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(11) | EP 0 112 138 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Laundry drying equipment |
| (57) Laundry drying equipment for domestic use comprises a casing with front and back
walls (2,3) formed with guides (7) for a closed loop conveyor (8) to provide a space
into which articles to be dried are loaded via a loading opening (4) in the front
wall (2). The loop conveyor is of open mesh construction to permit entry into the
space of air heated by an air heater (20) and circulated by a fan (16) driven by a
motor (13) that also drives the loop conveyor (8). The conveyor may be of a flexible
material and constrained to follow a path of generally rectangular form providing
a flat floor (20) on which articles may be dried with the loop conveyor stationary. |
[0001] This invention relates to laundry drying equipment. Conventional forms of such equipment include the well known tumbler dryer that comprises a drum for holding articles to be dried and which is mounted in a casing of cube-like form for rotation about a horizontal axis. In such tumbler dryers, there is a considerable waste of space between the drum and the casing.
[0002] It is an object of the present invention to provide laundry equipment that makes more effective use of the space occupied by the equipment, and whose drying efficiency is high.
[0003] According to the present invention, laundry drying equipment comprises a casing having an opening through which articles to be dried are loaded into a space bounded in part by a closed loop, the closed loop being sported for movement around the opening by support means formed in or provided on front and rear support members and which co-operate with the front and rear edges of the loop to support the latter, means including an air heater for supplying heated air to the space, and, means for driving the loop round the opening.
[0004] The articles to be dried are thus loaded into an enclosure of generally box-like form with a fixed wall - the front wall - in which the loading opening is located, a second fixed wall - the rear wall - opposite to the front wall, and the closed loop located between the fixed walls. The loop may be constrained by the guides to follow a path having a lower side wall that is flat or substantially so and on to which the articles are loaded, an upper side wall and two end walls.
[0005] The closed loop may be formed from a flexible moulded plastics or elastomeric membrane or a combination of these materials, or it may be of a fabric material in combination with one or both of these materials or it may be a rigid cylinder. Alternatively, the loop may comprise a number of rigid sections hinged together to give the required degree of flexibility. The loop may have transverse vanes to assist in imparting a tumbling action to the articles during a drying operation.
[0006] Where the loop is of flexible material, it may be strengthened by cross struts to ensure that it will support without undue flexing the weight of articles loaded on to it.
[0007] The supporting guides may take the form of tracks, for example flanges moulded upon casing front and back walls. The loop may be carried by rollers which move along the track or are part of the track. Alternatively, the track may be faced with low friction material over which the edges of the loop slide. The facing may be continuous. The edges of the loop may also be faced with low friction material either continuously or in discrete areas.
[0008] Sealing means may be provided to reduce leakage of air from the space bounded by the loop in cases where air is passed directly to that space, for example via apertures in the back wall of the casing, the air being discharged from the space via a suitable outlet which may be in the loading door.
[0009] Alternatively, air may be passed into the space via perforations in the surface of the loop. In this case, the casing would be sealed, air exiting from the space via a suitable outlet or outlets which may be in the loading door or in the casing.
[0010] Preferably, the direction of movement of the loop is reversible at intervals during a drying operation to assist even drying of the articles and to reduce the "balling" of the articles that usually occurs with uni-directional movement.
[0011] In addition, a drying cycle may be provided in which the closed loop is stationary. Such a cycle is used for drying delicate articles which are laid on the flat lower side of the closed loop and are then subjected to gentle drying by passing heated air at a suitable temperature through the space.
[0012] Alternatively, the laundry drying equipment may comprise a casing having an opening through which articles to be dried are loaded into the equipment, an article supporting conveyor in the form of a flexible endless belt, supporting guides within the casing for supporting the conveyor for movement around the opening in a closed loop of generally rectangular form, means including an air heater for supplying heated air to the space bounded by the conveyor, and means for driving the conveyor along the supporting guides.
[0013] Yet again, the laundry drying equipment may comprise a casing having an opening through which articles to be dried are loaded into a shell rotatably mounted within the casing by means of support means formed in or provided on front and rear support members and which co-operate with the front and rear edges of the shell to support the latter, means including an air heater for supplying heated air to the interior of the shell, and driving means for rotating the shell.
