GB2082741A

GB2082741A - Laundry Drier

Info

Publication number: GB2082741A
Application number: GB8118735A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-07-23
Filing date: 1981-06-18
Publication date: 1982-03-10
Also published as: FR2487392A1; GB2082741B; DE3027900A1; ES8204782A1; IT1137741B; DE3027900C2; ES503275A0; IT8123021A0

Abstract

A household laundry drier is provided with an air-cooled device (2) for condensing moisture expelled from the washed articles, which moisture is carried in a circulating air stream flowing in a closed circuit. The device comprises a plurality of plates (21) with good thermal conductivity disposed in the direction of the circulating air in a tunnel-shaped housing (24), the housing being provided in its side walls with apertures (25) registering with the plate profiles. The apertures are in communication with cooling air cavities of the associated plate (21) extending approximately transversely to the circulating air stream and are connected, outside the housing (24), to ducts for guiding the cooling air. <IMAGE>

Description

SPECIFICATION Laundry Drier The present invention relates to a household laundry drier and has particular reference to a drier provided with means for condensing moisture which has been expelled from washed articles and is entrained in a circulating air stream.

Known laundry driers of this kind merit improvement in respect of the heat transfer between the circulating air and cooling air and in respect of the constructional complication of the condensing means.

According to the present invention there is provided a household laundry drier provided with a condensor for condensing moisture entrained in an air stream circulating in a closed circuit in the drier, the condenser comprising a housing defining a duct for such air stream, a plurality of thermally conductive plate elements arranged in the housing duct in the path of the air stream and each provided with a plurality of internal cooling air passages extending substantially transversely to the direction of flow of the air stream through the duct, the housing being provided in wall means thereof with cooling air inlet means and outlet means communicating with the passages, and cooling air inlet duct means and outlet duct means communicating with the inlet and and the outlet means respectively for conducting cooling air to and from the passages.

Expediently, the elements comprise plates which have good thermal conductivity and which are disposed in the direction of the circulating air in a tunnel-shaped housing which possesses, in its side walls, apertures registering with the plate profiles, the apertures being in communication with cavities of the associated plate that extend approximately transversely to the circulating air stream and being connected outside the housing to the duct means.

This form of construction makes possible an intensive indirect contact between the circulating air and the cooling air for the transfer of thermal energy. It also offers optimum conditions for reduced constructional complication.

Preferably, the plates are movably mounted in guide rails on the side walls of the housing. Such an arrangement has the advantage that the plates can be pulled out of the condensor without the assistance of a tool and can be easily cleaned.

Moreover, the internal space of the housing can also be easily cleaned in this manner.

Preferably, at least one of the plates is installed inclined transversely to the circulating air stream, whereby water condensing from the circulating air on the upper surface of the or each inclined plate accumulates at one side of each plate and is driven by the circulating air stream towards an outlet and of the housing. The water can collect there and be drained off. However, at least one of the plates can be installed inclined in the direction of the circulating air stream, which promotes conveying of the condensed water caused by the circulating air stream. This feature can also be combined with the previously described feature.

In order that the condensate collected at the outlet end of the housing is not arbitrarily swept away and distributed by the circulating air stream, the plates may each possess a condensate collecting channel at the outlet side for the circulating air.

These collecting channels may with advantage possess discharge spouts which are disposed one above another and feed into a condensate collecting vessel. In this manner, controlled removal of the condensate is ensured.

An especially simple manufacture of such a plate is possible if the plate is composed of two sheet portions extending parallel to each other and enclosing therebetween a ribbed sheet portion, folded in zig-zag form, surrounding the cavities.

If the ribbed sheet portion, folded in zig-zag form, has a meandering shape, manufacture is still simple and heat transfer from the cavities to the parallel sheet portions of the plates can be optimized by the transverse webs of the meandering form.

Preferably, each plate is made from a single strip of sheet material. The simplicity of manufacture will be apparent, as the plates can be readily produced on automatic machines.

If the folded, ribbed sheet portion is disposed in the centre of the strip between the two parallel sheet portions, then one end of the upper sheet portion can be formed as a collecting channel.

The lower sheet portion can then simply be flat.

