GB2299769A

GB2299769A - Air cleaner with slidably removable filter elements

Info

Publication number: GB2299769A
Application number: GB9507450A
Authority: GB
Inventors: Andre Kuijper
Original assignee: Philips Electronics UK Ltd
Current assignee: Philips Electronics UK Ltd
Priority date: 1995-04-11
Filing date: 1995-04-11
Publication date: 1996-10-16
Anticipated expiration: 2015-04-11
Also published as: GB2299769B; GB9507450D0

Abstract

An air cleaner comprising a casing 10 having an inlet 16, an outlet 26 and a fan 14, has removable filter elements 22,24 slidably mounted in a direction transverse to the air flow. The filter elements have resilient seals 38 and tapered cam surfaces 40,42 to apply pressure to the seals. The seals may be full-length (Fig 1) or in the form of protrusions (64,66, Fig 2).

Description

DESCRIPTION AN AIR CLEANER This invention relates to an air cleaner having particular, but not exclusive, application to the cleaning of air in homes and offices. The invention also relates to a replaceable filter element for use in the air cleaner.

The principle of operation of simple air cleaners is well known. A motor-driven fan draws or blows air through a filter to remove particles and give an output of cleaned air. Different filter materials are used, depending on whether the cleaner is intended to remove mainly grit, pollen, tobacco smoke or other particles. By use of appropriate material, smells may also be removed. In time, however, the filter becomes clogged with the particles it has removed or otherwise exhausted. In some cases the filter is removable to allow it to be washed and reused, but generally the filter must be replaced once it deteriorates in effectiveness.

In known air cleaners, the filter element is placed in its casing without sealing; an access door is used to keep the filter in position, but inevitably some air bypasses the filter and reduces its effectiveness.

It is an object of the present invention to provide an air cleaner which ameliorates the known disadvantages.

According to the invention, an air cleaner comprises a casing having an air inlet and an air outlet; flow means for causing air to flow between the inlet and the outlet; and a removable filter element located in the air path between the inlet and the outlet, in which the removable filter element is slidably mounted in a direction transverse to the air flow.

Preferably the filter element has a sealing face transverse to the air flow and means are provided to apply pressure to the filter element in a direction parallel to the air flow. Optionally a resilient seal is provided on the sealing face.

Preferably the means to apply pressure to the sealing face comprises first engagement means on the filter element and being slidably engageable with second engagement means on the casing, at least one of the first and second engagement means being tapered at a small angle to the direction of the sliding movement, whereby pressure is applied progressively to the sealing face as the filter element slides into the casing. Optionally the pressure is applied only towards the end of the sliding movement with the result that the full force is applied to the resilient seal only over the final part of the insertion of the filter into the housing.

Optionally the first and second engagement means each comprise a pair of continuous guide surfaces all tapered at the same small angle, which is typically 7 1/2 degrees. Alternatively the second engagement means comprises a pair of continuous guide surfaces and the first engagement means comprises a plurality of pairs of progressively tapered guide surfaces.

Preferably the removable filter element is provided in the outlet of the flow means, which is preferably a motor-driven fan.

Optionally there are two or more removable filter elements.

Optionally the air cleaner further comprises a rotary particle separator.

A suitable particle separator is described in European Patent No. 0 268 1 60 and an air cleaner in accordance with the present invention has been found to be particularly effective when the particle separator precedes the filter element in the air path of the cleaner.

Optionally the air cleaner yet further comprises a prefilter which may be in the form of a flexible filter strip, arranged to remove particles such as hairs.

It is an advantage of an air cleaner according to the invention that the removable filter element, the particle separator, and the prefilter may all be removed through a single access cover.

Also according to the invention there is provided a removable filter elememt for an air cleaner comprising a filter housing containg filter material; on the housing a sealing face transverse to the direction of air flow through the filter, the face optionally comprising a resilient seal; and engagement means slidably engageable with the casing whereby pressure is applied to the resilient seal when the filter is engaged with the casing.

The filter may be glass paper, or may be glass paper in association with a carbon pad filter, or any other suitable filter material or combination depending on the application. The filter housing may be a moulded plastics body, and the engagement element is optionally a guide surface arranged at a small angle to the direction of sliding movement. The surface may be continuous or broken.

The invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a view of an air cleaner with its cover and removable filter elements removed; and Figure 2 is an exploded view of a removable filter element.

In Figure 1, an air cleaner comprises a casing 10 and front cover 12.

Motor driven fan 14 draws air through an inlet grill 16 in cover 12, through a flexible strip prefilter 18 ( which removes hairs and the like), and through a rotary particle separator 20 which rotates with the fan 1 4. Air then passes upwards in the casing 10 and through twin removable filter elements 22,24, and through an outlet grill 26.

