US3306444A - Hydrocyclone apparatus - Google Patents

Hydrocyclone apparatus Download PDF

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Publication number
US3306444A
US3306444A US464602A US46460265A US3306444A US 3306444 A US3306444 A US 3306444A US 464602 A US464602 A US 464602A US 46460265 A US46460265 A US 46460265A US 3306444 A US3306444 A US 3306444A
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United States
Prior art keywords
vortex
finder
mouth
diameter
oversize
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Expired - Lifetime
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US464602A
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English (en)
Inventor
Edwin P Troland
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Bird Machine Co Inc
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Bird Machine Co Inc
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Publication date
Application filed by Bird Machine Co Inc filed Critical Bird Machine Co Inc
Priority to US464602A priority Critical patent/US3306444A/en
Priority to FR65768A priority patent/FR1483525A/fr
Priority to FI661614A priority patent/FI49911C/fi
Application granted granted Critical
Publication of US3306444A publication Critical patent/US3306444A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04C—APPARATUS USING FREE VORTEX FLOW, e.g. CYCLONES
    • B04C5/00—Apparatus in which the axial direction of the vortex is reversed
    • B04C5/12—Construction of the overflow ducting, e.g. diffusing or spiral exits
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21D—TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
    • D21D5/00—Purification of the pulp suspension by mechanical means; Apparatus therefor
    • D21D5/18—Purification of the pulp suspension by mechanical means; Apparatus therefor with the aid of centrifugal force

