US3595470A - Control apparatus for centrifuge - Google Patents

Control apparatus for centrifuge Download PDF

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Publication number
US3595470A
US3595470A US771156A US3595470DA US3595470A US 3595470 A US3595470 A US 3595470A US 771156 A US771156 A US 771156A US 3595470D A US3595470D A US 3595470DA US 3595470 A US3595470 A US 3595470A
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Prior art keywords
bowl
control liquid
centrifuge
pocket
centrifuge according
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Expired - Lifetime
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US771156A
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English (en)
Inventor
Leonard Shapiro
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Pennwalt Corp
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Pennwalt Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B11/00—Feeding, charging, or discharging bowls
    • B04B11/04—Periodical feeding or discharging; Control arrangements therefor
    • B04B11/043—Load indication with or without control arrangements
    • 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

Definitions

  • This invention relates to control apparatus for centrifuges operated on a cyclical-sludge-discharge basis, and more particularly to automatic means for detecting or sensing the extent of sludge buildup and for initiating removal of the accumulated sludge from the bowl by suitable discharging means.
  • a timer has previously actuated the sludge removal equipment, usually a skimmer which initially leads the clarified liquid to discharge. Subsequently, as the skimmer reaches the sludge cake an operator, seeing the sludge in the skimmer discharge, diverts it to waste. When sludge has been removed from the bowl to the extent practicable, the skimmer is returned to its inward rest position and feed to the bowl is resumed.
  • the present invention there is provided an extremely simple and virtually foolproof means for detecting the sludge level in a solid bowl centrifuge and for actuating the sludge discharge mechanism.
  • the present arrangement provides for the actuation of the sludge discharge cycle when and as necessary but before sludge is actually present in the effluent, thereby avoiding any escape of solids into the clarified liquid. This is in contrast to the optical opacity and density means which indeed did not even commence to function until the effluent become clouded with sludge.
  • FIG. 1 is a sectional view of a centrifuge embodying the invention and showing in schematic form some of the controls thereof;
  • FlG. 2 is an enlarged fragmentary sectional view of the cen' trifuge of FIG. 1, taken along line 2-2 thereof;
  • FIG. 3 is an enlarged fragmentary sectional view, taken along line 3-3 of H6. 2;
  • FIG. 4 is a fragmentary view of FIG. I showing a modified peripheral wall of the centrifuge bowl, with perforations.
  • the invention involves pressure-responsive, automatic sludge discharge arrangement for a cyclically unloading centrifuge.
  • the dumping cycle is actuated upon the buildup of sludge in the bowl to a certain level, as indicated by a buildup of back pressure in a line supplying control liquid, and thereafter the feed is discontinued, the dumping of the sludge is automatically efficiently accomplished, and the feed is resumed.
  • FIG. 1 an arrangement embodying the invention is indicated in FIG. 1 and the apparatus is generally designated if).
  • lt comprises a base 12 having a plurality of upstanding standards 14, only one of which is shown.
  • Suspension means 16 attached to the standards 14 hang the centrifuge bowl housing 18.
  • the centrifuge bowl 22 is mounted on a shaft which passes through the bearing and mounts on its lowerend a pulley 24.
  • the pulley is driven by belt means 25 from the motor 26.
  • the bowl 22 presents an imperforate bottom wall 28 and peripheral wall 30.
  • the upper end wall 31 is likewise imperforate and provides a discharge lip 32.
  • More or less axial and radial vanes may be provided in the bowl 22 at its periphery.
  • Feed slurry is introduced to the bowl 22 through a feed tube 34 stationarily mounted over the bowl.
  • the feed slurry comprises a forward mixture of at least two materials wherein one material has a higher specific gravity than the other material and thus tends to build up on the periphery of the bowl 22.
  • the tube 34 is provided with a valve 36 operated by a solenoid 38.
  • a feed-receiving cup 40 is mounted on the top of the bowl hub and rotates with the bowl 22. From the cup 40 a plurality of feed conduits 42 extend longitudinally of the bowl down to the bowl bottom. The ends of the conduits 42 have openings and pass the feed slurry into the bowl 22 with little turbulence.
  • the effluent outlet conduit 44 Connected to the lower end of the centrifuge bowl housing 18 is the effluent outlet conduit 44. This leads the conduit to an effluent tank 46 from which the product effluent is drawn.
  • the centrifuge For removing the sludge in the cyclical operation the centrifuge is provided with a skimming device 50.
  • a skimming device 50 This includes a tube 51 of substantially J-shaped which presents an open mouth 52 facing the direction of rotation of the bowl 22.
  • the skimmer is mounted on the housing 18 in a plurality of bosses 54 in which the skimmer device is longitudinally movable. As in the past the basic operation of the skimmer 50 is similar to other skimmers.
  • Means for driving the skimmer device are indicated schematically at 56. These means may comprise a pair of pneumatic piston-cylinder assemblies which drive the skimmer alternately forward and back respectively.
