Automatic fluid dispenser and method

An automatic dispenser for spraying a liquid or flowable disinfectant to dermatologically treat hands or the like. The dispenser automatically senses the presence of a user's hands using an infrared sensing mechanism, and in response sprays a predetermined volume of volatile disinfectant onto the user's hands for a predetermined length of time via a control circuit. The control circuit supplies an electromagnet with power for the predetermined length of time to move a magnetic frame downward against an inverted bottle of disinfectant in the dispenser housing. The bottle contains a known quantity of disinfectant fluid and the dispensing operation dispenses a measured dose upon each actuation. A counter circuit then counts the doses dispensed and provides a warning signal when the bottle is empty or nearly empty of the flowable disinfectant. The dispenser has a nozzle with a conically shaped outlet which is in fluid communication with the inside of the bottle via a short tube which extends from the bottle opening and fits tightly to the nozzle. The dispenser operates automatically and avoids the need for the user to physically touch it. The user's hands thereby can be completely disinfected without the risk of recontamination from contact with the dispenser or with hand driers since the disinfectant is volatile and quickly evaporates.

BACKGROUND OF THE INVENTION 
The present invention relates to a fluid spraying device for the 
dermatological treatment of hands, and more particularly to a disinfectant 
dispenser, and to the construction and operation thereof. 
In the past, dispensers have been used to dispense powdered or atomized 
liquids for use on different parts of the human body, such as the face or 
limbs. Most previous dispensers for dispensing various liquids for medical 
or disinfectant purposes have been designed such that the user must 
physically contact the dispenser. For hygienic reasons, this presents a 
problem since the dispenser can become contaminated and aid in the spread 
of diseases to the users thereof. Prior devices have only been of moderate 
success, even those specifically designed for medical or commercial 
applications. Many disadvantages have been experienced with such devices, 
such as clogging thereof, a structure which is complicated to build, 
maintain and service, and the requirement that the dispenser it must be 
contacted to be used. Moreover, most previous automatic devices also 
suffer from complicated mechanisms, unreliable warning systems for 
indicating that the container or reservoir is empty and inefficient 
dispensing of the fluids. 
An effective method of applying a liquid or flowable disinfectant is by 
spraying it. This ensures the penetration of the fluid droplets into the 
skin. Spraying also optimizes hygienic conditions because no build-up or 
deposits of the disinfectant are produced on the dispenser. Thus, devices 
required for collecting and cleaning leftover particles or droplets are 
unnecessary. Spraying also eliminates the need for hand driers, which are 
easily and often contaminated. When volatile disinfectants are used, all 
that is required is that the user's hands be rubbed together to properly 
spread the disinfectant and irrigate the palms and the backs of the hands. 
Both hands can thereby be completely disinfected without contacting any 
surfaces. With many prior devices, the above-mentioned problems are caused 
by the fact that the disinfectants are often just sprinkled onto the hands 
and not sprayed thereon. Irrigation of the hands of the user is more 
likely to be concentrated on the backs of the hands instead of the palms 
which require the most irrigation. 
Another disadvantage of some prior devices is that they have significant 
operating inertia. A significant time interval is required before the next 
dispensing cycle can begin. These shortcomings impose limitations on the 
practical use of these devices in hospitals and other places where they 
must be used continuously by a large number of people. Moreover, the prior 
devices are relatively complex, expensive and bulky, and many require a 
built-in battery pack. Accordingly, these devices are unsuitable for a 
wide variety of uses, especially where hygiene is critical. 
FIG. 1 illustrates the general operation of a conventional spray bottle 15 
A pressurized gas is contained in the bottle 15 along with the material to 
be sprayed. A piece of soft plastic tubing 16 is disposed along 
substantially the entire height of the bottle 15. The tubing 16 carries 
the material, such as liquid L, from the bottle 15 to outlet tubing 17 and 
then through push button 18. Application of a force F on push button 18 
causes a valve (not shown) to open, whereby the pressurized gas in the 
bottle 15 forces liquid L upward through tubes 16, 17 and out through a 
nozzle on the push button as spray S. This conventional bottle 15 
dispenses liquid L primarily from the bottom of the bottle upward through 
the tubes 16, 17, and relies on the pressurized gas to force the liquid L 
in a direction opposite the natural gravitational pull. Another 
disadvantage of many conventional bottles is that the liquid cannot be 
completely dispensed from them. Because the bottles 15 are used in an 
upright position and the end of the tubing 16 which is disposed inside the 
bottle 15 cannot reach all of the liquid, some liquid is not used and thus 
is wasted. Yet another problem is that the user must touch the bottle 15 
to spray the liquid L, and in sterile environments where the liquid used 
is a disinfectant, contact with the bottle can contaminate the user's 
hands. 
