US3377236A - Drainage element - Google Patents

Description

April 1968 A. c. ROECKER 3,377,236

DRAINAGE ELEMENT Filed March 5, 1965 2 Sheets-Sheet 1 INVENTOR. 4L V/A/ C ZOECKEZ ATTORNEYS A. C. ROECKER DRAINAGE ELEMENT April 9, 1968 Filed March 3, 1965 2 Sheets-Sheet T v INVENTOR. 44 w/v C Ease/ 61? bm filly ATTORNEYS ilnited States Patent C) 3,377,236 DRAINAGE ELEMENT Alvin C. Roecker, Beloit, Wis., assignor to Beloit Corporation, Beloit, Wis., a corporation of Wisconsin Filed Mar. 3, 1965, Ser. No. 436,893 9 Claims. (Cl. 162-263) ABSTRACT OF THE DISCLOSURE A dewatering member extending along beneath a travelling Fourdriner wire having a small upwardly curved leading portion ahead of the point of contact with the wire and having a planar trailing portion diverging away from the wire at a small angle.

The present invention relates to improvements in papermaking machines and more particularly to an improved stationary web dewatering element positioned beneath a traveling Fourdrinier wire.

In accordance with the invention a stationary drainage element is located in wire supporting relationship beneath the travelling wire and this drainage element may for purposes of this disclosure be termed a foil. The drainage element or foil may be located in various optimum positions following the breast roll and the location where stock is discharged onto the travelling Wire, but one or more foils is preferably located just following the forming board at locations otherwise occupied by table rolls in many Fourdrinier machines. Stationary drainage elements of these types have been used in the art but disadvantages have been encountered which have been discovered to be inherent in the structures heretofore used following the teachings of the art. Considerable frictional drag is encountered bettween the upper surface of the foil and the lower surface of the wire increasing horsepower requirements over theat normally required by table rolls which have surfaces travelling with the wire. Also in foil structures heretofore available uneven effects on the wire and the web formed thereon have occurred in some respects due to the collection of fibers on the leading edges of the foils resulting in streaking or worming of the web and imperfections across the paper sheet formed therefrom. These imperfections may be caused from various effects on the web and wire from the foil not all of which may be completely understood but it has been found that a foil of the present structure avoids the disadvantages previously encountered and provides a superior paper web.

It is accordingly an object of the present invention to provide an improved paper web dewatering foil which reduces the frictional drag between the foil and Fourdrinier wire and noticeably reduces the horsepower consumption required to drive the wire.

It is another object of the invention to provide an improved paper dewatering foil which does not result in a non-uniform dewatering and imperfactions in the paper web and is capable of continuous long run operation without attention or cleaning.

A still further object of the invention is to provide a foil of an improved design which can more easily be manufactured to obtain straight and uniform contact between the foil and wire completely across the machine and wherein the dewaten'ng effect and coaction between the foil and wire and between the foil and water coming off the wire on the ofifrunning side is uniform. I

A still further object of the invention is to provide improved foil structure which has a considerably longer wearing life and which utilizes acoating on the upper surface .of unique construction and of reduced cost as contrasted with coating available.

Other objects, features and advantages will become more apparent with the teachings of the principles of the invention connected with the disclosure of the preferred embodiment thereof in the specification, claims and drawings, in which:

FIGURE 1 is a detailed fragmentary end elevational view, shown in somewhat schematic form, of a foil constructed in accordance with the principles of the present invention;

FIGURE 2 is an end elevational view of a foil and its supporting mechanism; and

FIGURE 3 is a fragmentary sectional view taken substantially along line III'III of FIGURE 2.

On the drawings:

FIGURES 1 and 2 show a foil 10 supported beneath a traveling Fourdrinier wire W. The foil has an upper surface facing the wire and the surface has a trailing planar portion 13 leading from the point of wire engagement 17 to a trailing edge 14.

The surface has a leading surface portion 15 which is arcuate and extends from a leading edge -16 of the foil to said location of wire engagement 17. In theory point 17 will have line engagement with the wire since it is formed at the juncture of arcuate surface 15 and planar surface 13 but actually due to the flexibility of the wire it will wrap slightly at point 17 to provide surface engagement over a small width.

