Portable cleaning and blasting system for multiple media types, including dry ice and grit

Abstract

Blast-cleaning systems are disclosed, which enable a single system to handle different classes of particulate blasting media, such as grit, powder, and dry ice, and to deliver controllable mixtures of different media types during a blasting operation. This “multi-media” system includes a hopper having two chambers or other supply assemblies that are isolated from each other, for holding two different types of blasting media. Both chambers provide their particulates to a metering control device, which supplies a compressor. For example, by combining grit with dry ice, extremely efficient cleaning can be accomplished, with greatly reduced production of solid waste. Tests have shown that combinations of dry ice (at roughly 90%) with a grit or powder can provide far greater cleaning efficiency than either media type by itself.

1 . A mechanical system suited for use in blast-cleaning of structural surfaces, comprising a hopper assembly designed to provide at least two different types of particulate blasting media to an outlet hose, wherein said hopper assembly comprises:
 a. a first media chamber, designed to hold a supply of a first particulate blasting media, and provided with a first chamber outlet for conveying said particulate blasting media to a metering supply device;   b. a second media supply subassembly, designed and suited for providing a supply of a second and different type of particulate blasting media to the outlet conduit; and,   c. an outlet conduit designed to accept and transport, simultaneously, two different types of particulate blasting media, in a manner suited for supplying both types of particulate blasting media to a metering supply device,   and wherein the mechanical system also provides an operator with means for adjusting the ratio of the two different types of particulate blasting media, during a blast-cleaning operation.   
     
     
         2 . The mechanical of  claim 1 , wherein the second media supply subassembly is designed to provide dry ice particles to a metering supply device, and wherein the device is designed to enable a blast-cleaning operation that uses a mixture of a first particulate blasting media, and a second particulate blasting media comprising dry ice particles. 
     
     
         3 . The device of  claim 1 , wherein the second media supply subassembly comprises a second media chamber that is positioned adjacent to said first media chamber, within said hopper assembly. 
     
     
         4 . The device of  claim 1 , wherein the second media supply subassembly comprises a conduit that passes through said first media chamber. 
     
     
         5 . The device of  claim 4 , wherein the conduit is thermally insulated. 
     
     
         6 . The device of  claim 1 , wherein the second media supply subassembly comprises a second hopper assembly having an outlet conduit that is coupled to said first chamber outlet. 
     
     
         7 . A method for blast-cleaning of structural surfaces, comprising the step of using a particulate blasting media mixture, wherein a first constituent of said particulate blasting media mixture comprises dry ice particles, and wherein a second constituent of particulate blasting media mixture is selected from the group consisting of powdered and grit blasting media other than water ice, and wherein the method utilizes a blast-cleaning system that enables an operator to adjust relative volumes of said first and second constituents of said particulate blasting media mixture.