GB2145206A

GB2145206A - Laundry drying equipment

Info

Publication number: GB2145206A
Application number: GB08322064A
Authority: GB
Inventors: John Garfield Davies; Derek John Watts
Original assignee: TI Domestic Appliances Ltd
Current assignee: TI Domestic Appliances Ltd
Priority date: 1983-08-16
Filing date: 1983-08-16
Publication date: 1985-03-20
Also published as: GB8322064D0

Abstract

A tumbler dryer has a drum-shaped shell (4) which, with a view to simplifying the construction of the dryer, is rotatably-mounted on cylindrical flanges (8) in the front and rear end walls of the drum. The flanges (8) are supported on guides (9) in the front and rear walls (1,2) of the dryer casing. The casing is formed from three structural components providing, respectively, these front and rear walls (1,2) and a base (3). The interior of the casing is divided, by a guide member (14) which partially surrounds the shell and by a partition (20), into two chambers one of which contains an impeller 12 and an air heater 13 and, in use, is at a relatively higher pressure than the other chamber. During operation of the dryer airflows from the higher-pressure chamber into the drum and is discharged from the drum into the lower-pressure chamber. <IMAGE>

Description

SPECIFICATION Laundry drying equipment This invention relates to laundry drying equipment.

Conventional forms of such equipment include the well-known tumbler dryer that comprises a drum into which articles to be dried are loaded and which is mounted in a casing for rotation about a horizontal axis. The drum has a rear wall from which extends a stub shaft that is rotatably supported in a bearing supported by a structural member of the casing. The forward end of the drum is open to enable articles to be loaded into the drum, and to this end, is rotatably supported round its periphery by another structure member of the casing. In a common construction, air is introduced into the drum via a duct system and removed from the drum along another duct system, a fan being associated with one of the duct systems to create the desired air flow.

The known arrangements are relatively complex and expensive and it is an object of the present invention to provide a simpler and cheaper arrangement.

According to one aspect of the present invention, laundry drying equipment comprises a casing having an opening through which articles to be dried are loaded into a shell rotatably mounted within the casing and having perforations around its periphery, driving means for rotating the shell, means for creating a flow of airthrough the perforated shell and a heater for heating the air flow through the shell, wherein the interior of the casing is divided into a first chamber which, in use, is at relatively high pressure and a second chamber which, in use, is at relatively low pressure, the shell defines parts of the boundaries of both the first and second chambers, and the first and second chambers together surround a major part of the periphery of the shell.

In such an arrangement, it is possible to reduce the amount of ducting employed or even to avoid the use of ducting altogether.

The air flow creating means is preferably mounted in the first chamber and may be a centrifugal impeller whose inlet is connected to an opening in the casing. In such an arrangement, it is unnecessary to provide a casing around the blades of the impeller.

The first and second chambers may share a common boundary which terminates at the periphery of the shell.

The first and second chambers may together surround substantially the whole of the periphery of the shell.

A guide member may partially surround the shell to define a path for air entering the shell. The guide member may carry the heater which may be located in the first chamber. The guide member may define part of the boundary of the first chamber and it may also define part of the boundary of the second chamber. The guide member may include a portion which is closely adjacent to or in contact with the shell; this portion, which may be in the form of a ridge, may define a boundary between the first and second chambers.

In one embodiment of the invention, the opening in the casing is on a front wall and the interior of the casing is split by the guide member into an upper part and a lower part which contains the shell and the first and second chambers. The shell is of circular cross-section and is spaced frrom the bottom, top, and side walls of the casing. The guide member overlies the upper half of the shell and spans the space between opposite side walls of the casing. A ridge projecting downwardly from the guide member to the shell extends between the front and rear walls of the casing and forms an air barrier. Another ridge projecting upwardly from the base of the casing to the shell extends between the front and rear walls of the casing and forms another air barrier. The ridges define the interfaces of the first and second chambers.

According to another aspect of the present invention, laundry drying equipment comprises a casing having an opening through which articles to be dried are loaded into a shell rotatably mounted within the casing by means of cylindrical support portions, at the front and rear of the shell, which co-operate with support guides in the casing, means including an air heater for supplying heated air to the interior of the shell, and driving means for rotating the shell.

