AU597145B2 - Cyclone separator - Google Patents

Description

CO0M MON W EA L TH OF A UST RA LI A PATENTS ACT 1952 COMPLETE SPECIFICATION (Original) FOR OFFICE USE Class Int. Class Application Number: Lodged: dci Comnplete Specification Lodged: alIld-e. tcnli s the Pririy:Published: Pfliftltrg Ind is Corpel Lflcor Related Art: Nam ofAppicat:SECTION 3460)(a) DIRECTION SEEFO. NAMvE DIRECTED COnqco o~2.1 r1= AL Th 3 'Address of Applicant, £STRATHALBY-NI The-~Crescen-t-, .SASSAFRASr 787- In -the- Sta-te- of V-ictoria-f -Commonweal1thv of.

Australia-- Actual Inventor(s): NOEL CARROLL Address for Service: DAVIES COLLISON, Patent Attorneys, I Little Collins Street, Melbourne, 3000.

Complete specification for the invention entitled: "CYCLONE SEPARATOR" The following statement is a full description of this invention, including the best method of performing it known, to me 1- 2 separat:or havinp a separating chamber having first, second and third ~~~~~~~~~cylindrical portion being ofgetrdimtrtantescn lesser diameter than the second cylindriccl portiotn, the first cylindrical portion having an overflow outtet at the end thereof opposite to said second cylindrical portion and a plurality of tangentially direc ted feed inlets, the separator being adapted to separate liquids onefrom the other in a mixture when infed into said separating chamber via said feed inlets, one said l'.quid emerging from said overflow outlet and the other emerging from sr.

underflow outlet at the end of said third cylindrical portion remote from said first cyl~ndric'al portion4 The above separator is intonded specifically, but not exclusively. for separating oil from water, the oil tn uxte emerging I ti from the overflow outlet and the water from saii third cylindrical portion.

The aforementioned cylindrical portions mayi not be truly cylindrijzalo in the sense that they do not need in all cases to present a side surf-ace which Is -linear in cross-section and para3llel to th~e axis thereof. For example. United State* Patent 4237006 describes arrangements wherein the first cylindrical portion has a frustoconical section adjacent the second cylindrical portion, and which provides a taper between the largest diameter of the first cylindrical portion and the diareter of the second cylindrical portion where ths meets the first cylindriral portion. Likewise, the aforevnentioned patent specification describes arrangements wherein a similar section of frugtoconical form is provided to cause a tapering in the diameter of the second cylindrical portion fromt a largest diameter of the second cylindrical portioi to the diameter of the third cylindrical portion. There is clso described an arrangement wherein the second cvllndrical portion exhibits a 'il~ t.6 .3 constant taper over its whole length.

A difficulty has been found in operating cyclone separators of the kind described in United States Patent 4,237,006 in that proper and reliable separating action is not always achieved, and contamination of the heavier liquid component (that emerging from the aforementioned third cylindrical portion of the separator) with the lighter liquid component sometimes occurs. Another difficulty has been that the outlet for the lighter component will frequently become blocked by debris, thus interfering with operation of the separator.

This invention is based on the observatio that for efficient operation of a cyclone separator of the type described in US 4,237,006 it is necessary C to provide a certain resistance to flow at the underflow outlet of the separator.

The invention provides a cyclone separator for treating a mixture of liquids to separate a more dense component from a less dense component thereof, I. said separator having a separator chamber comprising first, second and third contiguous portions of circular cross-section and having an overflow outlet for the less dense component at the end of the first portion remote from the second portion and an underflow outlet for the more dense component at the end of the third portion remote from the second portion, the diameter of the separator decreasing from the first portion to the second portion and from the second portion to the third portion, the first portion comprising an inlet chamber with tangential t r 1 ir t 4 feed inlet means proximate to said overflow outlet, the second portion tapering over the whole of its length, and the underflow outlet being arranged to provide a resistance to flow therethrough from the third portion such that the flow through the underflow outlet expressed as a percentage fl/f x 100, where fl represents the restricted flow through the underflow outlet and f 2 represents the i, flow from the outlet of the third portion in the absence of any restriction to flow in the underflow Wi outlet, lies within the range of from 10 to 93%.

i t L, I ir S The invention is further described with reference to the accompanying drawings in which: Figure 1 is a cutaway perspective view of a cyclone separator constructed in accordance with this invention; Figure 2 is a fragmentary lengthwise section of a modified cyclone separator in accordance with the invention; Figure 3 is a fragmentary lengthwise section of another modified cyclone separator in accordance with the invention; Figure 4 is a scrap view corresponding to ,L part of Figure 3, but showing the separator in use.

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6 Figure 5 is a fragmentary perspective view of the cyclone separator of Figure 1 showing outlet area varying means in accordance with the invention; Figure 6 is a view like Figure 5 but showing the outlet area varying means operated; Figure 7 is a cross-section showing part of the cyclone separator of Figure 5, and outlet thereof, and the area varying means when conditioned in the same condition as Figure Figure 8 is a view like Figure 7 but showing the outlet area varying means in the condition of Figure 0 00000 00 0 09 0t 0 1 0 000t*0 O *0 00 0 0 00 *0 0 0 0 0 Figure 9 is an electric circuit diagram of electric control means associated with the area 15 varying means; Figure 10 is a partly sectioned perspective view of an alternative form of area varying means constructed in accordance with the invention, Figures 11 and 12 are cross-sectional views of the area varying means of Figure 10 shewn, respectively, in closed and open conditions, Figure 13 is a side view of a still further form of area varying means constructed in accordance with the invention, _li_ -i-

