Abstract:
A foaming soap dispenser includes a housing having a discharge opening at the bottom, a receptacle in which a liquid soap reservoir can be replaceably inserted and a soap container beneath the reservoir. A peristaltic or squeezed-tube pump for the soap and a diaphragm pump for feeding foaming air to a foaming device disposed close to the discharge opening, can be driven separately electrically.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This is a continuation, under 35 U.S.C. §120, of copending International Application No. PCT/AT2009/000149, filed Apr. 15, 2009, which designated the United States; the prior application is herewith incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to a foaming soap dispenser having a housing with a dispensing opening on the underside, a receptacle inside the housing, a liquid soap reservoir to be exchangeably inserted into the receptacle, an intermediate container underneath the reservoir, a metering pump for supplying the soap, an air pump for supplying foaming air, and a foaming device close to the dispensing opening. 
     Foaming soap dispensers having separate pumps for air and soap are already known, for example from International Publication No. WO 96/29921, in which two piston pumps can be actuated together through the use of an actuating element which is formed by a pivotable lid of the housing. 
     For the sake of simplicity, reference is made herein and in the appended claims to “foaming soap” and “soap,” which are understood to include all foamable substances for cleaning, disinfection, care, etc. 
     SUMMARY OF THE INVENTION 
     It is accordingly an object of the invention to provide a foaming soap dispenser, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and which can be actuated in a contactless manner. 
     With the foregoing and other objects in view there is provided, in accordance with the invention, a foaming soap dispenser, comprising a housing having an underside accommodating a dispensing opening, a receptacle disposed inside the housing, a liquid soap reservoir exchangeably inserted into the receptacle, a soap container disposed underneath the reservoir, a peristaltic metering pump for supplying soap, a diaphragm air pump for supplying foaming air, and a foaming device in vicinity of the dispensing opening. 
     A diaphragm pump is a machine for delivering liquids or gases. Its operational principle is similar to that of a piston pump, but the medium to be delivered is separated from the drive by a diaphragm. The separating diaphragm thus shields the mechanical part of the drive from harmful effects of the delivery medium. The drive is effected, for example, by an electric motor through the use of a connecting rod fastened to the diaphragm. Such diaphragm pumps are obtainable in a small size as so-called micropumps, which are disposed, for example, in a compact L-shaped housing, in which an outlet and an inlet are oriented parallel to one another and to a motor axis. 
     A peristaltic or squeezed-tube pump is more suitable for viscous substances, such as soap, for example, since a peristaltic pump is insensitive to air inclusions and ensures that the appropriate portion of soap is dispensed. A pump rotor carries at least two rollers, which protrude from the circumference or periphery and squeeze a tube which is curved around the circumference of the rotor. The drive is in particular likewise effected by an electric motor. 
     In order to provide contactless dispensing, the foaming soap dispenser is preferably provided with a sensor device in the vicinity of the dispensing opening. The sensor device is used to detect a hand held under the opening and to put the two pumps for generating a portion of foamed soap into operation. 
     A preferred embodiment provides that the container, the two pumps including the electric motors, the foaming device and preferably a controller are combined in a working block which is provided as a compact component in the lower region of the dispenser housing. The working block includes a molded part which is preferably produced from plastics material and has an upper and a lower recess. The soap container is provided in the upper recess and the two pumps and the foaming device are inserted into the lower recess. In this case, a preferred embodiment provides that the foaming device is held in the working block through the use of a clip or similar plug-in configuration in such a way that it can be exchanged easily in order, for instance, to ensure that foaming devices having different screen inserts or foaming bodies can be used as required. 
     In a further preferred embodiment, it is provided that the ratio of the delivery volumes of air and soap can be set through the use of the controller by changing the speed of one of the two electric motors. For this reason, DC motors are used in particular, having a speed and a delivery amount connected directly therewith which is directly proportional to the motor voltage. 
     Changing the foam consistency makes it possible, on one hand, to set a fixed minimum dispensing amount, for example of a disinfecting cleaning fluid or, on the other hand, to make available, in the event of heavy soiling, a larger amount or, in the event of light soiling, a smaller amount of soap foam, and in the process to leave the dispensed portion and dispensing time virtually unchanged in each case. 
     In a preferred embodiment, it is therefore provided that the volume ratio can be set by changing the speed of the motor for the soap pump. The speed of the motor for the air pump thus remains constant in this embodiment. Preferred volume ratios of air to soap are between 50:1—fairly dry, ultrafine-pored foam—to 50:2 (=25:1), i.e. with twice the proportion of soap, as a result of which the foam is fairly fluid. Preferred dispensing amounts of foamed cleaning fluid are from approximately 0.3 ml for 1 second and an approximate volume ratio of 50:1—fairly dry foam—to approximately 0.9 ml for 1.5 seconds and an approximate volume ratio of 50:2—very moist foam. The delivery volume of the air pump can preferably be 15 ml/sec. 
     Other features which are considered as characteristic for the invention are set forth in the appended claims. 
