US1757533A - Seal for preventing the flow of material between relatively moving surfaces - Google Patents

Description

FOR PREVENTI ETWEEN "RELATIVELY MOVING Filed July 12, 192

1,757,533 ATEBIAL asuamcs B. LEWIS NG THE FLOW OF M SEAL B May 6, 1930.

IHVENTDR Patented May 6, 1930 FATE. QFFICE WARREN B. LEW'IS, F SEEKONK, MASSACHUSETTS SEAL FOR PREVENTING THE FLOW on MATERIAL BETWEEN RELATIVELY MOVING suarncns Application filed July 12, 1928.

This invention relates to an improved seal for preventing. the flow of liquids or finely divided suspended material between relatively moving surfaces, and is'capable of application to various classes of liquid. media and variousfinely divided materials suspended in liquid media, although in the present embodiment of the invention the principle is applied to controlling the flow of a liquid which contains finely divided insoluble pulp held in suspension therein. The invention hereinis illustrated in connection with'paper making machinery and in its present embodiment comprises a screen mechanism and its associated parts such as is adapted to separate the foreign matter from the fine fibres and cellulose strandswhich are felted together in the manufacture of paper.

In the manufacture of paper the pulp is screened to separate wood, metal or dirt, or other particles from the fine fibres and cellulosestrands as a preliminary step to the removal of the water and consequent formation of paper sheets upon the usual type of paper making machine, and the invention is illustrated in connection with a rotatable screen such as is commonly employed in the Four drinier or cylinder machines for. screening the pulp preparatory to the formation of the paper.

in the screening of pulp preparatory to the manufacture of paper a cylindrical screen member provided with a plurality of small or openings is partially immersed in a container in which is a quantity of pulp suspended in water sufficient to bring the level. thereof materially above the lower portion of the screen whereby the fine fibres may pass througl'i the small screen openings towards the center thereof as the screen is rotated and flow out through the open ends of the screeninto asuitable trough from which the screened pulp may be drawn for making the paper, while the coarser particlesof foreign matter are unable to pass through the opens ings in the screen and are thus excluded from the screened material. In order to prevent tlieflow of unscreened pulp past the ends of the screen it has been the practice to mount the screen endsin an arcuate opening formed Serial No. 292,253.

in the side walls of the main pulp container and to provide cooperating oppositely positioned arcuate grooves in each wall and screen end, and place therein a section of tubular rubber hose or other packing which may be expanded by filling with water or by other means to entirely close the space between each end of the screen and the wall of the container. This method is open to various objections in that the filled hose sect-ion or other form of packing presses closely against each end of the screen and the corresponding partition wall, thus engendering considerable friction and requiring considerable additional power for rotating the screen. The surface of the packing is also subjected to con tinual wear and particles of the material are worn away and fall into the screened pulp where they pass on and produce imperfections in the paper.

One object of the present invention is to overcome these difficulties by providing an efficient means for preventing the flow of pulp past the screen ends which will not require increased power for rotating the screen and Which will overcome the difficulties heretofore experienced through the discharge of abraded foreign particles into the screened pulp.

Another object of the invention is to provide a screen of the character described which is of simple construction and capable of chicient operation in the separation of the coarser particles offoreign matter from the line fibres and cellulosic strands which go to make up the paper, and which is capable of being readily constructed and operated with less expenditure of power than devices of this character as heretofore employed.

A further object of the invention is to provide a screen of this character having improved means for preventing the flow of any portion of the unscreencd pulp past the free ends of the screen and into the screened pulp.

Another object of the invention is to provide an improved screen of the character clescribed provided with end rings having one or more circular ribs adapted to fit within corresponding grooves formed in a partition Wall or in an are shaped ring attached to the partition wall whereby the free flow of liquid or finely divided suspended material past the ends of the screen will be substantially prevented without materially interfering 'ith the free rotation of the screen.