The shell may be substantially drum-shaped with the cylindrical support portions being formed in the front and rear end walls of the drum. Alternatively, it may be substantially cylindrical, with the support portions comprising the front and rear ends of the cylinder The cylindrical shell may be rigid as described in the Specification of co-pending Patent Application No. 83.01583 or it may be formed by a flexible conveyor as described in the Specification of co-pending Patent Application No. 82.35437.

In an embodiment of the invention, in which the shell is drum-shaped, the support portion in the front end wall of the drum surrounds an opening through which articles are loaded into the drum. The correspoonding support guide is a flange surrounding the opening in the front wall of the casing.

According to a further aspect of the invention, the casing comprises three structural components, namely a base, a front wall and a rear wall. At least a part of each of these components is preferably moulded from a suitable plastics material.

By way of example, a domestic laundry dryer constructed in accordance with the invention will now be described with reference to the accompanying drawing which is a perspective schematic view of the dryer, with the casing partly exploded and with some parts removed.

The dryer has a casing including a front wall 1, a rear wall 2 and a base 3 which constitute the structural members of the dryer. Each of these structural members 1 to 3 is a moulded plastics component and the casing is completed by top and side walls (not shown) which may also be mouldings of a suitable plastics material. The front wall 1 has an opening 10 through which articles to be dried are loaded into the dryer. In use, the opening 10 is closed by a door (not shown) hinged to the front wall 1.

Rotatably-mounted within the casing is a drumshaped shell 4 having a cylindrical main portion 5 with front and rear end walls. Only the front end wall 6 of the shell 4 appears in the drawing and, as shown, it has a central opening 7 surrounded by an upstanding cylindrical portion 8. The rear end wall of the shell 4 is identical to the front end wall 6 and has the same upstanding cylindrical portion as that shown at 8.

The shell 4 is rotatably-mounted within the casing by means of the cylindrical portions 8 which cooperate with corresponding support guides in the front and rear walls 1, 2. Only the support guide 9 in the front wall apppears in the drawing and, as shown, it comprises a flange surrounding the opening 10. The rear wall 2 of the casing has a similar support guide which may extend into or around the cylindrical portion 8 on the rear end wall of the shell.

The rearwall 2 closes over the opening in the rear end wall of the shell.

The shell may be formed of metal or a suitable plastics material.

The support guides 9 on which the cylindrical supports 8 of the shell rest constitute bearing surfaces on which the shell 4 can be rotated about its horizontal axis while heated air is passed through the shell, as described below, to tumble dry the articles therein. To this end, the support guides 9 may be coated with an anti-friction material and seals may be provided to reduce the leakage of hot airfrom the interior of the shell 4. As an alternative to using the whole of the support guides 9 as the bearing surface, three or more bearing pads may be mounted on each of the support guides 9 to support the shell 4 for rotation. To impart an effective tumbling action to the articles within the shell, the latter is formed, in known manner, with internal longitudinally-extending vanes (not shown).

The shell 4 is rotated by a motor 11 which is mounted in the base 3 and the output shaft of which is coupled to the shell by a belt (not shown) which extends around the cylindrical portion 5 of the shell in driving engagement therewith. Alternatively, the motor 11 could be coupled to the shell 4 by a pinion on the motor shaft, which is in driving engagement with teeth on the outside of the shell. Preferably, the direction of rotation of the shell is reversed periodically to reduce the tendency of articles within the shell to become tangled, and to promote even drying.

An electric heating element 13 is located in a space formed between the cylindrical part 5 of the shell and a curved guide shield 14 located over the top half of the shell.

The motor also drives an impeller 12 which draws air into the casing through the back wall 2. The impeller has no casing over its blades so that its output is not confined except by other parts of the dryer as will now be described.

