CA1084450A - Hydrocyclone system including improved header- manifold arrangements - Google Patents
Hydrocyclone system including improved header- manifold arrangementsInfo
- Publication number
- CA1084450A CA1084450A CA326,851A CA326851A CA1084450A CA 1084450 A CA1084450 A CA 1084450A CA 326851 A CA326851 A CA 326851A CA 1084450 A CA1084450 A CA 1084450A
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- accept
- feed
- header
- wall
- suspension
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Abstract
ABSTRACT OF THE DISCLOSURE
Improved hydrocyclone separators are adapted for connection to an improved header having concentrically arranged feed and accept nipples. The hydrocyclone includes feeding means including unique guide vane means including a trans-ition section for swinging the feed suspension from a generally longitudinal direction to a generally spiral direction and accelerating same and connected to a helical section of constant lead within which a preliminary separation of the suspension is effected prior to feeding the suspension into the separation chamber. The accept outlet includes an elongated tubular member with the guide vanes being located in the annular region defined between the tubular member and the wall of the chamber. The wall of the separator chamber terminates at the large end thereof at an annular rim, the latter being connected to the feed nipple. The elongated tubular accept outlet has an end portion concentrically arranged relative to the annular rim of the separator chamber for connection to the accept nipple which is concentrically arranged relative to and within the feed nipple. The system operates efficiently at relatively low feed pressures, is simple in construction, easy to service and operate and can be arranged to occupy minimal floor space.
Improved hydrocyclone separators are adapted for connection to an improved header having concentrically arranged feed and accept nipples. The hydrocyclone includes feeding means including unique guide vane means including a trans-ition section for swinging the feed suspension from a generally longitudinal direction to a generally spiral direction and accelerating same and connected to a helical section of constant lead within which a preliminary separation of the suspension is effected prior to feeding the suspension into the separation chamber. The accept outlet includes an elongated tubular member with the guide vanes being located in the annular region defined between the tubular member and the wall of the chamber. The wall of the separator chamber terminates at the large end thereof at an annular rim, the latter being connected to the feed nipple. The elongated tubular accept outlet has an end portion concentrically arranged relative to the annular rim of the separator chamber for connection to the accept nipple which is concentrically arranged relative to and within the feed nipple. The system operates efficiently at relatively low feed pressures, is simple in construction, easy to service and operate and can be arranged to occupy minimal floor space.
Description
This is a divisional of application S.N. 270,494 filed Jan. 26, 1977. , This invention relates to improved methods , and apparatus for separating or fractionating liquid suspens~i~ns ' by means of hydrocyclones.
Hydrocyclones have been in use for a number of years in various fields as for example, the pulp and paper industry,and have been found useful for removing certain impurities, such as shives, bark, and grit, and other forms of dirt of a character unsuited for removal from the pulp by "~
screening processes.
', The overall construction and manner of ; operation of hydrocyclone separators is well known.' A typical hydrocyclone includes an elongated chamber ~e.g.conical) of circular cro~s-section which decreases in cross-sectional size '-from a large end to a small or apex end. A "reject" outlet '~
for the heavy fraction is provided at the apex of the con~cal chamber while the lighter or "accept" fraction of the suspension exits through an axially arranged accept outlet at the opposite ~' end of the conical chamber.- The pulp suspension is ïntroduced into the chamber via one or more tangentially directed inlets adjacent the large end of the chamber thereby to create a fluid vcrtex therein. The,centrifugal forces created by the ~Jortex -, throw the heavier particles of the suspension outwardly toward , the wall of the conical chamber thus causing a concentration of , solids adjacent thereto while the lighter particles are brought toward the center of the chamber and are carried along by an inwardly located helical stream which surrounds an axially disposed "air core n . The lighter fractions are thus carried outwardly through the accept outlet. The heavier particles continue to spiral along the interior wall of the hydr,ocyclone and eventually pass outwardly via the reject outlet.
The fluid velocities within the hydrocyclone ~ ' ., , ~
lS~44SO
are quite high and the dynamic forces thus produced are sufficiently high that gravitational forces usually have a negligibIe affect on the performance of the de~ice. Thus, the hydrocyclones may be oriented in various ways e.g. horizontally, vertically, or obliquely while maintaining satisfactory performance. The hydrocyclones are commonly arranged in large banks of several doze~ or even several hundred hydxocyclones with suita~le feed, accept, and reject headers or chambers arranged for cQmmu~ication with the feed, acce~t, and reject 10. openings respectively of the hydrocyclones.
Earlier separator systems involving large numberseaf hydrocyclone separators commonly employed a rather complex system of feed, accept, and reject pipes or conduits which, of necsssity, occupied-a very substantial amount of floor space a~d which required relatively costly and complex :
support structures for the relatively costly and complex piping ..
systems LnYolved. Furthermore, the piping systems involved -:
gave rise to.substantial fluid pressure losses,thus.requiring higher. feed pump operating.pressures which resulted in a
Hydrocyclones have been in use for a number of years in various fields as for example, the pulp and paper industry,and have been found useful for removing certain impurities, such as shives, bark, and grit, and other forms of dirt of a character unsuited for removal from the pulp by "~
screening processes.
', The overall construction and manner of ; operation of hydrocyclone separators is well known.' A typical hydrocyclone includes an elongated chamber ~e.g.conical) of circular cro~s-section which decreases in cross-sectional size '-from a large end to a small or apex end. A "reject" outlet '~
for the heavy fraction is provided at the apex of the con~cal chamber while the lighter or "accept" fraction of the suspension exits through an axially arranged accept outlet at the opposite ~' end of the conical chamber.- The pulp suspension is ïntroduced into the chamber via one or more tangentially directed inlets adjacent the large end of the chamber thereby to create a fluid vcrtex therein. The,centrifugal forces created by the ~Jortex -, throw the heavier particles of the suspension outwardly toward , the wall of the conical chamber thus causing a concentration of , solids adjacent thereto while the lighter particles are brought toward the center of the chamber and are carried along by an inwardly located helical stream which surrounds an axially disposed "air core n . The lighter fractions are thus carried outwardly through the accept outlet. The heavier particles continue to spiral along the interior wall of the hydr,ocyclone and eventually pass outwardly via the reject outlet.
The fluid velocities within the hydrocyclone ~ ' ., , ~
lS~44SO
are quite high and the dynamic forces thus produced are sufficiently high that gravitational forces usually have a negligibIe affect on the performance of the de~ice. Thus, the hydrocyclones may be oriented in various ways e.g. horizontally, vertically, or obliquely while maintaining satisfactory performance. The hydrocyclones are commonly arranged in large banks of several doze~ or even several hundred hydxocyclones with suita~le feed, accept, and reject headers or chambers arranged for cQmmu~ication with the feed, acce~t, and reject 10. openings respectively of the hydrocyclones.
Earlier separator systems involving large numberseaf hydrocyclone separators commonly employed a rather complex system of feed, accept, and reject pipes or conduits which, of necsssity, occupied-a very substantial amount of floor space a~d which required relatively costly and complex :
support structures for the relatively costly and complex piping ..
systems LnYolved. Furthermore, the piping systems involved -:
gave rise to.substantial fluid pressure losses,thus.requiring higher. feed pump operating.pressures which resulted in a
2~ relatively high ccnsumption of energy during operation of the :~
systems.
In an effort to alle~iate a number of these :~:
pro~lems, certain innovators, such as Wi~dahl in Sweden, developed circular canister arrangements containing multiple .
hydrocyclones. The hydrocyclones were supported in vertically spaced apart layers, with the hydrocyclones of each layer being disposed in radially arranged arrays with common feed, accept, and reject cham~ers c~mmunicating with the hydrocyclones in the several layers. One basic object of this arrange~er.t was :
to save on the floor space area required for the hydrocyclones above the equipment floor while the feed, accept and reject collection piping was installed beneath the floor together with the necessary Yalves on each unit for adjusting pressures and for isolating individual "canisters" . This form of system did save space but there were a number of disadvantages in t~at the operation of individual hydrocyclones could not be observed;
thus, if one or more hydrocyclones became plugged during operation, the operator had no way of detec~ing such plugging until the ef~iciency of the entire unit was decreased sufficiently as to call for a shut-down of that unit and disassembly of same thereby to allow the defective hydrocyclones to be removed and replacsd. Furthermore, access to the various valves and pressure gauges for each uni~ was awkward because they were all located under the equipment floor and a special walXway was required under the ~lo~r to enable the operator to have access to such valves and gauges. These systems were also operated with reject pressures above atmospheric and it was requiFed that they be adjusted with accuracy in order to control the operation of the cleaner since the cleaners are very sensitive to the difference in pressure between the accept and reject openings.
2~ More recently, alternative forms of modular hydroc~clyone separator systems have been devised in an effort to overcome the above noted problems with the '~canistern system.
