Sequentially activated multi-diaphragm foam pumps, refill units and dispenser systems

A foam pump comprising:

• a housing;
• a molded multi-chamber diaphragm;
• the molded multi-chamber diaphragm comprising:
• a liquid pump chamber;
• and
• two or more air pump chambers;
• wherein the two or more air pump chambers are each configured to hold a first volume of air;
• wherein the liquid pump chamber is configured to hold a second volume of foamable liquid;
• wherein the first volume of air is greater than the second volume of foamable liquid;
• a foamable liquid inlet valve;
• two or more air inlet valves;
• one or more outlet valves;
• a mixing chamber downstream of the one or more outlet valves for mixing foamable liquid from the liquid pump chamber with air from each of the air pump chambers;
• wherein the liquid pump chamber has a liquid pump chamber stem and the two or more air pump chambers each have an air pump chamber stem;
• and
• wherein the liquid pump chamber stem has a different length then each of the air pump chamber stems.

A foam pump comprising:

• a housing;
• a molded multi-chamber diaphragm;
• the molded multi-chamber diaphragm comprising:
• a liquid pump chamber;
• and
• two or more air pump chambers;
• a liquid inlet;
• the liquid inlet having a first diameter;
• a flow restrictor in fluid communication with the liquid inlet;
• the flow restrictor having one or more orifices therein;
• the one or more orifices restricting the liquid flow from the liquid inlet to the liquid pump chamber;
• wherein during operation the liquid pump chamber and two or more air pump chambers are compressed and expanded sequentially to pump liquid and air;
• and
• wherein the restricted liquid flow causes the volume of liquid that enters liquid pump chamber as it expands to be less than the volume of liquid that would enter the liquid pump chamber if the flow restrictor is removed.