US2377721A - Separator of the vortex type for paper pulp - Google Patents

Description

June 5, 1945. H. E. B. scoTT 2,377,721

SEPARATORS OF THE VORTEX TYPE FOR PAPER EULP Filed June 30, 1942 5 Sheets-Sheet l June 5,194'5. H. E. B. SCOTT 2,377,721

SEPARATORS OF THE VORTEX TYPE FOR PAPER PULP 5 Sheets-Sheet 2 Filed June 50, `194:22

June 5, 1945. H. E. B. scoTT sEPAEAToRs oF TEE VORTEX TYPE PQE PAPER PULP Filed June 50, 1942 5 Sheets-Sheet P June 5, 1945. l H. E. B. SCOTT 2,377,721

` SEPARATORS OF THE VORTEX'TYPE FOR PAPER PULP Filed June so, 1942 5 sheets-sheet 4l 'jre/ww /f /ZWMMJW f d. d

June 5, 1945. 7 H, E.- B. SCOTT' 2,377,721

SEPARATORS OF THE VORTEX TYPE FOR PAPER PULP Filed June so, 1942 'sheets-sheet 5 described which has means which the vortex is Patented June 5, 1945 SEPARATOR 01g Harold Eric land, 'assigner THE von'rEx TYPE Fon Aren PULP Baliol Scott, London S. E; 1, Engto Vickerys Limited, London,

England, a company 'of Great Britain and Northern Ireland Application June 30, 1942, Serial No. 449,101 In Great Britain July 15, 1941 20 Claims.

This invention relates to separators for treating liquids and suspensions of solids in liquids, and more particularly for treating paper pulp, in which the material to be treated is injected tangentially at high speed through an inlet tapering to a reduced and substantially rectangular crosssection into a vortex vessel of circular section from which the puried material emerges in an upward direction while the separated impurities are allowed or into a space sheltered from the swirl of the vortex chamber. Separators of this kind have been described in my application Serial No. 346,781.

Though capable of working satisfactorily over a wide range of conditions such separators work best at a particular speed of injection, that is to say at a particular angular velocity of the material to be treated. In practical conditions, however, the through-now must often vary; the volume of pulp supplied to a paper machine will be changed with every change in the type of paper being made and in the consistency at which the pulp is being Worked; also the pulp may be passing through a battery of two or more separators and one may have to be taken" out of service through accidental clogging up or for some other reason, whereupon the through-now of the remaining separators must substantially increase.

A primary purpose of this invention is to enable the separator to work at high efficiency over a wide range of through-flow by maintaining the speed of injection substantially constant notwithstanding variations in the through-flow. A sub.. sidiary purpose is to enable manufacturers to vsatisfy by a small range' of separators demands for separators for different through-flows extending overa wide range.

With these purposes in View one object of the invention is a vortex separator of the type above for constricting the inlet channel either in the inlet nozzle by which the material treated is injected or in the circular duct which continues the inlet nozzle and in formed. It is important that such means shall not disturb the formation of the vortex, as would occur if its outer layers should be'directed inward across the vortex ow; the outer wall of the nozzle should therefore be con- 'tinuous with the outer wall of the vortex-formingv duct and constriction should be effected by modiiicationV of another wall bounding the inlet channel.

Wholly to achieve the aim of constant angular velocity involves increasing the head of supply as the flow diminishes, and therefore pulp should encouraged to settle, preferablybe delivered to the separator by a pump having a slightly drooping pressure-output characteristic such as is readily obtained by suitable design in a centrifugal pump. A rise of from 5 to 6% in the pressure has been found sufficient to cover a range of output from full load to 2/5 `iull load.

For the purpose of adapting a given design of separator to any xed through-flow within a small range the necessary constriction of the inlet channel may be effected once for all at the factory. To suit a separator to the varying through-now occurring in the paper factory the means for constricting the inlet channel must be under the control of the user. A further object of the invention is a separator in which; the area of cross-section of -the inlet channel at its smallest is controlled automatically in accordance with the through-dow. More specifically, an. object of the invention is a vortex separator with means for constricting its inlet channel governed by a float adjacent to a Weir in one of the conduits by which the material treated is led to and from the separator.

