Pumps with container vents

A refill unit comprising:

• a container for holding a fluid;
• a pump housing secured to the container;
• the pump housing having an annular collar for securing the pump to the container;
• a seat member located at least partially within the annular collar;
• an air chamber located within the pump housing below the seat member;
• one or more air passageways in the collar for providing air to the air chamber;
• a vent valve secured to the seat member for controlling the flow of air from the air chamber into the container;
• a compressible liquid pump chamber located in the housing;
• a liquid inlet valve secured to the seat member for allowing liquid to flow from the container into the compressible pump chamber;
• and
• a liquid outlet valve located downstream of the pump chamber.

A refill unit comprising:

• an inverted container for holding a fluid;
• the inverted container having a neck portion located on the bottom of the inverted container;
• a pump housing secured to the neck of the inverted container to pump liquid;
• the pump housing having a collar;
• an air chamber located within the pump housing;
• a vent valve located at least partially within the air chamber, selectively opening to vent the container;
• one or more air passageways between the collar and the neck of the container for providing air to the air chamber;
• a compressible liquid pump chamber located in the housing;
• a liquid inlet valve for allowing liquid to flow from the container into the compressible pump chamber;
• and
• a liquid outlet valve located downstream of the pump chamber.

A refill unit comprising:

• a container for holding a fluid;
• a pump housing secured to the container;
• the pump housing having an collar for securing the pump to the container;
• a seat member;
• an air chamber located within the pump housing below the seat member;
• one or more air passageways formed between the collar and the neck for providing air to the air chamber;
• a vent valve for controlling the flow of air from the air chamber into the container;
• a compressible liquid pump chamber located in the housing;
• a liquid inlet valve secured to the seat member for allowing liquid to flow from the container into the compressible pump chamber;
• and
• a liquid outlet valve located downstream of the pump chamber.