These new systems involve vertically disposed,suitably spaced feed, accept, and re~ect headers. The individual hydrocyclones are connected to these headers and are positioned in generally vertical planes in su~stantially horizontal positions, one above the other. Thus, operator control of the cleaning system is facilitated and the operation of individual hydrocyclones cant be obser~ed. ~owever, while the above noted "canister" systems did permit operation at reduced feea pressures due to ths elimination of some of the pressure losses caused by the feed piping arrang2ments of conventional systems, the above noted .. . - :
modular system emp~oying vertically disposed,separate accept, feed,and reject headers,still suffers from the dïsad~antages inherent in the older systems insofar as pressure losses are concerned. ~he hydrocyclones used with these systems all employ a single tangential feed entry and, in common with the older prior art systems, have a built-in pressure loss at the poi~t where the feed st~c~ turns from the feed header into the indi~idual feed inlet pipes for each hydrocyclone, and also along the length-~ of the feed inlet pipesj an~ als~-on entry into the geparation chambers of the individuai hydroCY~lnes-In aadition, there is a loss of pressure at the points where the accept stock from the hydrocyclones enters the accept header frGm the accept pipes associated with each hydrocyclone. Thus, in order to obtain the cleaning efficiency desired, these later forms of modula~ cleaning systems, in common with the earliest systems, typically require stoc~ feed pressures in the feed header in the order of 4~ pounds per square inch gauge, whereas the above noted canister systems required feed pressures of much lower magnitude since they did not require the complex ~;
2~ fe~d inlet pipes for each indiviaual hydrocyclone as in the o~her systems noted above.
It is a general object ~f the present invention to provide improve~ents in hydrocyclones and in hydrocyclone systems, which incorporate the advantages noted above in connection with the later forms of modular cleaning systems as well as providin~ the low pressure operating characteristics inherent in the "canister" cleaning systems.
Th~ present lnvention thus involves, among other things, improved hydrocyclone separators per se, -particularly improvements in the feed and accept regions of same and improved methods of separating suspensions in such hydro-cyclone separators as claimed in parent application S.N. 270,494.
., . ,~.. _. ..... .... . . . .. . .. .
The present divisional particularly concerns improvements in cleaning systems including a novel form of feed and accept header arrangement for supplying groups of such hydrocyclones.
Thus,the present invention in one aspect provides a cleaning system for liquid suspensions comprising an elongated combination feed and accept header having a plurality of hydrocyclone separators detachably connected thereto and projecting laterally outwardly from said header in spaced apart relation therealong, each said hydrocyclone separator including an elongated separator chamber having a large end and an oppositely disposed small end with a reject outlet therein, the large end of the separator chamber having an annular wall, and a tubular outlet for accept material disposed at said large end in concentric relation to said annular wall, with a sub- ~
stantially full annular inlet for feed suspension into said -.
separator chamber being defined between said annular wall and the tubular accept outlet, and guide vane means being-located in said annuiar inlet between said annular wall and said tubular accept outlet, said guide vane means being adapted to cause the feed suspension flowing through said annular inlet toward the separator chamber to move in a spiral path whereby to set up a fluid vor~ex in the separator chamber; said feed and accept header including an outer wall and a dividing wall therein to separate a flow of feed suspension from a flow of accept suspension in said header; a plurality of tubular accept nipples connected to said .
dividing wall in aligned spaced apart relation for fluid flow there-through and each of said accept nipples being sealingly detachably connected to a respective one of the tubular accept outlets of the hydrocyclone separators; a corresponding plurality of tubular feed nipples each surrounding a respective one of said accept nipples in spaced concentric relation therewith and being connected , 1~44SO
to said outer wall of the feed and accept header for fluid flow theréthrough and each of said tubular feed nipples being sealingly detachably connected to a respective one of the annular wall portions at the large ends of the respective hydrocyclone separators, whereby feed suspension from said header can pass ;
toward the separator chambers of the hydrocyclones through the annular inlets defined between said concentrically arranged feed ;~
and accept nipples while permitting accept suspension to pass from each separator chamber through said connected tubular accept outlets and accept nipples and thence through said dividing wall to join the flow of accept suspension in said header.
In a further aspect the system includes an elongated xejects header disposed in spaced generally parallel relationship to the feed and accept header, and the respective reject outlets of said separators being adapted to discharge to the rejects he'ader.
The individual hydrocyclone separators can be easily r~moved from the header system for repair and/or replacement.
In a preferred form of the invention said annular wall portion of each hydrocyclone separator defines an annular seat thereon which sealingly engages with its associated feed nipple of the header.
In accordance with a further feature of the invention, both said annular seatand said feed nipple have radially outwardly -extending co-operating annular lips thereon, and a clamping means engaging said lips and securing the hydrocyclone chamber to the feed nipple, and the tubular accept nipple being in mating telescoped relation to the associated tubular accept outlet of the hydrocyclone.
In a further feature said outer wall of the feed and accept header comprises a relatively large diameter pipe and said dividing wall comprises a plate separating the interior of the pipe into two regions.
As an additional feature, said outer wall of the feed and accept header comprises a relatively large diameter pipe and said inner wall is in the form of a pipe located within the outer pipe and spaced therefrom in the radial direction to allow for the flow of the feed suspension therebetween.
10In a preferred form of the invention, there are provided support frame members extending between the feed and accept header and the rejects header for stabilizing the latter, the headers, support frame members and the hydrocyclone separators all lying substantially parallel to a common -vertical plane.
In a further feature of the invention both of said headers are arranged in a generally upstanding position with the hydrocyclone separators extending therebetween being slightly inclined from the horizontal so as to permit virtually all suspension to drain from the system after shut-down.
The principles of the invention and the advantages associated therewith will be better understood from the following description of preferred embodiments of same with reference being had to the drawings wherein:
Figure 1 is a view, partly in section, of a hydrocyclone separator in accordance with the invention and connected to a combined feed and accept header arrangement in accordance with a further feature of the invention;
Figure 2 is a longitudinal section view of the .~
10~44S0 inlet feed portion of the hydrocyclone in acc~rdance with the invention and illustrating the manner of connection of same to the combined feed and accept header arrangement;
Figure 3 is an end elevation view of the com~ined accept outlet and guide vane arrangement;
Figure 4 is a view similar to Fig. 3 but showing the opposite end of the combined accept outlet and guide vane arrangement;
Figure 5 is a section view illustrating details of the guide vane arrangement in the helical section ~ -thereof;
Figure 6 is a longitudinal section view of one form of c~mhined feed and acc~pt header arrangement;
Figure 7 is a cross-section ~iew taken along line 7- 7 of Pi~. 6 and looking in the direction of the arrows;
Figure 8 is a longitudinal section view of a fuxt~er for~ of com~ined feed and accept header arrangement;
Figuse 9 is a cross-se¢tion view taXen along line 9-9 of Fig. 8 and looking in the direction of the arrows;
Figure 10 is a side elevation view of a mcdular cleaning system L~ lustrating a series of hydrocyclone separators in accordance with the invention and connected to a combined feed and accept header arrangement and also to a the reject header arrangement;
Figure 11 is a section view taken along line 11-11 of Fig. 10 a~d looking in the direction of the arrows.
With reference now to the drawings there is shown at Figure 1 typical hydrocyclone assemblies 20 connected to a combined feed and accept header 22. The hydrocyclone 20 includes a wa~l 24 defining an elongated chamber of generally circular cross-section. This wall includes a ' ' . . : . ' ': . , ' ' . -. , ' ' ~ ' . ' ~ ' . ,' . ' , ' ~084450 generally cylindrical section 26 defining the large end of the hydrocyclone,which cylindrical wall portion is connected to . ~ -a conical wall portion 28 which tapers generally uniformly down to reject outlet 30 at the apex of the conical.portion, such reject outlet being defined by a tip portion 32. The wall o~ t~e reject outlet passage is preCerably~ but not necessarily, ~:
provided with spiral groove defining means of the type illustrated .
in ~.S. patent 3,800,946 dated April 2, 1974 and assigned to ~ -the assignee of the present in~ention.
L0 An acrept outlet and guide vane arrangement 34 ~s located.withln the large end of the hydrocyclone , i-e-within the cylindrical section 26 thereof. That portion of the elongated chamber within which assembly 34 is located is termed the inlet section of the chamber. That portion of the hydrocylone chamber intermediate the inlet section of the -.
chamber and the apex or tip portion 32 i5 termed the separation :.
chamber. This assembly 34 communicates with an accept nipple .
36 forming part of the feed and accept header 22 while the wall of the hydrocylone 24 is connected at the large end there-of to a feed nipple 38 also forming a part of the above mentioned feed and accept header 22. A more detailed descrip- :
tion of suitable forms of feed and accept headers in accordance with the invention will follow hereinafter. .
The accept outlet and guide vane assembly 34 is adapted to introduce feed suspension generally tangentially into the separation chamber defined by wall 24 thereby to provide a high velocity fluid vortex within such chamber with the heavier portions of the suspension passing downwardly and ~ around the wall of the chamber and ultimately passing out of the reject outlet 30. The lighter fractions of the suspension move toward the axis of the separation chamber and join an oppositely moving helical flow which surrounds an air core 44~0 passing along the hydrocylone axis ~ith such lighter fractions ~;
utlimately paSsing outwardly of the hydrocylQne through the above noted accept conduit 36. ' With reference now to Figures 2-5, àt will be seen that the accept outlet and guide vane assembly 34 i5 disposed in the inlet section of the elongated chamber at the large end of the hydro~yclone separator 20 and ~ithin the cylindrical wall portion 26 thereof. The assembly 34 includes an elongated tubular member 40 having a pair of guide vanes 42 extending outwardly therefrom, with such guide vanes 42 being located in the annular space defined between tubular member 40 and the interior wall 45 of the inlet section of the elongated chamber.