For very Wide variations of the through-flow it may be desirable to vary the area. of the outlet also in the same sense as the through-flow. Varying the area of outlet as the inlet flow area is varied in accordance with Variations of through liow, tends to control pressure within the vessel which influences the effective length of the vortex. Yet another object of the invention, therefore, is a separator having interconnected means of varying the cross-sectional area of both the inlet channel and the outlet conduit.

Further objects of the invention will appear from the detailed description following.

A number of possible constructions of variable inlet for the purpose of the invention are illustrated in the accompanying drawings;

Figures 1 and 2 are elevation and plan respectively, each partly in section, of the head of a vortex separator having both a variable inlet and a variable outlet;

Figure 3 is an elevation in section on the line 3-3 of Figure 4, and Figure 4 a plan in section on the line 4 4 of Figure 3 of a modified construcion;

Figure 5 is an elevation of the movable part of the variable inlet of Figures 3 and 4;

Figure 6 lis an axial section and Figure 7 a. plan in section on the line 1-1 of Figure 6 of an alternative construction of variable outlet, while Figure 8 is similar to Figure 'l but shows the parts in a different relative position, and Figure 9 is an ele- Vation in section on the line 9-9 of Figure 8.

.tance to ensure this purpose a rounded member I9 'secured to the turned either way Figure 10 is a sectional plan of a third form of variable inlet, in which, as in the constructions so i'ar mentioned, the constriction ail'ects the radial depth of the inlet:

Figure 11 is a plan from underneath, in section on the line II-II of Fig-ure 12, and Figure 12 is an elevation in section on the line I 2-I2 of Figure 11, (the tangential inlet however being shewn in axial section.) oi' a, fourth form of variable inlet. l

Figure 13 is an elevation partly in section of a fifth form of variable inlet which, like the fourth, is variable in effective axial depth.

Figure 14 is a diagram illustrating the auto- Amatic control of a variable inlet, or inlet and outlet.

In all the constructions I is the upper part of the main portion of the vortex vessel proper, and 2 a head bolted on Ito it of which the tapered tangential 'inlet nozzle 3 is a part and within which is the helical path through which the suspension reaches the vortex vessel; an outlet pipe 4 is bolted to the upper ange of the head 2. In Figures l'and 2 the outlet pipe 4 projects downward into the vortex vessel a suiicient disthe desired separation of impurities taking place before the suspension is permitted to turn in an upward direction. Between the ange ofthe outlet pipe and that of the head there is located and secured the ilange of a sleeve 5. a fluid-tight Joint being made between the flanges by suitable packing in annular grooves 3. This sleeve forms a portion of the outlet and fits and iills the cylindrical and concentric portions of the upper part of the vessel formed in the head 2 yabove a circumferential groove in the sleeve. This groove is of increasing radial depth and of the same axial depth as the tangential inlet nozzle 3; this is annular at its'top and thereafter helical. The groove. deepens to the full radial thickness ofthe sleeve, which therefore ends in a helical tail 'I wrapped around the outlet pipe. 'An arm 8 projecting from the sleeve B has bolted to it a toothed segment 9 with which meshes a lpinion II on a vertical shaft I2 supported at its upper end in a bracket I3 secured by the bolts which fasten the head 2 to the vortex vessel I. At aconvenient height lower down the shaft I2 may carry a hand-wheel I4 as appears from Fig. 14, or as hereinafter described with reference tothat figure it may be equipped with automatic operating means.

Figures 1 and 2 also show a means for adjusting the effective cross-sectional area of the outlet pipe 4 in correspondence with .and simultaneously with the adjustment of the inlet. For plunger I6 is mounted to slide in a gland I8 in the wall of the outlet pipe 4. There is attached -to it a pin carrying a roller I1 located in a cam slot I8 in a cam arm 8. By turning the shaft I2 by the aid of the handwheel I4 or otherwise the sleeve B may be from the mid position shown Ii' it is turned anti-clockwise as until the point 2| on the sleeve registers with the point 22 on the head 2, the inlet will have its maximum cross-section. In the position shown the inlet is substantially contracted. without sudden change of cross-section and without disturbance oi' the outer layers of the suspension. 'Ihe constriction is at all times close to the beginning of the circular path, so

in the figures. seen in Fig. 2

that the increased speed imparted by the conf striction is eiective in the formation of the vor- There is asimilar bar 80 sleeve 34 '24; above this constriction a. rod

tex. The tail piece I is deepened wherenecessary to prevent any part of the inlet port of the head being uncovered clear of the sleeve 6 in the end position of the latter. The turning of the sleeve also causes the cam I9 to advance the plunger I 5 into or withdraw it from the outlet pipe 4 as the cross-section of the inlet is diminished or increased.

