Patent Application
20220127551
Vapor blasting practices are well established in the art. Typically, water and grit, or other liquid and small-sized particles, as case may be, are combined in a blast pot and introduced into a stream of pressurized air for forcible ejection via a directable nozzle for scouring and cleaning surfaces. A principal problem of this established method of wet air or vapor blasting is that grit particles tend to settle out of suspension in the blast solution is in the blast pot, whereby agitation or mixing of the blast pot is required to maintain suspension of the grit particles. Such mixing or agitation reduces time for blasting operations.
What is needed is a suspension medium for improved grit delivery in vapor blast operations that includes a suspending-agent additional to the water (or other liquid) in the bast pot, whereby suspension of the grit particles is maintained in the blast solution without the need for repeatedly remixing the supply or agitating the blast pot. The suspending-agent is preferably biodegradable, nontoxic, and readily available.
The present invention relates to a suspension medium for improved grit delivery in vapor blast operations, and more particularly, to a suspension medium for improved grit delivery in vapor blast operations that comprises a suspending-agent added to the blast solution to maintain suspension of grit particles by increasing the bouyancy force of the liquid and/or dispseral of the grit particles in solution.
The present suspension medium for improved grit delivery in vapor blast operations, described subsequently in greater detail, is devised to maintain suspension of grit particles in the blast solution whereby blasting operations are maintainable without requiring agitation or remixing of the blast pot over extended periods.
As used herein throughout, the term “blasting solution” is taken to mean the combination of liquid and solid materials added to a blast pot for wet air or vapor blasting operations. Most commonly, the blasting solution is contemplated to comprise water and grit particles, that is sand-sized, coarse, medium, and fine, mineral solids. For a more detailed account of example embodiments comprising the “blast solution,” please see below.
Grit is typically added to water (or other solution or liquid) to form a blast solution at a weight ratio of 1 part grit to 3 parts water. The present invention is contemplated for use across a range of such weight ratios, from 1 part grit to 1 part water (or other solution or liquid) to 1 part grit to 5 parts water (or other solution or liquid), as case may be. Other ranges of blast solution composition by weight are contemplated as in scope of the present disclosure, the inventive step of adding a suspending-agent to the blast solution to maintain increased dispersal of the grit in solution and prevent settling remaining unaffected by the general range of compositions wherein the suspending agent is mixed. It should be noted that the same effects evincible in data herein provided are reproducible by altering the concentration of the suspending agent added to the blast solution in proportion to, or relative to, the particular weight ratio of grit to water (or other solution or liquid) comprising the blast solution. The data herein presented below in discussion of the detailed description of the drawings refers to a preferred embodiment of a blast solution comprising, by weight, 1 part grit to 3 parts water. But this composition is provided for purposes of example only and should not be considered as limiting.
As used herein throughout, the term “suspending-agent” is taken to mean a substance added to the blast solution that maintains suspension of solid particles in the solution for an extended time relative the time taken for such solids to settle absent addition of the suspending-agent. As used herein throughout, the suspending-agent may increase the viscosity or density of the blasting solution, thereby to increase the buoyancy force of the solution. Alternatively, the suspending-agent may act as a dispersant or surfactant to maintain solid particulates in suspension.
In an example embodiment contemplated herein, the suspending-agent is contemplated to be a thickening agent whereby the viscosity and/or density of the blasting solution is increased and grit particles are maintained suspended in the blast solution for extended periods of time relative the time taken to settle undisturbed in blast solution absent the addition of the said suspension agent.
In an example embodiment set forth herein the suspension agent is contemplated to be xanthan gum in solution at a range of 1 to 3% by weight, and, in a preferred embodiment, about 2%. However, other ranges and other thickening agents are contemplated for use in the present invention whereby the buoyancy force of the blast solution is increased to maintain suspension of solid particles therein. It should be noted that xanthan gum is already produced at scale for industrial applications. It is biodegradable, readily available, and therefore economically efficient.
Blasting solutions having on the order of 1.5 to 2.0% suspending-agent added by weight appear to maintain suspension of 100% of sand-sized solids for a minimum of 2 hours. After 2 hours, a small proportion of settlement (approximately 5 to 10%) of solids in-use with the blasting solution having 1.5% suspending-agent is evincible. However, blasting solution having 2.0% suspending-agent maintains suspension of all solids for at least 38 hours in all trials, with the exception of blast solution having GMA XTREMEBLAST® garnet solids (see
Thus blasting solution at 1 part girt to 3 parts water and having 1.5 to 2.0% suspending-agent by weight, wherein the suspending-agent is xanthan gum, is a preferred embodiment of the present disclosure. However, such an embodiment is not intended to be limiting of the application of the novel technology herein described, various formulations of blasting solution contemplated for use between different solids for vapor blast operations. For example, where a 1.5% suspending-agent blast solution is efficacious in maintaining suitable suspension of solids in the associated blasting solution for a reasonable time, the 1.5% suspending-agent blast solution may be preferred. Thus, the present invention contemplates a variety of blasting solutions with suspending-agent concentrations matched for use with particular solids or class of solids. For example, micro-fine solids, such as VITRO® Mineral LA500 Glass Powder (at a range of between 10 and 40 μm) may be effectively suspended (with 90% solids remaining in suspension) for up to 60 hours even with 1.0% suspending-agent. Thus, the present method herein set forth contemplates a range of suspending-agent concentrations for use across particular size classes of solids, as well as compositions of blast solution by weight, typically employed in vapor blast operations.
Thus has been broadly outlined the more important features of the present suspension medium for improved grit delivery in vapor blast operations so that the detailed description thereof that follows may be better understood and in order that the present contribution to the art may be better appreciated.
Objects of the present suspension medium for improved grit delivery in vapor blast operations, along with various novel features that characterize the invention are particularly pointed out in the claims forming a part of this disclosure. For better understanding of the suspension medium for improved grit delivery in vapor blast operations, its operating advantages and specific objects attained by its uses, refer to the accompanying drawings and description.
With reference now to the drawings, and in particular
After initial agitation, each blast solution sat without agitation or mixing for up to 60 hours. Measurements were made as to the percentage of solid settling out of solution at the following intervals: 1 hour, 2 hours, 12 hours, 24 hours, 36 hours, 38 hours, 48 hours, and 60 hours. It should be noted that, absent any suspending-agent applied at all, it is known that all blast solutions settle 100% solids within one hour.
