GB2181220A - Machine for washing and drying domestic laundry - Google Patents

Abstract

A machine for washing and drying domestic laundry comprises a cabinet (3) containing a stationary cylindrical tank (1) for holding washing liquor and a rotatable perforated drum (2) within the tank in which the laundry is washed and subsequently tumble-dried. For drying the laundry a stream of hot air produced by a fan (26) and heater (27) flows through a narrow duct (28) into the drum, the moist air leaving through an outlet (21) in the bottom of the tank which also serves for the removal of the dirty washing liquor. After being dried in a condenser (30) the air returned to the fan for recirculation in the machine. A small high-speed fan is used which delivers air at high pressure and velocity so that air ducts of small cross-section can be used. The fan and the heater are housed in a box which is attached to the back of the cabinet. With this arrangement, and the use of small-section air ducts, a standard washing machine can readily be converted into a washer/dryer. <IMAGE>

Description

SPECIFICATION Machine for washing and drying domestic laundry This invention relates to a machineforwashing and drying domestic laundry, comprising a cabinet containing a stationarytankfor holding washing liquor, a perforated drum within the tankfor holding laundry to be washed and subsequently dried in the drum, the drum being rotatable inside the tank about a horizontal axis, a fan and a heaterfor generating a stream of hotairfor drying the laundry, and ductsforconducting the hot airfrom the heater into the drum and forconducting awayfromthetanktheairwhich passes from the drum into the space between the drum andthetank via the perforations in the drum.

This air may be exhausted to the exterior of the cab inet or it may be cooled to remove moisture from it by condensation and then be returned to the fan for recirculation in the machine. These washing and drying machines are often referred to as "washer/ dryers".

The market for washer/dryers is at present quite small and this fact, coupled with the high costofdeveloping special machines, makes it an attractive proposition to convert an existing washing machine into a washer dryer. It is an object of the invention to provide a construction which will enable such conversion to be carried out with minimal modification of the existing machine.

According to the invention there is provided a machineforwashing and drying domestic laundry, comprising a cabinet containing a stationarytankfor holding washing liquor, a perforated drum within the tankforholding laundrytobewashedandsubsequ- ently dried in the drum,the drum being rotatable inside the tank about a horizontal axis, a fan and a hea terforgenerating a stream of hot airfordrying the laundry, and ducts for conducting the hot air from the heater into the drum and for conducting away from thetankthe air which passes from the drum into the space between the drum andthetank via the per- forations in the drum, characterised in that the fan is a high-speed fan and in thatthefan, a motorfordriving the fan, and the heater are all housed in a box which is mounted on the outside ofthe back ofthe cabinet.

With a high-speed fan a high pressure is dev eloped, so that the heater may have a small heater chamber and air ducts of small cross-sectional area.

Such ducts can readily be accommodated in the limited space available between the internal components of the machine. The high pressure of the air system also allows the air, at high velocity, to leave thetankthrough the relatively small hole which is normally provided in the bottom ofthetankforthe removal of the dirty washing liquor and rinsing water. Due to the small size of the fan and the heater chamber, the box in which thefan and heater are housed on the back of the cabinet adds very little to the depth ofthe machine.With the construction according to the invention the only modification required to a standard washing machine to enable itto be converted into a washer/dryer is the provision of a large hole in the rearwall ofthecabinetfortheoutlet duct from the heater and some holes to receive screws or bolts forth attachment of the box to the back of the cabinet. An added advantage of locating the fan, the fan motorandthe heater in a boxonthe back of the cabinet is the resulting accessibility of these components for maintenance or repair.

In an embodiment of the invention which comprises a condenser for removing moisture from the airconductedawayfromthetank,a pipe being provided forfeeding cooling waterto the condenser, and ducts being provided for conducting the airfrom the tankto the condenser and from the condensertothe inlet ofthe fan, a valvefor controlling the waterfeed to the condenserthrough said pipe may be housed in said box.