The following patents exemplify known automatic fluid dispensers. These 
patents and any other patents or publications mentioned anywhere in this 
disclosure are hereby incorporated by reference in their entireties, 
U.S. Pat. No. 4,946,070 to Albert et al. discloses a surgical soap 
dispenser which dispenses soap from a flexible pouch. The pouch is 
contained in a housing and has an elongated dispensing leg which extends 
through a pumping mechanism. When the user's hands are detected in a 
triggering field by a light emitting diode (LED) and a light sensor, a DC 
motor is actuated to drive a gearing system coupled to a shaft on which 
the pumping mechanism is rotatably mounted. The pumping mechanism includes 
a roller which moves against the dispensing leg along a base pad and 
causes the soap in the dispensing leg to be dispensed through a pressure 
responsive valve. The path of the roller is configured to dispense one 
metered dose of soap per actuation of the motor. 
U.S. Pat. No. 4,722,372 to Hoffman et al. discloses an electrically 
operated dispensing device in which a disposable container of flowable 
material includes a deformable extension for containing a predetermined 
quantity of material. The container is retained in a housing which has a 
dispensing mechanism through which the extension is placed. The dispensing 
mechanism is actuated by a photocell system which detects the proximity of 
the user's hands or other object to be cleaned. The mechanism moves a 
lever arm to pinch the deformable extension and dispense the material 
through a check valve when the pressure in the extension is sufficiently 
high. 
U.S. Pat. No. 4,670,010 to Dragone discloses a liquid-nebulizing device for 
spraying a disinfectant on the hands of the user. The device includes a 
liquid reservoir and a dispensing mechanism. The dispensing mechanism 
includes a spray nozzle and pumping unit which delivers liquid to the 
nozzle. A system of conduits connects the reservoir and pumping unit in 
series, and the pumping unit to the spray nozzle. A solenoid valve of the 
pumping unit allows liquid to freely flow to the reservoir when the valve 
is open, but keeps the liquid in the delivery conduit when the valve is 
closed. A sensor detects the presence of hands in the upper cavity, starts 
the pump and closes the solenoid valve. Upon activation of the pump, the 
liquid in the delivery conduit is forced out through the nozzle in a 
spray. A warning system senses the amount of liquid in the reservoir and 
signals a user to refill it. 
U.S. Pat. No. 4,645,094 to Acklin et at. discloses a photo-electric 
controlled dispenser housing a flexible container with a dispensing 
extension. The housing is equipped with a pinch valve and a means to 
squeeze the container. An infrared proximity sensor actuates the 
mechanism, and the dispensing time period is regulated by controlling the 
time that the valve remains open. A warning system senses the amount of 
liquid in the container by the angle of the squeezing means. 
U.S. Pat. No. 3,650,435 to Kleefeld discloses an SCR circuit for use with a 
photoelectric controlled dispenser. The circuit supplies current to a pump 
to dispense the liquid. The pump is turned off by interrupting the SCR 
current by mechanical means or a timing switch. 
U.S. Pat. No. 3,273,752 to Horeczky discloses a photo-electric controlled 
dispenser which dispenses flowable material that is not pressurized. The 
dispenser has a housing which retains a container in an upside down 
orientation with the outlet thereof pointed downward. The container has a 
magnetic pellet inside the neck which normally closes off the opening of 
the container. A photocell detects the presence of the user's hands and 
triggers a timer circuit. The timer circuit in turn energizes an 
electromagnet in the housing which is adjacent the neck of the container. 
When the electromagnet is energized the pellet in the container is pulled 
from its resting position toward the wall of the container adjacent the 
electromagnet thereby enabling flowable material to be dispensed. The 
timing circuit controls the length of time the pellet is held by the 
electromagnet. Only a fixed amount or dose is dispensed with each 
dispensing cycle. 
