CONDENSER TYPE TUMBLER DRYER

Abstract: In a tumbler dryer laundry, inserted in a rotatable drum (14), is arranged to be dried by means of a hot air stream circulating in a closed loop and being heated, before entering the drum (14), by heat generating means (21) and being led, after the exit from the drum, past a condenser (22) for the removal of moisture taken up from the laundry by the hot air stream. The tumbler dryer comprises a cabinet (11), closed by a door (15), in which the condenser (22) is disposed. The operative part of the condenser (22) consists of a plate-shaped metallic material which is folded to form a series of vertical channels (30, 31) along the width of the door, said vertical channels (30, 31) forming first and second channel groups of which for each pair of adjacent channels one channel (30) is referred to the first group and the other (31) is referred to the second group and the channels (30) of the first group is completely separated from the channels (31) of the second group. The hot air stream is conducted through the channels (30) of one of the groups whereas a cold air stream is conducted through the channels (31) of the opposite group. The channels (30, 31) have a mainly rectangular shape with the long sides directly adjacent to one another and the channels (30) of the group conducting the hot air are closed at the top and bottom, respectively, forming inclined portions (37, 38), the upper portion (37) of which being arranged to redirect the air stream from a vertical into a mainly horizontal direction whereas the lower portion (38) is arranged to convey condensate water towards a discharge furrow (39), or the like, disposed in the lower part of the condenser (22) at the open end of the channel, as seen in depth of said channel.

Description: Condenser type tumbler dryer The present invention refers to a condenser type tumbler dryer for drying of textiles, in particular a tumbler dryer provided with a condenser by means of which the drying air circulating in the tumbler dryer can be dehumidified. The tumbler dryer is of a kind defined more in detail in the preamble of the appending claim 1. In a tumbler dryer it is common practice to place, if included, a condenser in the lower part of the machine, below the rotatable drum. In case of a normal size tumbler dryer supported on the floor the said positioning is quite acceptable but can involve a disadvantage in a machine having, in various ways, reduced dimensions. One such tumbler dryer has a wider but shorter drum to be adapted to the corresponding type of washing machine having reduced depth as compared to a corre- sponding normal-sized washing machine. A tumbler dryer of the type referred to have been constructed also for the purpose of being placed hanging on a wall. In the tumbler dryer having reduced depth, when the drum is given a larger diameter the need arises for the condenser to be placed differently. The publication DE-A-40 32 743-Al shows such an alternative placing of the condenser, namely in the door closing an access opening for the rotatable drum. Here, the condenser is provided with a space through which a drying air stream is arranged to flow after having left the drum. A number of tubes are provided in the space and in these tubes there is a flow of cold air causing the warm air to cool and thereby giving off a great deal of the moisture taken up. The condensate flows down to the bottom of the space and is led, in any suitable way, to a condensate discharge system for storing and/or discharge to a drain. In the publication there is also described an embodiment in which the condenser has been made of folded sheet metal for the forming of a series of vertical V- shaped channels. The described embodiment with special tubes in which the cooling air is conducted involves sealing problems in connec¬ tion with the fastening of the tubes. In addition, the manufac- ture of the condenser becomes difficult and costly. The second embodiment with folded sheet metal has been described in general terms only and does not give any advice as to how such condenser is to be realized. The object of the invention is to provide a tumbler dryer with a condenser made from folded sheet metal and placed in a door intended for closing of an access opening to a rotatable drum in the tumbler dryer. The object is achieved by a tumbler dryer incorporating the characterizing features indicated in claim 1. By the invention a condenser unit for a tumbler dryer is obtained which is relatively simple in manufacture and where the sealing problems present in the known machine discussed above have ben eliminated. The invention will now be described more in detail in connection with an embodiment and with reference to the accompanying drawings, in which: Fig. 1 schematically shows a tumbler dryer for textiles according to invention; Fig. 2 shows a condenser used in the tumbler dryer of Fig. 1 and mounted in a mounting frame and seen, partly in section, from inside the door; Fig. 3 shows a vertical cross section of the door of the tumbler dryer with mounted