US3428521A - Adjustable deckle for the suction flat box of a paper-making machine - Google Patents

Description

Sheet of 3 G. A. ROY E L ADJUSTABLE DECKLE FOR THE SUCTION FLAT BOX OF A PAPER-MAKING MACHINE Feb. 18. 1969 Filed July 14, 1965 Andra er fi I | l l I Y l I II Feb. 18, 1969 oy. ET AL 3,428,521 ADJUSTABLE DECKLE FOR THE SUCTION FLAT BOX 4 or A PAPER-MAKING MACHINE Filed July 14, 1965 Sheet g of 2 I I I Andre" Y ATTORNt'YS United States Patent 1 Claim The instant invention relates to a paper-making machine, called a Fourdrinier machine, and more specifically to an improvement in a suction box over which the papermaking web or screen is laid. I

As is known, these suction boxes are elongated casings, generally rectangular in cross-section, and extending completely across and beneath the paper-making table over which the screen or web moves. The top or cover of the casing acts as the support for the web or screen and has a plurality of openings therethrough arranged fully transversely of the table and in a width substantially the same as the desired width of the paper sheet to be made. As its name implies, the suction boxes draw the water out of the layer of pulp lying over the web to gradually increase its consistency into a dense sheet which is subsequently completely dried out over a series of drying rolls. These suction boxes are normally provided, at either end thereof, with a piston extending longitudinally of the suction box (that is across the pulp sheet) to serve to block ofi. some of the suction openings along the sheet edges to thus shorten the resulting sheet, whenever required. In other words, it may be desired to have narrower sheets and for that purpose, pistons such as those are provided which will cut off a portion of the end edge openings from the suction box chamber to thus narrow the sheet.

Now, these pistons span the full width of the suction boxes, as aforesaid, and are supported by a wall standing intermediate between the top and bottom walls of the suction box. It consequently happens that several of the suction openings forward-1y of the piston but over the supporting wall do not open directly into the suction chamber but rather in the piston chamber wherein the suction is in the area which is behind the intermediate wall. The result of this arrangement of the prior art is that the edges of the pulp sheet do not dehydrate as rapidly as the center thereof and the sheet of paper formed often breaks at the edges thereof, is difiicult to draw on the first press roll and, at best, results in a sheet having a substantially smooth and flat center portion but undefined wavy and crimped edges. This difi'iculty is minimized by reducing the speed of the Fourdrinier screen or web which of course results in a reduced production.

The slowing up of the screen or web will however not prevent the formation of wrinkles or crimps but render the sheet more apt to be drawn onto the first press roll. Consequently, there is a waste of production by the slowing down of the Fourdrinier table and there is also a waste of production because of the waste in the paper edges.

It is therefore a main object of the invention to overcome the above noted deficiencies in presently existing machines by providing means wherein the complete sheet to be formed will be exposed to the same intensity of vacuum throughout the length of the suction box across the Fourdrinier table.

Another object of the invention lies in the provision of such an improved adjustable deckle for Fourdrinier machines which would not add to the cost of this machine and which is just as simple and safe in operation and maintenance.

3,428,521 Patented Feb. 18, 1969 These objects may be obtained with the improvement of the invention in a suction box for a paper-making machine, the improved combination comprising a hollow casing having a wall provided with a series of apertures therethrough and defining a vacuum space with which the apertures communicate; a suction opening leading into said vacuum space but unobstructively of the apertures; means defining a chamber out of contact with the vacuum space and located also unobstructively of the apertures in relation to the suction opening; the said means defining a chamber including expansible wall means movable to cause apertures adjacent thereto to open into said chamber out of contact with the vacuum space.

A better understanding of the invention will be afforded by the description that follows of a preferred embodiment of the invention having reference to the appended drawings wherein:

FIG. 1 is a vertical cross-sectional view of part of a suction box incorporating the improvement of the invention;

FIG. 2 is a horizontal cross-sectional view of the embodiment of FIG. 1;

FIG. 3 is a perspective view, partly cut away to show the internal structure, of part of a suction box with the improvement of the invention and inthe area of the deckle or piston.

The adjustable deckle of the invention is formed of the usual elongated hollow casing 1, generally rectangular in cross-section and having a bottom wall 3, spaced parallel side walls 5, a covering top wall 7 and a pair of end walls 9 one of which is shown in FIGS. 1 and 2.

Top wall 7 has a series of suction openings 11 the first ones of which are spaced from end walls 9 and correspond to the longitudinal edges of the sheet of paper.

A web or screen 13 is made to travel over cover wall 7 and is intended to receive a thin layer of paper pulp 15 from which water is drawn out as it travels over suction cover wall 7.

A solid supporting wall 17 extends across casing 1, intermediate top and bottom walls 3 and 7, a length equal to the distance of the first apertures 11 from the corresponding end wall 9, as illusrated in FIG. 1. An expansible wall means 19, to be described more fully later, is mounted for displacement over solid supporting Wall 17. A chamber is thus formed by expansible wall means 19, solid supporting wall 17 and the corresponding parts of cover wall 7 and side walls 5; this chamber 21 being thus out of contact with vacuum space 23.