Accordingly, there exists a need for an automatic dispenser for dispensing 
fluids in measured doses which does not require a user to contact the 
dispenser or any other equipment such as a drier. In particular, a simply 
constructed, reliable dispenser is needed for sterile environments to 
dispense volatile disinfectants with a fine spray action. 
SUMMARY OF THE INVENTION 
The objects and advantages of this invention are achieved by a fully 
automated spraying device for dispensing flowable materials, and 
particularly a volatile disinfectant to dermatologically treat the user's 
hands. Examples of other flowable materials which may be dispensed are 
liquid soaps, lotions, liquid-solid slurries and fluidized powders, but 
the invention is particularly suited for dispensing sprayable materials. A 
technical problem to be solved by this invention is to provide a fully 
automated dispenser that sprays fluids to quickly and efficiently irrigate 
both hands of the user. The present fully automated dispenser includes a 
housing having two chambers. One chamber contains two power sources, a 
control circuit, a counter circuit and a solid state relay. The other 
chamber contains a spray bottle filled with disinfectant and a pressurized 
gas, an electromagnet, a magnetic frame and an infrared light sensor which 
is located at the bottom of the dispenser. The spray bottle is installed 
upside-down with the magnetic frame on top of the bottle. 
A power source connected to a first power converter continuously supplies 
power to the infrared sensor, the control circuit, the solid state relay 
and a counter circuit. Upon introduction of the user's hands underneath 
the dispenser, the infrared sensor senses the presence of the hands and 
activates the control circuit. The control circuit in turn actuates the 
solid state relay for a predetermined length of time so that the switch in 
the relay remains closed for the reset delay. During the time the switch 
in the relay is closed, a second power source connected to a second power 
converter energizes the electromagnet to magnetically draw the magnetic 
frame downward and thereby press down on the spray bottle. A spray nozzle 
operatively connected to the bottle dispenses volatile fluid disinfectant 
onto the hands of the user with this pressing down motion. The volume of 
disinfectant dispensed is a function of the length of time the bottle is 
depressed. Therefore, the timing unit in the control circuit can be set to 
provide dispensing action to dispense an optimal amount of disinfectant. 
Moreover, the time interval between successive dispensing cycles is 
negligible, such that continuous use of the dispenser is possible. 
The control circuit actuates the counter circuit simultaneously with the 
actuation of the solid state relay. The counter circuit is initially set 
to a predetermined value and counts down each time it is actuated. As the 
counter approaches zero, this indicates that the spray bottle will be 
nearly empty, because each spray bottle of this invention contains exactly 
the same volume of fluid and an exact amount of pressurized gas. A timing 
unit in the control circuit is preset to provide the downward push on the 
frame for a predetermined time thus ensuring that a predetermined volume 
of fluid is dispensed each time. The total number of pushes needed for 
emptying the spray bottle can be experimentally determined. When the value 
in the counter circuit is zero (or close to zero), the counter circuit 
actuates a buzzer (or light or other signal) to notify the user or 
attendant. The buzzer can be continuously sounded until a new spray bottle 
is installed and the counter circuit reset. On no parts of the dispenser 
is disinfectant deposited which would necessitate cleaning thereof. 
The spray nozzle of this invention is generally conical in shape having an 
upper portion and a lower portion. The upper portion is cylindrical and 
has internal threads which mate with outside threads of a preferably hard 
plastic tubing extending outwardly from the spray bottle opening. The 
threaded connection between the nozzle and the tubing prevents leakage. 
The lower portion of the nozzle is a conically shaped opening or hole 
wherein the upper diameter of the conical opening is equal to the diameter 
of the upper portion of the nozzle, that is, the diameter of the 
cylindrical portion. The diameter of the bottom of the conical opening, 
which is the outlet of the nozzle, is substantially smaller than the upper 
diameter of the opening. This enables the fluid to be sprayed in fine 
droplets and therefore over a wide area. The volatile fluid is atomized 
and sprayed evenly on the hands to be irrigated to ensure efficient 
dermatological treatment thereof. A hand drier is thus unnecessary with 
the present invention because once the sprayed volatile fluid irrigates 
the hands it quickly evaporates. 
