Plastic article or earthenware shaping or treating: apparatus – Air felting type shaping means – Means forming running length product
Reexamination Certificate
1998-11-02
2001-12-04
Davis, Robert (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
Air felting type shaping means
Means forming running length product
C264S115000, C264S121000, C239S591000
Reexamination Certificate
active
06325605
ABSTRACT:
TECHNICAL FIELD
The present invention relates in general to the dispersion and deposition of chopped fibrous materials and, more particularly, to apparatus for collecting chopped fibers from a source of such fibers and depositing the chopped fibers on a collection surface to be processed into non-woven webs of bonded chopped fibrous materials commonly referred to as chopped strand mat. While the invention is generally applicable to a wide variety of fibrous materials including mineral and organic fibrous materials, it will be described herein with reference to glass fibers for which it is particularly applicable and initially being applied.
BACKGROUND ART
Continuous strands of fibrous material, such as glass filaments, have been collected and distributed using opposed Coanda effect surfaces to produce mats of such material used, for example, for insulation. Examples of such equipment are disclosed in U.S. Pat. Nos. 4,300,931; 4,466,819; and, 4,496,384. Such continuous strands typically are handled wet since they are coated with binder or sizing which is sprayed or otherwise applied to the strands prior to the strands being passed to the Coanda effect surfaces.
Unlike these continuous fibers, chopped fibers are dry such that there can be a substantial build up of static electricity during their processing. Accordingly, when chopped fibers are handled, equipment for suppressing or dissipating static electricity is normally provided. Unfortunately, static suppression equipment adds expense to equipment handling dry chopped fibers and can cause problems of its own in terms of maintenance.
Even so, non-woven webs of bonded chopped glass, i.e., chopped strand mat, have been produced for many years. An initial step in that production is to collect the chopped glass and deposit it onto a moving collection surface with the resulting mat of chopped glass being processed to produce the chopped strand mat. Choppers are positioned over a forming hood which surrounds the collection surface with the choppers providing chopped glass to the forming hood through openings in the top of the hood to direct a chopped glass stream toward the collection surface. Air nozzles are angled into the glass stream in an attempt to disperse the glass stream.
The amount of glass strand input to each of the choppers is adjusted and the nozzles bent in an attempt to evenly distribute the chopped glass on the collection surface. The collection surface is foraminous and has air drawn through it to assist in the even distribution of the chopped glass and to draw the glass to the collection surface. Unfortunately, these efforts to achieve uniform fiber distribution on the collection surface are not always successful.
There is, thus, a need for improved apparatus for collecting chopped fibers from a source of such fibers and depositing the chopped fibers on a collection surface such that the chopped fibers are evenly distributed and thereby better able to be processed into chopped strand mat. Preferably, such apparatus would overcome problems with turbulent air flow in the forming hood and static electricity which are associated with existing chopped fiber handling.
DISCLOSURE OF INVENTION
This need is met by the methods and apparatus of the present invention wherein an air amplifier and an outlet cone are associated with one another to form an air cannon which receives chopped fibers and forcefully deposits the chopped fibers on a collection surface or web moving beyond an outlet end of the outlet cone. The inner surface of the air amplifier is formed of an abrasion resistant material to prevent abrasive wear within the air amplifier. A binder is applied to the resulting mat of chopped fibers. The binder may be activated by the application of energy such as heat with the resulting treated mat being compacted, cooled and rolled up to form a chopped strand mat package. For wide mats, one or more banks each made up of at least one and preferably a plurality of air cannons extend across the moving collection web. The air cannons of a bank containing a plurality of air cannons are preferably alternately directed up-line and down-line of the web to reduce interference between the air cannons which can also be individually adjusted to vary the aimed direction of the air cannons across the web. The air cannons forcefully direct chopped fibers to the web and thereby overcome air turbulence within the forming hood and forces due to static electricity.
According to a first aspect of the present invention, an air cannon for collecting chopped fibrous material and depositing received chopped fibers on a moving collection surface is provided. The air cannon comprises an air amplifier having an inlet receiving the chopped fibers, an outlet, and an inner section defining a passage through the air amplifier extending from the inlet to the outlet. The air amplifier is driven by compressed air which enters the passage of the air amplifier through an air passageway. At least a portion of the inner section of the air amplifier is formed of an abrasion resistant material. The air cannon also comprises an outlet cone having an inlet end positioned adjacent the outlet of the air amplifier and an outlet end for directing chopped fibers onto the moving collection surface.
Preferably, substantially all of the inner section of the air amplifier is formed of the abrasion resistant material. The abrasion resistant material preferably comprises metal carbide or metal carbide coated graphite, such as titanium carbide, tungsten carbide, and chromium carbide. The abrasion resistant material may have a thickness ranging from approximately 0.0045 inches to approximately 0.0075 inches, and preferably, approximately 0.006 inches. Preferably, the microhardness of the abrasion resistant material is greater than 2500 vickers-100 g load.
The air amplifier may comprise a shell having an inner surface defining the inner section of the air amplifier. The air amplifier may alternatively comprise a shell and insert structure having an inner surface which defines the inner section of the air amplifier. Preferably, the insert structure is adhesively bonded to the shell. The shell is preferably formed of a material selected from aluminum, steel, stainless steel, plastic or glass. The insert structure may comprise a truncated cone shaped first portion and a truncated cone shaped second portion. Preferably, the first and second portions of the insert structure are separate and distinct components.
According to another aspect of the present invention, an air cannon for collecting chopped fibrous material and depositing received chopped fibers on a moving collection surface is provided. The air cannon comprises an air amplifier having an inlet receiving the chopped fibers, an outlet, and an inner section defining a passage through the air amplifier extending from the inlet to the outlet. The air amplifier comprises a shell and insert structure coupled to the shell. The insert structure has an inner surface which defines the inner section of the air amplifier. The insert structure is formed of titanium carbide and comprises a truncated cone shaped first portion and a truncated cone shaped second portion. The air amplifier is driven by compressed air which enters the passage of the air amplifier through an air passageway between the first and second portions. The air cannon also comprises an outlet cone having an inlet end positioned adjacent the outlet of the air amplifier and an outlet end for directing chopped fibers onto the moving collection surface.
According to yet another aspect of the present invention an apparatus is provided for collecting chopped fibrous material and depositing received chopped fibers on a moving collection surface. The apparatus comprises at least one air cannon. The air cannon comprises an air amplifier having an inlet receiving the chopped fibers, an outlet, and an inner section defining a passage through the air amplifier extending from the inlet to the outlet. The air amplifier is driven by compressed air which enters the passage of the
Berry Kenneth M.
Clements Christopher J.
Heisler Daniel F.
Davis Robert
Eckert Inger H.
Heckenberg Donald
Owens Corning Canada Inc.
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