US1664996A

US1664996A - Centrifugal pulp screen

Info

Publication number: US1664996A
Application number: US179773A
Authority: US
Inventors: George F Shevlin
Original assignee: George F Shevlin & Son
Current assignee: George F Shevlin & Son
Priority date: 1927-03-31
Filing date: 1927-03-31
Publication date: 1928-04-03
Anticipated expiration: 1945-04-03

Description

G. F. SHEVLIN CENTRIFUGAL PULP SCREEN April 3, 1928. 6 1,664,996

Filed March 51. 1927 2 Sheets-Sheet 1 TW Ill I W III! 25/ IP52? l Eum! Win25 INVENTOR Patented Apr. 3, 1928.

UNITED STATES ATENT OFFICE.

GEORGE E. snnvnrn, or e-Lnns FALLS, new YORK, ASSIGNOR To GEORGE E. sHEvLIN & son, or GLnns FALLS, NEW YORK, A PARTNERSHIP GOMPOSEID or GEORGE I. SHEVLIN, SR, AND GEORGE E. SHEVLIN, JR.

CENTRIFUGAL PULP SCREEN.

Application filed March 31, 1927.

The present invention relates to an improvement in centrifugal pulp screens and more particularly to the stock distributor or runner element thereof. The invention furthermore is an improvement on the centrifugal pulp screen stock distributor as shown an described in U. S. Letters Patent No. 1,436,411, granted to me, November 21, 1922. The primary object of the invention in this case as in the construction shown and described in the Letters Patent aforesaid is to obtain an even distribution of the stock in forcing or directing the same against the screen. The apparatus as shown in the patent includes a centrally disposed hub, a cylindrical member arranged concentrically with the hub and connected therewith by a series of spaced preferably radially placed blades which extend beyond the cylindrical member, together with a series of vanes, there being a vane associated with that portion of each blade which extends beyond the cylindrical member and in the cylindrical member there are sets of ports or openings making passageways through the same adj acent the inner ends of the vanes, which vanes extend from the top or upper end of the distributor to a point approximately midway thereof.

It has been found in the use of a stock distributor or runner of this type that in some instances it operates satisfactorily. In other instances, however, particularly with pulp stock of certain consistencies, the stock or a large portion thereof in passing through the apertures in the cylindrical member is projected directly against the screen without the intervention of the vane. In such instances, of course, the stock is not projected with the force with which it would have been pro j ected through the action of centrifugal force when caused to pass along the surface of the vanes. Consequently, in carrying out the present invention and in order to make the apparatus fully effective with pulp stock of substantially all consistencies, I employ a plurality of deflector plates each associated with one of the vanes so that as the stock passes through the port in the cylindrical member the deflector plate directs the same positively to the corresponding vane, thereby obviating all possibility of any of the stock being projected directly from the port or aperture in the cylindrical member Serial No. 179,773.

through which it passes to the screen, and thereby utilizing the vanes to their fullest capaclty 1n imparting swift motion to the stock as the same is delivered therefrom against the screen of the apparatus.

In carrying out the present invention I employ suitable means for adjusting or regulating the passage of the stock from the central compartments to the exterior thereof so that depending upon the consistency of the stock and the speed of the apparatus, an even distribution of thestock and a maximum ehiciency of the apparatus may be attamed.

The invention will be hereinafter more particularly described in conjunction with the accompanying drawings in which 1*1gure 1 is a sectional plan on line 1-1, Fig.

Fig. 2 is an elevation of a stock distributor or runner for a centrifugal screen asmade in accordance with this invention. Fig. 3 is a sectional elevation on line 33, Fig. 1, and i Fig. 4 is a perspective View on an enlarged scale illustrating one of the deflector plates.

Referring to the drawing it will be seen that in carrying out the invention the stock dlstributor or runner made in accordance therewith is so constructed as to include a hub 10 adapted to be mounted on and connected to a suitable shaft by which it may be turned rapidly. The hub 10 is connected to a cylindrical member 11 by means of a series of blades 12 which are preferably placed in radial positions and divide the space between the hub and the cylindrical member into a corresponding number of compartments orspaces13. Each blade 12 extends appreciably beyond the cylindrical member as indlcated at 14. The top of the distributor is preferably flat as indicated at 15, and

the bottom is preferably made concavo-convex as'indicated at 16. The blades 12 and their extensions 14 preferably extend from the top to the bottom of the runner.

I also employ a plurality of vanes indicated at 17. There is a vane associated with each of the extended portions 14 of the ribs and an adjacent portion of the cylindrical member 11. These vanes 17 extend from the top or upper portion of the distributor to a point approximately centrally thereof, that is midway of its height. In the wall of the cylindrical member between each of the extensions 14 of the blades, I provide a port indicated at 18. This port is preferably an elongated rectangular slot and is adaptedto be covered to a greater or lesser extent by a door 19 so as to determine the area of the port and consequently the amount of: stock Vwhich under given conditions may pass and substantially coextensive therewith and longitudinally of the distributor. As illustrated; in the drawing, the deflector plates are designated at 22 and as shown in Fig.