These and other features and advantages of the invention may be more 
completely understood from the following detailed description of the 
preferred embodiments of the invention with reference to the accompanying 
drawings.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
With reference to the drawings wherein like numerals indicate like 
elements, FIG. 2 discloses a dispenser shown generally at 20 according to 
the present invention. Dispenser 20 comprises a housing having chambers 21 
and 22. In chamber 21, two power sources 24 and 26, a control circuit 28, 
a counter circuit 30, and a solid state relay 32 are installed. A 
simplified circuit diagram is shown in FIG. 10. In chamber 22, spray 
bottle 36 is placed inverted with spray nozzle or outlet 40 adjacent the 
bottom opening 42 of the dispenser 20. Spray bottle 36 is retained in a 
vertical position by cap 44, which is fixed to reciprocating magnetic 
frame 46. Frame 46 has four holes, one at each comer thereof. 
Corresponding rods or pins 48 are attached to and extend from dispenser 
20. The rods 48 are movably positioned in the holes so that frame 46 can 
move freely in a vertical direction guided by rods 48. The bottom of frame 
46 rests on the bottom of spray bottle 36. While the maximum gap between 
the top part of frame 46 and the top part of electromagnet 50 is 
preferably three millimeters, the gap between the bottom part of 
electromagnet 50 and the bottom part of frame 46 is preferably not less 
than six centimeters. The frame 46 is made of a magnetic material such as 
steel which is attracted by a magnetic force. Spring 52, located at the 
bottom of chamber 22, also helps maintain the spray bottle 36 and spray 
nozzle 40 in place by biasing the spray bottle against frame 46. A 
relatively short piece of plastic tubing 54 provides fluid communication 
between the inside of spray bottle 36 and spray nozzle 40. As shown in 
FIG. 4, electromagnet 50 is fixed in dispenser 20 near the top thereof by 
rods 56, which may or may not be of a magnetic material. A proximity 
sensor 60 is preferably positioned adjacent the bottom of dispenser 20 and 
is preferably located toward the back of the dispenser 20 as shown in FIG. 
3. The proximity sensor 60 can be any known sensing mechanism, as 
discussed in detail later, and preferably is an infrared sensor. 
A dispenser made in accordance with the present invention advantageously 
does not require a soft plastic tubing, such as tubing 16 used in the 
conventional design shown in FIG. 1. Thus, the structure of the dispenser 
20 is simplified. Moreover, the dispenser 20 positions the bottle 36 in an 
inverted manner, and thereby utilizes gravity to ensure that all of the 
liquid in the bottle is dispensed. All that is required to carry the 
liquid to the nozzle 40 is a short piece of tubing 54. 
Referring to FIGS. 7, 8A and 8B, the tubing 54 is preferably rigid, acts as 
a connector between the bottle opening 37 and the nozzle 40, and is 
tightly fitted to the nozzle 40. A normally closed valve 55 is provided in 
tubing 54 inside the bottle 36. When the spray bottle 36 is depressed by 
the downward movement of the magnetic frame 46, the bottle opening 37 
moves downward along the tubing 54 thereby opening the normally closed 
valve 55 to allow the liquid to be dispensed from the bottle through the 
conically shaped hole 64 of nozzle 40. Tubing 54 has an externally 
threaded end 54a, as shown in FIG. 7, to mate with the internal threads 
62a of opening 62 in the upper portion of spray nozzle 40 shown in FIG. 5. 
Lower opening 64 in the lower portion of the spray nozzle 40 has a conical 
shape. The top of the lower opening 64 is of substantially the same 
diameter as the inner diameter of the tubing 54. The lower opening 64 
tapers so that the bottom thereof has a diameter that is substantially 
smaller than the diameter at the top thereof. The taper of the conical 
shape is gradual to provide a venturi effect; that is, the velocity of 
fluid through the cone of the spray nozzle 40 increases as it nears the 
opening an outlet. In addition, fluid flowing along the tapered wall of 
the cone-shaped opening 64 spreads over a broader area at the outlet than 
liquid through a cylindrical hole would. The direction of the fluid 
movement through the cone-shaped lower opening is shown by arrows 66 in 
FIG. 8B. 
As a result, fluid is sprayed out of dispenser 20 in fine droplets and over 
a broad area, as shown in FIG. 9 for example. Any leakage of fluid in an 
upward direction might result in leftover disinfectant in the dispenser 
20; this could necessitate undesirable cleaning of the fluid chamber. Such 
a problem is solved by this invention by the threaded connection of the 
tubing 54 to spray nozzle 40 as shown in FIG. 8. Although the preferred 
connection is by mating threads, any non-permanent leak-proof connection, 
including a snap-fit connection, is within the scope of the invention. 