The impeller is located in a chamber which in use is at a pressure above atmospheric. The boundaries of the chamber are defined by the front wall 1, the rear wall 2, the base 4, the lower half of one side wall, one part of the shield 14, a ridge 16 formed on the shield 14, part of the cylindrical part 5 of the shell and a ridge 20 formed on the base; perforations 15 in the cylindrical part 5 of the shell permit the heated air in the chamber to enter the shell. The boundaries of another chamber which in use is at a relatively lower pressure are similarly defined by the front wall 1, the rear wall 2, the base 3, the lower half of the other side wall, the other part of the shield 14, the ridge 16, part of the cylindrical part 5 of the shell and a ridge 20 formed on the base 3.Air enters this other chamber from the shell via the perforations 15 and is discharged to atmosphere through a front outlet 17 or a rear outlet 18 or a bottom outlet 19 which may connect with a condensing system (not shown). It will be understood that only one of these outlets would normally be used (the other two being blanked-off) and that the flow path of the outgoing air would include the customary lint filter to remove fluff and any other entrained matter before the air is discharged to atmosphere.

The flow path of air through the dryer is indicated by the arrows 21 which show the air leaving the dryer through the front opening 17. It will be seen that the two chambers through which air passes are separated from one another by the shell and the ridges 16 and 20. A potential air leakage path between the chambers exists between the ends of the shell and the front and rear walls of the casing but this is minimised by positioning the end walls of the shell as close as possible to the casing; if a better seal is required, then a running seal extending between the ridges 16 and 20 may be attached to the front and rear walls of the casing and engage the end walls of the drum.

In use, the articles to be dried are loaded into the shell 4 through the opening 10, the door (not shown) is then closed, and the motor 11 and heater 13 are energised by operating the appropriate controls (such as that indicated at 22 on the front of the dryer). The shell 4 is rotated, by the motor lion the bearing surfaces 9 and the impeller 12 passes air through the shell as already described. At the end of the drying operation, the articles are removed from the shell 4, again through the opening 10. It will be appreciated that any of the conventional drying cycle controls may be provided to vary, for example, the length of the cycle or the temperature of the heated air passing through the shell.

The shell 4, instead of being drum-shaped as shown in the drawing, could be substantially cylindrical as described in the Specification of co-pending Patent Application No. 83.01583. In this case, the cylindrical portions 8 by which the shell is supported are the front and rear edges of the shell and the support guides 9 are flanges formed in front and back plastics mouldings which are part of the dryer casing.

Alternatively, the rigid shell 4 could be replaced by an endless flexible conveyor rotatably mounted at its front and rear ends on support guides formed in the front and back walls of the dryer casing. Such an arrangement is described in the Specification of co-pending Patent Application No. 82.35437. In this case, the shell need not have a generally circular cross section but could have a generally rectangular one whereby articles can be dried flat (i.e. without tumbling) on the floor of the shell, as described in Application No. 82.35437.

It is also not essential to all aspects of the invention for the drying air to enter and leave the shell 4 via perforations in the shell. In an alternative arrangement, the air enters the shell via perforations but leaves the shell through an opening in the rear end wall of the shell and an aligned aperture in the rear wall 2 of the casing. In a further alternative arrangement, the air leaves the shell through an aperture in the front closure (not shown) of the opening 10. Whatever arrangement is adopted, the flow path of the outgoing air includes a lint filter and a discharge duct may be provided to convey the air directly out off the room in which the dryer is located. In yet a further alternative arrangement, air does not enter the shell via perforations but through an air inlet aperture at the rear of the dryer.

The structural members 1 to 3 need not be made exclusively of plastics material. For example, the front or rear wall of the casing may comprise a generally rectangular metal pressing with a central hole on which a ring shaped plastics moulding providing the mount for the shell 4 is fixed. In the case of the front wall 1, the plastics moulding may include, for example, a hinge for the door, a support for the door catch mechanism and a lug for mounting the door micro-switch. Similarly, the base 3 may consist of a plastics frame, incorporating the ridge 20 and a mounting for the motor 11, and a thin metal plate secured to the frame and closing over any opening in the frame.