As shown in FIGURES 2 and 3 the foil is supported on pintles 11 ateach end and these are rotatably journalled in sockets 12 in a support frame bracket 30.

The position of the foil is adjusted for operation relative to the wire W so that the trailing portion 13 of the upper surface forms a diverging angle with the wire on the order of 0 to 5 measured when the wire is stationary. A 3 diverging angle has been found satisfactory although adjustment can be made While the machine is operating observing optimum dewatering effect and making adjustments accordingly.

A portion only of the upper surface of the foil is provided with a hard mirror finish coating. The foil is coated over the limited area preferably with a tungsten carbide, a Satellite, titanium carbide or a ceramic crystalline refractory metal oxide such as aluminum oxide polished to a mirror finish. The ceramic material coating will form a thin monolithic surface layer over the foils polished to a mirror finish in the range of 4 to 15 micro inches. The coating has a construction somewhat similar to and may be applied in accordance with the teachings found in the copending application of Charles W. E. Walker entitled, Suction Box Cover, U.S.- Ser. No. 15 0,917, filed Nov. 8, 1961, which is incorporated herein by reference. In accordance with the principles of the invention only a portion of the surface is coated and the surface is coated from the leading edge 16 for an area of between 16% and 40% of the total surface with the coating terminating along a straight line 18. The straight line or trailing edge of the coating is at a uniform distance from the trailing edge 14 of the foil across the machine so that uniform effects on the Water coming through the wire from the web are attained. With the limitation of the total area of foil surface which is coated improved water flow effects have been observed. Also with decreased wear or improved wearing life between the wire and foil surface result. A further advantage is a saving in the amount of coating material required and the time required for coating.

An important feature of the invention is the formation of the leading portion 15 of the surface in an ar'cuate shape. The are is formed with its center C preferably arrangements heretofore coincident with the center C of the pintle 11 supporting the foil. With this arrangement the change in angle of the ofirunning or trailing portion 13 of the surface relative to the wire will not change the relationship between the wire and the upper surface portion 15 at least for a substantial distance in advance of the intermediate wire contact location 17.

The leading edge 16 of the foil is rounded. The formation of the curvature of the leading portion 15 makes it possible to machine an upper foil surface in a manner to obtain substantially complete uniformity completely across the width of the wire. A close gap is maintained between the wire and the surface portion 15 and if the gap is not maintained uniform streaking and running will occur in the web formed on the wire. A preferred gap between the Wire and leading surface 15, with the gap shown at 19, is from 2 to 3 thousandths of an inch measured when the wire is running. The gap is preferably maintained in the range of 0.002 to 0.010 of an inch. When the gap is measured with the stationary wire it is preferably maintained in the range of 0.006 to 0.012 of an inch. It has been found that a significant and unforseen reduction in horsepower requirements for driving the wire occur when an arcuate leading surface is employed as contrasted with providing a sharp leading edge for the foil and having immediate planar surface engagement between the foil and the wire. It has also been found that this results in avoiding worming, streaking and running and it is believed that with the provision of a sharp leading edge small particles of fibers tend to briefly accrue at the sharp leading edge which either are substantially dewatered or which have a different consistency across the wire so that they tend to climb over the sharp edge of the foil beneath the wire or at least effect the dewatering effect of the subsequent upper foil surface. These adverse effects are avoided with the present construction.

The length of the leading arcuate foil surface 15 must be adequate to give the resultant effect and shown in the drawing of the arcuate length extends over 4 of a circle, as indicated by the angle on. An arcuate length of greater than 1 has been found to be necessary.

The arcuate surface is shown formed at a radius R which is in the range of greater than inch and less than inches.

