Solid material comminution or disintegration – Processes – With application of fluid or lubricant material
Reexamination Certificate
2002-02-27
2004-08-31
Rosenbaum, Mark (Department: 3725)
Solid material comminution or disintegration
Processes
With application of fluid or lubricant material
C241S024300, C241S029000
Reexamination Certificate
active
06783088
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to glass and, more specifically, to a method of producing glass as an abrasive media and using glass as an abrasive media in cutting materials.
2. Description of the Related Art
It is known to use a waterjet system to cut a very broad spectrum of materials ranging from difficult-to-machine materials such as high strength metal alloys, ceramics, rock, glass, and composites as well as softer materials such as wood, plastic, rubber, and paper. It is also known that the waterjet is one of the most diversified systems being used today. From the trimming of titanium turbine blades for jet engines to the packaging of food products, waterjet systems have been used to cut materials.
Although a significant portion of the applications utilizing waterjet systems use only water in the cutting of softer materials, the majority incorporate an abrasive head to entrain the stream of water with an abrasive, allowing much harder materials to be cut using an abrasivejet. With the stream of water serving as the carrier, the abrasive is entrained in a high-pressure stream of water in a mixing chamber and passed through a nozzle. The nozzle in turn serves to direct the resulting slurry onto a surface of the material being cut to produce a very thin kerf in which the slurry has essentially eroded the material as it makes its traverse.
The abrasives used in abrasivejet cutting fall under the largest class of minerals found on the surface of the earth, that is, the silicates. It is known that almandite of the garnet group and to a lesser extent quartz has proven to perform best when used in abrasivejet cutting. The physical properties associated with these minerals provide the characteristics found to be most desirable in the removal of material using an abrasive action. Their Mohs hardness are comparable, with garnet ranging from 6½ to 7½ and quartz most frequently being listed as 7. Their crystal structures are angular, providing very sharp edges that greatly assist in the removal of material. Furthermore, due to the nature of the hydro-abrasive erosional process, the entrained solids can be used to cut materials considerably harder than that of the abrasive. While the erosion of a ductile material results from micro shearing or a micro extrusion mechanism, the erosion of a brittle material involves the generation of microcracks and the intergranular failure of the grains.
Though the characteristics associated with quartz are comparable to those of garnet and the price of quartz is considerably less than the price of garnet, the primary concern with quartz over the years has been silicosis. Silicosis is a disease resulting from the inhalation of crystalline silica, which causes damage to the microphages of the lungs. According to the National Safety Council, the disease depends on several factors, the most significant factor being that the silica must be in crystalline form, as with quartz, to damage the lung's tissues. As a result, any studies related to the potential use of quartz as an abrasive media have in effect ceased.
Therefore, it is desirable to use glass as an abrasive media for cutting. It is also desirable to provide a method of producing glass for use as an abrasive media for cutting. It is further desirable to use glass as an abrasive media for a waterjet system in cutting materials. Thus, there is a need in the art for a method of producing glass and using glass in cutting materials that meets these desires.
SUMMARY OF THE INVENTION
Accordingly, the present invention is a method of producing glass as an abrasive media for cutting materials. The method includes the steps of providing a glass feed stock and reducing the glass feed stock in size to produce glass particles with a high angularity and low aspect ratio. The method also includes the step of classifying the glass particles to remove at least one of coarse particles and fine particles. The method further includes the steps of size classifying the glass particles to produce an abrasive with a predetermined size classification for use in abrasivejet cutting of materials.
In addition, the present invention is a method of using glass as an abrasive for cutting materials. The method includes the steps of providing glass particles as an abrasive media with a predetermined size classification. The method also includes the steps of entraining the abrasive media in a stream of water to produce a slurry, directing the slurry onto a surface of material to be cut, and eroding a portion of the material.
One advantage of the present invention is that a method is provided for producing glass as an abrasive media and of using glass as an abrasive media for cutting materials. Another advantage of the present invention is that the method produces and uses glass, which is a silicate, in an amorphous or non-crystalline form for cutting materials. Yet another advantage of the present invention is that the method eliminates the concern of silicosis, with crushed or fractured glass being cited as merely a nuisance dust by the Occupational Safety and Health Association (OSHA). Still another advantage of the present invention is that the method fractures glass and produces an abrasive of glass particles that are very angular, displaying sharp edges as well as conchoidal fractures. A further advantage of the present invention is that the method produces glass particles as an abrasive media that are similar to a garnet abrasive. Yet a further advantage of the present invention is that the method produces fractured glass as an abrasive media to provide an inexpensive alternative to garnet in those applications that involve materials comparable to, or harder than, glass. Still a further advantage of the present invention is that the method uses fractured glass as an abrasive media in abrasivejet cutting involving softer materials such as plastic, foams, textiles, etc.
Other features and advantages of the present invention will be readily appreciated, as the same becomes better understood, after reading the subsequent description taken in conjunction with the accompanying drawings.
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Gillis James Murray
Hwang Jiann-Yang
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