Abstract:
A vacuum cleaner for collecting liquid material is capable of continuously operating while periodically discharging liquid from an outlet. The vacuum cleaner includes a tank having first and second chambers and divided by an intermediate apertured wall and a vent located on the second chamber. A pressure responsive drain valve member is associated with a tank outlet. A pressure responsive control valve member associated with the aperture having a normally open position in which the liquid material is allowed to flow through and having a closed position to close off the aperture when a high liquid level is present in the second chamber. The vent reduces the partial vacuum level in the second chamber, thereby to discharge liquid material from the second chamber through the outlet. A reset assembly is provided for reestablishing the partial vacuum level in the tank second chamber.

Description:
FIELD OF THE INVENTION 
     The present invention relates to vacuum cleaners, and more particularly to wet/dry vacuum cleaners. 
     BACKGROUND ART 
     Tank-type vacuum cleaners are capable of receiving dry materials, such as debris or dirt, as well as liquids. Such vacuum cleaners typically include an air impeller disposed inside an air impeller housing that is in fluid communication with an interior of the tank, thereby to create a low pressure area in the tank for vacuuming the dry and liquid materials. A motor is operatively coupled to the air impeller. 
     In all currently known wet/dry vacuum cleaners, the impeller must be shut off at some point in order to drain liquid from the tank. Some conventional vacuum cleaners have an enclosure in which the air impeller and motor are housed. The enclosure is removably attached to an upper, open end of the tank. To empty liquid from the tank, the impeller motor must be turned off and the enclosure removed from the tank before the tank may be tipped to dump liquid from the open end of the tank. 
     In other vacuum cleaners, the tank has an outlet drain formed near a bottom end of the tank that is closed off with a plug during vacuuming. When liquid is to be discharged from the tank, the plug is removed. The impeller motor must again be turned off to raise the pressure inside the tank, or else the liquid will not completely discharge from the tank. 
     It is also known to provide a pump with the vacuum cleaner for emptying the tank, such as in the vacuum cleaner described in commonly assigned U.S. Pat. No. 5,850,668. The pump and air impeller may be operated simultaneously, but the rate at which the impeller pulls liquid into the tank is typically higher than the rate at which the pump discharges liquid out of the tank. When the amount of liquid to be vacuumed is somewhat greater than the tank capacity, the tank ultimately becomes full. Consequently, the impeller and pump must be switched off for manual emptying of the tank or the vacuum cleaner must be operated without additional liquid entering the tank until the pump sufficiently empties the tank. Applications in which the volume of liquid to be vacuumed exceeds tank capacity include draining swimming pools or small ponds and removing water from flooded basements. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  is a schematic side elevation view, in cross-section, of a vacuum cleaner in accordance with the teachings of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     A vacuum cleaner  10  in accordance with the teachings of the present invention is illustrated at FIG.  1 . The vacuum cleaner  10  includes a tank  12  and an upper vacuum assembly, indicated generally at  14 . The tank  12  includes a pair of handles (not shown), which may be used to assist the user in lifting and moving the vacuum cleaner  10 . The tank  12  further defines an inlet  18  that may be fitted with a vacuum hose (not depicted) for applying suction at desired locations. 
     The upper vacuum assembly  14  includes a lid  20  releasably attached to the tank  12 . The lid  20  carries a motor housing  22  enclosing a motor  26 . The lid  20  makes up the bottom of the upper vacuum assembly  14  and may carry one or more latches (not shown) for attaching the upper vacuum assembly  14  to the tank  12 . When a user wishes to connect the upper vacuum assembly  14  to the tank  12 , the user positions the upper vacuum assembly  14  above the tank  12 , aligns the latches with latch recesses (not shown) formed in the tank, lowers the upper vacuum assembly  14  until the lid  20  rests on top of the tank  12 , and then, fastens the latches to the tank  12 . 
     Disposed in the upper vacuum assembly  14 , among other things, is an air impeller assembly  30 . The air impeller assembly  30  includes an impeller housing  32  having an opening in fluid communication with the tank  12  and an air impeller  24  disposed inside the air impeller housing  32 . A motor shaft  38  extends from the motor  26  to the impeller  24 . If desired, the vacuum cleaner  10  may alternatively use multiple air impellers. 
     The upper vacuum assembly  14  also includes a filter cage  40  extending downwardly from the lid  20 . The filter cage  40  may be integrally formed with or fastened to the lid  20 . The air impeller assembly  30  is in fluid communication with the filter cage  40  so that the air impeller  24  draws air through the filter cage  40 . The filter cage  40  includes several braces  42  that support a bottom plate  44 . One or more filters (not shown) may surround the circumference of the filter cage  40  as needed during dry and wet pickup. A ball float  46  is disposed in the filter cage  40  for closing off fluid communication between air impeller housing  32  and the filter cage  40  in response to a high liquid level in the tank  12 , as is generally known in the art. 
     The tank  12  is divided into first and second chambers. As shown in  FIG. 1 , an intermediate wall  50  divides the tank  12  into an upper chamber  52  and a lower chamber  54 . An aperture  80  is formed in the intermediate wall  50  to allow fluid communication between the upper chamber  52  and the lower chamber  54 . The intermediate wall  50  is positioned so that the inlet  18  discharges vacuumed liquid directly into the upper chamber  52 . 
