US3664151A - Spindle for centrifuges - Google Patents

Spindle for centrifuges Download PDF

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Publication number
US3664151A
US3664151A US866882A US3664151DA US3664151A US 3664151 A US3664151 A US 3664151A US 866882 A US866882 A US 866882A US 3664151D A US3664151D A US 3664151DA US 3664151 A US3664151 A US 3664151A
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United States
Prior art keywords
spindle
region
basket
bending
frame
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Expired - Lifetime
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US866882A
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English (en)
Inventor
Kurt Pause
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BWS Technologie GmbH
Original Assignee
Maschinenfabrik Buckau R Wolf AG
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    • 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
    • B04B9/12—Suspending rotary bowls ; Bearings; Packings for bearings
    • 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
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F15/00—Suppression of vibrations in systems; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion
    • F16F15/10—Suppression of vibrations in rotating systems by making use of members moving with the system

Definitions

  • At'torneyMichael S. Striker [30] Foreign Application Priority Data [57] ABSTRACT Oct. 16, 1968 Gennany ..P 18 032 49.0 A Spindle which forms part of a Suspended centrifugal and is mounted in the machine frame at its upper end. The bowl or basketisanached tothelowerend ofthe spindle and thelauer tapers from the lower toward the upper end so that its flexural [58] Freld of Search ..64/1, 210/366, 267/57 Strength is at least substantially constant a the way from the PEDTL BERANL'E OF Q ⁇ F A hub of the bowl or basket to the bearing in the frame.
  • the present invention relates to centrifuges in general, and more particularly to improvements in spindles for centrifuges of the type wherein the spindle is designed to support the basket or bowl in such a way that the basket or bowl is suspended on the spindle and can perform swinging or pendulum movements. Suspended centrifugals are typical of such classes of centrifuges.
  • Swingably mounted baskets or bowls are preferred in centrifuges wherein the load is likely to produce unbalance. This is the case in centrifuges which are used in sugar refineries and which are operated periodically, i.e., whose rotational speed varies so that the components must stand repeated acceleration and deceleration, for example, between a minimum and a maximum rotational speed or even between zero speed and a maximum speed or vice versa.
  • the rotary parts of a centrifuge with a swingable bowl or basket constitute a so-called symmetrical heavy gyroscope or top.
  • the center of gravity of the gyrating system is located below the point of suspension.
  • the system constantly tends to maintain the moment of inertia of its mass in a position which is symmetrical with reference to the axis of rotation.
  • the gyrating system compensates for each interference due to an unbalance by producing an oppositely directed gyroscopic couple of equal magnitude.
  • the basket tends to move in parallelism with the axis of the revolving structure.
  • the newly formed axis of rotation is then parallel to the original axis. If the unbalance develops outside of the center of gravity plane, the basket tends to establish a new axis of rotation which is inclined with reference to the original axis.
  • the spindle of the centrifuge opposes such shifting of the axis of rotation because one of its ends is joumalled in the frame of the machine. Consequently, the basket must flex the spindle in order to establish a new axis of rotation.
  • the flexing is terminated when the bending moment (which equals the gyroscopic couple) is balanced by the moment produced by the bending stress upon the spindle.
  • the force which counteracts the bending moment due to correction for unbalance is transmitted to and is taken up by the frame or foundation of the machine.
  • Such counteracting force is transmitted through the bearing means for the spindle, i.e., through the center of the gyrating system, and it travels in the frame at the rotational speed of the basket to excite" the frame to the extent determined by the characteristic deformability or plasticity of the frame.
  • excitation of the frame can produce resonance, especially since the rotational speed of the gyrating system normally covers the full range from zero speed to maximum speed.
  • the center of the gyrating system begins to move in space which, in turn, initiates swiveling movements of the system.
  • the axis of the gyrating system travels along a conical path at a frequency which is a function of the mass and of the distance between the center of gravity and the center of the gyratory system.
  • the swiveling movements of the gyrating system are either damped or amplified.
  • Such swiveling movements are invariably assisted by friction which develops at the swingable bearing cup; at the very least, such friction delays the damping of vibratory movements and the return of the frame to quiescent condition.
  • spindles for use in suspended centrifugals or like machines. Such spindles were designed to exhibit sufficient flexibility in view of anticipated stresses due to unbalances and also to offer to bending stresses a resistance which is less than that at which the forces travelling in the support for the spindle would attain an undesirable magnitude.
  • presently known spindles are of cylindrical shape and their diameter is constant all the way from the point of suspension in the frame to the point of fixedly mounting the spindle in the hub of the basket. The bending moment is zero at the point of suspension and is greatest at the point where the spindle is mounted in the hub.
  • centrifuges are thus faced with two conflicting problems.
  • the moment of resistance of the spindle is to be increased to avoid excessive bending and eventual destruction or danger of accidents with oversized centrifuges.
