Abstract:
A maintenance apparatus for a fluid ejection and vaporization device and a fluid ejection and vaporization device containing the maintenance apparatus. The maintenance apparatus includes a movable wiper blade, the wiper blade being attached to an arm on one end of the arm, wherein a distal end of the arm is attached to an air operated mechanism for moving the arm and for causing a sweeping movement of the wiper blade over an ejection head in the fluid ejection and vaporization device.

Description:
TECHNICAL FIELD 
       [0001]    The disclosure is directed to fluid ejection and vaporization devices and a maintenance apparatus and method for fluid ejection and vaporization devices. 
       BACKGROUND AND SUMMARY 
       [0002]    One of the applications of microfluidic ejection structures is to jet a solution on to another device where a secondary function may be performed. A common secondary function is to vaporize a solution using a heater such that the contents of the solution can be vaporized so as to deliver the solution as a gaseous substance. Applications of such technology include, but are not limited to, metering and vaporizing device for electronic cigarettes, vapor therapy, gaseous pharmaceutical delivery, vapor phase reactions for micro-labs, and the like. In all of these applications, a microfluidic ejection head is used to eject fluid onto a heated surface for vaporization of the fluid into a discharge conduit. For some applications, the fluids to be ejected have relatively low vaporization temperatures and thus can evaporate over time through ejection nozzles in the ejection head. For other applications, contamination of the ejection head between uses may be a problem. In some applications, the fluids may leave a residue on the ejection head that will, over time, inhibit the proper ejection of fluid from the ejection head or that may plug the ejection nozzles. Maintaining such devices so that precise fluid ejection is obtained is a problem due to the small size of such devices. Conventional maintenance devices for microfluidic ejection heads require a relatively large area for cleaning the ejection heads. 
         [0003]    Accordingly, what is needed is a maintenance apparatus that can be operated to clean the ejection head in order to maintain proper ejection of fluid. 
         [0004]    In view of the foregoing, an embodiment of the disclosure provides a maintenance apparatus for a fluid ejection and vaporization device. The maintenance apparatus includes a movable wiper blade, the wiper blade being attached to an arm on one end of the arm, wherein a distal end of the arm is attached to an air operated mechanism for moving the arm and for causing a sweeping movement of the wiper blade over an ejection head in the fluid ejection and vaporization device. 
         [0005]    In another embodiment there is provided a method for maintaining the cleanliness of an ejection head in a fluid ejection and vaporization device having a source of air flow through the fluid ejection and vaporization device. The method includes providing, within the fluid ejection and vaporization device, a movable wiper blade, the wiper blade being attached to an arm on one end of the arm, wherein a distal end of the arm is attached to an air operated mechanism for moving the arm and for causing a sweeping movement of the wiper blade over an ejection head in the fluid ejection and vaporization device. A flow of air is caused to flow through the fluid ejection and vaporization device in an amount sufficient to cause movement of the wiper blade in a sweeping motion from a first position to a second position across the ejection head. 
         [0006]    In some embodiments, the air operated mechanism is biased by a biasing device in order to return the wiper blade to the first position from the second position when the flow of air ceases. 
         [0007]    In other embodiments, the air operated mechanism is selected from an air bladder, a spring bellows, and an air operated flapper. 
         [0008]    In one embodiment, the air operated mechanism is an air operated flapper having a spring for biasing the air flapper to the first position. 
         [0009]    In some embodiments, air is caused to flow through the fluid ejection and vaporization device by inhaling vapors generated by the fluid ejection and vaporization device. 
         [0010]    In other embodiments, the wiper blade is disposed between an ejection head and a vaporizing heater in the fluid ejection and vaporization device. 
         [0011]    In another embodiment, the air operated mechanism is disposed on a mouthpiece side of the vaporizing heater between the vaporizing heater and mouthpiece of the fluid ejection and vaporization device. 
         [0012]    In some embodiments, the fluid ejection and vaporization device is an electronic cigarette. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    Other features and advantages of the inventive may be evident by reference to the following detailed description, drawings and claims wherein: 
           [0014]      FIG. 1  is a schematic view of an ejection head for a fluid ejection and vaporization device according to the disclosure. 
