US3105045A

US3105045A - Centrifuge discharge means

Info

Publication number: US3105045A
Application number: US163995A
Authority: US
Inventors: Walter A Borig
Original assignee: Sharples Corp
Current assignee: Sharples Corp
Priority date: 1962-01-04
Filing date: 1962-01-04
Publication date: 1963-09-24
Anticipated expiration: 1980-09-24

Description

Sept. 24, 1963 w. A. some CENTRIFUGE DISCHARGE MEANS I Filed Jan. 4, 1962 ATTORNEY United States Patent 3,105,045 CENTRIFUGE DISCHARGE MEANS Walter A. Borig, Wayne, Pa, assignor to The Sharples Corporation, a corporation of Delaware Filed Jan. 4, 1962, Ser. No. 163,995 2 Claims. (Cl. 23322) This invention relates to the separation of solids from liquid. More specifically this invention relates to an apparatus for separating solids from liquids by centrifugal force and provides means for facilitating the discharge of the solids.

In the prior art, apparatus for separating solids from liquid has comprised an imperforate rotor and a screw within the rotor operatively connected to the rotor for relative movement between the rotor and the screw upon rotation of the rotor. Liquid and solids discharge openings have been provided at opposite ends of the rotor and means have delivered feed into the rotor at a point intermediate the ends. In operation, the solids in the feed have, under centrifugal force, been thrown against the wall of the rotor and the screw, moving relatively to the rotor, has plowed the solids toward the solids opening for discharge. The liquid, separated from the solids, has discharged through the liquid opening.

Apparatuses of the general type with which the present invention is concerned are disclosed, for instance, in US. Patent 2,703,676, issued March 8, 1955, on application filed by F. P. Gooch, and also US. Patent 3,061,181, issued October 30, 1962, on an application filed by F. P. Gooch.

In such prior art devices difliculty has occasionally been experienced by the tendency of some solids discharging from the rotor to cling to the inside surfaces of the surrounding casing and to build up thereon inwardly to the rotor. This action has been especially manifest with discharged solids having a higher liquid content. Such accumulation has serious consequences: further discharge of solids from the bowl is impeded; and the interference of accumulated solids with the rotor requires greater power to rotate the rotor and leads to a condition of axial imbalance in suspended rotors, resulting in severe vibrations.

"in the past, attempts have been made to facilitate solids discharge. A rigid metal fabricated shield has been mounted to surround the rotor inside the casing in the zone of solids discharge. Special mounting of the shield has enabled the shield to be vibrated by either an electric or air-operated vibrator disposed outside the centrifuge casing. While to some extent the powered shield has prevented the accumulation of sticky wet solids inwardly toward the rotor, it has obviously involved undesirable expense, has been subject to break-down and has required maintenance. More importantly, when a centrifuge is used in a process requiring pressure operation, penetration of the centrifuge casing for the shield driving arm is obviously undesirable.

I have developed an extremely simple yet effective means for eliminating solids accumulation in the solids discharge zone. My means is inexpensive, is self-actuating, is not subject to break-downs, and requires no maintenance.

Other features of my invention will be apparent from the following specification of which the accompanying drawings form a part.

In the drawings,

FIGURE 1 is a perspective partly in section of an apparatus embodying my invention; and

FIGURE 2 is an enlarged fragmentary sectional View taken on the line 2--2 of FIGURE 1.

Briefly, in a centrifuge comprising a rotor having at ice least one solids discharge opening, my invention is the improvement of a curtain of smooth flexible sheet material at least partially circumposing the rotor in the zone radially outward from the discharge opening and there being free for limited lateral movement. The curtain, vibrated by impact of solids discharge, and by centrifuge windage precludes adherence and inward accumulation of solids. Additionally, the smooth surface of the sheet material contributes in large measure to the effectiveness of the improvement.

Referring more specifically to the drawings, an apparatus embodying the invention is generally designated 10 in FIGURE 1. It comprises a casing 12 which mounts for rotation about a vertical axis a rotor 14. Drive means (not shown) rotate the rotor from its upper end and comprise, for instance, belts disposed under the guard 16. The rotor 14 contains a screw 18 to which it is operatively connected for relative movement as disclosed, for instance, in the latter above-mentioned patent application. A drag 243 is supported from the casing 12 on radial arms 22 for the purpose of limiting axial aberrations of the lower end of the rotor. A feed tube 24 from an appropriate source penetrates the casing 12 and extends through the drag 24) for the purpose of delivering feed mixture into the rotor as is well known in the art.

In the operation of the apparatus, feed mixture is conveyed, e.g. as by pump, through the feed tube 24- and into the rotor 14 at a central location, for instance. The rotor in rotating causes the solids of higher density than the liquid to move outward to the wall, and the screw, the flight edges of which are proximate to the wall, plows the solids to the discharge openings 26 from which they are thrown outwardly. The liquid discharge means is not shown.

The portion of the apparatus which embodies my invention is shown in FIGURE 1 to comprise a continuous sheet 28 of thin material circumposing the rotor and spaced intermediate the casing and the rotor. As shown in FIGURE 2 the mounting for the sheet 28 comprises an inward flange 3t) secured about the casing at a level well above the openings 26. The flange 3t} secures an annular plate 32 which in turn supports a bracket 34 comprising an outer clamping ring 34a. An inner clampin ring 36 is provided and rings 34a, 36 sandwich between them the upper end of the sheet 28 and, along with the sheet, are suitably apertured to receive a plurality of circumferentially spaced mounting bolts 38.

