US3160589A

US3160589A - Centrifuge having automatic means for controlling peripheral openings

Info

Publication number: US3160589A
Application number: US262489A
Authority: US
Inventors: Lawrence H Stone
Original assignee: Pennsalt Chemical Corp
Current assignee: Pennwalt Corp
Priority date: 1963-03-04
Filing date: 1963-03-04
Publication date: 1964-12-08
Anticipated expiration: 1981-12-08

Description

Dec. 8, 1964 L. H. STONE 3,160,589

CENTRIFUGE HAVING AUTOMATIC MEANS FOR CONTROLLING PERIPHERAL OPENINGS 2 Sheets-Sheet 1 Filed March 4, 1965 /lOO Currenf Source INVENTOR.

LAWRENCE STONE Sensmg SwiTch ATTOR NEY Solenoid Valve L. H. STONE 3,160,589 CENTRIFUGE HAVING AUTOMATIC MEANS FOR Dec. 8, 1964 CONTROLLING PERIPHERAL OPENINGS 2 Sheets-Sheet 2 Filed March 4, 1963 INVENTOR.

LAWRENCE H. STONE ATTORNEY United States Patent CENTRIFUGE HAVENG AUTQMATIC MEANS FGR QONTROLLING PERHPHERAL GRENH'JGS Lawrence H. Stone, Pararnus, Ni, assignor to Pennsalt Chemicals Corporation, a corporation ct Pennsylvania Filed Mar. 4, 15. 63, Ser. No. 262,489 6 Claims. (Ul. 233-) This invention relates to centrifuges. More specifically this invention relates to a centrifuge having improved means for controlling peripheral openings to discharge solids or other heavy components.

In the prior art it is well known to provide a centrifuge rotor with peripheral openings usually in the form of open nozzles for the purpose of discharging solids. Also well known are rotors having openings controlled by valves either manually operated through a control fluid or automatically operated upon accumulation of solids to a preset level. An example of the latter type of rotor is disclosed in the US. Patent 2,286,355 which issued June 16, 1942 on an application filed by Harold C. Fitzsimmons.

The present invention is an improvement on the device of the above-mentioned Fitzsimrnons patent in that it provides means by which the open-close cycle of a peripheral valve may be adjusted without stopping the centrifuge. Hence by the apparatus embodying the invention, the extent to which solids are permitted to accumulate for instance may be controlled While the machine is in operation.

Other features of the invention will be apparent upon reference to the drawings in the following description disclosing a preferred form of the invention.

FIGURE 1 is a fragmentary sectional View, partly in elevation, of an apparatus embodying the invention;

FIGURE 2 is a schematic circuit diagram of an apparatus embodying the invention;

FIGURE 3 is an enlarged fragmentary sectional View of the sensing switch means of an embodiment of the invention;

FIGURE 4 is an enlarged fragmentary sectional view taken on the line 4-4 of FIGURE 1; and

FIGURE 5 is a fragmentary sectional view taken on the line 5-5 of FIGURE 4.

Briefly, the invention is a centrifuge having at least one valved peripheral opening for occasional solids discharge, the valve having an electric control actuated by solids sensing means in the centrifuge.

Referring more specifically to the drawings, a centrifuge rotor embodying the invention is designated it} in FIG- URE 1. It comprises a rotor shell 12 mounted on a power spindle 14 which is driven by means not shown.

Disposed on a shoulder adjacent the upper end of the rotor shell 12 is the rotor cover 16 which is held down against the shoulder by a threaded ring element 18. The rotor shell 12 has discharge openings 20. A center tube 22 sits on a shoulder formed on the inner portion of the rotor shell 12 and features an outwardly and upwardly flaring skirt 24 formed with a feed opening 26. A stack 28 of frustc-conical discs rests on the skirt 24 and is held compressively between the skirt and the rotor cover 16. The feed pipe 3% delivers feed into the center tube.

The disc stack 28 is superposed by a conventional dividing cone having upward spacers to provide therebetween a passage 32 for heavy liquid discharge over a weir 34. The dividing cone is provided with a longitudinal tubular extension 36 for conducting light liquid discharge in the conventional manner.

