GB2181221A - Machine for washing and drying domestic laundry - Google Patents

Abstract

In a machine for washing and drying domestic laundry a condenser (26) for removing moisture from the air used in the drying operation consists of a vessel (27) which has the form of a U lying on its side and which comprises upper and lower elongate chambers (28 and 29) communicating with one another at one end. Adjacent its other end the lower chamber has an inlet (31) for the moist air. During the drying operation, cold water is fed continuously into the lower chamber (29) though a valve-controlled feed pipe (35). Water leaves the lower chamber through an outlet (36) in the bottom of the chamber and a pipe (37) which projects upwardly into the chamber for a short distance to form a wall (38) around the outlet, which wall acts as a weir to determine a constant level of cooling water (39) in the lower chamber. The moist air flows over this water so that the water vapour in the air is condensed and precipitated from the air stream. The air then flows into the upper chamber (28), where drops of water picked by the air flow over the cooling water are deposited on the walls of this chamber to run back into the lower chamber. The air finally leaves the condenser through an outlet (32) in the top of the upper chamber for recirculation in the machine. <IMAGE>

Description

SPECIFICATION Machine for washing and drying domestic laundry This invention relates to a machineforwashing and drying domestic laundry, which comprises a condenserfor removing moisture from the air used in the drying operation so that this air can be recirculated in the machine, the moist air being passed over cooling water in the condenser to effect the condensation.

It is an object of the invention to provide a con denser of very simple and inexpensive construction which is particularly suitable for a washing and dry ingmachinewhichusesa high-speed fan for creating theflow of air required for the drying operation. In washing and drying machines, often referred to as "washer/dryers", the duct through which the moist air is brought to the condenser is commonly employed to carry away the condensate and the used cooling water. In a washer/dryer which has a high-speed fan the air duct cannot be used satisfactorilyforthis purpose since, dueto its high velocity, the airflow in the duct will tend to impede the flow of the water down the duct and even to drag water back into the condenser.

According to the invention there is provided a machine for washing and drying domestic laundry, which comprises a condenserfor removing moisture from the air used in the drying operation so that this air can be recirculated in the machine, the moist air being passed over cooling water in the condenser to effectthe condensation, characterised in that the condenser comprises upper and lower elongate chambers extending substantially horizontally one above the other and communicating with one another at one end, the lower chamber having at or adjacent its other end an inletforthemoistairand the upper chamber having an outletthrough which air can leave the condenser, and the condenser further having an inletthrough which cooling water can be fed to the lower chamber and an outlet in the bottom of the lowerchamberthrough which cooling water and condensate can leave this chamber, the latter outlet being surrounded by a wall which projects upwardlyfrom the bottom of the lower chamber and which acts as a weirto determine a constant level of cooling water in the lowerchamber.

A preferred embodiment of the invention is characterised in that the condenser comprises a vessel having the form of a U lying on its side with one limb directly above the other, the upper limb constituting the upper chamber of the condenser and the lower limb constituting the lower chamber and the connection between the limbs constituting a passage through which the chambers communicate with one another at said one end.

With this simple construction the condenser can be manufactured cheaply as a plastics moulding, preferably a blow moulding, to minimise the number of joints and keep the tool cost low. A simple stiffen- ing ofthe moulding can be obtained by forming a rigid web between two parts of the moulding which form the upper and lower chambers of the condenser vessel.

Asimplemeansofformingthewallaroundthe outlet in the bottom of the lower chamber is provided in an embodiment of the invention which is characterised in that a pipe is connected to the outlet in the bottom ofthe lowerchamberto conduct cooling waterand condensate awayfrom this chamber, and an end portion ofsaid pipe projects upwardly into the lower chamberto form said wall.

An embodiment ofthe 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 embodying the invention, the cabinet of the machine, with the exception of the front wall, being omitted for the sake of clarity, Figure2 is a diagrammatic rear elevation of the machineshown in Figure 1,withthewholeofthe cabinet omitted, Figure3 is a side elevation of a washing and drying machine which is similar in construction and operation to the machine shown in Figures 1 and 2 and in which the condenser is mounted on the back ofthe cabinetofthe machine beneath a box containing a fan and heater, and Figures 4 5and 6are side, plan and end views respectively, drawn to a very much larger scale, of the condenser vessel of the machines shown in Figures 1 and 2 and in Figure 3.

