Process and apparatus for the formation of fiber felts

Claim 2

A process for improving the distribution of fibers in a felt formed by blowing a gaseous current carrying fibers onto a perforated conveyor which retains said fibers while allowing said gas to pass therethrough, said process comprising: directing said current to sweep over the width of said conveyor in an oscillating movement, and automatically regulating during operation the frequency, amplitude and median direction of said sweep and the speed of said conveyor according to measurements taken of the mass of fibers per unit surface area of the width of said formed felt, said regulation being calculated to minimize deviations in the value of said mass across the width of said felt.

Claim 3

The process of claim 1, wherein the mass of fibers per unit surface area of the felt is measured by radiation absorption of the felt.

Claim 4

Apparatus for the formation of a fiber felt of improved distribution, comprising: means for producing a gaseous current carrying fibers, a receiving container receiving said gaseous current, said container comprising as the floor thereof a gas permeable conveyor retaining said fibers, means for causing said gaseous current to sweep over the width of said conveyor in an oscillating motion, comprising a rotatable guide duct, the movement of which may be modified as to frequency, amplitude and median direction by modification means, and, means for regulating said modification further comprising means for measuring the mass of fibers per unit surface area of the formed belt, means for comparing the measurement so taken with predetermined values, and a means for producing signals to said modification means directing the alteration of said oscillating motion, said signals being provided such that said frequency, amplitude and median direction may be automatically regulated during operation of said apparatus.

Claim 5

Apparatus for the formation of a fiber felt of improved distribution, comprising: means for producing a gaseous current carrying fibers, a receiving container receiving said gaseous current, said container comprising as the floor thereof a gas permeable conveyor retaining said fibers, means for causing said gaseous current to sweep over the width of said conveyor in an oscillating motion, comprising a rotatable guide duct, the movement of which may be modified as to frequency, amplitude and median direction by modification means, and, means for regulating said modification further comprising means for measuring the mass of fibers per unit surface area of the formed belt, means for comparing the measurement so taken with predetermined values, and a means for producing signals to said modification means directing the alteration of said oscillating motion, said signals being provided such that said frequency, amplitude and median direction may be automatically regulated during operation of said apparatus.

Claim 6

The apparatus of claim 3, said means for producing a gaseous current comprising a centrifuge having a plurality of orifices from which are projected fiber filaments, and means for producing an annular gas current which gas current flows along the periphery of said centrifuge, and wherein said guide duct is of circular cross-section and is situated proximally to said centrifuge.

Claim 7

The apparatus of claim 3, wherein said modification means comprises a double action hydraulic jack connected to said guide duct, and a proportional distributor regulating liquid applied to said jack.

Claim 8

The apparatus of claim 3, wherein said means for measuring the mass of fibers per unit surface area comprises a means for measuring the absorption of radiation by the felt.

Claim 9

The apparatus of claim 6, wherein said measurement means comprises a source of x-rays directed through said felt and a means for determining the amount of x-rays absorbed by said felt, said measurement means being displaceable in the direction of the width of the felt.

Claim 10

The apparatus of claim 5, wherein said hydraulic jack comprises an excursion rod, and said measurement means produces a signal to a regulating circuit which controls the amplitude and mean position of the movement of said excursion rod.

Claim 11

The apparatus of claim 7, further comprising a regulating circuit which controls the speed of the conveyor and frequency of the oscillating movement of the guide duct in response to signals received from said measurement means.

Claim 12

The apparatus of claim 3, comprising a plurality of said means for producing a gasesous current carrying fibers.