Abrasive tool making process – material – or composition – With carbohydrate or reaction product thereof
Patent
1986-09-25
1987-11-24
Schmidt, Frederick R.
Abrasive tool making process, material, or composition
With carbohydrate or reaction product thereof
51436, 51320, B24C 304
Patent
active
047079517
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to an installation for dry ice blasting, i.e. an installation of the type comprising an apparatus for producing particles of dry ice or carbon dioxide ice, and a metering device for delivering a metered flow of these particles to a propelling device with which a vehicle gas conduit is provided.
As is known, the expansion of liquid carbon dioxide (CO.sub.2) produces carbon dioxide snow which may be compacted so as to form pieces of carbon dioxide ice which are sublimated with heating. The installations of the aforementioned type deliver a metered flow of small particles of carbon dioxide ice or dry ice (having a dimension on the order of about 1 to 4 mm) in the vehicle gas conduit, which permits the projection of the particles onto a surface to be cleaned.
Thus dry ice blasting is similar to sand and shot blasting processes, but the sand or the shot is replaced by particles or grains of dry ice which, after having performed their abrasive function, are sublimated.
This technique has its field of application wherever treatment effluents of the liquid or solid type would be contaminated or not recoverable on the treating site. In nuclear applications for example, treatment by means of jets of water creates problems, since the water has a residue of radioactivity and the sand becomes contaminated and must be buried; on the other hand, gaseous CO.sub.2, like most gases, may be easily decontaminated by filtration.
However, known dry ice blasting installations have not been fully satisfactory, in particular owing to the tendency of the particles of dry ice to set into a mass due to static electricity, which renders irregular the flow of the particles projected onto the surface to be treated.
An object of the invention is to provide an installation whereby it is possible to obtain a regular flow of particles in the vehicle gas conduit.
The invention therefore provides an installation of the aforementioned type, wherein said apparatus allows the particles to drop by gravity into the metering device, which is spaced from said apparatus, and the outlet of said apparatus and the parts of the installation where the particles are exposed to the surrounding atmosphere are surrounded by a cover for protecting said particles from humidity.
According to other advantageous features of the invention:
the metering device in turn allows said particles to drop by gravity into the propelling device which is spaced from the metering device, the cover surrounding the outlet of said apparatus, the metering device and the propelling device; said apparatus comprises a grinding mill and means for feeding pieces of dry ice to this mill.
One embodiment of the invention will now be described with reference to the accompanying drawing, in which:
FIG. 1 is a diagrammatic elevational view, with a part in section, of a dry ice blasting installation according to the invention, and
FIG. 2 is a longitudinal sectional view, to an enlarged scale, of the propelling device of this installation.
The dry ice or carbon dioxide ice blasting installation shown in the drawing mainly comprises a grinding mill 1, means 2 for feeding the mill, a metering device 3, a vehicle gas conduit 4 provided with a propelling device 5, and a metal cover 6 for protection against humidity. The elements 1 to 5 of the installation are mounted on a metal frame (not shown) fixed to the ground 7, the latter also supporting the cover 6.
The grinding mill 1 is a rod grinding mill. It includes an upper supply hopper 8 which is open at its upper end and a lower outlet conduit 9 open at its lower end.
The feed means 2 comprise a conveyor belt 10, a vibrating spout 11 which may be raised by means of a jack 12 and whose outlet is located above the hopper 8. The metering device 3 comprises a particle tank 11 provided at its lower end with a roughly horizontal outlet tube 12. A spring-screw 13 coaxial with the latter extends through the lower part of the tank 11 to the open outlet end 14 of the tube 12. A motor 15 drives in rotation the screw 13 and the st
REFERENCES:
patent: 2079854 (1937-05-01), Hartshorne
patent: 2815716 (1957-12-01), Ransohoff
patent: 3089775 (1963-05-01), Lindall
patent: 3139705 (1964-07-01), Histed
patent: 3323257 (1967-06-01), Fonti
patent: 3702519 (1972-11-01), Rice et al.
patent: 4038786 (1977-08-01), Fong
patent: 4389820 (1983-06-01), Fong et al.
patent: 4428535 (1984-01-01), Venetucci
Charles Jean-Michel
Gibot Claude
Bose Robert A.
Carboxyque Francaise
Schmidt Frederick R.
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