GB2390667A

GB2390667A - A tumble dryer having a cyclone separator

Info

Publication number: GB2390667A
Application number: GB0215915A
Authority: GB
Inventors: Derek John Watts; Brian Cornelius
Original assignee: General Domestic Appliances Ltd; Merloni Elettrodomestici UK Ltd
Current assignee: Indesit Co UK Ltd
Priority date: 2002-07-10
Filing date: 2002-07-10
Publication date: 2004-01-14
Anticipated expiration: 2022-07-10
Also published as: GB2390667B; EP1380683A3; GB0215915D0; DE60331025D1; EP1380683B8; EP1380683B1; EP1380683A2; ATE455896T1

Abstract

A tumble dryer having a cyclone separator 11 for removing fluff / lint comprises a cabinet 2 having a rotatable drum 1 with an opening 3 for loading clothing, a motor 4 drives both drum 1 and a fan 5 which is disposed in a heater box 6 and contains a heater unit 7, fan 5 delivers heated air to drum 1 through an opening 8 and leaves through a duct 9 into a further duct 10 and into a volute 12 to provide tangential input into the cyclone separator 11. The air is exhausted through slots (16, fig 2) in another duct 13 to an opening in a outside wall or to a window. Cyclone separator 13 has a transparent removable cap 14 to allow visual indication of the amount of fluff collected and permits periodical emptying of the cyclone 13, and also has internal ribs and vanes (17 and 18, fig 4) to prevent fluff revolving with the cyclone air. Duct 13 may be provided with a spiral shaped profile on its periphery to help convey air in a cyclonic manner. A barrier may be provided between air leaving the drum 1 and fan 15 to prevent fluff build up on the blades of fan 15. Fan 15 may be removed and the velocity of air may be increased by fan 5. Two or more stage cyclonic separators may be provided.

Description

1 2390667

TUMBLE DRYERS

This invention relates to tumble dryers.

A tumble dryer typically consists of a rotating drum in which a load is placed, a heater, and a fan for conveying dry heated air, which has been drawn into the dryer from 5 outside the dryer, through the load. The cooler moist air leaving the drum may be vented directly to the outside atmosphere. Typically, the duct along which the moist air travels is provided with a mesh filter, accessible to the user of the tumble dryer. This mesh filter must be removed periodically for cleaning, or the performance of the dryer will be impaired.

The invention provides a tumble dryer, which includes a cyclone separator for removing fluff from the stream of drying air leaving the drum.

A more consistent flow of drying air is achieved using a cyclone separator in place of a IS mesh filter, since the latter becomes progressively impeded by fluff.

Advantageously, the cyclone separator has a removable portion accessible from the front of the dryer to enable removal of fluff. The removable portion may be laterally spaced from the opening of a duct through which the air leaving the drum is directed. In 20 this way, the cyclone separator may be arranged to receive the drying air tangentially.

If desired, a fan may be provided to increase the velocity of the drying air entering the

cyclone separator.

A tumble dryer constructed in accordance with the invention will now be described in detail, by way of example, with reference to the accompanying drawings, in which: s Figure 1 is a schematic perspective, cut away, drawing of the tumble dryer according to the invention; Figure 2 is a view from underneath, partly in section, of a part of the tumble dryer 10 including a cyclone separator; Figure 3 is a side view of the cyclone separator shown in Figure 2, seen in the direction of the arrows 3-3; 5 Figure 4 is an end view of the cap 14 shown in Figures 1 to 3; Figure 5 is an axial cross-section of the cap 14; Figure 6 shows an alternative version of the cyclone shown in Figure 3; and Figure 7 shows an alternative version of the fan IS shown in Figure 2.

Referring to the drawings, the tumble dryer consists of a rotatable drum 1 mounted in a cabinet 2, the drum having an opening 3 provided with a door (not shown) through

which the load to be dried, typically clothes which have been washed in a washing machine, have been inserted. A motor 4 drives a fan 5 in a heater box 6 containing a heater unit 7. The motor 4 may also be responsible for rotating the drum 1.

s The heated air enters the drum at the rear via an opening 8 in the dryer box 6, and passes through the load of clothes while the drum is being rotated. The cooled moist air leaves the front of the drum via a banjo-shaped duct 9, which opens in an annular slot around the mouth of the opening 3, which is of course shielded off by means of the door which is not shown. The banjo-shaped duct 9 is secured to the front of the cabinet and lo channels the cooler moist air into a duct 10 which eventually leads to the rear of the dryer. The air could for example be vented via the rear of the dryer, through a pipe in an outside wall or to a window.

As is well known, the moist air leaving the front of the drum entrains a certain amount Is of fluff which could block the duct or cause a nuisance at the outside venting position and, for this reason, a mesh filter is usually included in known tumble dryers at some point in the path of the exhausting moist air.

