Abstract: A valve for a vacuum drainage system includes a valve body having an interior chamber operatively connectable to a suction device and through an outlet to a vacuum source. A movable member having an aperture is secured within the chamber and movable through points between closed and open positions to adjust the open area of the aperture and the fluid flow through the outlet. The aperture is configured such that during adjustment to increase the effective operational area of the aperture, a rate of change of the effective operational area increases non-linearly in relation to a linear increase in the distance of travel, while providing advantageous and more controllable linear adjustment of the applied vacuum. The aperture can have a trilateral shape including at least one curved side, or comprise a plurality of sub-apertures, and the movable member can comprise a rotary sleeve.

Abstract: A valve for a vacuum drainage system includes a valve body having an interior chamber operatively connectable to a suction device and through an outlet to a vacuum source. A movable member having an aperture is secured within the chamber and movable through points between closed and open positions to adjust the open area of the aperture and the fluid flow through the outlet. The aperture is configured such that during adjustment to increase the effective operational area of the aperture, a rate of change of the effective operational area increases non-linearly in relation to a linear increase in the distance of travel, while providing advantageous and more controllable linear adjustment of the applied vacuum. The aperture can have a trilateral shape including at least one curved side, or comprise a plurality of sub-apertures, and the movable member can comprise a rotary sleeve.

Abstract: Segments, typically ceramic, for use in dewatering blades for papermaking and similar machines comprise lower surfaces to each of which at least one interlock member is bonded. The segments are installed by inserting the interlock members into a channel in an intermediate sub-assembly or base member. The members are securely attached within the channel by a suitable adhesive, or clip means to engage the interlock members, with the optional addition of an adhesive. The segments and dewatering blades, and a method of manufacture, allows for the segments to be made as flat units, without unnecessary angular surfaces, simplifies their attachment to the base, and reduces the occurrence of stress cracking or other damage to the segments. A single segment can be used in various dewatering blade types and in more than one orientation in dewatering blades, reducing manufacturing costs by unitizing construction.

Abstract: Dewatering blades for use in papermaking machines are assembled from two or more pre-finished sub-assemblies which are in turn mounted on a base member. Each sub-assembly comprises a holder, configured to receive a plurality of segments, constructed of a wear-resistant material such as ceramic, which will be located so as to be in sliding contact with the underside of a papermaking fabric. The holders are adapted for insertion into and retention in the base member, which is subsequently affixed to the papermaking machine by known means. The construction of the sub-assemblies allows for the manufacture of a full length blade from a plurality of sub-assemblies, which dramatically reduces manufacturing cost while providing for more rapid deliveries and simplified repair of damaged blades.

Abstract: Segments, typically ceramic, for use in dewatering blades for papermaking and similar machines comprise lower surfaces to each of which at least one interlock member is bonded. The segments are installed by inserting the interlock members into a channel in an intermediate sub-assembly or base member. The members are securely attached within the channel by a suitable adhesive, or clip means to engage the interlock members, with the optional addition of an adhesive. The segments and dewatering blades, and a method of manufacture, allows for the segments to be made as flat units, without unnecessary angular surfaces, simplifies their attachment to the base, and reduces the occurrence of stress cracking or other damage to the segments. A single segment can be used in various dewatering blade types and in more than one orientation in dewatering blades, reducing manufacturing costs by unitizing construction.

Abstract: A headbox including a stock dilution profiling arrangement and associated stock delivery systems are provided, which together deliver to the forming section of a papermaking machine a uniform stock flow with more consistent basis weight and fiber orientation profiles than has previously been possible. These improvements in basis weight uniformity and fiber orientation profile provide benefits in paper sheet formation and related paper properties.

Abstract: A cover for a vacuum dewatering box that is formed from a plurality of blocks, each including a wear surface, is provided. At least some of the blocks are spaced apart to form at least one generally longitudinally oriented slot through the cover, with a shape and size of the at least one slot being determined by at least one of a location of and a shape of the blocks. Preferably, the at least one slot is formed with a zig-zag or herringbone pattern, and can be used on a suction box or Uhle box on a papermaking machine. A vacuum dewatering box having this type of cover is also provided.

Abstract: Dewatering blades for use in papermaking machines are assembled from two or more pre-finished sub-assemblies which are in turn mounted on a base member. Each sub-assembly comprises a holder, configured to receive a plurality of segments, constructed of a wear-resistant material such as ceramic, which will be located so as to be in sliding contact with the underside of a papermaking fabric. The holders are adapted for insertion into and retention in the base member, which is subsequently affixed to the papermaking machine by known means. The construction of the sub-assemblies allows for the manufacture of a full length blade from a plurality of sub-assemblies, which dramatically reduces manufacturing cost while providing for more rapid deliveries and simplified repair of damaged blades.

Abstract: A flexible mounting for use in the forming section of a twin forming fabric paper making machine consisting essentially of a base member supported by the paper making machine structure to which is attached a flexible C-shaped beam. The C-shaped beam has one edge attached to the base member, and a fabric contacting blade attachment means at the other edge. A pressurized loading tube is located within the C-shaped beam between the base member and the second edge of the C-shaped beam. When the pressurized loading tube is loaded, the C-shaped beam flexes thus allowing the blade to move initially into contact with a forming fabric. As the pressurized tube is further loaded, the contact face of the blade is moved into further engagement with the forming fabric. In a preferred construction, the wrap angle of the fabrics at or about the blade leading edge can be minimized. The mounting thus can diminish wear of the fabric as it passes over the blade.

Abstract: A flexible mounting for use in the forming section of a twin forming fabric paper making machine consisting essentially of a base member supported by the paper making machine structure to which is attached a flexible C-shaped beam. The C-shaped beam has one edge attached to the base member, and a fabric contacting blade attachment means at the other edge. A pressurized loading tube is located within the C-shaped beam between the base member and the second edge of the C-shaped beam. When the pressurized loading tube is loaded, the C-shaped beam flexes thus allowing the blade to move initially into contact with a forming fabric. As the pressurized tube is further loaded, the contact face of the blade is moved into further engagement with the forming fabric. In a preferred construction, the wrap angle of the fabrics at or about the blade leading edge can be minimized. The mounting thus can diminish wear of the fabric as it passes over the blade.

Abstract: A method and apparatus for generating turbulence in stock to deflocculate the stock in an open surface forming section of a paper making machine comprises a dewatering box providing vacuum assisted drainage and which has a set of dewatering elements that impart turbulence into relatively thick stock layers carried at machine operating speeds of equal up to about 400 m/min, for the production of paper products having a basis weight generally in excess of about 160 gsm. Each set of elements includes a lead-in element, at least one intermediate element, and a trailing element. The path of the forming fabric is deflected downwardly as it passes over the intermediate elements, which are inclined at an angle of from about 0.25.degree. to about 10.degree. from a plane defined by forming fabric supporting surfaces on the lead-in and riser elements. This vertical movement initiates turbulence and agitation in the stock, which acts both to deflocculate the stock and to diminish the possibility of sheet sealing.

Abstract: Clip type fasteners for attaching paper machine fabric contacting elements to their supporting structures. The fasteners are provided typically with two tight tolerance slots, which are press-fits onto the elements and the support structure. The fasteners allow for simple removal, replacement, and respacing of the elements.

Abstract: 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.

Abstract: 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.