US3402822A - Screening centrifuges - Google Patents

Screening centrifuges Download PDF

Info

Publication number
US3402822A
US3402822A US572981A US57298166A US3402822A US 3402822 A US3402822 A US 3402822A US 572981 A US572981 A US 572981A US 57298166 A US57298166 A US 57298166A US 3402822 A US3402822 A US 3402822A
Authority
US
United States
Prior art keywords
screen
helix
bearing
screening
centrifuge
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US572981A
Other languages
English (en)
Inventor
Haakon C F Oyen
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.)
Dorr Oliver Inc
Original Assignee
Dorr Oliver Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dorr Oliver Inc filed Critical Dorr Oliver Inc
Priority to US572981A priority Critical patent/US3402822A/en
Priority to GB37009/67A priority patent/GB1186110A/en
Priority to DE19671632283 priority patent/DE1632283A1/de
Priority to SE11522/67A priority patent/SE330510B/xx
Application granted granted Critical
Publication of US3402822A publication Critical patent/US3402822A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B3/00—Centrifuges with rotary bowls in which solid particles or bodies become separated by centrifugal force and simultaneous sifting or filtering
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B3/00—Centrifuges with rotary bowls in which solid particles or bodies become separated by centrifugal force and simultaneous sifting or filtering
    • B04B3/04—Centrifuges with rotary bowls in which solid particles or bodies become separated by centrifugal force and simultaneous sifting or filtering discharging solid particles from the bowl by a conveying screw coaxial with the bowl axis and rotating relatively to the bowl

