WO2008073052A1

WO2008073052A1 - Drying cabinet

Info

Publication number: WO2008073052A1
Application number: PCT/SE2007/050998
Authority: WO
Inventors: Anders SAHLÉN; Peder Bengtsson; Pia GRÅSJÖ
Original assignee: Asko Cylinda Ab
Priority date: 2006-12-15
Filing date: 2007-12-14
Publication date: 2008-06-19
Also published as: SE0602702L; SE531702C2; EP2094898A1; EP2094898A4

Abstract

Drying cabinet having a drying chamber, which is intended to accommodate objects installed for drying by means of flows of heated air in the drying chamber and is provided with air inlets (14, 28) to the drying chamber and air outlets from the drying chamber. A fan device drives the air flows through the drying chamber, which is delimited by three wall portions, consisting of two side wall portions (1, 2) and a rear wall portion (3), a bottom portion (7), a roof portion (4) and a front portion (5) having a door (6) for opening and closing of the drying chamber. The bottom portion (7) forms an outlet box, to which the outlet leads for through-flow of the outlet air.

Description

TITLE

Drying cabinet

TECHNICAL FIELD

The present invention relates to a drying cabinet according to the preamble to the following Patent Claim 1.

BACKGROUND ART

The drying cabinets for laundry and clothes which are commonly found on the market are based on a simple flow principle with a blow-down of heated air perpendicularly from the roof down into the drying chamber of the cabinet, to turn round in the bottom of the cabinet and be blown out close to the roof. This principle is simple and cost-saving, but the result is dependent on the hanging of the laundry, which can adversely affect the air flow through the drying chamber. The reversal of the air flow in the cabinet bottom also produces a risk of overdrying at the bottom, at the same time as the laundry gets less dry at the top, i.e. uneven drying is obtained. The drying method is usually based on deaerator technology, in which the air is heated to a high temperature, preferably by electrical means, and evacuated, which calls for an outlet duct from the cabinet and the premises concerned out into the environment. Alternatively, the warm and moist air can be condensed by cooling in a condenser, which in more advanced solutions possibly forms part of a heat pump system, and can also be recirculated and reheated in a closed circuit, or alternatively be blown out within the premises.

Through US 4,180,919, it is previously known to create a transversely directed air current with an inlet to and outlet from the drying chamber distributed at different heights and a duct system in two opposite walls. This produces a costly construction, which impinges on the drying chamber. There is also a risk of condensation problems, with concomitant lower drying effect and corrosion problems on the bottom of the drying chamber due to cooling against a cold surface.

DISCLOSURE OF INVENTION

The object of the present invention is to provide a drying cabinet in which a reduced risk of condensation problems on cold surfaces is achieved.

The said object is achieved by means of the drying cabinet according to the invention, the characteristics of which emerge from the following Patent Claim 1.

BRIEF DESCRIPTION OF DRAWINGS

The invention will be described in greater detail below with a couple of illustrative embodiments with reference to the appended figures, in which

Fig. 1 is a front view of the drying cabinet according to the invention, in which the door is not shown,

Figs. 2 and 3 are vertical sections through the drying cabinet along the line A-A and B-B respectively in Fig. 1 , in which the door is shown,

Fig. 4 shows a horizontal section through the drying cabinet along the line C- C in Fig. 1 , in the form of a perspective view,

Fig. 5 shows the vertical section A-A, in the form of a perspective view of the lower portion of the drying cabinet,

Fig. 6 shows the vertical section B-B, in the form of a perspective view of the lower portion of the drying cabinet, in illustration of the inlet flows, Figs. 7, 8 and 9 show the section A-A in the form of schematic views of the drying cabinet, in illustration of the outlet flows,

Figs. 10, 11 and 12 show the section B-B in the form of schematic views of the drying cabinet, whilst

Fig. 13 shows the section B-B in the form of a schematic view of the drying cabinet in an alternative embodiment having a filter on the outlet side.