Mounted for reciprocation between the rotor shell 12 and the skirt 24 is the valve element 38 which is formed with a leak opening 39. As is conventional the valve element is biased upwardly preferably by the presence of liquid in the chamber 49 which may be supplied through Patented Dec. 8, 1964 ice tube 42, pocket 44 in the rotor shell 12 and thin-bored passage 46. Drain 4S vents excess.

The valve element 38 may be moved downward to provide an opening below cover 1o by a flow of liquid into the chamber 5i; through tube 42, pocket 44 and passage 52. Downward movement of valve element 38 may be eifected when the liquid pressure force against the upward side of the element exceeds that on the lower side.

The cycle of flow of control liquid through the tube 42 is initiated by the electric switch 54 mounted on the inside of the cover 16 and the skirt 24. Leads 56 from the switch are connected respectively to slip rings 58 mounted on spacers 69 (FIGS. 4 and 5). The spacers permit passage of the heavy liquid discharge between the cover 16 and the rings. The rings 58 are engaged respec tively by contacts 62 mounted on a stationary bracket which may be supported on the under side of the light liquid collector as shown.

Referring to FIGURE 3, a fluid motor 64 operates to move the switch. It comprises a housing which consists of an end portion 66 and a base portion as to which the end portion 66 is secured. The base portion 68 has an annular extension 7% which lies adjacent but is suitably spaced by space 71 from the juncture of the walls of cover 16 and shrt 24. A piston 72 which is the moving member of the fluid motor is mounted for reciprocation in end portion 66 and has a stem '74 which extends therethrough.

The housing base 68 is provided with a lateral extension 76 through which liquid is passed from the main body of the rotor for actuating the fluid motor.

A bore 78 in extension 76 communicates with the space 71 through the passage provided by the annular flange 79. The bore 78 is in turn connected with a conduit 82 which extends downwardly and inwardly around the lower end of the stack 28 of discs and into an opening in the skirt 24. The inner end of the conduit 82 is connected to a member 84 which has a bore 86 communicating with the conduit 82 and also a channel 38 communicating with the inner end of bore 36. A second bore extends outwardly from the channel 88 and is connected to a second conduit 92 which is connected with a bore 94 in the lateral extension 76 of the housing base 63.

The bore 94 communicates with the space as between the inside portion 64 of the housing and the outer surface of the piston 72. The inner surface of the piston 72 communicates with the space 71 of the rotor through the hollow interior of the guide 98 which is a stationary member along which the piston reciprocates, rubber rings acting as a seal. The space as is also in communication to the outside of the rotor through a leak passage 1%.

Mounted over the end portion 65 is the switch cap 192 which carries a contact button 134- and a spring contact 106 to which the leads 56 are attached, respectively.

The contact button 134 and the spring contact 1&6 comprise the electrical elements of the sensing switch shown in circuit (FIG. 2) with a timer and solenoid valve in the control liquid, such as line 52. Under the arrangement shown after the switch has been closed for a period depending on the setting of the timer the solenoid valve will be opened to effect the opening of the valve element 38.

The operation will be understood by further reference to FlGURE 3. As the centrifuge it; is brought up to speed the piston 72 is thrown outward under centrifugal force. As the rotor is filled with feed mixture, some will pass inward through the opening in extension 76 and in through the guide 98 to urge the piston inwardly. Liquid will also pass inward through passage '78, conduit 82 to channel 88 and outward through conduit 92, passage 94 to chamber 96 to urge the piston outward. The force on the opposite sides of the piston '72 being equal,

the weight of the piston urges it to its outward position shown. When solids accumulate to cover the opening between the annular extension 70 and passage 78 travel of liquid through

passages

82 and 92 to chamber 96 ceases and the chamber is evacuated as its liquid drains through passage 100. This leaves liquid acting on the outer face of piston 72 against the weight of the piston only and the result is the inward movement of the piston closing the contacts 104 and 106. This, through the circuit shown in FIGURE 2, commences operation of the timer and eventually opens the solenoid valve to lower element 38 and permits solids to escape through the passage 20. When the evacuation of solids from the area around the opening between the annular extension 70 and passage 78 once more permits passage of liquid to chamber 96, the piston will move outward, opening the contacts to close the solenoid valve. The liquid draining through the passage 39 removes the downward force on element 33 which raises to close the rotor again.