From the upper mounting assembly the sheet 28 comprising the curtain is freely suspended in the embodiment shown and extends to a level well below the discharge openin s 26. The lower end of the sheet 28 is sandwiched by a pair of lower clamping rings 49, 42. The rings, together with the sheet, are suitably apertured to receive oir-cumferentially spaced clamping bolts 44, the outer ends of which extend outward from the rings 49, 42 to comprise stop elements for the purpose of limiting the lateral travel or" the lower end of the curtain, to keep it under control. The rings 40, 4-2 provide weight suflicient to hold down the lower end of the curtain but not suflicient to prevent movement of the curtain by impact of the solids and by the air currents about the rotor. The

rings

40, 42 also serve to hold the lower end of the curtain in shape.

As shown in FIGURE 1 ample openings 45 are pro vided in the sheet 28 to permit penetration by the radial arms 22 and the feed tube 24.

The preferred material for sheet '28 is Teflon. Teflon is a Du Pont trademark for polytetrafiuoroethylene. Thickness of about inch has been found suitable. Other materials, having smooth surfaces and considerable flexibility are eliective to some extent and may be used.

In operation, the solids thrown outward from openings 26 impact against the sheet or curtain 28 causing it to vibrate. This vibration, enhanced by air currents about the rotor and controlled in amplitude by the length of the stop elements 44, serves to preclude adherence of the solids to the sheet 28. Assisting greatly in precluding adherence may be the smooth and slippery character especially of the preferred material of the sheet 28.

It should be understood that While the rotor disclosed has its lower end of generally conical shape, the invention may be applied to a rotor of cylindrical shape if desired.

The lower end of the curtain may be loosely connected to the casing if desired, provided such mounting does not interfere with the freedom for lateral movement of the curtain in the zone of solids discharge. -It should be understood, however, that the embodiment shown has been found especially cfiective.

While the curtain is most eifectively applied to a rotor having a vertical axis, it may be used with some benefit on a rotor having a horizontal axis by supporting the curtain at both ends and by modifying the curtain to provide openings for solids discharge through a portion thereof disposed below the axis. However, application to a vertical machine is preferred.

It is, therefore, to be understood that the above description is by way of illustration and that changes, omissions, additions, substitutions a-ncl/ or other modifications may be made without departing from the spirit thereof. Accordingly, it is intended that the patent shall cover, by suitable expression in the claims the various features of patentable novelty that reside in the invention.

I claim:

1. In a centrifuge comprising a rotor having a vertical axis and having at least one solids discharge opening, and a stationary casing enclosing said rotor, the improvement 4 of a curtain of smooth flexible sheet material circumposing the rotor and spaced inward from the casing at the level of the solids discharge opening and therebelow, a pair of clamping rings circumposing the rotor and secured to the casing at a level above the solids discharge opening, the top of the curtain being clamped between the clamping rings, the curtain hanging downward therefrom, the lower end of the curtain having rigid annular weight means secured thereabou-t, the weight means having a plurality of peripherally spaced radially outstanding stop elements to engage the casing and thereby to limit the lateral movement of the lower end of the curtain, the curtain being free for lateral movement in all radial directions in the zone outward from the solidsdischarge opening whereby solids in discharging hit the curtain and vibrate it to preclude solids buildup thereon.

2. A centrifuge as described in claim 1 wherein the flexible sheet material is Teflon.

References Cited in the file of this patent UNITED STATES PATENTS 631,680 Staahlgren Aug. 22, 1899 735,524 Kessler Aug. 4, 1903 2,045,986 Gould -5 June 30, 1936 2,186,836 McGlaughlin Jan. 9, 1940 2,272,175 Jordan Feb. 10, 1942 2,324,933 Jones July 26, 1943 2,367,961 Piponius Ian. 23, 1945 2,661,150 Abbott Dec. 1, 1953 2,703,676 Gooch Mar. 8, 1955 3,014,642 Lundberg Dec. 26, 1961 3,053,762 Adiletta Sept.'11, 1962 3,061,181 Gooch Oct. 30, 1962

Claims

1. IN A CENTRIFUGE COMPRISING A ROTOR HAVING A VERTICAL AXIS AND HAVING AT LEAST ONE SOLIDS DISCHARGE OPENING, AND A STATIONARY CASING ENCLOSING SAID ROTOR, THE IMPROVEMENT OF A CURTAIN OF SMOOTH FLEXIBLE SHEET MATERIAL CIRCUMPOSING THE ROTOR AND SPACED INWARD FROM THE CASING AT THE LEVEL OF THE SOLIDS DISCHARGE OPENING AND THEREBELOW, A PAIR OF CLAMPING RINGS CIRCUMPOSING THE ROTOR AND SECURED TO THE CASING AT A LEVEL ABOVE THE SOLIDS DISCHARGE OPENING, THE TOP OF THE CURTAIN BEING CLAMPED BETWEEN THE CLAMPING RINGS, THE CURTAIN HANGING DOWNWARD THEREFROM, THE LOWER END OF THE CURTAIN HAVING RIGID ANNULAR WEIGHT MEANS SECURED THEREABOUT, THE WEIGHT MEANS HAVING A PLURALITY OF PERIPHERALLY SPACED RADIALLY OUTSTANDING STOP ELEMENTS TO ENGAGE THE CASING AND THEREBY TO LIMIT THE LATERAL MOVEMENT OF THE LOWER END OF THE CURTAIN, THE CURTAIN BEING FREE FOR LATERAL MOVEMENT IN ALL RADIAL DIRECTIONS IN THE