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7 Figure 14 is an end view of the area varying means of Figure 13, Figure 15 is a plan view of the area varying means of Figure 13; Figures 16 and 17 are respective axial cross-sections of the area varying means of Figure 13, in two different operative conditions, i, Figure 18 is a graph illustrating influence of |i outlet constriction on separating performance of the separator of Figure 1, Figure 19 is a graph illustrating influence of outlet constriction on delivery flow from the separator of Figure 1, Figure 20 is a diagram showing interconnection of 15 two cyclone separators, in accordance with this invention, CC Figure 21 is a fragmentary axial cross section showing an alternative form of overflow outlet pipe for the cyclone separator of Figure 1, Figure 22 is an end view of a bank of separators as shown in figure 1, Figure 23 is a diagrammatic opposite end view of one row of separators in the bank of separators shown in Figure 22, and Figure 24 is a diagrammatic cross section of the bank of separators of Figure 22, taken approximately on the line 24-24 in Figure 22.

The separator 10 shown in Figure 1 has a separating chamber 25 in the form of an axially extending surface of revolution having first, second I and third portions 12, 14 and 16 coaxially arranged in that order. The first cylindrical portion 12 has two feed pipes 26, 28 associated therewith, these being arranged to feed tangentially into the portion s 12 via respective inlet apertures of which only one aperture, namely aperture 30 associated with pipe 26, is visible in the drawing. The two feed inlet I apertures are diametrically arranged one relative to Sthe other and positioned close to the end of portion 12 remote from portion 14. The end of portion 12 remote from portion 14 also has a circular outlet opening 32 which leads to an overflow outlet pipe 34.

I Portion 12 is not of constant diameter over its whole length, the part 12a thereof adjacent portion 14 exhibiting a taper towards the second portion 14.

The second portion 14 exhibits a taper over its length, tapering from a diameter at the end adjacent section 12 equal to the diameter of portion 12 at the junction between the two portions to a somewhat lesser dimension at its opposite end.

L i i ~-amra~UC~~~-PI Portion 16 is a constant diameter equal to the minimum diameter of portion 14.

In the drawing, the length 11 of portion 12, its diameter d 1 the taper angle a of the tapered part of cylindrical portion 12, the internal diameter d o of the outlet pipe 34, the length and diameter 12, d 2 of the second portion 14, the taper angle 3 of the second portion 14 and the i length 13 and diameter d 3 of the third aa; *cylindrical portion, as well as the total area A.

j4,' of the two feed inlet apertures 30 may all be t t selected in accordance with the parameters mentioned (,tS in United States patent 4,237,006 save that the outlet diameter d o need not constrained to be within limits as described therein, 4 4 o°'o In accordance with this invention, a fourth portion is added to the separating chamber 25, this portion being designated by reference numeral 18 in Figure 1.

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Portion 18 has a part 18a adjacent portion 16 which is of frustoconical configuration, tapering from a maximum diameter equal to d 3 at its end closest to and adjoining to the outlet end of cylindrical portion 16, to a diameter d 4 at its outlet end. At the outlet end of part 18a fourth portion 18 includes an outlet pipe 18b which is of internal diameter d 4 Preferably, the angle a being the conicity or half-angle of the frustoconical surface of part 18a is about 450, although angles in the range 300 to 600 are generally satisfatory. In any event, it is preferred d4 that the ratio Ty be in the range 1:3 to 2:3. The l1ength of part 18a is not critical to the invention and in any event is normally fixed by the selection of the aforementioned ratio of diameters d 4 to d 3 Likewise, the length of the pipe 18b has not been found to be important to the operation of the invention.

Although part 18a is shown as having a truly frustoconical cross-sectional form (that is to, say it is shown as havi~ng a side surface which exhibits a linear sloping configuration relative to the axis of the portion when viewed in section) this is not essential. The part 18 may have a conicity angle which varies along the length thereof such as either increasing or decreasing the direction from the 47;41'greater diameter end to the lesser diameter end thereof It is preferred that the 11 length of the part 18 be roughly the same as the maximum diameter thereof.

In use, liquid to be separated is admitted tangentially to the interior of' portion 12 via feed pipes 26, 28, the denser component of the liquid then travelling lengthwise through the separator to emerge from pipe 18b, whilst the lighter component emerges from pipe 34.

t Figures 18 and 19 show experimental results obtained by operating an experimental oil separator of the form shown in figure 1 with various fourth portions 18 presenting different end diameters d 4 The third portion 16 of this separator had a diameter d 3 of 29mm. Under operating conditions, with the fourth portion 18 removed, the exit flow rate from the separator when separating an oil-water mixture was 200 litre/minute. The experimental separator was tested using a mixture of oil and water with the oil concentration being approximately 7500 p.p.m.

20 As shown in figure 18, the separating action of the separator was found to be heavily dependent on the exit diameter d 4 Only when diameter was reduced to d4 give a ratio d of 80% or less did the residual oil concentration in water exiting from the portion 18 exhibit a magnitude (130p.p.m) which was judged satisfactory. Further decrease in the ratio a brought about a corresponding decrease in residual oil concentration until a minimum residual concentration 12 of about 35p.p.m. was achieved at a diameter ratio of about 76%. Further decrease in the diameter ratio caused decreased separation efficiency, the residual oil concentration rising with diameter ratio decrease until a diameter ratio of about 66% wos reached, at which the residual oil concentration was about d4 130p.p.m. On further decrease in the ratio a3 the residual oil concentration again fell, the concentration being about 45p.p.m. at a ratio of d4 The aforementioned range 1:3 to 2:3 for the ratio represented in figures ,8 and 19 as range R

