Abstract:
An air control valve includes a body which includes a passage with an inlet and an outlet, and a chamber located between and communicated with the inlet and the outlet. The air control valve further includes a valve element rotatably disposed in the chamber, and a motor connected to the valve element for driving the valve element to rotate between a first position where the outlet communicates with the inlet and a second position where the valve element disconnects the outlet from the inlet.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This non-provisional patent application claims priority under 35 U.S.C. §119(a) from Patent Application No. 201110065057.6 filed in The People&#39;s Republic of China on Mar. 17, 2011. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to an electrically operated air control valve and in particular, to an air control valve for a medical respiratory device such as a nebulizer. 
       BACKGROUND OF THE INVENTION 
       [0003]    Medical nebulizers are widely used for treatment of cystic fibrosis, asthma and other respiratory diseases. A medical nebulizer usually comprises two passages one for delivering droplets of a medical liquid and the other for delivering an air stream which is generated by a recipient&#39;s inhalation through a mouthpiece. The two passages are joined together at a joint near the mouthpiece. Each passage is provided with a control valve for controlling the delivery of droplets of a medical liquid and air. 
         [0004]    The present invention is to provide a new air control valve for controlling the delivery of air/gas in a medical respiratory device such as a nebulizer. 
       SUMMARY OF THE INVENTION 
       [0005]    Accordingly, in one aspect thereof, the present invention provides an air control valve for a medical respiratory device, comprising: a body having a chamber with an inlet and an outlet; a valve element rotatably disposed within the chamber, the valve element defining a channel; and a motor comprising a shaft which is connected to the valve element for rotating the valve element between a first position where the channel of the valve element connects the outlet to the inlet of the body and a second position where the valve element disconnects the outlet from the inlet. 
         [0006]    Preferably, the shaft is loosely connected to the valve element to allow for slight differences between the axis of the shaft of the motor and the rotational axis of the valve element. 
         [0007]    Preferably, the valve element defines a non-circular mounting hole, and a coupling is fixed on the shaft of the motor and loosely fitted in the mounting hole, the coupling having a shape corresponding to that of the mounting hole. 
         [0008]    Preferably, wherein the mounting hole is a hexagonal hole and the coupling is a hexagonal nut fixed to the shaft by a threaded connection, the hexagonal nut being slightly smaller than the hexagonal hole. 
         [0009]    Preferably, the coupling comprises a connecting portion which engages the mounting hole and a base from which the connecting portion extends, and the valve element defines a recess for receiving the base of the coupling, the mounting hole extending from the recess in a direction away from the motor. 
         [0010]    Alternatively, the valve element defines a through hole extending along a rotational axis thereof, and the shaft of the motor extends through the through hole and one end of the shaft is supported by a bearing which is fixedly mounted at the closed end of the chamber of the body. 
         [0011]    Preferably, a limiting structure is formed between the body and the valve element for limiting rotation of the valve element between the first and second positions. 
         [0012]    Alternatively, the limiting structure comprises an arc shaped recess formed in the body and a protrusion formed on the valve element, the protrusion being movable in the recess when the valve element is rotated between the first and second positions. 
         [0013]    Alternatively, the limiting structure comprises an arc shaped block formed on an inner circumferential surface of the chamber and an arc shaped protrusion formed on an outer circumferential surface of the valve element, opposite circumferential ends of the block respectively contacting with opposite ends of the protrusion when the valve element is in the first and second positions. 
         [0014]    Alternatively, the chamber comprises an open end adjacent to the motor and a closed end away from the motor, a washer being sandwiched between the body and the motor for sealing the open end of the chamber. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    A preferred embodiment of the invention will now be described, by way of example only, with reference to figures of the accompanying drawings. In the figures, identical structures, elements or parts that appear in more than one figure are generally labeled with a same reference numeral in all the figures in which they appear. Dimensions of components and features shown in the figures are generally chosen for convenience and clarity of presentation and are not necessarily shown to scale. The figures are listed below. 
