GB2205512A - Vortex separator - Google Patents

Abstract

A separator for removing heavy and/or light contaminates from fluids of the type which relies on the rate of delivery, and the direction of the incoming contaminated fluid to generate circulating flows within the separator vessel (12). Flow modifying members are provided in the vessel in the upper regions thereof, giving improved separation. Flow enters the vessel from a nozzle (40). A first flow-modifying member (22) creates an outer annular zone leading to an aperture (15) in the vessel lid (13) for discharging light contaminates. Another flow-modifying member (44), adjustable in height along the vessel axis, breaks up rising vortex flows thus preventing heavy contaminates from being carried up to the clean fluid outlet (17). Under control of a flow-meter (28) and control device (43), back-flow in the heavy contaminates discharge outlet (23, 26) can be automatically initiated to clear any blockages detected therein. <IMAGE>

Description

"IMPROVEMENTS IN on RELATING TO SEPARATORS" This invention relates to separators and has particular application to separators for removing solids particles from liquids.

In this specification the tern "heavy" contaminates shall mean contaminates having a specific gravity greater than that of the surrounding fluid, the term "light" contaminates shall mean contaminates having a specific gravity less than that of the surrounding fluid and the term "particulate" shall mean any body of gas, liquid or solids material having a different specific gravity from that of its surrounding medium.

Separators for separating solids particulate contaminates from gases and liquids are well known in the art and conventionally co.#prise a cylindrical vessel, arranged with its axis substantially vertical , with an inlet for the contaminated fluid, an outlet for the heavy contaminates (generally in tha lo#er regions of the vessel), and an outlet for the de-contaminated gas or liquid, generally in the upper regions of the vessel. Then the contaminated fluid is a liquid containing light particulate contaminates to be removed from the liquid the separator will include an outlet for the light particulates, generally in the highest region within the vessel.

The separation is effected by inducing circulating flows in the fluid in the vessel, substantially concentric with the vertical axis of the vessel, and whereby the circulating flows generate laminar flows within the fluid which assist the rise of the light particulates and the fall of the heavy particulates under gravity.

The circulating flows may be induced mechanically, as by stirring, or simply by the rate of the supply and the direction of release of the contaminated fluid into the vessel. The present invention is not concerned with such separators as rely on mechanical or electrical methods of inducing vibrations or flows in the fluid in the vessel and such separators are excluded from the scope of this invention.

The present invention is tnerefowe concerned solely with such separators as rely on the circulating flows being induced by the rate and the direction of the contaminated fluid being introduced into the vessel and such separators are, hereinafter, referred to as "separators of the type defined".

Separators of the type defined are, as stated above, well known in the art but one feature considered essential in all the prior art separators is the inclusion of a flow modifying member or members located in the lower regions of the vessel and intended to direct the heavy particulates falling within the fluid outwardly with respect to the axis of the vessel. By directing the heavy particulates outwardly in the lower regions of the vessel such prior art separators seek to prevent upward circulating flows on or adjacent the axis of rotation of the fluid from carrying heavy particulate contaminates to the clean fluid outlet.

By way of e#ple the British Patent No. 2082941 discloses a separator of the type defined for removing solids particles from liquid aeal includes a conical element supported in the lower regions of the vessel. According to that patent, solids particles falling through the liquid and onto the sloping surface of the cone are directed donsçardly and outwardly over the surface of the cone. The heavily solids contaminated liquid in the lower regions of the vessel flows radially inwardly, through an annular passage between the lower edge regions of the cone and the bottom wall of the chamber, before flowing to the outlet.

The cone is hollow, with an opening in its apex, and it is held in the patent that liquid within the cone, having deposited the -greater part of its solids contaminates, flows gently upwardly. through the cone and outwardly through the opening to prevent the natural vortex in the circulating liquid from extending downwardly into the heavily contaminated liquid and thereby inducing an upward flow of- heavy solids contaminates.

An object of the present invention is to provide a separator of the type defined which is relatively inexpensive in construction and can have a greater efficiency than prior art separators of the type defined.