[0014] The driving means will normally comprise an electric motor operatively coupled to the closed loop to drive the latter, for example, by being coupled to teeth moulded integrally with the closed loop.
[0015] By way of example only, embodiments of the invention will now be described in greater detail with reference to the accompanying drawings of which:
Fig. 1 is a perspective schematic view of a first embodiment in exploded form, and,
Fig. 2 is a schematic sectional view of a second embodiment.
[0016] The embodiment is of drying equipment suitable for domestic use and comprises a casing including a box-like plinth 1 and front and back walls 2, 3. Front wall 1 has a central opening 4 which is the loading opening. A drop-down door 5 is hinged to the front wall 2 to close the opening 4 when the equipment is in use.
[0017] The casing is completed by top and side walls of one-piece construction, shown in Fig. 1 at 6. The top and side walls are secured in a suitable manner to the front and back walls 2, 3 and to the plinth 1. Suitable snap fastenings may be used consolidated preferably by a limited number of screws. The walls and base of the casing may be of a suitable plastics material thereby allowing them to be produced by a moulding process. The plastics material may be glass coupled or talc filled polypropylene for example.
[0018] The opposed facing sides of the front and back walls 2, 3 are formed or provided with supporting guides of which only those in the back wall 2 are shown at 7, which constrain a conveyor 8 to follow a closed loop path with flat sides and rounded corners thereby providing a drying space, the loading opening 4 giving access to the space.
[0019] The conveyor comprises a flexible endless belt or loop 9 of an open-mesh or apertured material capable of withstanding the effect of hot air supplied to the space during a drying operation.
[0020] The loop may be of a plastics or elastomeric material of the required flexibility and able to withstand the temperatures involved or of a combination of these materials. The material may be polypropylene for example enabling the loop to be produced very economically. It could also be made from a suitable fabric with edges of a moulded plastics or elastomeric material. During the moulding process teeth 10, 11 are formed adjacent the edges of the loop 9. Spaced strengthening strips may be fixed transversely across the width of the loop on the outside surface thereof whilst to the inner surface vanes (not shown) are secured at spaced intervals.
[0021] The loop 9 is a relatively close fit around the guides in the walls 2, 3. Rollers 12 set into the guides in the vicinity of the corners facilitate movement of the loop. Alternatively, the bearing faces of the guides may be covered with a layer of a low friction material, for
example P.T.F.E..
[0022] The loop 9 is driven by an electric motor indicated schematically at 13 and located within the casing and whose output shaft carries pinions 14 that meshes with driving pinion 15 in engagement with the teeth 10, 11 at the edges of the loop 9.
[0023] The output shaft of the motor also drives a fan indicated at 16 that draws air into the casing via an inlet vent 17 in the latter. The fan is of the cross-flow type used in electric fan heaters although other forms of fan may be used.
[0024] As can be seen from Fig. 1, the lower run 19 of the loop 9 is flat and beneath this run and spaced therefrom is a heater element 20 of sheet-like form that is substantially co-extensive with the lower run 19. The element 20 is arranged to provide at least two heat outputs of different values selectable by a user as is described below. The fan 16 is so arranged as to discharge air into the space between the lower run 19 and the heater element 20.
[0025] Formed in the upper parts of the front and back walls 2, 3 are discharge vents 21 which may incorporate lint filters. The front wall 2 also carries a control switch 22 that controls energisation of the heater element 20 and a timer 23 of any suitable form that is set by a user in accordance with the desired duration of a drying cycle.
[0026] The front and back walls 2, 3 are shown as flanged and these flanges are used to secure the panels to the plinth 1 and the side and top wall unit 6 to the front and back walls. The joints between the components just mentioned are such that air can escape only from the vents 21 when the equipment is in operation. An air seal (not shown) round the periphery of the door 5 prevents escape of air from the casing via the opening 4..
[0027] As will be appreciated from Fig. 1, substantially all the air leaving the fan 16 passes through the loop 9 and then to atmosphere via the vents 21, The small clearance round the sides of the conveyor prevent any substantial volume of air from the fan 16 by-passing the conveyor.
[0028] In use, articles to be dried are loaded through the opening 4 and laid on the lower horizontal run 19 of the loop 9. The loading door 5 is then closed and the motor heating element and timer energised by suitable operation of the controls 22, 23. The heating element 20 is adapted to provide two different heat outputs, these being selectable by suitable operation of switch 22 which is a two-position switch.