     An outlet  58  is formed in a lower part of the tank  12  to allow fluid communication between the lower chamber  54  and atmosphere. A drain valve member in the form of a cap  60  is held adjacent the outlet  58  by a connecting strip  62 . In a closed position, the cap  60  substantially overlies the outlet  58  to prevent fluid flow therethrough. The outlet  58  and cap  60  are oriented so that the cap  60  is normally in the closed position under the force of gravity. The cap  60  is pressure responsive so that when a partial vacuum pressure is present in the lower chamber  54 , the cap  60  is pulled to the closed position to engage and seal with the outlet  58 . In the absence of (or reduction in) the partial vacuum pressure, the cap  60  is free to move away from the outlet  58  to an open position, in which fluid communication is established between the lower chamber  54  and atmosphere. The force for pushing the cap  62  to the open position may be the pressure of liquid collected in the lower chamber  54 . 
     A control valve member is provided for selectively establishing fluid communication between the upper and lower chambers  52 ,  54 . In the illustrated embodiment, the control valve member is provided in the form of a ball float  82  positioned adjacent the aperture  80  and disposed inside a cage  84 . The ball float  82  is buoyant so that a rising liquid level in the lower chamber  54  will raise the ball float  82  toward the aperture  80 . Accordingly, the ball float  82  is moveable between a closed position, in which the ball float  82  engages the aperture  80 , and an open position, in which the ball float  82  is spaced from the aperture  80 . When moved to the closed position by the rising liquid level in the lower chamber  54 , the ball float  82  is further held in the closed position by the partial vacuum pressure present in the upper chamber  52 . A vent  68  extends through the tank  12  to establish fluid communication between the lower chamber  54  and atmosphere. 
     A reset assembly is provided for re-establishing partial vacuum level in the lower chamber  54  once the lower chamber  54  is empty of liquid. In the illustrated embodiment, the reset assembly includes a reset aperture  56  formed in the intermediate wall  50  and a collar  66  attached to and extending downwardly from the intermediate wall  50 . The collar  66  completely surrounds the aperture  56  and has a lower edge sized to engage a stopper ball  64  disposed in the lower chamber  54 . A lever  70  is carried by a fulcrum support  72 , and has a first end coupled to the stopper ball  64  by a rod  74 . A second end of the lever  70  is coupled to a buoyant float  76 . The reset assembly is arranged so that the stopper ball  64  is normally in the closed position. In the illustrated embodiment, the stopper ball  64  and buoyant float  76  have substantially the same buoyancy and weight, and therefore the fulcrum support  72  is positioned closer to the first end of the lever  70  (nearer the stopper ball  64 ) to ensure that the stopper ball  64  is in the normally closed position. 
     When the ball float  82  is in the closed position, liquid will begin to collect in the upper chamber  52 . Eventually, the rising liquid level in the upper chamber  52  will drive the buoyant float  76  upward, so that the rod  74  attached to the opposite end of the lever is pushed downward. The downward force generated by the lever  70  will eventually overcome the partial vacuum force holding the stopper ball  64  in the closed position, thereby pushing the stopper ball  64  to the open position. 
     During initial operation of the vacuum cleaner  10 , the upper and lower chambers  52 ,  54  are empty of liquid so that the ball float  82  is in the open position, and the stopper ball  64  is in the closed position. As a result, partial vacuum generated by the air impeller assembly  30  is present in both the upper and lower chambers  52 ,  54  via the aperture  80  to generate a closing force on the cap  60 . The ball float  82  remains in the open position as water begins to collect in the lower chamber  54 . Once a sufficient liquid level accumulates in the lower chamber  54 , the ball float  82  begins to rise toward the closed position. When the ball float  82  is in the fully closed position, fluid communication between the upper chamber  52  and lower chamber  54  is cut off. The vent  68  communicates atmospheric pressure into the lower chamber  54 , thereby to reduce the partial vacuum pressure in the lower chamber  54  (i.e., the pressure in the lower chamber  54  increases). Once the pressure in the lower chamber  54  nears the atmospheric pressure, the liquid in the lower chamber  54  will push the cap  60  to at least a partially open position, thereby allowing the liquid in the lower chamber  54  to flow through the outlet  58 . 
     While liquid drains from the outlet  58 , additional liquid collects in the upper chamber  52 . As the liquid level in the upper chamber  52  rises, it creates the upward force on the buoyant float  76 . The magnitude of the upward force on the buoyant float  76  eventually overcomes the partial vacuum force holding the stopper ball  64  in the closed position, so that the lever  70  and rod  74  push the stopper ball  64  to the open position. At this point, fluid communication between the upper chamber  52  and lower chamber  54  is re-established, and the lower chamber  54  is again placed under partial vacuum pressure. The lower pressure in the lower chamber  54  pulls the cap  60  closed and returns the ball float  82  to the open position. Liquid from the upper chamber  52  is allowed to flow through the aperture  80  to again fill the lower chamber  54 . This process may be repeated indefinitely to allow continuous operation of the vacuum cleaner  10  while periodically discharging liquid from the lower chamber  54 . 
     While the illustrated embodiment shows a single control valve member, it will be appreciated that multiple control valve members may be provided to increase the capacity and/or rate of flow between the upper and lower chambers  52 ,  54 . Furthermore, the size of the aperture  80  and stopper ball  82  may be varied according to the capacity and/or rate of desired fluid flow. 
     The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, as modifications would be obvious to those skilled in the art.