US2608344A - Centrifuge construction with semiautomatic controls for a movable vacuum chamber - Google Patents

Description

E. G. PICKELS 26, CENTRIFUGE CONSTRUCTION WITH SEMIAUTOMATIC 2,608,344

CONTROLS FOR A MOVABLE VACUUM CHAMBER 2 SHEETSSHEET 1 Filed May 17, 1948 minim m INVENTOR Y E. 6 /lCkB/S a ATTORNEYS Aug. 26, 1952 g; G. PICKELS CENTRIFUGE CONSTRUCTION WITH SEMIAUTOMATIC CONTROLS FOR A MOVABLE VACUUM CHAMBER 2 sums-swam 2 Filed May 17, 1948 'FIELE- INVENTQR 1 (1%. P/cke/E ATTORNEZYE Patented Aug. 26, 1952 Edward G. Pickels, Palo Alto, Calif., assignor to A MOVABLE Specialized Instruments Corporation, Belmont, Calif., a corporation'of California Application May 17, 1948, Serial No. 27,549

I V. I 1 .1 'l l V This invention relates generally to centrifuge apparatus, particularly apparatus in: which the centrifugerrotor is .adapted to ,be enclosed in an.

evacuated chamber during its operation.

It. is anobjec't of the present invention to provide a centrifuge apparatus. having novel means for moving the vacuum chamber between open and closed positions with respect to the centrifuge rotor. r l a Another object of the invention is to provide centrifuge apparatus of the above character in which the means for moving the vacuum chamber facilities obtaininga good vacuum tight seal between the main body of the vacuum chamber and its cooperating cover.

Another object of the invention is to provide centrifuge apparatus of the above character in which the means for moving the vacuum chamber'issemi-aut'omatic, inthat movement to open orzclosed positions is instituted manually and controlled automatically to arrest movement whenithe chamber reaches normal full open or closed positions.

.qAnother objectof the invention is to provide a.,centrifuge.of the above character having certain safety features, including protection against starting the rotor when the'lvacuu'm chamber is open, and protection againstaniattempt. to open the chamber before breaking the vacuum within the same; w

' Further 1 objects of .theiinvention will. appear tailw in tconjunctio'n with. the accompanying drawings". 1

.:R.eferringtothedrawing: t-z-Eigurecl is asideyelevational view in section illustrating j' centrifuge apparatus incorporating. theIpresent invention. fl-jFigure 2. is a cross-sectional detail taken along theline2+2iof-Figure1J S r Figure13'isra cross-sectional detail taken along the-line 3 -3 of Figure 1. i

"Figure 4 is a CI'OSSSECtiOIlEL]. detail largedscale taken along the line 4-4 of Figurel.

'igure'5 is across-sectional view taken along the line 55 of Figure 1.

'Figure 6 is a circuit diagram illustrating the various circuit connections to the driving motors. The centrifugeas illustrated in the drawings consists generally of an outer housing In which serves to enclose the working parts The rotor this disposed. within the housing and is operatively attachedto the vertical shaft I2, bythe coupling l3. A plate [4 extends above the rotor, and as will be presentlyexplained, this plate forms. a cover. for thevacuum chamber [6, when thelatte'r' isin operative or closed position surrounding th'rotor. Above the plate M there is on an en-.

a 5 Claims. 01-233 1) I 2 an electrical driving .therotor II at a. desired selected speed.

The .vacuum chamber IE inthis instance'inshaped side walls 2!.

centrifuge rotor.

taneously' herewith, and entitled Centrifuge Construction.

Within the member 22 it is convenient to pro vide ametal shell 23, which is surrounded by a metaltube 24 through which a cooling fluid can Novel elevating means is provided in connec-r tion with the vacuum chamber 16, whereby this chamber can be moved from the open position, illustrated in Figure l,' to a closed position in. which it surroundsthe rotor II and is sealed" with respect to the cover plate 14. The elevat-i ing means in this instance consists of three ,ver-. tically disposed lift rods 26, which extend through openings 21 and 28 in plates l4 and I9. Each rod has a threaded portion 29 engaged by anuti 3|, These nuts are non-rotatable with respect. to the plate It, whereby when therods are all rotated the nuts together with plate 19 move. 5 upwardly or downwardly, depending upontheidiiw 'rection of. rotation. One nut can be fixed tcfplate 19 as indicated by screw 20, leaving the other; nuts free for limited self-aligning movement rel-y ative to the plate. t

The lower ends of rods 26 are engaged by the thrust bearing assemblies 33, whichin turn are movably retained within the sockets 34. These,

sockets can be short sections of metal tubing attachedatatheir lower ends tothe bottom wall Within each socket thereis Fixed to the lower end-of each rod 26 there is a vsprocket 31, and the sprockets of alllthree rods are connected together by the commonchain drive 38. The chain is maintained taut by means of an idler sprocket 39 which is;-ca1';

ried bythe bracket 4!. The upper ends of the rods 26 are provided with enlarged heads 42,;and one rod, as for example the right hand rod, apri. pearing in Figure 1. is attached to an extenrrs.

motor 11, and adjustable. ratio. drive gearing 18, .to turn the shaft 12 and;

When the 5 plus the weight of the lift rods.

sion shaft 43 which extends upwardly'through the partition wall 44'. The upper end of shaft 43 has an operative connection with a reversible electric motor 46, as through speed reducing gearing including for example motor shaft pin.-

ion 41, gear and pinion 48 .and'4'9, andgear I' vacuum chamber, and for this condition the weight of the moving parts of the chamber I6, and the rods 26, is carried by the spring 36.