           [0015]      FIG. 2  is a side schematic illustration of a fluid ejection and vaporization device containing a cleaning apparatus according to a first embodiment of the disclosure, wherein a wiper blade of the cleaning apparatus is in a first position. 
           [0016]      FIG. 3  is a side schematic view of the fluid ejection device according to the first embodiment of the disclosure, wherein the wiper blade of the cleaning apparatus is in a second position. 
           [0017]      FIG. 4  is a side schematic view of the fluid ejection device according to the first embodiment of the disclosure, wherein the wiper blade of the cleaning apparatus has moved from the second position to the first position across an ejection head. 
           [0018]      FIG. 5  is a side schematic view of a wiper blade and air operated mechanism according to the first embodiment of the disclosure. 
           [0019]      FIG. 6  is a front schematic view of a wiper blade and air operated mechanism according to the first embodiment of the disclosure. 
           [0020]      FIG. 7  is a side schematic view of a fluid and vaporization ejection device containing a cleaning apparatus according to a second embodiment of the disclosure, wherein a wiper blade of the cleaning apparatus is in a first position. 
           [0021]      FIG. 8  is a side schematic view of the fluid ejection and vaporization device according to the second embodiment of the disclosure, wherein the wiper blade of the cleaning apparatus is in a second position. 
           [0022]      FIG. 9  is a side schematic view of the fluid ejection and vaporization device according to the second embodiment of the disclosure, wherein the wiper blade of the cleaning apparatus has moved from the second position to the first position across an ejection head. 
           [0023]      FIG. 10  is a front schematic view of a wiper blade and air operated mechanism according to the second embodiment of the disclosure. 
           [0024]      FIG. 11  is a side schematic view of a wiper blade and air operated mechanism according to the second embodiment of the disclosure. 
           [0025]      FIG. 12  is a side schematic view of a fluid ejection and vaporization device containing a cleaning apparatus according to a third embodiment of the disclosure, wherein a wiper blade of the cleaning apparatus is in a first position. 
           [0026]      FIG. 13  is a side schematic view of the fluid ejection and vaporization device according to the third embodiment of the disclosure, wherein the wiper blade of the cleaning apparatus is in a second position. 
           [0027]      FIG. 14  is a side schematic view of the fluid ejection and vaporization device according to the third embodiment of the disclosure, wherein the wiper blade of the cleaning apparatus has moved from the second position to the first position across an ejection head. 
           [0028]      FIG. 15  is a side schematic view of a wiper blade and air operated mechanism according to the third embodiment of the disclosure. 
           [0029]      FIG. 16  is a front schematic view of a wiper blade and air operated mechanism according to the third embodiment of the disclosure. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0030]    The disclosure is directed to fluid ejection and vaporizing devices as schematically in  FIGS. 2-4, 7-9 and 12-14  and maintenance apparatuses as shown schematically in  FIGS. 5-6, 10-11 and 15-16 . In all of the embodiment described herein, a fluid is ejected from an ejection head  10  ( FIG. 1 ) onto a vaporization heater  12  wherein the fluid is vaporized and flows through a mouthpiece out of the fluid ejection and vaporization device. The fluid ejected from the ejection head  10  is provided by a fluid reservoir  14  through ejection nozzles  16  in the ejection head  10 . The ejection head  10  may be a thermal microfluid ejection head or a bubble pump microfluid ejection head. Fluid ejection from the ejection head  10  is controlled so as to provide a predetermined amount of vapor to a user of the fluid ejection and vaporization device. In some embodiments, the fluid ejection and vaporization device is an electronic cigarette. In other embodiments, the fluid ejection and vaporization device may be a device for vapor therapy or for delivery of vaporized pharmaceutical compositions to a user. Regardless of the particular fluid ejection and vaporization device, the principal of operation of the maintenance apparatus is generally the same. 
         [0031]    For example, with reference to  FIGS. 2-6 , a fluid ejection and vaporization device  20  according to a first embodiment of the disclosure is illustrated. Such devices  20  may be used for a wide variety of applications wherein a liquid is ejected by the ejection head  10  onto the vaporizing heater  12  to provide a vapor stream as described above with reference to  FIG. 1 . Such devices  20  are typically hand held devices such as electronic cigarettes that have a mouth piece  22  for inhaling vapors generated by the device  20 . The mouthpiece  22  may include a vapor exit conduit  24  for flow of vapors out of the device  10 . As described above, it may be necessary to remove debris and contaminants from the ejection head  10  so that the nozzles  16  of the ejection head  10  do not become blocked or restricted whereby fluid ejection is inhibited or reduced. However, the small size of the fluid ejection and vaporization device  20  makes it difficult to use any kind of conventional ejection head cleaning mechanism. 
