Patent Publication Number: US-8533906-B2

Title: Vacuum cleaner with recirculated cooling air

Description:
FIELD OF THE DISCLOSURE 
     The present disclosure relates generally to vacuum cleaners and, more specifically, to a vacuum cleaner with recirculated cooling air. 
     BACKGROUND OF THE DISCLOSURE 
     A conventional upright vacuum cleaner includes a floor engaging main body or foot having a nozzle formed with a nozzle opening. An agitator is typically rotatably mounted within the nozzle, and a dirt duct is formed in the main body and communicates at one end with the nozzle and at an opposite end with vacuum-generating means, such as a motor-fan assembly. The motor-fan assembly typically communicates with a duct to draw a flow of dirt-laden working air through the main body and into a dirt collecting filter bag, which removes the dirt and allows substantially clean air to be returned to the environment through the walls of the filter bag. 
     The motor fan assembly typically includes a motor housing that encloses a motor. The motor rotatably drives a shaft to which a working fan is suitably coupled such that the working fan rotates with the shaft. As the motor rotates with the motor housing, heat is generated within the motor. To prevent overheating of the motor, a cooling fan is typically provided. In one example, the cooling fan is provided on an end of the shaft opposite the working fan. The cooling fan draws a stream of cooling air into the motor housing through a plurality of cooling air inlets often formed in the motor housing. The cooling air then flows across the motor and is expelled from the motor housing through one or more exhaust openings in the motor housing. The exhaust openings are often located at an end of the motor housing opposite the working air inlet. The cooling air prevents debris and other particles from passing through the motor, for example, when it exits the exhaust openings in the motor housing of a conventional vacuum cleaner. In U.S. Pat. No. 6,880,201, the cooling air can be directed along with the working air in the collection bag so that cooling air is filtered before being exhausted into the atmosphere. 
     In other vacuum cleaners, the working air is filtered before reaching the motor-fan assembly. Such designs are common in tank-type vacuum cleaners where working air enters a tank inlet, generally through a hose. The tank is under negative pressure through the operation of a motor-fan assembly that draws working air out of the tank. In order to reach the motor-fan assembly, the working air must pass through one or more filtering elements, such as a filter bag or cartridge filter, before passing through the fan and back out into the environment. Such vacuums are often referred to as clean-air designs since the working air has been “cleaned” before reaching the fan. If the bag or cartridge filter is made of HEPA materials, the working air is effectively receiving HEPA filtration before being exhausted to the environment. 
     Clean air designs may have cooling fans for cooling the motor. Typically, cooling air is drawn through the motor-fan housing through the motor and back out into the environment without filtration. The cooling air can have particulate material in it, for instance, created from the brushes in the motor&#39;s commutator, or simply from the environment when drawn into the housing by the cooling fan. Combining the cooling air with the working air adjacent the motor, such as is shown in U.S. Pat. No. 6,880,201, is not a viable solution since the working air in a clean-air design is already cleaned by the time it reaches the motor. 
     SUMMARY OF THE DISCLOSURE 
     A vacuum cleaner includes a receptacle having a working air inlet and an associated filter, the filter in communication with and downstream from the working air inlet. The vacuum cleaner further includes a housing containing a motor and having a cooling air outlet from the motor and a working air outlet, the working air outlet in communication with the working air inlet of the receptacle through a working air impeller, wherein cooling air is directed to the receptacle, and the cooling air passes through the filter before exiting the working air outlet of the housing. 
     Further, the filter of the vacuum cleaner may be in communication with and downstream from the cooling air outlet, and the cooling air outlet may be in communication with the working air inlet through a passageway in the housing. 
     In some cases, the receptacle may further include a hose fitting for receiving working air, and the cooling air merges with the working air at the hose fitting. Still further, the hose fitting may include an aperture for receiving the cooling air. In addition, the housing may include a duct for receiving cooling air, such that the duct is in communication with the aperture of the hose fitting and is directing the cooling air into the hose fitting. 
     Still further, after exiting the filter, the cooling air and working air may pass through a HEPA filter before passing through the working air outlet. In addition, the motor fits within the housing, the filter may capture any particles in the cooling air discharged by the motor, and the vacuum cleaner may be a wet-dry vacuum cleaner. 
     In another example, a wet-dry vacuum cleaner includes a receptacle having a working air inlet and an associated filter, the filter in communication with and downstream from the working air inlet, and a lid contacting the receptacle. The wet-dry vacuum cleaner further includes a housing connected to the lid and containing a motor, the housing having a cooling air outlet from the motor and a working air outlet, the working air outlet in communication with the working inlet of the receptacle through a working air impeller. In this example, the cooling air is directed to the receptacle, and cooling air passes through the filter before exiting the working air outlet of the housing. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a front perspective view of a vacuum cleaner of the present disclosure; 
         FIG. 2  is a side view of the vacuum cleaner of the present disclosure; 
         FIG. 3  is a back perspective view of the vacuum cleaner of the present disclosure; 
         FIG. 4  is an exploded view of the vacuum cleaner of the present disclosure; 
         FIG. 5  is a top, perspective view of a receptacle of the vacuum cleaner of the present disclosure; 
         FIG. 6  is a side sectional view of the vacuum cleaner of the present disclosure taken along the line A-A in  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     Referring now to  FIGS. 1-3 , a vacuum cleaner  10  of the present disclosure is illustrated. As illustrated in  FIG. 1 , the vacuum cleaner  10  includes a receptacle  12  having a working air inlet  14  and a motor housing  18  connected to a top portion of the receptacle  12 . The motor housing  18  receives or at least contacts a motor  20  ( FIGS. 4 and 6 ). In this example, the working air inlet  14  is disposed at a front end of the receptacle  12 . An upper housing  30  is connected to the motor housing  18  that covers at least the motor housing  18  and the receptacle  12 . A switch  11  is disposed on a top portion of the upper housing  30 . 
