US3288668A - Apparatus for regulating the flow of stock onto a forming wire in fourdrinier type papermaking machines and the like - Google Patents

Description

1966 E. o. MUSTONEN APPARATUS FOR REGULATING THE FLOW OF STOCK ONTO A FORMING WIRE IN FOURDRINIER TYPE PAPERMAKING MACHINES AND THE LIKE Filed Nov 18 1963 wire.

United States Patent This invention relates to an improved apparatus for regulating the stock stream of pulp, cellulose or the like that flows from the head box onto the forming wire in Fourdrinier type paper making machines, cellulose collectors or the like.

The stock stream flowing onto the forming wire is regulated in order to adjust the thickness of the stock stream and to make the stream flow parallel with the forming It must further be possible to direct the stock stream against the forming wire at a desired angle and to have it contact the forming wire at a desired point with respect to the breast roll of the paper machine.

These requirements are carried out in many different way-s. In certain conventional types of head boxes the front wall of the stock head box is movable, while the apron of the sluice outlet and the breast roll are fixed. The thickness of the stock stream is regulated by raising or lowering the front wall of the head box. The stock stream is led out parallel with the forming wire. The desired angle of the stream relative the forming wire is obtained by rotating the front wall around an axis located near a packing unit between said axis and the ceiling of the head box. The stock stream is made to strike the forming wire at the desired point by moving the whole stock head box on its base rails or by changing the lower lip plate to a new one.

There is also known another type of head box in which the turning axis of the front wall is arranged near the perforated roll within the head bar in such a way that when adjusting the gap between the lips, the distance between the front wall and the flow roll practically remains unchanged.

In stock head boxes of the above described types the construction of the front wall, however, is such that the hydraulic force of the stock acting upon the front wall will result in an unbalanced force relative to the turning axis of the wall.

This is a considerable drawback requiring a great turning force which is greatly reduced by the arrangement according to the invention. The invention is directed to such a head box in which the stock flow thickness is regulated by raising or lowering the front wall and in which the direction of the flow is adjusted by pivoting the front wall around an axis close to the perforated flow roll so as to maintain the gap between said roll and the front wall practically unchanged. The device is characterized in that the above mentioned hydraulic forces acting upon the front wall are balanced relative to the turning axis by such a design of the front wall so that the resultant of the hydraulic forces of the stock is disposed in the horizontal plane through the center of gravity of the wall, while the pivot axis of the front wall is also located in said plane.

An embodiment of the invention will now be described with reference to the sole figure of the accompanying drawing. In the drawing, in which the adjusting movements are schematically shown, reference 1 designates the movable front wall. By raising or lowering the front wall the thickness of the stock stream will be adjusted while passing through the gap between the outlet lips 2 and 3. For shifting the edge of the upper lip 2 of the 3,288,668 Patented Nov. 29, 1966 sluice relative to the edge of the fixed lower lip 3 the front wall is pivotably mounted about a turning axis 4. Within the head box there are two operated rolls 5 and 5'. The axis 4 is located close to the upper perforated roll 5', so that the gap between this roll and the front wall 1 does not change to any appreciable extent when the front wall is turned. The axis 4 is preferably located at approximately the same level as the axis of the upper perforated roll 5 and at approximately the same level as the center of gravity of the front wall and close to the inside surface of the front wall. It is a feature according to the invention to locate said axis 4 in a horizontal plane through the resultant of the hydraulic forces of the stock acting upon the front wall and through the center of gravity of the front wall.

Besides the fact that the gap between the roll 5' and the front wall remains unchanged, the above arrangement of the pivot axis has further advantages. Thus, if the front wall is turned in either direction, the stock quantities which are above and below the horizontal plane through axis 4 have substantially equal effects on the front wall, one part of the stock applying a turning moment in one direction and the other part in the opposite direction so that the two effects will annul another. This is not the case with the earlier known devices where the front wall is turned around an axis in its upper part which causes an unbalanced turning moment due to the hydraulic forces acting upon the wall.

