Astenjohnson, Inc.

Jwi Ltd.

Richard E Pitt

Vaughn Wildfong

Roy Van Essen

Karl Lemme

John G Buchanan

David T Smith

Douglas R McPherson

Mark Landry

Victor E Hansen

Thomas Helbig

Michael McMahon

Werner Buchmann

Michael Mcmahon

Douglas R Mcpherson

James D White

A process, and an apparatus, for improving sheet properties in the initial impingement zone of a paper making machine including a forming section, a forming fabric moving in the machine direction and a head box having a head box slice which delivers a stock jet onto the moving forming fabric. The scale and intensity of agitation within the stock is adjusted by adjusting some of the support elements beneath the forming fabric adjacent the head box slice so that they either contact, or do not contact, the machine side surface of the forming fabric and observing the effect, if any, that the adjustment has on the quality of the sheet product being made on the paper making machine. This technique is of use in a papermaking machine forming section having a single open surface forming fabric, in the initial open surface section of a so-called hybrid gap former having two superposed forming fabrics, and in the forming section of a two fabric papermaking machine.

Adjustable activity drainage box

A fabric support element for a papermaking machine has improved fluid drainage means, comprising openings which can include flow-through vents. The element can comprise an impingement shoe for a forming section of a papermaking machine. The opening can be defined by a plurality of laminar segments, at least some of which define a paper side surface of the element, and which segments can be spaced apart by additional laminar segments or other spacing means. Laminar segments for use in the element, a method of constructing the element, and a papermaking machine, or a forming section thereof, including the element are also provided.

Fabric support element for a papermaking machine

A twin fabric gap former forming section for paper making machine is described in which: the pitch of the fabric support elements d decreases progressively in the machine direction; the level of vacuum applied to the forming fabrics through the dewatering boxes increases in the machine direction; the two forming fabrics together with the stock sandwiched between them traverse at least four separate and distinct vacuum zones within the forming section as they proceed in the machine direction; the level of vacuum applied to the last of the at least four separate and distinct vacuum zones is higher than the level of vacuum applied to the first of the separate and distinct vacuum zones; the level of vacuum applied to the at least four separate and distinct vacuum zones follows a preselected profile; and the dewatering boxes carrying the fabric support elements are arranged so that the fabric support elements are located in an alternating sequence on the machine sides of both of the forming fabrics.

Gap type forming section for a two fabric paper making machine

A twin fabric hybrid forming section for paper making machine is described in which: the pitch of the fabric support elements decreases progressively in the machine direction; the level of vacuum applied to the forming fabrics through the dewatering boxes increases in the machine direction; the two forming fabrics together with the stock sandwiched between them traverse at least four separate and distinct vacuum zones within the forming section as they proceed in the machine direction; the level of vacuum applied to the last of the at least four separate and distinct vacuum zones is higher than the level of vacuum applied to the first of the separate and distinct vacuum zones; the level of vacuum applied to the at least four separate and distinct vacuum zones follows a preselected profile; and the dewatering boxes carrying the fabric support elements are arranged so that the fabric support elements are located in an alternating sequence on the machine sides of both of the forming fabrics.

Hybrid type forming section for a paper making machine

A fabric support element for a papermaking machine has improved fluid drainage means, comprising openings which can include flow-through vents. The element can comprise an impingement shoe for a forming section of a papermaking machine. The openings can be defined by a plurality of laminar segments, at least some of which define a paper side surface of the element, and which segments can be spaced apart by additional laminar segments or other spacing means. Laminar segments for use in the element, a method of constructing the element, and a papermaking machine, or a forming section thereof, including the element are also provided.

A process, and an apparatus, for improving sheet properties in a twin fabric paper making machine forming section whereby pressure pulse generation in the stock can be controlled. The pressure pulses are controlled by mounting a vacuum assisted skimmer blade () supported by an adjustable resilient support means () so that its height can be altered, and so that it can respond to transient changes in the stock layer thickness. The resilient and adjustable support means () itself is supported by a vacuum drainage box (), which serves to capture at least the major proportion of the fluid skimmed of by the skimmer blade (). This apparatus the position of the skimmer blade () to be altered in two ways without stopping the paper making machine. The skimmer blade () can be located either so that it is out of contact with the forming fabric (), or so that it can be in contact with the forming fabric. By adjusting the resilient adjustable mounting, the amount of pressure exerted by the skimmer blade () onto the forming fabric surface is controllable, thus controlling the pressure pulses generated by the skimmer blade. The orientation of the skimmer blade can also be controlled, so that rather than the blade surface being substantially parallel to the machine side surface of the forming fabric, it can be angled somewhat with either its leading or its trailing edge pressed into the fabric.

Vacuum box with skimmer blade

An adjustable resilient blade support for use in the forming section of a papermaking machine. The blade support is adjustable, both to allow the attached blade to be moved from a position where it is out of contact to a position where it is pressed into contact with the adjacent forming fabric, and to permit adjustment of the blade orientation relative to the surface of the forming fabric. The blade support is also resilient, and thus allows the blade to respond to transient localized changes in the path of the forming fabric with which it is in contact. The adjustable resilient blade support of this invention is thus of use in an open surface forming section, and also is of use in forming sections in which two forming fabrics are used.

Adjustable resilient blade support

A forming section for a two-fabric paper machine using at least one formation blade having a shallow cavity in its top surface. The cavity is placed and dimensioned to withdraw fluid continuously from the stock, and to propel it back through the fabric and the incipient paper web into the stock so as to cause a controlled level of localized turbulence which serves to improve formation without causing excessive drainage or fines loss. The formation blade shape, in conjunction with the forming fabric tension, is configured to provide a hydraulic seal between the fabric and the stock, so that all of the withdrawn fluid is returned to the stock.

Formation in a two fabric paper machine

A paper making machine forming board is described wherein the rate of drainage of the stock through the forming fabric is curtailed and controlled by applying a low positive air pressure (above ambient atmospheric) to the machine side of the forming fabric. Additionally, a controlled level of agitation is induced in the stock on the forming board, providing better initial paper formation.

Pressurized forming board

A method and apparatus are disclosed whereby the rate of drainage of the stock on a Fourdrinier paper making machine can be controlled for the full length of an open surface forming section. A continuous sealed drainage box is used from adjacent the head box slice to the end of the forming section, within which the air pressure can be controlled. In the area adjacent the head box slice drainage is hindered by the use of a positive (above ambient atmospheric) pressure, while further along the forming section the pressure is decreased to a negative value (below ambient atmospheric). Improved paper formation and first pass retention are obtained.

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Almonte, Canada

Richard E Pitt