  • the drive means 56 is carefully arranged so that at one inward extreme of travel the skimmer is disposed with its mouth 52 out of the liquid in the bowl 22 and inward of the lip 32. At the other or outward end of its travel the skimmer mouth 52 has an extreme of roughly one-fourth inch from the peripheral wall 57 of the bowl 22 so that it can remove nearly all of the sludge settled against the peripheral wall 57 of the bowl.
  • Limit switches, valves, or other devices assure the ends of travel and may be incorportated with the bosses 54 to effect reversal of the drive means 56.
  • the control liquid ring 60 is, of course, annular and is channel shaped in cross section as shown in the drawing.
  • the ring 60 may be welded or otherwise attached with the ribs 58 to the top wall 31 of bowl 22 in coaxial relationship therewith; and is very preferably arranged so that the floor of the channel section is at the same radial level as the effluent discharge lip 32 of the centrifuge if the peripheral bowl wall 57 is imperforate.
  • the ring 60 is formed about its circumference with equispaced threaded openings in its floor or web and into each opening is threadedly received a sludge level sensing tube 62.
  • each tube 63 is inclined to the rotational axis to extend outwardly and axially downward, terminating outwardly of the lip 32 of the maximum desired sludge level A of the bowl 22.
  • the outer end of the tube 62 has a restricted outlet 63 to assure proper obstruction of the opening in plate 66 by sludge as the sludge builds up inward. The position of the outer end of the tube 62 will determine the level to which sludge buildup is permitted before the sludge-unloading cycle commences.
  • the effluent tank 46 has connected to it a liquid line 64 which may lead to a pump (not Shown). If desired, the line 64 may further extend, as by broken line 65, to the top of the centrifuge housing 18 to provide the control liquid. As shown, however, it is optional that a separate feed line 66 from a source of pressurized liquid, e.g., water, provides the control liquid. Line 66 carries the control liquid through a flow control valve 67, a pressure-responsive switch 68, and thence through a discharge nozzle 69 positioned as shown well into the pocket of ring 60 with clearance therebetween.
  • a source of pressurized liquid e.g., water
  • control liquid feed line 66 which discharges control liquid at a very low rate, for instance, onehalf gallon per minute, may run continuously or may be shut off with the feed through pipe 34.
  • the control liquid preferably has a lower specific gravity than that of the accumulated solids, and preferably is the same material as the effluent.
  • the pressure-responsive solenoid switch 68 is set to be open at normal line pressure of the control liquid fed through line 66, adjustably maintained at a predetermined setting by flow control valve 67 so long as the drain tubes 64 remain unobstructed to permit emptying of the ring 60. However, when sludge builds up to the level A the outlet 63 of tubes 64 are obstructed and the level of control liquid in ring 60 builds up in wardly to immerse the nozzles 69 and thereby resist discharge of control liquid from the nozzles 69. Such resistance immediately creates a back pressure in the feed line 66, which back pressure is detected by the pressure-responsive switch 68. A predetermined increase in pressure detected by switch 68 actuates the closing thereof and initiates the closing of the feed tube 34 and the driving means 56 for the skimmer 50.
  • the pressure-responsive switch 68 is electrically connected to the feed valve solenoid 38 and to the skimmer drive means 56. It is also optionally connected to the control liquid line solenoid valve, which may be incorporated in flow control valve 67 and connected in the electrical circuitry by a line shown clotted and identified by number 79.
  • a trip which may take the form of any kind of a lug or protuberance 80 rigidly or adjustably mounted on the skimming device.
  • a limit switch 82 which is actuated by the lug 80 in either direction of travel of the skimming device.
  • the limit switch 82 is connected as shown to a solenoid-operated diversional valve 84 which normally (when not tripped) directs material flowing through skimmer pipe 51 to an effluent collection container, e.g., tank 46.
  • divisional valve 84 is arranged so that when the limit switch 82 is tripped in one direction, as when the skimmer tube 51 is driven outward toward the bowl wall 57, the solenoid-operated diversional valve 84 is thrown to the waste" position. On inward return of the skimmer tube 51 when the lug 80 disengages the limit switch 82 the solenoid-operated diversional valve 84 is operated in the reverse direction to normal position wherein the flow from the skimmer tube 51 is again directed to the effluent collection container, e.g., tank 46.
  • the effluent collection container e.g., tank 46.
  • This liquid is pumped" out by the action of the skimmer and is sent to the clarified effluent discharge.
  • the lug engages the switch limit 82 which actuates the solenoid-operated diversional valve 84 to divert the outflow from the skimmer to waste.
  • the position of the limit switch 92 is set such that this will be just before the mouth 52 of the skimmer 50 reaches the level A of sludge buildup-or approximately the level of the outermost end of the tube 62-so that all sludge is diverted to waste with none moving out to the clarified liquid discharge.
  • the skimmer drive means 56 drives the skimmer on to its outer limit of travel. As already indicated the proper limit is when the mouth 52 of the skimmer reaches a point about onequarter inch, more or less, from the inner face of wall 57 of the bowl.
  • the skimmer drive means 56 then reverses the travel of the skimmer. When the position of the skimmer is such on its leftward travel (FIG. 1) that the lug or trip 80 disengages the limit switch 82, the switch 82 will cause the solenoid-operated diversional valve 84 to divert the outflow from the skimmer back to the effluent.
