GB2156709A - Improvements in or relating to separation - Google Patents

Abstract

A separator (1) includes a horizontal main vortex chamber (4) and at least one secondary vortex chamber (14, 16) intersecting and opening into the main chamber (4), the or each secondary chamber (14, 16) being of curvilinear form. <IMAGE>

Description

SPECIFICATION Improvements in or relating to separation This invention concerns improvements in or relating to separation, and has reference to the separation of an element from a combination of elements such for example as gas/solid, liquid/solid or iiquid/liquid mixtures according to size and/or density.

Separation in the context of the invention includes collection and classification. Thus, for example, in the case of gas/solid combinations, the solid, usually particulate, element may be collected substantially completely from the carrier gas, or a specific size fraction or cut of the solid element may be removed from the carrier gas, the solid element thereby being classified.

In our co-pending British Patent Application 82/30720 (2 108 there is diclosed a cyclone separator which operates in a vertical position and incorporates a secondary vortex chamber opening into the main vortex chamber, in use the element to be separated being sheared off into the secondary chamber from the vertical flow in the main chamber. The element so sheared off is captured in the secondary vortex, which is driven by the main vortex, and precipitates out in the secondary vortex chamber, there being no net flow of the carrier into or out of the secondary vortex chamber. Both the main vortex chamber and the secondary vortex chamber of our earlier application are part circular in shape and overlap one another in the manner of intersecting circles.

We have now found that the separator may be orientated other than in the vertical mode, but yielding the same beneficial results.

It is an object of the invention therefore to provide an improved separator.

According to the invention there is provided a separator for separating an element from a fluid carrier, the separator including a generally circular section main vortex chamber adapted in use to be horizontally orientated, an inlet and an outlet for the main vortex chamber, and at least one secondary vortex chamber intersecting and opening into the main vortex chamber to provide communication therebetween, the secondary vortex chamber being of curvilinear form a part circular section thereof registering with the main vortex chamber and leading to a linear section.

Preferably, in use, there is no net flow of the fluid carrier into or out of the secondary vortex chamber.

Conveniently, more than one secondary vortex chamber may be provided, each such chamber being situated at a different location along the length of the main vortex chamber which may be of cylindrical form.

The inlet may be tangential to the main vortex chamber which may be provided with a vortex finder tube. The main vortex chamber may be of stepped cylindrical form having an inlet section to which the inlet is connected, the inlet section being of greater diameter than the remainder of the body which protrudes into the inlet section in such a manner as to give a scroll effect.

A vortex finder tube penetrates one end of the main vortex chamber and conveniently constitutes the outlet from that chamber. A secondary vortex chamber may advantageously be associated with the tube in a similar intersecting fashion and opening into the tube externally of the main vortex chamber.

The other end of the main vortex chamber may be closed by a plate. Alternatively, the other end may be apertured and may lead to a further separation chamber disposed centrally of the said end. A relatively short tube may connect the further separation chamber with the main vortex chamber and may be provided with a radiussed entry neck adjacent the aperture in the end of the main vortex chamber.

The or each secondary vortex chamber comprises a part circular, preferably semi-circular, section relieved along its circumferential boundary to register with an opening in the wall of the main vortex chamber. A linear section is contiguous with the part circular section and is closed. Conveniently, the linear section may be removable from the part circular section for discharge of the separated element.

The openings in the wall of the main vortex chamber may be offset circumferentially from one another. For example, one or more openings may be provided along the lower boundary wall of the main vortex chamber, other openings being offset therefrcm by 90 to be located in the side boundary wall of the main vortex chamber.

By way of example only various embodiments of the separator according to the present invention are described below with reference to the accompanying drawings in which: Figure 1 is a vertical longitudinal section on the line I-I of Figure 2 showing a first embodiment of the separator; Figure 2 is a section on the line Il-Il of Figure 1; Figure 3 is a section on the line Ill-Ill of Figure 1; Figure 4 is a section on the line IV-IV of Figure 1; Figure 5 is a vertical longitudinal section through a second embodiment; Figure 6 is a diagrammatic illustration of a first mode of operation of a secondary vortex chamber opening into the side of a main vortex chamber of the separator; and Figure 7 is a diagrammatic illustration of a second mode of operation.

