A foam dispenser includes a housing, a drive motor, and a foam pump. The foam pump includes a pump housing, and a molded multi-chamber diaphragm. The molded multi-chamber diaphragm includes a liquid pump diaphragm having a liquid pump stem and two or more air pump chambers each having an air pump stem. The length of the liquid pump stem is longer than the air pump stem. The foam pump further includes one or more outlet valves, a mixing chamber, an outlet for dispensing foam wherein the outlet is in fluid communication with the foam cartridge; and an actuator for sequentially actuating the liquid pump chamber and the two or more air pump chambers, wherein there is lost motion between the actuator and the liquid pump diaphragm.

A viscous fluid is dispensed precisely using a fluid pump, control valves configured to control both the air inlet and outlet of the fluid pump, an optional adjustable regulator further controlling the air outlet, and a control circuit that opens and closes the control valves. To further increase the precision, additional control valves can be used to control liquid inlet and outlet of the fluid pump.

A viscous fluid is dispensed precisely using a fluid pump, control valves configured to control both the air inlet and outlet of the fluid pump, an optional adjustable regulator further controlling the air outlet, and a control circuit that opens and closes the control valves. To further increase the precision, additional control valves can be used to control liquid inlet and outlet of the fluid pump.

An exemplary foam dispenser includes a housing, a drive motor and a foam pump operatively coupled to the drive motor. The foam pump is secured to the housing and the foam pump includes a housing and a molded multi-chamber diaphragm. The molded multi-chamber diaphragm includes a liquid pump chamber, two or more air pump chambers; and an outlet valve. A mixing chamber is included and located downstream of the outlet valve for mixing foamable liquid from the liquid pump diaphragm with air from each of the two or more air pump chambers. In addition, a foam cartridge and an outlet for dispensing foam are also included.

Exemplary embodiments of high non-aerosol foam sanitizers are disclosed herein. An exemplary embodiment of high non-aerosol foam sanitizer includes a liquid mixture that includes an alcohol, water and a surfactant mixed with and entrapping air to form a plurality of foam bubbles. Wherein more than about 50 percent of the foam bubbles have a size of between about 50 μm and about 250 μm.

A foam pump has dual, coaxial air and liquid cylinders, each having a respective air and liquid piston which move together during a dispensing operation. One or more air passageways between the air cylinder and a liquid-air mixing chamber are configured to impart rotation to an airstream passing from the air cylinder to the mixing chamber to increase turbulent mixing of the air and liquid in the mixing chamber. The liquid cylinder is axially aligned with the air cylinder to provide a low profile pump which does not require a dip tube or sleeve to communicate with the bottom of the liquid source when used in an inverted application wherein the foam pump is positioned below the source of liquid. A resilient valve member in the liquid outlet is biased to close on its own to prevent leaking in the event the air and liquid pistons do not fully return to the home position.

A foam pump has dual, coaxial air and liquid cylinders, each having a respective air and liquid piston which move together during a dispensing operation. One or more air passageways between the air cylinder and a liquid-air mixing chamber are configured to impart rotation to an airstream passing from the air cylinder to the mixing chamber to increase turbulent mixing of the air and liquid in the mixing chamber. The liquid cylinder is axially aligned with the air cylinder to provide a low profile pump which does not require a dip tube or sleeve to communicate with the bottom of the liquid source when used in an inverted application wherein the foam pump is positioned below the source of liquid. A resilient valve member in the liquid outlet is biased to close on its own to prevent leaking in the event the air and liquid pistons do not fully return to the home position.

A valvular conduit, preferably a Tesla valvular conduit, in which a plug member is coaxially received within a bore in a sleeve member and in which passageways are defined between the plug member and the sleeve member within interior walls configured to permit mixing of fluid flowing through the passageways in at least one direction, preferably, the relatively free passage of fluid through the passageways upstream but increased the resistance to downstream flow of the fluid through each passageway.

A valvular conduit, preferably a Tesla valvular conduit, in which a plug member is coaxially received within a bore in a sleeve member and in which passageways are defined between the plug member and the sleeve member within interior walls configured to permit mixing of fluid flowing through the passageways in at least one direction, preferably, the relatively free passage of fluid through the passageways upstream but increased the resistance to downstream flow of the fluid through each passageway.

A system (16) for pumping a fluid, comprising: a pump (17) comprising a suction side (18) and a discharge side (19); a motor (20) for driving the pump, which motor is drivingly connected to the pump via a shaft (21); a return line (23) providing a feed-back conduit for the fluid from the discharge side to the suction side; a control valve (24) controlling the flow of the fluid through the return line; and a first sensor device (27) for monitoring a first system parameter which is a function of the differential pressure across the pump. The system further comprises: a second sensor device (28) for monitoring a second system parameter which is a function of the torque of the pump; and a control unit (25) arranged to: receive monitored first system parameter values from the first sensor device and, for each monitored first system parameter value, identify a minimum allowable second system parameter value; receive monitored second system parameter values from the second sensor device and, for each monitored second system parameter value, compare the monitored second system parameter value with the identified minimum allowable second parameter value; and regulate the control valve such that the monitored second parameter value does not fall below the minimum allowable second parameter value. A method of operating such a system is also disclosed.