Patent Document

BACKGROUND TO THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a system for venting appliances which require venting during their operation, such as dishwashers and in particular to appliances which are designed for installation in surrounding furniture or joinery structures. 
         [0003]    2. Background to the Invention 
         [0004]    Automatic dishwashers typically operate a washing cycle which include a number of discrete operating stages, just as washing, rinsing and drying. During the drying stage, moist air within the wash chamber, remaining after the washing and rinsing stages, must be replaced with dry air. In order to replace the moist air with dry air, the moist air must have a means of escape from the wash chamber. This is achieved through a venting system, connecting the wash chamber with the exterior of the appliance. 
         [0005]    Venting systems typically comprise a venting conduit extending between the wash chamber and the outer wrapper of the dishwasher. The venting conduit often includes at least one valve which can be actively or passively operated to control venting. 
         [0006]    Increasingly, there is demand for appliances such as dishwashers to match surrounding kitchen furniture. These dishwashers must fit within a tight cavity formed by kitchen joinery and have a front face panel attached which matches the surrounding kitchen furniture. So called “integrated” dishwashers presents particular problems for venting during the drying stage. The dishwasher is surrounded in all sides by kitchen joinery preventing easy escape of moist air and intake of dry air. Furthermore, the desired clearance between the joinery and the dishwasher is decreasing, making efficient venting even more difficult. In the US door fronts often overlap leaving no space for venting, and some models of dishwasher prevent access to the kickstrap. To compound this problem, venting moist air into the space between the dishwasher and the joinery can cause condensation on the joinery which can damage the joinery. 
         [0007]    US2004/0163684 discloses a dishwasher with an automatically openable door. The door may be moved into an open position during a venting stage of the wash cycle. However, simply opening the door to provide venting removes control over the venting process. It is desirable to have full control over the rate, volume and mixing ratio of the exhausting air during venting. 
         [0008]    It would be desirable to provide a means for venting integrated automatic dishwashers that is efficient, controlled and does not damage surrounding joinery. 
         [0009]    Accordingly, it is an object of the present invention to provide a venting system which will go at least someway towards meeting the above desideratum or which will at least provide the public with a useful choice. 
       SUMMARY OF THE INVENTION 
       [0010]    According to a first aspect of the invention, an appliance comprises: 
         [0011]    a sealable chamber; 
         [0012]    a door for the sealable chamber, wherein in an opened position the door allows access to the chamber; and 
         [0013]    a venting system for allowing air to escape from the sealable chamber when the door is in a closed position, 
         [0014]    wherein the venting system includes a vent flap, the vent flap moveable from a closed position sealing the vent system to an open position allowing air to escape. 
         [0015]    Preferably, the vent flap forms at least part of the exterior surface of the appliance. Preferably, the vent flap forms part of the door. Preferably, in an open position the vent flap extends exteriorly of the door. 
         [0016]    Preferably, the appliance is adapted for placement in joinery structure or kitchen furniture. 
         [0017]    Preferably, the vent flap is tiltable between an open position and a closed position. Alternatively, the vent flap could undergo translational motion between an open position and a closed position. 
         [0018]    Preferably, the appliance further includes an actuator for moving the vent flap between the closed position and the open position. The appliance may also include a biasing element connected to the vent flap, for biasing the vent flap into the closed position. 
         [0019]    Preferably, the appliance includes a controller for controlling the operation of the appliance. 
         [0020]    Preferably, the controller is connected to the actuator, in use the controller controlling the actuator in accordance with an operating cycle of the appliance. 
         [0021]    Preferably, the venting system includes a mixing chamber for mixing air from the chamber with external air, in order to control the moisture content of the air exiting the venting system. Preferably, the venting system includes a variable speed fan. The variable speed fan may be connected to the controller. 
         [0022]    Preferably, the door is slideable between open position and a closed position and the sealable chamber is coupled to the door and is slideable with the door. 
         [0023]    Preferably, the appliance is a dishwasher. 
         [0024]    Preferably, the vent flap is actuated in accordance with the washing cycle of the dishwasher. 
         [0025]    Preferably, the door is adapted to receive an exterior face panel coupled to the vent flap wherein the vent flap moves the exterior face panel. 
         [0026]    According to a second aspect of the invention, a dishwasher comprises: 
         [0027]    a sealable chamber; 
         [0028]    a door for the sealable chamber, wherein in an opened position the door allows access to the chamber; and 
         [0029]    a venting system for allowing air to escape from the sealable chamber when the door is in a closed position, 
         [0030]    wherein the venting system includes a vent flap, the vent flap moveable from a closed position sealing the vent system to an open position allowing air to escape. 
