US3313139A - Precision centrifuge - Google Patents

Precision centrifuge Download PDF

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Publication number
US3313139A
US3313139A US406833A US40683364A US3313139A US 3313139 A US3313139 A US 3313139A US 406833 A US406833 A US 406833A US 40683364 A US40683364 A US 40683364A US 3313139 A US3313139 A US 3313139A
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United States
Prior art keywords
centrifuge
shaft
vertical shaft
frame structure
precision
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Expired - Lifetime
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US406833A
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English (en)
Inventor
Caumartin Yves
Habermann Helmut
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Etat Francais
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Etat Francais
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Publication date
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Publication of US3313139A publication Critical patent/US3313139A/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00—Bearings not otherwise provided for
    • F16C32/06—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings
    • F16C32/0603—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings supported by a gas cushion, e.g. an air cushion
    • F16C32/0614—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings supported by a gas cushion, e.g. an air cushion the gas being supplied under pressure, e.g. aerostatic bearings
    • F16C32/0625—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings supported by a gas cushion, e.g. an air cushion the gas being supplied under pressure, e.g. aerostatic bearings via supply slits
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B13/00—Control arrangements specially designed for centrifuges; Programme control of centrifuges
    • B04B13/003—Rotor identification systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B5/00—Other centrifuges
    • B04B5/04—Radial chamber apparatus for separating predominantly liquid mixtures, e.g. butyrometers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B9/00—Drives specially designed for centrifuges; Arrangement or disposition of transmission gearing; Suspending or balancing rotary bowls
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00—Bearings not otherwise provided for
    • F16C32/06—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings
    • F16C32/0662—Details of hydrostatic bearings independent of fluid supply or direction of load
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00—Bearings not otherwise provided for
    • F16C32/06—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings
    • F16C32/0681—Construction or mounting aspects of hydrostatic bearings, for exclusively rotary movement, related to the direction of load
    • F16C32/0696—Construction or mounting aspects of hydrostatic bearings, for exclusively rotary movement, related to the direction of load for both radial and axial load
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P21/00—Testing or calibrating of apparatus or devices covered by the preceding groups
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P1/00—Arrangements for starting electric motors or dynamo-electric converters
    • H02P1/16—Arrangements for starting electric motors or dynamo-electric converters for starting dynamo-electric motors or dynamo-electric converters
    • H02P1/166—Driving load with high inertia

