|Publication number||US2635617 A|
|Publication date||Apr 21, 1953|
|Filing date||Oct 22, 1948|
|Priority date||Oct 22, 1948|
|Publication number||US 2635617 A, US 2635617A, US-A-2635617, US2635617 A, US2635617A|
|Inventors||Condell Raymond H|
|Original Assignee||Sharples Corp|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (7), Referenced by (6), Classifications (7)|
|External Links: USPTO, USPTO Assignment, Espacenet|
A ril 21, 1953 R. H. CONDELL' CENTRIFUGAL VALVE ASSEMBLY Filed Oct. 22, 1948 Inventor ymond hf Condel/ 2 a Attorney Patented Apr. 21, 1953 '-u,:1v1reo STATES PATENT OFFICE .ciinrmrcezfi il iie ASSEMBLY Raymond 3H. (Jonas-11, Philadelphia, Pa., assignor to "The Sharples :Oorporation, a corporation in! Delaware Application was 22, 1948, serial no. 555.998
(01. in -sol This invention relates to a centrifu'gally operated valve particularly adapted for use in centrifuges. H g I It iscommon practice to construct certain types of centrifugal machines in such a manner that the bowl rotates about a vertical axis. In this event, the liquid that is to be clarified or separated is fed to the centrifuge upwardly through the bottom of the rotating bowl. As long as the fmachine is operating above a certain speed, the liquid that is fed in at the bottom runs out at the top after clarification or separation, a the case maybe. However, when the machine is stopped, the effect of gravity becomes greater than the substantially horizontal effect of centrifugal force, so that any liquid remaining in the bowl ordinarily flows out the bottom 'of the centrifuge. This result must be avoided in the preparation 'ofcert'ain serums in order to prevent contamination of the liquid in the bowl and for this reason the remaining liquid should not come in contact with any surface outside the bowl, since such outside surface may not be sterile.
In virus preparation, it is customary to feed liqu-id containing the virus through the centrifuge at low capacity. The high centrifugal force of the rotating bowl retains the virus concentrate against the inside wallio'f the bowl, whereas relatively virus-free 'liquid'is discharged from the top of the bowl. In this operation, the liquid is fed for periods as long as eight hours in order to gradually accumulate the concentrated virus in the bowl. During the run, the separated liquid is removed, thus leaving the concentrate in the bowl and it is this concentrate which must be maintained in a sterile condition, not .only when the centrifuge is operating at normal speed "but when the machine is'decelerating, as well as when the bowl has completely come to rest. Furthermore, it is important that the bowl may be removed from the centrifuge without danger or the virus concentrate'being lost from the bowl. The present construction contemplates provision of an automatic check valve located at the bottom of the bowl, which completely prevents draining the bowlthrough the bottom thereof.
A primary object therefore, of my invention, is to provide'a centrifugally operated check valve for centrifuges which is simple, inexpensive to manufacture, and which may be kept thoroughly sterile at .all times. i V
A further object of the invention is to provide an annular resilient ring adapted to close the intake passages at the bottom of the bowl when the bowl is stationary or substantially so, but
2 open when the rotational speed of the bowl approaches its normal operatingvalue.
A further object is to provide a resilient check valve for each individual feed passage at the bottom of the bowl, the function of the check valves being to close the passages to prevent out- Ward flow of liquid but to permit inward flow of liquid when the centrifugal'force is suflicient to spring the valves away from theirseats.
Further objects will'be apparent from the specification and drawings in which:
Fig. 1 is a sectional detail showing a centrifugal valve constructed in accordance with the invention, installedin a centrifuge bowl;
Fig. 2 is a view similar to Fig. '1 but with the valve in an expanded position as would occur when the bowl is rotating athig h 'speed;
Fig. '3 is an exploded view showing in perspective the elements of the valve construction; and
Fig. 4 is a sectional view on a reduced scale of a modified form of centrifugally operated valve.
Referring now more particularly to the drawings, the structure at the base of the centrifuge bowl illustrated therein comprises a bowl bottom 10 having a downwardly depending boss I I, which is provided witha vertical bore 1l-2 through which the liquid is fed to the centrifuge bowl. The bowl .shell 13 is threadedly connected to an .outer .annular ring M on the .bowlwbottom l0 and is adapted to rotate with bottom H) at relatively highspeeds. ,Acup-shaped member I5 is mounted in alignment with bore l2 and compressed tightly against a counterfacedsurface it of -bottom iii through an annular gasket -lzl. Retainer 18 is adapted .to clamp member tightly against the gasket by means of threads I 9.
In order to bring the liquid up to the speed of the bowl as rapidly as possible after the liquid is fed into the bowl, a plurality of vanes 01' wings 21B are positioned in axial alignmentwith the bore 1:2 and retained in the hollow portion -of .cup 115. The wings'ar-e prevented from rotating relatively with respect to the bowl'gas'sembly by means of a pin 21 pressed into the bore-ofcup 45.
