Claims
- 1. A process in which solid pellets are entrained in a stream of pressurized gas in a conduit and are propelled by the gas through a nozzle out of the conduit against a surface in which the improvement comprises:
- said particles being solid particles of a material which will sublime after engaging the surface,
- said nozzle being a supersonic nozzle contoured to maximize the flow momentum of the particles by producing a total static pressure at the exit of the nozzle which was equal to the static pressure in the surrounding environment,
- said particles are in the equipment utilized to practice said process a sufficiently short time so that no more than about 10 percent by weight is lost from said particles during the time from when said particles are introduced into the equipment for practicing the process to when said particles engage said surface.
- 2. A process as claimed in claim 1 in which:
- said particles are in the equipment utilized to practice said process a sufficiently short time so that no more than about 5 percent by weight is lost from said particles during the time from when said particles are introduced into the equipment for practicing the process to when said particles engage said surface.
- 3. A process as claimed in claim 1 wherein:
- said particles are of a tetrahedral shape and have sharp edges and corners,
- the largest dimension of said particles is from about 1/16 inch to about 3/8 inch,
- the density of said particles is at least about 90 percent of the theoretical density of said particles,
- said pressurized gas is at a pressure of from about 40 to about 200 psig.,
- said particles are in the equipment utilized to practice said process a sufficiently short time so that no more than about 5 percent by weight is lost from said particles during the time from when said particles are introduced into the equipment for practicing the process to when said particles engage said surface.
- 4. A process as claimed in claim 1 in which:
- said pellets are held in a hopper and are dispensed from said hopper into a stream of pressurized gas,
- said pellets are continuously subjected to alpha particle radiation within said hopper to an extent sufficient to prevent agglomeration within said hopper,
- 5. A process as claimed in claim 1 in which:
- said pellets are carbon dioxide pellets,
- said pellets are held in a hopper and are dispensed from said hopper into said stream of pressurized gas,
- said pellets are continuously agitated and are continuously subjected to alpha particle radiation to an extent sufficient to prevent particle agglomeration when within said hopper,
- said particles are of a tetrahedral shape and have sharp edges and corners,
- the largest dimension of said particles is from about 1/16 inch to about 3/8 inch,
- the density of said particles is at least about 90 percent of the theoretical density of said particles,
- said pressurized gas is at a pressure of from about 40 to about 200 psig.,
- said particles are in the equipment utilized to practice said process a sufficiently short time so that no more than about 5 percent by weight is lost from said particles during the time from when said particles are introduced into the equipment for practicing the process to when said particles engage said surface.
CROSS REFERENCE TO RELATED APPLICATIONS
This application sets forth and claims subject matter which was set forth and claimed in the now abandoned Calvin C. Fong U.S. patent application Ser. No. 306,154 filed Nov. 13, 1972 entitled SURFACE TREATMENT PROCESS. This application also sets forth and claims subject matter which is set forth and claimed in the now abandoned co-pending Calvin C. Fong U.S. patent application Ser. No. 509,916 filed Sept. 27, 1974 entitled METHOD OF `SANDBLASTING` WITH DRY ICE. This co-pending application Ser. No. 509,916 was co-pending with the application Ser. No. 306,154 and was a continuation in part of the application Ser. No. 306,154, now abandoned. The present application is a continuation-in-part of the co-pending application Ser. No. 509,916. The entire disclosures of both of these applications Ser. Nos. 306,154 and 509,916 are incorporated herein by reference.
US Referenced Citations (12)
Continuation in Parts (2)
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Number |
Date |
Country |
Parent |
509916 |
Sep 1974 |
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Parent |
306154 |
Nov 1972 |
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