According to the present invention there is provided a separator, of the type defined, comprising a vessel for containing fluid to be cleaned of particulate contaminates, means for introducing contaminated fluid to said vessel at such rate and with such direction as to induce flows, circulating about a substantially vertical axis, in the fluid in the vessel, a first outlet though which particulate contaminates can be removed from the vessel and a second outlet through which substantially de-contaminated fluid can be removed from the vessel, characterised in that such flow modifying members or elements as are provided to affect the movement of the fluid within the vessel are located substantially in the upper regions of the vessel.

Preferably all such flow modifying members or elements as are provided to affect the movement of the fluid within the vessel are supported by the roof of the vessel.

In one emi,odiment in accordance with the invention# said first outlet is in the lower regions of the vessel and allows heavy particulate conta-.#inates to be discharged from the vessel and said first and second outlet3 are concentric with the central axis of the vessel.

Preferably the separator includes a third outlet in the upper regions of the vessel, said third outlet is spaced from the central axis of the vessel and said third outlet allows light particulate contaminates to be discharged from the vessel.

Preferably the separator includes a flow modifying element comprising an annular skirt depending downwardly from the roof of the vessel, concentric with the axis of the vessel, and having an internal diameter greater than the diameter of said second outlet.

Preferably said third outlet opens through the roof of the vessel between said annular shirt and the wall of the vessel.

Preferably the separator includes a tubular flow modifying msm:?er, having an internal diameter substantially equal to the diameter of said second outlet, and which depends downwardly into the upper regions of the vessel concentric with the axis of the vessel.

?referably means are provided for axially adjusting the position of said tubular flow modifying member within the vessel.

Preferably tze separator further includes a circulating flow supprassion menber, located in said tubular flow modifying member, and comprising a core element, concentric with the tubular flow modifying member, with radial vanes extending therefrom.

In one embodiment in accordance with the invention the peripheries of the said vanes extend to the bore of said tubular flow modifying member.

In another embodiment the peripheries of the vanes have a clearance fit in the bore of said tu####ilar flow modifying member and means are provided for axially adjusting the position of said circulating flow modifying member relative to said tubular flow modifying member.

Preferably the separator includes a nozzle through which the contaminated fluid to be cleaned is released into the vessel, said nozzle being located in or by a side wall of the vessel substantially parallel to the central axis of the vessel and arranged to direct the fluid released therefrom generally parallel to the adjacent side wall and substantially at #i7#t angles to the axis of the vessel.

In a preferred embodiment the separator is characterised in that ducting, for conveying heavy particulate contaminates from the vessel, include valve means and a fluid supply by which a reverse flow of fluid can be released into said ducting to clear heavy particulate contaminate bloc'cages therefrom.

The invention will now be described further by way of example with reference to the accompanying drawings in which; Fig. 1 shows, in axial cross section, one form of separator in accordance with the present invention aid Fig. 2 shows a plan view of the cross-section of the separator illustrated in Fig. 1.

The separator illustrated generally comprises a cylindrical vessel 11 arranged with its central axis substantially vertical,said vessel 11 comprising a cylindrical wall 12 with a substantially flat lid 13 closing its upper regions and a downwardly and inwardly tapering wall 14 closing its lower regions.

Sle lid 13 includes an arcuate aperture 15 therethrough, adjacent to the cylindrical zall 12, and the aperture 15 is surrounded by an upstanding wall 15.

The lid 13 also includes a central opening 17, surrounded by an upstanding wall 18 which is brolcen at one side to open into a channel defined by a base 19 and upstanding side walls 20 and 21.

The lid 13 also presents a downwardly depending annular skirt or wall 22, concentric with the opening 17, and the diameter of the annular wall 22 is between half and three quarters of the diameter of tha cylindrical wall 12.

The lower regions of the wall 14 terminate at a central well 23, defined by a base 24 and cylindrical side wall 25, and the well 23 discharges via a conduit 26, which includes a valve 27 and a flow meter 28.