  • a stronger spindle offers a greater resistance to bending with the result that the frame is subjected to excessive stresses; this again increases the likelihood of damage, accident or destruction.
  • An object of the present invention is to provide a novel and improved spindle for use in suspended centrifugals and analogous centrifuges and to design the spindle in such a way that it can take up and/or resist substantial bending stresses without, however, permitting excessive stressing of its bearings or other stationary parts of the machine.
  • Another object of the invention is to provide a spindle which is designed and constructed by full consideration of static and dynamic factors which arise when the spindle is used to support a load-accommodating container in a centrifugal machine.
  • the improved spindle is preferably of the type which is mounted in upright position and is joumalled in the frame at its upper end.
  • the lower end of the spindle is connected with and supports the hub of a bowl or basket.
  • the spindle tapers from its lower end toward its upper end in such a way that its flexural strength (resistance to bending) is at least substantially uniform all the way between the two ends.
  • FIGURE is a fragmentary axial sectional view of a centrifuge including a spindle which embodies the invention.
  • the spindle of the present invention is configurated, constructed and machined in such a way that it constitutes a body having a uniform resistance to bending all the way from the point of attachment of the hub of a bowl, basket or a like loadaccommodating container to the point where the spindle is mounted in the bearing structure of the machine frame. Otherwise stated, the bending resistance or flexural stiffness of the entire exposed part of the spindle is at least nearly constant. This is achieved by imparting to the spindle a conical shape, i.e., the spindle tapers from the hub of the basket toward the point of suspension of the spindle.
  • the just described novel spindle was designed on the basis of the following considerations:
  • the flexing of a spindle for the container of a centrifugal machine, especially a suspended centrifugal, is analogous to the stressing of a cantilever beam one end of which is mounted in a support and the other or free end of which takes the load. If the dimensioning, and hence the moment of resistance of the beam is uniform along its full length, the maximum flexing stresses. develop at the point of the maximum bending moment, i.e., at the point where the beam is fixedly mounted in the hub.
  • the value of the tangent of the bending angle is greatest at the point of mounting of the beam, and such value decreases in a direction toward and is zero at the point where the load acts on the free end of the beam.
  • the maximum permissible tangent of the bending angle is a function of the material of the beam. If the deformation of the beam is to remain within the elastic limits of its material (i.e., if a permanent deformation is to be avoided), the maximum value of the tangent cannot be exceeded.
  • the characteristic curve of bending of the beam is a parabola of higher order. The maximum deformation (i.e., the extent of movement of the free end of the beam from its position in unstressed condition of the beam) can be determined in advance.
  • the beam can be designed in such a way that its moment of resistance remains the same at each point of its length, i.e., the moment of resistance can be constant and just large enough to insure that the flexural strength of the beam is uniform from end to end.
  • the value of the tangent of the bending angle at each point of the beam is the same.
  • the characteristic bending curve of the thus designed beam is a portion ofa circle. If the moment of resistance of the beam at the point of its mounting is the same as in the previously considered case (beam of constant diameter from end to end), the total deformation of the modified beam at the same length and assuming that the load thereon is the same will exceed the total deformation of the previously discussed beam.
  • a spindle which is constructed in accordance with my invention exhibits the additional advantage that the moment of resistance at the point where the spindle is mounted in the hub can be greater than in known spindles to thus further reduce the likelihood of permanent deformation at the point which is subjected to maximum stresses despite the fact that the spindle, as a whole, is more readily deformable and insures better control of forces which act on the frame of the centrifugal machine.
  • the drawing shows a portion of a centrifuge having a housing or frame 5 for a swivel bearing 6 which surrounds a sleeve 7 at the upper end 4 ofa tapering spindle 3.
  • the lower end 4a of the spindle 3 is fixedly connected with the hub 2 of a container or basket 8.
  • the character 9 denotes a mass of sugar in the interior of the container 8.
  • the mass 9 has an inwardly extending protuberance 10 which causes unbalance of the revolving parts.
  • the numeral 11 denotes the point where the spindle 10 is subjected to the action of a bending force P
  • the force which causes unbalance is shown at P
  • the bending moment M is b.P B
  • the moment of unbalance M is a.P
  • An equilibrium is established when M equals M
  • a spindle for use in centrifugal machines of the type wherein the spindle is swingably and rotatably mounted in the region ofits upper end and fixedly mounted in the region of its lower end in the hub of a load accommodating container carried by the spindle, said spindle tapering continuously from the region of said lower to said region of its upper end.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Centrifugal Separators (AREA)
  • Rolls And Other Rotary Bodies (AREA)
  • Rigid Containers With Two Or More Constituent Elements (AREA)
US866882A 1968-10-16 1969-10-16 Spindle for centrifuges Expired - Lifetime US3664151A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19681803249 DE1803249C2 (de) 1968-10-16 1968-10-16 Zentrifugenwelle