As illustrated in FIGURES 2 and 3 the foil'is rigidly supported at its adjusted angle by mechanism which is the same at both ends of the foil so that only one end may be shown in detail. The foil has an arm 25 projecting axially from it spaced radially from the supporting pintle 11. The arm is carried on a supporting stop bolt 24 which extends upwardly through the arm 25. The arm 25 is provided with fragmentary spherical shaped surfaces 26 and 27 which rest in a lower socket on a bolt 24 and in an upper socket on a washer 28 on the bolt. The bolt is threaded into the frame bracket 30 and is turned upwardly by applying a wrench to a square upper end 31. The adjusted position will be held by locking nuts 29 and 32.

Secured to the pintle end is an indicator pointer 22 which indicates on a dial 23 the actual angle between the upper trailing surface 13 of the foil and the wire W.

Thus, it will be seen that I have provided improved foil structure having an arcuate leading surface portion and a trailing planar portion 13. The structure contains the objectives and advantages set forth in greater detail above and provides an effective improved dewatering member for a papermaking machine.

The drawings and specification present a detailed disclosure of the preferred embodiments of the invention, and it is to be understood that the invention is not limited to the specific forms disclosed, but covers all modifications, changes and alternative constructions and methods falling within the scope of the principles taught by the invention.

I claim as my invention: 1. In a Fourdrinier papermaking machine having a traveling wire,

a stationary dewatering member in association with the the wire and having a dewatering surface, said surface having a leading portion and a nd a trailing portion relative to the direction of wire travel, the trailing portion of said surface being planar and diverging away from the wire at a small angle, the leading portion of said surface being arcuate in shape and leading toward the wire to an engaging portion between said leading and trailing portions providing a space between the wire and said leading portion so that the frictional drag at the foil is reduced to reduce the power required to drive the wire and optimum dewatering of a Web on the wire is obtained. 2. In a Fourdrinier papermaking machine having a traveling wire,

a stationary dewatering member in association with the Wire and having a dewatering surface, said surface having a leading portion and a trailing portion relative to the direction of wire travel, the trailing portion of said surface being planar and diverging away from the wire at a small angle, the leading portion of said surface being arcuate in shape and leading toward the wire to an engaging portion between said leading and trailing portions providing a space between said leading portion and said wire, the arcuate shape of said leading portion having an arc of curvature in the range of greater than 0 inch and not exceeding l0 inches so that frictional drag at the dewatering member is reduced to reduce the power required to drive the wire and optimum dewatering of a Web on the wire is obtained. 3. In a Fourdrinier papermaking machine having a traveling wire,

a stationary dewatering member in association with the wire and having a dewatering surface, said surface having a leading portion and a trailing portion relative to the direction of wire travel, the trailing portion of said surface being planar and diverging away from the wire at a small angle, the leading portion of said surface being arcuate in shape and leading toward the wire to an engaging portion between said leading and trailing portions providing a space between said leading portion and said wire so that the frictional drag at the foil is reduced to reduce the power required to drive the wire and optimum dewatering of a web on the wire is obtained, and a pivotally mounted support for said dewatering member located in spaced relation with respect to said surface at a location substantially coincident with the radial Center of said arcuate leading por tion of the surface so that the attitude of said dewatering member relative to the wire may be changed for changing the angle between the trailing portion and the wire without changing the relationship between the wire and the arc of curvature of said leading portion. 4. In a Fourdrinier papermaking machine having a traveling wire,

a stationary dewatering member in association with the wire and having a dewatering surface, said surface having a leading portion and a trailing portion relative to the direction of Wire travel and having a leading edge at the beginning of said arcuate leading portion, the trailing portion of said surface being planar and diverging away from the wire at a small angle, the leading portion of said surface being areuate in shape and leading toward the wire to an engaging portion between said leading and trailin portions,

the distance between the wire and said surface at said leading edge measured when the wire is running being in the range of 0.02 to 0.010 of an inch so that the frictional drag at the dewatering member is portion between said leading and trailing portions,

edge being spaced from the wire in the range of 0.006 to 0.012 of an inch measured when the wire is stationary,