           [0016]      FIG. 1  is an assembled view of an air control valve in accordance with a first embodiment of the present invention; 
           [0017]      FIG. 2  is an exploded view of the valve of  FIG. 1 ; 
           [0018]      FIG. 3  illustrates a valve element of the air control valve of  FIG. 1 ; 
           [0019]      FIG. 4  illustrates a motor of the air control valve of  FIG. 1 ; 
           [0020]      FIG. 5  is a part sectional view of the air control valve of  FIG. 1 ; 
           [0021]      FIG. 6  is an exploded view of an air control valve in accordance with a second embodiment of the present invention; 
           [0022]      FIG. 7  illustrates a valve element of the air control valve of  FIG. 6 ; 
           [0023]      FIG. 8  illustrates the coupling of the air control valve of  FIG. 6 ; 
           [0024]      FIG. 9  is an exploded view of an air control valve in accordance with a third embodiment of the present invention; 
           [0025]      FIG. 10  is a part sectional view of the air control valve of  FIG. 9 ; 
           [0026]      FIGS. 11 &amp; 12  show a limiting structure of an air control valve in accordance with a fourth embodiment of the present invention; 
           [0027]      FIGS. 13 &amp; 14  show a limiting structure of an air control valve in accordance with a fifth embodiment of the present invention; and 
           [0028]      FIGS. 15 &amp; 16  show a limiting structure of an air control valve in accordance with a sixth embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0029]    The first preferred embodiment of the air control valve of the present invention will be described with reference to  FIGS. 1 to 5 . The air control valve according to the present invention may be used for medical nebulizers and other medical apparatus which need a control valve to control the delivery of air/gas. 
         [0030]    As shown in  FIGS. 1-5 , the air control valve comprises a body  10  which has a chamber  16 . The chamber  16  has an inlet  12 , an outlet  14 , a closed end and an open end opposite the closed end. 
         [0031]    The air control valve further comprises a valve element  30  pivotably disposed within the chamber  16 , a motor  50  connected to the valve element  30  to rotate the valve element  30  between a first position where the inlet  12  communicates with the outlet  14  and a second position where the outlet  14  is isolated from the inlet  12 . The valve element  30  has a channel  32  which connects the inlet  12  and the outlet  14  when the valve element  30  is located at the first position. 
         [0032]    A washer  80  is sandwiched between the body  10  and the motor  50  to seal the open end of the chamber  16 . The valve element  30  lightly contacts the washer  80  and is rotatable relative to the washer  80 . Optionally, seals may be provided between the inlet and/or outlet and the valve element to reduce leakage around the valve element. 
         [0033]    A limiting structure, for limiting rotation of the valve element  30  between the first position and the second position, is formed between the body  10  and the valve element  30 . Preferably, the limiting structure is configured such that the valve element  30  is rotatable through an angle which is greater than 90 degrees. In this embodiment, the motor  50  is a stepper motor and the valve element  30  is rotatable through  108  degrees between the first position and the second position. Specifically, the limiting structure comprises an arc shaped recess  18  formed in the body  10  in the edge of the open end of the chamber  16  and a protrusion  34  formed on the valve element  30 . The protrusion  34  moves along the recess  18  when the valve element  30  is rotated between the first and second positions with the protrusion bearing against ends of the recess when the valve element is in the first or second position. 
         [0034]    A coupling, in the form of a hexagonal nut  52 , is fixed to the end of the shaft  54  of the motor  50  by a threaded connection. One end of the valve element  30  facing the motor defines a hexagonal mounting hole  36  which has a shape corresponding to that of the nut  52 . The hexagonal nut  52  is slightly smaller than the hexagonal hole  36 . When assembled, the nut  52  is loosely fitted in the mounting hole  36  such that the valve element  30  is able to slightly move relative to the shaft  54  of the motor  50  and is rotated by the shaft  54  of the motor  50 . Thus, a slight deviation between the axis of the shaft  54  of the motor  50  and the axis of the valve element  30  can be compensated by the gap between the nut  52  and the mounting hole  36  of the valve element  30 , to thereby avoid the valve element  30  being jammed in the chamber  16  due to a slight misalignment of the motor. 
         [0035]    The motor  50  has a pair of mounting lugs each having a through hole  56 . The body  10  defines a pair of attachment holes  19  at opposite sides of the open end of the chamber  16 . The motor  50  is attached to the body  10  by a pair of fasteners  58  which pass through the through holes  56  of the motor  50  and engage with the attachment holes  19  of the body  10 . In this embodiment, the fasteners  58  are screws. 