The point where the stock stream falls onto the forming wire 6 relative to the breast roll 7 is adjusted by shifting the breast roll horizontally to the desired location relative to the outflow gap 8.

The apparatus also contemplates adjustment of the overflow baffle while the front wall is being turned. The breasting edge for regulation of the overflow is performed by the dam baffle plate 9, the lower edge of which is fixed to the front wall by hinges 10 and its upper edge at several points to pendent levers 11 fixed to the ceiling so that the upper edge of the baffle plate is kept substantially horizontal while the front wall is being turned.

The above described embodiment is, of course, only to be understood as an illustration of the inventive idea of the invention, and various modifications may thus be made as to the details and construction within the scope and limits of the following claims.

What is claimed is:

1. Apparatus in a stock head box of a Fourdrinier type machine for regulating the stock stream from between two perforated flow equalizing rolls within a stock head box onto a forming wire between two opposite lips in an outlet gap of the head box, said apparatus comprising a vertically movable front wall for the stock head box, said front wall being pivotable around an axis which is located close to the upper of the two perforated flow equalizing rolls within the stack head box near the front wall, said pivot axis of the front wall being disposed in a plane through the resultant of the hydraulic forces of the stock acting on the front wall and through the center line of said upper perforated flow equalizing roll and also through the center of gravity of the front wall.

2. Apparatus as claimed in claim 1 including a baffle plate having a lower edge hingeably attached to the front wall and lever means supporting the upper edge of the' baflle plate from the head box so that the upper edge of the baffle plate is kept substantially horizontal while the front wall is being turned.

3. In apparatus for regulating the stream of stock from a head box onto a forming wire in which the head box has a turnable front wall and a baffle plate mounted therein which is maintained horizontal while the front wall is being turned, an improvement comprising means adjacent said head box defining said front wall thereof, said means 3 4- being mounted for pivotable movement about an axis, References Cited by the Examiner said head box having a pair of ertically spaced flow UNITED STATES PATENTS equalizlng rolls mounted therein, -sa1d means defining w1th said head box an outflow gap for the flow of stock from 2349,5315 6/1956 Stewart 162338 the head box, said axis being disposed at the level of the 5 2,881,674 4/1959 Johnson et 162216 center of the upper of the rolls and in a plane passing 2199 3,538 7/1961 Mustonen 162 '347 through the resultant of the hydraulic forces of the stock acting on said means and the center of gravity of said D ONALL SYLVESTER Prmmry Exammer' means. I. H. NEWSOME, Assistant Examiner.

Claims (1)

1. APPARATUS IN A STOCK HEAD BOX OF A FOURDRINIER TYPE MACHINE FOR REGULATING THE STOCK STREAM FROM BETWEEN TWO PERFORATED FLOW EQUALIZING ROLLS WITHIN A STOCK HEAD BOX ONTO A FORMING WIRE BETWEEN TWO OPPOSITE LIPS IN AN OUTLET GAP OF THE HEAD BOX, SAID APPARATUS COMPRISING A VERTICALLY MOVABLE FRONT WALL FOR THE STOCK HEAD BOX, SAID FRONT WALL BEING PIVOTABLE AROUND AN AXIS WHICH IS LOCATED CLOSE TO THE UPPER OF THE TWO PERFORATED FLOW EQUALIZING ROLLS WITHIN THE STACK HEAD BOX NEAR THE FRONT WALL, SAID PIVOT AXIS OF THE FRONT WALL BEING DISPOSED IN A PLANE THROUGH THE RESULTANT OF THE HYDRAULIC FORCES OF THE STOCK ACTING ON THE FRONT WALL AND THROUGH THE CENTER LINE OF SAID UPPER PERFORATED FLOW EQUALIZING ROLL AND ALSO THROUGH THE CENTER OF GRAVITY OF THE FRONT WALL.

Images