FIG. 1 is an exemplary prior art refillable manual dispenser, generally indicated by the numeral 10. Dispenser 10 includes a housing 12 which is wall mounted. Located within the housing 12 is a refill unit (not shown) that may be filled with soap. The housing 12 is hinged to a mounting base 14 and has an open position to permit inserting and removing refill units (not shown) the dispenser and a closed and/or locked position for operation.
The housing 12 is also provided with a bar/actuator 16 wherein a user pushes or pulls the bar in order to discharge a predetermined quantity of fluid from the nozzle. A push-type dispenser is illustrated, however, hands-free dispenser are also generally known.
The housing 12 includes a window 17 which allows a person to view the fluid level of the replaceable container. In such a system, the refill unit is replaced when a custodian notices that the refill unit is empty or near empty. Some prior art dispensers have a display that displays an amount of dispenses left in the refill unit, or turns on an indication light when the level is determined to be low.
These prior art dispensers assume a set number of dispenses per refill unit and when a new refill unit is installed, the predetermined number is displayed on the display and is decremented each time a dose of product is dispensed. In some embodiments, when a predetermined number of dispenses has occurred, an indication light is energized. Thus, if the preselected number is 100, the dispenser indicates the refill unit is empty after 100 dispenses. However, the actual number of dispenses a refill holds is not typically consistent. There are internal factors that cause variance in the number of dispenses from one refill unit to another, such as, for example, priming issues with a pump, partial dose sizes, short stroking a pump, temporary clogs, partial actuations of an actuator, and the like. There may be some variances between dispensers as well and some variances due to environmental factors. In addition, the preselected number may be selected to ensure that the refill unit is not empty prior to the preselected number being reached, thereby ensuring that there is a significant volume of product left in the refill unit when the indicator indicates that it is empty. In sum, when the prior art dispensers indicate the dispenser is empty or close to empty, it may not be empty or close to empty.