Contaminated liquid can be delivered direct to the vessel 11 by a conduit including a flow control valve but in the illustrated ernbodirnent contaminated liquid is supplied by a conduit 29 to- a rectangular header tank 30, defined by a base 31, upstanding side walls 32 and 33 and end walls, only one of which end wall 34 is illuserated in the draT7ing.A filter 35, defined in the illustrated example by a sheet of wire mes!l, is supported within the header tank 30 at a location spaced above the base 31, that end wall of header tangle 30 not illustrated in the drawing has a height substantially equal to the height of the side walls 32 and 33 but the end wall 34 has a height which terminates at, or slightly above, the plane of the filter 35.

The header tank 30 discharges to the vessel 11 via a conduit 36 which opens at its end remote from tank 30 through the side well 12 of vessel 11, at which point the conduit 36 discharges into a nozzle arrangement. The nozzle arrangement is defined by a wall 37, spaced frozen the cylindrical wall 12 by top and bottom walls 38 and 39 and one end wall 40 and opens to the interior of vessel 11 only via a vertical slot so that the liquid discharged through said vertical slot has a direction subs tent ially parallel to the cylindrical wall 12.

A conduit 41 OpC.lS at one end through the bottom 31 of header tank 30 and opens at its other end into the outlet conduit 26, between the well 23 and the valve 27, and conduit 41 includes a valve 42 adjacent tle header tanls 30.

The valves 27 and 42 are arranged to be opened and closed in response to sirlals from a control box 43 which receives signals from the flow Inter 20.

A tubular member 44, open at both ends, has radial vanes 45 extending from a core rod 45 located therein and the tubular element 44, vanes 45 and core rod 45 are suspended in tile upper regions of the cylindrical vessel 11 by the rod 46 which passes upwardly through a cap 47 resting on thn side-wall 18, the upper part of core rod 46 is threaded and a nut 48 on the threaded part of rod 46 rests on the plate 47 and allows for minor axial adjustments in height for the assembly comprising tubular element 44, core rod 46 and vanes 45.

The separator described above operates as follows: Contaminated liquid to be cleaned of heavy and light particulates is discharged from conduit 29 at a rate greater than that which can pass through the conduit 3s, solids contaminates too large to pass through the filter 35 are arrested by filter 35, the continuous flow fo;n conduit 29 rashes the arrested contaminates towards that end of filter 35 adjacent wall 34 and the said contaminates are carried over wall 34 by the excess liquid fro!n conduit 29. Thus the system provides for "self cleaning" of the filter 35.

By allozinj overflow liquid to discharge over the wall 34 a substantially constant head of liquid is maintained in header tank 30 and, thereby, the liquid supplied to conduit 36 for discharge into vessel 11 flows at a substantially constant rate through conduit 36 and through the vertical nozzle defined by the walls 12, 37, 38, 39 and 40 within the vessel 11.

t#en the vessel 11 is fully charged with liquid the continuous flow from the vertical nozzle into vessel 11 induces circulating flows within the vessel 11, the flows discharged from the vertical nozzle are directed substantially parallel to the cylindrical wall 12 and the circulation floes are thus generally inwardly towards the axis~of the vessel 11.

The 13.ninar flows induced in the liquid, by the first circulations adjacent wall 12, allow the light particulate contaminates to rise into the volume between side wall 12 and the downwardly depeno.ina annular wall 22. The wall 22 thereby constitutes a flow modifying render which prevents light particulate contaminates from florin into the outlet 17.The light particulate contaminates thus eventually rise to the undersurface of the lid 13 and are carried around by the circulatory flows between the wall 22 and wall 12 until said contaminates can rise through the arcuate aperture 15 and up@ardly through the volume of liquid contained by upstanding shall 16, for eventual discharge via a conduit 49.

The circulation of the liquid adjacent the wall 12 further allows the heavy particulate contaminates to fall towards the wall 14 and the c#ontinuous circulation of the liquid in vessel 11 carries the heavy contaminates down the wall 14 into the well 23 from which said heavy contaminates are removed via conduit 26.

With the fall of heavy particulate contaminates towards the wall 14, and the lightweights rising outwardly of the annular wall 22, the liquid within the volume defined by annular wall 22, and the liquid immediately therebeneath, is relatively clear of particulate contaminates and leaves the vessel via the central opening 17, into the volume defined by the arit##lar wall 13 and is discharged therefrom, via the duct comprising base 19 and side-walls 20 and 21.

