Solid material comminution or disintegration – Processes – With application of fluid or lubricant material
Reexamination Certificate
1996-11-06
2001-03-13
Husar, John M. (Department: 3725)
Solid material comminution or disintegration
Processes
With application of fluid or lubricant material
C241S023000, C241S024300, C241S029000, C241S065000, C241S079100, C241S152200
Reexamination Certificate
active
06199778
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to recycling waste material from a glass fiberizing process and, more particularly, to processing waste glass fibers for reuse as a fiber glass batch melt ingredient or glass fiber reinforcement for composites.
BACKGROUND OF THE INVENTION
As raw material and waste disposal costs for glass fiber production escalate and environmental concerns regarding waste disposal increase, recycling waste glass fibers provides a cost effective means to decrease such costs and alleviate associated environmental concerns.
In the fiber glass industry, waste glass fibers can be produced in the fiber forming process and in subsequent processing operations, such as in the formation of yarns, fabrics, roving, chopped reinforcement and mat products. Various approaches have been used to process and recycle such waste glass fibers.
U.S. Pat. No. 5,352,258 discloses a process and apparatus which shred scrap glass fibers, dry the shredded glass fibers, remove contaminants such as metallic materials, and feed the shredded glass fibers to a glass melter. The feeder is preferably an auger feeder having a dead space at the end of the auger adjacent the melter. The dead space permits build up of shredded glass fiber material to insulate the metal auger from the heat of the melter, as discussed at column 11, lines 31-35 of the patent. The dead space has a length of around 1 to 12 inches along the longitudinal axis of the auger and before the interior of the melter, as discussed at column 13, lines 5-11.
U.S. Pat. No. 4,145,202 discloses a method for processing waste glass strands which includes the steps of cutting and draining free water from the glass strands, removing metal from the strands, drying and incinerating the strands, sieving the strands and, if the particles are too large, grinding or milling the strands to 60 to 325 mesh range.
U.S. Pat. No. 5,312,052 discloses an apparatus and method for reclaiming fiber reinforcement from cured sheet molding compounded (SMC) waste products including a roller mill assembly in which respective rollers of each roller pair are spaced apart and driven at different speeds. Each of the rollers have identical diameters and has serrations extending across the length of the roller. Each of the serrations has a cross-sectional shape in the form of a pointed tooth, as discussed at column 4, lines 4-9.
Typical grinding and milling operations are energy-intensive, have high maintenance costs and therefore are not economically desirable to include in a recycling process. Also, it is often difficult to pneumatically convey recycled glass fibers. There is a need for a system and process for recycling glass fibers which requires minimal energy input, is efficient, durable, inexpensive, and provides glass fiber material which is conveyable by pneumatic transport, compatible with the glass melt and can be sold as a product to be used to reinforce composites.
SUMMARY OF THE INVENTION
The present invention provides a system for producing glass fiber product from scrap glass fibers, the system comprising: (a) a scrap glass fiber supply comprising scrap glass fibers having a mean average length of less than about 5 millimeters; (b) a crusher positioned to receive scrap glass fibers from the scrap glass fiber supply, the crusher comprising at least one pair of rotatable, intermeshing rollers and a drive device for rotating at least one of the rollers such that each pair of rollers rotate at essentially the same speed, each roller having an outer surface comprising a plurality of protuberances which are essentially free of serrations, at least a portion of one protuberance of a first roller of the pair of rollers contacting a corresponding portion of at least one protuberance of a second roller of the pair of rollers for crushing scrap glass fibers passing therebetween to form crushed glass fibers; and (c) an air separating device positioned to receive crushed glass fibers from the crusher and separate a first portion of crushed glass fibers having a mean average length of less than about 3 millimeters and a second portion of oversize glass fibers.
Also provided is a waste material processing system comprising (a) a waste material supply comprising waste material produced by a glass fiberizing process and comprising scrap glass fibers; (b) a shredder positioned to receive waste material from the waste material supply, the shredder for shredding the waste material to form shredded waste material; (c) a moisture reducing device positioned to receive shredded waste material from the shredder, the moisture reducing device for reducing the mean average moisture content of the shredded waste material to form moisture-reduced waste material; (d) a primary crusher comprising: (1) a body comprising a cavity having a first end positioned to receive the moisture-reduced waste material from the moisture reducing device, a second end distal to the first end, and a length therebetween; (2) a rotatable screw auger positioned within the cavity of the body for crushing and conveying the moisture-reduced waste material from the first end of the cavity in a first direction toward the second end of the cavity, the auger having a first end proximate the first end of the cavity, a second end proximate the second end of the cavity, and a length therebetween; and (3) a pressurizing device for exerting a pressure ranging from about 1.38×10
4
to about 5.51×10
6
pascals upon at least a portion of the moisture-reduced waste material positioned about the second end of the auger in a direction generally opposite to the first direction in which the auger conveys the moisture-reduced waste material such that the portion of the scrap glass fibers in the moisture-reduced waste material are crushed to form crushed glass fibers having a mean average length of less than about 5 millimeters; (e) a dryer positioned to receive the moisture-reduced waste material from the primary crusher, the dryer for drying the moisture-reduced waste material to form dried waste material having a mean average moisture content of less than about 1 weight percent; (f) a separating device positioned to receive the dried waste material from the dryer, the separating device for separating the dried waste material into a first portion of dried waste material having a mean average length of less than about 5 millimeters from oversized dried waste material; (g) a secondary crusher positioned to receive the first portion of dried waste material from the separating device, the secondary crusher comprising at least one pair of rotatable, intermeshing rollers and a drive device for rotating at least one of the rollers such that each pair of rollers rotate at essentially the same speed, each roller having an outer surface comprising a plurality of protuberances which are essentially free of serrations, at least a portion of one protuberance of a first roller of the pair of rollers contacting a corresponding portion of at least one protuberance of a second roller of the pair of rollers for crushing scrap glass fibers passing therebetween to form dried crushed glass fibers; and (h) an air separating device positioned to receive the dried crushed glass fibers from the secondary crusher and separate a first portion of dried crushed glass fibers having a mean average length of less than about 3 millimeters and a second portion of oversize dried glass fibers.
Also provided is a process for recycling waste material produced by a glass fiberizing process, the process comprising the steps of: (a) crushing scrap glass fibers having a mean average length of less than about 5 millimeters in a crusher comprising at least one pair of rotatable, intermeshing rollers and a drive device for rotating at least one of the rollers such that each pair of rollers rotate at essentially the same speed, each roller having an outer surface comprising a plurality of protuberances which are essentially free of serrations, at least a portion of one protuberance of a first roller of the pair of rollers contacting a
Cannoni Ann Marie
Husar John M.
PPG Industries Ohio Inc.
Siminerio Andrew C.
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