Definitions

  • the present invention relates to screening Centrifuges of the type having a conical screen and a helical conveyor therein to move solids along the screen. In such Centrifuges, it is common to introduce the feed material at the narrow end of the screen. Centrifugal force urges the feed material radially outwardly against the screen where there occurs a separation of one fraction of the feed material, for example a liquid, which passes through the screen, from a second fraction, for example solids, which is retained on the screen.
  • the conveyor of the centrifuge has helical vanes and is positioned within the screen with a predetermined clearance therebetween. As is conventional, the conveyor is rotated with the screen but at a speed ydifferential whereby the helical vanes effect an apparent traverse from the narrow to the wide end of the screen and thus control the axial transfer of the solids along the screen.
  • the present invention results from a problem occurring in the use of such prior art screening Centrifuges.
  • the problem phenomenon occurred when the centrifuge feed rate was increased above the point which was presumed by the art to be maximum machine capacity.
  • Such increased feed rates were met with marked vibration and with a rapidly increasing torque between the differentially rotating screen and helix.
  • a scribing point was mounted on a screen-associated component of the prior art centrifuge with a .005" vertical clearance from a horizontal surface on the helix. The centrifuge was run up to the vibration and overload Value of feed rate. Subsequent examination showed a score in the helix and a broken scribe point, thus indicating the helix had lifted at least .005".
  • the present invention provides a solution to these problems by restraining t-he helix axially with respect to the screen.
  • this restraint is provided by a zero-end-play bearing arrangement as fully described below. Centrifuges with this unique bearing arrangement have been tested and found to be free of the vibrational problem. Further, the improved Centrifuges can handle, at the maximum permissible torque for the differential drive, a feed rate approximately 240% greater than the same Centrifuges having the prior art bearing arrangement.
  • FIGURE 1 is a vertical section of the screening centrifuge of the present invention incorporating a zero-endplay bearing between the dri-ve shafts for the centrifuge screen and helix to prevent axial movement therebetween.
  • FIGURE 2 is a detail section showin-g the clearance between the opposite faces of the helix vanes and the screen of FIGURE 1 and shows the layer of solids which occupies this clearance during operation.
  • FIGURE 3 is an enlarged, fragmentary, vertical section showing in exaggerated manner the raceway offsets of the Considering the detail structure of the illustrated rotorl of FIGURE 1, the screening centrifuge of the present invention includes a rotor 11 having an inlet opening 12 for feeding process material to the rotor as indicated by arrows 14.
  • the feed material passes to an annular conical space 16 in the rotor between a foraminous conical screen 19 (FIGURE 2), which is carried on the interior surface of a rapidly rotating perforated cage or screen support 18, and a rotating conveyor or helix 20.
  • the rotation of cage 18 and screen 19 urges the process material against the screen.
  • the screen retains one portion of the feed material, for example solids, while another portion of the feed material, for example a liquid, is centrifugally forced through the screen as indicated by arrows 22.
  • the liquid is collected in one or more chambers of the centrifuge housing (not shown) in conventional manner.
  • the material 23 (FIGURE 2) retained on screen 19 ⁇ moves downwardly under control of vanes 40 on the helix.
  • the pictorial representation of helical vanes 40 has been simplified in FIGURE 1 to show the screen-to-helix clearance throughout the axial length of the rotor whereas in FIG- URE 2 the true sectional appearance of a helical vane is shown.
  • the helix rotates in the same direction as screen 19 but at a speed differential whereby an axial conveying action is effected.
  • the solids are finally discharged from rotor 11 through openings 42 as indicated by arrows 44 and are collected in a solids chamber of the centrifuge housing (not shown) in conventional manner.
  • a drive head assembly 58 is provided to rotatably support and drive the screen and the helix of the rotor.
  • Drive head assembly 58 includes a fixed, double-coneshaped, support housing 60 havin-g bearing assemblies 62 and 64.
  • An annular outer shaft assembly 66, which drives cage 18, is mounted to rotate within these bearing assemblies.
  • a coaxial inner shaft assembly 68, which drives helix 20, is mounted by bearing ⁇ assemblies 70 and 72 to rotate within outer shaft assembly 66.
  • shaft assemblies 66 and 68 are driven at differential speeds by a suitable drive arrangement such as transmission 80 which is completely described in U.S. Patent 3,332,300, issued July .25, 1967.
  • the transmission is powered by a belt pulley 82 which is in turn driven by a belt or belts 84 which extend from a power source such as a motor (not shown).
  • rotor 11 includes annular rings 90 and '92 suitably secured to the upper open end of cage 18 to form feed inlet opening 12.
  • Cage 18 is formed by a conical member 94 which has a plurality of perforations or slots 96 therein for passage of effluent to the fluid chambers of the centrifuge housing (not shown) which surrounds the rotor.