Referring first to Figures 1 to 4, a separator 1 includes a horizontal body 2 defining a main vortex chamber 4 of stepped cylindrical form with a scrolled inlet section 6 of greater diameter than the main section 8. A tangential inlet 7 feeds the section 6 and is supplied by a pipe 9. The main section 8 protrudes part way into the inlet section 6, the axes of the respective sections being parallel and offset from one another to define the scroll effect as can more readily be seen from Figure 2.

The section 8 also provides a weir for incoming flow for stabilising in use the vortex generated within the main chamber prior to its entry into section 8. A vortex finder tube 10 extends through an end of the inlet section 6 and part way into section 8 which is closed at its end remote from the inlet section 6, the tube 10 constituting an outlet 12 from the main vortex chamber 4.

A first secondary vortex chamber 14 is associated with the inlet section 6 and second and third secondary vortex chambers 16, 18 all associated with the section 8. A fourth secondary vortex chamber 20 is associated with the tube 10 externally of the chamber 4.

The chambers 14, 16 and 20 are each of curvilinear form with a semi-cylindrical part 22 registering with openings 24, 26, 28 respectively in the Sections 6, 8 and tube 10 respectively.

The semi-cylindrical part 22 of each chamber 14, 16, 20 is relieved along its circumference to intersect with the respective section opening 24, 26, 28 to provide flow communication. A linear part 30 is contanguous with each part 22 and depends vertically therefrom, the part 30 being closed but detachable from part 22.

The chamber 18 is also of curvilinear form and has a part cylindrical portion 32 registering at its side margin with an opening 34 in section 8, and leading to a closed linear portion 36 detachable from part 32.

In operation, a fluid carrier, for example gas having particulate matter entrained therein is introduced via the pipe 9 and inlet 7 into the section 6 wherein a primary vortex is generated and stabilised by the protrusion of section 8 therein. As can be see from Figure 2, the flow of the gas/solid combination is anticlockwise and the scroll effect coupled with the vortex action concentrates at least some of the particles in a boundary layer close to the wall of the section 8. Once the main vortex is generated, secondary vortices are also generated in the chambers 14, 16, 18 and driven by the main vortex.

Upon the flow encountering the chamber 14, the boundary layer of particles is shaved off and captured by the secondary vortex which as viewed in Figure 2 rotates clockwise.

The particles so captured are precipitated in the linear part 30.

The main vortex stabilised in section 6 spills over the weir constituted by the part of section 8 extending into section 6, and continues its path around the tube 10 in section 8, again particulate matter being concentrated in a boundary layer adjacent the wall of the section. Upon encountering the chambers 16, 18, the boundary layer of particles is sheared off into the chambers and is captured by the secondary vortices, the particles being precipitated into the part 30 and portion 36 respectively. The main vortex extending down to the closed end turns back on itself and flows generally axially along part 6 and into the tube 10. Any remaining particles not removed within the main vortex chamber are concentrated in a boundary layer within the tube 10 and are shaved off into the chamber 20 in which a secondary vortex is generated and driven by the main vortex.Particles so captured precipitate in part 30.

All the secondary vortex chambers are closed and thus no net gas flow occurs across the boundary between the main and secondary chambers. The linear parts 30 and portion 36 can be removed as and when necessary for the discharge of separated particles.

The mode of operation described above merely exemplifies the application of the separator. In particulaar, the separator is used in this instance as a collector to remove all the particulate element in the gas/solid combination. It could equally be used for removing particles from a liquid or for removing one liquid element from a combination of liquid elements according to density. Furthermore, the separator could be employed as an integral part of a cyclone combustor to remove contaminants from combustion gases prior to their discharge. However, the separator may also be used in a classifying mode wherein specific size or density cuts or fractions are required to be removed from the carrier fluid.