The motor 46 is connected to an electrical circuit which includes both manual and automatically operated switches, as will be presently ex-' plained. Switches- I, 2 and 3 of this circuit are carried by a. suitable support bracket 53, and are. all-operatively associated with a common lever 54. 'One endof this lever is pivoted at 55 to a side Wall ofthe housing, and'the other end is urged downwardly by the tension spring 56. A set screw. 57 forms an adjustable abutment with theupper end of the extension-shaft 43, and adjustable'setscrews58p59 and 6| form operative connections with the operating members of the respective switches I, 2 and 3. An additional control switch 4 is mountedupon the housing.

and is positioned to have its operating member engaged and moved by contact with the bottom plate I9 of the vacuum chamber, when the vacuum chamber reaches the lower limit of its travel.

The circuit diagram for the motor 46 is shown in Figure 6. The motor 46 is one of the reversible type having four points of connection to the same. Conductor 62 connects the current supply line L-I to one of the terminals of motor 46, and also to one pole 64 of the three pole double throw switch 63. This switch is manually operated to one or the other of its two operating positions for the purpose of elevating or lowering the vacuum chamber. To facilitate describing the electrical connections to switch 63,

the-poles of this switch have been designated at.

64; 65 and 66, the contacts for one side as 61, 68' and 69, and the contacts on the other side as II, 1 2" and 13. Contacts 61 and 12 are connected-together by conductor 14, and conductor 15 connects these contacts to another terminal of-motor 46. Switch poles 65 and 66 are connected' together, and are also connected by conductor 16 to. another terminal of motor 46. Signal lamp His connected between pole 66 and line L-I. Switch contacts 66 and H are connected together by conductor 18 and are connected-to another terminal of motor 46 by conduotor I9. Contact 69 of the switch 63 is connectedby conductor 8| to one side of the control'switch I, and the other side of this control switch is connected by conductor 82 to one side of control switch 3.- The other side of switch 3' is connected by conductor 83 to the current supis such. "that when the vacuum; chamber has reachedits normal closed position, the-switch I is moved to open position. Likewise when the vacuum chamber is moved toward open position switch I closes after. such movement has been initiated, and when the chamber has reached full open position switch 4 is engaged to cause it to be opened. Thus when the main reversing switch 63 is in its upper position (as viewed in Figure 6), opening of switch I de-energizes the motor to arrest upward movement of the vacuum chamber. When the main reversing switch is in down position, opening of the switch 4 likewise de-energizes the motor to arrest downward movement of the vacuum chamberias it reaches its lowermost position.

Opening or closing of" the vacuum .chambertis;

initiated by manual operation ofathetswitch- 63'.

As connected in Figure '6' its-upper positionrreperesents the position to which it is moved when it is desired to elevate and close, the: chamber,. and when moved to its lower position the-chamber is caused to open. Normally switch 63 is not. moved until one desires to move the: vacuum;

chamber to another position, and therefore after a normal opening movement of the chamber. switch 63 would be left with its. poles in lowermost position. It will .be noted that for the'condition illustrated in Figure 6, switch 2 isopen; and therefore it would be. impossible for the :op--' erator to supply current to the driving motor. of the rotor I1.

Assuming that theo-peratorwishes to :close the I chamber for carrying out a centrifugingsopera tion, switch 63' is thrown'to close'upon contacts; 6! to 69 inclusive,.and this serves to supply cur-- rent tothe motor 46 wherebythis motor is. driven; in a direction to raise or elevate :the'vacuum chamber. After initial upward movement switch 4 closes.

the sealing gasket. provided in plate l4, continued rotation of the rods .26 causes them to move: downwardly with respect to the plate I4. (but; without direct engagement with the same), andthis downward movement causes switch I'tob'e opened, whereby the current. supply. fromline L-2 to the motor 46 is interrupted, and themotor stopped in this position. At the same time switch 2 is closed, thus making it possible for-theroperator to :operate the rotor driven motor- IT by closing switch 86. The slight amount of further.

downward movement of the rods 26 after the vacuum chamber comes to a stationary position" in engagement with plate I4, is desirable because such movement is used for operation of the-switch I, and in addition it insures gOOd sealing engagement between the top edge of the vacuum chamber and the cooperating sealing gasket carried by the plate I4, eventhough the'top edge may not be in a plane which is exactly parallel to theplane of 'theplate I4, at the time of engagement with the cooperating gasket. movement of the rods 26 causes an-increased spring tension against the rods, to thereby apply. closing force to the chamber Walls which is dis- Wherethe heads 42 may for example be spaced from plate;

trib uted entirely about the same.