MODE(S) FOR CARRYING OUT THE INVENTION

In the shown example, the drying cabinet according to the invention is primarily intended for drying laundry, wet articles of clothing, shoes, etc. in households, day nurseries, institutions, etc. and utilize condenser technology for the dehumidification. As can be seen, inter alia, from Figs. 1 -3, the drying cabinet is box-shaped and is delimited by two mutually opposite side wall portions 1 , 2, a rear wall portion 3 (hereinafter referred to as the back wall portion), a roof portion 4 and a front portion 5, which is intended to normally be closed off by a door 6, as indicated in Figs. 2 and 3. This door is conventionally pivotably hung at the front edge of one side wall portion by means of a butt hinge, for switching between the closed and the open position. A bottom portion 7 delimits the interior of the drying cabinet downwards towards a fan/condenser assembly 8 in a lower chamber 9, which expediently is outwardly shielded.

The side wall portions 1 , 2, the back wall portion 3, the roof portion 4, the door 6 in the closed position, and the bottom portion 7 delimit a box-shaped drying chamber 10, i.e. with the shape of a parallelepiped, in which the articles to be dried are placed. For this purpose, the drying cabinet 10 is provided with devices which can support the articles, for example hinged rods or cradles, grid shelves, wire baskets, or the like. Advantageously, the inner chamber can have standard measurements and its side walls 1 , 2 can be provided internally with standard fastening facilities for standard fittings for wardrobes. The articles or objects, which for the sake of simplicity shall hereinafter be referred to as the drying ware, can hence to the greatest possible extent be distributed over the volume of the drying chamber 10, but can also, in the case of lower moisture content, lie in baskets.

For air exchange and drying of drying ware in the drying chamber 10, an inlet to the chamber and an outlet from the chamber are provided, for the admission and discharge of drying air. Fig. 1 offers a view straight into the drying chamber, from which it can be seen that a plurality of inlet openings are disposed in the back wall portion 3, in the shown example 15 slit-shaped openings comprising an uppermost and a lowermost opening 14, 28. In the example, the inlet openings extend horizontally and symmetrically over the width of the back wall and occupy, for example, half of the width of the back wall. The inlet openings 14, 28 are distributed over substantially the entire height of the back wall portion 3, i.e. with the uppermost inlet opening 28 in the top of and the lowermost inlet opening 14 in the bottom of the back wall portion.

In the section according to Fig. 2, it can be seen that the inlet openings 14, 28 are realized with guide members 29, for example configured as so-called gills, which are most simply configured by form pressing of the wall plate 30 in which the openings are situated. The guide members are advantageously arranged to guide the air flow obliquely forwards and downwards into the drying chamber 10, which shall be described in greater detail below. As can also be seen from Fig. 2, in the back wall portion 3 there is disposed an inlet duct 31 , which extends along substantially the entire height of the drying chamber 10 from the lower chamber 9 below the bottom portion 7 and emerges at a plurality of locations in the drying chamber via the inlet openings 14, 28. As can be seen from Fig. 1 and from the section in Fig. 3, the outlet from the drying chamber 10 is arranged with a number of, in the example two, outlet openings 12, 13 in the top of the back wall, i.e. in substantially the same plane as the inlet openings 14, 28. The outlet openings are constituted by holes, for example individual grilled holes or hole clusters with a plurality of tiny holes, and lead directly into their respective outlet duct 32, 33, which run on one side each of the inlet duct 31 down over substantially the entire height of the drying chamber 10 down to the bottom portion 7. As can be seen from the shown example, the holes are preferably situated at the upper end of the outlet ducts 32, 33. More precisely, the outlet openings 12, 13 are therefore exclusively orientated to an upper portion of the back wall, i.e. the outlet openings are absent in the back wall below the upper portion of the back wall.

The inlet duct 31 and the outlet ducts 32, 33 are integrated in the back wall portion 3 and are formed by the back wall portion being made up of an outer, whole back wall 34, which forms the back of the drying cabinet, and an inner back wall 36, which is situated with a gap 35 to the said outer back wall and which simultaneously forms the back wall of the drying chamber and is provided with inlet openings 14, 28, on the one hand, and outlet openings 12, 13, on the other hand.