         [0036]    As shown in  FIG. 5 , in use, the valve element  30  is rotated by the motor  50  to the first position where the channel  32  of the valve element  30  connects the inlet  12  to the outlet  14 . Thus air can flow through the chamber  16  from the inlet  12  to the outlet  14  via the channel  32 . To close the valve, the motor rotates the valve element to the second position where the channel  32  is not aligned with the inlet or outlet, thus disconnecting the outlet from the inlet. 
         [0037]      FIGS. 6-9  show an air control valve in accordance with a second embodiment of the present invention. This air control valve is similar to the air control valve of the first embodiment except that the nut is replaced by a coupling  60 . 
         [0038]    The coupling  60  comprises a base  62 , a connecting portion  64  protruding from the base  62 . A fixing hole  66  is defined at the center of coupling  60  such that the shaft  54  of the motor  50  may be fixed in the fixing hole  66  to thereby fix the coupling  60  to the shaft  54 . The valve element  30  defines a recess  38  at one end thereof adjacent to the motor  50 . The shape of the recess  38  corresponds to that of the base  62  of the coupling  60 . The valve element  30  further defines a mounting hole  36  which has a shape corresponding to that of the connecting portion  64  of the coupling  60 . The hole  36  starts from the recess  38  and extends axially in a direction away from the motor  50 . When assembled, the base  62  of the coupling  60  is received in the recess  38  of the valve element  30  and the connecting portion  64  is received in the mounting hole  36 , such that the valve element  30  is rotatable with the coupling  60  which is driven by the shaft  54  of the motor  50 . The shape of the connecting portion  64  of the coupling  60  is non-circular, such as triangle, square, rectangular, hexagonal and so on. The shape of mounting hole  36  corresponds to that of the connecting portion  64  but the size of the connecting portion  64  is slightly smaller than that of the mounting hole  36  such that a small gap is formed between the connecting portion  64  and the mounting hole  36 . 
         [0039]      FIGS. 9-10  show an air control valve in accordance with a third embodiment of the present invention. This air control valve is similar to the air control valve of the first embodiment except that the valve element is fixed directly to the shaft. The valve element  30  has a through hole  31  extending along the rotational axis thereof. The shaft  54  of the motor  50  extends through the through hole  31  and the distal end of the shaft  54  is supported by a bearing  39  fixedly mounted in the closed end of the chamber  16 . The valve element  30  is a press fit on the shaft  54  and therefore rotatable with the shaft  54 . 
         [0040]      FIGS. 11-12  show a limiting structure of an air control valve in accordance with a fourth embodiment of the present invention. The limiting structure comprises an arc shaped recess  18  formed in the closed end of the chamber  16 . The valve element  30  is provided with a protrusion  34  which is slidably received in the arc shaped recess  18  to limit the angle of rotation of the valve element. 
         [0041]      FIGS. 13-14  show a limiting structure of an air control valve in accordance with a fifth embodiment of the present invention. The limiting structure comprises an arc shaped recess  18  defined in the closed end of the chamber  16 . The valve element  30  has an arc shaped protrusion  34  that is slidably received in the arc shaped recess  18 . A plurality of discrete ribs  182  are formed along a side the arc shaped recess  18  for slidably contacting with the protrusion  34  to thereby decrease friction between the body  10  and the valve element  30 . 
         [0042]      FIGS. 15-16  show a limiting structure of an air control valve in accordance with a sixth embodiment of the present invention. The limiting structure comprises an arc shaped block  24  formed on the inner circumferential surface of the chamber  16 . The valve element  30  is provided with an arc shaped protrusion  34  on the outer circumferential surface thereof. The inner diameter of the arc shaped block  24  is smaller than the outer diameter of the arc shaped protrusion  34 . When the valve element  30  is in the first position one circumferential end of the protrusion  34  contacts with one circumferential end of the block  24 , and when the valve element  30  is in the second position the other circumferential end of the protrusion  34  contacts with the other circumferential end of the block  24 . 
         [0043]    In the description and claims of the present application, each of the verbs “comprise”, “include”, “contain” and “have”, and variations thereof, are used in an inclusive sense, to specify the presence of the stated item but not to exclude the presence of additional items. 
         [0044]    Although the invention is described with reference to one or more preferred embodiments, it should be appreciated by those skilled in the art that various modifications are possible. Therefore, the scope of the invention is to be determined by reference to the claims that follow.