FIGS. 8A and 8B schematically illustrate the valve 55 in the upper part of 
tubing 54. The valve 55 is a conventional normally closed valve widely 
used with spray bottles, and generally comprises a valve hole 70 in the 
wall of the tubing 54. The upper end of tubing 54 includes a relatively 
small plastic cylindrical cup 72 containing a spring 74. A rubber ring 76 
fits tightly around tubing 54, is positioned directly beneath cup 72 and 
is held within a socket of plastic valve housing 78. The upper part of 
valve housing 78 is configured as a hollow tube 80 where fluid in the 
spray bottle 36 can flow as indicated by arrows 82. The lower part of the 
valve housing 78 forms an annular ridge extended and tightly fitted into 
the socket of a metal valve housing 86. The walls of plastic valve housing 
78 and metal valve housing 86 are directly adjacent one another with no 
gap between them. Tubing 54 pierces through and fits tightly within metal 
valve housing 86. An o-ring seal 88 keeps the spray bottle 36 sealed with 
respect to metal valve housing 86 such that there is no leakage of the 
fluid from the bottle takes place. In addition, spring 74 biases plastic 
valve housing 78 and rubber ring 76 against cup 72 and tubing 54 which 
also helps to prevent leakage. 
In the resting state as shown in FIG. 8A, the spray bottle 36 is filled 
with fluid under pressure. Spring 74 biases the upper part of the plastic 
valve housing 78 against cup 72 such that the bottom of the cup pushes 
rubber ring 76 to seal the lower end of the housing onto the lower part of 
metal housing 86. The rubber ring 76 is also sealed tightly around tubing 
54, and the valve hole 70 remains below the rubber ring. Once the 
dispensing cycle begins, the magnetic frame 46 presses down on the spray 
bottle 36 causing the bottle to move downward such that metal housing 86 
also moves downward along tubing 54 as shown in FIG. 8B. The plastic valve 
housing 78 in turn also moved down together with rubber ring 76. The 
tubing 54 which is fitted tightly within the upper cylindrical portion of 
the spray nozzle 40 remains fixed in place. Therefore, tubing 54 is 
depressed by spring 74 and is fixed to the nozzle 40. The rubber ring 76 
also moves downward the same amount as the bottle 36. The thickness of the 
ring 76 and the diameter of the valve hole 70 are selected so that the 
downward movement of the spray bottle 36 causes the ring 76 to be beneath 
the valve hole allowing the pressurized fluid in the bottle to flow 
through the valve hole into tubing 54 and subsequently out through spray 
nozzle 40 in atomized form as indicated by arrows 66. When the dispensing 
cycle is over, the spring 74 returns to its resting position and pushes 
the spray bottle 36 upward which results in the rubber ring 76 moving 
upward and returning to its resting position above the valve hole 70 as 
shown in FIG. 8A. Fluid thus stops flowing through valve hole 70 and one 
dispensing cycle is thereby complete. 
The preferred distance of downward travel of the bottle 36 is about three 
millimeters, which corresponds to the gap between the top part of frame 46 
and the top part of electromagnet 50 as shown in FIG. 2. The preferred 
thickness of ring 76 is about 1.5 millimeters, and the diameter of the 
valve hole 70 is preferably about 0.25 millimeter. 
Referring to FIG. 10, in the preferred embodiment of the invention, the 
dispenser 20 is equipped with integrated circuits (IC's) to control the 
dispensing operation. Two power sources input into two converters 24 and 
26, which are electrical devices that convert alternating current (AC) to 
direct current (DC). The converters 24 and 26 are each preferably composed 
mainly of a transformer and a rectifier. Since most IC's are designed to 
be used with 12 V DC, converter 24 is a step-down converter that converts 
an incoming 220 V AC to 12 V DC, and continuously powers the infrared 
sensor 60, control circuit 28, solid state relay 32 (which is a type of 
electronic switch) and counter circuit 30. Control circuit 28 is composed 
of a number of IC's including a timing unit, which is shown by reference 
numeral 29 in FIG. 10 and preferably comprises a conventional type of 
timing unit. The function of control circuit 28 is to control the 
dispensing process. The solid state relay 32 is a type of electronic 
switch. 
