Conveyors: fluid current – With diverse power-driven conveyor – Rotary
Patent
1992-07-06
1994-06-28
Mitchell, David M.
Conveyors: fluid current
With diverse power-driven conveyor
Rotary
406 67, B65G 5346
Patent
active
053241428
DESCRIPTION:
BRIEF SUMMARY
This invention relates to dispensing apparatus and more particularly to dispensing apparatus for use in dispensing powdery materials which are to be entrained in a gas stream.
The dispensing of powdery materials from a storage container for entrainment in a gas stream, for example, for spraying on to a substrate, can generally be achieved by simple techniques which are well known to the art. For example, in the field of powder coatings where the powder is to be applied by spraying, the powder is stored in a hopper and the contents are made flowable or fluidized by means of air which enters the hopper at its base and forces its way up through the mass of powder. When conditions are optimized, the powder will behave as a fluid which can then be pumped from the hopper by any convenient means. Any tendency of the powdery materials to stick together and not fluidize efficiently can be overcome by using dry fluidizing gases.
This method works well for powdery materials which are not especially hygroscopic (most coating powders fall into this category) but not so well for materials which are appreciably hygroscopic. A recent example of such a powder is sodium diacetate which is proposed to be sprayed on to non-frozen meat to preserve it- this is described in pending PCT published application WO 90/03118. The dispensing apparatus described hereinabove for use with powder coating does not work efficiently when hygroscopic materials are used. The prior art on the handling of hygroscopic materials is varied. It includes such apparatus as that of SU 961745 wherein there is described the use of a series of stirring vanes rotating in a horizontal plane in conjunction with an upward flow of drying air, and that of AU-A-4591/78 wherein a hopper containing hygroscopic material is constantly jarred to stop the material sticking together and to the walls of the hopper. However, neither of these solve the problem posed by the new technology of WO 90/03118, and a need exists for a simple apparatus which can be used without the need for dry gas or other facilities not normally present at meat works.
There has now been devised an apparatus for dispensing powdery materials which is especially useful in the dispensing of hygroscopic materials. There is therefore provided, according to the present invention, an apparatus adapted to dispense powdery materials such that they may be entrained in a gas stream, the apparatus comprising the following elements in combination: which are rotatable in a substantially horizontal plane about substantially vertical axes and which sets of vanes are arranged such that they are vertically disposed of each other, such that they are separated from each other by a horizontal partition and such that the areas swept by the two sets at least partially overlap when viewed in plan, the powdery material passing from the upper of the two sets of vanes to the lower set by means of at least one communication conduit in the horizontal partition whose total cross-sectional area lies substantially within the area swept by the upper set and is at most one quarter of that swept area; and conduit through which the powdery material leaves the container, the total surface area of the exit conduit lying completely within the area swept by the lower set and being at most one quarter of that swept area, the exit conduit being so positioned in relation to the communication conduit that, when viewed in plan, there is no overlap of the cross-sectional areas thereof.
The receiving member may be any suitable member. Typically, it is a simple hopper of the type used for powder coatings, modified at the lower end to interface with the upper set of the two sets of vanes.
The container which is below this member has two sets of vanes which are vertically displaced from each other and are rotatable in a substantially horizontal plane about substantially vertical axes. Preferably the two sets of vanes share a common axis and more preferably they are rigidly mounted on a common shaft. The two sets of vanes sweep circular areas whic
REFERENCES:
patent: 1207832 (1916-12-01), Allington
patent: 1764998 (1930-06-01), Bailey
patent: 1772290 (1930-08-01), Rosencrants
patent: 2314031 (1943-03-01), Colburn
patent: 3076580 (1963-02-01), Heath
patent: 3161442 (1964-12-01), Reed
patent: 4376600 (1983-03-01), Egli
patent: 4681484 (1987-07-01), Egger
patent: 4747524 (1988-05-01), Krambrock
patent: 4808042 (1989-02-01), Muehlberger et al.
Patent Abstracts of Japan, M-254, p. 41, JP, A. 58-135030, (Sankou Kiuki Souchi K.K.) Aug. 11, 1983.
Mitchell David M.
Pike Andrew C.
LandOfFree
Two-rotor powder dispensing apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Two-rotor powder dispensing apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Two-rotor powder dispensing apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2374075