METHOD AND DEVICE FOR TREATING DUCTS

PROCEDE ET DISPOSITIF DE TRAITEMENT DE CANALISATIONS

English Abstract

The invention relates to a method for cleaning ventilation ducts (2). For this purpose an underpressure is generated in the duct and a jet nozzle (13) connected to a source of fluid, for instance pressurized air (12), is guided through the duct in roughly the centre of the cross-sectional area thereof. The air jet loosens the accumulated dirt which is sucked out by the vacuum (6, 8).

French Abstract

L'invention concerne un procédé de nettoyage de canalisations (2) de ventilation, lequel consiste à produire une pression réduite dans la canalisation et à guider un ajutage (13), relié à une source de fluide, par exemple de l'air (12) sous pression, à travers cette canalisation, approximativement au centre de la section de celle-ci. Cet ajutage détache les impuretés accumulées, qui sont aspirées par le vide (6, 8).

Claims

CLAIMS
1. Method for treating the inside of a duct, in
particular a duct for ventilation, comprising the steps
of:
- generating (8) an underpressure in said duct,
and
- propelling a jet nozzle (13) by means of a
reaction thrust (15, 16, 17, 18) said nozzle being
connected to a source of fluid through a hose or the like,
characterized in that during moving said jet nozzle, said
nozzle (13) is kept roughly in the centre of the
cross-sectional area of the duct by said propelling means
(15, 16, 17, 18).
2. Method as claimed in claim 1, characterized
in that the jet nozzle (13) and said propelling means
(15, 16, 17, 18) as well are connected to a source (12)
of pressurized air.
3. Method as claimed in claim 1, characterized
in that the jet nozzle (13) and said propelling means
(15, 16, 17, 18) as well are connected to a source (12)
of pressurized air and coating material.
4; Device for performing the method as claimed
in claims 1-3, comprising a jet nozzle (13) with a rotor
part (31) and a stator part (30) and connecting means on
the jet nozzle for connection to a source of pressurized
fluid and means (15, 16, 17, 18) to propel said jet
nozzle (13) by means of a reaction thrust, characterized
in that said propelling means are formed by radially
protruding flexible hollow arms (15, 16, 17, 18)
connected to said source of pressurized fluid (13).
5. Device as claimed in claim 4, characterized
in that as seen in longitudinal direction, second roughly

Description

CA 0222l38~ l997-ll-l8
F Hw/Aw/l
PCT/EP96/01535 / 09-07-97
0~ A~D D ~ ICE FOR T~E~TING D~CTS
The invention relates to a method for treating
ducts, for instance cleaning thereo~, in particular a
duct for ventilation, comprising the steps of:
- generating an underpressure in said duct, and
- propelling a jet nozzle by means of a
reaction thrust said nozzle being connected to a source
of fluid through a hose or the like.
According to a generally known method for
cleaning air conditioning ducts, an underpressure is
10 generated in the duct system an a jet nozzle connected to
a source o~ fluid is transported through the duct. The
jet nozzle can be connected for instance to a source o~
pressurized air. With the powerful air jet accumulated
dirt in the duct is loosened and removed from the duct
15 system by means of the underpressure. The jet nozzle is
moved forward in the duct for cleaning due to the thrust
of the outflowing pressurized air.
Such a jet nozzle is known from EP-A-0 077 562.
In this known method the problem arises that
20 the jet nozzle moves forward lying on the bottom of the
duct as a consequence of the own weight of the jet nozzle
and the connecting member between the source of fluid and
the jet nozzle. This results in loss of efficiency,
particularly in ducts o~ larger diameter. It is moreover
25 di~ficult in this manner to adequately clean the enclosed
corners in rectangular ducts.
The invention provides a solution herefor in
that during moving said jet nozzle, said nozzle is kept
roughly in the centre of the cross-sectional area of the
30 duct by said propelling means.
Owing to this step the distance of the walls to
the jet nozzle is to a very large degree the same in all
~NI~D SHE~T

- CA 0222138~ 1997-11-18
directions, so that a considerable efficiency improvement
is achieved.
A device for performing the method as stated
above comprises a jet nozzle with a rotor part and a
5 stator part and connecting means on the jet nozzle ~or
connection to a source of pressurized fluid and means to
propel said jet nozzle by means of a reaction thrust,
said device being characterized in that said propelling
means are formed by radially protruding flexible hollow
10 arms connected to said source of pressurized fluid. These
arms strike with their end part against the wall of the
duct and centre the jet nozzle roughly in the centre of
the duct. The flexible arms preferably take a hollow form
and are
See further pages 2, 2a filed with our letter of 12.02.97.
ED S~Fr