The condenser may conveniently be mounted ben eath said box with the feed pipe for the cooling water and the duct for conducting the airfrom the condenserto the fan passing through the bottom ofthe box.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic part-sectional side elevation of a washing and drying machine in which the air is recirculated via a condenser, the cabinet of the machine, with the exception of the frontwall, being omitted forthe sake ofclarity, Figure 2 is a diagrammatic rear elevation of the machine shown in Figure 1, with the whole ofthe cabinet omitted, Figure 3 is a schematic rear elevation of a washing and drying machine according to an embodiment of the invention in which the air is recirculated as in the arrangement shown in Figures 1 and 2, Figure 4 is a side elevation of the machine shown in Figure 3, Figure 5 is a plan view of the interior of the machine shown in Figures 3 and 4with the box con tainingthefanand heater omitted and showingthe ductthrough which hot air is conducted from the heater into the drum, Figure 6 is a sectional front elevation of the upper part of the machine shown in Figures3 and 4, the section being taken on the line VI-VI in Figure 5, Figure 7 is a fragmentary sectional view taken on the lineVIl-VIl in Figure Sand drawn to a larger scale, Figure8is a plan view ofthe hot-air duct shown in Figures 5 to 7, Figure 9 is a longitudinal sectional view ofthe duct taken on the line IX-IX in Figure 8, and Figure 10 is an end view of the duct looking inthe direction ofthearrowXin Figure 8.

The washing and drying machine shown dia grammatically in Figures 1 and 2 com prises a stationarytank 1 of cylindrical form for holding washing liquor and within the tank a rotatable perforated drum 2 for holding the laundry to be washed and dried. The tank 1 is suspended in a cabinet, of which the front wall is shown at 3 in Figure 1. 1.The tank is arranged with its axis disposed horizontally, and the drum is rotatably supported inthetankcoaxilly therewith by a shaft 4 which projects from the rear end wall 5 of the drum and isjournalled in a bearing (not shown) in the rear end wall 6 of thetank.Outside the tank the shaft 4 receives drive from an electric motor by which the drum 2 can be rotated atlow speed in alternate directions during the washing and tumble-drying operations and at high speed in one direction only during the spinning operation. The motor is notshown in Figures 1 and 2 but Figure 3 shows a motor 7 which drives the drum of the machine shown in that figure through a belt 8 and a pulley 9 keyed on the shaft 4 of the drum.

The drum 2 has perforations 10 (Figure 1) in its cylindrical wall 11 and a large circular central opening 12 in its front end wall 13 through which the laun drycan be loaded intothe drum. Thetankl hasa similar opening 14in its front end wall 15 and a corresponding opening is provided in the front wall 3 of the cabinet, the three openings being coaxial with one another. Aflexible annular seal 17,forexample, a rubber bellows seal, is fixed to the front end wall 15 ofthetank 1 around the opening 14therein and to the frontwall 3 of the cabinet around the corresponding opening in this wall.For closing this opening a hinged porthole door 18 is provided on the front wall of the cabinet, the door being arranged to seat in a water- and air4ight manner on a rim ofthe seal 17 at the front edge of the seal, and the construction of this seal and the door 18 being such as to leave an an nularspace 19 between the seal 17 and a transparent portion 20 ofthe door which has a frusto-conica I shape and protrudes into the openings 14 and 12 in thefrontofthetankl andthe drum 2.

In the bottom of the tank 1 is an outlet 21 through which the dirtywashing liquorandrinsingwateris removed from the tank by a pump22.Thewaterex- pelled from the laundry during the spinning operation is also pumped from thetankthroughtheoutlet 21. A pipe 23 leads away from this outletand hasa branch 24which is connected to the inlet of the pump 22. A drainage pipe 25 is connected to the outlet of the pump.

Following the spinning operation the laundry is tumble-dried in the drum 2 by passing a stream of hot air over the laundry while the drum is rotated at low speed in alternate directions. The stream of hot air is produced by a high-speed fan 26 and an electric heater 27. Hotairfromtheheaterflowsintothedrum 2through a duct 28 which passes overthetop ofthe tank1 and down thefrontofthetankto discharge into the interior of the drum 2 through an aperture 29 in the wall ofthe bellows seal 17,thespace 19 be- tween the seal 1 7 and the protruding portion 20 of the door 18, and the openings 14 and 12 in thefrontwalls of the tank and the drum.The hot air passes overthe laundry in the drum 2 to extract moisture therefrom and thenflowsthrough the perforations 10 in the cylindrical wall 11 ofthedrum intothespacebe- tween this wall and the surrounding wall ofthetank 1. The moist air leaves this space via the outlet 21 in the bottom ofthetankandthe pipe 23, which serves as a duct for conducting the moist airto a condenser 30. Alternatively, the pipe 23 can be arranged to dis chargethemoistairtoatmosphereexternallyofthe machine, preferably through a lintfilterand if desired through an extensible hose.