  • the centrifuge embodying the invention is completely automatic in operation and operates on a sludge-level-sensing basis rather than on a time basis.
  • the time basis is fallible since the amount of solids in a given feed slurry may vary from time to time.
  • the present invention provides positive automatic means for precluding the passage of sludge into the clarified liquid effluent and does not rely on the presence of sludge in the effluent for actuation.
  • the present device is simple and virtually foolproof. Once it is set into initial operation it requires no operator.
  • peripheral bowl wall 57 may be perforated as in FIG. 4 to permit the flow of effluent therethrough while retaining solids, rather than discharging effluent over the overflow lip 32.
  • the electrical and fluid flow arrangements may be varied as well.
  • the valve 67 may optionally control flow of control liquid during sludge discharge, and skimmer drive means 56 may come from a wide range of motor means, electrical pneumatic, or hydraulic for example.
  • a variation of the present invention is the provision of a skimmer-type sensing tube, constructed and arranged similar to the feed tube 66 of the drawings but in addition thereto,
  • container as used herein includes any solids or any material which has a higher specific gravity than another material in the same feed mixture.
  • the invention has been described with reference to a preferred pressure-responsive switch 68 in the feed line 66, it is not so limited.
  • the invention may be practiced by employing other kinds of sensing means responsive to a change in at least one of the various flow characteristics of the control liquid in the feed line 66, including velocity and flow rate as well as pressure, for actuating the means fordischarging accumulations, e.g., solids, from the bowl.
  • the sensing means 68 is velocity responsive it will respond to a decrease in velocity of the control liquid in feed line 66.
  • the sensing means is responsive to flow rate of control liquid in the feed line 66 it will respond to a decrease in flow rate.
  • a still further modification contemplated by the present invention is radial adjustment of the nozzle 69 of the feed line 66 within the ring 60, also possible without shutting down the machine.
  • An adjustment toward a radial inward position delays the reaction of the sensing means 68 and therefore produces a larger solids accumulation before actuation of discharge, and again vice versa.
  • the skimmer tube 51 may be omitted. Instead, a radially movable knife or peeler may be substituted to discharge accumulated solids. However, this is not shown or described since the present invention is primarily directed to control apparatus in a centrifuge having any kind of device for discharging separated materials.
  • a centrifuge including a rotatably mounted, centrifuge bowl having means for feeding. into the bowl a flowable mixture of at least two materials wherein one material has a higher specific gravity than the other material and after centrifugal separation one material builds up against the peripheral wall of the bowl, means for discharging accumulations of said one material, means for continuously discharging the other material, and means for detecting the accumulation of said one material to predetermined level, said detecting means comprising structure defining an inwardly facing annular pocket mounted to rotate with the bowl, a passageway leading outwardly from the pocket generally toward the periphery of the bowl and terminating with an outermost opening of the passageway within the bowl outward of the annular pocket, means to supply a control liquid to the pocket, and sensing means to sense the buildup of control liquid in the pocket whereby when said one material reaches a predetermined level and obstructs said opening the control liquid builds up in the pocket, said sensing means being responsive to a change in at least one of the flow characteristics including pressure, velocity
  • sensing means is a pressure-responsive switch in said supply means responsive to an increase in pressure of said control liquid.
  • a centrifuge according to claim 1 wherein the supply means for the control liquid is tubular and has a discharge outlet disposed entirely within the pocket adapted to be immersed in accumulated control liquid within said pocket when the outennost opening of the passageway leading therefrom is obstructed by an accumulation of said one material.
  • a centrifuge according to claim 5 wherein the sensing means is a pressure-responsive switch in the supply means for the control liquid, which switch detects an increase in pressure in the tubular supply means resulting from the back pressure caused by the immersion of said discharge outlet in accumulated control liquid within said pocket.
  • a centrifuge according to claim 6 further including means for regulating the pressure of the control liquid in said supply means upstream of said switch.
  • centrifuge bowl is of imperforate construction with an overflow lip at one end thereof comprising said means for continuously .discharging the other material.
  • a centrifuge according to claim 1 wherein the means for discharging accumulations of said one material is a skimmer tube within said bowl movable in radial direction relative to the rotational axis of said bowl.
  • a centrifuge according to claim 14 further including a device for discharging material through said skimmer tube in one direction of flow during a first portion of outward radial movement of said tube and then in a second direction of flow during a second portion of outward radial movement of said tube, whereby said one material and said other material are separately discharged in the respective first and second directions of flow.