The washing and drying machine shown diagrammatically in Figures 1 and 2 comprises 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.Thetank 1 is suspended in a cabinet, of which the front wall is shown at 3 in Figure 1. The tank is arranged with its axis disposed horizontally, and the drum is rotatably supported inthetankcoaxially therewith by a shaft 4 which projects from the rear end wall 5 ofthe drum and isjournalled in a bearing (not shown) in the rear end wall 6 ofthetank.Outside the tankthe shaft 4 receives drive from an electric motor (not shown) by which the drum 2 can be rotated at low speed in alternate directions during the washing and tumble-drying operations and at high speed in one direction only during the spinning operation.

The drum 2 has perforations 7 (Figure 1) in its cylindrical wall 8 and a large circular central opening 9 in its front end wall 10 through which the laundry can be loaded into the drum. Thetank 1 has a similaropening 11 in its front end wall 12 and a corresponding opening is provided inthefrontwall 3 of the cabinet, the three openings being coaxial with one another. A flexible annularseal 13,forexample, a rubber bellows seal, is fixed to the front end wall 12 ofthe tank 1 around the opening 11 therein and to the front wall 3 of the cabinet around the corresponding open inginthiswall. Forclosingthisopeningahingedpor- thole door 14 is provided on the front wall ofthe cabinet, the door being arranged to seat in a water- and air-tight manneron a rim oftheseal 13 atthefront edge ofthe seal, and the construction ofthis seal and the door 14 being such asto leave an annular space 15 between the seal 13 and a transparent portion 16 of the door which has a frusto-conical shape and protrudes into the openings 11 and 9 in thefrontofthe tank 1 and the drum 2.

In the bottom ofthetank 1 is an outlet 17 through which the dirty washing liquor and rinsing water is removedfromthetankbya pump 18.Thewaterexpelled from the laundry during the spinning operation is also pumped from thetankthrough the outlet 17. A pipe 19 leads away from this outlet and has a branch 20 which is connected to the inlet ofthe pump 18. A drainage pipe 21 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 hotairoverthelaundrywhilethedrum is rotated at low speed in alternate directions. The stream of hot air is produced by a high-speed fan 22 and an electric heater 23. Hot air from the heater flows into the drum 2 through a duct 24which passes over the top of the tank 1 and downthefrontofthetankto discharge into the interior of the drum 2 through an aperture 25 in the wall of the bellows seal 13, the space 15 between the seal 13 and the protruding portion 16 ofthe door 14, and the openings 11 and 9 in thefrontwalls ofthetankand the drum.The hotair passes overthe laundry in the drum 2to extract moisturetherefrom and then flows through the perforations 7 in the cylindrical wall 8 ofthe drum into the space between this wall and the surrounding wall ofthe tank 1. The moist air leaves this space via the outlet 17 in the bottom of the tank and the pipe 19, which serves as a ductfor conducting the moist airto a condenser 26.

The condenser 26 comprises a vessel 27 having the form of a U lying on its side with one limb directly above the other. The upper limb constitutes an elongate upper chamber 28 ofthevessel and the lower limb an elongate lower chamber 29, the two chambers extending substantially horizontally. The connection between the two limbs constitutes a passage 30through which the chambers communicate with one another at one end. Adjacent its other end, in one side, the Iowerchamber29 has an inlet31 forthe moist air, to which inletthe pipe 19 is connected. In the top of the upper chamber 28, nearthe end thereof which is remote from the passage 30, is an outlet 32 through which air can leave the vessel 27. This outlet is connected to the inlet duct 33 of the fan 22.Also in the top of the upper chamber 28, directly above the passage 30, is an inlet 34for cooling water, to which inlet a valve-controlled feed pipe 35 is connected.

During the tumble-drying operation, cold water from the household supply is fed continuously to the lower chamber 29 via the pipe 35, which extends down through the passage 30 to a point just above the bottom ofthe lower chamber. Water leaves this chamberthrough an outlet36 in the bottom ofthe chamber and a pipe 37 which is connected at one end to the outlet36 and atthe other end to the branch pipe 20 which connects the pipe 19 to the pump 18.

