Breast pump and expression kit for a breast pump

An expression kit for a breast pump for extracting breast milk from a human teat, the expression kit comprising:

• a breast pump body comprising a first pressure chamber and a second pressure chamber adjacent to the first pressure chamber;
• a hydrophobic breathable membrane separating the first pressure chamber and the second pressure chamber, the hydrophobic breathable membrane comprising a hybrid membrane structure comprising both a woven layer and a non-woven layer,
• wherein the hydrophobic breathable membrane is gas-permeable and liquid-impermeable when in contact with a liquid in a milk path, thereby separating the first pressure chamber from the liquid in the milk path while continuing to exchange gas with the second pressure chamber,
• wherein the woven layer is liquid-impermeable;
• and
• a restrictor for reducing a surface area of the hydrophobic breathable membrane.

An expression kit for a breast pump for extracting breast milk from a human teat, the expression kit comprising:

• a breast pump body comprising a first pressure chamber and a second pressure chamber adjacent to the first pressure chamber;
• a hydrophobic breathable membrane separating the first pressure chamber and the second pressure chamber, the hydrophobic breathable membrane comprising a hybrid membrane structure comprising both a woven layer and a non-woven layer, wherein the hydrophobic breathable membrane is gas-permeable and liquid-impermeable for separating the first pressure chamber from liquid in a milk path,
• wherein the woven layer faces the second pressure chamber, and the non-woven layer faces the first pressure chamber,
• wherein the hydrophobic breathable membrane is gas-permeable and liquid-impermeable for separating the first pressure chamber from liquid in the milk path;
• and
• a restrictor for reducing a surface area of the hydrophobic breathable membrane.