1. Field of the Invention
The present invention relates to an air-cleaning apparatus which is mounted on a wall and collects particulates within the air by means of electrical control.
2. Description of the Prior Art
The air-tight construction of offices, restaurants, recreation facilities, factories, homes and other buildings in recent years means that dust from cigarette smoke, toner from photocopiers, paper dust from photocopying paper, foul odours and other harmful substances exercise a detrimental effect on the health of persons working there, and lead to a high incidence of soiling of equipment and machinery. This has resulted in the popularisation of air-cleaning devices which are installed in offices and elsewhere in order to collect suspended particulates of toner, cigarette smoke and other pollutants from the air within the room and thus remove foul odours.
One hitherto well-known type of air-cleaning apparatus of this sort is mounted on a wall.
As may be seen from FIG. 14, a conventional wall-mounted air-cleaning apparatus comprises a pre-filter 1, an electrostatic suction-type dust-collection unit 2, a deodorising filter 3 made of activated carbon fibre or a similar material, a cross-flow fan 4, and a power supply which is not shown in the drawing. In a configuration of this sort, when the device is in operation, polluted room air 5 containing suspended particulates of toner, cigarette smoke and other pollutants is drawn in through an inlet 7 in the vicinity of the ceiling 6 by means of the suction force of the cross-flow fan 4. It first passes through the pre-filter 1, where the larger suspended particles are ensnared. It is then fed to the dust-collection unit 2, where the suspended particulates in the room air 5 are collected by imparting a corona electric charge and rendering them electrostatic. Finally it passes through the deodorising filter 3 and is purified by the adsorption and removal of any offensive odours. The purified room air 8 is expelled again by the expulsion force of the cross-flow fan through an outlet 9 in the direction of the floor 10. Thus, the room air circulates through the air-cleaning apparatus mounted on the wall 11 and is thereby purified. It may be added that the dust-collection unit 2, pre-filter 1, deodorising filter 3 and other parts are removed by opening a door 12, and cleaned for re-use when they become soiled.
However, wall-mounted air-cleaning devices are generally compact and easy to install. This means that while the inlet 7 and the outlet 9 are located respectively at the top and bottom of the device, the vertical dimension of the device as such is small. Consequently, as the drawing shows, purified air 8 expelled from the outlet 9 in the direction of the floor 10 is affected by the negative pressure which generates in the vicinity of the inlet 7, as a result of which it is unable to circulate widely within the room and returns by the shortest route to the inlet 7 in the vicinity of the ceiling 6. This has the disadvantage of rendering it impossible to remove effectively the cigarette smoke 13 and other pollutants with which the room is full.
A further disadvantage concerns the door 12 of a wall-mounted air-cleaning device. While it is true to say that one which pulls downwards with the aid of gravity is most suitable in that it allows the dust-collection unit 2 and other parts to be removed and replaced smoothly, there is a risk, as the drawing demonstrates, that if the door is opened forcefully it may come into contact with or crash into the external cover plate of the device, scraping the paint on it and on the door 12 with damaging effect to the appearance of the device.