It has been found in practise that a separator, operating as described above and without the cylinder 44 vanes 45 and rod 46, can act relatively effectively without any internal flow modifying elsslnents other than the skirt or wall 22 and is so efficient that in separating the particulate contaminates from the liquid only some 2 to 570 of the liquid is required to leave the system via conduit 44 (to carry away the light particulate contaminates), only some 10-30% is required to leave the vessel via conduit 26 (to carry away the heavy particulates and the remainder of the liquid is discharged from the vessel 11 as clear liquid, substantially free from particulate contaminates.

2,y flaintaining a substantially uniform and constant supply of particulate contaminated liquid to the vessel and maintaining uniform and constant rates of flow from the light particulates outlet 15, the heavy particulates outlet 23 and the clean liquid outlet 17 relatively uniform and constant circulations flows are established within the vessel 11. further, by controlling the rates of flow from the li'nts outlet and the heavies outlet, the rate of flow through the de-contaninated outlet can be adjusted to obtain an acceptable degree of de-contamination.

With the above arrangement the greater part of the liquid leaves the vessel 11 via the outlet 17, and this take-off induces an upwardly flowing vortex in the upper regions of the vessel 11. This vortex wea':ens with depth but in the event that the rate of flow through the all 23 ard conduit 26 is reduced, as by a blockage in well 23 and/or conduit 26, the vortex strengthens and can extend downwardly into the heavily contaminated liquid in the lower regions of vessel 11 and entrain heavy particulate contaminates and carry said contaminates upwardly to the outlet 17, thus contaminating the liquid passing through outlet 17.

One method proposed by the present invention for overcoming this problem is to include within the vessel 11 a tubular flow modifying nember comprising the suspended tubular member 44 with the radial vanes 45 on core -tso and which arrangement has been found to be most effective for breaking åos the upvsardly rising circulating flows.

with such aa arrangem.#nt, suspended in the upper regions of the cylinder 11, and even with a prolonged blockage of the well 23 or conduit 26, upwardly rising circulating flows carrying heavy particulate contarii.#nates can be completely avoided.

As liquids of different compositions behave differently the height of the tubular member 44 is adjustable so as to be located at the most effective position for dealing with a specific liquid and whilst in the illustrated example the tubular member 44 is Bhown as suspended by the core rod 46 and vanes 45 said member 44 may be independently supported and the core rod 46 and vanes 45 may be independently supported and axially adjustable within the tubular member 44.

Conduit 41, the valves 27 and 42, the flow meter 28 and-the control unit 43 are provided to automatically clear blockages from the heavqr particulate eontallinates outlet.

The flow meter 25 continuously monitors the rate of flow of liquid and contaminates through the conduit 26 and sends a signal indicative of the flow rate to the control unit 43. #hj.lst a good, continuous flow rate signal is received from flow meter 28 the control 43 holds tlle valve 42 closed and the valve 27 open so that heavily contaminated liquid is continuously drawn off from the well 23 and discharged via conduit 26.

In the event of a blockage in the well 23, or the section of conduit 26 between well 23 and valve 27 (the most likely location for stoppages), the flow along conduit 26 will be reduced and this reduced flow will be monitored by the flow meter 28 and signalled to control device 43. Control device 43 will then close valve 27 and open valve 42 so that liquid can flow from the header tank 30 via conduit 41 into the conduit 26 between valve 27 and well 23. With valve 27 closed the flow of liquid from conduit 41 will be in the reverse direction to normal flow within conduit 26 and will flow into the well 23 and uzardly into the vessel 11, thus clearing any blockages that may exist therein.

The control unit 43 will include a timer which, after allowing for closure of valve 27 and opening of valve 42 for a predetermined time period, will then close valve 42 and re-open valve 27 so that evacuation of heavily contaminated liquids along conduit 26 is rei established.If at tnis point the flow meter 28 records normal flow along conduit 26 tlle system will continue to operate as normal but in the event that the flow meter 23 does not send to the control unit 43 the signal indicative of normal flow the control unit 43 can again actuate valves 42 and 27 to direct liquid from header tank 30 into conduit 26 and through well 23 into the lower regions of chamber 11 and, conveniently, the said unit 43 can actuate an alarm to draw attention to the blockage situation.