The outermost edges of the guide ~anes 42 contact the inner wall 45 of the inlet section of the chamber thereby to prevent by-pass of fluid therebetween. The assembly 34 is maintained in position within the hydroclone chamber by means of pro-jections 35 formed on the outer extremity of each vane 42, which projections seat in corresponding recesses formed in the wall of the chamber at the large end thereof.
The two guide vanes 42 each include two sections i.e.
a transition section having a length Lt as shown in Fig. 2 for gradually swinging the suspension from a generally longitudinal -direction to a generally spiral direction while gradually accelerating the suspension, and a helical section having a length Lh as shown in Figure 2 arranged to cause the suspension to rotate around the chamber axis in the inlet , section to impart centrifugal forces thereto prior to feeding the suspension into the separation chamber.
With continued reference to Fig. 2 it wil~ be seen that the two guide vanes 42 are disposed at a rela-lively shallow angle e.g. 10 to the axis of the separator at the -inlet end thereof with such angle gradually increasing _ 10-.
10l~44S0 to an angle of about 84 at the end of the transition section. The channels defined by the guide vanes 42 are initially of relati~ely large cross-sectional area.
The guide vanes interfere in only a very minor way with the flow of the fluid. Since the two channels are of relatively lasge cross-section, a relatively low fluid velocity at the entry to the channels is maintained. ~he inlet vane angle of ~ ~ -about lO~ is considered reasonable fcr negligible pressure loss and, in this way, the axial length Lt of the transition section is maintained within reasonable l~mits. Furthermore, in the transition section, because o~ the change in the angles which the guide vanes 42 m~e with the a~;s of the separator, there is a gradual decrease in ~he cross-sectional area of such channels along the length thereof. This gradual reduction in cross-section and the gradual change of angle of the guide vanes 42 results in a transition from what is initially essent-ially axial flow to flow that is essentially in a spiral direct-ion. This transitition in f low direction and the acceleration of the fluid are achieved in a relatively smooth fashion thereby reducing friction and shock pressure losses.
Following the transition section, the suspension smoothly enters the helical section referred to above. In this section the guide vanes 42 are at a constant angle to the axis of the separator and are hence of constant lead in the same sense as used in relation to a screw thread and define flow channels of substantially constant cross-sectional area along the length of same. This cross-sectional area is of course measured at right a~gles to the direction of the flow.
The helical section is of sufficient length as to carry the fluid in each of the channels around the hydrocylone axis by a substantial distance, preferably about one full revolution thus tending to develop a free vortex pattern in the suspension 10~44SO ~-which had been previously accelerated in the transition channels. This rotational motion of the fluid provides for some separation or cleaning of the suspension under the in- -fluence of centrifugal and shearing forces so that on enter-ing the separation chamber larger particles have been pre- ~
ferentially vortexed outwardly toward the wall 45 of the ~ ' chamber thus reducing their potential for "short circuit" ''' flow down the outside and around the end of the vortex ~, finder 44, the latter extending downwardly into the separation ~ -chamber for a desired ~istance beyond the terminal portion of the he7ical section of the guide vanes 42. By reducing the tendency for "short circuit" flow to occur, cleaning efficiency ,,'~
is increased.
With reference to Figure 4, which illustrates the exit portions 46 and 48 of the two channels formed by the guide vanes 42, it will be seen that the stock makes entry into the separation chamber from the inlet section across the full width of the annular space be~ween the tubular vortex finder 44 and the interior wall of the elongated chamber. This full annular entry is advantageous because:
(1) It further reduces the tendency for nshort circuit" ,-flow. (In conventional hydrocyclones wherein the fluid enters tangentially through one or more inlets in the side wall of the hydrocyclone, it has been shown that the stationary roof or top of the co~ventional hydrocyclone creates an obstruction to , tangential flow with this obstruction causing a portion of the feed liquid to pass directly acro'ss the cyclone roof and down the outsi~e wall of the vortex finder to join the accept flow with_n the vortex finder). By providing full annular entry, '' the "stationary roof" effect is substan~ially''eliminated.
12) the full annular entry also reduces shoc~ losses of _ 12 _ .. . . ... .. ...
1~84450 fluid on entering the separation chamber. In conventional hydrocyclones,shoc~ losses occur as the result of the meeting of two flow streams having different velocity distribution.s ,, i.e. the flow stream entering through the tangential inlet ' and the flaw stream provided by the vortexing liquid within , the chamber. With the present arrangement all of the fluid ;, entering the separation chamber is already in rotation and ;: is almost in a fully developed free vortex pattern and, thu~s, '~, since it occupies the entire annular space between the vortex fi~der and the inside wall 45 of the separation chamber there ' will be mini~al flow-disturbance as it attains a fully developed free vortex-forced ~ortex patter~ in the separation chamber.
It will also be noted with reference to .~ Figures 3 and 4 that the opposed guide vanes 42 are not exactly diametrically opposed i.e. they are off-set slightly fr diametral positions by a smzll angular amount which preferably ~ is in the order of 5 or somewhat more. While this slightly ,~ offset arrangement is by no means essential, the slightly off-set rangeme~t shown is belie~ed to possess certain advantages in that the feed pumps which feed the hydrocyclone usually tend ' to set up a small amount of pulsation in the fluid-entering the hydrocyclone. If the channels defined by guide vanes 42 are ' exactly-symmetrically arranged with the discharges 46 and 48 '~ .thereof in diametric symmetry, the resulting pulse at entry to the hydrocyclone will have the amplitudes of thése fluid pulses.
~y arranging for the flow channels to be slightly asymmetric as shown in the drawings, the total pulsations so formed by the existence of these two pulsations will be decreased because they ,will be,out of phase with one another and consequently the .
`~ 30 total amount of vibration of a bank of such hydrocyclones will ;
: _ 13 _ , : ;
11)~44SO -ba reduced somewhat.
With further reference to the accept outlet and guide vane assembly 34, it will be seen that the tubular portion 40 thereof includes a portion 50 extending out~ardly of the large .:~
end of the hydrocylone and providing a means fQr connection to ..
the acc:ept nipple. 36 noted above. As sho~n in ~igure 2, in order to permit the accept nipple 36 to seat within the end ; . -of this tubular portion 50, the latter includes a radially '~ outwardly stepped portion 52 with. an annular groove 54 therein which serves to contain a resilient O-ring gasket thereby preventing leakage of fluids between tubular portion 50 of - -the accept outlet and the accept nipple. 36.
The wall 26 of the elongated chamber terminates at . the large end thereof at an annular rim 60, the annular rim .-defining an annular seat 62 thereon adapted to sealingly engage :
with a similar form of rim on the feed nipple 38. This annular rim 60 includes a radially outwardly extending lip 64 thereby to enable the elongated chamber to be connected to the feed :
nipple. 38 by means of a conventional V-band clamp 66. The . .
2Q wall 26 of the chamber is also radially outwardly stepped at 67 thereby to permit the extreme end of the feed conduit 38 to fit snugly therein.
Typical forms of combination feed and accept headers are shown in Figures 6-9. With reference to Figures 6 and 7 it will be seen that the feed and accept header 22a includes -.:
a cylindrical outer wall 70 having a divider wall 72 disposed therein thereby to provide for separation between the accept region 74 and the feed region 76. A plurality of tubular accept nipples 36a are connected to the dividing wall 72 in aligned spaced apart relation for fluid flaw therethroush w~ h such accept nipples 36a being adapted for connection to the respective end portions 50 of the t.ubular accept outlets of ~L0844SO
a series of hydrocylone separators in the manner illustrated in Fig. 2. A corresponding plurality of tubular feed nipples 38a are provided each surrounding a respective one of the accept nipples 38a in spaced concentric relation therewith, with each feed nipple 38a being connected to the cylindrical outer wall 70 for fluid flow therethrough. The terminal end portions of the feed nipples 38a are provided with annular rim portions 78 adapted to cooperate with the annular rim portions 64 of the hydrocyclone separator described above in connection with Figure 2 thereby to enable the respective separators to be connected thereto by V-band clamps 66 as described above.
The ~eéd ~uspension is supplied to the feed . .
region 76 of the header by way of a feed inlet 80 which is also connected to the wall 72,while the accept suspension exits by way of a tubular outlet 82 connected to cylindrical wall 70.
It will be appreciated that the assem~ly shcwn in Figures 6 and 7 can be made of any desired length thereby to accommodate any desired number of hydrocyclones.
