Washing machines

Abstract

A washer/drier with a new pump arrangement. In the new arrangement a first pump is adapted to pump washing liquid to the treatment chamber, and a second pump is provided which is adapted to pump water through a venturi vacuum forming device for establishing below ambient pressure in the treatment chamber, typically during a spin-drying cycle. The second pump can be operated selectively to pump water to the treatment chamber for rinsing articles therein or to supply water to the venturi vacuum forming device. The treatment chamber comprises an elliptical drum having perforated wall regions at opposite internal ends thereof to the rear of which liquid is supplied or through which it is drawn out from during washing and rinsing, and through which air is drawn during the drying cycle.

1 . A washer/drier of the type described, in which there is provided a first pump which is adapted to pump washing liquid to the treatment chamber, and a second pump which is adapted to pump water through a venturi vacuum forming device for establishing below ambient pressure in the treatment chamber during a spin-drying cycle.  
     
     
         2 . A washer/drier as claimed in  claim 1 , wherein the second pump operates selectively to pump water to the treatment chamber for rinsing articles therein or to supply water to the venturi vacuum forming device.  
     
     
         3 . A washer/drier of the type described or as claimed in  claim 1  or  2 , wherein the treatment chamber comprises an elliptical drum having perforated wall regions at opposite internal ends thereof to form cavities or voids to which liquid is supplied or drawn out from during washing and rinsing, and through which air is drawn during the drying cycle.  
     
     
         4 . A washer/drier of the type described or as claimed in  claim 1  or  2 , wherein an inner shell is provided within the elliptical drum spaced from the solid outer drum wall to form a continuous cavity or void around the drum, and perforations are provided in diametrically opposite regions of the inner shell.  
     
     
         5 . A washer/drier as claimed in  claim 4  wherein liquid is pumped to the cavity or void under pressure so as to be forced into the drum through the perforations.  
     
     
         6 . A washer/drier as claimed in  claim 3 ,  4 , or  5  wherein a venturi vacuum forming device communicates with the or each cavity or void to withdraw air from the drum during a vacuum assisted drying cycle.  
     
     
         7 . A washer/drier as claimed in any of  claims 4  to  6  wherein the inner shell is perforated over the whole of its surface.  
     
     
         8 . A washer/drier as claimed in  claim 3  or  4  wherein the drum is formed from two parallel generally elliptical flat side panels, spaced apart by and joined to opposite parallel edges of an outer wall of sheet metal, bent to conform to the generally elliptical shape of the panels, and two panels of perforated sheet metal are fitted to and extend internally across the curved end regions of the elliptical drum between the two parallel side panels, to define internal voids at opposite ends of the elliptical drum, or an inner metal sheet shaped to conform to the outer wall but spaced internally therefrom to define a continuous void therebetween, is provided, with perforations at least in the end regions.  
     
     
         9 . A washer/drier as claimed in  claim 8  wherein a passage for communicating with the or each void is formed by means of an inner plate welded or otherwise bonded to the internal face of one of the flat side walls of the drum, and a central region thereof is deformed to create a reservoir, and an elongate ridge is formed in the plate which extends on opposite sides of the reservoir formation, so that with the plate fitted flush to the flat inside surface of the drum wall, the ridge creates ducts between the reservoir and opposite ends of the drum through which fluid can pass.  
     
     
         10 . A washer/drier as claimed in  claim 9  wherein a central circular opening is provided in the side wall of the drum which communicates with a co-axial tube to provide a fluid path from the reservoir.  
     
     
         11 . A washer/drier as claimed in  claim 10  wherein a rotary seal is provided between the tube and the opening to allow for relative movement therebetween.  
     
     
         12 . A washer/drier as claimed in  claim 11  wherein the ducts communicate between the reservoir and the spaces behind the perforations at opposite ends of the drum.  
     
     
         13 . A washer/drier as claimed in any of  claims 3  to  12  wherein the drum is located within a housing, with the two flat sides of the drum spaced from front and back walls of the housing, the front housing wall includes an access opening, and the flat side wall of the drum at the front of the housing includes a large circular opening which registers with the access opening in the housing wall to enable articles to be passed axially into and out of the drum.  
     
     
         14 . A washer/drier as claimed in  claim 13  further comprising a support frame for rotatably supporting the drum in the housing, and the drum opening includes an axially extending peripheral lip which protrudes axially through a circular opening in the support frame which also registers with the access opening, and a radial bearing is secured within the opening in the support frame, with its outer race secured to the support frame and the inner race secured to the lip around the opening in the drum, to rotatably support the drum in the support frame.  
     
     
         15 . A washer/drier as claimed in  claim 13  or  14  wherein a door is hinged to the housing, for closing the access opening.  
     
     
         16 . A washer/drier as claimed in  claim 15  wherein two annular seals are provided, a first of which resists the passage of air or liquid from the drum and the second of which resists the passage of air into the drum when the pressure in the drumis reduced below atmospheric.  
     
     
         17 . A washer/drier as claimed in  claim 16  in so far as it is dependent from  claim 14  wherein the lip protrudes axially beyond the bearing to provide a cylindrical seating for one of the annular seals, and the other annular seal co-operates with the inside of the door.  
     
     
         18 . A washer/drier of the type described or as claimed in  claim 1  or  claim 2  wherein the treatment chamber is an elliptical drum rotatably mounted in the housing, an opening is provided in one of its curved ends and another opening is provided in the housing, which registers with the opening in the drum at one rotational position of the latter, to allow access to the interior of the drum, and the opening in the drum is sealable to retain liquid in the drum for washing and rinsing when it is rotated, and the opening in the housing is closed by a conventional door.  
     
     
         19 . A washer/drier as claimed in  claim 18  wherein the drum is rotated about a horizontal axis midway between the two geometric centres of its elliptical shape the housing is a rectilinear cabinet, and the access opening is in the upper face of the housing.  
     
     
         20 . A washer/drier as claimed in  claim 19  wherein sensing means and braking means is provided, so as always to stop the drum in a position in which the opening therein aligns with the access opening in the housing, so that articles can be inserted or withdrawn from above.  
     
     
         21 . A washer/drier as claimed in any of  claims 1  to  20  wherein the pump employed for pumping water to the vacuum forming venturi pump during the vacuum assisted spin-drying cycle is capable of delivering water at a pressure of 70-100 psi, so as to achieve a venturi vacuum of 25-26 inches of mercury.  
     
     
         22 . A washer/drier as claimed in any of  claims 1  to  20  wherein the pump employed to supply water to the venturi vacuum pump supplies the water thereto at a pressure of at least 170 psi so as to produce a vacuum of the order of 29 inches of mercury.  
     
     
         23 . A washer/drier as claimed in any of  claims 1  to  22  wherein the drum is rotated at speeds of the order of 50 rpm during washing and up to 2000 rpm during spin-drying cycles.