In another embodiment, the folded ribbed sheet portion is disposed at one end of the strip, This arrangement also simplifies the manufacturing procedure in that first of all the ribbed sheet portion of the strip is folded inwards and then the outer, flat portion of the strip is laid over the ribbed sheet portion through the same spatial section. In this case the condensate collecting channel may be provided both at one side (free end of the flat sheet) and also at the other end (joining fold between the two flat sheet portions).

In all cases a non-detachable connection between the contact points of the flat sheet portions with the ribbed sheet portion is desirable.

An appropriate welding procedure or gluing procedure can be used for this purpose.

Connected together in this manner, the plates are extremely stiff and thereby easy to handle.

Embodiments of the present invention will now be more particularly described by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a schematic cross-section of a household laundry drier provided with an aircooled condenser in accordance with an embodiment of the invention, Fig. 2 is a perspective view, to an enlarged scale, of the condenser, Fig. 3 is a cross-sectional view of plates in such a condenser in accordance with a first embodiment, Fig. 4 is a cross-sectional view of plates in such a condenser in accordance with a second embodiment, and Fig. 5 is a detail, in cross-section, of a housing of the condenser showing the mounting of one such plate in the housing.

Referring now to the drawings, there is shown in Fig. 1 a laundry drier comprising a housing 10 with an internal drying chamber 11. Between this chamber and the rear wall of the drier there is an air feed duct 12 in which air is heated up by means of a heating device 13 and blown by a blower 14 through a grating wall 15 into the drying chamber. At the front side of the laundry drier there is a feed opening 1 6 for loading of articles to be dried. The opening 16 is then closed by a door 17.

The air blown by the blower 14 through the drying chamber 11 subsequently passes through an annular gap between the door and the outer frame of the opening 16 and then into the discharge air duct 19 via a slub sieve 18. From there the air passes into an air-cooled device in the form of a condenser 2. The condenser 2 is illustrated partly cut away and contains plates 21 of good thermal conductivity including cavities, which are traversed transversely to the circulating air by fresh air. The circulating air is represented at the warm (inlet) side by a solid arrow and at the cold (outlet) side by a longitudinally striped arrow (broken lines in Fig. 1). The warm, moisture-laden circulating air gives up heat and moisture to the surfaces of the plates 21 and flows cooled to the blower 14 thus completing a closed circuit.The moisture accumulates at the outlet from the condenser and flows to a condensate collecting vessel 22, from which the condensate can be pumped out or removed by hand.

At the front side of the laundry drier housing 10 there is also a door or flap 23, which can be opened by the operator for the purpose of cleaning the condenser 2. Before cleaning, the plates 21 can be pulled out of the condenser 2 and cleaned outside.

The condenser 2, illustrated diagrammatically in Fig. 2, has a tunnel-shaped housing 24 with a circulating air inlet opening (solid arrow) connected to the discharge air duct 19 and with a circulating air outlet opening (longitudinally striped arrow) connected to the blower 14. At the side walls of the housing 24 apertures 25 are provided, which receive the inflowing cooling air (white arrow) at one side (the rear in Fig. 2), allow it to pass through the cavities of the plates 21, and lead it back again to atmosphere (transversely striped arrow) at the other side (front in Fig. 2) via a connected duct (indicated in dot-and-dash line).

The plates 21 are mounted in the interior of the housing 24 in guide rails 26 so as to be slidable in the direction of the circulating air. Corresponding to the arrangement of the condenser 2 in Fig. 1, the plates 21 illustrated in Fig. 2 can therefore be pulled out towards the rear.

The circulating air sweeping through the condenser 2 conveys the condensate precipitating on the plates 21 towards the circulating air outlet opening (longitudinally striped arrow), where it drips into a condensate collecting channel 27 of the housing 24. The channel 27 conducts the condensate into the collecting vessel 25 (Fig. 1). An example of construction especially suitable for the plates 21 is illustrated in Fig. 3 in cross-section oriented in the direction of the air circulation. This plate consists of a single-piece strip of sheet material, one end 211 of which constitutes the lower face of the plate. At the fold towards the upper face 212 of the plate 21, the sheet is shaped to form a condensate collecting channel 213.Above the lower end 211 , the upper face 212 is again folded downwards and continues into the meanderingly folded ribbed sheet 214, which bears at large areas alternately against the lower face and upper face of the plate 21. The individual webs of the meander constitute, between the upper surface 212 and the lower surface 211, elongate cavities 215, which extend transversely to the circulating air stream.