The embodiment shown in Figures 8 and 9 is very much the same in principle as the embodiment of ~igures 6 , and 7 except that the inner dividing wall is in the form of an elongated pipe 72b of circular cross-section with the outer ~;lall 70b being in the form of a relatively large diameter pipe surrounding the inner pipe 72b. Thus, the feed suspension passes along the annular space provided between the outer pipe 70b and inner pipe 72b. The individual tubular ;~ feed nipples 38b are connected in spaced apart relationship to the outer pipe 70b while the individual accept nipples 36b are connected in spaced apart relationship to the inner pipe i 72b. One end of the inner pipe 72b is provided ~ith a flanged connection 84 for connection to a suitable accept header (not ' ~ - 15 -shown) while the outér pipe 70b is pn~nded with a f~nged ~ne ~ on 86 for o~ec ;on to a sul ~ le feed he ~ r (not ~n).
The header assembly illustrated i~ Fig. i and referred to previously is very similar to the one shown in Figs. 6 and 7 except that it makes provision for the connection thereto of two spaced parallel rows of hydro-cyclone separators.
By virtue of the above described arrangements,the feed suspension enters the inlet region of the individual ~ydrocyclones fr~m the feod region of the com~ined feed-accept header with a relatively low pressure loss due to the relatively large size of the inlet. The combined feed-accept header is sized such that the fluid velocities therein are relatively low and, by virtue cf the fact th-t the feed stoc~
enters the hydrocyclone through the relati~ely large annular area between the accept nipple 36a and the feed nipple 3~a, relatively low fluid velocities are maintained thus resulti~g in negligible pressure losses since such pressure losses are proportional to the sguare of the fluid velocity. The friction and shock losses inherent i~ conventional syst~ms are very significantly reduced when using tAe apparat~s as described abo~e, thus enabling the cleaning systems of the in~ention to operate at relatively low feed pressures.
A typical modular pulp stoc~ cleaning syste~
employing a combinea feed-accept header arrangement and hydrocyclones according to the present invention is illustrated in Figures 10 and 11. The header arrangement 22b is of the type illustrated in Figures 8 and 9. It will be seen fr~m Figure 10 that the feed-accept header 22b is located in a generally upright position but is inclined slightly from the vertical e.g. by an angle of about 5. Also provided, in spaced parallel relationship to the header 22b,is a reject header 90.
A plurality of hydrocyclone separators 20 are connected between _ 16 _ - 1~184450 the heade~s 22b and 90 in vertically spaced apart relationship i.e. the separators are disposed one above the other in a generally vertica plane. The longitudinal axes of the hydrocyclone separators 20 are also inclined from the horizontal by about 5 thus allowing suspension to drain therefrom when the equipment i~ shut down.
The individual separators 20 are connected to the--feed-accept he~der-22b-by means-of-V-band-clamps 66 as-described above. The opposing reject end portions-of the separator are connected to the reject header 90 via a transparent si~ht glass 92 a~d a tubular adapter member 94. Thus, the rejact flows from the separators 20 can easily be observed.
~ he above noted assem~ly is provided with a simple support frame 100 includi~g upright legs 102 connecte~
at their upper end to horizontally extending frame members 104, the latter being interconnected between the header 2Zb and the header 90 The upper ends of the aboYe two headers are also interconnected by means of horizor,tally extending frame members lOo. The separators 20 are additionally supported by means of a generally upright frame member 108 extending between frame members 104 and 106, frame member 108 having a series of angularly arranged plates 110 (see Fig. 11) welded thereto in ~paced apart relationship with such plates 110 serving to su~oort therebetween the cyclone separators 20.
The above noted frame 100 is suitably welded together and is provided with the necessary cross-members, bracing members etc., none of which need tc be described here.
The feed-accept header 22b is connected to a pipe 114 which supplies feed stoc~ thereto via a vertically ~isposed pipe 116 extending upwardly through the floor. A
control valve 118 i~ disposed in the feed line in conventional - manner. The accept flow passes outwardl~ of header 22b via -17 ~
844s0 pipe 120 and passes downwardly through a vertical pipe 122 which extends through the equipment floor. A sui~able control valve 124,is also provided in this line in conventio~al fashion. The reject flow frcm header 90 also passes downwardly through a vertically disposed pipe 126~
In practice, two such modular assemblies as sh~wn in Figure 10 are placed close toge~her in side-by-side ralationship. The amount of floor space occupied by such an :. - - .
arrangement is relatively small and the operator has ready 1~- access to the feed and accept control valves 118 and 124 for each~-assembly. On shut-down of the assem~ly, both the feed-accept header 22b and the separators 20 have an opportunity to drai~
cQmpletely thus eliminating problems of stock remaining in the system and subsequently drying up thereby producing lumps of stock which can cause a problem later on at start-up.
The system shown in Figures 10 and 11 is also ~ery easy to ser~ice. The individual hydrocyclone separators 2~ are clamped to the header 22b by means of simple V-~and . .; .
clamps 66 which permit the hydrocyclones to be quickly removed ; 2~ for servicing~ The structure as a whole is relatively simple in construction and employ~ a minimum of piping and connections Y thus making the arrangement less expensive ~or the manufacturer ~ to build.
~.; .
~i ~eturni~g now to the hydrocyclone separator per se, Tables 1 and 2 which follow outline test aata obtained ~ for a typical hydrocyclone in accordance with the present !~.' invention (designated by the ~odel number ELP-440) in comparison with the test data obtained for a conventional hydrocyclone odel EIP-420), the latter having the same overall dimensions .;- .
` 30 as the ELP-440 Model, but being provided with a conventional single tangential inlet provided in the wall of the hydrocyclone adjacent the large end thereof and being connected to a ,~ conventional feed and accept header system.
_ 18 _ ;: .
.:..... .. . . . . .. . . . .. .. ... .
? 1~445() ?
The ETP-440 Model in accordance with the invention had the following dimensions, reference being had to Figs. 1, 2 and 5:
TABIE OF DlMENSIONS (ELP~40) .. . .. ... ..... .... ... . . . . .. .... .... ....
(a) Dimensions of Fee'd and Accept Arran~ement Ll-(guide vane section length)=9.50 in.
Lt=(vane transition sectio~ length)=7.00 in.
~3 (~ane helical section length)=2.50 in.
L2-(accept outlet extension length)= 3.0~ ~n.
L3- (vortex finder length) ~ 3.00 in.
~1- (maximum inside diameter of accept~ = 2.35 in.
D2- (maximum outside diameter of accept) = 3.50 in.
D3- (Spiral feed vane diameter) = 6.00 in.
= (inside top cone diameter(D6) D4- (minimum inside diameter of vortex finder)= 2.00 in.
D5- (minimum outside diameter of vortex finder)=2.50 in.
(b) Guide ~ane Dimensions Tl - (space at ~ane edge(helical sect.)=0.55 in.
T2 - (~ane thickness at outer edge) = 0.30 in.
T3 - (vane lead in helical section) = 1.70 in.
T4 - (~ane radial width(max.)) - 1.63 in.
(decreases to 1.25 in. at point B) T5 - (vane root dLmension(average) = 0.43 in.
(in lower helical section only) - (va~e taper angle)= 2 - (an71e of guide vane to axis of separator at point B)= 10 (this angle increases gradually to about 84 at end of transition section) (c~ Overall Dimensions of Separator ~ .
L4 -(length of cylindrical section) = 25 ins.
~ - 51ength of conical section includins tip)=34 ins.
~ g , .. . .. .
i~l844SO
. . . .
C~ - (cone included angle) = 9 D7 - (inside diameter of reject outlet tip) = 5/8 in.
~this may ~ary depending on circumstances) The test results are gi~en in the following -Tables 1, 2 and 3. :.
.... . . . .. ... . .. .. . ..
~EST RESULTS - PROTOTYP~ ELP-440 ... ...
.. ...... Efflciency 440 vs 420 Tert'y Bleachèd Softwood Kraft Pulp ~ eed Tempe~ at~re 55C .
Cleaner Test!Pressures (psig) Feed Stock % Dirt Counts Model Codel _ DP Capacity Cons'y Reject SPecks/GM
No. !Feed Acc F~A USGPM-- %OD Feed Rate Feed Reject 440 1 135 10 25 liO .316 29. 9 13 48 440 2 130 10 20 126 . 305 30.6 10 56 440 3 !2s lo 1S 106 .310 32.3 10 43 420 8 40 6 34 120 .300 28.0 9 31 420 9 35 5 1/2 29 1~2 114.319 21. 6 N.M. N.M.
420 10 40 10 30 113 .313 60.g 10 Z3 . Efficiency 440 vs 420 Primary Unbleached Ammonia-Based Sulphite Pulp Temp = 21C.
ELP-440 and ELP-420 Tested Simultaneously Compare Tests l~l,lA&lA,e r !Cleaner Test Pres~ 'ures ~psig) Feed Stock % Dirt Removal Model. Code . DP Capacity Cons ' y ~ej ect Ef ficiency , No. Feed Acc F/A USGPM %OD Feed R2te -DF-DA x 100 _ 440: 1 24 10 14112.5 0.575 11.8 65 : 440 2 26 12 14113.5 0.423 15.7 . 60 ...
420 1 34 6.5 27.5100.9 0.575 14.4 65 420 2 34 - 6.5 27.5101.8 0.423 15.3 58 = _ 440 lA 24 10 14113.0 .578 10.9 56 440 2A 20 10 1096.4 .597 13.4 43 .
