GB2214624A - Tumble drier with condensate monitor - Google Patents

Description

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Z_ Z 14. 6 4 1/7547/ Tumble Driers This invention relates to tumble driers.

It is known to provide heat exchangers through which the air flow passes in a re-circulating path through the drum. It is also known to provide a container for water condensed out of the re-circulating path.

The.invention provides a tumble drier which comprises a rotat,'able drum, a heat exchanger through which air flow passes in a re-circulating path through the drum in use, a container for receiving water condensed out of the recirculating air, a pad underneath the container which is resiliently urged upwards against the container, and a switch linked to the upper surface.of the container which is-arranged to operate when the weight of water in the container. is -sufficient to depress. the pad by a predetermined amount.

The use of a switch linked to the upper surface. of the-container in conjunction with a resiliently biased pad.underneath provides the simple arrangement for ensuring --that, the- container does.-not-.become. 6verfilled. The -switch-may be aoupled-to an indicatqr, such. as a warning buzzer or light, or may automatically switch the drier off.

The container can then be removed from the machine and emptied. A switch lying clear of the path of the container may be provided in conjunction with a pivotable lever linking the upper surface of the container with the switch.

A tumble drier constructed in accordance with the invention will now be described by way of example with reference to the accompanying drawings, in which:- Fig. 1 is a.8chematic-perspective view of-the tumble drier; Fig. 2 is a top plan view of the tumble drier, but with components down to and including the' drum not shown; -Fig. 3 -is a side view of the tumble drier; Fig. 4 is a front view of the tumble drier;'- is Fig. 'S is -an, enlatged -view'-of a fan-a-nd bdusing.'fo"r -re-circulating air flow; and Fig. 6 is a schematic perspec-tive''view...,of the condensate coPtainer.

The tumble drier comprises a rotatable drum 1 housed in a cabinet 2, the drum being mounted on a bearing 3 at the front.of the machiiie and a'becring'.(not shown) at th,e rear. of the machine. A load is inserted into. the tub thro ugh a door 4. The drum 1 is rotated by a.motor 5 by-a drive belt-6. The load is dried by means of an air flow 2. 5 heated by a heating element (not shown) in duct 7, which air flow circulates through the drum and through a condenser in the form of a heat 'exchanger indicated generally by the reference numeral 8 in a closed loop (see If' c - 3' 7 1 arrows 9 to 12).. The heat exchanger.is cooled by.a flow of atmospheric air (arrows-13, 14). Condensed moisture is collected in container 15.

The layout of the motor and the fans for producing the air flows will now be described. The motor 5 has output shafts at each end. As well as driving the drum belt 6, the forward shaft 16 drives a fan 17 in a housing 18 in order to impel air through the drum. -The rear shaft 19 drives- a fan 20 in a housing 21 in -order to, impel 10- atmosph'eric cooling air through the heat exchanger. The co-axially arranged motor and fans lie laterally with respect to the heat exchanger 8 Refei7ring to figure rotatable.fan wheel i.e. which is periphery that, the gradually tangential the centre 5,- the fan 17 consists ofa wheel bearing curved blades-22 in'a volute h6using i.e. the outer---of the housing is in the shape of a scroll so clearance -between the fan and the- housing increases towards to the fan wheel. of the fan wheel the. outle.t 23, which is The inlet is axially into Such a fan has a high efficiency, i,e-., a high air throughput, when the---fan is :otated in dir.i5.ction of th.e arrow, but. a low.

throughput when the 'fan is rotated in the opposite direction. The fan 20.-and its housing are identical to the fan 17 and its housing.

The heat exchanger 8 consists of a number of flat tubes 24 (through which the re-circulating air passes) which run longitudinally along the heat exchanger. At the - 4. - frotit-and-rear.ends the tub(s are set intp plas.tics panels 25, 26, which block the spaces between the tubes, and top and bottom panel 27, 28 have offset slots in them (the top one being shown at 38) for feeding the cooling air across the condenser tubes.

The heat exchanger 38 is housed in a chamber 30, with which the housing 18 communicates for the inlet to the heat exchanger-(arrow 9). The recirculating air flow is driven by the fan 17 through the tubes 24 and leaves the rear end 31 of the chamber (arrow-10), and enters the duct 7 which contains the heating element. The-now heated. re circulating air enters the rear.of the drum through a slot 32 and, after flowl:ng through the-drum, passes along a tapering duct 33 (arrow 12).and enters the fan housing 17 The heated and moist;air The fropt-panel 35, p.qnel -on the front -of the cabinet 2 may be opened) in order to. - enable the heat exchanger 8 tobe withdrawn longitudinally from the cabinet 14.. -Particles Of fib. re and of- lint filters (not shQwn) will.-.be entraine( in the.,. r.e- -circulating air f low, --and the--. heat, e_xchang(r shoud -be per.iodically removed and cleaned to" prevent it becoming clogged.

