Abstract:
An electrically-powered fluid sprayer employs a piezoelectric fluid pump that includes an inlet port, an outlet port, a pump chamber, and a piezoelectric element that is deformed and displaced by electrical signals supplied thereto to vary the volume of the pump chamber. Such displacement pumps fluid into the inlet port and into the pump chamber and discharges fluid from the pump chamber out the outlet port. The inlet port is in fluid-communication with a fluid reservoir. Spin mechanics may be disposed downstream from the outlet port of the fluid pump and upstream from the discharge nozzle. The piezoelectric fluid sprayer may be extended to include a dual chamber piezoelectric pump that pumps different fluids (e.g., a liquid and air). The output of the dual chamber pump is mixed in a manifold and supplied downstream to the discharge nozzle. Spin mechanics may be employed in the fluid stream upstream from the discharge nozzle after the mixing.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates broadly to electrically-powered fluid pumps. More particularly, this invention relates to an electrically-powered fluid pump contained in a spray head which is retrofittable onto existing pump spray containers. 
   2. State of the Art 
   Many household and industrial products are sold in containers that include a sprayer. These products include cleansers, insecticides, polishes, waxes, etc. There are several kinds of sprayers used with these products. Perhaps the most common is the push button or trigger operated pump which is seen most frequently on liquid cleansers. It has the advantage of being environmentally friendly but the disadvantage of delivering fluid in a series of pulses rather than in a continuous spray. 
   Another well known sprayer is the aerosol can which is sealed and charged with a gas propellant. This sprayer has the advantage that it dispenses fluid in a continuous spray, but has several disadvantages. One disadvantage is that the can cannot be refilled. Another disadvantage is that, depending on the gas used to charge the container, it can be environmentally unfriendly. Moreover, environmentally friendly propellants do not charge as well as the unfriendly gases. 
   Still another popular sprayer is the air pump sprayer seen most frequently with insecticides and liquid garden products. The pump sprayer includes a hand operated air pump which is used to charge the container with compressed air. After it is charged, it operates much like an aerosol can. The pump sprayer is environmentally friendly but requires a lot of effort to keep it charged because air is not as efficient a propellant as environmentally unfriendly gases such as FREON or hydrocarbon gasses. 
   In recent years there has been some experimentation with electrically powered pump sprayers. Most of these devices include a spray mechanism which is similar to the ubiquitous push button (or trigger) pump sprayer but which is coupled to a battery powered electric motor by a linkage which converts the rotary action of the motor to an oscillatory motion to drive the pump piston. Many of these battery operated pump sprayers are designed to work only with a specially constructed bottle, i.e. they are not retrofittable to existing pump spray bottles. They also are heavy, expensive, and have poor power consumption (and reduced battery life) due to the weight and cost of the electric motor. Many of these battery powered pumps also have large priming volumes, thus causing a delay between the time the pump is activated and the time liquid begins to be dispensed. Significantly, these pumps do not really provide a constant spray. They provide a continuous pulsed spray like that obtained by repeatedly squeezing the trigger of pushing the button on a hand operated spray pump. 
   SUMMARY OF THE INVENTION 
   It is therefore an object of the invention to provide an electrically-powered pump spray head that can be readily adapted to interface to existing pump spray bottles. 
   It is another object of the invention to provide an electrically-powered pump sprayer that has improved power consumption, lower costs, and reduced weight. 
   It is a further object of the invention to provide an electrically-powered sprayer that has a small-sized priming volume which is preferably self-priming during operation of the pump. 
   It is also an object of the invention to provide an electrically-powered sprayer that provides a substantially constant spray from a discharge nozzle. 
   In accord with these objects, which will be discussed in detail below, an electrically-powered fluid sprayer employs a piezoelectric fluid pump that includes an inlet port, an outlet port, a pump chamber, and a piezoelectric element that is deformed and displaced by electrical signals supplied thereto to vary the volume of the pump chamber. Such displacement pumps fluid into the inlet port and into the pump chamber and discharges fluid from the pump chamber out the outlet port. The inlet port is in fluid communication with a fluid reservoir. Spin mechanics are disposed downstream from the outlet port of the fluid pump and upstream from the discharge nozzle. 