It should be understood that the above operation including the closing of the peripheral opening after the solids are discharged is based on the mode of use in which the feed rate to the centrifuge is greater than the rate of discharge through the openings 20. In the situation in which such discharge exceeds the feed rate, the level of liquid in the bowl will move outward when the openings 20 are opened and after solids discharge there will be no pressure available to drive liquid in through passage 78 to channel 88 and ultimately to chamber 96 to move the piston 72 outward to open the contacts as described above. Instead the piston will remain in its inward position and the contacts closed until the liquid level moves outward of the outer face of piston 72. To assure control in such a situation additional adjustable timing means may be provided, for instance to break the circuit shown in FIGURE 2 after the elapse of a preset time, and keep the circuit open until the liquid in the bowl has returned to its inward level, thereby opening contacts 104, 106.

From the above description it will be apparent to one skilled in the art that Ihave developed means for controlling the discharge of solids from a centrifuge rotor in a way which may be adjusted while the rotor is in operation to control the residence time of solids in the bowl and hence the degree of compaction of solids. This improvement will be of benefit to those, for instance, in the vegetable oil industry wherein in Winterizing it is essential that the stearine solids remain in the bowl sufficiently long to force out entrained oil portions, but not so long that they affect the clarity of the liquid discharge.

Variations in structure are possible. For instance, control of the amount of time that the rotor remains open may be achieved by means for delaying-the closing of the solenoid valve. Further, if desired and permitted, one of the contacts 104 and 106 may be grounded to the frame of the machine and one of the leads 56 and rings may be dispensed with, the machine itself acting as a conductor. Additionally skirt 24 may be dispensed with and the valve element 38 may constitute the bottom wall of the bowl biased downward by liquid in the bowl. In such an arrangement the chamber 40 may be pressurized with control liquid as known in the art to keep the element up against its seat on cover 16 closing the bowl until an opening is desired. These and other variations are deemed to be within the competence of one skilled in the art.

Therefore, having particularly described my invention, it is to be understood that the description is by way of illustration and that changes, omissions, additions, substitutions and/ 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 combination,

(a) a centrifuge having a centrifuging zone having at least one peripheral opening for the discharge of solids from said centrifuging zone,

(b) an hydraulically operated valve element disposed in the centrifuge and controlling said peripheral opening, the valve element having an hydraulic power chamber,

(c) conduit means for supplying a control fluid to said power chamber to drive the valve element in one direction,

(d) electrically actuatable valve means in said conduit means to control the flow of control fluid to the power chamber,

(e) means in the centrifuge biasing the valve element in the opposite direction,

(f) fluid motor means in said centrifuging zone,

(g) a piston constituting part of the fluid motor means and having two sides, one side being exposed to the inside of the motor means, and the other side being exposed to the centrifuging zone,

(1:) passage means in said centrifuge zone having an inlet and connected to the inside of the fluid motor,

(1) outlet means from the inside of the fluid motor to the outside of the centrifuging zone, and

(j) electric switch means in said centrifuging zone adjacent said piston and adapted to be operated thereby, said switch means being electrically connected to said electrically actuatable valve means to corn trol it,

whereby when solids accumulate in said zone to block said inlet a portion of the liquid contents of said fluid motor will drain through the outlet means to reduce pressure in the motor so that the piston moves to operate the switch means which in turn operates the electrically actuatable valve means controlling flow of control fluid to the power chamber to open the valve element controlling the peripheral opening to permit solids to discharge therethrough.

2. The combination of claim 1 wherein adjustable time delay means are in circuit with the electric switch means to delay opening of the valve element for a preset period after the electric switch means is operated by said movement of the piston.

3. The combination of claim 1 wherein the electric switch means is electrically connected to said electrically actuatable valve means through at least one slip ring mounted on said centrifuge.