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US771156A 1968-10-28 1968-10-28 Control apparatus for centrifuge Expired - Lifetime US3595470A (en)

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US77115668A 1968-10-28 1968-10-28

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US (1) US3595470A (de)
DE (1) DE1947669A1 (de)
FR (1) FR2021740A1 (de)
GB (1) GB1291446A (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3703983A (en) * 1971-01-28 1972-11-28 Laval Separator Co De Method and apparatus for centrifuging fluid mixtures and selectively removing liquid material therefrom
US4761157A (en) * 1983-05-18 1988-08-02 Pennwalt Corporation Centrifuge apparatus
US5948271A (en) * 1995-12-01 1999-09-07 Baker Hughes Incorporated Method and apparatus for controlling and monitoring continuous feed centrifuge
EP1247584A2 (de) * 2001-04-05 2002-10-09 Fleetguard, Inc. Zentrifuge mit Sensor
US20070199907A1 (en) * 2003-09-30 2007-08-30 Mitchelson Keith R Apparatus And Method For Centrifugal Separation
US20090233780A1 (en) * 2006-04-28 2009-09-17 Gea Westfalia Separator Gmbh Separator with direct drive
US20110028296A1 (en) * 2009-07-29 2011-02-03 Edwin John William Zonneveld Bowl structure for a centrifugal separator
US20190151863A1 (en) * 2017-11-21 2019-05-23 Gyrogold, Llc Centrifuge separator for gold mining and recovery