mounting frame and conden¬ ser; Fig. 4 shows a top view of the mounting frame with the condenser, partly in section; Fig. 5 is a detail view of the area marked by a ring in Fig. 3; Fig. 6 is a perspective view of the cut-out part of the area shown in fig. 5, and Fig. 7 is a detail view of a valve disposed in the door and schematically indicated in Fig. 1. Fig. 1 schematically shows the general structure of a tumbler dryer provided with a condenser and constructed in accordance with the invention. The tumbler dryer, generally designated by 10, comprises a cabinet 11 with a front panel 12 having an opening 13 permitting access to a rotatable drum 14 provided for supporting the laundry to be dried. The opening 13 can be closed by a door 15 having a part 16 arranged to sealingly project into the opening 13. The part 16 is provided with a course filter 17 intended to separate larger particles and foreign objects. Inside the course filter a close-meshed fine filter 18 is provided (see Figs. 3 and 4) arranged to separate lint which is always present during the drying of tex¬ tiles. The drum 14 is rotated by a driving motor, not shown, and, at the same time, a stream of hot air is driven therethrough for the drying of the laundry. The stream of hot air is generated by a fan 19 sucking air from a channel 20 past a heating element 21 and pressing the heated air through the drum 14. Then, the hot air is discharged from the drum 14 and flows via the course filter 17, the fine filter 18 and past a condenser 22 provided in the door 15, as will be described more in detail below. After having passed the condensor 22 the hot air stream is led via an opening 23 and a corresponding opening 24 in the cabinet 11 back to the channel 20 where it is again sucked by the fan 19 for continued circulation. As known, during the passage of the condenser 22 the hot air stream is cooled and gives off a great deal of its inherent moisture. The condensate thus created flows down along the walls of the condenser and is collected at the lowest point in the condenser in a way to be described more in detail below. As the cooling medium in the condenser a stream of cold air is used which is generated by a fan 25 and which via a channel 26, an opening 27 in the front piece 12 and a corresponding opening 28 in the door 15 is led to the cold side of the condenser (nearest to the outer housing of the door) where it is let out to the surrounding atmosphere via openings 29 (see Fig. 3). After this general discussion of the structure and function of a tumbler dryer provided with a condenser the continued description will be devoted to the part of the tumbler dryer to which the invention is directed, namely the condenser which is most clearly apparent in Figs. 2 and 4 but parts of which are shown also in Figs. 3 and 5. The condenser 22 is of the kind made of folded sheet metal and, more specifically, of folded aluminium foil of a thickness of 0.3 mm. As well become apparent below the folded sheet metal is so well kept together that the thickness of the sheet metal can be further reduced to a value of e.g. 0.2 mm. This may involve substantial advantages as the weight can be reduced by 30%. In case of a condenser having a sheet metal thickness of 0.3 mm and a weight of 1 kg a reduction of the thickness to 0.2 mm will give a reduction of 3 hg. The shape of the condenser appears in the right part of Fig. 2 but most clearly in fig. 4. The sheet metal is folded so that a series of mainly rec- tangular channels are formed. The channels are separated into two groups, of which one group 30 is in connection with the hot air stream and the second group 31 is in connection with the cold air stream. The two groups of channels 30,31 are complete¬ ly separate from each other and to that end the respective inlet and outlet openings for the hot air and the cold air are sealed in a suitable way. The folded aluminium sheet metal in the condenser 22 is inserted in a mounting frame 32 in which it is sealed along the edges by means of a silicone type sealing agent or the like. Mechanically, the folded sheet metal is kept together by means of comb-like elements 33 which protrude into the channels 30 at the hot air side both at the upper and lower end of the condenser. The comb-like elements 33 are mounted in the mounting frame 32 and have at their root end a reduced cross so that they can easier move sideways and compensate for possible tolerances of the comb-shaped elements 33. The width of the comb-like elements 33 is slightly greater than the width of the channels 30 and the friction caused thereby contributes in giving a good fixation of the folded sheet metal in the mounting frame. As seen in Figs. 5 and 6 a strip 34 is secured by screws 35 at the lower end of the condenser. The strip is provided with additional comb-like elements 36 protruding from below into the channels 31 at the cold air side. Accordingly, as a result of the fact that the comb-like elements 33 protrude into the channels 30 of one group from the side whereas the comb-like elements 36 protrude into the channels 31 