As indicated in dot-dash lines in Figure 4, the upper end ofthe pipe 37 extends into the lowerchamber29 for a short distance to form a wall 38 projecting upwardly from the bottom of the chamber 29 around the outlet 36. As shown in Figure 2, this wall acts as a weirto determine a constant level of cooling water 39 in the lower chamber. The moist air conducted into the chamber 29 by the pipe 19 flows overthesurface ofthiswater, and the water vapour in the air is condensed thereby and precipitated from the air stream.

The airflow over the water outlet 36 tends to pick up a part of the water, creating droplets above the outlet and so assisting the action of the condenser. From the lower chamber 29 the airflows through the pas- sage 30 intotheupperchamber28andthence throughtheoutlet32intotheinletduct33ofthefan 22 for recirculation in the machine. In the upper chamber 28, drops of water picked up by the airflow overthe cooling water in the lowerchamberaredep- osited on the walls of the upper chamber before the air accelerates into the fan inlet duct 33.These drops of water run down to the bottom of the upper chamber and thence back into the lowerchamber, the bottom wall ofthe upperchambersloping downwardly from the side walls to facilitate this, as can be seen in Figure 6.

The chambers 28 and 29 have a substantially larger cross-sectional area than the pipe 19 in orderto re ducethevelocityofthemoistairenteringthecon- denser and flowing over the cooling water 39. The high velocity ofthe airflow in the machine during the drying operation is due to the use of a high-speed fan, for example, a fan driven at 7,000 r.p.m., which has the advantage that owing to the high pressure and high velocity ofthe air delivered by the fan,the heater 23 may have a small heater chamber and the air ducts 24 and 19 a small cross-sectional area. This yields significant benefits in terms of the space required to accommodate these items.

Figure 3 shows the condenser26 mounted on the backofthecabinetofawashing and drying machine, directly beneath a box 40 containing the fan 22 and heater 23, in an arrangementsimilartothatdescri- bed in the specification of the Applicants' co-pending United Kingdom Patent Application No (Applicants' reference: PHB 33213). The water in let 34 a nd air outlet 32 of the condenser extend into the box 40 forconnectiontothewaterfeed pipe 35 and the fan inlet duct 33 respectively. A valve (not shown) for controlling thewaterfeed through the pipe 35 isalso housed in the box 40. The condenser must, of course, be mounted well above the level to which the tank 1 is filled with waterforthewashing operation in orderto avoid flooding the condenser.

The condenser vessel 27 can be manufactured cheaply as a plastics moulding, preferably a blow moulding in,forexample,polypropylene,soasto have the minimum number of joints and to keep the tool cost low. To stiffen the moulding a rigid web 41 is formed between the two parts which constitute the upperand lowerchambersofthecondenservessel.

Claims (5)

1. A machineforwashing and drying domestic laundry, which comprises a condenser for removing moisturefrom the air used inthedrying operation so that this air can be recirculated in the machine, the moist air being passed over cooling water in the con denser to effect the condensation, characterised in that the condenser comprises upper and lower el- ongate chambers extending substantially horizontally one above the other and communicating with one another at one end, the lower chamber having at or adjacent its other end an inletforthe moist airand the upper chamber having an outlet through which aircan leavethe condenser, and the condenser further having an inlet through which cooling water can be fed to the lower chamber and an outlet in the bottom ofthe lower chamber through which cooling water and condensate can leave this chamber, the latter outlet being surrounded by a wall which pro jects upwardly from the bottom of the lower chamber and which acts as a weirto determine a constant level of cooling water in the lower chamber.

2. Awashing and drying machine as claimed in Claim 1, characterised inthatthecondensercom- prises a vessel having the form of a U lying on its side with one limb directly above the other, the upper limb constituting the upper chamber of the condenser and the lower limb constituting the lower chamberandtheconnection between the limbs constituting a passage through which the chambers communicate with one another at said one end.

3. Awashing and drying machine as claimed in Claim 2, characterised in thatthevessel ismanufactured as a plastics moulding with a stiffening web between two parts of the moulding which form the upper and lower chambers of the vessel.

4. Awashing and drying machine as claimed in Claim 1,2 or 3, characterised in that a pipe is connected to the outlet in the bottom ofthe lower chamber toconductcoolingwaterand condensateawayfrom this chamber, and an end portion of said pipe projects upwardly into the lower chamberto form said wall.

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