CA 0222138~ 1997-11-18
PCT/EP96/01635
Encl. to my letter of Feb. 1~, 199
connected to the connecting means for the fluid. In thls
manner pressurized air is for instance also directed
through the hollow arms to the corners of the duct, so
that a sufficient cleaning takes place there also.
In order to enhance the stability of the central
guiding of the jet nozzle, a second set of arms can be
arranged as seen in longitudinal direction at a distance
from the first arms 90 that support at differing mutual
distance also takes place in longitudinal direction.
From W0 94/19118 is known a method and device for
cleaning air ducts wherein a jet nozzle connected to a
source of pressurized air is moved through a duct. The
displacement occurs by means of a rigid feed tube, where-
in during operation the jet nozzle carries out a swi~ging
movement along the inner wall of the pipe. Such a device
is not suitable for cleaning rectangular or square ducts.
Because of the uncontr~lled movement of the jet nozzle it
is moreover uncertain during operation whether all wall
parts of the pipe are subjected to the cleaning opera-
tion.
From USA 5347677 is known a construction wherein adevice for cleaning ducts is used in which a blow-out
piece is moved through the duct over wheels or a suitable
frame. Air is blown from cleaning elements, wherein the
cleaning elements perform a sine-shaped movement through
the duct during operation.
USA 5109567 describes a device for cleaning air
ducts, wherein a nozzle with radially protruding arms is
rotated in the duct. The nozzle is connected to a hose
which is pulled through the duct. Flexible spacers hold
the rotating nozzle with the arms at a distance from the
walls of the duct for cleaning.
~ t~r~.~~'~a ''~

CA 0222138~ 1997-11-18
2a
SU-A-919 768 discloses a device which is self-
propelling by means of nozzles 5. By changing the angle
5 of inclination of the jet to the walls cleaning quality
is improved. This device does not disclose means for
keeping the jet nozzle substantially in the middle of the
duct to be cleaned.
EP-A-O 274 831 discloses a method for treating
10 the air passage of an air conditioning system by
introducing an air-borne mist into the air passage in
order to coat the surface of the duct. No means for
moving an air jet into the air conditioning system and
keeping the jet nozzle substantially in the middle of the
15 duct are disclosed.
The invention is.further elucidated with reference
to the drawings of embodiments.
In the drawing:
Figure 1 shows schematically the method according to
the invention,
Figures 2-4 show details of the method and device
according to the invention, and
~'r~'~ S.~-~

CA 0222138~ 1997-11-18
W 09"3~14- P~lirl~ lol63
Figures 5-7 show in perspective view with cut-away
parts embodiments of the jet nozzle according to the
invention.
An air duct system 1 for cleaning comprises a main
duct 2 and a number of side ducts, for instance 3, 4.
Prior to cleaning, the grid in the side ducts is covered
with cover foil 5. The closing member 7 in one of the
openings of the main duct is also removed and the opening
6 is connected onto an installation 8 for generating
underpressure. Connected to this installation is a dis-
charge device 9 for dust 9. The cleaning device 11 is
placed into the duct through a second small opening 10 in
the main duct 2. The device 11 is connected to a source
12 of pressurized air. The device 11 comprises a jet
nozzle 13 which is connected via the flexible hose 14 to
the pressurized air source 12. Figure 5 shows in detail
the construction of the jet nozzle.
As shown in figures 2-4, the jet nozzle is supported
by means of flexible arms 15, 16, 17, 18 such that the
jet nozzle 13 is situated roughly in the centre of the
duct. Due to the thrust of the outflowing pressurized air
the jet nozzle is moved in the direction of the arrow 19.
Air jets are emitted radially from the jet nozzle as
according to arrow 20, whereby the accumulated dirt in
the duct is loosened. Due to the underpressure resulting
from the device 8 the dirt is sucked out of the duct to
the discharge device 9 in the direction of the arrows 21,
22. The radially protruding arms take a hollow form and
are connected to the connecting means of the jet nozzle
for fluid under pressure, for instance pressurized air.
The corners of the duct are hereby also influenced by the
outflowing air and thus cleaned adequately.
Figure 2 shows a duct of relatively large cross
section. Figure 3 shows a duct of considerably smaller
cross section. This results in the arms being bent fur-
ther than in the duct of fig. 2.
Figure 4 shows a duct of very limited cross section.
These embodiments show that in principle ducts with
a wide range of inner diameters can be cleaned in this
manner.

CA 0222138~ 1997-11-18
W O~G~l~ P~l/~ '01635
In order to increase stability still further a
second set of radially protruding arms 23, 24, 25, 26 can
be arranged at a distance from the first set of arms 15,
16, 17, 18. The two sets are connected by a connecting r
member 27 of limited flexibility.
It is noted that during withdrawal of the jet nozzle
after cleaning, the arms can fold over such that the end
parts thereof lie in a direction opposed to the position
shown in figures 2-4.
Figure 5 shows details of the construction of the
jet nozzle. The jet nozzle consists of a stationary part
30 and a rotating part 31. Connected to a stationary part
30 are the aforementioned arms 15, 16, 17 and 18. The
pressurized air flows in the direction of the arrows
through the stator part 30 and the arms 15, 16, 17 and
18. Pressurized air also moves to the rotating part 31.
By choosing the inclination of the outflow channels in a
suitable manner, the rotor 31 can be provided with a
rotating movement. Figures 6 and 7 show different direc-
tions of the outflow channels. The rotating part can be
mounted by means of a water bearing as designated with
the reference numeral 32 which indicates a groove-like
opening between the relevant parts.
*****

Representative Drawing