  • the cage is secured by screws 98 to a spider ring 100 containing the solids apertures 42.
  • the ring is in turn secured by screws 102 to a bell-like hub 104, and the hub is non-rotatably connected to a hollow shaft 106 of outer shaft assembly 66 by any suitable means such as cap screws (not shown).
  • Helix 20 includes a lower conical portion 110 secured by a key 114 to rotate with a shaft 112 of inner shaft assembly 68.
  • An upper conical portion 116 of the helix is connected to lower portion 110 by cap screws 118.
  • helix 20 of the screening centrifuge is provided with two series of passages 122, 124 and 126, 128, 130, 132 to supply a wash fluid or fluids from concentric wash fluid feed pipes 134 and 136 to the material being processed in the rotor.
  • Outer shaft assembly 66 further includes a bearing spacer 140 between the inner races of outer shaft bearing assemblies 62 and 64; a lock nut assembly 148 to clamp the inner races of bearing assembly 62, bearing spacer 140, and the inner races of bearing assembly 64 all in place against a shoulder 149 of outer rotor shaft 106;
  • Inner shaft assembly 68 is provided with a sealing arrangement 142 between cage hub 104 and inner shaft 112 and a lock nut assembly 144 to clamp the inner races of bearing assembly 70 upon a shoulder 145 of inner shaft 112.
  • Support housing 60 includes a seal assembly 150 to provide a seal between the stationary housing and the rotating hub 104. Housing 60 is further provided with a retainer 152 to maintain the 'outer races of bearing assembly 64 in position against shoulder 153 of the housing.
  • bearing arrangements Considering the bearing arrangements and their functions in greater detail, it is customary in conveyor-type screening :centrifuges to support each of the rotary components in two spaced-apart anti-friction bearing assemblies.
  • One of these bearing assemblies serves to position the component axially, within the limits of the bearing play, and the other bearing assembly is arranged to permit axial floating to compensate for manufacturing tolerances and for differential thermal expansion of the housing and/or shafts.
  • outer shaft 106 is axially positioned with respect to the housing by lower bearing assembly 64, the inner and outer races of lwhich are rigidly mounted on the shaft and housing, respectively.
  • the outer shaft upper bearing assembly 62 is mounted with its outer races floating in the housing for the above-mentioned purposes.
  • inner shaft 112 is positioned axially with respect to outer shaft 106 by upper bearing assembly 70, the inner and outer races of which are rigidly mounted on inner shaft 112 and in outer shaft 106, respectively. But, the lower end of inner shaft 112 is free to float axially with respect to the outer shaft in roller bearing assembly 72.
  • outer shaft bearings which are heavier duty than the inner shaft bearings and which in many cases are double-row, zero-radial-play bearings to alleviate vibrational problems at these relatively high rotational speeds.
  • the prior lart inner shaft bear-ings commonly have been single row bearing arrangements.
  • single-row rolling-element bearings inherently have a degree of end play. This end play can be eliminated only if special provisions or procedures are utilized in a double-row bearing arrangement. Therefore, in order to prevent axial helix movement within the screen, a zero-end-play, double-row bearing is provided in the present invention as the upper bearing between the shafts. By positioning the zero-end-play bearing between the upper or helix/ screen proximate ends of the shafts, helix shift due to differential thermal expansion of the shafts is avoided. f-
  • a double-row, zero-endplay bearing assembly 70 in which the rolling elements are balls, is utilized between the shafts.
  • a shim or shims are inserted during installation between the respective inner races '182 and 184.
  • Outer races 186 and 188 are forced together during assembly by clamping ring 146 so as to preload the bearing.
  • This forcible clamping creates an offset between the centerlines and 192 of the raceways of races 182 and 186.
  • a similarv but oppositely directed offset is created between centerlines 194 and 196 of the raceways of races 184 and 188, respectively.
  • the effect of these raceway offsets is depicted in exaggerated manner in FIGURE 3 by the contact relationships between the balls and the raceways and by the illustrated force arrows indicating the direction of preload forces between the races and the balls.
  • shims were selected to create an axial preload in the range of 90 to 130 pounds. It should be noted that alternatively a similar although inverse preload relationship could be effected by a shim between the outer races with the inner races being clamped together.
  • Other zero-end-play bearing techniques are visualized for incorporation in the present invention. For example, instead of installing shims between either the inner or the outer bearing races, a portion of one or both of the inner or outer races can be removed as by grinding to achieve analogous raceway offsets and preloads. Other conventional zero-end-play bearing arrangements can also be used in the present invention.
  • bearing system is a double-row ball bearing arrangement with a preload in the range of 90 to 130 pounds axially.
  • each said row of balls has separate inner and outer races and wherein a shim means is installed between the respective races on one of said shafts with the respective races on the other shaft being clamped together to establish said opposite axial raceway offsets.