If it is not intended that the user shall have the facility of adjusting the separator to a varying through-flow the arm 8, and adjusting mechanism 3, II, I2, I3, I4 are not required; nor is the packing between 2, 4 and 5. The4 sleeve 5 is set on'ce and for all by the manufacturer to correct for any tolerance in manufacture affecting the through-flow, or to adjust the through-flow to a particular value within a limited, range, and is then xed in position and the parts bolted up tight.

In the modification shown in Figs. 3, 4 and 5 the outlet pipe proper 4 ends at its flange and is prolonged by the inlet-regulating sleeve 23'; the upper part of the sleeve is. as before, of a diameter equal to that of the head and in this part is formed a helical groove as already described. The bore of of the outlet pipe at the sleeve, equa-l to that the top. is constricted at 25 with an enlarged and tapered end 26 is mounted to slide in a gland 2l in the outlet pipe by a bell-'crank lever 28 pivoted on a bracket 29 on the outlet pipe and rocked by the action of the cam I9 upon a roller 3I on its end.

The form of the sleeve 23 is further illustrated ered by the sleeve.

Figures 6 to 9 show an alternative means of varying the cross section of the outlet. In the end of the outlet pipe 4 there is a cross-bar 32 of stream-lined cross-section and spindle shaped. 33 in the sleeve 34 with and in contact with the shown in Fig. 6 the one other and the two oler When the is turned the two bars take .up such a relative position as is shown in 'Figs'. 8 and 9, in which the free area of bore of the outlet pipe is reduced substantially to the minimum. By suitable design of the bars 32 and 33, which may its flatside uppermost bar 32. In the position bar exactly covers the the least obstruction to the flow.

have other forms than that shown, the variation vforked outer end of the bar serves as a means as shown in full a continuation of or, as shown in less into the inlet of adjusting it so that either, lines, its surface is practically the fixed surface of the inlet, dotted lines. it projects more or constricting it radially. In either position its surface makes an angle of not much less than degrees with the adjacent fixed parts of the channel, so that there are no recesses in which the 4: it is moved ifa's'may be necessary original level.

solid matter o! the suspension treated can accumulate lsheltered from It is also possible to restrict the inlet channel by lessening its `axial depth. A construction so operating is shown in Figs. 11 and 12. Between the adjacent ilanges of the vortex vessel I and the head 2 there is `mounted a iiatplate 88, located by annular ribs engaging in grooves in the nantes and turned by an arm 88 in the same manner as the sleeveof Figs. 1 and 2. The head I ls here shown as integral with the outlet pipe 4, and its helical channel is seen in Figure 12 to be more or less obstructed by plate 88 according the sweep of the stream.l

as the plate is turned in one direction orthe y other.

The same effect is obtained in the construction shown in Fig. 13 by making one wall of the helicai channel in the head from va resilient helical strip 4I. Its upper end is while its lower end is recessed and rests upon a pin 42 projecting from the outlet pipe 43, which is made to slide vertically in the head 2. A rack 44 upon the pipe and a pinion 45 engaging it serve for adjusting the inlet, the pinion being turned by hand -or automatically like the shaft I2 of Figs. l and 14. Chain dotted lines indicate the eect of the inlet of raising the outlet pipe.

As a rule it will be sufcient to adjust the inlet by hand. If any guidance is needed as to the proper adiustment it may be given by an indicator operated by a float resting on the stream of suspension treated adjacent to a weir over which it flows in its passage to orfrom the separator. This is diagrammatically illustrated in Illg.I `14.l The mixing boxis shown at 45 with pipes 41 and 48 conveying to it backwater and stock secured to the head,

`pulp withdrawn from 'ai-ator,

When-an auxiliary or secondary separator is used for giving further treatment to the impure the primary separators, as described in my above mentioned specification, the variable inlet oi the auxiliary separator may be used to control the amount of pulp with-- drawn. g

I claim: y

1. A vortex separator comprising a vortex vessel oi circular cross-section, an outlet conduit extending upward out of said vessel from a. vpoint intermediate in its length and with the upper part of the wall of the vortex vessel bounding an annularvortex-forming` duct, an inlet nozzle tapering to a reduced and substantially rectangular cross sectlonjoining said annular duct tangentially near its top and forming therewith an inlet channel, the outer wall of said nozzle being continuous on its inner surface with the outer surface of said duct, and means constituting part of another wall of said inlet channel movable to constrict said inlet channel while maintaining a gradualcurvature of said inner wall in all positionsoi' adjustment and without disturbing ythe forming of the vortex.

