US1946500A - Basket lining for centrifugals - Google Patents

Description

Fein'. 13, v1934. E. ROBERTS l 1,946,500

` BASKET LINING FOR CENTRIFUGALS Filed Jan. 28. 1933 Patented Feb. 13, 1934 UNITED STATES Pill'riezN'r.` oFFicE 1,946,500 BASKET IINING FOB CENTRIFUGAIS Eugene Roberts, Hastings, N. Y., assigner to The Western States Machine Company, Salt Lake City, Utah, a corporation of Utah Application January 2s, 1933.k sex-inl No. 654,042 'z claims. (ci. 21o-1s) of the material around the tcp and bottom edges' of the basket lining, thus producing imperfect and unsatisfactory centrifuging. It is the object of the present invention toprovide an element of the filter structure with a construction that shall eliminate this objectionable leakage and thus give full eil'iciency to the centrifugal separation 2o of liquid from the solid content, while in no way interfering with the correct positioning of the filter lining in the basket or with its effectiveness inperforming its function of retaining the solid particles or grains, while allowing free escape of the liquid.

Broadly speaking, the improvement comprises an open grid lining for drainage, whose circumferential edge or edges are provided with a narrow thin strip of packing intimately united with the marginal portion of the lining member and projecting a slight distance beyond the edge of the lining member to form close contact with the adjacent rim of the centrifugal basket. Ordinarily such a packing strip will be applied to both the top and the bottom edge portions of the per- Fig. 1 is an elevation showing a perforated backing or lining grid, provided with the integrally attached packing strips, affording drainage mpport for the nlter elements.

Fig. 2 is a cross sectional view on an enlargedo scale of a nltering structure arranged inside the centrifugal basket and containing the present improvement. 1 i

Flg.3isanedgeviewshowingthelapjointof thebridge member.

Flgad, 5 ando are detailviewsshowing the grid construction insection and in elevation. respectively. o

In the practice of my invention according to the form illustrated in the drawing, the particular filter structure .comprises a spacing grid 1 having 60 relatively large openings or interstices fitted against the inside of the perforated basket wall 10, which wall is provided at the top with an annular rim 11 and at the bottom withan annular rim 12, which latter is secured in the usual mano5 ner to the customary open spider carried by the 'central supporting and driving shaft present in all centrifugals.

Inside the coarse wire mesh grid 1 is plac'ed a perforated lining sheet or backing 2, whose vertical width is slightly less than the vertical distance between the top and bottom rims of the basket,-thereby permitting easy insertion ofthe perforated sheet or plate 2 without causing buckling due-to the wedging of its top or bottom edge against the rigid subtending rims ofv the basket.

It is not commercially practicable to make parallel the edges of the mesh forming the drainage gridfwhich spaces the filtering elements from the perforated basket wall, because of the distors0 tion of the wire fabric while it is being woven, but by providing the top and bottom edges of the wire grid with packing selvages 3 of material like soft vulcanized rubber, it is possible to secure satisfactorily parallelism between the top and bottom edges of the -selvage portions of the ygrid element, so that the complete grid may be made of the' proper vertical width to permit the use of such a grid that will fit snugly between the top and bottom rings of the centrifugal basket. Hence, a basket measuring 24 inches between the top and bottom rings may be tted with a 24 inch wide grid lining, so that there is no possibility of leakage of material around the top or bottom edges of the lining which is a common fault es with the lining constructions heretofore used. In practice, the opposite longitudinal, orwhat will be the circumferential edges of the grid is placed in molds that embrace these two edges of the wire mesh or grid member, in which a rubber composition is placed and the rubber composition is then vulcanized to a moderate degree,the mold being dimensioned to form the rubber selvages of substantially the same thickness as the thickness of the woven mesh and projecting outward beyond the ragged edges of the mesh to form edge portions that are in parallelism with each other.

To facilitate the forming of a smooth joint between the lapped ends ofthe grid. several vertical orcross wires are withdrawn from 4the op- 11o in Fig. 1, and the end portions of the rubber selvage or border are bevelled to a thin edge, so that when overlapped they will be of the same 5 thickness as other portions of the selvage, as shown at 3P- in Fig. 3. 'Ihis is practicablel because there is no substantial stretch to this coarse wire mesh member after it is properly fitted into the basket. The projecting ends le of the circumferential wires, from `which the coarse wires have been stripped as above explained, will lap by each other in side by side relation, as shown in Fig. 2, so as to afford -an intermediate support for the interior filter elements which restagainst the grid and which are held. by it in spaced relation from the basket in order to afford adequate drainage passages to the relatively large perforations in the basket wall.

