Pressure-compensated liquid dispenser

摘要

An automatic soap dispenser (10) includes a disposable soap container including a dispensing mechanism (20) in which walls of an interior chamber (56) cooperate with a diaphragm (62) and a plunger (66) to form a transit chamber (64), which is resiliently expandable against the force of a spring (80). When a solenoid (58) permits the diaphragm (62) to move away from the outlet of a passage (50) in a flow path from the interior of a pressurized reservoir (18) to the expandable transit chamber (64), travel of the plunger (66) permits the transit chamber (64)'s pressure-relieving outlet opening to expand so that the pressure within the transit chamber (64) is determined predominantly by the force of the spring (80) rather than by the pressure within the reservoir (18). The velocity of the liquid dispensed from the transit chamber (64) through the dispensing mechanism's spout (16) is therefore relatively independent of the pressure within the reservoir (18).