         [0031]    Preferably, the dishwasher is a drawer type dishwasher. 
         [0032]    According to a third aspect of the invention, there is provided a venting system for an appliance having a sealable chamber, wherein the venting system allows air to escape from the sealable chamber when the appliance is in a closed configuration, and 
         [0033]    wherein the venting system includes a vent flap on an exterior surface of a door of the appliance, the vent flap moveable from a closed position sealing the vent system to an open position allowing the air to escape. 
         [0034]    According to a fourth aspect of the invention, a method for venting an appliance comprises the step of moving a vent flap from a closed position to an open position, wherein the vent flap forms part of the exterior surface of the door of the appliance and wherein the door remains in a closed position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0035]    Embodiments of the invention are now described, by way of example only, with reference to the drawings in which: 
           [0036]      FIG. 1  is a schematic illustration of a dishwasher in accordance with the present invention. 
           [0037]      FIG. 2   a  shows the dishwasher of  FIG. 1  with the vent flap in an open position. 
           [0038]      FIG. 2   b  shows an alternative embodiment of a dishwasher with the vent flap in an open position. 
           [0039]      FIG. 3  shows a hinge for the vent flap in accordance with a first example of the present invention. 
           [0040]      FIG. 4  shows a linkage arrangement for the vent flap in accordance with a second example of the present invention. 
           [0041]      FIG. 5  shows a cam arrangement for the vent flap in accordance with a third example of the present invention. 
           [0042]      FIG. 6  shows detail of an actuator mechanism that for the vent flap in accordance with an example of the present invention. 
           [0043]      FIG. 7  is a flow chart illustrating the control of a venting system in accordance with the present invention. 
           [0044]      FIG. 8  shows an integrated drawer type dishwasher in various configurations in accordance with the present invention. 
           [0045]      FIG. 9  shows an integrated oven in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0046]    The present invention provides a vent system for an appliance, such as an automatic domestic dishwasher.  FIG. 1  is a schematic cross section of a dishwasher. The dishwasher of  FIG. 1  is of the slideable drawer type disclosed in WO93/12706, the contents of which are incorporated herein by reference. The dishwasher may be of the “cabinetless” type, suitable for integrated installation, as described in WO01/26532, the contents of which are also incorporated herein by reference. Whilst the following description refers to a drawer type dishwasher, the present invention is applicable to conventional hinged door dishwashers and to other types of appliance, such as ovens, clothes driers and refrigerators. 
         [0047]    The dishwasher comprises a wash chamber  10  and a door assembly  12 . The door assembly may include electronics and a user interface to allow a user to programme the dishwasher but for clarity these are not shown. In a drawer type dishwasher as illustrated in  FIG. 1 , the door assembly is fixed to the wash chamber and is slideable with the wash chamber to an open position in which the wash chamber can be accessed from above. The door includes a vent flap  11  which is moveable to an open position to provide for venting of the wash chamber, while the dishwasher remains in a closed position, so that the wash chamber remains substantially sealed. 
         [0048]      FIG. 2   a  shows the dishwasher of  FIG. 1  with the vent flap in an open position and the door assembly is in a closed position. The vent flap is connected to a front face panel  14  and preferably covers the entire door. This allows the dishwasher door to be simply covered with a unitary cabinet door to match surrounding kitchen furniture, while allowing the vent flap  11  to operate. However, it should be recognized that a front face panel is not necessary and the vent flap  11  can be made aesthetically pleasing itself. 
         [0049]    Both  FIG. 1  and  FIG. 2   a  illustrate the basic features of a vent system in accordance with one example of the present invention. The dishwasher includes an exit conduit  16  for air in the wash chamber  10 . The wash chamber consists of a tub  15  and a lid  17 . Air in the wash chamber  10  is sucked out through the exit conduit  16  when fan  18  is operated. The fan  18  is located in a mixing chamber  20 . Moist air from the wash chamber is mixed with dry air in the mixing chamber. The dry air enters the mixing chamber via chassis air inlet  22 . Chassis air is ambient air that is present in the space surrounding the wash chamber. Air can enter the chassis space through various openings in the chassis of the dishwasher but principally will enter the chassis space when the vent flap  11  is in the open position. The mixture of moist wash chamber air and dry chassis air is driven through exhaust duct  24  by the fan  18  and out into the external space adjacent the dishwasher door. The exit conduit or exhaust duct may include one or more valves to prevent ingress or egress of air from and to the wash chamber during the wash cycle. 