2. Apparatus for purifying paper pulpincluding a vortex separator as in claim l having movvable wall means for varying the size of the incoming stream of flow, means responsive to variations in the rate of flow of pulp through said sepand means controlled by said responsive means to actuate said varying size means.

3. Apparatus for purifying paper pulp includ- `ing a vortex separator as in claim 1 having respectively. A pump 49 draws pulp from the mixing box 4t and delivers it to one or more vortex vessels I. The pump should preferably'fhave a slightly drooping pressure-outputcharacteristic, for to obtain constant angular velocity in the vortex vessel involves increasing the head of supply delivered by the separator I into the flow box 5I is maintained in excess of the -dernands f the paper-making machines which the separators serve, and the surplus returns to the mixing box over a'weir 52. Adjacent to this Weir a float 53, which may be in the form of a wheel or roller and may be rotated by a motor 54, rests on the surface of the stream. It is shown as carried -on a radial arm 55 to which is attached a pointer 58 moving over a scale.

If it is desired to make the adjustment of the inlet automatic the same float may govern the action `oi a servo motor for that purpose. i As the motor 54 through an eccentric rocks 1.a pivoted arm 51 carrying two pawls 58, 59, either A- rorboth of which within-toothed wheel 6I f linked to the float 53. As soon as a fall or rise may be held out of engagement by a rocking cam 62 with the or engagement when the limit of adjustment been reached. l t

f'zWhere several vortex separators are `operating of adjustment may be coupled so that the load is at all 'times equally amonsthem.

as the ilow diminishes. The purified pulp I movable wall means for varyingthe size of the incoming stream of flow, means responsive to variations in the rate of vilow of pulp through said separator, a servo-motor, and means con-` trolled byv said responsive means to render said servo-motnr effective to actuate said vvarying means in a direction to decrease the departure of such response from a predetermined value.

4. A vortex separator comprising a vortex vessel of circular cross-section, an outlet conduit extending upward out of said vessel from a point intermediate in its length and with the upper part of the wall of the vortex vessel bounding an annularvortex-forming duct. an inlet nozzle tapering to a reduced and substantially rectangular cross section joining saidannular duct Ytangentially near its top and forming therewith an inlet l channel, the outer wall of said nozzle being continuous on its hinner surface with the outer surface of said duct and means constituting part of i the inner wall o! said inlet channel movable to reduce the radial depth of said channel while maintaining a gradual curvature of said wall.

5. A vortex separator comprising a vortex vessel of circular cross-section, extending upward out of said vessel from a point intermediate in. its length and with the upper part of the cylindrical and concentric wall of the vortex vessel bounding an annular vortex-forming duct, said conduit fitting and lling a cylindrical ,and Iconcentric portion of the upper part of said vortexvessel andhaving in itsouter surface a groove of increasing radial depth which with the wall of the vortex vessel constitutes the vortex-forming duct, an inlet nozzle tapering to a reduced and substantially .rectangular cross section joining said vortex-forming duc-t tangentially and*l forming 'therewith an inlet channel, and means for turning said conduit .tovary the minimum radial deptli'of the inlet channel.

6. A vortex separator comprising -a .vortex vesan outlet conduit Avarying means in a sel of circular cross-section. an outlet conduit extending upward out of said vessel from a point intermediate its length and with the upper part of the wall of the vortex vessel bounding an annular space, an inlet nozzle tapering to a reduced and substantially rectangular cross-section joining said annular space tangentially near its top and forming therewith an inlet channel, the outer wall of said nozzle being continuous on its inner surface with the outer surface of said space, and a sleeve rotatable upon said outlet conduit within the vortex vessel, the outer surface of said sleeve being in part of diminishing radius, diminishing in acircumferential direction, whereby rotation of said sleeve varies the minimum radial depth of the vortex-forming duct formed between said sleeve and the Wall of the vortex vessel.