         [0032]    Accordingly, with reference so  FIGS. 2-6 , there is shown an air operated mechanism such as a bellows  26  or air bladder for moving a wiper blade  28  ( FIG. 6 ) across the ejection head  10  from a first position illustrated in  FIG. 2  to a second position illustrated in  FIG. 3  when suction is applied to the mouth piece  22 . In  FIGS. 2-4 , a first end  30  of the bellows  26  is fixed or stationary within the device  20 , and a second end  32  of the bellows  26  is compressed toward the first end  30  of the bellows  26  in the direction of arrow  34  when suction is applied to the mouthpiece  22 . A biasing device such as a spring  36  causes an arm  38  attached to the wiper blade  28  ( FIG. 6 ) to move away from the second end  32  of the bellows  26  thus sweeping the wiper blade  28  across the ejection head  10  from the first position shown in  FIG. 2  to the second position shown in  FIG. 3 . The arm  38  may be attached to the second end of the bellows  32  by a resilient connection such as rubber or thin plastic or a hinge  39 . When suction is removed from the mouthpiece  22 , the bellows  26  returns to an uncompressed state shown in  FIG. 4  thus again sweeping the wiper blade  28  across the ejection head from the second position ( FIG. 3 ) to the first position ( FIG. 4 ). The ends  30  and  32  of the bellows  26  may be biased away from each other by an internal or external spring. Air movement through the fluid ejection and vaporization device  20  that causes the bellows  26  to compress is illustrated by arrows  40  ( FIG. 3 ). 
         [0033]    When the bellows is in the uncompressed state shown in  FIGS. 2 and 4 , the arm  38  is at an angle  41  of less than 90 degrees with respect to the second end  32  of the bellows  26 , such as from about 20 to about 50 degrees, or from about 30 to about 45 degrees. When the bellows  26  is in the compressed state as shown in  FIG. 3 , the arm may be substantially perpendicular to the second end  32  of the bellows  26 , such as an angle of from about 45 degrees to less than about 90 degrees with respect to the second end  32  of the bellows  26 . 
         [0034]    With reference to  FIGS. 7-11 , a second embodiment of the disclosure is illustrated. In the second embodiment, an air operated mechanism such as an air flapper  50  is used in the fluid ejection and vaporization device  20  instead of the bellows  26  described above. The ejection head  10 , vaporization heater  12  and fluid reservoir  14  are described above and are disposed within the fluid ejection and vaporization device  20  as shown. 
         [0035]    In this second embodiment, the air flapper  50  has an arm  52  attached to a wiper blade  54  for moving the wiper blade  54  ( FIG. 10 ) across the ejection head  10  from a first position illustrated in  FIG. 7  to a second position illustrated in  FIG. 8  when suction is applied to the mouth piece  22 . The flapper  50  and arm  52  are attached by means of a hinge  56  to a support structure  58  within the fluid ejection and vaporization device. The hinge  56  enables pivotal movement of the flapper  50  and arm  52  relative to the support structure  58 . A biasing devices such as weak spring  60  is disposed between the flapper  50  and support structure  58  to bias the air flapper  50  to the first position shown in  FIGS. 7, 9 and 11 . The air flapper  50  is disposed in an air flow path indicated by arrows  40  at an angle with respect to the support structure  58  so that it can move the wiper blade across the ejection head  10  when there is air flow through the fluid ejection and vaporization device  20 . Accordingly, the air flapper  50  and arm  52  may be at an angle  61  ranging from about 25 to about 75 degrees relative to the support structure  58 , such as from about 30 to about 50 degrees. 