I4 about /4 inch for open positionof the chamber, for full closed /311'101'1.

The final downward Y position they maybe spaced After a centrifuging operation, when it is desired to lower the vacuum chamber, air is first admitted to the vacuum chamber to break the vacuum, and then switch 63 is thrown to its lower position whereby the circuit to the motor 46 is closed and this motor driven in a reverse direction to lower the chamber. Immediately prior to lowering of the chamber the heads 42 rise to their normal positions with respect to plate I4, thus closing switch I and opening switch 2. In the event the operator should neglect to first break the vacuum to the vacuum chamber, before attempting to lower the vacuum chamber to open position, the vacuum chamber would be held in closed position by virtue of atmospheric pressure, and rods 26 would be moved upwardly a limited distance under the urge of the compression springs 36. Such movement (which carries heads 42 to a distance from plate 14 beyond the position which they occupy when the vacuum chamber is open) when transmitted to the lever 54 causes opening of normally closed switch 3, thus interrupting current supply to the motor 46. This indicates to the operator that the vacuum has not been broken. When the operator proceeds t properly break the vacuum in the chamber, rods 26 will again assume their normal positions to effect closing of switch 3, thus permitting the vacuum chamber to be moved toward open position as normal.

It will be evident from the foregoing that my apparatus has many featurees of safety, particularly in that it avoids operation of the rotor until the vacuum chamber is in full closed position,

and it prevents injury to the apparatus in the event one attempts to move the vacuum chamber to open position without properly breaking the vacuum. The action of the springs 36 is utilized in effecting operation of certain of the control switches as previously described, and they aid in applying properly distributed pressure to the vacuum chamber, in urging the same toward closed sealed position. The mechanism used for raising and lowering the vacuum chamber is relatively simple and is well adapted for operation bya reversible electrical motor.

I claim:

1. In centrifuge apparatus, a centrifuge rotor, a vacuum chamber movable between closed and open positions with respect to the rotor, a cover for the vacuum chamber against which the chamher is adapted to seal when in closed position, electric motor means for moving the vacuum chamber between closed and open positions, and means for automatically deenergizing said motor means in the event the vacuum in the chamber is not broken before endeavoring to move the same to open position.

2. In centrifuge apparatus, a centrifuge rotor, a motor serving to drive the rotor, a vacuum chamber adapted to be moved between closed and open positions with respect to th rotor, motive means for moving'the vacuum chamber between closed and open positions, an electrical energizing circuit for the motor which drives the rotor, means including a switch serving to control said energizing circuit, and means for causing said switch to be opened responsive to movement of the vacuum chamber from closed position,

3. In centrifuge apparatus, a rotor mounted to turn about a vertical axis, an electric motor connected to drive the rotor, an energizing circuit for said motor, a vacuum chamber for the rotor,

rr I.

a cover for the vacuum chamber mounted above the rotor and serving to seal with respect to the vacuum chamber, means for raising the chamber to a position to enclose the rotor and to seal with respect to said cover and for lowering the chamber to a position to permit access to the rotor, said last means including an electric motor and an energizing circuit for the same, a switch in the energizing circuit for the rotor motor and serving to deenergize said circuit when the switch is opened, means serving to cause closure of said switch only when said chamber is in sealed relation with respect to said cover and to effect opening of the same when the chamber is moved from closed position, a switch in the energizing circuit of the motor which drives the means for raising or lowering the vacuum chamber, said last switch when opened serving to deenergize said last named motor, and means for causing automatic opening of said last named switch responsive to initial energization of said motor to lower said vacuum chamber when a condition of vacuum exists within the same.

4. In a centrifuge construction, a centrifuge rotor, a drive means for the rotor, .a stationary horizontal cover plate disposed above the rotor,

a vacuum chamber for the rotor and adapted to enclose the rotor in sealing relation with the cover, motive means for raising or lowering said chamber relative to the rotor and said cover plate, said last named means including a plurality of vertical threaded rods, motive means for turning said rods in unison, members serving to carry the vacuum chamber and having threaded engagement with said rods, and spring means serving to yieldably support said rods.

5. In a centrifuge construction, a centrifuge rotor, a drive means for the rotor, a stationary horizontal cover plate disposed above the rotor, a vacuum chamber for the rotor and adapted to enclose the rotor in sealing relation with the cover, motive means for raisin or lowering said chamber relative to th rotor and said cover plate, said last named means including a plurality of vertical threaded rods, motive means for turning said rods in unison, and nuts serving to carry the vacuum chamber and having threaded engagement with said rods, only one of said nuts being fixed relative to the chamber and the other nuts having nonrotatable engagement with the chamber.

EDWARD G. PICKELS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 413-416, December 1938.

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