydrophobic vent filter;
• sterilizing the liquid by the hydrophilic filter;
• and
• evacuating the sterilized liquid from the filter unit.

A hydrophobic vent filter, comprising:

• a cylindrical filter capsule;
• and
• a hollow cylindrical filter element disposed within the cylindrical filter capsule;
• wherein the filter capsule comprises a vent and the filter element comprises a membrane,
• wherein gas is vented from the hydrophobic vent filter by flowing across the membrane and out of the vent,
• wherein the hydrophobic vent filter is configured to be coupled in series to and above and physically supported by a cylindrical hydrophilic filter and to receive the gas from the hydrophilic filter, the cylindrical hydrophilic filter centered on a vertical axis and configured to allow the liquid to pass to an outlet while directing the gas upwards to the hydrophobic vent filter.