Definitions

  • the precision centrifuge according to this invention comprising a vertical shaft rotatably driven by an electromotor is characterized in that this shaft has its lower end supported by a hydraulic footstep bearing having a very low friction torque and its upper portion mounted in an air-bearing having practically zero friction torque, and that the rotary members of the centrifuge are housed inside a fairing or casing of revolution rigid with said shaft.
  • the precision centrifuge according to this invention is advantageous in that the variations in reaction torque are practically eliminated so that a predetermined velocity of rotation may be obtained with a high degree of precision.
  • the centrifuge may be operated in a conventional closed room.
  • FIGURE 1 is a vertical section showing the general structure of the precision centrifuge of this invention
  • FIGURE 2 is a longitudinal section showing on a larger scale the hydraulic footstep bearing of the vertical shaft of the precision centrifuge;
  • FIGURE 3 is a longitudinal section showing the airbearing provided at the upper end of the centrifuge
  • FIGURE 4 is a longitudinal section showing a component element of the rotary electric collector ring
  • FIGURE 5 is a block diagram showing the system for controlling the centrifuge.
  • the precision centrifuge comprises essentially a vertical shaft 1 carrying two opposite radial arms 2, 3.
  • One of these arms, for instance 2 carries on its outer end a measuring plate on which the apparatus A to be tested is secured.
  • the apparatus being tested is an accelerometer.
  • the opposite arm 3 carries on its outer end a balance weight B.
  • the shaft 1 has its lower end supported by a hydraulic footstep or like bearing designated in general by the reference numeral 4, and its upper end mounted in an air bearing 5.
  • the shaft 1 of the centrifuge illustrated is coupled in line with the armature 6 of an electromotor 7.
  • This motor 7 and the air bearing 5 are supported by 3,313,139 Patented Apr. 11, 1967 ice a base plate 8 mounted on the upper portion of a triangular frame structure 9 isolate-d from external vibration.
  • the hydraulic footstep or like bearing 4 is supported by a concrete slab 11 isolated from external vibration likely to be transmitted through the soil.
  • the shaft 1 is balanced by means of weight 12 which are eight in number in this example and slidably mounted respectively on radial rods 13 rigid with shaft 1 and locked in adequate positions along said rods. These radial rods 13 are disposed in two separate horizontal planes containing each four rods.
  • the assembly comprising the two lateral arms 2, 3 and rods 13 carrying the balance Weights 12 is housed inside a casing or fairing of revolution 14 comprising a cylindrical central portion having an upper extension and a lower extension in the form of conical shells.
  • a casing or fairing of revolution 14 comprising a cylindrical central portion having an upper extension and a lower extension in the form of conical shells.
  • a first rough adjustment is effected by simply moving the air bearing 5 relative to its support 8 by'using a micrometric screw 15.v
  • bracing rods or cables 17 are acted upon, these bracing rods or cables 17 being fastened on the surrounding walls 18 of the room through adequate tension springs 19.
  • These bracing rods or cables 17 may be three or more in number. producing an elastic deformation of the frame structure 9, whereby a precision of the order of 1:100,000 radians may be obtained as far as the verticality of shaft 1 is concerned.
  • the shaft 1 is disclosed as having its lower end supported by a hydraulic footstep bearing or like device 4. This hearing will now be described more in detail with specific reference to FIGURE 2.
  • the lower portion of shaft 1 is formed with a central blind bore 1a engaged by a cylindrical central upstanding flanged pintle 21 carried by a base plate 22 of very hard material, a ball 23 being interposed between these members 21 and 22.
  • the cylindrical intermediate pintle 21 has a longitudinal passage or duct 24 formed therein which communicates at its lower end with a radial duct 25 connected to a source ofoil under pressure 26 (FIG- URE 1).
  • the longitudinal duct 24 opens at its upper end into the bottom of said blind bore 1a and is provided with a pair of spaced branch radial ducts 27 opening in turn into the lateral surface of the cylindrical pintle 21.
  • the cylindrical skirt 1b formed at the lower end of shaft 1 by the blind bore 1a has at least one longitudinal bore 20 formed therein which opens into the lower end face of the shaft 1 and communicates with said blind bore 1a through a small orifice 28 at its upper end and also through one or more intermediate transverse ducts 29.
  • the shaft 1 is supported by the upper face of pintle 21 through the medium of an oil film.
  • another oil film is interposed laterally between said pintle 21 and the skirt 1b of shaft 1.
  • FIGURE 3 describe in detail the air bearing designated in general by the reference numeral 5 in FIGURE 1.
  • This air bear ing consists of two annular members 31, 32 assembled by means of screws 33 and receiving the shaft l ther ethrough. Formed between these members is an annular Their tension is used for.
  • the shaft 1 is properly centered and the resistance caused by" 3 chamber 34 connected through a pipe 35 to a source of compressed air shown at 36 in FIGURE 1.
  • the chamber 34 communicates through an annular slot 37 with a narrow, sleeve-like space left between shaft 1 and,
  • the air bearing permits like-wise of minimizing friction losses.
  • T-he circuits of the electrical apparatus A rigid with the arm 2 of the centrifuge are connected to a rotary, mercury-type electric collector shown at 41 in FIGURE 1.
  • This collector consists of a plurality of superposed elements of which one is shown in detail in FIGURE 4.
  • This elementary collector comprises a stationary annul'ar trough 42 filled with mercury 43 and disposed coaxially to the shaft 1.
  • Partially immersed in the mercury 43 is thev cylindrical depending skirt of a conducting inverted cup 44 solid with shaft 1, an insulating sleeve or socket 45 being interposed between the cup 44 and shaft 1.
  • the mercury 43 is electrically connected through a conduct-or 46 with fixed control apparatus and the conducting cup 44 is connected through another conductor 47 passing through the interior of shaft 1 to the apparatus A being tested.
  • a V The collector illustrated in FIGURE 4 is advantageous in that it introduces a very low coefficient of friction in the operation of the centrifuge and has similarly a very moderate contact resistance while being practically free of eddy current.
  • FIGURE 5 the centrifuge rotor control means according to this invention.