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has been found satisfactory in many applications giving good separation, whilst ensuring reliable operation, where operating considerations do not require maintenance of highest flow rates through the separator. As shown in figure 19, the flow rate through the experimental I' 4, separator was found to exhibit relatively small fall d4 off where the ratio a- was large. However the flow rate falls rapidly once the ratio falls below about 55% at which ratio the flow rate was found to be one half of that prevailing when no fourth port$on 18 4 was provided. The lower limit of the range P ratio U- is established at 33% based on t observation that below this ratio insufficient tivw could be achieved through the separator for effective operation to occur. As evident from figure 19, the d4 flow rate at this value for a was about litre/minute in the experimental separator giving a flow rate of some 10% of the flow rate with no portion 18 provided. The preferred upper limit of 662/3 for

R

1 is 13 established on the basis that although good separating operation can be achieved above this level, care in operating is necessary to ensure that transitory fluctuations in flow do not cause higher levels of retained oil. Notwithstanding this, however, it has been found that where efficient separation is needed together with preservation of high flow through the separator, operation in the range R 2 shown for the d42 ratio a is preferable. The loyer limit for Range

R

2 is established at a value of a equal to being the value at which the flow rate is still one half of that prevailing with no portion 18 provided.

The upper limit for range R 2 is established at a value of ratio d4 equal to about 80%, this representing the maximum value at which adequate oil separating efficiency is retained. At this ratio, the flow rate through the experimental separator was largely unaffected by the presence of portion 18, being about 185 litre/minute or some 93% of the original rate, as evident from figure 19. At that ratio, the residual oil concentration was as mentioned d4 about 130p.p.m. Thus, the overall range of ratios for poscible operation is the ralige R 3 shown, extending trom about 331/ to about 80%. The ranges 3 RI, R 2

R

3 may alternatively be expressed in terms of ratios of cross sectQnol areas of the portions 18 and 16 as ratios (a3)2 Figure 19 has a scale marked in area ratios from whicd the area ratios corresponding to given r;Atios may be ipproximated. The ranges R 3 when so expressed id 4 2 in area ratios T3 i-i 14 have the following limits: Rd4 2* R2 (d4 )2 10% to 30% to 10% to R3 d 2

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'j ii .i g V d4 d4 2 5 Furthermore, the ratios -3 and dy are measures of the resistance to flow through portion 18. This resistance may also be expressed as a fl percentage 2- of the flow which would prevail if no portion 18 were provided, "fi" representing the flow with portion 18 and f 2 the flow when there is no portion 18. The ranges R 1

R

2 and R3 have the following limits, ascertainable from figure 19, when expressed in terms of such percentage flow: R f R 22 fl 15 R2; r R 3 7to/% 50% to 93% 10% to 93%.

E The modified cyclone separator 110 shown in Figure 2 is identical to that shown in Figure 1 save that the pipe 18b is omitted and a modified fourth 20 portion 118 is provided instead of portion 18.

Portion 118 is of the same diameter as portion 16 but is filled with sand particles 119 whereby to provide resistance to flow therethrough. The size and density of packing of sand particles and the length of portion 118 are selected to provide a resistance to flow similar to that provided by portion 18.

Where the separator 110 is vertical, the sand may be supported on a suitable meshing such as the meshing 121 shown. Otherwie suitable retaining meshing may be provided at either end of portion 118.

In a still further alternative construction (not shown) resistance to flow through portion 118 is provided by partial flattening of portion 118 or by retaining a suspended ball in a cage therein.

In the modification shown in Figures 3 and 4, the pipe 18b is formed of a flexible tube. A' pressure sensor 140 is provided connected to be sensitive to fluid pressure at the inlet end of the pipe 18b and to provide an electrical signal at its output which is 8 representative of that pressure. A control circuit 142 is connected to receive signal from sensor 140 and to provide an output signal which is coupled to an electromechanical transducer 144 via lines 146 as *E shown. Transducer 144 might, for example, ba in the iform of a solenoid but in any event is of a kind having an element 148 which is capable of movement under control of the control circuit 142 so as to adopt a position which is dependent upon the fluid pressure as sensed by sensor 140. Element 148 is disposed to one side of the tube comprising pipe 18b and a fixed element 150 of somewhat similar

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configuration is provided immediately opposite element 148 and to the opposite side of the tube defining pipe 18b. The arrangement is such that, on detection of decrease of fluid pressure as sensed by sensor 140, 5 control circuit 142 controls transducer 144 to move element 148 inwardly towards element 150 to constrict the pipe 18b, by deformation of the wall of the tube thereof as shown in Figure 4. Thus, on detection of fluid pressure decrease, the cross-sectional area of pipe 18b is decreased. Correspondingly, if increase of pressure is detected by sensor 140, control circuit 142 moves element 148 away from element 150 to release the constriction to some extent. By this means, the resistance to flow presented by the pipe 18b can be varied in accordance with the determined pressure at the inlet end of the pipe 18b.

i The above described arrangements for providing restriction to outflow from the separator have been found to be effective in ensuring adequate operation of the separator. More particularly, in the absence of such constriction, it is observed that, generally, the outflow via portion 16, which should, for effectiveness of the separator, comprise only the more dense component of the liquids to be separated, will tend to be contaminated with the lighter component liquid. It is believed that this effect arises because it is necessary to provide a "bac.

pressure", by inducing flow restriction, for outflow via portion 16 and the described constrictions effectively provide such back pressure.