7. A vortex separator comprising a vortex vessel of circular cross-section, an outlet conduit extending upward out of said vessel from a point intermediate-in its length and with the upper part of the wall of the vortex vessel bounding an annular vortex-forming duct, an inlet nozzle tapering to a reduced and substantially rectangular cross-section joining said annular duct tangentially near its top and forming therewith an inlet channel, the outer wall of said nozzle being continuous on its inner surface with the outer surface of said duct, means constituting part of another wall of said inlet channel movable to constrict said inlet channel without disturbing the forming of the vortex and means mechanically connected with said movable part of the inlet channel wall for correspondingly constricting said outlet conduit.

8. Apparatus for purifying paper pulp including a vortex separator as in claim 7 having movable wall means for varying the size of the incoming and outgoing streams of flow, means responsive to variations in the rate of flow of pulp through said separator, and means controlled by said responsive means to actuate said varying size means.

9. Apparatus for purifying paper pulp including a vortex separator as in claim 7 having movable wall means for varying the size of the incoming and outgoing streams of flow, means responsive to variations in the rate of flow of pulp through said separator, a servo-motor, and means controlled by said responsive means to render said servo-motor effective to actuate said direction to decrease the departure of such response from a predetermined value.

l0. A vortex separator comprising a vortex vessel of circular cross-section, an outlet conduit extending upward to the top of, out of said vessel from a point intermediate ln its length and with the upper part of the cylindrical and concentric wall of the vortex vessel bounding an Vannular vortex-forming duct, said conduit tting and lling a, cylindrical and concentric portion of the upper part of said vortex vessel and having in its outer surface a groove of increasing radial depth which with the wall of the vortex vessel constitutes the vortex-forming duct, a transverse ob-.

struction at the upper end of said conduit, an outlet pipe secured upon asid vortex vessel and continuing said outlet conduit, a. transverse obstruction at the end of said pipe adjacent to the outlet conduit, an inlet nozzle tapering to a reduced and substantially rectangular cross section joining said vortex-forming duct tangentially and forming therewith an inlet channel, and means extending upward out of said vessel from a point` for rotating said conduit to vary the minimum radial depth of the inlet'channel, and to causel said obstructions to overlap to a greater or less extent.

11. A vortex separator comprising a vortex vessel of circular cross-section, an outlet conduit extending upward out of said vessel from a point intermediate in its length and with the upper part of the wall of the vortex vessel bounding an annular space, an inlet nozzle tapering to -a reduced and substantially rectangular cross section joining said annular space ltangentially near its top and forming therewith an inlet channel, the outer wall of said nozzle being continuous on its inner surface with the outer surface of said space, a sleeve rotatable upon said outlet conduit within the vortex vessel, the outer surface of said sleeve being in part of diminishing radius, diminishing in a circumferential direction, whereby rotation of said sleeve varies the minimum radial depth of the vortex-forming duct formed between said sleeve and the wall of the vortex- Vessel an obstruction reciprocable across said outlet conduit to vary its area of cross-section, and a cam rotatable with said sleeve and acting on said obstruction to reciprocate it.

l2. A vortex separator comprising a vortex vessel of circular cross-section, an outlet conduit extending upward out of said vessel from a point intermediate in its length and with the upper part of the wall of the vortex vessel bounding an annular vortex-forming duct, an inlet nozzle tapering toa reduced and substantially rectangu: lar cross-section joining said annular duct tangentially near its top and forming therewith an inlet channel, the outer wall of said nozzle being continuous on its inner surface with the outer surface of said duct, and means for varying the axial depth of said inlet channel.