Instead of the example shown in Fig. 3, the plate can, starting from the collecting channel 13, pass immediately into the meandering ribbed sheet 214 and terminate at the righthand end of the illustrated plate, folded twice upwards, in the surface 212.

In the embodiment illustrated in Fig. 4, the lower face of the plate is formed by one end portion 21 6 of a single-piece sheet strip material.

At the lefthand end of this portion, the zig-zag shaped, folded ribbed sheet 217 commences, which in turn is bent upwards at the righthand end to continue into the upper plate surface 218.

the lefthand end of which is shaped to form a condensate collecting channel 219. This plate includes cavities 251 of prismatic cross-section extending transversely to the circulating air flow, the prisms standing alternately on a side face and an apex or ridge. At the ridges, the ribbed sheet has contact alternately with the lower plate surface 216 and the upper plate surface 218, which contact is suitable for non-detachabie fixing.

The plates 21 (Fig. 3 and Fig. 4) have particularly good stiffness when their contact points are fixed and thus they can be easily handled by the user. ; The detail illustrated in Fig. 5 of the guiding of, the plates 21 in the laternal guide rails 26 of the housing 24 shows how the cavities 21 5 of the inserted plates 21 align with the apertures 25 in the side wall of the housing 24. To seal the circulating air from the fresh air (transversely striped arrow), strips 261 of sealing material are incorporated into the guide rails 26. The dot-anddash lines show the connection of the cooling air duct to the side wall of the condenser housing 24.

A condenser constructed as described above is easy to gain access to and to clean. This advantage is of great importance in the light of the fact that in household laundry driers a very large number of extremely fine slub materials, particles of dust and lime residues are entrained in the circulating air and in the course of time can foul the condenser, causing its efficiency to decrease. The individual plates of the condenser are - as already described - inexpensive to manufacture because a large number of identical parts are used. Moreover, the design of the condenser offers for the first time the possibility of adapting the heat transfer performance to the desired requirements. For this purpose, the number of plates to be used can be varied, the housing remaining unchanged. The number of the individual plates shown in the illustrated embodiments is therefore capable of change.

Claims

1. A household laundry drier provided with a condenser of condensing moisture entrained in an air stream circulating in a closed circuit in the drier, the condensor comprising a housing defining a duct for such air stream, a plurality of thermally conductive plate elements arranged in the housing duct in the path of the air stream and each provided with a plurality of internal cooling air passages extending substantially transversely to the direction of flow of the air stream through the duct, the housing being provided in wall means thereof with cooling air inlet means and outlet means communicating with the passages, and cooling air inlet duct means and outlet duct means communicating with the inlet means and the outlet means respectively for conducting cooling air to and from the passages.

2. A drier as claimed in claim 1, wherein the plate elements are movably mounted in guide rails at side walls of the housing.

3. A drier as claimed in either claim 1 or claim 2, wherein at least one of the plate elements is arranged at an inclination transversely to said direction of flow of the air stream through the housing duct.

4. A drier as claimed in any one of the preceding claims, wherein at least one of the plate elements is arranged at an inclination in said direction of flow of the air stream through the housing duct.

5. A drier as claimed in any one of the preceding claims, wherein each of the plate elements is provided with a condensate collecting gutter at an outlet end of the housing duct.

6. A drier as claimed in claim 5, wherein the gutters are provided with outlet spouts disposed one above the other, a condensate collecting vessel being arranged to receive condensate from the spouts.

7. A drier as claimed in any one of the preceding claims, wherein each of the plate elements comprises two sheet portions extending parallel to and at a spacing from each other, and a further sheet portion folded in generally zig-zag form and arranged between said two sheet portions to define the cooling air passages of that element.

8. A drier as claimed in claim 7, wherein the further sheet portion is folded so as to extend on a meandering path.

9. A drier as claimed in either claim 7 or claim 8, wherein said two sheet portions and the further sheet portion are parts of a single piece of sheet metal.

10. A drier as claimed in claim 9, wherein the further sheet portion is disposed in the single piece of sheet metal intermediate said two sheet portions.

11. A drier as claimed in claim 9, wherein the further sheet portion is disposed at one end of the single piece of sheet metal.

12. A household laundry drier substantially as hereinbefore described with reference to the accompanying drawings.