4, the body of the plate is curx' ed and at one end formed with a' flange 23 adapted to fit 1n a recess or to extend through the upper portion of the corresponding blade extension 14 and to be connected to the top wall of the distributor by means of a rivet or screw 24. At the inner or lower end each deflector plate is formedwith a bracket 25, a portion of which is adapted to bear against the adjacent surface of the corresponding blade extension 1 1 and to be connected thereto by means of bolts. 26 or otherwise so as to secure the deflector plate in positionin the apparatus.

Below the vanes 17' and the associated defiector plates the cylindrical member 11 is provided in suitably spaced positionswith a plurality of holes 27 an'dalso with spaced slots 28. It will furthermore be noted that there is an appreciable space between the lower or inner end of the cylindrical member and the'upper face of the concavo-convex bottom plate 16, which space is indicated at 29.

In the use of this apparatus the stock is supplied through any suitable means to the compartments 13 between the hub 10 and the cylindrical member 11. From these. com partments as indicated by the arrows, the stoclcpasses through the ports 18 and di rectly against the deflector plates 22 by means of which the stock is directed positively to the corresponding-vanes'so that none of the stock can be projected directly through the opening or port in the cylindrical member tothe screen. Consequently the action of centrifugal force due to the rapid rotation of the distributor or runner imparts a rapid fiowto the stock causing the same as it leavesthe runner to be projected with considerable force against the screen. This action as will be understood, applies to the lighter portion of the stock as the apparatus utilized for this purpose is in the upper portion of the distributor. 'Ihe heavier portion of the stock passes in a customary manner toward the bottom of the compartments in the cylindrical member and passes through the openingsor ports 27 and 28 therein and project-ed against the screen by the extensions 14 of the blades. Furthermore, that portion of the stock which is not delivered in either of the manners to whicl'i reference has been. made, is permitted to pass by way of the space 29 to the upper surface of the bottomot the distributor and thence to the pipe lines or other means through which the sliversmay be discharged.

I claim as my invention: f

1. In a centri'higalpulp screen, a stock. distributor comprising a hub, a cylindrical member, blades extending from the hub toaud beyond the-cylindrical member, a plurality of vanes each associated with the outer portion of the cylindrical member and an adjacent portion of one of the blades, and

a plurality of deflect-or plates each associated with awvane and so constructed and secured in position as to positively direct the passage of stock to the corresponding vane. v

2; Ina centrifugal pulp screen, a stockdistributor comprising a hub, acylindricai" member, a plurality ofblades extending there being a port through the wall of the- V cylindrical member between each of the parts of the blades extending beyond the same, means for controlling the discharge 0& stock through the said ports, and a plurality of deflector plates each associated with one of the said vanes and adapted to direct the flow of the stool: as the same passes through one of the said ports to the corresponding vane. a. s

3. In a centrifugal pulp screen, a stock distributor comprising a hub, a cylindrical' member, a plurality of blades extending from the hub to and. beyond the" said cylindrical member, the cylindrical member having a series of portstherein, each port being placed adjacent one of'the extended portions of a blade, a corresponding numberof doors each controlling a port, means for adjusting the position of each door to determine the area. of the corresponding port, a plurality o'fivaneseachassociated with an outer portion of one of the blades and. the adjacent portion of the cylindricalmemben, and a plurality of deflector plates each adapted to direct the flow of stock ass-the same passes through the corresponding port to the corresponding vane.

1. In a ccntrifiugal pulp screen, a stock distributor comprising a hub, a cylindrical member concentric.therewith, a plurality oi? blades extending from the hub to" and be yond the said cylindrical member, there being a plurality of ports in the wall of the cylindrical member, each port being adjacent a blade, a plurality of doors each associated with one of the ports, means for adjusting each door to position to determine the area of the corresponding port, a plurality of vanes each extending from the top of the distributor to a point approximately midway of its length and associated With the outer portion of a blade and the adjacent portion of the Wall of the cylindrical member, the said ports and doors being also sub stantially coextensive of the extent of the said vanes, and a plurality of deflector plates each associated with a corresponding vane and adapted to direct the flow of the stock as the same passes through the corresponding port to the corresponding vane.

5. In a centrifugal pulp screen, a stock distributor comprising a hub, a cylindrical member concentric therewith, a plurality of blades extending from the hub to and beyond the said cylindrical member, there ity of vanes each extending from the top of the distributor to a point approximately midway of its length and associated With the outer portion of a blade and the adjacent portion of the wall of the cylindrical member, the said ports and doors being also substantially coextensive of the extent of the said vanes, and a plurality of deflector plates, each deflector plate being curved and secured in position to the outer portion of one of the said blades so as to extend over a corresponding port with Which it is sub- 1927 GEO. F. SHEVLIN.