420 lA 34 6.5 27.510~.4 .578 6.8 44 420 2A 34 B.5 25.596.9 597 16.8 52 .
.
_ 20 _ . ~, , . , , . ~ . .
.
. Performance ELP 440 Secondary Bleach~ ~d ~ardwooF L Rraft Pulp Temperature.=llZ~ F~;.
Pressures (psig) Feed Feed %. . Dirt Coun~s %Eff'y=
Feed Acc D~ Capacity Cons'y Reject (7 ~and (sP/gm) DF-DA
F/A USG~M ~OD Rate Sheets. 1.5 qmea. DF x~n F~eFd ADAept "
. . . ~
24 . 10 .14 111.6 0.68 17.8 12.89 4.11 68 22 8 14 112.5 0.71 13.5 12.56 2.46 80 6 14 111.9 0.72 10.6 1 ~ 2.81 76 It will be noted from Tables 1 and 2 that the feed to accept differential pressure required for the EIR-440 in accordance with the invention was only about 1/2 of the differential required for the EL2-420. At the same tIme the ELP-440 achieved similar feed capacities a~d similar dirt re~oval efficiencies as compared with the ELP-420. Thus, the very significant reduction in differential pressure required by ~he a~ove cleaner represents a very significant saving in .; the overall energy used for the cleaning of pulp stock. Similar -'` savings in energy are anticipated in connection with the separl~tiDg o~ otDer types of susp-nsioDs~ :
: 30 , :
, .. . . .
systems.
In an effort to alle~iate a number of these :~:
pro~lems, certain innovators, such as Wi~dahl in Sweden, developed circular canister arrangements containing multiple .
hydrocyclones. The hydrocyclones were supported in vertically spaced apart layers, with the hydrocyclones of each layer being disposed in radially arranged arrays with common feed, accept, and reject cham~ers c~mmunicating with the hydrocyclones in the several layers. One basic object of this arrange~er.t was :
to save on the floor space area required for the hydrocyclones above the equipment floor while the feed, accept and reject collection piping was installed beneath the floor together with the necessary Yalves on each unit for adjusting pressures and for isolating individual "canisters" . This form of system did save space but there were a number of disadvantages in t~at the operation of individual hydrocyclones could not be observed;
thus, if one or more hydrocyclones became plugged during operation, the operator had no way of detec~ing such plugging until the ef~iciency of the entire unit was decreased sufficiently as to call for a shut-down of that unit and disassembly of same thereby to allow the defective hydrocyclones to be removed and replacsd. Furthermore, access to the various valves and pressure gauges for each uni~ was awkward because they were all located under the equipment floor and a special walXway was required under the ~lo~r to enable the operator to have access to such valves and gauges. These systems were also operated with reject pressures above atmospheric and it was requiFed that they be adjusted with accuracy in order to control the operation of the cleaner since the cleaners are very sensitive to the difference in pressure between the accept and reject openings.
2~ More recently, alternative forms of modular hydroc~clyone separator systems have been devised in an effort to overcome the above noted problems with the '~canistern system.
These new systems involve vertically disposed,suitably spaced feed, accept, and re~ect headers. The individual hydrocyclones are connected to these headers and are positioned in generally vertical planes in su~stantially horizontal positions, one above the other. Thus, operator control of the cleaning system is facilitated and the operation of individual hydrocyclones cant be obser~ed. ~owever, while the above noted "canister" systems did permit operation at reduced feea pressures due to ths elimination of some of the pressure losses caused by the feed piping arrang2ments of conventional systems, the above noted .. . - :
modular system emp~oying vertically disposed,separate accept, feed,and reject headers,still suffers from the dïsad~antages inherent in the older systems insofar as pressure losses are concerned. ~he hydrocyclones used with these systems all employ a single tangential feed entry and, in common with the older prior art systems, have a built-in pressure loss at the poi~t where the feed st~c~ turns from the feed header into the indi~idual feed inlet pipes for each hydrocyclone, and also along the length-~ of the feed inlet pipesj an~ als~-on entry into the geparation chambers of the individuai hydroCY~lnes-In aadition, there is a loss of pressure at the points where the accept stock from the hydrocyclones enters the accept header frGm the accept pipes associated with each hydrocyclone. Thus, in order to obtain the cleaning efficiency desired, these later forms of modula~ cleaning systems, in common with the earliest systems, typically require stoc~ feed pressures in the feed header in the order of 4~ pounds per square inch gauge, whereas the above noted canister systems required feed pressures of much lower magnitude since they did not require the complex ~;
2~ fe~d inlet pipes for each indiviaual hydrocyclone as in the o~her systems noted above.
It is a general object ~f the present invention to provide improve~ents in hydrocyclones and in hydrocyclone systems, which incorporate the advantages noted above in connection with the later forms of modular cleaning systems as well as providin~ the low pressure operating characteristics inherent in the "canister" cleaning systems.
Th~ present lnvention thus involves, among other things, improved hydrocyclone separators per se, -particularly improvements in the feed and accept regions of same and improved methods of separating suspensions in such hydro-cyclone separators as claimed in parent application S.N. 270,494.
., . ,~.. _. ..... .... . . . .. . .. .
The present divisional particularly concerns improvements in cleaning systems including a novel form of feed and accept header arrangement for supplying groups of such hydrocyclones.
Thus,the present invention in one aspect provides a cleaning system for liquid suspensions comprising an elongated combination feed and accept header having a plurality of hydrocyclone separators detachably connected thereto and projecting laterally outwardly from said header in spaced apart relation therealong, each said hydrocyclone separator including an elongated separator chamber having a large end and an oppositely disposed small end with a reject outlet therein, the large end of the separator chamber having an annular wall, and a tubular outlet for accept material disposed at said large end in concentric relation to said annular wall, with a sub- ~
stantially full annular inlet for feed suspension into said -.
separator chamber being defined between said annular wall and the tubular accept outlet, and guide vane means being-located in said annuiar inlet between said annular wall and said tubular accept outlet, said guide vane means being adapted to cause the feed suspension flowing through said annular inlet toward the separator chamber to move in a spiral path whereby to set up a fluid vor~ex in the separator chamber; said feed and accept header including an outer wall and a dividing wall therein to separate a flow of feed suspension from a flow of accept suspension in said header; a plurality of tubular accept nipples connected to said .
dividing wall in aligned spaced apart relation for fluid flow there-through and each of said accept nipples being sealingly detachably connected to a respective one of the tubular accept outlets of the hydrocyclone separators; a corresponding plurality of tubular feed nipples each surrounding a respective one of said accept nipples in spaced concentric relation therewith and being connected , 1~44SO
to said outer wall of the feed and accept header for fluid flow theréthrough and each of said tubular feed nipples being sealingly detachably connected to a respective one of the annular wall portions at the large ends of the respective hydrocyclone separators, whereby feed suspension from said header can pass ;
toward the separator chambers of the hydrocyclones through the annular inlets defined between said concentrically arranged feed ;~
and accept nipples while permitting accept suspension to pass from each separator chamber through said connected tubular accept outlets and accept nipples and thence through said dividing wall to join the flow of accept suspension in said header.
In a further aspect the system includes an elongated xejects header disposed in spaced generally parallel relationship to the feed and accept header, and the respective reject outlets of said separators being adapted to discharge to the rejects he'ader.
The individual hydrocyclone separators can be easily r~moved from the header system for repair and/or replacement.
In a preferred form of the invention said annular wall portion of each hydrocyclone separator defines an annular seat thereon which sealingly engages with its associated feed nipple of the header.
In accordance with a further feature of the invention, both said annular seatand said feed nipple have radially outwardly -extending co-operating annular lips thereon, and a clamping means engaging said lips and securing the hydrocyclone chamber to the feed nipple, and the tubular accept nipple being in mating telescoped relation to the associated tubular accept outlet of the hydrocyclone.
In a further feature said outer wall of the feed and accept header comprises a relatively large diameter pipe and said dividing wall comprises a plate separating the interior of the pipe into two regions.
As an additional feature, said outer wall of the feed and accept header comprises a relatively large diameter pipe and said inner wall is in the form of a pipe located within the outer pipe and spaced therefrom in the radial direction to allow for the flow of the feed suspension therebetween.
10In a preferred form of the invention, there are provided support frame members extending between the feed and accept header and the rejects header for stabilizing the latter, the headers, support frame members and the hydrocyclone separators all lying substantially parallel to a common -vertical plane.
In a further feature of the invention both of said headers are arranged in a generally upstanding position with the hydrocyclone separators extending therebetween being slightly inclined from the horizontal so as to permit virtually all suspension to drain from the system after shut-down.