Definitions

  • This invention relates to pulp cleaners, that is, apparatus for separating undesirable solid particles from fibrous suspensions, and more particularly concerns such apparatus of the hydrocyclone type which is capable of separating oversize fibrous particles from the desired fibres of the suspension.
  • the invention finds particular utility in the treatment of fibrous pulp suspension used in the manufacture of paper.
  • Vortex separators or hydrocyclones have long been used in the treatment of such suspensions to remove therefrom by centrifugal action the undesirable components which are of greater density than the desired fibres and are herein referred to as dirt.
  • Such separators normally comprise a tubular body, which may be conical, partially cylindrical, partially conical, or entirely cylindrical or nearly so, into which the suspension is tangentially fed under pressure adjacent one end thereof, the larger end in case of units which are all or partially conical.
  • the pressure normally 40 to 60 p.s.i., is such that the suspension forms an outer vortex whirling about the wall of the body with sufficient velocity so that under the centrifugal force developed the dirt collects as a relatively thin layer on the outside of the vortex and progresses toward the opposite end of the body where it is discharged through a small outlet.
  • the bulk of the suspension containing most of the fibrous material, reverses the direction of its axial movement as it progresses toward the end opposite the inlet, forming an inner vortex about an air core which returns from adjacent the dirt discharge outlet toward the inlet end where it is received and discharged through an outlet normally called a vortex finder.
  • Such apparatus has proved very effective and has been used extensively for removing dirt from such suspensions, but until recently such separators, particularly those of diameters under 1012 inches, have not been effective in removing from the suspension the oversize fibr'ous matter, which is of the same or substantially the same density as the desired fibres and so is not differentially subject to centrifugal force, being discharged together with the acceptable fibres from which it is later usually removed by screening.
  • oversize fibrous matter results from insufficient defibration of the pulpmaking material, e.g., chemical pulp, groundwood or repulped material, and may be overlong fibre bundles called shives or large, thin pieces of repulped material called flakes.
  • the amount of flow of suspension through the inner vortex finder and the percentage of the oversize fibrous matter it contains increase substantially as the ratio of the backpressure on the outer vortex discharge to that on the inner vortex discharge is increased.
  • the pressure ratio is increased the amount of acceptable fibre removed through the inner vortex finder increases substantially above a negligible amount.
  • the use of high backpressure may have an adverse eflect on the efficiency of dirt removal and the amount of good fibre lost with the dirt.
  • the object of this invention is to provide, in a hydrocyclone'of the type mentioned, a novel construction and arrangement of vortex finders which will greatly increase the effectiveness of the hydrocyclone for separating oversize fibrous matter from the acceptable fibre of a suspension.
  • the low end of the range previously mentioned I am able to more than double the percentage of oversize fibrous matter removed through the inner finder as compared with that removed with the prior arrangement, and even a greater percentage than that obtainable with the prior arrangement by increasing the backpressure difference to as much as 15 p.s.i.
  • the acceptable fibre removed through the inner vortex finder of my construction is negligible, and far less than with the prior construction operated at back pressure high enough to produce comparable oversize separation.
  • bafile must act to increase sharply those hydraulic forces of the vortex which act to segrespoon rs gate the oversize fibrous matter to the inside of the vortex without interfering with those forces which act to segregate the acceptable fibre to the outside of the vortex. It is known that the baffle does not act merely as a funnel. Tests in which the bafile around the inner vortex finder was replaced by a conical, funnel inlet of the same maximum inner diameter as the outer diameter of the baffie showed little, if any, improvement over the thin walled finder without baffie.
  • the inner vortex finder with its baffie according to the invention should project sufficiently beyond the mouth of the outer vortex finder so that the bafiie does not actually obstruct flow of the vortex into the outer finder but rather forces the outer part of the vortex to flow around it, outwardly and then inwardly before it is received in the outer finder.
  • the outer end of the baffle may taper somewhat in the axial direction of vortex flow outwardly of the inner vortex finder but not inwardly thereof sufficiently to constitute merely a funnel mouth for the finder which, as above noted, does not produce substantially improved results.
  • the width of the baffle in the radial direction of vortex flow is, of course, important and is closely related to the inner diameter of the mouth of the inner vortex finder which it surrounds. I have found that for effective action the baffle should have a width such that its diameter is within the range from about 1.5 to 2.25 times the inner diameter of the inner vortex finder.