   It will be appreciated that the electrically-powered sprayer of the present invention can be readily adapted to interface to existing pump spray bottles. It also has improved power consumption, lower costs, and reduced weight. It also can be readily adapted to have a small priming volume which is preferably self-priming during operation of the pump. It can also be readily adapted to provide a substantially constant spray from the discharge nozzle. 
   According to one embodiment of the invention, the piezoelectric element of the pump comprises a piezoelectric diaphragm. 
   According to another embodiment of the invention, the piezoelectric element is driven by battery powered circuitry. 
   According to another embodiment of the invention, the elements of the electrically-powered fluid sprayer are supported in a hand-holdable housing with a trigger, and the pizeoelectric element is activated by the user pressing the trigger. 
   In another aspect of the present invention, an electrically-powered fluid sprayer employs a dual chamber piezoelectric fluid pump that includes a first inlet port, a first outlet port, a first pump chamber, a second inlet port, a second outlet port, a second pump chamber, and at least one piezoelectric element that is deformed and displaced by electrical signals supplied thereto to vary the volume of the first and second pump chambers. Such displacement pumps a first fluid into the first inlet port and into the first pump chamber and discharges fluid from the first pump chamber out the first outlet port. Such displacement also pumps a second fluid into the second inlet port and to the second pump chamber and discharge fluid from the second pump chamber out the second outlet port. The inlet ports are in fluid communication with separate fluid reservoirs (or possibly one in fluid communication with a fluid reservoir and the other in fluid communication with ambient air). A mixing manifold is disposed downstream from the first and second outlet ports of the fluid pump and upstream from the discharge nozzle. The mixing manifold is adapted to mix the first and second fluids discharged from the first and second outlet ports of the pump. Spin mechanics may be disposed upstream from the discharge nozzle. 
   According to one embodiment of the invention, the first and second pump chambers are disposed on opposite sides of a single piezoelectric element. 
   According to another embodiment of the invention, the first and second pump chambers each include a separate and distinct piezoelectric element. 
   Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  is an exploded view of the spray head of the invention. 
       FIG. 1B  is a cross-sectional view of the spray head of the invention. 
       FIG. 2  is a cross-sectional view of a first embodiment of a piezoelectric fluid and air pump of the invention. 
       FIG. 3  is a cross-sectional view of a second embodiment of a piezoelectric fluid and air pump of the invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Turning now to  FIGS. 1A and 1B , a battery operated spray head  10  according to the invention includes an ergonomic housing  12  with three parts—left side part  12 A, right side part  12 B, and top cover  12 C. The left and right side parts  12 A,  12 B support a two part threaded bottle coupling  14  having a retainer  14 A and a closure  14 B. The housing  12  displays a discharge nozzle  16  and a trigger  18 . The left and right side parts  12 A,  12 B of the housing  12  extend about the coupling  14  in a shape adapted to be comfortably gripped by the hand of the user when the user squeezes the trigger  18 . An electrical power source  22  (batteries  22 A and contacts  22 B), a dual chamber piezoelectric liquid and air pump  24 , a mixing manifold  26  and optional swirl mechanics  28  are mounted inside the housing  12  when assembled. The trigger  18  is arranged so that when it is squeezed, it operates a vent valve  30  and an electrical switch  32 . The valve  30 , which preferably is realized by a cylindrical body  30 A that houses a spring  30 B and two part piston valve member  30 C as shown, selectively opens an air path from the atmosphere to the interior of the bottle via a vent opening (not shown) into the valve  30  and a vent passage  34  which extends from the valve body  30 A to the coupling  14 . The electrical switch  32  selectively couples the electrical power source  22  to the piezoelectric liquid and air pump  24  to drive the pump  24  as described below. The operation of the vent valve  30  and the switch  32  can be linked to the trigger  18  for simultaneous actuation or series actuation when energizing the pump  24 . The top cover  12 C preferably can be removed by the user to gain access to the batteries  22 A in order to replace the batteries  22 A as needed. 
