Abstract:
A canister assembly for use with a medical suction or aspiration device having a ball float assembly defined in the lid. The lid accepts a replaceable filter cartridge containing a filter element. The ball float engages the replaceable filter cartridge when the canister is near full.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates in general to canisters. More specifically, the invention is directed to canisters for use with a medical suction or aspirator device for the collection of fluids during medical procedures. 
       BACKGROUND OF THE INVENTION 
       [0002]    Medical suction and aspiration devices are used to remove bodily fluids during medical procedures or emergency situations. These suction and aspiration devices often include canisters to receive the bodily fluids. Current devices used for aspiration during surgical procedures include a wandlike collection device connected via a hose to a collection canister. A vacuum pump is also connected to the canister, thereby creating a vacuum in the canister and in the collection device. As aspirated fluids are removed from the body, they are collected in the collection canister. 
         [0003]    As it is desirable to minimize contact between the suctioned fluid within the canister and the device operator, and to avoid having fluids sucked into the vacuum pump, it is desirable to provide a means for the isolating the fluids from the orifice to which the vacuum source is connected. 
       BRIEF SUMMARY OF THE INVENTION 
       [0004]    This invention relates to a canister having a filtered, shut off device to retain suctioned fluids within the canister. The device consists of a ball float valve which is capable of making contact with a replaceable filter cartridge. An absorbent valve which constricts the flow of air and fluids when wet, is disposed within the filter cartridge to prevent fluid flow through the vacuum source. In operation, when the canister becomes full, the ball float will rise, blocking the bottom inlet to the filter cartridge. Any fluids that may leak past the ball float will contact the absorbent valve, which will ensure that no fluids are able to enter the vacuum source. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  shows the device in transparent perspective exploded view. 
           [0006]      FIG. 2  shows the filter cartridge and filter element in perspective transparent view. 
           [0007]      FIG. 3  shows the filter cartridge in cross-sectional view showing the ball float in position to stop the flow of fluid into filter cartridge  10 . 
           [0008]      FIG. 4  shows a transparent perspective view of the bottom of the lid of the device. 
           [0009]      FIG. 5  shows the lid of the device in transparent cross-sectional view. 
           [0010]      FIG. 6  shows the lid of the device having the filter cartridge inserted therein, in transparent, cross sectional view. 
       
    
    
     DESCRIPTION OF THE INVENTION 
       [0011]      FIG. 1  shows an exploded view of the device of the present invention. When in use, canister  50  is used to collect aspirated bodily fluids. In practice, after use, canister  50  is often emptied and cleaned for re-use, as is lid  40 . Canister  50  may be composed of styrene acrylonitrile or another hard plastic. Lid  40  uses replaceable filter cartridge  10 , which may be replaced between uses of the device. The novelty of the invention is in the design of lid  40 , and filter cartridge  10  to allow the replacement of filter cartridge  10  for re-use. Note that lid  40  and filter cartridge  10  wherein the novel aspects of the invention reside, may be used with canister bodies  50  of many different types. Lid  40  contains the housing for the ball float valve as well as the inlet port to which the suction wand is typically connected. Ball float  30  rests inside lid  40 , as will be explained later. Replaceable filter cartridge  10  retains filter element  20  therein and also includes the orifice for connection to the vacuum source. 
         [0012]      FIG. 2  shows the filter cartridge in transparent perspective view. Preferably, filter cartridge  10  is composed of a low density polyethylene As can be seen, filter element  20  consists of a hollow cylinder  220  closed at one end  210  and being open at the other end. Opening  200  opens to a cylindrical void inside filter element  20 . Filter element  20  slides into the body of filter cartridge  10 , engaging nipple  130  in opening  200  and is held in place by a plurality of ridges  140  defined along the inner surface of cylindrical portion of filter cartridge  10 . Nipple  130  is in fluid communication with orifice  110  for connection to vacuum source. In operation, a vacuum is created by extracting air through orifice  110  and thereby through the void  200  in filter element  20 . Air is able to flow in through the walls  220  of filter element  20  as long as filter element  20  has not become wet, thereby creating a negative pressure condition within canister  50 . 
         [0013]    Lip  120  define on filter cartridge  10  engages in opening  430  defined in lid  40  and is held in place thereon by frictional engagement.  FIG. 6  shows a cross-sectional view or lid  40  having filter cartridge  10  inserted therein. Opening  150  defined in the bottom of filter cartridge  10  is shaped and sized to engage the outer surface of ball float  30  when ball float  30  has floated up and is in contact with the bottom of filter cartridge  10 . Preferably, the lower portion of the outer wall of filter cartridge  10  is slightly flexible. 