[0029] The motor 13 drives the loop 9 round the closed path and this imparts a tumbling action to the article; this action being assisted by the vanes referred to above. Air from the fan 16 heated by heater 20 enters the space through loop 9, passes over and round the articles in that space and leaves via the open mesh and passes to atmosphere via the vents 21. There may also be some radiated heat from heater 20.
[0031] At the end of the time period, the user simply opens the door and removes the dried articles. The drying cycle follows conventional practice and will include, during the final stages, the so-called cold run during which the heater is de-energised and cool air circulates through the conveyor to cool the articles. Other means of controlling the duration of the drying cycle may be used, for example, means responsive to the temperature of air leaving the space.
[0032] If the user wishes to dry delicate articles, or to air articles, these are laid on the lower horizontal run 19 of the loop 9, the door 5 closed and the heater only energised at a lower level than would be the case when the impeller is operating thereby avoiding overheating of the heater. Such articles may be dried solely by radiated heat from the heater 20, i.e. the fan 16 is not energised.
[0033] Air within the casing becomes hot and a gentle circulation of air within the casing and through the space is set up thereby drying the article.
[0034] Other means of supporting and driving the loop than that described above may be used. Where necessary, seals may be fitted to prevent leakage of air past the edges of the loop and these edges may be rounded to improve the sealing.
[0035] It will be appreciated that the closed path of the loop follows closely the inside contour of the casing thereby minimising waste space. The closed path will not be geometrically rectangular but will have gently rounded ends as shown to reduce frictional resistance to movement of the loop. The ends of the loop need not be vertical but could be inclined. In addition, the lower run of the loop need not be exactly flat but may follow a gently curved path. The lower run enables a user to dry flat articles which require this type of drying.
[0036] It will also be understood that the fan and/or heater may be so arranged as to direct air through the heater prior to the air entering the space.
[0037] It is not essential to provide air exit vents in both front and back panels. It may be preferred to have a single vent in the back panel. Such a single vent may be adapted to receive a discharge duct to enable air to be discharged to the atmosphere external to the room in which the equipment is located.
[0038] In an alternative form of the construction shown in Fig. 1, the vents 21 are omitted and instead, the door 5 has an air exit fitted with a removable lint filter. In such a construction, it is also possible to supply heated air to the space from an air duct located behind the back panel which is apertured to permit entry of the air into the space. The back panel, or a part thereof, may be used to form the air duct.
[0039] The front and back panels may be structural components within a separate casing and not parts of the latter as is the case of the embodiment shown in Fig. 1.
[0040] In addition, it is possible to employ a belt drive for the loop. The drive belt passes round part of the loop in driving engagement therewith and is driven by a pulley on the output shaft of the motor. In this case, the teeth 10, 11 are omitted.
[0041] The second embodiment shown in Fig. 2 is also of drying equipment suitable for domestic use and comprises a casing (not shown) and front and back walls 25, 26. The walls 25, 26 may constitute the front and back walls of the casing or they may be internal structures within an outer casing. The walls 25, 26 may be of a moulded plastics material for example glass-coupled or talc-filled polypropylene.
[0042] Both walls 25, 26 are formed with integral flanges 27, 28 respectively which form circular tracks on which the front and rear edges of a conveyor in the form of a cylindrical shell 29 are supported in such manner that the shell is rotatable about its horizontal axis. The flanges 27, 28 may be coated or surfaced with an anti-friction material and air seals may be provided to reduce air leakage from the interior of the shell.
[0043] The front wall 25 has an opening 30 aligned but not necessarily co-extensive with the forward end of the shell 29. A closure 31 mounted upon the wall 25 or on a front panel member'of the casing is provided to close the opening 30 when the dryer is in use as will be described below. Sealing means (not shown) between the closure 31 and the panel 25 prevent unwanted escape of air.
[0044] The rear wall 26 also has an opening 32 aligned but not co-extensive with the rear end of the shell 29. Opening 32 is covered by a removable lint filter 33 supported upon a filter cover 34 that, whilst not preventing the free flow of air through the filter 8 prevents damage to the filter by articles moving around inside the shell 29 as the latter is rotated.
