WO2001096647A1

WO2001096647A1 - Tumbler drier with a filter device

Info

Publication number: WO2001096647A1
Application number: PCT/DK2001/000367
Authority: WO
Inventors: Marc Roar Hintze
Original assignee: Electrolux Nyborg A/S
Priority date: 2000-05-24
Filing date: 2001-05-25
Publication date: 2001-12-20
Also published as: AU6206901A

Abstract

A tumbler drier is provided with a self-cleaning filter, in that wipers for fluff are fitted to the drum in such a way that they may sweep the filter at least once per drying cycle. In the simple case it is once per revolution, according to embodiments the number of cleanings of the filter may be decided by simple means. The fibres swept off fall into a bin which does not need frequent emptying.

Description

TUMBLER DRIER WITH A FILTER DEVICE.

The invention relates to a tumbler drier comprising an air pump, a drum with apertures for the supply of dry air and exhaust of humid air, a lid for loading and emptying the tumbler drier, a filter for filtration of the air, which has passed through the drum as well as means for the removal of fluff collected by the filter, in which wiping means fitted to the surface of the drum wipe the filter surface during the rotation of the drum.

A tumbler drier of the type described above uses heated air, which enters a rotating drum and sweeps over or blows through moist laundry, which is kept in a falling motion due to the rotation of the drum. Thereby the air absorbs moisture, and the humid air is removed, either to the open air or for recirculation subsequent to condensation of the moisture content. During the last minutes of a drying cycle the clothes are nearly dry, and fluff in the form of textile fibres carried by the exhaust air are given off. These fibres may block the air passages, and they are hence collected by a filter, which is gradually clogged thereby. Dependent on the construction of the tumbler drier and the filter area there is a need for regular cleaning of the filter. Usually this is performed by opening the machine, taking out the filter unit and wiping off the layer of fluff. In heavily used machines this means an interruption of the normal functioning cycle, in particular because one cannot allow the users to perform this in commercial installations. Tumbler driers in an industrial environment must be able to handle objects left in the laundry without increased wear or damage to the tumbler drier. Such object may typically be nails or screws in working clothes, which have been forgotten in the pockets when the garments were handed in for laundering.

In the industry filters are known, which are self-cleaning, in that they are subjected to an interruption of operations, followed by a strong acceleration, whereby dust and other particles are shaken loose and fall down for collection in a bin. In electrofilters it is known to reverse the polarity of the voltage of operation, whereby dust falls off None of these methods are particularly useful for use with tumbler driers. US 1,996,253 describes a tumbler drier installation, in which the flow into and out of the drum occurs through the entire perforated cylindrical shroud. The exhaust of the air occurs through an equally cylindrical filter at the lower side, and felt-covered laths along generatrices on the rotating drum sweep the surface of this filter, so that collected fluff is pushed down into a bin below, which may be taken out and emptied. This construction has the disadvantage that the laundry must be without pointed and sharp objects, because these will be separated from the laundry during the rotation of the drum, and eventually collect at the lower part of the drum, and with the points projecting through the perforations, whereby they will damage the filter just outside the drum.

It is the purpose of the invention to provide an improved construction for a filter which enables continuous operation without interruption for the cleaning of the filter and which avoids the risk of damaging the filter. This is obtained in a construction which is particular in that the drum is provided with a ring of exhaust openings or perforations close to one end of the cylindrical part, said ring of openings cooperating with a filter placed as a part cylinder in the outer shroud, said filter being disposed along the upper half of the cylinder, so that radially directed sweeping means on the cylindrical part of the drum may be brought to sweep the inner surface of the filter during rotation of the drum. Hereby the further advantage is obtained, that all smaller components, including the filter, may all be placed so that they are accessible from the top, i.e. so that both industrial manufacture and repair may take place from above, in a good working position. For this purpose the housing of the tumbler drier will be provided with a top lid, which may be removed.

