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The characteristic profile of a paper web is adjusted on the fourdrinier by means of a number of fluid spray stations positioned across the papermachine. Each spray station is provided with two or more fan spray nozzles of different flow capacity oriented to impact the pond with fluid along a common

The characteristic profile of a paper web is adjusted on the fourdrinier by means of a number of fluid spray stations positioned across the papermachine. Each spray station is provided with two or more fan spray nozzles of different flow capacity oriented to impact the pond with fluid along a common line. Flow to each nozzle is binary controlled with respective binary command, full flow valves. By discrete manipulation of valve selection, total flow rate to the web may be adjusted without flow throttling and consequent impact velocity variations.

대표청구항 ▼

An apparatus for leveling the cross-directional distribution of a fiber or water paper stock constituent within a dilute aqueous slurry deposited continuously upon a machine-direction traveling foraminous screen as the first of several water removal steps in a paper web forming sequence, said consti

An apparatus for leveling the cross-directional distribution of a fiber or water paper stock constituent within a dilute aqueous slurry deposited continuously upon a machine-direction traveling foraminous screen as the first of several water removal steps in a paper web forming sequence, said constituent leveling apparatus comprising: A. A papermachine headbox containing said dilute aqueous slurry of stock and having a cross-directionally elongated slice opening adjacent said traveling screen for depositing a fluidized pond of said stock slurry thereon; B. Cooperative sensing means and reporting means for detecting the cross-directional concentration profile of a single stock constituent within a continuously forming paper web consolidated from said stock slurry and reporting the magnitude of such concentrations relative to the cross-directional location thereof; C. A fluid supply manifold; D. A plurality of fluid spray stations distributed cross-directionally across said traveling screen and connected to said manifold or fluid supply therefrom; each of said spray stations comprising a plurality of fixed orifice fan spray nozzles for providing different incremental station flow rates, each nozzle of a respective station sized to discharge a respective flow rate of fluid at substantially the same velocity and spray width upon impact with said stock as such other nozzles in said respective station, all of said respective station nozzles being positioned to strike with a fluid spray issuing therefrom the same increment of a line extended across the plane of said web pond within a fiber mobile zone located between a line of stock landing upon said screen and a dry line formed thereon; E. A binary command, full flow, remote controlled valve respective to each nozzle disposed in a respective fluid conduit between each nozzle and said supply manifold; and F. Command station means for selectively emitting binary command signals to each of said controlled valves. A method of leveling the cross-directional profile of a paper stock constituent of either fiber or water subsequent to landing on a traveling foraminous screen, said method comprising the steps of: A. Providing a plurality of fluid spray sources distributed substantially equidistantly across said screen to issue a cross-directionally elongated fan spray pattern of fluid impacting a pond of said stock on said screen along a cross-directional line within a fiber mobile zone of said pond between a line whereat said stock lands on said screen and a dry line formed in said stock on said screen; B. Sensing the cross-directional location of an undesirable concentration of said constituent within a consolidated web emerging continuously from said screen; C. Providing a reference flow rate of fluid from one of said sources most proximate of the cross-directional center of said concentration; D. Providing other flow rates of fluid from other of said sources laterally adjacent said one source, said other flow rates being less than said reference flow rate and diminishing in graduated increments relative to the order of location removal of a respective other source from said one source; and E. Maintaining a substantially uniform fluid impact velocity and fan spray width from all of said plurality of said sources having a flow rate.