of the second group from below a very rigid fixation of the condenser 22 in the mounting frame 32 will be achieved. As seen in fig. 4 the hot air channels 30 in the condenser 22 are closed at the top and bottom, respectively, in that the two sheet metal walls forming the respective channel are pressed together so that inclined portions 37, 38 are formed. The upper inclined portion 37 is adapted to redirect the air stream from a vertical into an essentially horizontal direction whereas the lower inclined portion 38 is adapted to lead the condensate water towards a discharge furrow 39, or the like, disposed in the bottom part of the condenser. In order to tightly close the hot air channels 30 at the top and bottom, respectively, in the pressed area, designated by 40 in fig. 5, a fold is made along a line 41 which at the end of the inclined portion 37 and 38, respectively, situated nearest to the periphery of the condenser crosses the oblique line defining the respective inclined portion. After folding, the folded portion, designated by 42, is being pressed against the remaining part of the previously pressed portion 40 for the establishment of a tight joint. In this way there is prevented air leakage at the top and water leakage at the bottom. Preventing of water leakage is of crucial importance as otherwise leaking water from a door-mounted condenser can flow out on the supporting surface of the tumbler dryer. The discharge of condensate water from the discharge furrow 39 disposed in the condenser can take place in any suitable way. For example, the discharge furrow can have two sections 39a, 39b (Fig. 2) sloping from the lateral outer ends of the conden¬ ser towards a central area provided with an opening 54 directed towards a discharge channel 55 (Fig. 6) disposed in the door below the condenser, said channel 55 leading the water to an outlet tube 43 shown in Fig. 1. When the door is closed, the last-mentioned tube is adapted to be connected to a storage container 44 provided in the cabinet 11 which can be removed for discharge or be directly connected to a drain. In order to avoid remaining condensate water dripping from the door when opened, the outlet tube 43 is provided with a valve 45 shown more in detail in Fig. 7. The valve 45 has a tubular housing 46 fixed to the door 15 by screws or the like, not shown. The housing has an interior channel 47 with an discharge opening 48. The tubular housing is surrounded by an outer valve cap 49 which under influence of a spring 50 is operated so that a sealing surface 51 on the valve cap is pressed against an O- ring 52 provided in a groove in the tubular housing 46. A bellows gasket 56 prevents leakage between the housing 46 and the valve cap 49 at the end of the valve opposite the opening 48. The housing 46 is provided with a flange 53 adapted to be operated upon closure of the door pushing the valve cap 49 to the right in the figure so that the discharge opening 48 is uncovered and water can flow from the condenser 22 to the storage container 44. As the sealing area is situated outside of the discharge opening 48 leakage is completely prevented when the door is opened. With respect to the air streams through the condenser 22, as discussed above, the warm moisture-saturated air from the drum 14 of the tumbler dryer is led via the opening 13, the course filter 17 and the fine filter 18 into the lower part of the condenser where, by the lower inclined portion 38, the air is redirected upwards sweeping past the walls of the hot air channels 30. Then, the air stream reaches the upper inclined portion 37 by which the air stream is redirected into a mainly horizontal direction to be led back via openings 23 and 24 into the cabinet 11 and the channel 20 disposed therein. The cold side of the condenser is constituted by the channels 31 which, in addition to the sheet metal walls, is limited by the front panel 51 of the door. The cooling air, generated by the fan 25, enters the condenser 22 at the top via the channel 26 and the openings 27 and 28 and is then led downwards to sweep over the walls of the channels 31 after which the air leaves the cold side of the condenser through the outlet openings 29 disposed in the lower part of the door 15. The construction of a condenser for a tumbler dryer from thin plate-shaped material according to the invention in the way described offers distinct advantages. The manufacture of the condenser pack can be made in a very easy and reliable way and the closure of the channels at the hot side of the conden¬ ser can be achieved, as well, by relatively simple folding and pressing operations which result in reliably tight joints. The fixing of the condenser pack in its mounting frame by means of the comb-like elements is so efficient that even very thin foil material of aluminium can be used. In addition, the inclined portions contribute in leading the hot air stream in an efficient way through the condenser channels at the same time as the lower inclined portions facilitate the discharge of condensate water from the walls of the hot air channels.