  • the fairing or casing 14 surrounding the rotary members of the centrifuge carries a transverse annular disc 51 in which a number of spaced holes 52 are formed along its periphery.
  • these holes move past an optical detector comprising a light source 53 and a photo-electric cell 54 disposed above and under the disc 51, as shown.
  • the photocell 54 delivers electric pulses used for adjusting the velocity of rotation.
  • the photocell 54 is connected to the inlet of a frequency divider 55 having its output connected to the input of a phase discriminator 56.
  • a phase discriminator 56 On the other hand,
  • a reference pulse generator 57 monitored by a therrno'-.
  • phase discriminator 56 of any known and suitable type is used to compare the phases of the signals fed to its two inputs and delivers at its output end square signals of which the average value is proportional to the relative phase of the measure and reference signals.
  • the centrifuge correction is of the phase type or, in other words a position correction
  • this correction is stabilized by means of a phase-lead network 59 of which the output signal is fed to an amplifier modulator 60.
  • a potentiometer 61 also connected to the output of the phase-lead network 59 permits of modifying at will the average torque.
  • the output signal of modulator 60 is fed to a power amplifier 63 supplying the, torque motor 7 driving the centrifuge.
  • the signal necessary for operating the motor 7 by supplying the fixed phase is delivered by the quartz generator 57.
  • the square-waveform output signals issuing from the generator 57 are converted into sine waves by a selective amplifier 62 similar to amplifier 63 before feeding the fixed phase of motor 7.
  • phase corrector device described herein-above is suitable for providing a mean speed precision.
  • the capacitor of the control system consists, on the'one hand, of a metal disc 71 (FIGURE 1) rigid with the measuring plate 10 and projecting outside the fairing 1'4, and on the other hand of a pair of electrically insulated metal plates 72, 73 rigid with a support 74 carried by a stationary bracket 75.
  • a microfaradmeter 76 delivers a voltage proportional to the relative spacing between disc 71 and plates 72, 73. This voltage is read on the screen .of an oscillograph 77.
  • the device is calibrated through a known displacement of support 74, this displacement producing a variation in the voltage read on the screen of the oscillograph.
  • Means for checking the degree of balance of the centrifuge rotor are also provided. If the rotor is in a state of unbalance, vibrations occur in the frame structure 9. The amplitude of these vibrations is evidenced :by measuring same at a point where it attains a peak value. This measurement may be carried out by means of a C- meter or capacitance method similar to that set forth hereinabove in connection with the determination of variations in length of the arm 2.
  • plate on which the accelerometer or other apparatus A to be measured is secured, carries in addition a flat mirror 81.
  • a self-collimating sight 8 2 is mounted on a fixed support 83 sealed in the lateral wall 18 of the room.
  • the light source consists of the discharge of a capacitor in a spark-gap 84.
  • the mirror 81 In the inoperative condition the mirror 81 is brought in alignment with the sight 82 and the light beam reflected by this mirror 81 into the sight causes a luminous cross to appear in the eyepiece and the centering of the haircross is adjusted thereon.
  • a photograph is taken by means of a camera 85.
  • a flash from the light source 84 is produced when the mirror 81 moves past the sight 82.
  • the relative shift between the luminous cross and the reference hair-cross indicates the possible inclination of the measuring plate 10.
  • a precision centrifuge comprising a fixed frame structure, a vertical shaft carrying the objects subjected to the action 'of the centrifugal force, an electromotor rotatably driving said vertical shaft, a hydraulic, low-frictional torque footstep bearing carrying the lower end of said vertical shaft, an air bearing of practically zero frictional torque mounted on said frame structure and receiving the upper portion of said vertical shaft, an external casing of revolution rigid with said shaft and enclosing the rotary component elements of the centrifuge, an upper base plate rigid with said frame structure, supporting said air bearing and receiving said vertical shaft therethrough, a plurality of micrometric screws for adjusting the position of said air bearing on said base plate, and bracing wires, tensioning devices and springs attached together between said base plate and a plurality of fixed points surrounding the centrifuge, said tensioning devices permitting of adjusting the verticality of said vertical shaft by the elastic deformation of said frame structure.
  • Precision centrifuge as set forth in claim 1, comprising a radial arm rigid with said vertical shaft, a measuring plate secured on the end 'of said radial arm and carrying the object subjected to the action of the centrifugal force, and means for measuring the variation in length of said arm, said means comprising a metal element rigid with said measuring plate, a support adjustably mounted on said frame structure, a pair of metal plates carried by said support at the level of said metal element rigid with said measuring plate so that said element will move past said pair of metal plates during the operation of the centrifuge, and a faradmeter for measuring the variation in capacitance, during the rotation of the centrifuge, of the capacitor consisting on the one hand of said metal element carried by said measuring plate and on the other hand of said pair of metal plates carried by said support.
  • Precision centrifuge as set forth in claim 1, comprising a radial arm rigid with said shaft, a measuring plate mounted on the end of said radial arm and carrying the object to be subjected to the action of the centrifugal fonce, and means for controlling the inclination of said measuring plate, said means comprising a fiat mirror rigid with said measuring plate, a fixed support rigid with said frame structure, a self-collimating sight mounted on said fixed support and so positioned that said flat mirror moves past said sight during the rotation of said arm, a fixed flight source, means for switching on said light source as the mirror moves past said self-collimating sight, whereby said mirror will reflect the light beam issuing from said light source towards said sight to permit the checking of the variation in the inclination of said measuring plate.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Centrifugal Separators (AREA)
  • Magnetic Bearings And Hydrostatic Bearings (AREA)
  • Testing Of Balance (AREA)
US406833A 1963-11-21 1964-10-27 Precision centrifuge Expired - Lifetime US3313139A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR954564A FR1391760A (fr) 1963-11-21 1963-11-21 Centrifugeuse de précision