     Although the invention is illustrated and described herein as embodied in a foaming soap dispenser, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
     The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  is a diagrammatic, front-perspective view of a foaming soap dispenser according to the invention with a cover removed; 
         FIG. 2  is a schematic operational illustration of a working block according to the invention; 
         FIGS. 3 and 4  are respective sectional views of a diaphragm pump and a peristaltic pump; 
         FIG. 5  is a bottom-perspective view of the working block; and 
         FIG. 6  is a schematic diagram of a circuit for stabilizing voltage output by batteries. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the figures of the drawings in detail and first, particularly, to  FIG. 1  thereof, there is seen a foaming soap dispenser with a housing  21  having a cover, in which it is possible to insert a reservoir  23  in an exchangeable manner into a fluid-tight receptacle  20  in an upper region of the housing. A dispensing opening  9 , which is shown in  FIG. 5 , is disposed at the underside of the housing  21 . All of the elements necessary for operation are combined in a compact working block  1  provided in a lower region. As is illustrated schematically in  FIG. 2 , the working block  1  contains a soap container  2 , from which a soap pump  5 , which is configured as a peristaltic or squeezed-tube pump, draws soap and supplies it through a soap line  4  to a foaming device  3 . 
     The working block  1  furthermore contains an air pump  7 , which is configured as a diaphragm pump, that draws in air and supplies it through an air line  6  likewise to the foaming device  3 . An actuating device  8  makes it possible to change various parameters, such as a size of a foam portion  10 , an air-soap ratio, etc. 
     The pumps  5 ,  7  each have an electric drive, in particular a DC motor, the speed of which is directly proportional to the motor voltage. As is shown in  FIG. 3 , the pump  7  has an eccentric disk  12  which is fastened to a motor output shaft  11  and moves a spring-loaded reciprocating piston  13  back and forth. The reciprocating piston  13  projects into a pump housing and is connected to a diaphragm  14  which is braced between two housing parts and bounds a pump chamber  17 . The pump chamber  17  has an inlet  15  and an outlet  19 , to each of which a respective nonreturn valve  16  and  18  is assigned.  FIG. 3  shows a pressing-out or pressure position of the air pump  7 , in which the inlet-side valve  16  is closed and the outlet-side valve  18  is open. 
     The working block  1  furthermore contains the peristaltic soap pump  5 , which is illustrated diagrammatically in  FIG. 4 . The pump includes an output shaft  25 , a rotor  26  fastened to the output shaft  25  and two or three rollers or rolling bodies  27  on the rotor  26  which protrude around the circumference and are mounted in a rotatable manner. A tube  28 , which is disposed approximately in a semicircle around the rotor  26 , is squeezed by the rollers  27  as the rotor  26  rotates in such a way that soap contained in the tube  28  is delivered from an inlet  29  to an outlet  30 . A peristaltic pump  5  of this kind is self-priming and its delivery action is not adversely affected by included air so that it is readily suitable for the uniform metering of soap portions. 
       FIG. 5  shows a view obliquely from below into the working block  1 . The working block has a molded part produced from plastics material. The soap container  2 , which is provided on the top side of the molded part, is closed by a lid that supports the receptacle  20 . Recesses for the air pump  7 , the soap pump  5 , the foaming device  3  and a non-illustrated controller board, are provided on the underside. Respective tubes lead to the foaming device  3  from the outlet  19  of the air pump  7  and the outlet  30  of the soap pump  5 , namely an air duct having reference numeral  6  and a soap duct having reference numeral  4 . The inlet  29  of the soap pump  5  is connected by a further tube  31  to the top-side soap container  2 . The foaming device  3  is provided in an exchangeable manner on the working block  1  by way of a U-shaped stirrup  32  and has the dispensing opening  9  at the underside of the housing. 
     The amount of air delivered is kept constant, that is to say that the speed of the air pump  7  is not changed. The soap proportion, which affects the consistency of the foam, can be varied by changing the speed of the soap pump  5 . 
       FIG. 2  shows the speed regulation of the soap pump  5  as being from outside the housing  1 . However, a rotary knob of the actuating device  8 , which is in the form of a potentiometer, can also be disposed inside the housing, as is indicated in  FIG. 1 , in which case a housing lid, which may be locked, has to be opened. This embodiment allows only authorized users, for example service staff, to change the foaming soap consistency. 
     The dispenser may be connected to the local power supply or have an internal power source. In the case of an internal power source, for example four alkaline batteries, the battery voltage drops from 6.4 V to 4 V with continuing use. Thus, an internal power source is therefore assigned in particular voltage stabilization through the use of pulse-width modulation, as shown in  FIG. 6 , and use is made of DC motors, the motor voltage of which is located close to the lower limit of the battery voltage so that the specified speeds of the two pumps  5 ,  7  can be maintained almost until the internal power source is used up. As is shown in  FIG. 6 , a controller μC compares a supply voltage to a reference voltage U REF  of a reference diode, which may also be an internal reference, and regulates the pulse-width modulation (PWM) of a motor M to 4 V. An output transistor T 1  serves as a driver in order to achieve the necessary current for the motor.