Patent Publication Number: US-6658901-B2

Title: Indication device for a laundry washing machine

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to an indication device for a laundry washing machine. The washing machine comprises a treatment chamber for laundry that is pressurized in order to treat the laundry with a cleaning agent. The chamber has an opening, which in the treatment position is covered by a door fixed to a surrounding housing and is sealed from the housing by means of a sealing arrangement. 
     Laundry washing machines of the type mentioned above are previously known and have been developed because of environmental reasons to replace chemical washing machines in which, for instance, trichloroethylene or perchloroethylene are used. In these alternative machines, a cleaning agent such as carbon dioxide is used in liquid state. However, there is a complication with respect to this technique since the washing chamber has to be under pressure during the treatment procedure. Machines of this type are described, for instance, in U.S. Pat. No. 5,267,455. 
     The sealing of the door, in particular the sealing device that is arranged around the fill opening of the machine, is often exposed to wear. Because of the high pressure, there is a risk for gas leakage from the treatment chamber, which would not be observed by people around the machine. 
     BRIEF SUMMARY OF THE INVENTION 
     The invention provides a simple and cost-effective sealing arrangement comprising an indication means intended to call upon the attention of people around a laundry washing machine that a gas leak from the treatment chamber has occurred. This is achieved by means of a device comprising a treatment chamber for laundry with an opening, which in a treatment position, is covered by a door fixed to a surrounding housing and is sealed from the housing by means of a sealing arrangement. The chamber is pressurized to treat laundry with a cleaning agent, and the sealing arrangement is provided with at least two gaskets surrounding the opening and forming an intermediate space. The space is arranged to communicate with the atmosphere via a channel such that a sound indication is achieved if there is gas leakage to the intermediate space. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An embodiment of the invention will now be described with reference to the accompanying figures in which: 
     FIG. 1 is a cross-sectional view of a machine with an embodiment of the invention, and 
     FIG. 2 is view of an enlargement of a section through part of the door portion of the machine in FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The laundry washing machine shown in FIG. 1 comprises a frame  10  supporting a pressure housing  11  that forms a treatment chamber  12  with a circular fill opening  13 . The chamber  12  encloses a drum  14  that is rotatably supported by means of a horizontal shaft extending through a rear wall of the chamber  12  and which is driven by an electric motor (not shown). The drum  14  has, in a conventional manner, an opening  15 , which is mainly as large as the fill opening  13  and coaxial with it. During the washing process, the fill opening  13  is covered by a door  16 , which via a hinge (not shown), is fastened to a flange portion  17  surrounding the opening of the front wall  18  of the housing  11 . 
     The door is sealed from the flange part  17  by means of a sealing arrangement comprising two concentric gaskets  19  and  20  designed as O-rings. The first O-ring  19  has a smaller diameter than the second O-ring  20 . Each O-rings is inserted into a groove  21  and  22 , respectively, in the door and is maintained in the groove because of the dovetail shape of the groove. An intermediate space  23  is located between the two O-rings and is via a channel or gas passage  24  connected to atmosphere. 
     The sealing arrangement operates in the following manner. When the door  16  is closed and pressurized gas, for instance, liquid carbon dioxide, has filled into the treatment chamber  12 , the inner gasket  19  seals the treatment chamber from the surroundings. Should any damage occur on the gasket  19 , gas will leak out into the space  23  and flow through the channel  24 . Since the channel is designed such that it also serves as a restriction for small amounts of gas leaking to the space  23 , a characteristic whistling sound occurs, thus, indicating for the surroundings that the sealing effect is unsatisfactory and that measurements should be taken to repair the fault. 
     The described sealing arrangement is not limited to the described use at the fill opening of a laundry washing machine, but may be used for other doors or details arranged in the wall of the treatment chamber. 
     While the invention has been described with reference to a specific embodiment, various changes may be made and equivalents may be substituted for elements thereof by those skilled in the art without departing from the scope of the invention. In addition, other modifications may be made to adapt a particular situation or method to the teachings of the invention without departing from the essential scope thereof. The present invention herein is not to be construed as being limited, except insofar as indicated in the appended claims.