The cleaner also has a control panel 28 carrying a control knob 29 and an indicator light 30.

The removable filter elements 22,24 are slidable within corresponding apertures 32,34 in the casing 10 below the control panel.

Filter element 22 comprises a rigid plastics material housing 36 having around its lower edge a resilient seal 38. The housing also carries adjacent to its lower edge a pair of guide surfaces 40,42 which lie at a small angle to the lower edges. Filter element 24 is identical.

The casing aperture 32 is provided with a filter support face 33 having a plurality of apertures 46, and a pair of guide surfaces 48,50, which lie above and at a small angle to the filter support face 33. Aperture 34 is identical.

The small angles associated with the guide surfaces on the filter and on the casing are identical, and are typically 7 1/2 degrees.

When the filter element 22 is inserted into the aperture 32, the seal 38 slides on the support face 33; towards the end of the sliding movement the guide surfaces 40,42 on the filter and 48,50 on the casing come into contact and, as the filter is further inserted, the resilient seal 38 is pressed against the face 33 to provide a substantially air-tight join.

It is an advantage of the illustrated arrangement that the air-tight join is provided by means which are easy to manufacture, and that force is applied to the resilient seal only towards the end of the sliding movement on insertion of the filter element, so that insertion and removable are easy.

Although two filters 22,24 are shown, in some air cleaners one filter may be sufficient while in others three or more may be required.

The construction of a filter element is shown in Figure 2, together with a variation of the engagement means.

The filter 22 comprises a plastics housing 36 having a plurality of upper exit apertures 52. Adjacent aperture 52 is a carbon pad filter 56 which is in contact with a mini-pleated glass fibre filter 58 held in place in the housing by a liquid polyurethane seal 60. The housing 36 also carries the resilient seal 38 around an entrance aperture 54.

Instead of the full-length guide surfaces 40,42 as in Figure 1, the housing now carries protrusions 64,66 at the rear and front of the side visible in the Figure; the opposite side is identical. The top surfaces of the protrusions are slanted at the same angle as the guide surfaces in Fig. 1 and cooperate with the continuous guide surfaces on the casing in the same way, but may be easier to manufacture. The positioning of the protrusions at the corners of the filter housing ailows effective sealing pressure to be provided.

It is an advantage of a filter element according to the invention that it is quickly and easily removed and replaced as the filter element require cleaning or replacement, or the resilient seal 38 requires replacement.

Although the filter element 22, 24 have been described as containing carbon pads and pleated glass filters, any other filtering materials may be used as appropriate.

Claims

1. An air cleaner comprising a casing having an air inlet and an air outlet; flow means for causing air to flow between the inlet and the outlet; and a removable filter element located in the airpath between the inlet and the outlet; characterised in that the removable filter element is slidably mounted in a direction transverse to the air flow.

2. An air cleaner according to claim 1 in which the filter element has a sealing face transverse to the air flow and further comprising means to apply pressure to the sealing face.

3. An air cleaner according to claim 2 in which the sealing face comprises a resilient seal.

4. An air cleaner according to claim 2 or claim 3 in which the means to apply pressure to the sealing face comprises first engagement means on the filter element and second engagement means on the casing, the first and second engagement means being relatively slideable and at least one of the engagement means being tapered at a small angle to the sliding direction.

5. An air cleaner according to claim 4 in which the first and second engagement means each comprise a pair of continuous guide surfaces tapered at the same small angle to the sliding direction.

6. An air cleaner according to claim 4 in which the second engagement means comprises a pair of continuous guide surfaces tapered at a small angle to the sliding direction, and the first engagement means comprises a plurality of pairs of guide surfaces progressively tapered at the same small angle.

7. An air cleaner according to any one of claims 2, 3, 4, 5, or 6 in which pressure is applied to the sealing face only towards the end of the sliding insertion of the filter element into the casing.

8. An air cleaner according to any preceding claim in which the removable filter element is positioned in the outlet of the flow means.

9. An air cleaner according to any preceding claim in which there is also provided a rotary particle filter.

10. An air cleaner according to claim 9 in which there is also provided a prefilter.

11. An air cleaner according to claim 10 in which the removable filter element, the rotary filter, and the prefilter are all accessible through a single access cover.

1 2. A removable filter element comprising a filter housing containing filter material; on the housing a sealing face transverse to the direction of air flow and comprising a resilient seal; and engagement means for slideable engagement with a casing whereby pressure is applied to the resilient seal.

1 3. A filter element according to claim 12 in which the engagement means comprises at least one pair of guide surfaces tapered at a small angle to the sealing face.

1 4. An air cleaner substantially as illustrated in Figure 1.

1 5. A filter element substantially as illustrated in Figure 2.