The outlet ducts 32, 33 are separated from the inlet duct 31 by means of transverse, whole partition walls 37-40, which extend over the entire height of the drying chamber 10 and bridge the gap 35. As can be seen from the horizontal section in Fig. 4, each partition wall is advantageously double- walled, with an intervening air gap, whereby reduced energy losses, caused by heat transfer from the air flow of the inlet with higher air temperature to the air flow of the outlet with lower temperature, are achieved. The combined cross-sectional area of the two outlet ducts is advantageously substantially equal in size to the area of the inlet duct. From the vertical sections in Figs. 5 and 6, it can be seen that the fan/condenser assembly 8 is connected on its pressure side to the lower end of the inlet duct 31 , in the example by a pipe coupling 41. On the suction side, the fan/condenser assembly is parallel-connected to the outlet ducts 32, 33, which therefore, at their lower end, converge into a common duct.

In the shown example, which is shown schematically in Figs. 10-12, this convergence is achieved by the configuration of the bottom portion 7 as a double bottom, i.e. double-walled with an upper bottom wall 42, which constitutes the bottom of the drying chamber 10, and a lower bottom wall 43, which partitions off the lower chamber 9. The double bottom forms, more precisely, an outlet box 44, which is closed to the sides and forwards and also against the inlet duct 31 , but is therefore open to the rear towards the lower end 45 of each of the outlet ducts 32, 33, by virtue of the fact that the outer back wall 34 extends downwards to and meets the lower bottom wall 43 of the bottom portion 7 and the inner back wall 36 reaches down to the upper bottom wall of the bottom portion, yet the inlet duct is shielded from the outlet box 44. In the lower bottom wall of the outlet box, close to the front edge 46 of the box, there is disposed an outlet opening 47, to which connects an outlet pipe 48 leading to the suction side of the fan/condenser assembly 8, see Figs. 5 and 6. Advantageously, the outlet opening 47 extends over a large part of the width of the bottom portion 7, whereby the air flow in the formed bottom duct in the outlet box is spread over the entire depth of the bottom, so that the bottom of the drying chamber 10 is kept relatively warm and condensation problems against cold surfaces are reduced.

From the condenser, a line 49 for the evacuation of condensation water leads to either a collecting vessel or directly to the central drainage system.

The drying cabinet also incorporates a heating device 50 for heating the inlet air, so that the moisture in the drying ware evaporates and can be transported away from the drying chamber 10. This heating device is placed somewhere on the inlet side, in the shown example in the form of a heating element at the lower end of the inlet duct 31. The element can be driven with direct electricity, or can constitute a coiled tube with waterborne heat, which can be electrically driven, gas-driven or driven from some other power source.

With the above-described drying cabinet according to the invention, a very good drying effect can be achieved in a large number of different load scenarios, due to the favourably distributed air flow in the drying chamber 10, illustrated with reference to the schematic views in Figs. 7-12.

Figs. 7 and 10 show the inlet and outlet flow in a case involving hanging cloths 51 , 52, 53, i.e. relatively thin objects covering a wide area, in which each shown cloth can represent a plurality of cloths which hang parallel in each "storey" on rods or cradles, for example, advantageously such that they are directed out from the back wall. The inlet air is heated in the heating element 50 and flows upwards through the inlet duct 31 in the direction of the arrow 54 and flows obliquely downwards and inwards through the inlet openings 14, 28, see the flow arrows 55. The respective opening area of the inlet nozzles can be adjusted such that an even flow and desired flow direction is obtained in each part of the cabinet. After the various air flows have passed through their flow loop, the air flows out through the outlet openings 12, 13 and onward down into the outlet ducts 32, 33, onward through the bottom duct into the outlet box 44 and out to the fan/condenser assembly 8, see the flow arrows 56, 57, 58, 59 in Fig. 10.

Figs. 8 and 11 correspondingly show another load scenario involving smaller, possibly more three-dimensional objects such as shoes 60-63, which are placed at greater or lesser intervals, so that the flow loops can sweep around the objects and subsequently flow out through the outlet openings 12 and the outlet ducts 32. Figs. 9 and 12 correspondingly show a further load scenario involving objects lying on shelves 64, 65 or baskets, so-called wire baskets, i.e. open-work object carriers through which the air can flow, so-called flat-drying, i.e. in which the drying ware is supported horizontally. Here too, the air currents are spread through the large number of air loops running in a U-shape through the drying chamber, before the air flows out through the outlet openings 12 and the outlet ducts 32.