13. A vortex separator comprising a vortex vessel of circular cross-section, an outlet conduit intermediate in its length and with the upper part of the wall of the vortex vessel bounding an annular vortex-forming duct, an inlet nozzle tapering to a, reduced and substantially rectangular cross section and having a helical end merging into said annular duct tangentially near its top and forming therewith an inlet channel, the outer wall of said nozzle being continuous on its inner surface with the outer surface of said duct, a plate prolonging the bottom of said helical end 0f the inlet nozzle at an angle to its top, and means for shifting said plate in its own plane to vay the effective cross-section of said inlet channe 14. A vortex separator `comprising a vortex vessel of circular cross-section, an outlet conduit extending upward out of ,said vessel from a point intermediate in its length and with the upper part of the cylindrical and concentric wall of the vortex vessel bounding an annular vortex-forming du'ct, an inlet nozzle tapering to a reduced and substantially rectangular cross-section and having a helical end merging into said annular duct tangentially near its top and forming therewith an inlet channel, the outer wall of said nozzle being continuous on its inner surface with the outer surface of said duct, and the bottom wall of said nozzle continuing as a resilient helix forming a partition across said vortex-forming duct, means engaging the end of said helix with said outlet conduit, and means for shifting said 'outlet conduit axially to alter the pitch of said -constrict said inlet extending upward out of intermediate in its length and with the upper helix and the axial depth or the vortex-forming duct. l

15. Apparatus for purifying paper pulp including a vortex separator, conduits conveying pulp to and from said separator, said separator comprising a vortex vessel of circular cross-section, an outlet 4conduit extending upward out ci said vessel from a point intermediate in its length and with the upper part of the wall of the vortex vessel bounding an annular vortex-forming duct. an inlet nozzle tapering to a reduced and substantially rectangular cross section joining said annular duct tangentially near its top and being continuous on its inner surface with the outer surface of said duct, means constituting part of another wall of said inlet channel movable to channel without disturbing the forming of the vortex, a weir in one of the conduits conveying pulp to and from said separator, a float. resting on the surface of the pulp adiacent said weir, and means governed by said float for shifting the movable part of the wall of said inlet whereby the area of inlet is adjusted to the through-now with which the separator has to deal.

16. A vortex separator comprising a vortex vessel of circular cross-section, an outlet conduit said vessel from a point part of the cylindrical and concentrici wall o! the vortex vessel bounding an annular vortexforming duct, said conduit fitting and filling a cylindrical and concentric portion of the upper part o! said vortex vessel and having in its outer surface a groove of increasing radial depth which with the wall ot the vortex vessel constitutes the vortex-forming duct, and an inlet nozzle tapering to a reduced and substantially rectangular cross section Joining said vortex-forming duct tangentially and to ing therewith an inlet channel.

11. A vortex separator comprising a vortex vessel o! circular cross-section, anoutlet conduit extending upward out of said vessel from a point intermediate in its length and with the upper part of the wall of the vortex vessel bounding an annular space, an inlet nozzle tapering to a reduced and substantially rectangular cross-sec- `tion joining said annular space tangentially nearr its top and forming therewith an inlet channel, the outer wall of said nozzle being continuous on its inner surface with the outer surface of said space, and a sleeve upon said outlet cond 't within the vortex vessel, the outer surface of said sleeve being in part of diminishing radius, diminishing in a circumferential direction to de-l limit the inlet channel within said annular space.

18. Apparatus for purifying paper pulp, said apparatus including a vortex vessel of circular cross section, an inlet portion for said vessel having means for varying the cross sectional size of the stream'of pulp entering said vessel, means responsive to the rate of ilow through said vessel, and means controlled by said responsive means to actuate said varying size means to vary the size of the stream with varying rate of flow.

through the vessel to tend to maintain the velocity of flow of said stream in to said vessel at a A desired value.

19. Apparatus for apparatus including a vortex vessel of circular cross section, an inlet portion for said vessel having means for varying the cross sectional size of the stream entering said vessel, an outlet conduit for said vessel having means for varying the size of the outlet stream from said vessel, means re,- sponsive to the rate of ilow through said separator, and means controlled by said responsive means to adjust both of said stream size adjusting means in accordance with varying rates of ilow to tend to maintain the velocity of flow of said stream into said vortex vessel and the pressure within said vessel at desired values.

20. Apparatus including a vortex vessel of cii-,l

cular cross section, an inlet portion for said vessel having means forvarying the cross sectional size of the stream of pulp entering said vessel, said vessel having an outlet, a tank provided with a Weir and arranged in the ilow of pulp which includes said vvortex vessel, a iloat in said tank,

and means responsive to changes of level of said iloat to control said varying means in a direction to tend to maintain the level of said iloat constant.

HAROLD ERIC BALIOL SCOTT.

purifying paper pulp, saidV

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