   The retainer  14 A includes a vent port (not shown) that terminates a vent passageway  36  through the retainer  14 A into the interior of a bottle (not shown) during use. The vent passage  34  of the vent valve  30  mates to the vent port of the retainer  14 A to provide fluid communication between the vent valve  30  and the interior of the bottle during use. The retainer  14 A also includes a liquid supply port (not shown) that terminates a liquid supply passageway  38  through the retainer. A dip tube (not shown) extends from the liquid supply passageway  38  into the interior of the bottle as is well known. The liquid inlet port  47  of the pump  24  mates to the liquid supply port of the retainer  14 A to provide fluid communication between liquid inlet port  47  and the interior of the bottle to supply liquid thereto during use. The bottle may hold any one of a number of household and industrial liquid products (such as cleansers, insecticides and other liquid garden products, polishes, waxes), personal care products, or other liquid products. 
   The dual chamber piezoelectric liquid and air pump  24  includes the liquid inlet port  47 , a liquid outlet port  49 , an air inlet port  51  (which may be realized by a passageway through the underside of the pump, which is not shown in  FIG. 1A , but is seen in  FIG. 2 ) and an air outlet port  53 . The liquid outlet port  49  is in fluid communication with one leg  26 A of the mixing manifold  26 , while the air outlet port  53  is in fluid communication with the other leg  26 B of the mixing manifold  26 . The air inlet port  51  of the pump  24  provides an air path to atmosphere. 
   As described below in detail, the pump  24  includes a liquid pump chamber in fluid communication with the liquid inlet port  47  and the liquid outlet port  49 , as well as an air pump chamber in fluid communication with the air inlet port  51  and the air outlet port  53 . One or more piezoelectric diaphragms are deformed and displaced in response to electric signals applied thereto to change the volume of the liquid pump chamber and the air pump chamber, respectively. The electric signals that drive the piezoelectric diaphragm(s) are generated by drive circuitry, which is preferably integrated as part of the pump  24 , that is coupled in either a wired or wireless manner to the electrical power source  22  via the switch  32 . Such displacement causes liquid to be drawn into the liquid inlet port  47  and into the liquid pump chamber and then discharged out the liquid outlet port  49 . It also causes air to be drawn into the air inlet port  51  and into the air pump chamber and then discharged out the air outlet port  53 . 
   As previously described, the liquid outlet port  49  and the air outlet port  53  are in fluid communication with respective legs  26 A,  26 B of the mixing manifold  26 , which includes a mixing chamber  27  that is configured to channel the flow of liquid and air discharged from the liquid outlet port  49  and air outlet port  53  to create a fluid or gaseous mixture. For example, the liquid and air can be mixed such that the air is entrained into the fluid for purposes of reducing fluid particle size and/or creating a fluid foam. 
   The mixing manifold  26  also supports optional spin mechanic  28  and the discharge nozzle  16 , which are operably disposed downstream from the mixing chamber  27 . The spin mechanics  28  impart a swirl to fluid passing therethrough for discharge from the nozzle  16 . The discharge nozzle  16  is preferably adapted to allow the user to select different spray patterns and to permit the flow channels to be turned on and off by rotating the nozzle  16  as is well known in the liquid sprayer arts. 
   As shown in the exemplary embodiment of  FIG. 2 , the dual chamber piezoelectric liquid and air pump  24  includes a pump body  71  that houses a piezoelectric diaphragm  73  supported by a first sealing member  75  (e.g., O-ring) and a second sealing member  77  (e.g., sealing washer). The pump body  71 , the piezoelectric diaphragm  73 , and the supporting elements may be square, rectangular, or annular in nature and preferably have a maximum dimension on the order of 25–100 mm. The piezoelectric diaphragm  73  has a liquid-contacting surface  79  disposed opposite an air-contacting surface  81  as shown. The lower part  71 A of the body and the liquid-contacting surface  79  define a liquid pump chamber  83 , while the upper part  71 B of the body and the air-contacting surface  81  define an air pump chamber  85 . A liquid inlet check valve  87  is operably disposed between the liquid inlet port  47  and the liquid pump chamber  83 . A liquid outlet check valve  89  is operably disposed between the liquid pump chamber  83  and the liquid outlet port  49 . Similarly, an air inlet check valve  91  is operably disposed between the air inlet port  91  and the air pump chamber  85 . An air outlet check valve  93  is operably disposed between the air pump chamber  85  and the air outlet port  93 . 