4. The combination of claim 1 wherein the valve element comprises an annular element positioned about the axis of the centrifuge and adapted to move in axial directions.

5 The combination of claim 1 wherein adjustable electric timing means are provided in circuit with the electric switch means to assure subsequent closing of the valve element.

6. The combination of claim 1 wherein said passage means includes portions extending in directions both inward of the centrifuging zone and outward of the zone.

References Cited by the Examiner UNITED STATES PATENTS 802,473 10/05 Raasloft 233-20 X 1,375,506 4/21 Gray 233-20 X 2,113,175 4/38 Elrod 233-20 2,286,355 6/42 Fitzsimmons 233-46 X 2,378,778 6/45 Lindglen .et a1. 233-20 2,501,179 3/50 Komline 233-20 2,723,799 11/55 Sharples 233-20 2,820,589 1/58 Fitzsimmons 233-20 2,955,754 10/60 Nyrop 233-20 (Qther references on following page) FOREIGN PATENTS Great Britain. Great Britain. Germany. Netherlands.

6 OTHER REFERENCES GEORGE D. MITCHELL, Primary Examiner. ROBERT F. BURNETT, Examiner.

Claims

1. IN COMBINATION, (A) A CENTRIFUGE HAVING A CENTRIFUGING ZONE HAVING AT LEAST ONE PERIPHERAL OPENING FOR THE DISCHARGE OF SOLIDS FROM SAID CENTRIFUGING ZONE, (B) AN HYDRAULICALLY OPERATED VALVE ELEMENT DISPOSED IN THE CENTRIFUGE AND CONTROLLING SAID PERIPHERAL OPENING, THE VALVE ELEMENT HAVING AN HYDRAULIC POWER CHAMBER, (C) CONDUIT MEANS FOR SUPPLYING A CONTROL FLUID TO SAID POWER CHAMGER TO DRIVE THE VALVE ELEMENT IN ONE DIRECTION, (D) ELECTRICALLY ACTUATABLE VALVE MEANS IN SAID CONDUIT MEANS TO CONTROL THE FLOW OF CONTROL FLUID TO THE POWER CHAMBER, (E) MEANS IN THE CENTRIFUGE BIASING THE VALVE ELEMENT IN THE OPPOSITE DIRECTION, (F) FLUID MOTOR MEANS IN SAID CENTRIFUGING ZONE, (G) A PISTON CONSTITUTING PART OF THE FLUID MOTOR MEANS AND HAVING TWO SIDES, ONE SIDE BEING EXPOSED TO THE INSIDE OF THE MOTOR MEANS, AND THE OTHER SIDE BEING EXPOSED TO THE CENTRIFUGING ZONE, (H) PASSAGE MEANS IN SAID CENTRIFUGE ZONE HAVING AN INLET AND CONNECTED TO THE INSIDE OF THE FLUID MOTOR, (I) OUTLET MEANS FROM THE INSIDE OF THE FLUID MOTOR TO THE OUTSIDE OF THE CENTRIFUGING ZONE, AND (J) ELECTRIC SWITCH MEANS IN SAID CENTRIFUGING ZONE ADJACENT SAID PISTON AND ADAPTED TO BE OPERATED THEREBY, SAID SWITCH MEANS BEING ELECTRICALLY CONNECTED TO SAID ELECTRICALLY ACTUATABLE VALVE MEANS TO CONTROL IT, WHEREBY WHEN SOLIDS ACCUMULATE IN SAID ZONE TO BLOCK SAID INLET A PORTION OF THE LIQUID CONTENTS OF SAID FLUID MOTOR WILL DRAIN THROUGH THE OUTLET MEANS TO REDUCE PRESSURE IN THE MOTOR SO THAT THE PISTON MOVES TO OPERATE THE SWITCH MEANS WHICH IN TURN OPERATES THE ELECTRICALLY ACTUATABLE VALVE MEANS CONTROLLING FLOW OF CONTROL FLUID TO THE POWER CHAMBER TO OPEN THE VALVE ELEMENT CONTROLLING THE PERIPHERAL OPENING TO PERMIT SOLIDS TO DISCHARGE THERETHROUGH.