         [0050]    The air sucked out of the wash chamber  10  by fan  18  is replaced by dry chassis air. The dry chassis air enters the wash chamber through air inlet  26 . The air inlet  24  may include a valve which can be actively or passively controlled or the air inlet may be of a labyrinthine configuration to prevent egress of air from the wash chamber via the inlet  26 . 
         [0051]    The exhaust duct  24  is shown in  FIGS. 1 and 2   a  as moving with the vent flap, the end of the exhaust duct being obstructed by the door structure in a closed position. Alternatively, as shown in  FIG. 2   b,  the exhaust duct  28  may be stationary within the door structure, the end of the exhaust duct  28  being obstructed by the vent flap  11  when the vent flap is in a closed position and unobstructed when the vent flap is in an open position. 
         [0052]    There are many possible mechanisms that can be used to attach the vent flap to the appliance.  FIG. 3  illustrates a simple hinge connecting the vent flap  11  to the body of the door assembly  12 .  FIG. 3   a  shows the flap in a closed position and  FIG. 3   b  shows the flap in an open position. A pair of hinges  30  could be placed on opposite sides of the flap  11 . The hinges could be placed on any edge of the vent flap to allow the vent flap to tilt between a closed position and an open position. 
         [0053]      FIG. 4  illustrates a link mechanism connecting the vent flap  11  to the rest of the door assembly  12  as an alternative. The link mechanism comprises a pair of link members  40  of unequal length.  FIG. 4   a  shows the vent flap in a closed position and  FIG. 4   b  shows the flap in an open position. Pushing the vent flap outwardly causes the vent flap to pivot out and down and pulling the vent flap inwardly causes the flap to pivot up and in. 
         [0054]      FIG. 5  illustrates a further alternative, a camming arrangement, for opening the vent flap. 
         [0055]      FIG. 5   a  shows the flap in a closed position and  FIG. 5   b  shows the flap in an open position. Two channels  50  are provided in each side of the body of the door assembly  12 . Corresponding cams  51  attached to the vent flap  11  are located in the channels  50 . A pair of hinges  52  is provided at the top of the vent flap  11 . Pushing the vent flap  11  outward or pulling it inward causes the cams  51  to slide in the channels  50 . The channels can be shaped to provide for a desired motion of the vent flap. 
         [0056]    An alternative connection for the vent flap  11  is to mount it on a pair of sliders. The vent flap is translatable on sliders from a closed position to an open position and back to a closed position. 
         [0057]      FIG. 6  shows detail of an actuator mechanism that is used to operate the opening and closing of the vent flap.  FIG. 6   a  shows the vent flap  14  in an open position. An actuator mechanism  60 ,  62  is mounted centrally at the base of the door assembly  12 . The actuator mechanism comprises a DC motor  60  and an actuator rod  62 . A DC motor is used in this example, but it will be appreciated that there are a number of alternatives, such as an AC motor, a solenoid and a wax actuator. It is also possible to use more than one actuating means, for example two symmetrically mounted DC motors. 
         [0058]    The DC motor is used to drive the actuator rod using a rack and pinion type coupling. The actuator rod  62  contacts the vent flap  14  and when driven towards the exterior of the appliance causes the vent flap to move to an open position. The vent flap is connected to the appliance door by a simple hinge  30  in this example.  FIG. 6   b  shows the vent flap in a closed position. The actuator rod is withdrawn into the body of the appliance, underneath the wash chamber  10 .  FIG. 6   c  shows biasing means  64 ,  66  for biasing the vent flap in a closed position.  FIG. 6   c  shows the rear side of the door  12 . The DC motor is mounted centrally at the base of the door. The vent flap is attached to a pair of tension springs  66  via wires  64  passing through the door. When the vent flap is moved to an open position via the action of the actuator rod  62 , the springs are extended and under tension. As the actuator rod  62  is withdrawn the action of the springs  66  forces the vent flap  12  to remain in contact with the actuator rod  62  until the closed position is reached as shown in  FIG. 6   b.  The DC motor is connected to and controlled by a controller or microprocessor  68  which controls the operation of the dishwasher 
         [0059]    The rate of venting of the wash chamber can be controlled by altering the speed of the fan  18 . The inlets  16 ,  22  to the mixing chamber  20  may be provided with movable parts, such as controllable valves, in order to control the moisture content of the air exiting the venting system via exhaust duct  24 . 