[0045] The shell 29 is of rigid, cylindrical, open-ended form and may be of metal or of a suitable plastics material with perforations 35 in its wall and internally extending vanes 36 which may be integral with the shell or may be separate components secured on the internal face of the shell. The vanes 36 operate in the well-known manner to impart a tumbling action to articles in the shell as the latter is rotated.
[0046] The front and rear edges of the shell 29, which may be swaged over for extra strength, rest upon the flanges 27, 28 which form, in effect, bearing surfaces to enable the shell 29 to be rotated about its horizontal axis by an electric motor (not shown) but located within the casing of the equipment. The output shaft of the motor is coupled to the shell for example by a belt in engagement with the periphery of the shell adjacent one end thereof or by means of a pinion on the shaft that is in engagement with circumferential spaced teeth on the outside surface of the shell.
[0047] The motor also drives an impeller which draws air from the atmosphere via an inlet aperture in the casing and pumps it over an electric heating element (not shown) and into the interior of the shell via the perforations 35.
[0048] To use the equipment, a user opens the closure 31 and loads articles to be dried into the shell 29 after which the closure 31 is shut and the motor energised to rotate the shell and drive the impeller. At the same time, the heater is energised and heated air passes into the shell and the articles are tumbled in the stream of heated air by the rotation of the shell and the action of the vanes 36. The air leaves the shell by the open rear end thereof and the aperture 32, the filter 33 removing fluff and other entrained matter before the air is discharged to atmosphere. In the drawing, air flow is indicated by the arrows.
[0049] At the end of a drying operation, the user opens the closure (rotation of the shell having ceased) and removes the articles.
[0050] The equipment will operate on any of the well-known drying cycles for tumbler dryers and the duration of the cycle may be time-controlled by a timer set by the user or by the value of some other variable, for example, the temperature of air leaving the shell.
[0051] In an alternative embodiment, air leaving the shell exits to atmosphere via an aperture, which may be louvred, in the closure 31 as indicated at 37 in the drawing. In this case, the rear wall 26 will not have the aperture 32 or it will be blanked off. The closure 31 will also incorporate a removable filter for filtering air before discharge to atmosphere.
1. Laundry drying equipment comprising a casing having an opening through which articles
to be dried are loaded into a space bounded in part by a closed loop, the closed loop
being supported for movement around the opening by support means formed in or provided
on front and rear support members and which co-operate with the front and rear edges
of the loop to support the latter, means including an air heater for supplying heated
air to the space, and, means for driving the loop round the opening.
2. Equipment as claimed in claim 1 in which the front support member is a front panel
member of the casng, he opening being in said member.
3. Equipment as claimed in claim 1 or 2 in which the rear support member is a rear
panel member of the casing.
4. Equipment as claimed in any one of the preceding claims in which the space is open
at both ends, the rear support member forming a closure for the rear end of the space.
5. Equipment as claimed in any one of the preceding claims in which the loop comprises
a flexible endless belt and in which the support means constrain the belt to move
around the opening in a closed path of generally rectangular form and having a lower
portion that is substantially flat.
6. Equipment as claimed in any one of claims 1-5 in which the closed loop comprises
a rigid shell of cylindrical form.
7. Equipment as claimed in any one of the preceding claims in which the support means
comprise flanges or grooves.
8. Equipment as claimed in any one of the preceding claims in which the driving means
includes a driving motor coupled to the shell via teeth on the latter.
9. Equipment as claimed in any one of the preceding claims in which the closed loop
is perforated to permit entry and exit into and from the space of air supplied to
the casing by the air heater.
10. Laundry drying equipment comprising a casing having an opening through which articles
to be dried are loaded into the equipment, an article supporting conveyor in the form
of a flexible endless belt, supporting guides within the casing for supporting the
conveyor for movement around the opening in a closed loop of generally rectangular
form, means including an air heater for supplying heated air to the space bounded
by the conveyor, and means for driving the conveyor along the supporting guides.
11. Laundry drying equipment comprising a casing having an opening through which articles
to be dried are loaded into a shell rotatably mounted within the casing by means of
support means formed in or provided on front and rear support members and which co-operate
with the front and rear edges of the shell to support the latter, means including
an air heater for supplying heated air to the interior of the shell, and driving means
for rotating the shell.