[0001] This invention relates to an improved method for cleaning ventilation ducts.
[0002] Until now such cleaning has been carried out by means of sweep-brooms which in a
way known
per se have been drawn back and forth in the evacuation duct and the moisture duct. One
has also used a small "robot car" having a rotating brush and the method has been
carried out with the assistance of a camera.
[0003] However, sweep-brooms can be used only in vertical ducts. The result then being unsatisfactory
because the cleaning will be imperfect but nevertheless this method is a very expensive
and time consuming one.
[0004] The purpose of the subject invention is to provide a method which irrespective of
the construction and extension of the ducts ensures that these ducts are cleaned in
a most satisfactory way and absolutely free from germs over the whole of their lengths,
the invention making it possible to carry out the method in a more effective way
and above all in a less expensive way. This goal and other have been achieved in the
way indicated in the characterising clause of the main claim.
[0005] Other features are obvious from the sub-claims.
[0006] The invention will now be described more in detail reference being had to the drawing
showing two rooms in a building having ventilations ducts.
[0007] In the drawing there is shown a building comprising two rooms 1, 2 provided with
ventilation ducts 3, 4, 5. The ducts are connected to a common ventilation device
6 and are provided with openings 7, 8, 9, 10, 11, 12, 13, 14 and 15 for exhausting
air.
[0008] When cleaning e.g. the ventilation duct 3 one proceeds such that a suction source,
e.g. a suction car, a big ventilator, a large suction device or a dust trap is connected
by means of an attachment 16. All the openings 7, 8 and 9 are closed and a brush shaped
in accordance with the cross section of the ventilation duct 3 or adaptable to said
cross section is inserted e.g. in the opening 17 and is brought to pass with high
velocity through the ventilation duct 3. The velocity of the air may be as high as
20 - 50 meters per second, the velocity being choosed with regard had to the construction.
The brush or the bristle of the brush which by means of air is brought to pass rapidly
through the duct could be made from steel or nylon. However, it is preferable to use
first a brush provided with steel bristle, then a brush with nylon bristle, and finally
compressed air is blown through the duct in order to remove loosened dirt. If necessary,
the brush may then be used for the cleaning. As a final step the duct 3 is desinfected
by letting a desinfection device pass through the duct. Such a device is spraying
the surfaces, free of dust, with a desinfactant to kill germs that may remain on such
surfaces. Such a desinfactant may have a lasting effect and may prevent the development
of new bacteria cultures.
[0009] Should the ventilation duct at the entrance be so narrow that it is impossible to
enter the brush there one may proceed such that a nylon line is fed into the narrow
slot and the suction device is used for suction of the line to the wider entrance
at the opposite end of the ventilation duct. At this end the brush is attached to
the nylon line and is drawn to the first mentioned end of the ventilation duct whereupon
one proceeds as described in the aforegoing.
[0010] The brushes may be replaced by e.g. foam rubber balls (Type: Tapprogge) or balls
of another material or of another shape. As already mentioned the duct should, when
it is free of dirt and dust, be sprayed with a desinfactant. Such desinfactant in
excess will be removed from the suction device with the air. In many a case the desinfactant
may be replaced or completed by means of water steam which in addition may contain
a solvent so as to clean the surfaces in the duct from fatty or greasy depositions.
Nicotine may be absorbed in such fatty depositions on the walls.
[0011] The invention is of course not restricted to the shown and described embodiments
but many modifications are possible without departure from the scope of the invention
as defined in the appended claims. As already mentioned the body which by the strong
steam of air is sucked through the duct and sweeps the surface clean, be shaped in
many ways even though in the most cases a fully satisfactory result is obtained by
means of brushes. Within the scope of the invention the brushes may take many shapes
for being adapted the type of depositions in the ventilation duct.
1. An improved method for cleaning ventilation ducts, characterised by the fact that a source of vaccum is used to bring a stream of air to flow through the ventilation
duct, said stream being strong when compared with the ventilation stream of air through
the duct, that at least one cleaning element which is adaptable to the cross section
of the duct is sucked with high velocity through the duct by means of the air stream.
2. A method as claimed in claim 1, characterised by the fact that several brushes are passed through the duct, said brushes having bristles of
different stiffness, the first brush having the bristle with the highest stiffness
(e.g. steel bristle) and the last brush having the softest bristle (e.g. nylon bristle).
3. A method as claimed in claim 1 or 2, characterised by the fact that the duct after finished brushing is treated with a desinfactant.
4. A method as claimed in any of the preceeding claims, characterised by the fact that the duct is treated with water stream and/or a grease solvent.