The principles of the invention and the advantages associated therewith will be better understood from the following description of preferred embodiments of same with reference being had to the drawings wherein:
Figure 1 is a view, partly in section, of a hydrocyclone separator in accordance with the invention and connected to a combined feed and accept header arrangement in accordance with a further feature of the invention;
Figure 2 is a longitudinal section view of the .~
10~44S0 inlet feed portion of the hydrocyclone in acc~rdance with the invention and illustrating the manner of connection of same to the combined feed and accept header arrangement;
Figure 3 is an end elevation view of the com~ined accept outlet and guide vane arrangement;
Figure 4 is a view similar to Fig. 3 but showing the opposite end of the combined accept outlet and guide vane arrangement;
Figure 5 is a section view illustrating details of the guide vane arrangement in the helical section ~ -thereof;
Figure 6 is a longitudinal section view of one form of c~mhined feed and acc~pt header arrangement;
Figure 7 is a cross-section ~iew taken along line 7- 7 of Pi~. 6 and looking in the direction of the arrows;
Figure 8 is a longitudinal section view of a fuxt~er for~ of com~ined feed and accept header arrangement;
Figuse 9 is a cross-se¢tion view taXen along line 9-9 of Fig. 8 and looking in the direction of the arrows;
Figure 10 is a side elevation view of a mcdular cleaning system L~ lustrating a series of hydrocyclone separators in accordance with the invention and connected to a combined feed and accept header arrangement and also to a the reject header arrangement;
Figure 11 is a section view taken along line 11-11 of Fig. 10 a~d looking in the direction of the arrows.
With reference now to the drawings there is shown at Figure 1 typical hydrocyclone assemblies 20 connected to a combined feed and accept header 22. The hydrocyclone 20 includes a wa~l 24 defining an elongated chamber of generally circular cross-section. This wall includes a ' ' . . : . ' ': . , ' ' . -. , ' ' ~ ' . ' ~ ' . ,' . ' , ' ~084450 generally cylindrical section 26 defining the large end of the hydrocyclone,which cylindrical wall portion is connected to . ~ -a conical wall portion 28 which tapers generally uniformly down to reject outlet 30 at the apex of the conical.portion, such reject outlet being defined by a tip portion 32. The wall o~ t~e reject outlet passage is preCerably~ but not necessarily, ~:
provided with spiral groove defining means of the type illustrated .
in ~.S. patent 3,800,946 dated April 2, 1974 and assigned to ~ -the assignee of the present in~ention.
L0 An acrept outlet and guide vane arrangement 34 ~s located.withln the large end of the hydrocyclone , i-e-within the cylindrical section 26 thereof. That portion of the elongated chamber within which assembly 34 is located is termed the inlet section of the chamber. That portion of the hydrocylone chamber intermediate the inlet section of the -.
chamber and the apex or tip portion 32 i5 termed the separation :.
chamber. This assembly 34 communicates with an accept nipple .
36 forming part of the feed and accept header 22 while the wall of the hydrocylone 24 is connected at the large end there-of to a feed nipple 38 also forming a part of the above mentioned feed and accept header 22. A more detailed descrip- :
tion of suitable forms of feed and accept headers in accordance with the invention will follow hereinafter. .
The accept outlet and guide vane assembly 34 is adapted to introduce feed suspension generally tangentially into the separation chamber defined by wall 24 thereby to provide a high velocity fluid vortex within such chamber with the heavier portions of the suspension passing downwardly and ~ around the wall of the chamber and ultimately passing out of the reject outlet 30. The lighter fractions of the suspension move toward the axis of the separation chamber and join an oppositely moving helical flow which surrounds an air core 44~0 passing along the hydrocylone axis ~ith such lighter fractions ~;
utlimately paSsing outwardly of the hydrocylQne through the above noted accept conduit 36. ' With reference now to Figures 2-5, àt will be seen that the accept outlet and guide vane assembly 34 i5 disposed in the inlet section of the elongated chamber at the large end of the hydro~yclone separator 20 and ~ithin the cylindrical wall portion 26 thereof. The assembly 34 includes an elongated tubular member 40 having a pair of guide vanes 42 extending outwardly therefrom, with such guide vanes 42 being located in the annular space defined between tubular member 40 and the interior wall 45 of the inlet section of the elongated chamber.
The outermost edges of the guide ~anes 42 contact the inner wall 45 of the inlet section of the chamber thereby to prevent by-pass of fluid therebetween. The assembly 34 is maintained in position within the hydroclone chamber by means of pro-jections 35 formed on the outer extremity of each vane 42, which projections seat in corresponding recesses formed in the wall of the chamber at the large end thereof.
The two guide vanes 42 each include two sections i.e.
a transition section having a length Lt as shown in Fig. 2 for gradually swinging the suspension from a generally longitudinal -direction to a generally spiral direction while gradually accelerating the suspension, and a helical section having a length Lh as shown in Figure 2 arranged to cause the suspension to rotate around the chamber axis in the inlet , section to impart centrifugal forces thereto prior to feeding the suspension into the separation chamber.
With continued reference to Fig. 2 it wil~ be seen that the two guide vanes 42 are disposed at a rela-lively shallow angle e.g. 10 to the axis of the separator at the -inlet end thereof with such angle gradually increasing _ 10-.
10l~44S0 to an angle of about 84 at the end of the transition section. The channels defined by the guide vanes 42 are initially of relati~ely large cross-sectional area.
The guide vanes interfere in only a very minor way with the flow of the fluid. Since the two channels are of relatively lasge cross-section, a relatively low fluid velocity at the entry to the channels is maintained. ~he inlet vane angle of ~ ~ -about lO~ is considered reasonable fcr negligible pressure loss and, in this way, the axial length Lt of the transition section is maintained within reasonable l~mits. Furthermore, in the transition section, because o~ the change in the angles which the guide vanes 42 m~e with the a~;s of the separator, there is a gradual decrease in ~he cross-sectional area of such channels along the length thereof. This gradual reduction in cross-section and the gradual change of angle of the guide vanes 42 results in a transition from what is initially essent-ially axial flow to flow that is essentially in a spiral direct-ion. This transitition in f low direction and the acceleration of the fluid are achieved in a relatively smooth fashion thereby reducing friction and shock pressure losses.
Following the transition section, the suspension smoothly enters the helical section referred to above. In this section the guide vanes 42 are at a constant angle to the axis of the separator and are hence of constant lead in the same sense as used in relation to a screw thread and define flow channels of substantially constant cross-sectional area along the length of same. This cross-sectional area is of course measured at right a~gles to the direction of the flow.
The helical section is of sufficient length as to carry the fluid in each of the channels around the hydrocylone axis by a substantial distance, preferably about one full revolution thus tending to develop a free vortex pattern in the suspension 10~44SO ~-which had been previously accelerated in the transition channels. This rotational motion of the fluid provides for some separation or cleaning of the suspension under the in- -fluence of centrifugal and shearing forces so that on enter-ing the separation chamber larger particles have been pre- ~
ferentially vortexed outwardly toward the wall 45 of the ~ ' chamber thus reducing their potential for "short circuit" ''' flow down the outside and around the end of the vortex ~, finder 44, the latter extending downwardly into the separation ~ -chamber for a desired ~istance beyond the terminal portion of the he7ical section of the guide vanes 42. By reducing the tendency for "short circuit" flow to occur, cleaning efficiency ,,'~
is increased.
With reference to Figure 4, which illustrates the exit portions 46 and 48 of the two channels formed by the guide vanes 42, it will be seen that the stock makes entry into the separation chamber from the inlet section across the full width of the annular space be~ween the tubular vortex finder 44 and the interior wall of the elongated chamber. This full annular entry is advantageous because:
(1) It further reduces the tendency for nshort circuit" ,-flow. (In conventional hydrocyclones wherein the fluid enters tangentially through one or more inlets in the side wall of the hydrocyclone, it has been shown that the stationary roof or top of the co~ventional hydrocyclone creates an obstruction to , tangential flow with this obstruction causing a portion of the feed liquid to pass directly acro'ss the cyclone roof and down the outsi~e wall of the vortex finder to join the accept flow with_n the vortex finder). By providing full annular entry, '' the "stationary roof" effect is substan~ially''eliminated.
12) the full annular entry also reduces shoc~ losses of _ 12 _ .. . . ... .. ...
1~84450 fluid on entering the separation chamber. In conventional hydrocyclones,shoc~ losses occur as the result of the meeting of two flow streams having different velocity distribution.s ,, i.e. the flow stream entering through the tangential inlet ' and the flaw stream provided by the vortexing liquid within , the chamber. With the present arrangement all of the fluid ;, entering the separation chamber is already in rotation and ;: is almost in a fully developed free vortex pattern and, thu~s, '~, since it occupies the entire annular space between the vortex fi~der and the inside wall 45 of the separation chamber there ' will be mini~al flow-disturbance as it attains a fully developed free vortex-forced ~ortex patter~ in the separation chamber.
It will also be noted with reference to .~ Figures 3 and 4 that the opposed guide vanes 42 are not exactly diametrically opposed i.e. they are off-set slightly fr diametral positions by a smzll angular amount which preferably ~ is in the order of 5 or somewhat more. While this slightly ,~ offset arrangement is by no means essential, the slightly off-set rangeme~t shown is belie~ed to possess certain advantages in that the feed pumps which feed the hydrocyclone usually tend ' to set up a small amount of pulsation in the fluid-entering the hydrocyclone. If the channels defined by guide vanes 42 are ' exactly-symmetrically arranged with the discharges 46 and 48 '~ .thereof in diametric symmetry, the resulting pulse at entry to the hydrocyclone will have the amplitudes of thése fluid pulses.