Landscapes

  • Centrifugal Separators (AREA)
US572981A 1966-08-17 1966-08-17 Screening centrifuges Expired - Lifetime US3402822A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US572981A US3402822A (en) 1966-08-17 1966-08-17 Screening centrifuges
GB37009/67A GB1186110A (en) 1966-08-17 1967-08-11 Screening Centrifuges.
DE19671632283 DE1632283A1 (de) 1966-08-17 1967-08-11 Siebzentrifuge
SE11522/67A SE330510B (enExample) 1966-08-17 1967-08-16

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US572981A US3402822A (en) 1966-08-17 1966-08-17 Screening centrifuges

Publications (1)

Publication Number Publication Date
US3402822A true US3402822A (en) 1968-09-24

Family

ID=24290151

Family Applications (1)

Application Number Title Priority Date Filing Date
US572981A Expired - Lifetime US3402822A (en) 1966-08-17 1966-08-17 Screening centrifuges

Country Status (4)

Country Link
US (1) US3402822A (enExample)
DE (1) DE1632283A1 (enExample)
GB (1) GB1186110A (enExample)
SE (1) SE330510B (enExample)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4412707A (en) * 1981-12-30 1983-11-01 Robatel Slpi Bearing device for centrifuge
CN115228625A (zh) * 2022-07-18 2022-10-25 江苏同泽过滤科技有限公司 一种沉降过滤离心机中沉降和过滤机构的安装结构

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2043661A (en) * 1934-08-10 1936-06-09 Andrew F Howe Centrifugal driving mechanism
US2370353A (en) * 1940-09-19 1945-02-27 Andrew F Howe Centrifugal separator or clarifier
US3071228A (en) * 1956-09-10 1963-01-01 Borg Warner Clutch device
US3332300A (en) * 1964-06-10 1967-07-25 Dorr Oliver Inc Centrifugal equipment

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2043661A (en) * 1934-08-10 1936-06-09 Andrew F Howe Centrifugal driving mechanism
US2370353A (en) * 1940-09-19 1945-02-27 Andrew F Howe Centrifugal separator or clarifier
US3071228A (en) * 1956-09-10 1963-01-01 Borg Warner Clutch device
US3332300A (en) * 1964-06-10 1967-07-25 Dorr Oliver Inc Centrifugal equipment

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4412707A (en) * 1981-12-30 1983-11-01 Robatel Slpi Bearing device for centrifuge
CN115228625A (zh) * 2022-07-18 2022-10-25 江苏同泽过滤科技有限公司 一种沉降过滤离心机中沉降和过滤机构的安装结构
CN115228625B (zh) * 2022-07-18 2023-11-14 江苏同泽过滤科技有限公司 一种沉降过滤离心机中沉降和过滤机构的安装结构

Also Published As

Publication number Publication date
GB1186110A (en) 1970-04-02
SE330510B (enExample) 1970-11-16
DE1632283A1 (de) 1970-07-09

Similar Documents

Publication Publication Date Title
US4345799A (en) Bearing assembly
US3038575A (en) Fluid pressure operated clutch with stationary cylinder assembly
JPH053352B2 (enExample)
US2009964A (en) Uni-directional end-thrust bearing
US3428247A (en) Centrifuge lubricating and seal system
GB1476348A (en) Cooling water pumps for vehicle engines
US5667314A (en) Horizontal thrust bearing assembly
US3402822A (en) Screening centrifuges
US3122399A (en) Self-balancing bearing construction
US4093323A (en) Rotor bearing
US20050058381A1 (en) Roller bearing
US4322117A (en) Thrust bearing
SE455633B (sv) Lagerhus med oljetransportsmorjning for horisontell lagring av en axel
US3031239A (en) Roller or needle thrust bearings
SE437412B (sv) Anordning for tetning av ett sjelvinstellande rullningslager
JP2001012481A (ja) 軸受装置
US4629197A (en) Cone crusher labyrinth seal
US6589154B2 (en) Decanter centrifuge with a gear box mounted on the bowl
US2704157A (en) Speed control system for centrifugals and other machines
US3332300A (en) Centrifugal equipment
US2234574A (en) Bearing of gyratory centrifugal devices
US4588310A (en) Bearing arrangement to be submerged in water or a slurry
US3424312A (en) Wash arrangement for screen centrifuges
JP5147726B2 (ja) 遠心分離機用ギアボックス
US3713711A (en) Rolling contact bearing accelerator