     Referring now to  FIG. 2 , a side perspective view of the vacuum cleaner  10  is illustrated. As shown therein, the motor housing  18  further includes a working air outlet  24  that is disposed at a rear end of the receptacle  12  opposite the working air inlet  14 . The motor housing  18  also includes a cooling air inlet  21  and a cooling air outlet  22  ( FIG. 6 ). The working air outlet  24  is in communication with the working air inlet  14  of the receptacle  12  through a working air impeller  26  ( FIG. 6 ). The working air outlet  24  of the receptacle  12  may have an elongate, rectangular shape, as illustrated in  FIG. 3 . As one of ordinary skill in the art can appreciate, the working air outlet  24  may take the form of a variety of other shapes, including, but not limited to, an oval or circle, for example. 
     Referring now to  FIG. 4 , an exploded view of the vacuum cleaner  10  of the present disclosure is illustrated. The receptacle  12  further includes an associated filter in the form of a filter bag  16  disposed therein. An additional filter  19  having a filter cap  19   a  is also disposed within the receptacle  12  adjacent the filter bag  16 . The additional filter  19  may take the form of a variety of filters, such as a HEPA filter, that are different than the conventional filter bag  16  associated with a typical vacuum cleaner receptacle  12 . In this example, a lid  17  having a cage  40  is connected to a top or open portion of the receptacle  12 , and the motor housing  18  is connected to the lid  17 . The lid  17  includes a latch  42 , and a float  44  is disposed within the cage  40 . The motor housing  18  includes a motor  20  and an impeller  26 . A baffle  28  is connected to a top portion of the motor housing  18 , and the upper housing  30  is placed over the baffle  28  and connected to the motor housing  18 , such that the upper housing  30  covers both the motor housing  18  and the receptacle  12 . The lid  17 , motor housing  18 , baffle  28  and upper housing  30  together form a housing assembly of the vacuum cleaner. 
     Referring now to  FIG. 5 , a side, perspective view of the receptacle  12  of the vacuum cleaner  10  of  FIGS. 1-4  is illustrated. The receptacle  12  further includes a hose fitting  32  disposed at one end of the receptacle  12 . More specifically, in this example, the hose fitting  32  is disposed outside the receptacle  12 . The hose fitting  32  receives working air from the working air inlet  14  and includes an aperture  34  for receiving cooling air from the cooling air outlet  22  as described in more detail below in connection with ( FIG. 6 ). A bag fitting  46  is connected to the hose fitting  32  and secures the filter bag  16  so that working air flowing through the hose  32  passes into the receptacle  12  and into the filter bag  16 . 
       FIG. 6  is a sectional view of the vacuum cleaner  10  of the present disclosure taken along the line A-A of  FIG. 2 . As illustrated therein, the filter bag  16  is in communication with and downstream from the cooling air outlet  22 , and the cooling air outlet  22  is in communication with the receptacle through the working air inlet  14  by a passageway  31 . This allows cooling air from the cooling air outlet  22  to merge with working air from the working air inlet  14  at the hose fitting  32 . More specifically, the aperture  34  of the hose fitting  32  receives cooling air from the cooling air outlet  22 , and the motor housing  18  further includes a duct  36  for receiving the cooling air. The duct  36  is in communication with the aperture  34  of the hose fitting  32  for receiving working air and directs the cooling air into the hose fitting  32  for receiving working air. Thus, as working air enters the working air inlet  14  through the vacuum created by the working impeller  26 , and cooling air exits the cooling air outlet  22 , the cooling air merges with the working air and together the cooling air and working air pass through the filter bag  16 . 
       FIG. 6  further illustrates the flow paths of both the cooling air and the working air as they both enter and exit the vacuum cleaner  10 . Specifically, cooling air enters the motor housing  18  through the cooling air inlet  21  and is drawn through the motor  20  (arrows A) by a cooling fan  23  disposed at a top portion of the motor housing  18 . While passing through the motor  20 , particles of dust and other debris from the motor  20 , for example, may enter the stream of cooling air. After passing through the motor  20 , the cooling air then passes through the motor housing  18  to the cooling air outlet  22  along a flow path within the motor housing  18  (arrows B) adjacent the upper housing  30 . 
     The cooling air then merges with the working air entering the working air inlet  14  and flowing through a working air flow path (arrows C), forming a pathway having both working air and cooling air (arrows BC). This dirt-laden working and cooling air (arrows BC) then flows through the filter bag  16  and, in this example, a HEPA filter  19  as well. While in this example both the filter bag  16  and the HEPA filter  19  capture debris particles in the working air and cooling air, in many cases only a single filter will be used. 
     After flowing through the filter bag  16  and HEPA filter  19 , the air is then routed through the cage  40  of the receptacle  12  and up along a flow path (arrows D) toward the impeller  26  of the motor housing  18  via the impeller  26 . Because the air has passed through at least the filter bag  16 , the air flowing through the flow path (arrows D) to the working air outlet  24  is free of dust and debris from both the motor and any outside particles before exiting into the atmosphere at the working air outlet  24 . 
     In this example, the vacuum cleaner  10  is a wet-dry vacuum. However, one of skill in the art will appreciate that various other vacuum cleaners may alternatively include the redirected cooling air features of the disclosure described above and recited in the claims, such that cooling air merges with working air and passes through a filter before exiting into the atmosphere. 
     While various embodiments have been described herein, it is understood that the appended claims are not intended to be limited thereto, and may include variations that are still within the literal or equivalent scope of the claims.