The cooling of the heat exchanger is effected by the fan 20. Cooling ambient air (arrow 13) from the atmosphere is drawn axially through inlet 35a into aperture 36 in-the fan housing 21 and enters chamber 30 axially'through an aperture 34..is driven int.o the-.cha.mb-er.,30- again. of the chamber-30 cah be opened -(and a similar 1 i 1 11 f t7 - 5. through slot.37 in the underside of the chamber. The air passes over the heat exchanger tubes 24 and leaves the chamber through slot 38 (arrow 14), which is offset relative to the slot 37 in order to cause turbulence in the cooling air flow and therefore promote better heat transfer. The air which has now been heated re-enters the atmosphere.

The side-by-side arrangement of the heat exchanger 8 on the one hand and the' motor 5 and co-axial fans 17 and 20 on the other hand permits: the use of a single motor for the drum and two fans; an axial air entry into both fan housings; and accessibility of the heat exchanger from the front of the machine..

An.-electronic circuit is provided for periodically re.versing the dir.ection-of iotation-.bf.the motor. Instead.

of providing equal periods of forward and-reyerse rotation as hi-Eherto, the motor rotates the drums and fan in a repetitive cycle consisting of a.-forward rotation of-five minutes and a reverse rotation of half.a minute. In this way, the fans are operating in an efficient manner for around 90% of--th.t&- time and i n c- 'nl -yn inefficient manner:0 for.around 10%-.of the time. Oy.era1L.the air flow through the drum is effective for drying even though.the air.flow is subject to the impedance created by the condenser and the ducting of the re-circulating loop. Equally, the short reversal is effective for preventing tangling of the clothes, in the same way as equal length reversals were hitherto.

i . -. 6 - The use of unequal.forward and reverse times permits the use of high efficiency fans but without the need for individual drive motors.

Referring to figure 3, the moisture from the recirculating air leaving the drum condenses and runs from drains 39, 40 to the pump 40a (figure 1) which is powered by its own electric motor, and which pumps the liquid to a container 15. Referring-to figure 6, the container is withdrawn 'by 'the user perio6i'cally tb- empty.1t - -and has means to prevent it being'over filled.

Thus, container 15, when fully inserted, rests on spring-loaded pressure pad 42. An operating. le'ver 43 pivoted at 44 passes through a'slot 45-'. in support panel 46. One end rests on the upper surface of-the -c ontainer 15. The other end r'esEs_ on a f urther'!ever 47 which, -when depressed, operates a -switch. 48.whiQh switches off the pump motor and the main motor. as well When the container 41 becomes filled to predetermined level, a the weight is puch that the pressure pad 42 is depressed by a predetermined amount. In turn, the end-of the Iever resting on.the-do.nt. ainer is-depressed ---andthe other.-end raised, sd tat the switch 48:operates.. The user then withdraws the container and emptie.s it, and the switch remains in.the off position. Only When the empty container has been re-inserted will the levers set the switch to the position in which the machine can restart.

Various modifications may of course be made to the J j i j 1 Ar 7. embodiment described without departing from the scope of the invention. Thus, although the motor 5 is a two pole capacitor start and run induction motor, instead it could be a relay start motor, or indeed a four pole motor could be used. Equally, different forward and reverse periods in the reversing cycle of the motor are possible: thus the ratio of forward to reverse for each cylinder could be from 5:1 to 20:1, and the cycle time could be between minutes and ten minutes. Also, the points' of entry exit from the heat exchanger could be changed. if the heat ex.changes could be water cooled instead cooled.

three to and desired of air 8 -

Claims (7)

1. A tumble drier which comprises a rotatable drum, a heat exchanger through which air flow passes in a re circulating path through the drum in use, a container for receiving water condensed out of the re-circulating air, a pad underneath the container which is resiliently urged upwards against the container, and a switch linked to the upper- surface of the container which is arranged to operate- when the- weight of water in the conta. in - er. is sufficient to depress the pad by a predetermined amount.

2. A tumble^drier as claimed in claim 1,- in which the container is removable from the tumble drier to allow it to beemptied.

3._ A -tumble drier as claimed in claim 2, in which the container is removable longitudinally through the front of the drier.---

4. A tumble drier as claimed in-claim 2 or claim 3; in which the'switch lie s clear of -the path of the container, and a pivotable lever links the upper surface of the container and the switch.

- 5-. ---Atumble drier- as claimed- in claim A, lever.oper-.ates-a.-sw. itph-via a further lever.

6. A tumble drier as claimed in any one of claims 1 to 5, in which the switch is arranged to switch the tumble drier off when the pad has been depressed by the predetermined amount.

7. A tumble drier substantially as herein described with reference to the accompanying drawings.

in which- the -ousnea IE159 at The Patent Office, State House, 66.71 High Holborn. London WClR 4TP. Further coplesmaybe obtainedfrom The Patent Office. Bales Branch, St Mary Cray, Orpington, Rent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent, Con. 1/87 I 1