Apparatus and high speed method for coating elongated fibers
AssigneeBoard of Trustees operating Michigan State University
InventorsMurty N. Vyakarnam, Lawrence T. Drzal
Life of this patent
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Abstract
An apparatus and method for uniformly coating a fiber or tow of fibers (10) with a powder at relatively high speed to produce a prepreg. The apparatus uses an elongated chamber (401) in a container (400) for confining the fiber which is coated by an aerosol of powder dispensed from a powder dispensing apparatus (500) in counter-current mode. A fiber tensioning apparatus (300) for the fiber maintains the proper tensioning of the fibers spread by a speaker (201) below the fibers on roller bars (203) so that the uniformly spread fibers are fed to the chamber (401). A heater apparatus (600) fuses the powder to the fiber and then is taken up on a spool (700).
Claims25
An apparatus for coating a length of fiber with a powder which comprises:
- (a) an elongated chamber defined by inside and outside walls of a container means with openings for inlet and outlet of the fiber adjacent to opposed portions of the chamber means such that the fiber is fed vertically between the openings through the chamber without touching the walls;
- (b) a powder dispenser means with a connection to the container, wherein the dispenser means is provided with an aerosolizing means for aerosolizing a powder in a gaseous medium in the dispenser means;
- and
- (c) a nozzle means connected to a gas supply means which is directed towards the connection of the dispenser means to the container means, wherein in use the aerosolizing means aerosolizes the powder in the dispenser means and the nozzle means directs the aerosolized powder into the container means so that the powder flows over the fiber as the fiber passes through the container means.
In a system for coating a tow of fibers with a powder at a speed wherein the tow is spread, the fibers in the tow are coated with the powder, and the powder is fused to each fiber in the tow to provide a coated tow, the improvement which comprises:
- (a) a spreader means for spreading the tow of fibers;
- (b) spool for the tow of fibers controlled by a motor which maintains a tension of the tow in the spreader means between an inlet and an outlet from the spreader means;
- (c) tension sensing means which maintains a tension on the tow between the inlet and the outlet of the spreader means by regulating the speed of the spool controlled by the motor, wherein the tension sensing means is an arm over which the tow passes with a position sensor mounted thereon, wherein the sensing means regulates the speed of the motor such that the arm is maintained in a selected position and the tension on the tow is uniform.
A method for coating a length of fiber with a powder which comprises:
- (a) providing an apparatus for coating a length of fiber with a powder which comprises:
- an elongate chamber defined by inside and outside walls of a container means with openings for inlet and outlet of the fiber adjacent to opposed portions of the chamber means such that the fiber is fed vertically between the openings through the chamber without touching the walls;
- a powder dispenser means with a connection to the container, wherein the dispenser means is provided with a vibrator means for aerosolizing a powder in a gaseous medium in the dispenser means;
- and a nozzle means connected to a gas supply means which is directed towards the connection of the dispenser means to the container means, wherein in use the aerosolizing means aerosolizes the powder in the dispenser means and the nozzle means directs the aerosolized powder into the container means so that the powder flows over the fiber as the fiber passes through the container means;
- and
- (b) coating the fiber with the powder in the chamber as the fiber is fed through the apparatus.
An apparatus for dispensing a powder to a chamber in a container means for coating a length of fiber which is to be fed vertically through the chamber with a powder which comprises:
- (a) a powder dispenser means with a connection to the container, wherein the dispenser means is provided with an aerosolizing means for aerosolizing a powder in a gaseous medium in the dispenser means;
- and
- (b) a nozzle means connected to a gas supply means which is directed towards the connection of the dispenser means to the container means, wherein in use the aerosolizing means aerosolizes the powder in the dispenser means and the nozzle means directs the aerosolized powder into the container means so that the powder flows over the fiber as the fiber passes through the container means.
Dependencies are inferred from the claim text.