a mirror finish hard ceramic coating on said surface reduced to reduce the power required to drive the 5 beginning from said leading edge and having a wire and optimum dewatering of a web on the Wire finish in the range of 4 to 15 micro inches extending is obtained. toward the trailing edge covering only a portion of 5. In a Fourdrinier papermaking machine having a the upper surface in the range of 10% to 40% of traveling wire, the total surface terminating in a substantially a stationary dewatering member in association with 10 straight line a uniform distance from the trailing the wire and having a dewatering surface, edge, said surface having a leading portion and a trailing a pivotal support for the dewatering member having portion relative to the direction of wire travel and a pivotal center substantially coincident with the having a leading edge and atrailing edge, radial center of said leading portion of the surface, the trailing portion of said surface being planar and an arm on said foil,

diverging away from the wire at a small angle, an adjustable support for said arm for changing the the leading portion of said surface being arcuate in angle between the trailing portion of the surface and shape and leading toward the wire to an engaging the wire, portion between said leading and trailing portions and indicator means on the dewatering member inproviding a space between the wire and said leading 2 dicating the angle between said trailing surface and portion, the wire. a mirror finished hard thin layer of coating on said 8. In a Fourdrinier papermaking machine having a surface having a finish in the range of 4 to 15 micro traveling wire, inches and extending from the leading edge toward a stationary dewatering member beneath the Wire havthe trailing edge covering only a portion of said deing an upper dewatering surface, watering surface with said surface adjacent the trailsaid surface having a leading portion and a trailing ing edge being free of coating and said coating terportion relative to the direction of wire travel and minating in a substantially straight line across the having a leading edge at the beginning of said leadlength of the dewatering member so that uniform ing portion, flow of water results from water removed from the the trailing portion of said surface being planar and web on the upper surface of the wire. diverging away from the wire at a small angle, 6. In a Fourdrinier papermaking machine having a the leading portion of said surface being arcuate in traveling wire. shape and leading upwardly toward the Wire to an a stationary dewatering member in association with engaging portion between said leading and trailing the wire and having a dewatering surface, portions, said surface having a leading portion and a trailing the distance between the wire and said surface at said portion relative to the direction of wire travel, leading edge measured when the wire is stationary the trailing portion of said surface being planar and being in the range of 0.006 to 0.012 of an inch so diverging away from the wire at a small angle, that the friction drag at the dewatering surface is the leading portion of said surface being arcuate in reduced to reduce the power required to drive the shape and leading toward the wire to an engaging wire and optimum dewatering of a Web on the Wire portion between said leading and trailing portions, is obtained. a mirror finish hard thin coating on said surface hav- 9. In a Fourdrinier papermaking machine having a ing a finish in the range of 4 to 15 micro inches and traveling wire, extending from the leading edge of the surface tO- a stationary dewatering member beneath the wire havward the trailing edge, ing an upper dewatering surface, said coating covering an area of said surface in the said surface having a leading portion and a trailing range of 10% to 40% of the total surface terminatportion relative to the direction of wire travel, ing in a substantially straight line a uniform distance the trailing portion of said surface being planar and from said trailing edge so that uniform dewatering diverging away from the wire at a small angle, and a uniform flow of water on said trailing surface the leading portion of said surface being arcuate in will occur from water removed from a web on the shape and leading upwardly toward the wire to an upper surface of the wire. I engaging portion between said leading and trailing 7. In a Fourdrinier papermaking machine having a portions, traveling i said arcuate leading portion covering an arc of a circle a stationary rigid dewatering member extending across in the range of 1 to 10 in length so that the fric the machine beneath the wire and having a dewatertional drag at the dewatering surface is reduced to ing surface, reduce the power required to drive the wire and opsaid surface having a l ing P i n and a trailing timum dewatering of a web on the wire is obtained.

portion relative to the direction of wire travel with a leading edge and a trailing edge, References Cited the trailing portion of said surface being planar and UNITED STATES PATENTS diverging away from the wire at a small angle, the leading portion of said surface being arcuate in 3,017,930 1/1962 Dunlap 162-352 shape and leading toward the wire to an engaging 3,239,409 3/1966 Knowles 162352 DONALL H. SYLVESTER, Primary Examiner. A. C. HODGSON, Assistant Examiner.

the arc of said leading portion having a radius in the range of between 0 to 10 inches and having an arcuate length of greater than 1 with the leading

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