In the alternative embodiment according to Fig. 13, the outlet box 66 is larger, more precisely taller, so that it accommodates a filter unit 67, expediently in the form of a filter cassette, which is easily removable through a front opening 68 which normally is closed. A number of different filter types can be placed in the outlet box 66 individually or in combinations. Various examples are fluff and dust filters of a type similar to that used in tumble driers, filters with active carbon for treatment of odours, electrostatic/ionizing filters for treatment of odours and for air purification, HEPA filters for air purification and UV filters/photocatalytic filters for air purification.

Through the arrangement, on the one hand, of the back wall as a double wall heated by the inlet/outlet system and, on the other hand, of the bottom portion 7 as a double bottom forming a part of the outlet system, moisture is prevented from condensing against a cold surface, which gives a high drying effect and reduces the risk of corrosion.

The invention is not limited to the examples which are described above and shown in the drawing. The inlet duct and the outlet ducts can, for example, change place, so that a centrally placed outlet duct having, for example, a single outlet opening is obtained, the outlet duct being surrounded by two inlet ducts each having rows of inlet openings. In such a case, the outlet box is connected to the central duct and is shielded from the two inlet ducts on either side. Even though the invention is largely tailored to drying cabinets using condenser technology, it is conceivable that it can be used for drying cabinets employing deaerator technology, in which the outlet air is evacuated to the external air. Instead of the shown technology, a more advanced, yet still more energy-saving condenser technology involving a heat pump system may also be used.

Claims

1. Drying cabinet having a drying chamber (10), which is intended to accommodate objects installed for drying by means of flows of heated air in the drying chamber and is provided with air inlets (14, 28) to the drying chamber and air outlets (32, 33) from the drying chamber, and a fan device for driving the air flows through the drying chamber, which is delimited by three wall portions, namely two side wall portions (1 , 2) and a rear wall portion (3), a bottom portion (7), a roof portion (4) and a front portion (5) having a door (6) for opening and closing of the drying chamber, characterized in that the bottom portion (7) forms an outlet box (44/66) to which the outlet (32, 33) leads for through-flow of the outlet air.

2. Drying cabinet according to Patent Claim 1 , characterized in that one of the wall portions (3) has, on the one hand, a plurality of inlet openings (14,

28), which are distributed over the height of the wall portion and are arranged to admit the air into the drying chamber (10) and to which leads at least one inlet duct (35) for incoming air flow, and, on the other hand, one or more outlet openings (12, 13), which are arranged in the top of the wall portion to discharge the air from the drying chamber and from which lead one or more outlet ducts (32, 33) for outgoing air flow, whereby the air is made to flow in a plurality of flow loops, distributed in the drying chamber, between each inlet opening and the high-situated outlet openings.

3. Drying cabinet according to Patent Claim 2, characterized in that both the inlet duct (35) with inlet openings (14, 28) and outlet ducts (32, 33) with outlet openings (12, 13) are integrated in the rear wall portion (3).

4. Drying cabinet according to Patent Claim 3, characterized in that the rear wall portion (3) is made up of an outer back wall (34), and an inner back wall (36) situated with a gap (35) thereto, whereby both the inlet duct (35) and the outlet ducts (32, 33) are formed in the gap, separated by means of partition walls (37-40).

5. Drying cabinet according to Patent Claim 4, characterized in that the inlet duct (35) is constituted by a centrally situated, vertically extending duct, which is surrounded by the outlet ducts (32, 33) situated on either side.

6. Drying cabinet according to Patent Claim 4 or 5, characterized in that the inlet ducts (14, 28) are constituted by horizontal slit openings in the inner back wall (36), which has guide members, arranged to guide the air flows inwards and downwards into the drying chamber (10).

7. Drying cabinet according to Patent Claim 6, characterized in that the outlet ducts (12, 13) are constituted by holes, situated exclusively in the top of the inner back wall (36).

8. Drying cabinet according to any one of the preceding patent claims, characterized in that the outlet ducts lead to a fan/condenser assembly (8) in which the air is dehumidified by condensation.

9. Drying cabinet according to any one of Patent Claims 4-8, characterized in that the outer back wall (34) extends down to the lower bottom wall (43) of the outlet box (44/66), the inlet duct (31 ) extending through, but being shielded from, the outlet box.

10. Drying cabinet according to Patent Claim 1 , characterized in that one or more filter units (67) for cleaning of the outlet air are situated in the outlet box (66).