For ease of explanation a user's hands H are used to describe the operation 
of the dispenser 20. However, it will be understood that any part of a 
user's body, such as his arms or legs, or any implement placed such that 
the sensor 60 detects its presence can have the liquid dispensed upon it. 
In operation, when hands H are positioned under the dispenser 20 as shown 
in FIG. 9, the sensor 60 detects the presence thereof and actuates control 
circuit 28 by a signal, pulse or like method. Control circuit 28 turns on 
solid state relay 32; that is, the switch is closed. The timing unit 29 in 
control circuit 28 determines the length of time that the switch remains 
closed. When solid state relay 32 is turned on, that is, the switch is 
closed, converter 26 is connected to an incoming 220 V AC line. Converter 
26 is also a step-down converter and converts the incoming 220 V AC to 24 
V DC. The 24 V DC electrical current from converter 26 energizes the 
electromagnet 50 which magnetically draws the magnetic frame 46 downward. 
The electromagnet 50 was found to operate optimally with 24 V DC supplied 
to it for drawing the frame 46 downward. The frame 46 when drawn down in 
turn presses down on spray bottle 36, and valve 55 in tubing 54 within the 
bottle is thereby opened. With the valve 55 opened, the fluid disinfectant 
is forced out of the dispenser 20 through spray nozzle 40 and through 
opening 42. The volume of disinfectant dispensed can be made a function of 
the length of time the magnetic frame 46 is depressed. Since the 
electromagnet 50 continues to press the frame 46 down until the solid 
state relay 32 is turned off, i.e., the switch opened, the length of time 
the relay 32 remains "on" is determined by the delay of the timing unit 29 
in the control circuit 28. 
The time delay of the timing unit 29 in control circuit 28 can be adjusted 
to provide the optimal amount of disinfectant dispensed in each dispensing 
cycle. Once the relay 32 is turned off, the switch is opened and the 
circuit is ready to proceed through the entire dispensing cycle again when 
the sensor 60 is again tripped. Thus, there is only a negligible waiting 
period between dispensing cycles. An important feature of the present 
invention is that if additional disinfectant is to be dispensed, the 
sensor 60 must be actuated again. One dispensing cycle only dispenses a 
predetermined volume or dose of disinfectant during a predetermined length 
of time. Only after the hands H have been moved out of the detection zone 
of the sensor 60 and then repositioned into that zone does the cycle start 
over. In this way, disinfectant is not wasted since only one dose is 
dispensed each cycle. 
Once the disinfectant has been dispensed, rubbing the hands H together 
effectively disinfects the entire surface of the hands including the palms 
and backs thereof. The hands H once disinfected do not encounter the 
possibility of being reinfected or contaminated since there is no need to 
touch the dispenser 20. Use of a hand drier is also unnecessary since the 
dispensed fluid is volatile, and thus evaporates quickly. 
An additional aspect of the circuit shown in FIG. 10 is a warning feature 
to notify an attendant that the spray bottle 36 is empty, or nearly so. As 
described above, since the volume of disinfectant dispensed is fixed per 
dispensing cycle, and since spray bottles 36 used with the present 
invention hold the same amount of fluid and the same amount of pressurized 
gas, the number of dispensing cycles required to empty a bottle can be 
experimentally determined. This number is set in the counter circuit 30 of 
the circuit shown in FIG. 10. Each dispensing cycle dispenses one measured 
dose of disinfectant. For ease of explanation, the number of doses in a 
bottle 36 will be assumed to be 1200, and the counter circuit 30 will be 
preset to that number. Referring to FIG. 10, the counter circuit 30 is 
connected in series to control circuit 28, so that each time control 
circuit 28 actuates relay 32, it also actuates the counter circuit. Each 
time the counter circuit 30 is actuated, it counts down one unit. Counter 
circuit 30 includes an alarm device which is shown by reference numeral 31 
in FIG. 10 and may comprise a buzzer or a light, which is actuated when 
the "count" reaches zero. The alarm device 31 preferably emits a warning 
signal to notify an attendant that the bottle 36 is empty. The counter 
circuit 30 can alternatively be preset so that the alarm device 31 is 
actuated before the bottle 36 is completely empty. This would be done by 
setting the "count" in counter circuit 30 at a number less than the number 
of doses or dispensing cycles contained in a bottle 36. For example, if 
the bottle 36 contains 1200 doses, the counter circuit 30 could be set at 
1190, thus causing the alarm device 31 to actuate before the bottle is 
completely empty. When a new bottle is placed in the dispenser 20, the 
counter circuit 30 must be reset manually to the maximum number, in this 
case either 1200 or a smaller number. In general, most counter circuits of 
this type presently available are of the countdown type and start the 
buzzer when counting reaches zero. Generally any counter circuit, either a 
conventional or a modified one that can count down, accordingly can be 
used. The counter circuit 30 is preferably designed such that the warning 
sound continues until an attendant installs a full spray bottle 36 in 
chamber 22 and resets the counter circuit to the starting number thereof. 