Other objects and advantages of the invention relate to various improved details of construction and novel arrangement of the parts as will be more fully set forth in the detailed description to follow.

Referring to the drawings 2- Fig. 1 is a top plan view of that portion of a paper making machine which discloses the rotating screen for separating'the coarse particles from the line fibres and cellulose strands which are adapted to be felted together to form the paper.

Fig." 2 is a vertical sectional view, taken along the line 22 of Fig. 1.

Fig. 3 is an enlarged vertical sectional view, taken along the line 33 of F ig. 1, and,

Fig. l is an enlarged detail sectional view, taken along the line 4tl of Fig. 8.

c In the embodiment of the invention illustrated herewith 1 designates a shallow trough into which the unscreened pulp is discharged from the beater, stuff chest, or other suitable source of supply, and which trough communicates with a main pulp container 2 by a passage 3 through which the unscreened pulp passes by gravity; The main pulp container 2 may be of oblong shape as shown and the end portions thereof are separated from a screened pulp containersection 4 by partition walls 5. The screened pulp container section 4 may be in the form of a trough partially surrounding the main pulp container 2 and has portions separated therefrom by the partition walls -5 at points adjacent to the ends of the main pulp container 2. The screened pulp container section 4; is provided with an outlet 6 through which the screened pulp passes to the felting mechanism.

A cylindrical screen 7 is rotatably mounted in the main pulp container 2, the screen comprising a cylindrical plate or body port-ion, 8, provided throughout its surface with a plurality of relatively fine slots or openings 9,

and having the ends thereof secured to end rings 10, in any suitable manner, such as by means of rivets 11 passed through the end ring, the screen and a clamping ring 12. The end rings 10 at opposite ends of the screen are of similar construction, as are the means employed for connecting them to the screen. Each end ring 10 is provided with a plurality of spider arms 15, secured thereto in any suitable or desired manner, as by brazing, and extending outwardly from the ring to a shaft member 16 which is mounted for rotation in a bearing 17 carried by a portion of the machine frame- One of the shaft members 16 extends outwardly from the bearing 17 and carries a worm gear 18 which meshes with a worm 19 carriedby a shaft 20, whereby the screen may be rotated through a pulley 21 from any suitable source of power (not shown). The shaft member 16 located upon the opposite side of the machine is preferably hollow, and a pipe 24 is passed therethrough and extends substantially throughout the length of the cylindrical screen, that portion of the pipe 24 located within the cylindrical screen being provided with small openings 25 whereby water may be sprayed upon the interior surface of the screen to detach and wash away such cellulose fibres as may adhere to the interior surface of the screen.

The partition walls 5 at each end of the main pulp container 2 are provided with arcuate openings 28, adapted to receive the end rings 10, and the arcuate surface of each opening 28 as well as the outer circumference of each end ring is provided with inter: fitting ribs 29 and 30 respectively. While the ribs 29 and 30 carried by the arcuate surface of the partition wall and end ring respective ly are shown in the present instance as square or rectangular in cross-section, they may be of any desired cross-sectional shape, and the parts are so proportioned and the screen 7 so supported by the bearings 17 that the clearance space 31 between the ring 10 and the arcuate surface of the partition wall 5 is relatively slight, although suflicient to permit free rotation of the screen 7 without substantial friction between the rings and the arcuate surface of the partition Walls.

The space between the outer surface of the end ring and the exposed arcuate face of the partition wall, when the outer surface of the end ring and exposed face of the partition wall are provided with interfitting ribs, serves as a tortuous restricted passage which tends to obstruct the free passage of the coarser particles between these parts.