In cases where two or more separators are coupled in series it has been found sufficient that the second separator only be provided with a specific flow restriction device since the second separator itself can satisfactorily act as a flow restriction device for the first separator. Figure 20 shows two separators 300, 312 of which separator 312 is of the form shown in figure 1. The feed pipes 26, 28 for Sseparator 312 are however coupled by a branched pipe 10 308 to the outlet end of a separator like the separator of Figure 1, save that the S* portion 18 is omitted. In use oil-water mixture is introduced first into separator 300, separated oil leaving via outlet 34 thereof. The water component, possibly still with some oil content, is taken from the outlet of the separator provided by portion 16 thereof via pipe 303 to the separator 312.

Further oil is separated by the separator 312, leaving via the outlet 34 thereof. Water is exited from 20 separator 312 via portion 18 thereof. In this arrangement, separator 312 provides the flow restriction necessary for proper operation of separator 300.

0 ad As best shown in Figures 5 to 8, the outlet pipe 34 of the separator of figure 1 may be provided with an area varying means 23 constructed in accordance with this invention. More particularly, the area A varying means includes a segment 29 of the pipe 34 Swhich is constructed so as to be removable from the remainder 31 of the pipe 34. Segment 29 has part

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frustoconi(cl end surfaces 33, 35 which in the closed condition of the segment shown in Figures 5 and 7 mate with corresponding part frustoconical surfaces 36, 38 of the remainder 31 of the pipe 34. The segment 29 also has two opposed side edge surfaces 40, 42 which mate with corresponding lengthwise extending edge surfaces 44, 46 on the pipe remainder 31.

Ir A rod 48 is connected to the exterior of segment p 29 and extends away therefrom at an angle relative to the axis of pipe 34, this angle corresponding roughly to the antle of surfaces 33, 35 as presented to the axis of the pipe 34 in a generally radial plane in which the rod 48 is contained. At its opposite end, rod 48 is connected to the plunger 50a of an electromagnet 50. A spring 54 is interposed between the body of the magnet 50 and an outstanding flange 48a on rod 48 and normally urges rod 48 away from the electromagnet 50 to the condition shown in Figures and 7 at which the segment 29 neatly fits into the space in the pipe 34 defined by the surfaces 36, 38 44 and 46. Although not shown, in order to facilitate sealing, the surfaces 33, 35 of the segment 29 may be made slightly convergent in the direction away frnm the outside surface of the segment 29 towards the axis of the pipe 34, Similarly, the surfaces 40 and 42 may be made convergent in the direction away from the outer surface of the segment 29 towards the axis of the pipe 34.

19 In the condition of Figures 5 and 7, the cyclone separator can operate normally, one of two components of the liquid admitted via pipes 26 and 28 being delivered, as previously described, from the r portion 12 through the outlet constituted by the pipe 34 and its interior opening 34a with the interior of portion 12.

The liquid flow under these conditions is shown by Iarrows 56.

i 10 Under the condition that the outlet constituted Sby pipe 34 and outlet opening 34a should become j blocked, it is possible, by energizing of electromagnet 50, to withdraw the rod 48 into the body of the electromagnet against the resilient bias applied by spring 54. Under this condition, then, the segment 29 is correspondingly moved outwardly of the remainder 31 of the pipe 34 so that an enlarged opening 68 then defined by the aforementioned surfaces 36, 38, 44, 46 is provided for egress of material from I 20 the separator. By this means, obstructions such as stones or the like may be readily cleared from pipe 34 ,Q and/or opening 34a. The flow of such egress is indicated by the arrows 70 in Figures 6 and 8.

In order to provide for automatic operation, the area varying means of the invention may, as shown in Figures 7 and 8, include a flow sensitive device 72.

Device 72 includes a light planar vane 74 positioned within pipe 34 and connected to a shaft 76 which is mounted for free rotation in a bearing (hot shown) in the side wall of the pipe 34. Shaft 76 extends, from an inner end within the pipe 34, exteriorly of the pipe 34. The shaft is mounted so that it is rotatable about an axis which extends generally radially to the shaft 76 has two radial arms 78, 80 which extend oppositely therefrom. Arm 80 is located adjacent a free end of an operating button 90a of a switch Arm 78 is connected, at its end remote from shaft 76, to a tension spring 92. Spring 92 is arranged to normaily bias arm 78 and shaft 76 to a position such that arm 80 assumes the position shown in Figure 8 at which the arm 80 is positioned at a limit distance away from the body of the switch 90. The operating button 90a of the switch 90 is resiliently biased away from the body of the switch and thus, at this condition, is at an extreme extension from the body.

Under this condition, the switch 90 is closed. It will be noted from Figure 8, too, that the vane 74 is so located, relative to the shaft 76 that under the condition of Figure,8 the vane does not extend in the axial direction of the pipe 34 'but is angularly Sdisplaced relative thereto.

Under the condition of flow through pipe 34, the flow so acts on vane 74 as to cause the shaft 76 to be rotated to the condition shown in Figure 7. During this rotation, which occurs against spring bias of spring 92, the arm 80 is brought to bear on the button 90a so as to axially move the button towards the body 21 of switch 90 at which condition the switch 90 is arranged to 'be open.

As shown in Figure 9, the switch 90 is arranged in an electric circuit 94 so that when closed it operates to effect energization of a relay coil 94a from a low voltage source 96. Electric contacts associated with a relay coil 95a are likewise arranged in an electric circuit 98 so that when closed the contacts ensure energization of the winding 50b of electromagnet 50 from an electric source 100. The arrangement is such that, under normal conditions of flow through pipe 34, switch 90 is not actuated, the vane 74 assuming the position shown in Figure 7.