   Drive circuitry  95  is operably coupled to the electrical power source  22  via the electrical switch  32 . The drive circuitry  95  applies a time varying electric signal to the piezoelectric diaphragm such that it is deformed and displaced in an oscillating manner to thereby vary the size of the liquid pump chamber  83  and the air pump chamber  85 , respectively. During the liquid intake stroke (displacement of the diaphragm  77  away from liquid inlet port  47  and the liquid outlet port  49 ), the diaphragm  77  draws liquid into the liquid inlet port  47  and into the liquid pump chamber  83 . During the liquid discharge stroke (displacement of the diaphragm  77  toward the liquid inlet port  47  and the liquid outlet port  49 ), the diaphragm  77  discharges the liquid from the fluid pump chamber  83  out the liquid outlet port  49 . During the air intake stroke (which corresponds to the liquid discharge stroke), the diaphragm  77  draws air into the air inlet port  51  and into the air pump chamber  85 . During the air discharge stroke (which corresponds to the liquid intake stroke), the diaphragm  77  discharges the air from the air pump chamber  85  out the air outlet port  53 . 
   The piezoelectric diaphragm  77  is preferably formed with a natural shape that is flat or dome-shaped and from a polycrystalline ferroelectric material as set forth in International Patent Application WO 2004/084274, herein incorporated by reference in its entirety. In this illustrative embodiment, the piezoelectric diaphragm  77  can be driven with a sinusoidal or square wave alternating current as set forth therein. The pump frequency (which corresponds to the frequency of oscillation of the AC drive signal applied to the diaphragm) can be varied based upon the particular application, but is preferably significantly less than 20 kHz and most preferably between 35 Hz and about 85 Hz. Such frequencies generate a substantially continuous spray which is discharged through the discharge nozzle. 
   In an alternate embodiment as shown in  FIG. 3 , the dual chamber piezoelectric liquid and air pump  24  includes a pump body  101  that houses first and second piezoelectric diaphragms  103 ,  105 . The first piezoelectric diaphragm  103  is supported by sealing member  107  (e.g., O-ring) and a sealing member  109  (e.g., sealing washer). The second piezoelectric diaphragm  105  is supported by sealing member  111  (e.g., O-ring) and a sealing member  113  (e.g., sealing washer). The first piezoelectric diaphragm  103  has a liquid-contacting surface  115  disposed opposite a rear-venting surface  117  as shown. The second piezoelectric diaphragm  105  has an air-contacting surface  119  disposed opposite a rear-venting surface  121  as shown. The lower part  101 A of the body and the liquid-contacting surface  115  of the first piezoelectric diaphragm  103  define a liquid pump chamber  123 , while the upper part  101 B of the body and the air-contacting surface  119  of the second piezoelectric diaphragm  105  define an air pump chamber  125 . The rear-venting surfaces  117  and  121  and an interior body wall  101 C define vent chambers  135 A,  135 B that are vented to atmosphere by passageways  137 A and  137 B as shown. A liquid inlet check valve  87  is operably disposed between the liquid inlet port  47  and the liquid pump chamber  83 . A fluid outlet check valve  89  is operably disposed between the liquid pump chamber  123  and the liquid outlet port  49 . Similarly, an air inlet check valve  91  is operably disposed between the air inlet port  91  and the air pump chamber  125 . An air outlet check valve  93  is operably disposed between the air pump chamber  125  and the air outlet port  93 . 