  • the bafiie is formed as an enlargement of the inlet end of the inner vortex finder.
  • the 0.04 to 0.08 inch thick tubing normally employed for the finder would be thickened at its outer end or mouth to 0.25-0.75 inch.
  • This thickening is not carried back to the mouth of the outer vortex finder where it would constitute a major restriction of the inlet to that finder, but it may desirably be gradually diminished toward the mouth of that finder to provide streamlining which aids in producing smooth flow of the suspension around the baffie.
  • FIG. 1 is a side elevation, partially in longitudinal section, of a hydrocyclone embodying the invention
  • FIG. 2 is an enlarged transverse section view on line 2-2 of FIG. 1 looking in the direction of the arrows;
  • FIG. 3 is an enlarged longitudinal section view of parts of the apparatus shown in FIG. 1.
  • the hydrocyclone of the form selected for illustrating the invention has an elongated tubular body of circular cross section, which is cylindrical for about half its length and conical or tapering for the remainder.
  • an inlet 12 through which the fibrous suspension under pressure, usually 40 to 60 p.s.i., is fed tangentially to the cylindrical wall so that it flows spirally about. the wall toward the opposite end as an outer vortex.
  • the apex outlet indicated by the numeral 14 through which there is discharged a small fraction of the suspension consisting mainly of heavy particles or dirt" which are concentrated against the wall by centrifugal force of the outer vortex.
  • outer vortex finder 16 is similar in shape to the body 10, having a cylindrical portion 20 and a tapering or conical portion 22, the
  • apex end of which forms the open mouth of the finder At the end of cylindrical portion 20 opposite the conical portion 22 is a short conical portion 24 formed by the end of the body 10 from which an outlet pipe 26, containing a valve 28, conducts the acceptable fraction of the suspension to further processing, such as screening or direct discharge to the head box of a paper machine.
  • the inner vortex finder is a tube which is thin-i.e. of convention-a1 .04 to .08 inch thickness, at its mid portion which passes through the mouth of the outer vortex finder, but which is substantially thickened at its inner end to form a rigid supporting head 39 for the tube, and is likewise thickened at its outer end to form the baffle 32 opposed to the axial fiow of the vortex.
  • This finder is supported within the outer finder by means of rigid attaching wings 34, shown as three in number, which are welded or otherwise secured to the head 30 and to conical portion 22 of the outer finder.
  • An unobstructed passage 36 shown as of uniform diameter, extends axially through the inner vortex finder and connects at its inner end with an outlet pipe 38 of like inner diameter.
  • Pipe 38 extends at an angle to the axis of the body 10 through the end portion of the body to which it is secured and removes the fraction of the vortex received through the inner vortex finder. This fraction contains mostly the oversize fibrous matter and light particles plus air from the vortex core more or less broken up into bubbles, and may be sent on for further processing, such as recirculation to the defribrator, or may be discarded.
  • the thick head portion 30 and attaching wings 34 of the inner vortex finder impart rigidity which is important to prevent vibration or so-called buzzing of the inner finder which might otherwise occur and interfere with effective operation of the finder.
  • the expanding inlet to the outer vortex finder formed by conical portion '22 compensates for the thickening of portion 30 and also for such interference to flow in the outer vortex finder as is offered by wings 34.
  • the enlarged chamber formed by cylindrical portion 20 of the outer vortex finder permits continued vertical flow of the suspension about its wall with a minimum of interference from the portion of pipe 38 extending through the chamber.
  • the thin mid-portion of the inner finder imposes no reduction in the intake capacity of the two finders combined as compared with that of the outer finder alone without the inner one.
  • the bafiie 32 shown as formed by thickening the outer end of the inner finder 18, functions to increase substantially the percentage of oversize fibrous matter discharged through the inner vortex finder 18.
  • its outer or maximum diameter indicated at b in FIG. 3 should be between about 1.5 to 2.25 times the inner diameter a of the inlet to the inner vortex finder, and it should not substantially exceed the diameter of the mouth of the outer vortex finder.
  • the thickened portion 32 is streamlined in the direction of vortex flow, having a curved edge and diminishing in thickness gradually as the inlet to the outer vortex is approached, as is preferred to produce non-turbulent flow around it.
  • the baffled end of the inner vortex finder should project beyond the mouth of the outer vortex finder (distance 0, FIG. 3) at least A inch and preferably from 0.5 to 2.5 times the diameter of the inlet to the outer vortex finder.
  • the diameter a of the inlet to the inner vortex finder should be slightly larger than the air core of the vortex, and generally should not be less than %ths of an inch. This minimum diameter will generally be used in the smaller size units in which the maximum diameter of the body of the unit is in the range 2 to 4 inches, usually 3 to 4 inches. In the larger units, the diameter a may be somewhat greater, for example 0.5 to 0.8 inch in a hydrocyclone of 7 inch maximum diameter and 1 to 1.75 inch in a 12 inch diameter hydrocyclone.