Under conditions of flow blockage however, there will be reduced flow through pipe 34 with the result that there is insufficient fluid pressure to maintain the vane 74 in the generally axial direction of the pipe 34, against the bias of spring 92, whereupon the spring 92 operates as just described to rotate the shaft 76 and thereby effect closing of switch Resultant operation of the electromagnet 50 causes withdrawal of the plunger 50a, so conditioning the means 23 as shown in Figure 8 to permit clearance of the blockage. After clearance as shown in Figure 8, resumption of flow through the pipe 34 will occur and the apparatus will be conditioned again to the crndition of Figure 7. In order to facilitate reversion back to the condition of Figure 7, it is possible to modify the circuit of Figure 9 to include timing and resetting means such that the contacts it. Le] 22 remain closed only for a predetermined time following an initiation of closing pursuant to closing of switch Referring now to figure 10, a modified area varying means 124 is shown for use in conjunction with an outlet pipe 120 of a cyclone separator 110. The separator 110 is, aside from the different form of the area varying means similar to the separator previously described, the outlet pipe 120 corresponding in function generally to the outlet pipe 34 previously described, and extending away from an outlet opening 122 generally performing the same function as the outlet opening 34a previously described.

The pipe 120 has a movable portion 128 which forms one segment of the total periphery of the pipe and which is pivotally secured to the remainder 130 of the pipe. Remainder 130 is secured, such as by welding, to the end wall 125 of the separator, about opening 122. Portion 128 is pivoted, at a location downstream of opening 122, to the remainder 130 of pipe 120 by coaxial pivot pins 127, 129 which extend through lugs 131, 133 on the pipe "remainder. At locations adjacent the outlet 122, the remainder 130 and pipe portion 128 are of generally arcuate configuration when viewed in cross-section, fitting together, in the operative position of the means 124, in the fashion shown in Figures 10 and 11 to define a substantially circular cross-sectioned flow path for fluid flow from outlet 122. As shown in Figure 12, however, the portion 128 is swingable about the common axis of the pins 127, 129 so that, adjacent the opening 122, the portion 128 is swung outwardly to increase the space between the portion 128 and remainder 130 of pipe 120 so increasing the outflow area and permitting clearance of blockages.

A light helical tension spring 135 is provided between the lower end of portion 128 and an outer flow collecting pipe 145 secured to separator wall 125 in coaxial spaced relationship around pipe 120. Spring 135 provides a resilient bias so directed as to tend to cause the portion 128 to assume tho open condition shown in Figure 11. However, in normal use, with fluid flow through outlet 122 into the pipe 120, the portion 128 is held biased in its closed position by S. fluid pressure force acting on a lever 147. Lever 147 has two arms 149, 151 each radiating from a central portion of the lever. The lever is pivotally mounted to the pipe 145 at that central portion by means of a pin 153 passing through lugs 155 on the interior surface of the pipe 145. Arm 151 extends generally against the flow direction in pipe 130 from pin 153 to an outer end which engages the exterior of portion 128 at a location well away from its pivot axis about pins 127, 129. Arm 149 extends away from pin 153, through a clearance slot 159 in portion 128 and thence A /generally transversely across the interior of the pipe a, 120 between the port'on 128 and the remainder 130 of the pipe.

24 In the absence of flow from outlet 122 through pipe 120, lever 147 is positioned as shown in Figure 12, with the free end of the arm 151 against the exterior surface of portion 128. However, when flow occurs through the pipe 120 the flow impinges upon the arm 149 of lever 147 thus subjecting it to a pressure force which is directed away from the opening 122 in the direction of flow of the liquid through pipe 120.

The force is arranged to be sufficient to cause movement of the arm 149 and thus of the lever 147 so that the lever is pivoted in the clockwise direction from the position as shown in Figure 12, so that the pressure force acting on arm 149 is transferred through the lever to apply a force at the opposite end thereof, namely at the free end of arm 151, against portion 128 thus causing the portion to be pivoted, with corresponding pivotal movement of the lever 147, to close the gap between the portion 128 and the remainder 130. That is to say, the action is thus to move the portion 128 from the condition shown in Figure 12 to that shown in Figure 11, against the bias of spring 135. By this means, in normal use, the portion 128 is maintained closed, only opening under condition where, due to blockage, there is no flow through the pipe 120 whereupon the pressure force acting on arm 149 is reduced to the extent that the spring 135 can operate to bias the portion 128 open.

This arrangement has the advantage that it has no electrical parts and is mechanically simple, whilst nevertheless operating automatically to increase the area for outflow of the fluid under blockage conditions and to again decrease the area for outflow to a normal condition on clearing the blockage.

Referring now to Figures 13 to 17, the modified area varying means 224 shown therein is for use in conjunction with an outlet pipe 220 of a cyclone separator, such as the separator 10. The outlet pipe 220 performs the function of the earlier described outlet pipe 34. The area varying means 224 has a circular plate 221 adapted for securement to a transverse end wall of the separator so that an outlet opening 222 through the plate 221 and le.ding to the interior of the pipe 220 then performs the function of the previously described outlet opening 34a.