Claims: C l a i m s 1. Tumbler dryer in which laundry, inserted in a rotatable drum ( 14) , is arranged to be dried by means of a hot air stream circulating in a closed loop and being heated, before entering the drum (14), by heat generating means (21) and being led, after the exit from the drum, past a condenser (22) for the removal of moisture taken up from the laundry by the hot air stream, said tumbler dryer comprising a cabinet (11) closed by a door (15) in which the condenser (22) is disposed, and the operative part of the condenser (22) consisting of a plate- shaped metallic material which is folded to form a series of vertical channels (30,31) along the width of the door, said vertical channels (30,31) forming first and second channel groups of which for each pair of adjacent channels one channel (30) is referred to the first group and the other (31) is referred to the second group and the channels (30) of the first group is completely separated from the channels (31) of the second group, said hot air stream being conducted through the channels (30) of one of the groups wheeas a cold air stream is conducted through the channels (31) of the opposite group, characterized in that the channels have a mainly rectangular shape with the long sides directly adjacent to one another and the channels (30) of the group conducting the hot air is closed at the top and bottom, respectively, forming inclined portions (37,38), the upper portion (37) of which being arranged to redirect the air stream from a vertical into a mainly horizon¬ tal direction whereas the lower portion (38) is arranged to convey condensate water towards a discharge furrow (39), or the like, disposed in the lower part of the condenser (22) at the open end of the channel, as seen in depth of said channel. 2. Tumbler dryer according to claim 1, characterized in that the channels are closed by a pressing of the channel walls to form the inclined portions (37,38), in the pressed area (40) a fold (42) and another pressing being made, said fold (42) being made about a line (41) which at the end of the inclined portion (37,38) situated nearest to the periphery of the condenser (22) coincides with the oblique line defining said portion (37,38). 3. Tumbler dryer according to claim 1 or claim 2, charac- terized in that the condenser (22) is disposed in a frame (32) which at the top and bottom, respectively, are provided with a first series of comb-like elements (33) adapted to protrude, perpendicular to the plane of the frame, into one group of channels (30), at least at the lower end of the frame a second series of comb-like elements (36) being provided to protrude, from below, into the opposite group of channels (31). 4. Tumbler dryer according to claim 3, characterized in that the first series of comb-like elements (33) are adapted to protrude into the channels (30) conveying the hot air whereas the second series of comb-like elements (36) are adapted to protrude into the channels (31) conveying the cold air. 5. Tumbler dryer according to claim 3 or claim 4, charac¬ terized in that the comb-like elements (33,36) have a width slightly greater than the width of the channels (30,31). 6. Tumbler dryer according to any of claims 3-5, charac¬ terized in that adjacent to their root end the comb-like elements (33,36) have a reduced cross section. 7. Tumbler dryer according to any of claims 3-6, charac- terized in that the second series of comb-like elements (36) are provided on a removably fixed part (34) having wall sections (34a) which together with corresponding wall sections (32a) disposed in the frame (32) at its lower end form two channels (39a,39b) sloping from the sides of the frame and towards its central part, said channels opening above a discharge channel (55) disposed below the condenser (22) in the door (15). 8. Tumbler dryer according to claim 7, characterized in that the discharge channel (55) connects to a short tube (43) projecting from the inner side of the door and provided with a valve (43), said tube being adapted to prevent condensate from escaping when the door is open and, when the door is closed, to establish a connection between the discharge channel (55) in the door and a system (44) provided in the tumbler dryer for draining off and /or storage of the condensate. 9. Tumbler dryer according to claim 8, characterized in that the valve (45) associated with the tube (43) is provided with a sealing element comprising an O-ring (52) or the like disposed on the tube (43) and adapted to seal against a sealing surface (51) provided on a movable part (49) sealingly en¬ closing the tube like a sleeve, said tube being closed at its end projecting from the wall and provided, at a distance from said wall, with an opening (48), the seal comprising the O-ring (52) and the sealing surface (51) being provided in the area between the closed end and the opening (48). 10. Tumbler dryer according to any of claims 3-6, charac¬ terized in that the frame (32) supporting the condenser (22) is removably fixed to the door ( 15) , preferably by a snap-in type joint.

Inventors: ENGSTRAND TOMAS LARS BIRGER, ENGSTRAND, TOMAS, LARS, BIRGER
Applicants: ELECTROLUX AB, ENGSTRAND TOMAS LARS BIRGER, AKTIEBOLAGET ELECTROLUX, ENGSTRAND, TOMAS, LARS, BIRGER
Application year: 1995
Main classification: D06F58
IPC codes: D06F58