~y arranging for the flow channels to be slightly asymmetric as shown in the drawings, the total pulsations so formed by the existence of these two pulsations will be decreased because they ,will be,out of phase with one another and consequently the .
`~ 30 total amount of vibration of a bank of such hydrocyclones will ;
: _ 13 _ , : ;
11)~44SO -ba reduced somewhat.
With further reference to the accept outlet and guide vane assembly 34, it will be seen that the tubular portion 40 thereof includes a portion 50 extending out~ardly of the large .:~
end of the hydrocylone and providing a means fQr connection to ..
the acc:ept nipple. 36 noted above. As sho~n in ~igure 2, in order to permit the accept nipple 36 to seat within the end ; . -of this tubular portion 50, the latter includes a radially '~ outwardly stepped portion 52 with. an annular groove 54 therein which serves to contain a resilient O-ring gasket thereby preventing leakage of fluids between tubular portion 50 of - -the accept outlet and the accept nipple. 36.
The wall 26 of the elongated chamber terminates at . the large end thereof at an annular rim 60, the annular rim .-defining an annular seat 62 thereon adapted to sealingly engage :
with a similar form of rim on the feed nipple 38. This annular rim 60 includes a radially outwardly extending lip 64 thereby to enable the elongated chamber to be connected to the feed :
nipple. 38 by means of a conventional V-band clamp 66. The . .
2Q wall 26 of the chamber is also radially outwardly stepped at 67 thereby to permit the extreme end of the feed conduit 38 to fit snugly therein.
Typical forms of combination feed and accept headers are shown in Figures 6-9. With reference to Figures 6 and 7 it will be seen that the feed and accept header 22a includes -.:
a cylindrical outer wall 70 having a divider wall 72 disposed therein thereby to provide for separation between the accept region 74 and the feed region 76. A plurality of tubular accept nipples 36a are connected to the dividing wall 72 in aligned spaced apart relation for fluid flaw therethroush w~ h such accept nipples 36a being adapted for connection to the respective end portions 50 of the t.ubular accept outlets of ~L0844SO
a series of hydrocylone separators in the manner illustrated in Fig. 2. A corresponding plurality of tubular feed nipples 38a are provided each surrounding a respective one of the accept nipples 38a in spaced concentric relation therewith, with each feed nipple 38a being connected to the cylindrical outer wall 70 for fluid flow therethrough. The terminal end portions of the feed nipples 38a are provided with annular rim portions 78 adapted to cooperate with the annular rim portions 64 of the hydrocyclone separator described above in connection with Figure 2 thereby to enable the respective separators to be connected thereto by V-band clamps 66 as described above.
The ~eéd ~uspension is supplied to the feed . .
region 76 of the header by way of a feed inlet 80 which is also connected to the wall 72,while the accept suspension exits by way of a tubular outlet 82 connected to cylindrical wall 70.
It will be appreciated that the assem~ly shcwn in Figures 6 and 7 can be made of any desired length thereby to accommodate any desired number of hydrocyclones.
The embodiment shown in Figures 8 and 9 is very much the same in principle as the embodiment of ~igures 6 , and 7 except that the inner dividing wall is in the form of an elongated pipe 72b of circular cross-section with the outer ~;lall 70b being in the form of a relatively large diameter pipe surrounding the inner pipe 72b. Thus, the feed suspension passes along the annular space provided between the outer pipe 70b and inner pipe 72b. The individual tubular ;~ feed nipples 38b are connected in spaced apart relationship to the outer pipe 70b while the individual accept nipples 36b are connected in spaced apart relationship to the inner pipe i 72b. One end of the inner pipe 72b is provided ~ith a flanged connection 84 for connection to a suitable accept header (not ' ~ - 15 -shown) while the outér pipe 70b is pn~nded with a f~nged ~ne ~ on 86 for o~ec ;on to a sul ~ le feed he ~ r (not ~n).
The header assembly illustrated i~ Fig. i and referred to previously is very similar to the one shown in Figs. 6 and 7 except that it makes provision for the connection thereto of two spaced parallel rows of hydro-cyclone separators.
By virtue of the above described arrangements,the feed suspension enters the inlet region of the individual ~ydrocyclones fr~m the feod region of the com~ined feed-accept header with a relatively low pressure loss due to the relatively large size of the inlet. The combined feed-accept header is sized such that the fluid velocities therein are relatively low and, by virtue cf the fact th-t the feed stoc~
enters the hydrocyclone through the relati~ely large annular area between the accept nipple 36a and the feed nipple 3~a, relatively low fluid velocities are maintained thus resulti~g in negligible pressure losses since such pressure losses are proportional to the sguare of the fluid velocity. The friction and shock losses inherent i~ conventional syst~ms are very significantly reduced when using tAe apparat~s as described abo~e, thus enabling the cleaning systems of the in~ention to operate at relatively low feed pressures.
A typical modular pulp stoc~ cleaning syste~
employing a combinea feed-accept header arrangement and hydrocyclones according to the present invention is illustrated in Figures 10 and 11. The header arrangement 22b is of the type illustrated in Figures 8 and 9. It will be seen fr~m Figure 10 that the feed-accept header 22b is located in a generally upright position but is inclined slightly from the vertical e.g. by an angle of about 5. Also provided, in spaced parallel relationship to the header 22b,is a reject header 90.
A plurality of hydrocyclone separators 20 are connected between _ 16 _ - 1~184450 the heade~s 22b and 90 in vertically spaced apart relationship i.e. the separators are disposed one above the other in a generally vertica plane. The longitudinal axes of the hydrocyclone separators 20 are also inclined from the horizontal by about 5 thus allowing suspension to drain therefrom when the equipment i~ shut down.
The individual separators 20 are connected to the--feed-accept he~der-22b-by means-of-V-band-clamps 66 as-described above. The opposing reject end portions-of the separator are connected to the reject header 90 via a transparent si~ht glass 92 a~d a tubular adapter member 94. Thus, the rejact flows from the separators 20 can easily be observed.
~ he above noted assem~ly is provided with a simple support frame 100 includi~g upright legs 102 connecte~
at their upper end to horizontally extending frame members 104, the latter being interconnected between the header 2Zb and the header 90 The upper ends of the aboYe two headers are also interconnected by means of horizor,tally extending frame members lOo. The separators 20 are additionally supported by means of a generally upright frame member 108 extending between frame members 104 and 106, frame member 108 having a series of angularly arranged plates 110 (see Fig. 11) welded thereto in ~paced apart relationship with such plates 110 serving to su~oort therebetween the cyclone separators 20.
The above noted frame 100 is suitably welded together and is provided with the necessary cross-members, bracing members etc., none of which need tc be described here.
The feed-accept header 22b is connected to a pipe 114 which supplies feed stoc~ thereto via a vertically ~isposed pipe 116 extending upwardly through the floor. A
control valve 118 i~ disposed in the feed line in conventional - manner. The accept flow passes outwardl~ of header 22b via -17 ~
844s0 pipe 120 and passes downwardly through a vertical pipe 122 which extends through the equipment floor. A sui~able control valve 124,is also provided in this line in conventio~al fashion. The reject flow frcm header 90 also passes downwardly through a vertically disposed pipe 126~
In practice, two such modular assemblies as sh~wn in Figure 10 are placed close toge~her in side-by-side ralationship. The amount of floor space occupied by such an :. - - .
arrangement is relatively small and the operator has ready 1~- access to the feed and accept control valves 118 and 124 for each~-assembly. On shut-down of the assem~ly, both the feed-accept header 22b and the separators 20 have an opportunity to drai~
cQmpletely thus eliminating problems of stock remaining in the system and subsequently drying up thereby producing lumps of stock which can cause a problem later on at start-up.
The system shown in Figures 10 and 11 is also ~ery easy to ser~ice. The individual hydrocyclone separators 2~ are clamped to the header 22b by means of simple V-~and . .; .
clamps 66 which permit the hydrocyclones to be quickly removed ; 2~ for servicing~ The structure as a whole is relatively simple in construction and employ~ a minimum of piping and connections Y thus making the arrangement less expensive ~or the manufacturer ~ to build.
~.; .
~i ~eturni~g now to the hydrocyclone separator per se, Tables 1 and 2 which follow outline test aata obtained ~ for a typical hydrocyclone in accordance with the present !~.' invention (designated by the ~odel number ELP-440) in comparison with the test data obtained for a conventional hydrocyclone odel EIP-420), the latter having the same overall dimensions .;- .
` 30 as the ELP-440 Model, but being provided with a conventional single tangential inlet provided in the wall of the hydrocyclone adjacent the large end thereof and being connected to a ,~ conventional feed and accept header system.
_ 18 _ ;: .
.:..... .. . . . . .. . . . .. .. ... .
? 1~445() ?
The ETP-440 Model in accordance with the invention had the following dimensions, reference being had to Figs. 1, 2 and 5:
TABIE OF DlMENSIONS (ELP~40) .. . .. ... ..... .... ... . . . . .. .... .... ....
