Fiber collector

A method of collecting fiber from a moving airflow having entrained fibers comprising

• introducing the airflow with its entrained fibers into a primary plenum having a fiber collection zone in a lower portion thereof,
• passing at least three portions of the air flow through three screens downstream of the primary plenum and slanted with respect to the primary plenum so that fiber held by the screens will be gravitationally attracted to the fiber collection zone,
• passing the airflow portions through secondary plenums downstream of each of the screens and through independently closable passages downstream of the secondary plenums without substantially restricting the flow of the portion of air by the passage,
• sensing the pressure upstream of the screens,
• sensing the pressure downstream of the passages, and in response to the sensed pressures indicating an excessive difference between the upstream and downstream pressures characteristic of fiber buildup on the screens,
• closing the passage for one of the secondary plenums and introducing a flow of clean air to the same secondary plenum as a backwash to cause the fibers held by the screen upstream of that secondary plenum to be dropped in to the fiber collection zone,
• after a preset period of time halting the clean air flow to the secondary plenum and opening the passages,
• continuing to backwash secondary plenums in a preset sequence of secondary plenums as long as the pressure difference is excessive and
• halting the backwash sequence if the pressure difference after a backwash is no longer excessive, but resuming the sequence where it was left off when the pressure becomes excessive again.

A fiber collector for collecting fiber from a moving airflow having entrained fibers comprising

• a primary plenum into which the moving airflow with entrained fibers is introduced having a fiber collection zone in a lower portion thereof,
• at least three screens forming a boundary downstream of said primary plenum,
• at least three secondary plenums, one each downstream of one of said screens and each having an independently openable air inlet for a reverse airflow downstream of the screen, and at least three independently closable passages, one each being downstream of one of said secondary plenums,
• a first pressure sensor upstream of said screens,
• a second pressure sensor downstream of said independently closable passages downstream of said screens, an airflow moving means downstream of the screens for moving the air flow, and
• control means receiving pressure sense data from said pressure sensors and closing said independently closeable passage for one of said secondary plenums and opening said independently openable air inlet of the same secondary plenum when the pressure difference between said first and second pressure sensors exceeds a desired value,
• whereby an airflow with entrained fibers may be introduced into said primary plenum, with the airflow passing through said screens and fiber falling into said collection zone or being held by said screens, and
• when one of said screens is so full of held fibers as to inhibit air flow therethrough and thereby increase the pressure difference measured by said first and second sensors, said independently openable air inlet to said secondary plenum downstream of said full screen is openable and said independently closeable passage downstream of said full screen is closeable so that the airflow through said full screen is reversed as a backwash to cause the fibers held by said screen to be dropped in to said fiber collection zone.

A fiber collector for collecting fiber from a moving airflow having entrained fibers comprising

• a primary plenum into which the moving airflow with entrained fibers is introduced having a fiber collection zone in a lower portion thereof,
• at least three screens downstream of said primary plenum and adjacent one another and slanted with respect to said primary plenum so that fiber held by said screens will be gravitationally attracted to said fiber collection zone,
• a secondary plenum downstream of each of said screens and each having an independently openable air inlet, and
• an independently closable set of louvers downstream of each of said secondary plenums, each set of louvers having of area about one half as large as the area of its secondary plenum in a plan perpendicular to the direction of airflow through said secondary plenum,
• a fan downstream of said louvers to pull air through said primary plenum, screens, secondary plenums and sets of louvers,
• a first pressure sensor upstream of said screens,
• a second pressure sensor downstream of said independently closable set of louvers, and
• control means receiving pressure sense data from said pressure sensors and closing said set of louvers for one of said secondary plenums and opening said independently openable air inlet of the same secondary plenum when the pressure difference between said first and second pressure sensors exceeds a desired range,
• whereby an airflow with entrained fibers may be introduced into said primary plenum, with the airflow passing through said screens and fiber falling into said collection zone or being held by said screens, and
• when one of said screens is so full of held fibers as to inhibit air flow therethrough and thereby increase the pressure difference measured by said first and second sensors, said independently openable air inlet to said secondary plenum downstream of said full screen is openable and said independently closeable set of louvers downstream of said full screen is closeable so that the airflow through said full screen is reversed as a backwash to cause the fibers held by said screen to be dropped in to said fiber collection zone, and
• wherein said control means closes said independently openable air inlet and opens said set of louvers after a preset period of time and continues to backwash secondary plenums in a preset sequence of secondary plenums as long as the pressure difference exceeds the preset range and halts the backwash sequence if the pressure difference after a backwash is below the preset range, but resumes the sequence where it left off when the pressure drops below the preset range.