A suction duct 25 extending through end wall 9 and beneath solid supporting wall 17 defines a suction opening 27 engaging into the vacuum space 23.

It will be immediately apparent from the above description that all suction openings 11 are exposed to the vacuum in vacuum space 23 to the same extent. In prior art devices, the solid supporting wall 17 extended much further into vacuum space 23, beneath a series of suction openings 11 thus forcing the suction openings exposed to the solid wall to travel in an arcuate path around the extended solid walls and decreasing the efiiciency or strength of the vacuum for these openings exposed to the solid supporting wall. It will be noted in FIG. 1 that the path of fluid travel from all openings 11 is unobstructed, nothing standing in the path between the first openings 11, nearest end wall 9, and suction opening 27.

The above-mentioned expansible wall means 19 is 'formed of a radially expansible piston 29' mounted on a solid plate 31 slidable on the said solid supporting wall 17. Plate 31, as it moves leftward or away from end wall 9 is supported, laterally thereof, by two narrow ledges 33 (see FIGS. 2 and 3). Stilfening strut 35 may be provided transversely across casing 1 if deemed necessary.

Leftward displacement of piston 29 is limited by the provision of stop members 37 projecting from side walls 5 into the Vacuum space 23.

The radially deformable piston 29 is formed of a pair of parallel fiat discs 39 having chamfered facing edges at the periphery thereof defining, therebetween, an angular recess into which is received a peripheral gasket 41 ha ing a generally triangular or trapezoidal shape in crosssection with a flat surface adapted to abut the side and top walls of chamber 21 and the top surface of plate 31.

The inner one of discs 39 (nearest end wall 9) is threaded, centrally thereof, on the threaded end of a rod 43 while the other disc 39 (furthest from end wall 9) is freely mounted thereover. A turret nut 45 is screwed at the end of threaded rod 43 and rigidly secured thereto so as to rotate therewith. The inner surface of turret nut 45 abuts the outer face of disc 39 furthest from end wall 9.

Rod 43 extends through and is centrally secured to a first ring 47 and is also secured to a second ring 49, spaced away from the first ring 47. The portion of rod 43 between rings 47 and 49 sits in a stirrup member or yoke 51 in the manner of a bearing, which stirrup 51 is an upstanding part of plate 31. An actuating rod 53 has one end thereof removably mounted on second ring 49 in any known manner as by a bayonet connection.

Consequently, threaded rod 43 is mounted over plate 31 for rotation but longitudinal displacement thereof is prevented.

With the above arrangement, it will be understood that rotation of removable actuating rod 53 in one direction will cause closing of the two discs 39 and consequently upward expansion of gasket 41 thus tightly connecting piston 29 to the walls of chamber 21. Inversely, rotation of actuating rod 53 in opposite direction will cause spreading of the two discs 39 and loosening of piston 29 from the walls of chamber 21. In that condition, it is possible to move the expansible wall means 9 longitudinally along supporting wall 17 and supporting ledges 33. As shown in FIG. 1, it becomes possible to cut off openings 11 of the first and second rows in relation to end wall 9 from suction chamber 23, openings 11 of the first row actually leading into chamber 21 when piston 29 abuts the stop members 37.

It should particularly be noted that regardless of the positioning of expansible wall means 19, all remaining openings 11 will be in direct contact with suction opening 27 at all times.

Although a specific embodiment has just been described, it will be understood that various modifications may be made thereto without departing from the spirit of the invention as set forth in the appended claim.

We claim:

1. An adjustable deckle for suction boxes of papermaking machines, comprising:

(a) a sub-atmospheric pressure chamber provided with a series of apertures therethrough across the width of said chamber;

(b) a suction duct extending adjacent said chamber and across the width of said chamber;

(c) a solid supporting wall between said chamber and the suction duct having a series of openings therein connecting the said duct to the said chamber;

(d) movable piston means at one end of said chamber for increasing the width of the said chamber and exposing additional apertures to said chamber, the said additional apertures being located at one end of the series of apertures;

(e) a slot in said supporting wall facing said additional apertures, whereby the suction produced between the said additional apertures and the said slot is substantially perpendicular to the supporting wall.

References Cited UNITED STATES PATENTS 10/1929 Carroll 162-366 2/1946 Clem .162366 US. Cl. X.R. 162-363

Claims (1)

1. AN ADJUSTABLE DECKLE FOR SUCTION BOXES OF PAPERMAKING MACHINES, COMPRISING: (A) A SUB-ATMOSPHERIC PRESSURE CHAMBER PROVIDED WITH A SERIES OF APERTURES THERETHROUGH ACROSS THE WIDTH OF SAID CHAMBER; (B) A SUCTION DUCT EXTENDING ADJACENT SAID CHAMBER AND ACROSS THE WIDTH OF SAID CHAMBER;

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