Pipe 220 has a removable portion 228 which forms one segment of the total periphery of the pipe and which is pivotally secured to the remainder 230 of the pipe. The pivotal securement is effected by means of two lugs 233, 235 secured to the portion 228 and pivoted to the pipe remainder 230 by means of pivot pins 237 arranged on a common side-to-side pivot axis on the remainder 230. The pipe 220 has an interior bore extending from opening 222 to an outlet aperture 271 at the end of the pipe remote from plate 221, As best seen from Figures 16 and 17 this bore has two sections, a larger diameter bore section 273 adjacent opening 222 and a lesser diameter section 275 adjacent aperture 271. Remainder 230 of pipe 220 is formed with lengthwise extending surfaces 279, 281 which are disposed to opposite sides of bore section 275 and I2 portion 228 has corresipondc lon~thwise extending surfaces 283, 285 which, iln the ot ,ed condition of the area varying means, sealinqy OngAge the respective surfaces 279, 281. The bore section 275 is, for one lengthwise exten4<y h~lf thereofI defined within remainder 230 and for the other lengthwise extending half, defined with.in portion 228. At a portion of the larger diameter bore section 273 adjacent the junction between sections 273 and 275, the portion 230 has a transverse, planar, somewhat U-shaped surface 287 which extends, at opposite ends of that surface, to meet respective ones of the surfaces 279 and 281 and thence extends obliquely to the top of the outer surface of the remainder 230 as viewed in the sections of Figures 16 and 17. The U-shaped configuration of the surface 287 can, however, be appreciated from Figure 15. The portion 228 has a similar U-shaped surface 289 which in the closed position of the area varying means engages with surface 287.

Plate 221 carries a. generally U-shaped bracket 290 and a shaft 292 extends between the opposed arm 2' portions thereof and is retained therein so as to be freely rotatable about an axis extending transversely of the pipe 220 and generally parallel to the plane containing surfaces 279, 281. Shaft 292 has secured thereto two elongate arms 294, 296 which extend away from the shaft to free ends positioned over the end of 'A pipe 220 remote from opening 222. A plate 297 is secured to the free ends of the arms 294, 296 and ,w- 27 extends generally transversely thereto t the directionz, of extent of the arms. Intermediate the ends of the shaft 192, the shaft is provided with a d,.'nwardly depending cam element 298 which is secured for rotation with the shaft. Cam element 298 has a lower cam surface 298a which is of arcuate form and which co-operates with an arcuately curved cam surface 300a on a projection 300 extending upwardly from portion 228.

In normal operation of the device 224 the portion 228 occupies the 2osition shown in Figures 13 and 16 where the portion 228 i engaged with the remainder 230 so as to fully define the two bore sections 273, 275. Liqui4 leaving the cyclone separator passes through opening 222 thence through bore section 273 and then through bore section 275 t& exit via aperture 271. The bore section 275 is of relatively small diameter to provide proper operation of the separator.

Liquid egressing from aperture 271 strikes plate 297 and exerts sufficient force thereon to normally cause the arms 294, 296 to pivot such that the plate 297 is 1" held away from the aperture 271, as shown in Figure 13. Under this condition, the cam surface 298a on levnt 298 engages cam surface 300a on portion 228 in such a fzshid as to cause force exerted by the egressing liquid on the plate 296 and transferred through the arms 294, 296 to the element 298, to press on the portion 228 so maintaining it in the, position of Figures 13 and 16. Under the condition, however, where blockage of outlet 222 occurs and there is -li. I -~liil'--ii 'II i lj.- -I_~--l._llylllll.i~--~r_ 28 reduced flow through the bore sections 273 and 275, the force exerted by li, id emerging from aperture 271 will be insufficient to maintain the plate 297 clear of the aperture whereupon arms 294, 296 pivot clockwise as shown in Figure 13 so that plate 297 moves downwardly as viewed in Figure 13. This causes the cam surface 298a to be moved, by corresponding clockwise pivoting of element 298, away from cam surface 300a, thus removing constraint against pivoting of the portion 228 about the axis of pins 237. Under this condition, then, liquid pressure in the 're section 273 may bear against the portion 228 in such a fashion as to effect anti-clockwise pivoting of portion 228 as viewed in Figure 13 so as to bring portion 228 to the condition shown in Figure 17 whereupon the surfaces 279, 281 and 287 on remainder 230 of pipe 220 are well cleared from the corresponding surfaes 283, 285 and 289 on portion 228, so as to present a substantial gap therebetween, r* 20 such gap being indicated by reference numeral 295 in Figure 17. Thus, material causing a blockage in the outlet 222 may be readily cleared by outflow of liquid St through that gap. Once such clearance has occurred, the portion 228 may revert to the initial condition shown in Figure 16 under gravitational action, accompanied by clockwise rotation about the axis of the pins 237. If desired, in order to facilitate the return action,, a resilient tension spring may be provided acting between portion 228 and remainder 230.

Alternatively, in order to facilitate the action of the cam surface 298a, a spring may be provided between 29 i the projection and say, the plate 221 to lightly bias the element 298 for clockwise rotation about the axis of shaft 292.

In order to improve sealing between portion 228 and remainder 230 of pipe 220, the surfaces 279, 281 and 237 thereof may have suitable sealant strips positioned therein. Two such strips, designated by respective reference numerals 301, 303, are shown in Figure 14 as set into surfaces 279, 281. The strips may be formed, for example, of neoprene.

Figure 21 shows a modified overflow outlet pipe 34 usuable instead of the overflow outlet pipe 34 in the construction of figure 1. In this case the pipe has a stepped interior bore leading from outlet opening 32. More particularly, the bore has a first portion 34' adjacent outlet 32 of diameter equal to the diameter of outlet 32 and a second portion 34" away from outlet 32 of lesser diameter than bore portion 34'. Bore portion 34' may be of diameter in the range0.125 to 0.625 preferably 0.17 to 0.47 times the diameter d of portion 12 of the separating chamber 25. Bore portion 34" may be of diameter 0.015 to .05 preferably .025 to .035 times the diameter d1 of portion 12 of the separating chamber 25. The lengths of the bore portions 34' aid 34" are not important.