Publications (1)

Publication Number Publication Date
US3664151A true US3664151A (en) 1972-05-23

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ID=5710584

Family Applications (1)

Application Number Title Priority Date Filing Date
US866882A Expired - Lifetime US3664151A (en) 1968-10-16 1969-10-16 Spindle for centrifuges

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US (1) US3664151A (enrdf_load_stackoverflow)
CS (1) CS150283B2 (enrdf_load_stackoverflow)
DE (1) DE1803249C2 (enrdf_load_stackoverflow)
FR (1) FR2020808A1 (enrdf_load_stackoverflow)
GB (1) GB1258981A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4511350A (en) * 1983-10-06 1985-04-16 E. I. Du Pont De Nemours And Company Suspension system for a centrifuge rotor
US5069413A (en) * 1988-04-11 1991-12-03 E. I. Du Pont De Nemours And Company Centrifuge motor mount having two slotted members
US6428460B1 (en) * 1998-02-19 2002-08-06 Alfa Laval Ab Support device for a centrifugal separator providing axial and radial support
US20140256528A1 (en) * 2011-11-24 2014-09-11 Bma Braunschweigische Maschinenbauanstalt Ag Discontinuous centrifuge with a scraper for scraping a product
CN112743392A (zh) * 2019-10-30 2021-05-04 大隈株式会社 机床中的主轴转速的监视装置及监视方法、机床

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US96186A (en) * 1869-10-26 Henry w
US2213004A (en) * 1939-01-12 1940-08-27 Hickman Pneumatic Seat Co Inc Torsion rod mounting

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH909A (fr) * 1889-04-29 1889-08-09 David Junior Hummel Nouvelle turbine centrifuge pour la séparation des liquides
FR372556A (fr) * 1906-02-05 1907-04-11 Nils Svensson Boek Essoreuse
US897916A (en) * 1907-01-21 1908-09-08 Hubert A Myers High-speed rotary device.
BE332953A (enrdf_load_stackoverflow) * 1925-04-06

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US96186A (en) * 1869-10-26 Henry w
US2213004A (en) * 1939-01-12 1940-08-27 Hickman Pneumatic Seat Co Inc Torsion rod mounting

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4511350A (en) * 1983-10-06 1985-04-16 E. I. Du Pont De Nemours And Company Suspension system for a centrifuge rotor
US5069413A (en) * 1988-04-11 1991-12-03 E. I. Du Pont De Nemours And Company Centrifuge motor mount having two slotted members
US6428460B1 (en) * 1998-02-19 2002-08-06 Alfa Laval Ab Support device for a centrifugal separator providing axial and radial support
US20140256528A1 (en) * 2011-11-24 2014-09-11 Bma Braunschweigische Maschinenbauanstalt Ag Discontinuous centrifuge with a scraper for scraping a product
US9764337B2 (en) * 2011-11-24 2017-09-19 Bma Braunschweigische Maschinenbauanstalt Ag Discontinuous centrifuge with a scraper for scraping a product
CN112743392A (zh) * 2019-10-30 2021-05-04 大隈株式会社 机床中的主轴转速的监视装置及监视方法、机床
CN112743392B (zh) * 2019-10-30 2024-06-07 大隈株式会社 机床中的主轴转速的监视装置及监视方法、机床

Also Published As

Publication number Publication date
GB1258981A (enrdf_load_stackoverflow) 1972-01-05
CS150283B2 (enrdf_load_stackoverflow) 1973-09-04
DE1803249C2 (de) 1970-10-22
FR2020808A1 (enrdf_load_stackoverflow) 1970-07-17
DE1803249B1 (de) 1970-03-05

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