In an advantageous embodiment of the invention the sweeping means are fitted axially swingable on the cylindrical part of the drum, so that they may have an active position for wiping as well as a passive position, where no wiping takes place. If these positions are linked to the sense of rotation, this means that it becomes possible to control the number of wiping operations on the filter per drying cycle, which is less than the number that is obtained by means of a fixed fitting, where a wiping occurs once per revolution and independent on the sense of rotation. By letting most revolutions occur in a direction, during which the wiping means do not contact the filter, and by ensuring that there is a limited number of rotations in the reverse sense, there will only be sweeping in those instances.

In a further advantageous embodiment of the invention the exhaust openings are provided in the part of the drum which is nearest the lid. Hereby it is obtained that the bin for fluff is placed below the loading opening for the tumbler drier and hence in a place which is easy to reach from the front of the machine.

In a further advantageous embodiment of the invention, the exhaust openings are disposed opposite a part of the cylinder which is not perforated, whereby the filter is disposed as a section of a circle in a plane which is axially displaced with respect to the exhaust openings. The filter is hence placed in such away that pointed objects cannot damage the filter even if they were to work their way through the perforations, and the filter will hence only be touched by the sweeping means. In this way a freedom in the placement is obtained, in that the filter is not bound to be pladed at the upper part of the drum.

A further embodiment of the invention is particular in that the sweeping means may have a first position, in which they project by the force of a spring essentially radially from the drum and a second position, in which they are held by a latching mechanism essentially tangentially to the drum against the spring force. Hereby it is obtained that the two positions for the swingable sweeping means become well-defined. In a further embodiment this is utilised for the control of the cleaning of the filter, in that the sweeping means in the radially projecting position hits a pointed projection on the frame of the tumbler drier, which causes the sweeping means to be locked in the tangential position, whereby an element which is connected to the lid releases the sweeping means when the lid is acted upon. This means that without having to define a drying cycle as consisting of a number of revolutions in one sense of rotation and a particular number of revolutions in the other sense for cleaning the filter, it may be ensured that the filter is cleaned at least once per cycle. Operating the lid will cause the flicking of the sweeping means to the active position, and after the first revolution, the influence of the pointed projection has caused the sweeping means to be once again in the locked, inactive position. When the term sweeping means has been used above, it refers in most instances in practice to a brush.

The invention will be described in greater detail in the following with reference to the drawing, in which

Fig. 1 shows an embodiment of the invention in a longitudinal section,

Fig. 2 shows the same construction in a dimetric representation without a filter, and

Fig. 3 shows the same construction, but with a filter,

Fig. 4 shows a sweeping means, which is mounted swingable,

Fig. 5 shows a drum, in which the exhaust openings have been shifted axially with respect to the placement of the filter, and

Fig. 6 shows a drum placed in a shroud, in which the filter is placed as a sector-shaped part of the endplate.

In Fig. 1 is shown a section through a drum- 1 with perforations 2, a shroud 3 with a filter 4. The shroud has a channel 5 which leads into a bin 6 for fluff 7. On the drum are fitted one or several rows of brushes or scrapers 8 which once per full revolution sweep the fibres which may have deposited themselves on the filter due to the flow of the air radially outwards. This flow is caused by suction on the outside of the shroud. The flow through the drum is caused by suction through the opening 9. It will be seen that the seal between the shroud and the outer casing provides a suction space above the shroud, and that the filter 4 constitutes the only connection between the inside of the drum and the suction connection through 9. The swept-off fibres are carried downwards with the movement of the drum and finally fall into the bin 7 which may be easily removed for emptying below, the upper cover C is hinged at one edge and locked at the other edge by means of the lock L, the construction of which is immaterial to the invention. The filter 4 in Fig. 1 is shown in a position which may be termed "10 o'clock", and it will be apparent that any position between "10 o'clock" and the corresponding "2 o'clock" will be useable for performing the invention.