Figures 22 to 24 show an arrangement of sixteen separators 10 and 10' <n a bank 370. These are r e arranged in two vertical rows 372, 374 of eight separators each. A single main inlet feed pipe 376 is provided, this having three upright parallel secondary feed pipes 378, 380, 382 extending therefrom at spaced locations along the length thereof. The inlet pipep 26, 28 of four of the separators, separators 10, in row 372 are connected respectively to pipes 378 and 380 whilst the inlet pipes 26, 28 of four of the separators, also separators 10, in row 374 are connected respectively to pipes 380, 382.

The separators 10' are arranged four in each of the two rows 372, 374, three between each adjacent pair of separators 10 in the row and one above the uppermost in each row. The separators 10' are arranged with their outlet ends of their portions 16 oppositely directed to those of the separators The separators 10 and 10' in this case are not ,provided with fourth portions 18 but are arranged with the third portions 16 at the outlets thereof.

«As is best seen from figure 24, the portions 18 of the separators 10 are connected by branched pipelines 390 to the inlet pipes 26, 28 of the separators A0'. In the case of the uppermost three separators 10 in each row 372, 374, the portion 16 of each extends via the associated branched pipeline 390 to communicate with the inlet pipe 26 of the separator immediately above and the inlet pipe 28 of the 31 separator 10' immediately below. The lowermost separator 10 in each row provides communication via the pipeline 390 thereof with the inlet pipe 20 of the separator 10' immediately above and with the inlet pipe 28 of the uppermost separator 10'. The last mentioned pipeline 390 for each row is thus longer than the remaining pipelines 390.

The outlets at portions 16 of separators 10' in row 372 are connected to a common outlet line 398. A similar outlet line 400 interconnects the outlets at portions 16 of separators 10' in row 374 and these outlet lines 398 and 400 may be connected together as shown. Although not shown, for clarity, the outlet pipes 34 of all of the separators 10, 10' in both rows may be connected to a common line.

In use of the bank 370, oil-water mixture is fed to the main inlet feed pipe 376 and thence via the secondary feed pipes 378, 380, 382 to the separators in each of the rows 372, 374. This then flows through separators 10 of each bank. One half of the separated water component from each separator appearing at the outlet of portion 16, is then fed to a separator 10' in that row, whilst the again separated water from the separators 10' is taken from the bank via the lines 398, 400. Separated oil emerging from the separators 10, 10' is collected sich as in a single collector pipeline. By this arrangement, oil-wtter mixture is passed in succession through to separators before reaching the water outlet I i i _L 7 7 32 from the bank. This arrangement has been found to be very satisfactory in use.

In the described arrangement, although no specific provision is provided to generate back pressure in the separators 10, 10' so as to cause flow constriction, such back pressure and flow restriction is provided, for the separators 10, by *o the separators 10' themselves which are connected to the portions 16 of separators 10, and, for the separators 10', by the outlet lines 398, 400 which are suitably dimensioned for the purpose. If necessary, however, a common flow constriction device could be inserted at an outlet pipe providing connection to both of lines 398, 400.

The described arrangement has been advanced merely by way of explanation and many modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims.

i i i

Claims (29)