         [0036]    Moving from  FIGS. 7 to 9 , the operation of the air flapper  50  is illustrated schematically. In  FIG. 7 , there is no suction on the mouthpiece  22  and thus no air flow through the fluid ejection and vaporization device  20 . Therefore the wiper blade  54  is in the first position shown in  FIG. 7 . When suction is applied to the mouthpiece  22 , air, indicated by arrows  40  is caused to flow through the fluid ejection and vaporization device  20  causing the air flapper  50  to move toward the support structure  58  thereby compression the spring  60  and moving the wiper blade  54  across the ejection head  10  as shown in  FIG. 8 . When the suction on the mouthpiece  22  is terminated, the spring  60  causes the air flapper  50  to move away from the support structure  58  causing the wiper blade  54  to move across the ejection head  10  in the opposite direction back to the first position as shown in  FIG. 9 . As the wiper blade  54  sweeps across the ejection head in both directions from the first position ( FIGS. 7 and 9 ) to the second position ( FIG. 8 ), debris and excess fluid are removed from the surface of the ejection head  10 . The wiper blade  54  is made of a resilient material and will flex a sufficient amount to cause the wiper blade to remain in contact with the ejection head  10  regardless of the position of the wiper blade  54  in contact with the ejection head  10  in  FIGS. 7-9 . In the alternative, the arm  52  may flex as the wiper blade  54  moves across the ejection head  10  in the sequence of positions shown in  FIGS. 7-9 . 
         [0037]    A third embodiment of the disclosure is illustrated in  FIGS. 12-16 . In this embodiment, the air operated mechanism is again a bellows  70  or bladder, however, compression of the bellows  70  causes lateral movement of an arm  72  attached to a wiper blade  74  ( FIGS. 12-14 ) rather than angular movement of the arm  38  as shown in  FIG. 5  in the first embodiment of  FIGS. 1-6 . Unlike the first and second embodiment, the third embodiment does not require the use of the biasing devices  36  and  60  of the first two embodiments. As with the first embodiment, the bellows  70  may include an internal or external spring or biasing device in order to return the bellows  70  from a compressed position to an uncompressed position. 
         [0038]    In  FIG. 13 , a first end  76  of the bellows  70  is fixed or stationary within the device  20 , and a second end  78  of the bellows  70  is compressed toward the first end  76  of the bellows  70  in the direction of arrow  80  when suction is applied to the mouthpiece  22 . Accordingly, the bellows  70  is shown in a first uncompressed state in  FIG. 12  wherein the wiper blade  74  is adjacent a first end  82  of the ejection head  10 . When suction is applied to the mouthpiece  22 , air movement through the fluid ejection and vaporization device as indicated by arrows  86 , causes the bellows  70  to compress as shown in  FIG. 13  there by sweeping the wiper blade  74  across the ejection head  10  from the first end  82  to a second end  84  of the ejection head  10 . When suction is removed from the mouthpiece  22 , the bellows  70  returns to an uncompressed state shown in  FIG. 14  thus again sweeping the wiper blade  74  across the ejection head from the second end  84  ( FIG. 13 ) to the first end  82  ( FIG. 14 ). 
         [0039]    As with the first embodiment, the ends  76  and  78  of the bellows  70  may be biased away from each other by an internal or external spring. Air movement through the fluid ejection and vaporization device  20  that causes the bellows  70  to compress is illustrated by  FIG. 13 . 
         [0040]    It will be appreciated that the air operated mechanism of the third embodiment is simpler and has fewer moving parts than the air operated mechanism of the other two embodiments. 
         [0041]    In all of the embodiments described herein, the fluid ejection and vaporization device  20  may be made from a wide variety of materials including plastics, metals, glass, ceramic and the like provided the materials are compatible with the fluids to be ejected and vaporized by the device  20 . A particularly suitable material may be selected from polyvinyl chloride, high density polyethylene, polycarbonate, stainless steel, surgical steel, and the like. All parts, including the mouthpiece  22  that come in contact with fluids and vapors may be made of plastic. The wiper blade may be made of a resilient material such as an elastomeric material, natural rubber, fluoropolymer, and the like for wiping the ejection head  10 . As with the other components of the fluid ejection and vaporization device the wiper blade should be made of a material that is resistant to the fluids used in and vapors generated by the fluid ejection and vaporization device  20 . 
         [0042]    In the first and third embodiments, the bellows may be made from a resilient material such as cloth, fiberglass, plastic and the like. The air flapper of the second embodiment may be made of rigid material such as metal or plastic. 
         [0043]    While particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or can be presently unforeseen can arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they can be amended are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents.