Foam-at-a-distance systems and anti-drip mechanisms for such systems

A foam-at-a-distance system comprising:

• a spout located at an upper position and configured to dispense fluid on a user's hand;
• a foam generator having a suck-back mechanism located proximate an end of the spout;
• a liquid pump portion;
• a container located below the spout in fluid communication with the liquid pump portion;
• an air pump portion in fluid communication with ambient air;
• a liquid conduit extending upward from the liquid pump portion to a liquid inlet in the foam generator;
• an air conduit extending form the air pump portion upward to an air inlet in the foam generator;
• the foam generator having a housing;
• the housing having a first portion with a first inside bore and a second portion with a second inside bore, wherein the first inside bore has a smaller diameter than the second inside bore;
• a piston having a first seal in contact with the first inside bore;
• a second seal extending from the piston and in contact with the second inside bore;
• wherein the second seal prevents air from flowing between the second seal and the second inside bore;
• a first mixing chamber located downstream of the first seal and upstream of the second seal;
• the liquid inlet located upstream of the first seal;
• the air inlet located downstream of the first seal and upstream of the second seal;
• a second mixing chamber located in the second inside bore;
• wherein movement of the second seal in an upstream direction provides negative pressure in the second mixing chamber and draws in fluid from the outlet.

A foam dispensing system comprising:

• a spout configured for dispensing fluid onto a user's hand;
• a container located below the spout;
• a foam generator located within the spout;
• a liquid pump chamber;
• an air pump chamber;
• a liquid conduit extending upward to a liquid inlet in the foam generator;
• an air conduit extending upward to an air inlet in the foam generator;
• a piston;
• the piston moving between a first position and a second position;
• wherein liquid flowing in through the liquid inlet moves the piston in a first direction;
• wherein a biasing member moves the piston in a second direction that is substantially opposite the first direction;
• a first piston seal, wherein the first piston seal allows liquid to flow past the first piston seal;
• wherein the liquid inlet is located upstream of the first piston seal;
• wherein the air inlet is located downstream of the first piston seal;
• a second piston seal located downstream of the air inlet;
• wherein the second piston seal forms a seal between an inside bore and the piston and wherein air is prevented by the second piston seal from flowing between the second piston seal;
• a mixing chamber;
• wherein movement of the second piston seal in a downstream direction decreases the mixing chamber volume and movement of the second piston seal in an upstream direction increases the volume of the mixing chamber and draws in fluid from the outlet.