(a) Dimensions of Fee'd and Accept Arran~ement Ll-(guide vane section length)=9.50 in.
Lt=(vane transition sectio~ length)=7.00 in.
~3 (~ane helical section length)=2.50 in.
L2-(accept outlet extension length)= 3.0~ ~n.
L3- (vortex finder length) ~ 3.00 in.
~1- (maximum inside diameter of accept~ = 2.35 in.
D2- (maximum outside diameter of accept) = 3.50 in.
D3- (Spiral feed vane diameter) = 6.00 in.
= (inside top cone diameter(D6) D4- (minimum inside diameter of vortex finder)= 2.00 in.
D5- (minimum outside diameter of vortex finder)=2.50 in.
(b) Guide ~ane Dimensions Tl - (space at ~ane edge(helical sect.)=0.55 in.
T2 - (~ane thickness at outer edge) = 0.30 in.
T3 - (vane lead in helical section) = 1.70 in.
T4 - (~ane radial width(max.)) - 1.63 in.
(decreases to 1.25 in. at point B) T5 - (vane root dLmension(average) = 0.43 in.
(in lower helical section only) - (va~e taper angle)= 2 - (an71e of guide vane to axis of separator at point B)= 10 (this angle increases gradually to about 84 at end of transition section) (c~ Overall Dimensions of Separator ~ .
L4 -(length of cylindrical section) = 25 ins.
~ - 51ength of conical section includins tip)=34 ins.
~ g , .. . .. .
i~l844SO
. . . .
C~ - (cone included angle) = 9 D7 - (inside diameter of reject outlet tip) = 5/8 in.
~this may ~ary depending on circumstances) The test results are gi~en in the following -Tables 1, 2 and 3. :.
.... . . . .. ... . .. .. . ..
~EST RESULTS - PROTOTYP~ ELP-440 ... ...
.. ...... Efflciency 440 vs 420 Tert'y Bleachèd Softwood Kraft Pulp ~ eed Tempe~ at~re 55C .
Cleaner Test!Pressures (psig) Feed Stock % Dirt Counts Model Codel _ DP Capacity Cons'y Reject SPecks/GM
No. !Feed Acc F~A USGPM-- %OD Feed Rate Feed Reject 440 1 135 10 25 liO .316 29. 9 13 48 440 2 130 10 20 126 . 305 30.6 10 56 440 3 !2s lo 1S 106 .310 32.3 10 43 420 8 40 6 34 120 .300 28.0 9 31 420 9 35 5 1/2 29 1~2 114.319 21. 6 N.M. N.M.
420 10 40 10 30 113 .313 60.g 10 Z3 . Efficiency 440 vs 420 Primary Unbleached Ammonia-Based Sulphite Pulp Temp = 21C.
ELP-440 and ELP-420 Tested Simultaneously Compare Tests l~l,lA&lA,e r !Cleaner Test Pres~ 'ures ~psig) Feed Stock % Dirt Removal Model. Code . DP Capacity Cons ' y ~ej ect Ef ficiency , No. Feed Acc F/A USGPM %OD Feed R2te -DF-DA x 100 _ 440: 1 24 10 14112.5 0.575 11.8 65 : 440 2 26 12 14113.5 0.423 15.7 . 60 ...
420 1 34 6.5 27.5100.9 0.575 14.4 65 420 2 34 - 6.5 27.5101.8 0.423 15.3 58 = _ 440 lA 24 10 14113.0 .578 10.9 56 440 2A 20 10 1096.4 .597 13.4 43 .
420 lA 34 6.5 27.510~.4 .578 6.8 44 420 2A 34 B.5 25.596.9 597 16.8 52 .
.
_ 20 _ . ~, , . , , . ~ . .
.
. Performance ELP 440 Secondary Bleach~ ~d ~ardwooF L Rraft Pulp Temperature.=llZ~ F~;.
Pressures (psig) Feed Feed %. . Dirt Coun~s %Eff'y=
Feed Acc D~ Capacity Cons'y Reject (7 ~and (sP/gm) DF-DA
F/A USG~M ~OD Rate Sheets. 1.5 qmea. DF x~n F~eFd ADAept "
. . . ~
24 . 10 .14 111.6 0.68 17.8 12.89 4.11 68 22 8 14 112.5 0.71 13.5 12.56 2.46 80 6 14 111.9 0.72 10.6 1 ~ 2.81 76 It will be noted from Tables 1 and 2 that the feed to accept differential pressure required for the EIR-440 in accordance with the invention was only about 1/2 of the differential required for the EL2-420. At the same tIme the ELP-440 achieved similar feed capacities a~d similar dirt re~oval efficiencies as compared with the ELP-420. Thus, the very significant reduction in differential pressure required by ~he a~ove cleaner represents a very significant saving in .; the overall energy used for the cleaning of pulp stock. Similar -'` savings in energy are anticipated in connection with the separl~tiDg o~ otDer types of susp-nsioDs~ :
: 30 , :
, .. . . .
Claims (8)
1. A cleaning system for liquid suspensions comprising an elongated combination feed and accept header having a plurality of hydrocyclone separators detachably connected thereto and projecting laterally outwardly from said header in spaced apart relation therealong, each said hydrocyclone separator including an elongated separator chamber having a large end and an oppositely disposed small end with a reject outlet therein, the large end of the separator chamber having an annular wall, and a tubular outlet for accept material disposed at said large end in concentric relation to said annularwall, with a sub-stantially full annular inlet for feed suspension into said separator chamber being defined between said annular wall and the tubular accept outlet, and guide vane means being located in said annular inlet between said annular wall and said tubular accept outlet, said guide vane means being adapted to cause the feed suspension flowing through said annular inlet toward the separator chamber to move in a spiral path whereby to set up a fluid vortex in the separator chamber; said feed and accept header including an outer wall and a dividing wall therein to separate a flow of feed suspension from a flow of accept suspension in said header; a plurality of tubular accept nipples connected to said dividing wall in aligned spaced apart relation for fluid flow there-through and each of said accept nipples being sealingly detachably connected to a respective one of the tubular accept outlets of the hydrocyclone separators; a corresponding plurality of tubular feed nipples each surrounding a respective one of said accept nipples in spaced concentric relation therewith and being connected to said outer wall of the feed and accept header for fluid flow therethrough and each of said tubular feed nipples being sealingly detachably connected to a respective one of the annular wall portions at the large ends of the respective hydrocyclone separators, whereby feed suspension from said header can pass toward the separator chambers of the hydrocyclones through the annular inlets defined between said concentrically arranged feed and accept nipples while permitting accept suspension to pass from each separator chamber through said connected tubular accept outlets and accept nipples and thence through said dividing wall to join the flow of accept suspension in said header.
2. The cleaning system according to claim 1 including an elongated rejects header disposed in spaced generally parallel relationship to the feed and accept header, and the respective reject outlets of said separators being adapted to discharge into the rejects header.
3. The cleaning system according to claim 1 wherein said annular wall portion of each hydrocyclone separator defines an annular seat thereon which is adapted to sealingly engage with its associated feed nipple of the header.
4. The cleaning system according to claim 3 wherein both said annular seat and said feed nipple have radially outwardly extending co-operating annular lips thereon, and a clamping means engaging said lips and securing the hydrocyclone chamber to the feed nipple, and the tubular accept nipple being in mating telescoped relation to the associated tubular accept outlet of the hydrocyclone.
5. The cleaning system according to any one of claims 1, 2 or 3 wherein said outer wall of the feed and accept header comprises a relatively large diameter pipe and said dividing wall comprises a plate separating the interior of the pipe into two regions.
6. The cleaning system according to any one of claims 1, 2 or 3 wherein said outer wall of the feed and accept header comprises a relatively large diameter pipe and said inner wall is in the form of a pipe located within the outer pipe and spaced therefrom in the radial direction to allow for the flow of the feed suspension therebetween.
7. The cleaning system according to claim 2 wherein there are provided support frame members extending between the feed and accept header and the rejects header for stabilizing the latter; the headers, support frame members and the hydrocyclone separators all lying substantially parallel to a common vertical plane.
8. The cleaning system according to claim 2 or claim 7 wherein both of said headers are arranged in a generally upstanding position with the hydrocyclone separators extending therebetween being slightly inclined from the horizontal so as to permit virtually all suspension to drain from the system after shut-down.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA326,851A CA1084450A (en) | 1977-01-26 | 1979-05-03 | Hydrocyclone system including improved header- manifold arrangements |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA270,494A CA1063974A (en) | 1977-01-26 | 1977-01-26 | Hydrocyclone system including axial feed and tangential transition sections |
| CA326,851A CA1084450A (en) | 1977-01-26 | 1979-05-03 | Hydrocyclone system including improved header- manifold arrangements |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1084450A true CA1084450A (en) | 1980-08-26 |
Family
ID=25668441
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA326,851A Expired CA1084450A (en) | 1977-01-26 | 1979-05-03 | Hydrocyclone system including improved header- manifold arrangements |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1084450A (en) |
-
1979
- 1979-05-03 CA CA326,851A patent/CA1084450A/en not_active Expired
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| MKEX | Expiry |