The upper :portion 15a .of the cup I5 is of reduced diameter and is provided with a plurality .of radial ports 22 which terminate :at their outer ends in an annular groove 23 adapted to receive a flexible ring 24 which may be made of rubber or similar material. The concave curvature of groove 23 may pref-erably'be of the same radius as the cross-sectionalcurvature of ring 24 shown clearly in Figs. 1 and 2. It will be understood that the cross-section of one side of ring member 24 is circular as shown in Fig. 2. However, any
other cross-sectional shape may be employed, providing satisfactory sealing between ports 22 and the ring 24 is obtained.
The bore 25 of retainer 18 is greater than the diameter of the upper portion la to provide ample passage for inflowing liquid. Retainer I8 is also provided with an annular internal groove 26 which is in registry with the ports 22, 22. Slots 27, 21 in-retainer [8 enable it to be quickly assembled or dis-assembled by means of a suitable tool.
Referring now to Fig. 4, the modified embodiment shown therein may be substituted in its entirety for cup [5 and retainer I8, together with the valve '24. Valve body member 39 is provided with external threads 3! adapted to cooperate with threads [9 and thereby to provide a tight seal with bowl bottom Ill through gasket l1. Body 30 is likewise provided with a plurality of radially extending ports 32 which connect the bore 33 of body 30 with feed passage l2. The upper portion of body 32 has a slight overhang at 39' to which a plurality of flat springs 34, 34 are attached in a downwardly depending position by means of screws 35, 35. The lower end of each spring 34 carries a plug or stopper 36 each of which is adapted to register with an individual port 32. The material used in the plugs will depend upon the particular liquid being centrifuged and may be rubber, leather, or some form of synthetic plastic which will be impervious to any chemical action likely to take place. The top of body 33 is drilled at 3T, 31 to accept a suitable tool for removing or tightening the member 30 against bowl bottom Hi.
It will be understood that the elasticity of springs 34 is so calculated that ports 32 will be closed by stoppers 36 at all speeds substantially below normal operating speed of the bowl.
In operation, the flexible ring 24 or the individual springs 34 tightly seal ports 22 or 32 as the case may be, as shown in Figs. 1 and 4. This prevents any flow of liquid through the ports when the bowl is stationary or substantially below normal operating speed. As the bowl is brought up to speed, centrifugal force expands the ring or distends springs 34 to open ports 22 and 32. In the case of the flexible ring, it will be observed that centrifugal force causes the ring to expand radially so that it fits in the annular seat 26. Likewise in the case of the spring 34, outward radial movement thereof is limited by the inside wall of bowl shell 13 as shown in Fig. 4. The speed at which the ports 22 and 23 are opened depends upon the physical characteristics of the ring or the springs, as the case may be. It is only necessary that the ports be closed when the vertical component or" the force acting on the liquid in the bowl due to gravity, bears such a relation to the horizontal component due to centrifugal force, that the liquid in the bowl will recede sufiiciently from the norm-a1 operating position (in which the liquid assumes the shape of an annulus around'the' inner periphery of the bowl and having a nearly vertical inner wall spaced radially outwardly away from ports 22 and 32) to come in contact with the check valve assembly.
It will thus be apparent that I have provided an extremely eflicient automatic valve for a centrifuge, which absolutely prevents any undesired return of liquid from the bowl when it is station- 2,635,617 if' r ary or when it is slowed down. All the parts of the valve assembly are likewise simple and easy to manufacture. The flexing of the rubber O ring is the only movement of the valve in this embodiment and there is no metal-to-metal contact likely to wear and cause leakage.
Having thus described my invention, I claim:
1. A centrifugal valve assembly comprising a rotating member, a radially extending port in said member adapted to provide fluid passage through said member, a resilient valve member mounted at the radially outward extremity of said port and adapted to close said port, a retaining surface rotatable with the rotating member in radial outward spaced relation to the valve member, and a fluid passage between the retaining surface and the port, the retaining surface, fluid passage and valve member being so arranged that when the rotating member is stationary the valve member is resiliently pressed onto the terminus of the port to close said port, but when the member rotates at a relatively high speed centrifugal force causes the valve member to move radially outward to be held in a predetermined open position by the retaining surface, to provide fluid communication through the passage and the port.
2. A centrifugal valve assembly comprising a rotating member, a plurality of radially extending ports in said member adapted to provide fluid passage through said member, a resilient ring positioned to surround and close the radially outward termini of said ports, an annular retaining member rotatable with the rotating member, an internal wall on said retaining member defining an annular groove in registry with the outer termini of the ports in the rotating member and in radial outward spaced relation thereto, and a fluid passage between the rotating member and the retaining member, the retaining member, resilient ring and fluid passage being so arranged that when the rotating member is stationary the ring is resiliently pressed onto the terminus of the ports to close said ports, but when the member rotates at a relatively high speed centrifugal force causes the resilient ring to move radially outward to be held in a predetermined open position by the retaining member, to provide fluid communication through the passage and the ports.
3. Apparatus in accordance with claim 2, in which the rotating member is provided with an annular groove adapted to receive the resilient ring.
4. Apparatus in accordance with claim 1, in which the resilient valve member comprises a flat spring mounted on said rotating member, and a plug on said spring adapted to register with said port.
RAYMOND H. CONDELL.
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|U.S. Classification||137/56, 494/38, 494/4, 494/65|