Most preferably the timer is arranged to allow only short pulses of liquid via the conduit 41 so that the circulating flows within the vessel 11 are not disrupted.

As an alternative to the conduit 41 supplying liquid from the tank 3 said conduit Itl may be connected to an alternative liquid supply.

tNlilst the above embodiment has been described with respect to the removal of solids contaminates from a liquid it will be appreciated that the separator can effectively separate emulsions when the liquids formino the continuous and discontinuous phases are of different specific gravities.

whilst the above embodiment has been described by way of example with reference to a specific embodiment the invention is not restricted thereto and many modifications and variations will be apparent to persons skilled in the art.

Claims (1)

1. A separator, of the type defined, comprising a vessel for containing fluid to be cleaned of particulate contaminates, means for introJucing contaminated fluid to said vessel at such rate and with such direction as to induce flows, circulating about a substantially vertical axis, in the fluid in the vessel, a first outlet tlwoussz which particulate contaminates can.:be removed from the vessel and a second outlet through which substantially de-contaminated fluid can be removed from the vessel, characterised in that such flow modifying members or elements as are provided to affect the movement of the fluid within the vessel are located substantially in the upper regions of tle vessel.

2. A separator as claimed in claim 1 characterised in that all such flow modifying members or elements as are provided to affect the movement of the fluid within the vessel are supported by the roof of the vessel.

3. A separator as claimed in claim 1 or 2 characterised in that said first outlet is in the lower regions of the vessel and allows heavy particulate contaminates to be discharged from the vessel an!l sajI first and second outlets are concentric with the central axis of the vessel.

4. A separator as claimed in claim 1, 2 or 3 characterised in that a third outlet is provided in the upper regions of the vessel, said third outlet is spaced from the central axis of the vessel and said third outlet allows light particulate contaminates to be discharged from the vessel.

-5. A separator as claimed in claim claim 1, 2, 3 or 4 characterised by a flow modifying element comprising an annular shirt depending r#ot#wardly from the roof of the vessel, concentric with the axis of the vessel and having an internal diameter greater than the diameter of said second outlet.

6. A separator as claimed in claim 5, when dependent upon claim 4, characterised in that said third outlet opens through the roof of the vessel between said annular skirt and the side wall of the vessel.

7. A separator as claimed in any preceding claim characterised in that a tubular flow modifying member, having an internal diameter substantially equal to the diameter of said second outlet, depends downwardly into the upper regions of the vessel concentric with the axis of the vessel.

S. A separator as claimed in claim 7 characterised in that means are provided for axially adjusting the position of said tubular flow modifying member within the vessel.

A separator as claimed in claim 7 or 8 characterised in that a circulsting flow suppression member is located in said tubular flow modifying member, said circulating flow suppression uember comprising a cora element, concentric with the axis of said tubular flow modifying member, with radial vanes extending there fro#.

ln. A separator as claimed in claim 9 in which the peripheries of the said vanes extend to the bore of said tubular flow modifying member.

11. A separator as claimed in claim 9 in which the peripheries of the vanes have a clearance fit in the bore of said tubular flow modifying member and means are provided for axially adjusting the position of said circulating flow modifying meir2r relative to said tubular flow modifying member.

12. A separator as claimed in any preceding claim characterised by a nozzle through which the contaminated fluid to be cleaned is released into the vessel, said nozzle being located in or by a side wall of the vessel substantially parallel to .e central axis of the vessel and arranged to direct fluid released therefrom generally parallel to the adjacent side wall and substantially at right angles to the axis of the vessel.

13 A separator as claimed in any preceding claim characterised in that ducting, for conveying heavy particulate contaninates from the vessel, include valve means and a fluid supply !ry -dliel a reverse flow of fluid can be released into sail ducting to clear heavy particulate contaminate blockages therefrom.

14. A separator, substantially as hereinbefore described, with reference to and as illustrated in Figs. 1 and 2 of the accompanying drawings.