Claims

1. 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 and having perforations around its periphery, driving means for rotating the shell, means for creating a flow of air through the perforated shell and a heater for heating the airflow through the shell, wherein the interior of the casing is divided into a first chamber which, in use, is at relatively high pressure and a second chamber which, in use, is at relatively low pressure, the shell defines parts of the boundaries of both the first and second chambers, and the first and second chambers together surround a major part of the periphery of the shell.

2. Equipment as claimed in claim 1, in which the first and second chambers together surround substantially the whole of the periphery of the shell.

3. Equipment as claimed in claim 1 or claim 2, in which the first and second chambers share at least one common boundary which terminates at the periphery of the shell.

4. Equipment as claimed in any one of the preceding claims, in which a guide member partially surrounds the shell to define a path for the air that flows through the shell.

5. Equipment as claimed in claim 4, in which the guide member forms a boundary for one at least of the chambers.

6. Equipment as claimed in claim 4 or claim 5, in which a portion of the guide member forms a boundary between the first and second chambers.

7. Equipment as claimed in claim 6, in which the said portion of the guide member is a ridge projecting from the portion of the guide member that partially surrounds the shell.

8. Equipment as claimed in claim 6 or claim 7, including a partition within the casing which forms a further boundary between the first and second chambers.

9. Equipment as claimed in any one of the preceding claims, in which the air flow creating means is located in the first chamber.

10. Equipment as claimed in any one of the preceding claims, in which the heater is located in the first chamber.

11. Equipment as claimed in claim 10 when appendent to any one of claims 4 to 8, in which the heater is mounted on the guide member.

12. Equipment as claimed in any one of claims 1 to 3, in which a guide member overlies the upper portion of the shell and forms an upper boundary of the first and second chambers; a ridge projecting from the guide member towards the shell forms a boundary between the first and second chamber, and a partition member projecting from the casing towards the shell forms a further boundary between the first and second chambers.

13. Equipment as claimed in claim 12, in which the remaining boundaries of the first and second chambers are formed by the casing.

14. Equipment as claimed in claim 12 or claim 13, in which the guide member is spaced apart from the shell to define, on the first chamber side of the ridge, a passageway to direct air from the first chamber into the shell and, on the second chamber side of tthe ridge, a passageway to direct air from the shell to the second chamber.

15. Equipment as claimed in any one of the preceding claims in which the shell so cooperates with the at the front and rear thereof that leakage of air from the first to the second chamber around the shell is substantially prevented.

16. Equipment as claimed in claim 15 when appendentto any one of claims 12 to 14, including sealing means extending between the ridge and the partition member and the front and rear of the shell whereby leakage of air from the first to the second chamber around the shell is substantially prevented.

17. Equipment as claimed in any one of the preceding claims, in which the shell is supported at the front and rear thereof by support portions which co-operate with support guides in the casing.

18. Equipment as claimed in claim 17, in which the support guide(s) at the front of the shell share located around the opening through which articles are loaded into the shell.

19. Equipment as claimed in claim 18, in which the support guide at the front of the shell is a flange surrounding the opening.

20. Equipment as claimed in claim 18, in which the supports guides at the front of the shell are a plurality of bearing pads located around the opening.

21. Equipment as claimed in any one of claims 17 to 20, in which the shell is substantially drum-shaped and the support portions are formed in the front and rear end walls of the drum.

22. Equipment as claimed in any one of claims 17 to 20, in which the shell is a closed loop and the support portions comprise the front and rear edges of the loop.

23. Equipment as claimed in any one of the preceding claims, in which the casing comprises three structural components providing, respectively, a base, a front wall and a rear wall of the casing.

24. Equipment as claimed in claim 23, in which part at least of each a of structural component is moulded from a plastics material.

25. Equipment as claimed in claim 23, in which at least one of the structural components is moulded from a plastics material.

26. Equipment as claimed in claim 21, in which the support portion(s) in the front end wall of the drum is/are located around an opening in that wall, through which articles to be dried are loaded into the drum.

27. Equipment as claimed in claim 21 or claim 26, in which the support portion(s) in the rear end wall of the drum share located around an opening in that wall, which opening is closed by the casing.

28. Laundry drying equipment substantially as described herein with reference to and as shown in, the accompanying drawing.