Abrading – Machine – Sandblast
Patent
1993-09-29
1995-06-27
Rachuba, Maurina T.
Abrading
Machine
Sandblast
451 91, 451 38, B24C 500
Patent
active
054275652
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method and a device for cleaning fan impellers, said device comprising at least one compressed air cannon for directing shots in the form of pulses of compressed air towards the impeller blades or other parts of the impeller, subjected to deposits.
BACKGROUND ART
In Swedish Patent Application No. 8902335-2 a method and a device is described for producing a shock wave by means of a compressed air cannon to unstick deposits on fan impeller blades. This technique is applicable to fans used under heavy environment conditions, like in dusty spaces such as in kilns of cement plants where deposits of dust on the impellers can cause severe vibration problems. FIG. 1 shows an example of a device according to this prior art with a compressed air cannon disposed at the fan inlet.
In some applications the hardness of the deposits on the blade surfaces will be so high that the deposits can not be efficiently removed by pulses of compressed air.
DISCLOSURE OF THE INVENTION
The purpose of the present invention is to improve the efficiency of removing such hard deposits from impeller blades or other parts of a fan impeller.
This purpose is obtained by a method according to claim 1 and a device according to claim 6.
According to the invention hard deposits are removed by throwing bursts of solid material towards the impeller blades or other parts of the impeller, subjected to deposits.
According to advantageous embodiments of the method according to the invention the bursts of solid material are thrown periodically or are controlled as a function of the level of vibration of impeller bearings.
According to another advantageous embodiment of the method according to the invention the bursts of solid material are thrown towards diametrically opposite blades of the impeller by means of two compressed air cannons to avoid excessive unbalance due to unsticking of the deposits.
According to still another advantageous embodiment of the method according to the invention the instant of shooting bursts of solid material is controlled as a function of the blade positions of the rotating impeller to provoke unsticking of deposits on the different blades in a selected order to reduce the unbalance created by this removal of deposits.
According to an advantageous embodiment of the device according to the invention the solid material is contained in a cylindrical cartridge, intended to be positioned in the outlet cylinder of the cannon, the ends of the cylindrical cartridge being closed by a material, brittle enough to be broken by the compressed air pulse. Thus the cartridge has to be of sufficient strength to keep the material during transportation, while the ends of the cartridge has to be so brittle that it is broken, when used in the air cannon, by the shot of compressed air from the cannon.
The solid material used is chosen according to the hardness of the deposits and the fans liability to become damaged. The chosen solid material must be of sufficient strength to crush the deposits and at the same time be friable enough to eliminate the risk of damage or wearing of the impeller blades or other parts of the impeller. Thus, according to still another advantageous embodiment of the device according to the invention, the solid material is formed of a coarse-grained material, the size of the grains being preferably between 5 and 50 mm, which coarse-grain material is friable without hard contents, and is preferably formed of gypsum stones.
The solid material can also comprise an explosive which will explode when hitting the impeller blades or other parts of the impeller, subjected to deposits. With such a material a still more efficient cleaning effect can be obtained.
BRIEF DESCRIPTION OF THE DRAWINGS
An exemplifying embodiment of the device according to the invention will now be described more in detail with reference to the enclosed drawings on which
FIG. 1 shows an embodiment of a device of the type used in the present invention with a movable compressed air cannon located
REFERENCES:
patent: 2807442 (1957-09-01), Ledgerwood
patent: 2972502 (1961-02-01), Jennings et al.
patent: 3854997 (1974-12-01), Peck et al.
patent: 4624689 (1986-11-01), Volk et al.
patent: 4680900 (1987-07-01), Wadephul et al.
patent: 4699665 (1987-10-01), Scharton et al.
patent: 5303510 (1994-04-01), Calkins
ABB Flakt AB
Rachuba Maurina T.
LandOfFree
Method and device for cleaning fan impellers does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and device for cleaning fan impellers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and device for cleaning fan impellers will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-283999