  • the diameter of the inlet to the outer vortex finder is desirably about 2 times the diameter a.
  • the apex opening preferably has a diameter slightly smaller than diameter a and the inlet 12 has a diameter about equal to or less than that of the inlet to the outer vortex finder, or equivalent cross-section area if not cylindrical.
  • the body preferably has a length from inlet to apex outlet greater than 7 times its maximum diameter in order that the forces which produce the phenomenon of segregation between the oversize fibrous matter and the acceptable fibre in the inner vortex, on which the utility of the invention depends, have sutficient time to act completely before the vortex reaches the mouth of the inner vortex finder.
  • the vortex finders should not extend too far along the axis of the body 10, an axial length of the outer finder about equal to the maximum diameter of body 10 being desirable in most cases, with the inner finder projecting beyond the outer one to an extent previously mentioned.
  • the particular shape of outer vortex finder shown is desirable but not essential and it may, for example, be a cylindrical tube of uniform diameter.
  • bafile 32 need not be exactly flush with the mouth of the inner vortex finder as shown, but should be adjacent thereto. I have obtained good results with the end of the baffle located %ths inch back of the inlet to the inner vortex finder, such inlet constituted of the thin tubing of its mid portion extending Azths inch beyond the end of a batlle such as shown in FIG 3. For some reason I do not understand the combination of outer vortex finder and projecting baffled inner vortex finder according to this invention seems to operate more effectively when, as shown, located in a cylindrical end portion of a hydrocyclone body which is followed by a conical portion.
  • the ratio of the back pressure on the suspension flowing through the outer vortex finder to that on the suspension flowing through the inner finder is preferably controllable, as by valve 28, and maintained in the vicinity of about 5 to 1 psi. at which the selective segregating action of the bafile on the oversize fibrous matter appears to be about maximum.
  • the baflle 32 may have various other forms than the integral extension at the mouth of the inner vortex finder as shown. It may be located somewhat to the rear of the mouth of that finder as previously mentioned. It may be a wall of conical formation with its smaller end joined to the outer surface of the inner vortex finder sufiiciently spaced from its mouth so that the bafile does not extend substantially beyond the mouth. It may be a ring surrounding but spaced narrowly from the inner vortex finder, but in such case it is preferably supported from the inner vortex finder.
  • hydrocyclone apparatus capable of separating oversize fibrous matter from acceptable fibres of about the same density in a suspension thereof, said apparatus comprising an elongated tubular body, an inlet through which the suspension may be fed under pressure tangentially to the wall of said body adjacent an end thereof so that the suspension forms a vortex extending from adjacent one end to adjacent the opposite end of said body and immediately surrounding an air core, the length and velocity of flow of said vortex being such as to cause said oversize fibrous matter to segregate largely in the inner part of said vortex and the acceptable fibre to segregate largely in the outer part of said vortex during its flow, and inner and outer concentric vortex finders disposed axially in the path of said vortex to receive respectively said air core and an inner portion of said vortex containing mainly said oversize fibrous matter and light particles and the outer part of said vortex containing mainly said acceptable fibre, said vortex finders having separate outlets for separately discharging the vortex portions received by each, the improvement wherein said inner vortex finder projects axial
  • Apparatus according to claim 2 wherein said body has an outlet for dirt at its end opposite said inlet and safid vortex finders are located adjacent the inlet end there- 0 4.
  • Apparatus according to claim 3 wherein said apparatus has at least part of its body of conical form with said dirt outlet located at the apex thereof.
  • Apparatus according to claim 8 wherein the axial length of the outer vortex finder is approximately equal to the maximum diameter of said body.
  • said outer vortex finder has a conical portion the inner wall of which slopes outwardly from adjacent the mouth of said outer finder and said inner finder is attached to said sloping wall by spaced wings.
  • Apparatus according to claim 1 which includes means for regulating the backpressure on the flow through the outer vortex finder to an adjusted pressure of about five p.s.i. higher than the backpressure on the flow through the inner vortex finder.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Cyclones (AREA)
US464602A 1965-06-17 1965-06-17 Hydrocyclone apparatus Expired - Lifetime US3306444A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US464602A US3306444A (en) 1965-06-17 1965-06-17 Hydrocyclone apparatus
FR65768A FR1483525A (fr) 1965-06-17 1966-06-16 Appareil perfectionné du genre dit hydrocyclone
FI661614A FI49911C (fi) 1965-06-17 1966-06-17 Hydrosyklooni.