An opening 32 is preferably formed in each partition wall 5, outwardly of that portion of the frame 33 which serves as a base for supporting tie mechanism, which opening termin'ates in the space 31 between the arcuate opening 28 and the outer surface of the ring whereby water or other fluid medium may be fed into the clearance space 31 through a pipe 35 from a suitable source of water supply 36, located a sufficient distance above the axis of the screen 7 to give it the desired head for forcing it into all parts of the space 31 and entirely filling the same to the exclusion of any fluid tending to flow past the end of the screen and through the space 31 from the main pulp container chamber 2 into the screened pulp container 4. A valve 37 may be provided for regulating the flow of water through the pipe 35, and the opening 32 maybe provided at any desired point in the surface of the arcuate opening 28 although it is shown herein as located at the lowest point therein as better adapted to distribute water.

means liminary treatment and passed into the trough 1 from a suitable source of supply as will be clear to those skilled inthe art. From the trough 1 the finely divided pulp "suspend ed in a suit-able liquid medium, such as Water,

passes to the main pulp container 2in'sufe ficient quantity to rise above the lower-edge of the screen 7, which is slowly rotated-bythe shaft 20 through the worm 19 and worm gear 18. The level of the suspended material in the main pulp container 2 being above the lowermost portion ofthe screen, the pressure of the liquid tends to cause a flow ofthe more finely divided suspended material With its carrying liquid throughthersmall slotsor 2 1 opening into the inner portion of the screen from which place this material readilypasses to the screened pulp container section 4 through the open end or ends of the screen.

Theprovision of interfitting ribs 29 and 30 upon the arcuatesurfaces of each partition wall and end ring respectively provide a narrowtortuous passage 3-1 between each end ring and the corresponding partition wall, which may be made sufiiciently narrow; by

properly mounting the screen 7 in the bearings 17, as to preventf'by reason of its limited width, and without the use of fluid forced therein, the passage ofparticles of matter of sucli siZefas would be detrimental to'the product. v I v In order,however,to assure efiicient operaf tion, especially when employed for the sepa ration of more finely divided suspended material, orto provide -a more effective seal between the relatively movable surfacespI provide means for forclng a fluid into the clearance space 31, through the pipe 35 and opening 32fwhile in the present. instance I propose to employ water as the medium to beforcedintothespace31, since water the medium commonly employed for holding the pulp in suspensiomlmay, under certain circumstances; and in certain embodiments which my invention may assume in practice, emliiloyother liquid orgaseous media for this purpose, dependent upon the material in connection with wnich my invention may be employed and the purposes to be served by the fluid to be passed into the space 31, such as effecting lubrication of the moving surfaces or dissolving accumulated matter therefrom. The pressure under which the fluid is forced into the space 31 may be regulated as desired, dependent upon the material in connection with which the invention is used and the amount of clearance provided between the surfaces. In the present embodiment of my invention I may employ a relatively low pressure when a fair amount of clearance is provided as sutiicient for the purpose of filling the clearance space and preventing the entry therein of the coarser foreign particles as well as serving as a means for lubricating the movlng surfaces.

In. certain embodlments which my 1nvention may assume in practice, I may dispense with the interfitting grooves formed between the parition wall and end ring and by spacing the end ring avery slight distance from the arcuate surface of the partition wall and introducing fluid into the space between these members insuch amanner as to insure an adequate outward flow of such fluid throughout substantially the entire extent of the space between these parts, the outward flow of fluid may be made sufficient, to counteract the tendency of liquid or liquid suspended matter to pass between the end-ringandthe partition wall. While the structure has been shown and described withthe end rings en gaging the partition walls, and with inter-fittingribs formedupon the end ring and par;