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US3313139A true US3313139A (en) 1967-04-11

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DE (1) DE1297035B (fr)
FR (1) FR1391760A (fr)
GB (1) GB1032309A (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4202205A (en) * 1978-05-26 1980-05-13 MRC Corporation Integral torquer for mass measurement system
WO2015139340A1 (fr) * 2014-03-18 2015-09-24 华中科技大学 Dispositif de support de suspension à gaz actif
CN106622682A (zh) * 2016-08-29 2017-05-10 贵州省玉屏县金心笛油脂开发有限公司 自动化榨油设备、榨油工艺
WO2020220428A1 (fr) * 2019-04-28 2020-11-05 浙江大学 Structure de cavité sous vide d'un dispositif centrifuge géotechnique à gravité ultra-élevée

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4014431C1 (fr) * 1990-05-05 1991-07-04 Heraeus Sepatech Gmbh, 3360 Osterode, De
GB2354372A (en) * 1999-09-17 2001-03-21 Damco Ltd Connector module and encoder arrangement for an electic motor

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB149372A (fr) *
US2683636A (en) * 1949-11-12 1954-07-13 Roy M Wilcox Air bearing
US2769949A (en) * 1954-03-23 1956-11-06 Gen Electric Method and apparatus for motor speed regulation
US2924092A (en) * 1955-05-06 1960-02-09 Bourns Inc Centrifugal calibration device
US3067620A (en) * 1958-01-09 1962-12-11 American Mach & Foundry Acceleration testing apparatus
US3205696A (en) * 1961-07-07 1965-09-14 Norman G Froomkin Precision rotary accelerator

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2465437A (en) * 1945-11-30 1949-03-29 George B Engelhardt High-g centrifuge
US2788654A (en) * 1953-04-06 1957-04-16 Wiancko Engineering Company Accelerometer testing system
NL114093C (fr) * 1957-12-27 1900-01-01
FR1298342A (fr) * 1960-03-17 1962-07-13 Reactor Centrum Nederland Centrifugeuse, notamment ultra-centrifugeuse, pour la séparation de gaz
IT649827A (fr) * 1960-03-23 1900-01-01

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB149372A (fr) *
US2683636A (en) * 1949-11-12 1954-07-13 Roy M Wilcox Air bearing
US2769949A (en) * 1954-03-23 1956-11-06 Gen Electric Method and apparatus for motor speed regulation
US2924092A (en) * 1955-05-06 1960-02-09 Bourns Inc Centrifugal calibration device
US3067620A (en) * 1958-01-09 1962-12-11 American Mach & Foundry Acceleration testing apparatus
US3205696A (en) * 1961-07-07 1965-09-14 Norman G Froomkin Precision rotary accelerator

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4202205A (en) * 1978-05-26 1980-05-13 MRC Corporation Integral torquer for mass measurement system
WO2015139340A1 (fr) * 2014-03-18 2015-09-24 华中科技大学 Dispositif de support de suspension à gaz actif
US9920790B2 (en) 2014-03-18 2018-03-20 Huazhong University Of Science And Technology Active airbearing device
CN106622682A (zh) * 2016-08-29 2017-05-10 贵州省玉屏县金心笛油脂开发有限公司 自动化榨油设备、榨油工艺
WO2020220428A1 (fr) * 2019-04-28 2020-11-05 浙江大学 Structure de cavité sous vide d'un dispositif centrifuge géotechnique à gravité ultra-élevée

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Publication number Publication date
GB1032309A (en) 1966-06-08
FR1391760A (fr) 1965-03-12
DE1297035B (de) 1969-06-04

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