The use of soap dispensers for hand washing has now become widely known and accepted. Typically, such soap dispensers dispense a quantity of soap which is then worked into a lather by the user when combined with water on the hands. Recently, there has been a general acceptance of foam soap delivery systems. In such systems, liquid soap is combined with air, typically under force or pressure, and then driven through a mesh, screen or porous passage to finish or homogenize the soap into a uniform stable composition. In some systems, a mixing chamber is employed prior to the porous structure or passage in order to prepare a prefoam of randomly sized and spaced bubbles. The mixing chamber and porous passage are generally presented at a foamer head that is immediately adjacent the drive mechanism for the liquid and air. In general, these drive systems are typically pistons within cylinders or pumps to achieve the pressurization and drive of the liquid soap and air.
In the past, little attention has been given to the development of foamer heads that are adaptable for use in systems where the liquid soap source is remote from the dispensing head. Indeed, the prior art foamer heads have typically been of a rudimentary nature, with little regard for the specifics of the design or the configuration of the constituent elements. While the prior art foamer heads have generally been of a satisfactory nature, little attention has been given to the efficacy of soap foam generation to achieve a desired uniformity and integrity of the resulting foam. Moreover, where foam soap is to be dispensed from an area remote from the liquid soap source, the prior art has generally taught the generation of the foam close to the liquid soap source, with its subsequent delivery to a dispensing head remote from that source. However, such systems have generally proven to be problematic. It has been found that foam is difficult to drive for any distance through a conduit. Breakdown of the foam occurs, resulting in reduced volumes of soap being dispensed on each dispensing cycle, and with the ultimate dispensing of liquid soap globules. It has also been found that such remote delivery systems have resulted in extremely low output volumes on subsequent dispensing operations, and even total failures to dispense when the period of time between dispensing operations has been sufficient to allow the soap foam within the conduit to fully breakdown. Other problems have been evidenced with a “wet” foam output on subsequent dispensing operations, resulting from the breakdown of foam in the conduit into a liquid form.
In systems where the dispensing head is remote from the point of foam generation, it has been found that the liquid and/or air cylinders of this system have required careful design to ensure sufficient “suck-back” force on the return stroke of the dispensing operation to draw residual foam back away from the dispensing head to preclude drips and the like.
The remote dispensing heads referenced herein are typically present in what are referred to as counter-mount systems, in which the soap reservoir is maintained beneath the counter and the dispensing head is above the counter, the two being interconnected by conduits that are three or more feet in length. The problems of foam breakdown and suck-back failure are characteristic of such systems.
There is a need in the art for an improved soap foam generator, adaptable for use in any of a variety of delivery systems, and particularly in remote dispensing systems, such as counter-mount systems, in which the air and liquid sources are remote from the dispensing head.