titionwall respectively, for the purpose of simplifying the illustration, it, is regarded as preferable in order to overcome difficulties in construction, that a separate arcuateplate or semiannulus be formed and secured to the arcuate opening formed in the partition wall and that the ribs 29 be formed upon the separate arcuate plate instead of upon the partition wall itself. It is tobe understood therefore,thatin all cases where the ribs 29 are described orclaimed, as being formed upon the arcuate surfaceofthe partition wall it is my purpose and intent to either form the ribs upon the surface of the arcuatc opening in the partition wall itselfand mount the cylinder with the end rings thereof in cooperative relationship with the arcuatesurface of said partition wall, or to interpose an arcuate plate or seniiannulus between the curved surface otthe arcuate opening in the partition wall and the outer surface of the end ring, and when such arcnate plate or semiannnlusis employei'l the ribs adapted to cooperate with the ribs of the end ring will be formed upon that faceofthe arcuate plateiwhich is located in cooperative relation with the. outerfsurface of the end ring. In all cases. where such arcuate plate or semiannulus isemployed it will be firmly secured to the partition wall and the opening for supplying fluid to the space between the arcuate plate and end ring will be extended through saidarcuate plat l/Vhile I have shown an vention inits application to a screen for separating the finer portions of the pulp from the coarser particles thereof or fromsuclr coarse foreign matter as may be contained run-emirto be .unders toodthat it is caterials, colloids and the like".

d described din- It is to be understood that the invention is notto be limited .to the particular number of interfitting ribs .29 and and their correspondinggrooves as shown herein, but that a greateror less number of such ribs may be employed as desired, nor is the invention to be limited to the position of the opening 32 as shown, it being understood that such changesin the numberand shape of the ribs 29 EUR/1,30, and position of the opening 32. may be made as varying condltions of use 4 arcuate opening insaid partition wall, and

one or more circular ribs carried by the end portion of sald screen and fitting within said arcuate grooves to permit rotation of sald screen relative to said container while subuse stantially preventing the passage of coarse fluid suspendedmaterial from one section of thecontainer tothe other past said screen end.

scribed a 'fluid container provided with a partitionwall separating the-container into sec-- ti ons, an open tended screen rotatably supported in proximity to said container and adapted to screen'fluid material'passing from one of said sections to the other, and means for preventing the passage of fluid material from one of said. sections to the otherpast the end of said screen comprising interfitting ribs located in close proximity to but out of frictional engagement with each other and carried .by said partition wall and screen re spectively.

3. In a mechanism of the vcharacter described, a fluid container provided with partition walls separating-said container into sections, a screen rotatably supported in proximity to said container and separating certain of said sections from the others, means forpreventmg free flow of fluid material past the end portions of saidscreen comprising interfitting ribs carried by the end portions of said. screen and said partition walls respectively, and means for forcing fluid into the spaces betweensaid interfitting ribs. a r

4.In'amechanism of the character described,,arotatable cylindrical screen having an open end provided with an end ring, an arcuate seat cooperating with said end ring, said cooperating and ring and seat'being ar- 2. In ,a. mechanism of the character derangedin close proximity to but out of frictional engagement with each other and provided with inter/fitting ribs.

5. In a mechanism of the character described, a rotatable cylindrical screen having open ends and provided with end rings located at oppositeends of the screen portion, arcuate seats cooperating with said end rings, said cooperating rings and seats being arranged in close proximity to but out of fric tional engagement with each other and provided with interfitting ribs, and means for forcing fluid into the spaces between said cooperating rings and seats at a point intermediate the sides thereof. 7 V

6.- In a device of the character described, a stationary member provided with an arcuate seat, a rotatable member comprising a ring located in cooperative relation with said arcuate seat, and means for preventing the flow of liquid suspended material between said seat and ring comprising interfitting ribs carried by said seat and ring respectively and means for forcing fluid into the space between said seat and ring at a point intermediate the sides thereof.

I 7. In a device of the character described, a stationary member provided with an arcuate seat, a rotatablermember comprising a ring located in cooperative relation with said cuate seat, a rotatablemember comprising a ring located in cooperative relation with said arcuate seat, and interfitting means between 7 said seat and ring in close proximity to but out of frictional engagement with each other for forming-a tortuous passage therebetween to prevent the flow of liquid suspended material between said seat and ring.

In testimony whereof I have aflixed my signature. I

WARREN B. LEWIS.

arcuate seat, the outer surface of said ring

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