   Drive circuitry  123  is operably coupled to the electrical power source  22  via the electrical switch  32 . The drive circuitry  123  applies a time varying electric signal to the piezoelectric diaphragms  103 ,  105  such that they are deformed and displaced in an oscillating manner to thereby vary the size of the liquid pump chamber  123  and the air pump chamber  125 , respectively. During the liquid intake stroke (displacement of the first piezoelectric diaphragm  103  away from the liquid inlet port  47  and the liquid outlet port  49 ), the first piezoelectric diaphragm  103  draws liquid into the liquid inlet port  47  and into the liquid pump chamber  123 . During the liquid discharge stroke (displacement of the first piezoelectric diaphragm  103  toward the liquid inlet port  47  and the liquid outlet port  49 ), the first piezoelectric diaphragm  103  discharges the liquid from the liquid pump chamber  123  out the liquid outlet port  49 . During the air intake stroke (which preferably is synchronous to the liquid discharge stroke), the second piezoelectric diaphragm  105  draws air into the air inlet port  51  and into the air pump chamber  125 . During the air discharge stroke (which preferably is synchronous to the liquid intake stroke), the second piezoelectric diaphragm  105  discharges the air from the air pump chamber  125  out the air outlet port  53 . 
   The piezoelectric diaphragms  103 ,  105  are preferably formed with a natural shape that is flat or dome-shaped and from a polycrystalline ferroelectric material as set forth in International Patent Application WO 2004/084274. In this illustrative embodiment, the piezoelectric diaphragms  103 ,  105  can be driven with a sinusoidal or square wave alternating current as set forth therein. The pump frequency (which corresponds to the frequency of oscillation of the AC drive signal applied to the diaphragms) can be varied based upon the particular application, but is preferably significantly less than 20 kHz and most preferably between 35 Hz and about 85 Hz. 
   The liquid inlet and outlet check valves  87 ,  89  as well as the air inlet and outlet check valves  91 ,  93  are preferably flexible disk shaped members that selectively block fluid communication through a passageway as are well known in the liquid sprayer arts. In the preferred embodiment, such check valves may be realized by an elliptical disk that is the same size and shape as the end of a tubular passageway formed at a 45° angle to the axis of the tubular passageway. The inlet and outlet check valves have absolute minimum bulk. Moreover, the mass of such check valves are minimized so that they react rapidly to the action of the piezoelectric diaphragm(s). Such valves preferably allow the respective pump chambers  83 ,  85  to be self-priming since employment of the two valves for each respective chamber may create a sufficient vacuum to draw fluid into the respective chamber. Other small-size check valves, such as flapper valves or spring-biased ball valves may be used as well. In alternate embodiments, the outlet check valves of the system may be omitted. 
   There have been described and illustrated herein several embodiments of a fluid sprayer employing a dual chamber piezoelectric pump chamber. While particular embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. Thus, while discrete piezoelectric pumping chambers have been disclosed for pumping a liquid and air for downstream mixing in the mixing manifold, the discrete chambers can be used for pumping any combination of fluids (including gases) for downstream mixing and dispensing. Furthermore, while manually-actuatable venting mechanisms have been disclosed, it will be appreciated that other venting mechanisms can be used as well. For example, a ‘static’ valve may be provided in communication with the drawn upon liquid reservoir for the purpose of venting the liquid reservoir. The ‘static’ vent is activated by negative pressure generated in the liquid reservoir as the result of pumping liquid from the reservoir. In addition, while particular types, shapes and configurations of piezoelectric actuators have been disclosed, it will be understood the other types, shapes and configurations can be used. Furthermore, additional electrically-powered components may be integrated into the system. For example, a battery-powered piezoelectric atomizing element can be placed in the fluid path downstream from the pump. The atomizing element is driven such that it vibrates, typically at ultrasonic frequencies, in a manner that atomizes the fluid directed thereto. Moreover, while particular configurations have been disclosed in reference to a bottle-mounted hand-held liquid sprayer device, it will be appreciated that other configurations could be used as well. For example, the dual chamber pump system described herein can be used in a wide variety of bottle-mounted hand-held liquid sprayer heads (with or without neck-downed handles), remote sprayer configurations and stationary devices (such as fragrance atomizers which may be mounted on the floor, tabletop, or wall). In yet other embodiments, a piezoelectric actuated single pump chamber design can be used to pump fluid, such as a liquid, as part of a fluid sprayer head. Still in yet other embodiments, alternate electrical power sources, such as mains-based transformers and the like, may be used to drive the piezoelectric elements of the fluid spray system described herein. It will therefore be appreciated by those skilled in the art that yet other modifications could be made to the provided invention without deviating from its spirit and scope as claimed.