In accordance with the invention, a cyclone separator 11 is provided, and the moist air zo leaving the drum and travelling along duct 10 is diverted via volute 12 to provide a tangential input to the cyclone separator 11. The cyclone separator 11 removes the fluff from the air stream, which then exhausts from the rear of the appliance via duct 13, to be fed to an opening in an outside wall or to a window. A portion of the cyclone separator is removable to enable the fluff built up to be periodically removed, and the

cyclone separator has a cap 14 accessible from the front of the dryer to permit this. This will now be described with reference to Figures 2 and 3.

To build up sufficient velocity of the moist air to form a cyclone, volute 12 is provided 5 with a fan 15, which is also driven by motor 4. The moist air passing down the duct 10 in the direction of arrow A is driven by the fan in the tangential direction B. and sets up a cyclonic swirling motion C in the cyclone separator 11. The swirling motion passes down the outside wall of the cyclone separator 11 so that fluff builds up at the left-hand end as seen in Figure 3. The cap 14 (Figures 4 and 5) is provided with internal ribs 17 10 and vanes 18 to prevent the collected fluff from revolving with the cyclone air. The cap 14 is periodically removed by the user for cleaning out the fluff. The cap is transparent (but need not be) to make the amount of collected fluff visible from the exterior of the dryer. The cyclonic airflow passes down the outside wall of the device, which can if desired be conical, before exiting through slots 16 in the inner duct 13 and exhausting 5 from the rear of the machine D to the outside atmosphere. The slots 16 are kept clear of fluff by the swirling air of the cyclone passing over its surface.

Among the advantages of the dryer described are that the operating efficiency is enhanced due to the blowing fan 5 and the sucking fan 15. Also, there is no mesh filter 20 which would throttle the airflow. The airflow is never impeded by the fluff, resulting in more consistent lower air temperatures throughout the drying cycle and consistent thermostat operations. The method of removing the fluff is straightforward. The fluff is easily tipped out of the cyclone separator, whereas it is less easy to peel fluff off a mesh filter. Further, the receiving space in the cap holds more fluff than the surface of the

mesh, hence less frequent cleaning is required. The duct 4 feeding the moist air to the cylinder 10, the banjo-shaped 9 is of simple construction.

Of course, variations may be made without departing from the scope of the invention.

Thus, referring to Figure 6, the periphery of the inner duct 13 may be provided with a spiral-shaped profile 19 to help convey the air to the front of the cyclone (at the front of the dryer) in a cyclonic manner.

lo Referring to Figure 7, in an alternative version of the cyclone, a barrier 20 is provided between the flow of fluff-entrained air leaving the drum, and the fan 15, to prevent any possible fluff build-up on the blades of the fan 15. The fan is turned around compared to Figure 2 and sucks air E from inside the dryer instead of from the drum, and blows this air tangentially into the cyclone along with the air B from the drum which is is propelled by the rear fan 5. This serves to reduce the chances of fluff being deposited on the barrier 20 itself.

In another alternative, the second fan 15 can be dispensed with, and the velocity of air produced by the rear fan 5 can be increased.

Alternatively, the fan 15 may be specially chosen so that it is selfcleaning, to avoid fluff build-up.

As described the motor 4 is responsible for rotating the drum 1 and for driving the fans

S and 15. If desired, a separate single directional motor may be used to drive the cyclone fan IS. This would be advantageous in some designs of dryer in which the drum reverses periodically to prevent the clothes tangling in the drum. A single stage cyclone separator has been described, and this may well be sufficient for dryers vented to the outside atmosphere. Nevertheless, a two or more stage cyclonic separator could be provided, in the manner of two or more stage cyclonic separators used in vacuum cleaners such as in EP-A-O 018197 and EP-A-O 042723.

While the illustrated dryer is rear-venting, the design could be adapted to a front-venting to dryer.

Claims

1. A tumble dryer, which includes a cyclone separator for removing fluff from the stream of drying air leaving the drum.

2. A tumble dryer as claimed in Claim 1, in which the cyclone separator has a

removable portion accessible from the front of the dryer to permit disposal of fluff.

3. A tumble dryer as claimed in Claim 1 or Claim 2, in which the removable portion is at least partially transparent so that fluff build- up is visible from outside the tumble dryer.

4. A tumble dryer as claimed in Claim 2 or Claim 3, in which the removable portion has surfaces to prevent the collected fluff from revolving with the cyclone air.

5. A tumble dryer as claimed in any one of Claims 2 to 4, in which the removable portion is laterally spaced from the opening of a duct through which drying air leaving the drum is directed.

6. A tumble dryer as claimed in Claim 5, in which the cyclone separator is arranged to receive drying air tangentially.

7. A tumble dryer as claimed in Claim 6, in which a fan is provided to increase the velocity of the drying air entering the cyclone separator.

8. A tumble dryer as claimed in Claim 7, in which a barrier is provided to shield the fan.

9. A tumble dryer substantially as herein described with reference to and as shown in the accompanying drawings.