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2532792A (en) * 1945-04-18 1950-12-05 Separator Ab Process for the centrifugal separation of sludge-containing liquids
US3011647A (en) * 1957-09-30 1961-12-05 Dorr Oliver Inc Centrifugal separator
US3052401A (en) * 1957-12-28 1962-09-04 Separator Ab Regulating device for centrifugal separators
US3167509A (en) * 1961-06-13 1965-01-26 Westfalia Separator Ag Centrifugal separator
US3261546A (en) * 1962-10-29 1966-07-19 Pfaudler Permutit Inc Method for clarifying fats and oils

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2532792A (en) * 1945-04-18 1950-12-05 Separator Ab Process for the centrifugal separation of sludge-containing liquids
US3011647A (en) * 1957-09-30 1961-12-05 Dorr Oliver Inc Centrifugal separator
US3052401A (en) * 1957-12-28 1962-09-04 Separator Ab Regulating device for centrifugal separators
US3167509A (en) * 1961-06-13 1965-01-26 Westfalia Separator Ag Centrifugal separator
US3261546A (en) * 1962-10-29 1966-07-19 Pfaudler Permutit Inc Method for clarifying fats and oils

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3703983A (en) * 1971-01-28 1972-11-28 Laval Separator Co De Method and apparatus for centrifuging fluid mixtures and selectively removing liquid material therefrom
US4761157A (en) * 1983-05-18 1988-08-02 Pennwalt Corporation Centrifuge apparatus
US5948271A (en) * 1995-12-01 1999-09-07 Baker Hughes Incorporated Method and apparatus for controlling and monitoring continuous feed centrifuge
US6143183A (en) * 1995-12-01 2000-11-07 Baker Hughes Incorporated Method and apparatus for controlling and monitoring continuous feed centrifuge
EP1247584A2 (de) * 2001-04-05 2002-10-09 Fleetguard, Inc. Zentrifuge mit Sensor
EP1247584A3 (de) * 2001-04-05 2002-11-06 Fleetguard, Inc. Zentrifuge mit Sensor
US6572523B2 (en) 2001-04-05 2003-06-03 Fleetguard, Inc. Centrifuge rotation indicator
US8033976B2 (en) * 2003-09-30 2011-10-11 Capitalbio Corporation Apparatus and method for centrifugal separation utilizing a movable collection assembly
US20070199907A1 (en) * 2003-09-30 2007-08-30 Mitchelson Keith R Apparatus And Method For Centrifugal Separation
US20090233780A1 (en) * 2006-04-28 2009-09-17 Gea Westfalia Separator Gmbh Separator with direct drive
US7850590B2 (en) * 2006-04-28 2010-12-14 Gea Westfalia Separator Gmbh Separator having a rigidly connected stator, an elastic support and ultra sockets
AU2007245667B2 (en) * 2006-04-28 2011-04-07 Gea Westfalia Separator Gmbh Separator with direct drive
US20110028296A1 (en) * 2009-07-29 2011-02-03 Edwin John William Zonneveld Bowl structure for a centrifugal separator
US8808155B2 (en) * 2009-07-29 2014-08-19 Flsmidth Inc. Centrifuge bowl with liner material molded on a frame
US20190151863A1 (en) * 2017-11-21 2019-05-23 Gyrogold, Llc Centrifuge separator for gold mining and recovery
US10695774B2 (en) * 2017-11-21 2020-06-30 Richard F Corbus Centrifuge separator for gold mining and recovery

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Publication number Publication date
DE1947669A1 (de) 1970-06-25
GB1291446A (en) 1972-10-04
FR2021740A1 (de) 1970-07-24

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