The condenser 30 comprises a container31 which is divided internally into upper and lower chambers 32 and 33 respectively by a horizontal partition 34 which ends some distance from one wall of the containerto leave an opening 35 through which the chambers communicate with one another. The pipe 23 opens into the lowerchamber33through the op- positewall of the container31 so that the moist air flowing from the pipe 23 is constrained to flow over the surface of a quantity of cooling water 36 in the bottom of the container 31. The water vapour in the air is condensed by this cooling water and precipita tedfromtheairstream,which,thenflowsthrough the opening 35 intothe upperchamber32 ofthecontainer, whence it is conducted by a duct 37 to the inlet ofthefan 26. The container 31 has a large volume in orderto reduce the velocity of the air flow overthe cooling water 36. This water isfed into the container during the drying operation through a valvecontrolled inlet pipe 38 and leaves the container through an outlet pipe 39. One end of this pipe projects up into the lower chamber 33 through the bottom of the container; the other end is connected to the branch pipe 24 which connects the pipe 23to the pump 22. The depth ofthe cooling water in the chamber 33 is determined by the heightto which the end ofthe pipe 39 projects into the chamber.The container should, of course, be mounted well above the level to which the tank 1 is filled with waterforthe washing operation in order to avoid flooding the con- tainer.

The condenser may have the construction described in the specification of the Applicants' co-pending United Kingdom Patent Application No (Applicants' reference: PHB 33214).

The washing and drying machine shown in Figures 3 and 4 is similar in construction and operation to the machine shown diagrammatically in Figures 1 and 2 and described above, and corresponding parts ofthe machines bear the same reference numerals. Figures 3 and 4 show the whole ofthe cabinet of the machine with the exception of the back panel, which has been removed sothatthetank 1 and the drive 8,9from the motor 7 to the shaft 4 of the drum can be seen. Fig ures 3 and 4 also show schematically a box 40 in which thefan 26 and heater27 are housed and which is attached by screws or bolts (notshown) to the rear of the cabinet.The rearwall of the box 40 in Figure 3 and a side wall in Figure 4 have been broken awayto show the parts which are housed in the box. In addition to the fan and the heater these parts include a valve 41 for controlling the water feed to the con denser 30 through the pi pe 38 and a n electric motor 42 for driving the fan, the drive being transmitted through a belt 43 and pulleys 44 and 45 on the shaft of the fan impeller and the motor shaft respectively. The condenser 30 is mounted on the backofthe machine directly beneath the box 40, the water pipe 38 and air duct 37 extending through holes in the bottom of the box. The cabinet has a specially shaped back panel to cover the condenser, which panel is represented by dot-dash lines 46 in Figure 4.

The fan 26 is driven at very high speed,forex ample, 7,000 r.p.m., in order to deliver air at high pressure and velocity. This allows a small fan and a heaterwith a small heater chamber to be used so that the dimensions of the box 40 can be kept to a min imum. When the box is fitted on the back of a standard washing machine to convert it into a washer/dryer, the overall depth of the machine can still be kept within the European standard of 60 cm.

The air pressure atthefan outlet may be within the range 4 cm to 8 cm of water. With a high air pressure the air ducts may have a small cross-sectional area.