The filter elementsmay be of anysuitable construction and in this case are shown as comprising an intermediate bridge or supporting plate 2 provided with relatively coarse perforations and against the inner face of this bridge plate is mounted a finer wire mesh backing 7 forming a spacing support for the finely perforated sheet metal lining 6. This construction is similar to that shown in'my earlier patent No. 1,581,089. Since the perforated bridge plate 2 has its top and bottom edge portions resting directly against the compressible rubber selvages 3, which may be 1/2 inch more or less in widthyit is not necessary to have the bridge plate or the other filter elements 6 and 'I nt snugly inside the top ring 11 and the bottom ring 12 of the basket, and yet leakage of material around the top and bottom edges of the lter linings is completely eliminated. While it is preferred that the basket wall 10 shall have its top and bottom rows of perforations spaced a substantial distance from the adjacent top and bottom rings of the basket in order to afford a smooth continuous support for the selvage edges of the lining or grid, nevertheless such an arrangement is not essential.

In Figs. 5 and 6 is shown a slightly modied form of joint for the spacing grid, in which the projecting ends 1b of the circumferential wires, from which the crossed wires have been stripped, are bevelled to a thin edge or point and are overlapped upon the adjacent portion of the wire mesh containing the cross Wires. In this case a somewhat longer bevel is given to the overlapping end portions of the selvages 3 so as to avoid any substantial increase in thickness at the lapped joint. Y

By means f the above described construction .it is possible not only to practically eliminate the wasteful leakage of material around the edges of the lter linings, but the advantage is also secured of facilitating the insertion of the lter 50 elements themselves because they may be cut somewhat narrower than the inside vertical width of thebasket, since the packing selvages or borders on one of the lining elements nt snugly 'inside the top and bottom members of the basket.` Heretofore it has been the practice to make centrifugaly baskets with the top row of outlet holes close up to the top rim of the basket, but I have shown in Fig. l2 the top row of holes located some distance below the inside of the top 70 rim 11 to afford a somewhat unbroken surface 'for the selvage portion .of the backing grid and `I have followed the same practice at the bottom of the basket by leaving blank the bottom area of the basket wall for a short distance to form a similar support for the selvage 3 of the backing' posite end portions of the wire mesh, as shownI grid. This arrangement affords a smooth, even disposition of the selvage edges perfectly sealing the basket against the escape of liquid around the bottom or around the top edges of the filter linings.

What I claim is:

1. A foraminous filter supporting grid element for a centrifugal basket having relatively large openings for the passage of liquid, the upper and lower edge portions of said grid being provided with circumferentially extending selvage strips of yielding material adapted to form sealing con tact with the inside face of the basket adjacent to the top and bottom members thereof to pro'- vide a drainage support for an interiorly disposed iiltering element, while preventing leak-Y age of the material being treated around the edges of the filtering element.

2. A grid l.backing for the ltering elementof a centrifugal basket comprising a course wire mesh grid adapted to be fitted inside the basket to afford drainage support for the ltering structure and having its top and bottom edge portions included within top and bottom selvage strips of vulcanized rubber adapted to form sealing contact with the adjacent surface of the basket to prevent leakage of Ithe material being treated around the top and' bottom edges of the filter structure.

3. A supporting drainage grid for a lter comprising a coarse wire mesh fabric having its top and bottom edge portions imbedded in top and bottom selvage strips of vulcanized rubber projecting somewhatI beyond the wire mesh to form top and bottom parallel packing strips adapted 110 to lie in close contact with adjacent surfaces of the basket to provide sealing joints against the escape of material being treated around the edges of the ltering structure.

4. A spacing and supporting grid for the filter 115 element of a centrifugal basket embracing in its construction, a coarse wire mesh having its top and bottom edges imbedded in parallel strips of vulcanized rubber substantially equal in thickness .to the thickness of the wire mesh grid and having their outer portions extending somewhat beyond the wire mesh to form compressible parallel seal- -ing edges at top and bottom of the grid.

5. A grid lining element for a centrifugal basket embracing in its construction, a relatively 125 coarse wire mesh fabric having its top and bottom edges imbedded in parallel selvage strips of vulcanized rubber substantially equal in thickness to the thickness of the wire mesh, the end portions of said selvage strips being bevelled to arthin edge to form, when the grid is inserted in the basket, a lapped joint/of a thickness substantially equal to other portions of the selvage.

6. A grid lining element for a centrifugal basket embracing in its construction, a relatively coarse wire mesh fabric having its top and bot-4 ,tom edges imbedded in parallel selvage strips of vulcanized rubber substantially equal in thickness to the thickness ofthe wire mesh, the end portions of said selvage strips being bevelled to a thin edge to form, when the grid is inserted ln the basket, a lapped joint of a thickness substanv tially v:equal vto other portions of the selvage, the vertical wires of the mesh at the 'overlapped ends of the grid being removed to permit the end por- 145 l tions of the circumferential wires to lap by each other in side by side relation to form support for the filter element at the 'overlapping joint.

,7. The combination with a centrifugal basket for the extraction of liquid comprising a perlpheral perforated basket wall and top and bottom rings secured thereto,

Said rings being spaced a substantial distance from the next row ot perforations in the peripheral unbroken surface for the ing elements, and a. iilter at top and bottom with a wall to afford a smooth support of the lter 1inlining element provided selvage oi' packing mathe lining.

` EUGENE ROBERTS.'

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