1. 2. A cyclone separator according to claim 1, wherein the half angle of the second portion lies in the range of from 20' to
2. 3. A cyclone separator according to claim 1 or claim 2, wherein the restriction to flow is provided W 1 P 34a by a fourth portion of the separating chamber, being of restricted diameter compared with the outlet diameter of the third portion such that the ratio of the minimum diameter of the fourth portion to the diameter of the third portion at its outlet, expressed as a percentage, lies in the range of from 33 1/3 to
3. 4. A cyclone separator according to claim 3, wherein said ratio, expressed as a percentage, lies in the range of 33 1/3 to 66 2/3%. A cyclone separator according to claim 3 or claim 4, wherein said fourth portion is connected to said third portion by a frusto ~ii~F~ :j i E i I tj i, j i 35 conical section.
4. 6. A cyclone separator according to claim 1, wherein said resistance to flow is provided by porous flow resistance means in the underflow outlet.
5. 7. A cyclone separator according to claim 1, wherein the underflow outlet is provided with flow inhibiting baffles or other flow resistance elements.
6. 8. A cyclone separator according to claim 1, wherein the underflow outlet is provided with a flexible wall in a tubular portion thereof with means for exerting external pressure on the wall to effect deformation thereof whereby the resistance to flow is variable within said range.
7. 9. 'A cyclone separator according to claim 8, wherein control meand are provided for sensing liquid pressure in the cyclone separator and for varying the degree of resistance to flow responsive to the sensed pressure. A cyclone separator according to claim 9, wherein the control means are responsive to decrease flow resistance when there is a rise in sensed pressure and to increase flow resistance when there is a drop in sensed pressure.
8. 11. A cyclone separator according to any one of claims wherein the length of the second portion is at least 10 maximum diameter. 1 to times its
9. 12. A cyclone separator according to any one of claims 1 to 11, wherein L /d2 2 0.04 4A /Td 2 0.10 d1 d d 2 d3 r 1 i: i 36 wherein, d I is the diameter of the first portion at the level of the feed inlets, d 2 is the maximum diameter of the second portion and d 3 is the diameter of the third portion at its outlet, 12 is the length of the second portion and, A 1 is the total cross-sectional area of the feed inlet means measured at entry into the separating chamber normal to the inlet flow.
10. 13. A cyclone separator according to claim 12, wherein:- S0. do/d 2 0.25 wherein d o is the diameter of said overflow outlet.
11. 14. A cyclone separator according to any preceding claim, wherein the overflow outlet is pj 1 ovided with means selectively operable to vary the cross-sectional area of the outlet for permitting clearing of a blockage occurring in the outlet. A cyclone separator according to claim 14, wherein flow sensitive meal,, is provided, positioned and operable for detecting a decrease in flow through said outlet and for operating said area varying means for increasing the cross-sectional area for said clearing.
12. 16. A cyclone separator according to claim wherein said outlet is in the form of an outlet pipe and the cross-sectional area varying means comprises a mechanism including a portion of the wall of the pipe which is so movable as to open the side of the pipe to the exterior thereof. 36a
13. 17. A cyclone separator according to claim 16, wherein said portion is a side segment of the pipe which is movable outwardly away from the remainder of the pipe under influence of said mechanism. i 37
14. 18. A cyclone separator according to claim 16 or claim 17, wherein said mechanisn includes an electromagnet and the said flow sensitive means operates to apply electric current to said electromagnet for effecting movement of the wall portion away from the remainder of the pipe on sai4 detecting of decrease in flow.
15. 19. A cyclone separator according to claim 16, wherein the pipe wall portion is pivotally. movable away fiom the remainder of the pipe. A cyclone separator according to claim 19, wherein the pipe wall portion is arranged to be subject, in use, to a bias towards a position effecting said ooening of the side of the pipe, and said a flow sensitive means is positioned to be normally acted upon directly by flow through the pipe to inpart a force thereon which is *directed against the outlet pipe wall portion to maintain it closed, sa id force, however, being reduced fn the cane of reduced flow through the pipe due to blockage whereby the aforementioned bias effects movement to open the side of the pipe.
16. 21. A cyclone separator according to claim 20, wherein the flow sensitive means comprises a pivotal lever having two arms extending from a location at which the lever is pivotal to said remainder of S* said pipe, one said arm being formed with means in use subjected to flow thereonto from the separator and the other engaging the said pipe wall portion.
17. 22. A cyclone separator according to any one of claims I to 21, wherein said overflow outlet presents a stepped bore with a first bore oortion adjacent the first portion being of greater diameter than a second bore portion thereof further from the first portion.
18. 23. A cyclone separator according to claim 22, wherein said first bore portion is of a diameter in the range 0.125 to 0.625 of the diameter d 1
19. 24. A cyclone separator according to claim 22 or claim 13, wherein r. 38 said second bore portion is of diameter 0.015 to 0.05 times the diameter d I A cyclone separator according to claim 1, substantially as described herein with reference to the drawings.
20. 26. A cyclone separator assembly comprising two cyclcne separators in accordance with claim 1 arranyed in series with the underflow outlet of the first separator connected to at least one of the inlets of the second separator, the second separator providing said resistance to flow from the underflow outlet of the first separator.
21. 27. A cyclone separator assembly according to claim 26, substantially as described herein with reference to Figure 20 of the drawings. ,i 28. A cyclone separator bank comprising a plurality of cyclone separators in accordance with claim 1 arranged in a plurality of rows of separators, a main feed inlet pipe and a plurality of generally parallel secondary inlet pipes extending from the main inlet pipe at spaced locations along the length thereof, the rows of separators lying between adjacent pairs of secondary inlet pipes with one inlet of each separator being connected to one secondary inlet pipe and the other inlet of each 3separator being connected to the other secondary inlet pipe of the adjacent pair of secondary inlet pipes,
22. 29. A cyclone separator bank according to claim r 28, including a plurality of rows of second separators, the underflow outlet of each first separator being branched with one branch being connected to one inlet of a second separator and the other branch being connected to one inlet of an adjacent second separator, the second separators providing said resistance to flow from the nderflow outlet of the first separators. A cyclone separator bank according to claim 28, substantially as described herein with reference to Figures 22 to 24 of the drawings.
23. 31. A cyclone separator comprising elements designed, sized and arranged for treating a mixture of liquids and for separating a more dense liquid component from a les dense liquid component thereof, said separator comprising a separating chamber having a primary portion which has a greater cross-sectional diameter at one end than at its other end and further having an overflow outlet at said one end thereof and an underflow outlet at said other end; tangential feed inlet means proximate to said one end, said seirator further including means designed, sized and arranged for acting to preclude contamination of the more dense component emerging from the underflow outlet by the ;tess dense component, said means having an inlet end downstream of said other end of said primary portion with respect to the direction of flow of said separated more dense component, and an outlet end, said means presenting a passageway for throughflow of the more dense component, which passageway has a diameter at said outlet end thereof which is from 1/3 to 0.8 the diameter thereof at said inlet end thereof.
24. 32. A cyclone separator as claimed in claim 31 wherein said primary portion is of a length which is at least ten times its diameter at the plane of said feed inlet.
25. 33. A cyclone separator as claimed in claim 31 wherein said means is comprised by a secondary portion of said separating chamber at said underflow outlet.
26. 34. P cyclone separator as claimed in claim 31 wherein said primary portion comprises a first sretion and a second section contiguous therewith said overflow outlet being disposed at an end of said first section remote from said second section, said second section having said underflow outlet at an end thereof remote from said first section, said means being comprised by a third section at said underflow Soutlet. A cyclone separator as claimed in claim 31 wherein said primary portion comprises a frustoconical i.ection and said means is comprised by I a secondary portion of said separating chamber at said underflow outlet.
27. 36. A cyclone separator as claimed in claim 31 wherein said means includes an outlet pipe extending from the underflow outlet.
28. 37. A cyclone separator as claimed in claim'.* wheztin said outlet pipe has a substantially constat diameter. 41
29. 38. A cyclone separator substatntially as herein described with reference to the accompanying drawings. Dated this 12th day of January 1988 C ci g #0 C *0 C 1 C C C a ci C ci I ci I NOEL--CARROLL By his Patent Attorneys DAVIES COLLISON