Breast pump

A breast pump, comprising:

• a chamber defined by an upper portion and a lower portion,
• wherein the upper portion includes an upper wall of the chamber and an upper part of a sidewall of the chamber,
• wherein the lower portion includes a lower part of the sidewall and a base of the chamber,
• wherein a lower end of the upper part of the sidewall extends into the lower part of the sidewall and an upper end of the upper part of the sidewall at least partially overlaps an upper end of the lower part of the sidewall, and
• wherein the chamber has a vacuum port formed in the upper wall of the chamber;
• a membrane including a first section mounted between the upper part of the sidewall and the upper end of the lower part of the sidewall with the first section of the membrane wrapping around the upper end of the lower part of the sidewall and further including a second section receivable in the chamber to separate the chamber into first and second spaces,
• wherein the second section of the membrane is deformable in the chamber in response to a reduction of pressure in the first space;
• and
• a limiter in the first space of the chamber to limit deformation of the second section of the membrane,
• wherein the second section of the membrane is free to deform in the chamber between:
• a neutral condition, in which the second section of the membrane is at a set position such that the second section of the membrane is proximate to a surface of the base of the chamber,
• an operating condition in which the second section of the membrane is deformed to a set position that is proximate to a surface of the upper wall of the chamber and spaced from the limiter, wherein the operating condition corresponds to when a predetermined reduction of pressure is imparted on the second section of the membrane in the first space of the chamber, and wherein the second section of the membrane is configured to cyclically move between the neutral condition and the operating condition during a pumping cycle, and
• a limited condition in that the limiter is configured such that the second section of the membrane locates against the limiter to limit deformation of the second section of the membrane in the chamber when a reduction of pressure in the second space is equal to or exceeds a threshold value in order to restrict the pressure reduction in the second space,
• characterized in that one of:
• the limiter includes at least one protrusion extending from the upper wall of the chamber relative to the vacuum port within the first space of the chamber to define at least one air channel between the upper wall of the chamber and the second section of the membrane when the second section of the membrane locates against the limiter, or
• the limiter includes at least one recess formed within the upper wall of the chamber relative to the vacuum port within the first space of the chamber to define at least one air channel between the upper wall of the chamber and the second section of the membrane when the second section of the membrane locates against the limiter.