         [0060]    Venting is carried out during a drying stage of the dishwasher cycle. The dishwasher door remains in a closed position during the venting stage and the wash chamber remains substantially sealed. The venting flap is in a closed position when the dishwasher is not operating and during various stages of the dishwasher cycle. The vent flap is automatically opened at the appropriate stage in the wash cycle. The dishwasher cycle is electronically controlled by a programmed microcomputer. The microcomputer is connected to the vent flap opening mechanism and controls the opening and closing of the vent flap. 
         [0061]      FIG. 7  is a flow diagram showing the operation of the venting system during the operation cycle of a drawer type dishwasher. The operation cycle starts at step  700 . After the wash cycle stages of pre-wash, wash and rinse, a drain step  705  takes place. After the wash chamber has been drained, the vent flap is pushed out by the actuator at step  710 . The drying cycle then starts with the fan turned on to suck air out of the wash chamber at step  715 . 
         [0062]    It may be possible to stop or pause the operation of the dishwasher during the drying cycle. This can be achieved by pressing a stop/power button or pause button respectively. The option for pressing the stop button is shown in box  720  and the option for the pause button in box  725 . If neither the stop/power button nor the pause button is pressed, then the drying cycle completes after a predetermined time and the fan is switched off, indicated by step  730 . After the drying cycle is completed, the actuator is pulled in and the vent flap returns to the closed position at step  735 . Following retraction of the vent flap at step  740  the lid of the wash chamber is raised to allow the chamber to be withdrawn from the surrounding cabinetry. The operation cycle is then at an end, at indicated at step  745 . 
         [0063]    If the stop/power button is pressed during the drying cycle the fan is switched off, as indicated at step  750 . The vent flap is then returned to the closed position at step  755 , the lid of the wash chamber raised at step  760  and the wash cycle is then at an end at step  765 . As soon as the lid is raised the wash chamber can be withdrawn to provide access to its contents. 
         [0064]    If the pause button is pressed during the drying cycle then the fan is stopped, as indicated in step  770 . The vent flap is then moved to the closed position at step  775 , the wash chamber lid is raised at step  780  and the wash chamber can be withdrawn. Until the drying cycle is restarted by depression of the pause button nothing further happens, as indicated at step  790 . If the drying cycle is restarted at step  785  then, if the wash chamber is fully retracted, the lid is closed to seal the wash chamber at step  795 . The vent flap is pushed out at step  800  and the drying cycle is then resumed, with the fan switched in, at step  805 . The time remaining for the drying cycle is calculated using a timer in the controller. 
         [0065]      FIG. 8  shows an integrated dishwasher of the type described with reference to  FIGS. 1 and 2 .  FIG. 8   a  shows a set of kitchen cabinets. The dishwasher is placed in the centre of the top row. In a closed position, with the vent flap  14  closed, as shown in  FIG. 8   a,  the front face panel of the dishwasher matches and is flush with the surrounding cabinetry  80 . In a drying stage of the cycle of operation the vent flap  14  is tilted out to an open position, as shown in  FIG. 8   b.  In order to load and unload the dishwasher the door is pulled out with the wash chamber to provide access to the wash chamber from above, as shown in  FIG. 8   c.    
         [0066]      FIG. 9  shows an integrated oven in accordance with the present invention. Two types of oven are illustrated, a conventional hinged door oven and a drawer type oven.  FIG. 9   a  shows the oven door and vent flap in a closed position. The front face panel of the oven  93  matches the surrounding cabinetry.  FIG. 9   b  shows the vent flap in an open position. The vent flap is connected to the front face panel and is provided with an exhaust outlet  94  analogous to the exhaust duct of the dishwasher previously described.  FIG. 9   c  shows a conventional type oven with the door  91  in an open position. The vent flap  92  and the door  91  move together to allow for access to the oven chamber.  FIG. 9   d  shows a drawer type oven in a open position. Again the vent flap  92  and the door  91  move in unison to allow for access to the oven chamber. The same type of actuation can be used for the vent flap for the oven as for a dishwasher. 
         [0067]    The venting system of the present invention allows for controlled venting during the operation of an integrated appliance, such as a dishwasher, oven, refrigerator or clothes drier, without relying on there being sufficient space between the appliance and the surrounding furniture. The invention therefore allows appliances to fit tightly into cavities in furniture without compromising performance and without damaging the furniture during operation. It is particularly suited to drawer type dishwashers in which venting cannot be performed via a kickstrap near to the floor. Furthermore, the venting system of the present invention allows the front of the appliance to match surrounding furniture and in operation is elegant and unobtrusive.

Technology Category: d