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Application Number Priority Date Filing Date Title
US464602A US3306444A (en) 1965-06-17 1965-06-17 Hydrocyclone apparatus

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US3306444A true US3306444A (en) 1967-02-28

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FI (1) FI49911C (enrdf_load_stackoverflow)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3472371A (en) * 1966-10-04 1969-10-14 Ronald Percy Ayerst Sorting fibrous material
US3486619A (en) * 1968-01-24 1969-12-30 Wikdahl Nils Anders Lennart Method of removing impurities from a fiber suspension
US4259180A (en) * 1976-05-14 1981-03-31 Enso-Gutzeit Osakeyhtio Hydrocyclone
US4473478A (en) * 1982-05-25 1984-09-25 Beloit Corporation Cyclone separators
US4605495A (en) * 1984-03-19 1986-08-12 Bird Machine Company, Inc. Hydrocyclone separator apparatus
US5466372A (en) * 1993-03-26 1995-11-14 J. M. Voith Gmbh Cyclone including an inlet diffuser tube
US6517733B1 (en) 2000-07-11 2003-02-11 Vermeer Manufacturing Company Continuous flow liquids/solids slurry cleaning, recycling and mixing system
US20120097280A1 (en) * 2009-05-08 2012-04-26 Watreco Ip Ab Vortex generator with vortex chamber

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2098608A (en) * 1935-03-22 1937-11-09 Berges Andre Apparatus for the purification of miscellaneous liquid mixtures
US2379411A (en) * 1937-07-11 1945-07-03 Berges Andre Method and apparatus for purifying paper pulp
US2724503A (en) * 1952-01-05 1955-11-22 Stamicarbon Hydrocyclone apparatus
US2756878A (en) * 1952-06-10 1956-07-31 Erie Mining Co Three product wet cyclone
US2816490A (en) * 1952-09-24 1957-12-17 Nichols Engineering And Res Co Apparatus for treating liquid mixtures for separation of solid particles and gases
US2981413A (en) * 1953-11-30 1961-04-25 Dorr Oliver Inc Process for separating solids in liquid suspension
US3101313A (en) * 1959-04-01 1963-08-20 Bauer Bros Co Hydro cyclone

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2098608A (en) * 1935-03-22 1937-11-09 Berges Andre Apparatus for the purification of miscellaneous liquid mixtures
US2379411A (en) * 1937-07-11 1945-07-03 Berges Andre Method and apparatus for purifying paper pulp
US2724503A (en) * 1952-01-05 1955-11-22 Stamicarbon Hydrocyclone apparatus
US2756878A (en) * 1952-06-10 1956-07-31 Erie Mining Co Three product wet cyclone
US2816490A (en) * 1952-09-24 1957-12-17 Nichols Engineering And Res Co Apparatus for treating liquid mixtures for separation of solid particles and gases
US2981413A (en) * 1953-11-30 1961-04-25 Dorr Oliver Inc Process for separating solids in liquid suspension
US3101313A (en) * 1959-04-01 1963-08-20 Bauer Bros Co Hydro cyclone

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3472371A (en) * 1966-10-04 1969-10-14 Ronald Percy Ayerst Sorting fibrous material
US3486619A (en) * 1968-01-24 1969-12-30 Wikdahl Nils Anders Lennart Method of removing impurities from a fiber suspension
US4259180A (en) * 1976-05-14 1981-03-31 Enso-Gutzeit Osakeyhtio Hydrocyclone
US4473478A (en) * 1982-05-25 1984-09-25 Beloit Corporation Cyclone separators
US4605495A (en) * 1984-03-19 1986-08-12 Bird Machine Company, Inc. Hydrocyclone separator apparatus
US5466372A (en) * 1993-03-26 1995-11-14 J. M. Voith Gmbh Cyclone including an inlet diffuser tube
US6517733B1 (en) 2000-07-11 2003-02-11 Vermeer Manufacturing Company Continuous flow liquids/solids slurry cleaning, recycling and mixing system
US20120097280A1 (en) * 2009-05-08 2012-04-26 Watreco Ip Ab Vortex generator with vortex chamber
US9243653B2 (en) * 2009-05-08 2016-01-26 Watreco Ip Ab Vortex generator with vortex chamber

Also Published As

Publication number Publication date
FI49911C (fi) 1975-11-10
FI49911B (enrdf_load_stackoverflow) 1975-07-31

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