         [0014]      FIG. 3  shows a cross-sectional view of filter cartridge  10  having filter element  20  inserted therein and also shows ball float  30  in contact with the bottom opening  150  of filter cartridge  10 . Ball float  30  would be in this position in the event that canister  50  becomes filled with fluid, thereby causing ball float  30  to float up from its resting position to contact the bottom opening  150  of filter cartridge  10 . 
         [0015]      FIG. 4  shows a perspective transparent view of the bottom of lid  40  of the device. Lid  40  defines receptacle  420  which holds ball float  30  and which received filter cartridge  20 . Ball float  30  held with in receptacle  420  by retaining tabs  410  which can be flexed outwardly such as to allow the removal of ball float  30  from receptacle  420  for cleaning purposes. However, under normal circumstances, ball float  30  is unable to move past retaining tabs  410 . Preferably, lid  40  is composed of a high density polyethylene and ball float  30  is composed of polypropylene, and may be hollow. 
         [0016]    The distance between the bottom of retaining tabs  410  and the bottom wall  425  of receptacle  420  is sized to be greater than the diameter of ball float  30 . 
         [0017]    In normal operation, ball float  30  will rest against bottom wall  425  of receptacle  420  and, in situations where canister  50  has become filled with fluid, ball float  30  will float up until further movement is prevented by bottom opening  150  of filter cartridge  10 . Filter cartridge extends downward into receptacle  420 , such that bottom opening  150  of filter cartridge  10  is even with retaining tabs  410 , as shown in  FIG. 6 . Thus, when ball float  30  has floated up and is in contact with retaining tabs  410 , opening  150  of filter cartridge  10  will also be blocked by ball float  30 . The width of receptacle  420  is slightly larger than the diameter of ball  30 , allowing vertical movement of ball float  30  within receptacle  420 . 
         [0018]    Also shown in  FIG. 4  are other design elements of lid  40  including structural ridges  460 , inner lip  470  which engages the upper lip of canister  50 , in this case utilizing a snap fit, although other means of engagement may also be used. Also shown is inlet port  450  which connects on the upper surface of lid  40  (not shown) with the collection device, typically an aspirator. Cap  440  may be used to close inlet port  450  from the outside when no collection device is connected thereto. Lid  40  defines opening  430  on the top thereof for reception of the filter cartridge  10  having filter element  20  inserted therein. 
         [0019]      FIG. 5  is a cross-sectional transparent view of lid  40  showing in more detail receptacle  420  in which ball float  30  is disposed and the size and spacing of retaining tabs  410 , which keep ball float  30  in place during normal operation of the device. Filter cartridge  10  is inserted into opening  430  defined in the top of lid  40 . The ridge of bottom opening  150  of filter cartridge  10  extends to the bottom level of retaining tabs  410 , such that when ball float  30  has floated upward, a portion of ball float  30  will extend above retaining tabs  410  to close the bottom of filter cartridge  10 , as shown in  FIG. 3 . 
         [0020]    As in many instances, canister  50  and lid  40  are reused by medical personnel. It is intended that filter cartridge  10  along with filter element  20  inserted therein be replaceable and sold separately from the rest of the device such that lid  40  and canister  50  may be reused many times. It is also intended that ball float  30  be easily removed from receptacle  420  by forcing it past retaining tabs  410 , which are flexible enough to allow the passage of ball float  30  upwards through opening  430  when pressure is applied from the bottom of ball float  30 . 
         [0021]    Filter element  20  includes an open end  200 , which engages nipple  130  on the interior of filter cartridge  10 , an outer wall  220 , and a closed end  210 . The outer wall  220  and the closed end  210  have an interior surface, an exterior surface, and cooperate to define an interior space, cylindrically-shaped space. The material of the absorbent valve  34  may be of a porous structure having interstitial voids, such as between sintered beads or intertwined filaments, thus creating a capillary effect therein. 
         [0022]    Filter element  20  is preferably made from a material exhibiting a hydrophilic or hygroscopic property. This fluid absorptive property of filter element  20  is aided, at least in part, by the capillary action of the interstitial voids of the material. The structure can be made from sintering plastic beads or powders. Such a structure may be formed by a polyethylene plastic having an added cellulose gum filler. Additionally, any suitable plastic or polymer capable of having a porous structure may be a suitable material substitute to support a cellulose gum filler. The cellulose gum filler is used as the reactant medium to reduce the interstitial voids, thus slowing and ceasing fluid flow therethrough. Upon contact with fluid, the interstitial voids of the material of the outer wall  220  and the closed end  210  gradually reduce to increasingly restrict air and fluid permeability, thus preventing bodily fluid fro entering the vacuum source through orifice  110 . 
         [0023]    While the invention has been described with reference to particular embodiments, it should be understood that various changes may be made and equivalents may be substituted for elements thereof without departing from the essential scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments, but that the invention shall include all embodiments falling within the scope of the following claims.