This is of particular benefit in the case ofthe hot-air duct 28 (Figures 1 and 2) which extends from the heater27 acrossthetop ofthetank 1, since the interiorof a washing machine tends to be particularly congested in this region.The corresponding region ofthe interior of the washing and drying machine of Figurges 3 and 4 is shown in Figures Sand 6, from which it can be seen that the space abovethetank 1 is largely occupied byavibration-damping mass47,forexample, a concrete block, which is secured to the tank, and a detergent drawer 48 which dispenses detergent etc. forthe washing operation.Agoodclear- ance is needed between the detergent drawer and the top of the tank 1 to allowforthe amplitude ofvibration of the resiliently suspended tank when the speed ofthe drum passes through the resonantfrequency atthe beginning ofthe spinning operation, and this clearance is utilised to accommodate the portion 49 of the hot-air duct 28 which extends across the top of the tank 1.This portion and the portion 50 which extends down the front ofthe tank have a flattened shape with an elongate cross-section, the two flat majorwalls of the portion 49 being stiffened in the lateral direction by ribs 51. The duct has a corrugated neck portion 52 of circular cross-section which is connected to an outlet duct 53 from the heater 27, the inlet of which is connected to the outlet of the fan 26 at 54. Between the neck portion 52 and the portion 49 the duct 28 has a portion 55 in which the cross-section oftheductgraduallychangesfroma circularto an elongate shape. At its discharge end the duct 28 is connected to the aperture 29 in the wall of the bellows seal 17 which extends between thefront end wall 15 ofthetank 1 and thefrontwall 3 of the cabinet.As shown in Figures 6 and 7, this aperture is of elongate shape to match the cross-section of the portion 50 ofthe duct 28 and extends in thecircum- ferential direction ofthe seal 17. The aperture 29 is surrounded by an upstanding wall 56 which projects from the outer side ofthe seal 17 and over which fits the end of the duct portion 50. The wall 56 is supported internally by a rigid sleeve 57 which is made of a plastics material and which has an elongate crosssection corresponding to the shape of the aperture 29. The sleeve 57 is formed with outwardly directed flanges58which engageovertheedgesofthewall 5Sto secure the sleeve in the aperture 29, and a stif- fening web 59 is formed across the middle ofthe sleeve.The sleeve 57 also forms a discharge nozzle for the duct 28, for which purpose the sleeve has a wall portion 60 which projects from the inner side of the seal 17 and curves round in a rearward direction to form a rearwardly facing discharge aperture 61 which directs the hotairstreamfromtheduct28tow- ardsthe central opening 12 (Figure 1) in the front wall ofthe drum 2. Due to this and to the high velocity of the air stream, very little hot air escapes into the gap between thefrontwalls of the tank and the drum and by-passes the interior of the drum. To prevent small items of laundry entering this gap, an annular rim (not shown) is provided on the seal 17.

The duct 28 is made of a heat-resistant elastomeric material, for example, silicone rubber, which allows itto be routed through the narrow space between the detergentdispenser48andthetankl.Shockscaused by contact between the duct and thetank asthe latter vibrates during acceleration of the drum to its spin speed are absorbed by deformation oftheflexible walls of the duct. The elastomeric material and flattened shape ofthe duct 28 allowthe duct to expand underthe pressure ofthe air when the fan comes into operation and to collapse when the fan stops.

The above duct construction forms the subject of the Applicants' co-pending United Kingdom Patent Application No (Applicants' reference: PHB 33215).

Although they are not shown in the drawings, thermostats are provided to control the drying temperatures, and the drying cycle is controlled by an adjustable timer (not shown).

Claims (4)

1. A machineforwashing and drying domestic laundry, comprising a cabinet containing a statio narytankfor holding washing liquor, a perforated drumwithinthetankforholding laundryto be washed and subsequently dried in the drum, the drum being rotatableinsidethetankabouta horizontal axis, a fan and a heaterfor generating a stream of hot airfor drying the laundry, and ducts for conducting the hot airfrom the heater into the drum and for conducting awayfromthetanktheairwhich passes from the drum into the space between the drum and thetankvia the perforations in the drum, characterised in that the fan is a high-speed fan and in thatthefan, a motorfordriving thefan, and the heater are all housed in a box which is mounted on the outside of the backofthe cabinet.

2. Awashing and drying machine as claimed in Claim 1 and comprising a condenser for removing moisture from the air conducted away from the tank, a pipe being providedforfeeding cooling waterto the condenser, and ducts being provided for conducting the airfrom the tankto the condenser and from the condenserto the inlet of the fan, characterised inthatavalveforcontrollingthewaterfeed to the condenserthrough said pipe is housed in said box.

3. A washing and drying machine as claimed in Claim 2, characterised in that the condenser is mounted beneath said box, the feed pipe for the cooling water and the duct for conducting the air from the condenser to the fan passing through the bottom of the box.

4. A machineforwashing and drying domestic laundry, substantially as herein described with reference to the accompanying drawings.