Liquid delivered by the present dispenser 20 is atomized and spread over 
the hands H in as broad an area as possible in what may be called a spray 
zone. Preferably the hands H are about twenty centimeters away from the 
spray nozzle 40. The size of the spray zone can be varied by adjusting the 
proximity sensor 60 as described below. 
The proximity sensor 60 may be any of a variety of known sensor mechanisms. 
One embodiment of sensor 60 includes a light emitting source, such as an 
LED, and a light sensor or receiver, such as a phototransistor, placed 
near each other in a plane and generally directed to a common region, or 
detection zone. The light source emits light into the zone and any object 
that enters the zone reflects the light back to the light sensor. The 
sensor mechanism would be programmed so that when the light sensor detects 
the reflected light, it actuates the control circuit. When no object 
reflects light back to the sensor, the light emitted simply dissipates 
into the background. It will be clear to one skilled in the art that the 
size of the zone will be a function of the distance between the sensor and 
source, the intensity of light from the source and the angle of incidence 
of the emitted light. To make the zone larger, the distance between the 
sensor and source is increased and the angle of incidence of the emitted 
light made more horizontal, A higher intensity light source would also 
tend to make the zone larger. In contrast, to make the zone smaller, the 
distance between the sensor and the source would be decreased and the 
angle of incidence would be made more vertical. A lower intensity light 
source would tend to make the zone smaller. The detection zone is 
associated with the dispensing nozzle 40 and may be said to define a 
dispensing zone which generally corresponds to the detection zone. 
Another embodiment of sensor 60 positions the light source and light sensor 
so that the light emitted is always received by the sensor or receiver. In 
this configuration, the light emitted forms a beam which when broken by 
the insertion of a hand or other object into the detection zone, also 
interrupts the light sensor's reception of the light. When the light 
sensor no longer detects light, it actuates the control circuit to start 
operation of the dispensing apparatus, 
Yet another embodiment of sensor 60 includes a pair of light receiving 
members or sensors, such as photocells, located near each other in a 
plane. The sensors should be of approximately equal resistance and may be 
connected in a circuit such that one acts as a reference sensor and the 
other acts as a trigger sensor, for example, by connecting them in series 
with a reference junction between them. In operation, when no object is in 
the detection zone, both of the sensors receive substantially equal 
amounts of ambient light and the voltage in the reference junction remains 
unchanged. However, when one of the sensors (the trigger sensor) is 
occluded by a hand or other object in the detection zone, the difference 
between the light detected by the reference sensor and that detected by 
the trigger sensor changes the resistance of one sensor relative to the 
other. Thus, the voltage at the reference junction will change, and this 
change in voltage can be used to actuate the control circuit to start the 
dispensing operation. 
An important aspect of the invention is that the dispensed fluid does not 
contact the dispenser 20. Thus, the device rarely needs to be cleaned. 
Furthermore, for this reason, contamination of the dispenser 20 is 
unlikely, which in turn increases the effectiveness of disinfection of the 
user's hands H. Moreover, the present dispenser 20 dispenses fluids 
quickly, such that no waiting time is needed by the next user after the 
previous user finishes. Accordingly, the dispenser 20 may dependably 
service a large number of users in hospitals, clinics, public washrooms, 
commercial kitchens, or wherever else it is convenient to install it. 
From the foregoing detailed description, it will be evident that there are 
a number of changes, adaptations and modifications of the present 
invention which come within the province of those skilled in the art. 
However, it is intended that all such variations not departing from the 
spirit of the invention be considered as within the scope thereof as 
limited solely by the claims appended hereto.