In Fig. 2 the view is frontal and oblique towards a partially dismantled tumbler drier. Only the upper part of the shroud 3 has been shown, because this part carries an opening 3 a, and the drum 1 may be seen both below and through the opening 3 a. In this end the drum is provided with perforations 2 in a belt close to the opening 10. When the tumbler drier is assembled this is provided with a lid which seals against false draughts. The suction through the opening 9 is performed by means of a suction apparatus 11, e.g. a centrifugal blower.

In Fig. 3 the same lay-out as in Fig. 2 is shown, however a filter has been fitted. The brushes or scrapers 8 are fitted to the outside of the drum, and they have a lenght suitable for touching the lower side of the filter, It is schematically shown how fibres and fluff fall down. It will be noted that the scraping function is independent of the sense of rotation.

In Fig. 4 is shown, how sweeping means in the shape of a brush is mounted in a fitting in order that the brush may assume a projecting or radial position, in which it is almost perpendicular to the drum and hence the filter, and a position in which it lies along the drum. In the simple embodiment rotation one way will cause the brush to be dragged tangentiaUy along and to lie down when opposite the filter in the upper part of the shroud. During rotation the other way the brush will flip out and be in an active position when it is opposite the filter.

According to an embodiment, which is not shown, the brush is spring-loaded so that it is held in its active position, unless it is flipped down, where a latch mechanism or releseable hook holds it. Release of the latch may be caused by means of a connecting rod to the hinge of the lid or a pin which is activated by the lid, whereby the brush assumes its active position due to the spring. When it has cleaned the filter it hits a projecting cam on the inside of the shroud which throws the brush back to the held position so that it is inactive until activation of the lid again flips it out. This is a sturdy construction which both ensures a long service life of the brush and the cam which provides the locking, and ensures that cleaning of the filter is performed for each drying cycle.

When fitted from new the scrapers may have a length which exceeds the distance between the drum and the filter, and they will be worn down to a suitable length. In case they just miss the filter during fluff-free conditions they will still tear off a cushion of fluff when it has formed. Hence the self-cleaning effect is ensured for a long time.

Claims

PATENT CLAIMS

1. A tumbler drier comprising an air pump (11), a drum (1) with openings for the supply of dry air and exhaust of humid air (2), a lid for loading and emptying the trumbler drier, a filter (4) for filtration of the air, which has passed through the drum (1) as well as means for the removal of fluff (7) collected by the filter, in which wiping means fitted to the surface of the drum wipe the filter surface during the rotation of the drum, characterised in that the drum is provided with a ring of exhaust openings or perforations (2) close to one end of the cylindrical part, said ring of openings cooperating with a filter (4) placed as a part cylinder in the outer shroud, said filter being disposed along the upper half of the cylinder, so that radially directed sweeping means (8) on the cylindrical part of the drum may be brought to sweep the inner surface of the filter during rotation of the drum.

2. A tumbler drier according to claim 1, characterised in that sweeping means are fitted axially swingable on the cylindrical part of the drum, so that they may have an active position for wiping as well as a passive position, where no wiping takes place.

3. A tumbler drier according to claim 1, characterised in that the exhaust openings are provided in the part (10) of the drum (1) which is nearest the lid.

4. A tumbler drier according to claim 1, characterised in that the exhaust openings are disposed opposite a part of the cylinder which is not perforated, whereby the filter is disposed as a section of a circle in a plane which is axially displaced with respect to the exhaust openings.

5. A tumbler drier according to claim 2, characterised in that the sweeping means may have a first position, in which they project by the force of a spring essentially radially from the drum and a second position, in which they are held by a latching mechanism essentially tangentially to the drum against the spring force.

6. A tumbler drier according to claim 5, characterised in that during rotation of the drum in the radially projecting position the sweeping means hit a cam projecting from the chassis of the tumbler drier, thereby influencing the sweeping means to being locked in the tangential position, whereby an element which is connected to the lid releases the latching of the sweeping means by activation of the lid.