Referring now to Figure 5, there is shown a variation on the embodiment of Figures 1 to 4 and like numerals of reference have accordingly been used. In this second embodiment, an expansion chamber is provided at the end of the main chamber 4 remote from the inlet section 6. That end of the chamber 4 is provided with a central aperture 40 communicating with a short length of tube 42 having a radiussed neck 44 contiguous with the aperture. The tube 42 leads to a cylindrical pot 46 orientated vertically with respect to the horizontal chamber 4. In operation, the separator operates in essentially the same manner as before, but the main vortex extends through the tube 42 and into pot 46 where there is an expansion effect resulting in precipitation of particles entrained in this instance by a carrier gas. The particles gravitate to the base of the pot 46 which is closed. Particles may be removed from the pot 46 as and when necessary. With reference to Figure 6, the operational mode of chamber 18 is shown and as can be seen the main vortical flow is anticlockwise and the secondary vortex rotates clockwise. In this instance the particles, in the case of a gas/solids combination, are carried upwardly into the part cylindrical portion 32 or the chamber 18 and then fall out of the vortex close to the wall of linear portion 36 remote from the main chamber.

Referring to Figure 7, the mode of operation is reverse to that described in relation to Figure 6 in that the main vortical flow is clockwise. Thus in the case of a gas/solids combination the particulates tend to precipitate out close to the wall of linear portion 36 of the secondary chamber 18 immediately adjacent to the main chamber.

The manner of the entry into the secondary chamber of the element removed from the carrier fluid can be varied by appropriate location of this secondary chamber in relation to the rotation of the vortices.

As indicated previously, the separator of the present invention can be employed for separating an element from a combination of elements, for example gas/solids, liquid/solids or liquid/liquid mixtures and can be operated for the purposes of collection or classification.

Claims (19)

1. A separator for separating an element from a fluid carrier, the separator including a generally circular section main vortex chamber adapted in use to be horizontally orientated, an inlet and an outlet for the main vortex chamber, and at least one secondary vortex chamber intersecting and opening into the main vortex to provide communication therebetween, the secondary vortex chamber being of curvilinear form, a part circular section thereof registering with the main vortex chamber and leading to a linear section.

2. A separator according to claim 1 in which the secondary vortex chamber is closed Whereby in use no net gas flow occurs across the boundary between the main and secondary vortex chambers.

3. A separator according to claim 1 or 2 in which two or more secondary vortex chambers are provided, each chamber being situated at a different location along the length of the main vortex chamber.

4. A separator according to any one of the preceding claims in which the main vortex chamber is of cylindrical form.

5. A separator according to claim 4 in which the main chamber is of stepped cylindrical form having an inlet section to which the inlet is connected, the inlet section being of greater diameter than the remainder of the body which projects into the inlet section in such manner as to give a scroll effect.

6. A separator according to any one of the preceding claims in which a vortex finder tube extends through one end of the main vortex chamber and constitutes the outlet from the main vortex chamber.

7. A separator according to claim 6 in which a part of the vortex finder tube external to the main chamber is provided with a secondary vortex chamber.

8. A separator according to any one of the preceding claims in which the end of the main vortex chamber remote from the outlet is closed.

9. A separator according to any one of the claims 1 to 7 in which the end of the main vortex chamber remote from the outlet is provided with an aperture communicating with a separation chamber.

10. A separator according to claim 9 in which the separation chamber is connected to the aperture by a tube.

11. A separator according to claim 10 in which the tube is provided with radiussed neck adjacent the aperture.

12. A separator according to any one of the preceding claims in which the or each secondary vortex chamber includes a part circular section relieved along its circumferential boundary to register with an opening in the wall of the main vortex chamber.

13. A separator according to claim 12 in which the or each secondary vortex chamber includes a linear section contiguous with the part circular section and is closed.

14. A separator according to claim 13 in which the linear section of the or each secondary vortex chamber is removable from the part circular section.

15. A separator according to claim 12 in which two or more openings are provided, the openings being offset one from the other or others circumferentially of the main vortex chamber.

16. A separator according to claim 15 in which at least one of the said openings is disposed on the circumference on a horizontal diametral line.

17. A separator according to claim 16 in which the at least one said opening is disposed on the circumference at one or other of the diametral extremities.

18. A separator according to claim 15 in which at least one of said openings is disposed on the circumference at a diametral extremity thereof.

19. A separator substantially as hereinbefore described with reference to Figures 1 to 4, 5, 6 or 7 of the accompanying drawings.