WO2020222240A1

WO2020222240A1 - Cyclonic separator and method of use

Info

Publication number: WO2020222240A1
Application number: PCT/IL2020/050485
Authority: WO
Inventors: Meir Amit
Original assignee: Meir Amit
Priority date: 2019-05-01
Filing date: 2020-04-30
Publication date: 2020-11-05
Also published as: IL266394B; IL266394A

Abstract

A centrifugal separator (CS) for separating suspending particles from a fluid comprises an external circular body, a flow diffuser disposed at the upper part of the CS and concentric with its central longitudinal line, an internal space separator disposed inside the external body and coaxially with it with respect to a central longitudinal line of the external body, the internal space separator defines a fluid flow circulation space between it and the external circular body underneath the flow diffuser and an inlet tube to provide pressurized fluid to the flow diffuser via its inlet hole.

Description

CYCLONIC SEPARATOR AND METHOD OF USE

BACKGROUND OF THE INVENTION

[001] Cyclonic separators are well known for using to separate particles dispersed or suspended in a fluid, based in differences in specific weight. For example, sand/dust particles suspended in water or in air/gas may be separated from the water/air/gas using cyclonic separator because the specific weight of sand or dust is higher than that of water/fluid or the specific weight of dust is typically higher than that of air/gas. Reference is made to Figs. 1A and IB, which are schematic illustration of CS 100 as is known in the art, in side view and in top view. CS 100 comprises CS tank 102 that is typically installed for operation with its central longitudinal axis vertical to the horizon. CS tank 102 typically comprises an upper cylindrical part 102A and a lower conical part 102B connected at its upper wider opening to the upper part 102A. the lower narrower opening of conical part 102B ends with a pathway to disposal tank 108. Flow of fluid may enter CS 100 through entry pipe 104 that typically penetrates the face of cylindrical part 102A tangentially, as is shown in Fig. IB. The tangential connection of entry pipe 104 is done in order to exert circular/tangential flow of the entering fluid around the inner face of tank 102. The basic operation principle of the cyclonic separator (CS) is forcing a flow of fluid to flow in a circular motion path, as depicted by the“internal flow” dashed line, in a circular speed that exerts strong enough centrifugal force on the sand particles that forces them towards the inner face of the CS body, where the particles are allowed to sink down in the CS tank due to gravitational force and the be collected for example in disposal tank 108 located typically at the bottom of the CS body.

[002] In order to speed-up the circular motion of the fluid the cylindrical part 102A of tank 102 transfers the circular motion to the conical part 102B, where the continuously decreasing radius of the conical part forces the circular speed to increase, thereby increasing the centrifugal forces.

[003] The flow of fluid gets gradually cleaner from suspending sand particles. The sand particles gradually sink into disposal tank 108 due to gravitational force. Fluid which was released from sand particles is forced out of CS 100 via the only open exit of exit pipe 106, where it may be connected back to a fluid line. [004] CS known in the art, such as CS 100, suffer of several drawbacks. First, only part of the fluid inside tank 102 is exposed to the effect of the centrifugal force, mainly the portion of the circulating flow that is close to the inner face of tank 102, and especially the part of flow that is close to the inner face of the conical part 102B of tank 102. As a result, the efficiency of t separation is not high enough.

[005] Second, due to the speeding-up of the rotational speed at the conical part 102B of tank 102 the centrifugal force that develops may, at certain speeds, be strong enough to cause, by its fraction vector that is tangential to the inner face of the conical part 102B, at least some of the sand particles to be pushed up the conical face, thereby preventing these particles from flowing into disposal tank 108. Reference is made now also to Fig. 1C, which is a schematic forces diagram of forces developing next to internal face of the conical part 102B, as is known in the art. Centrifugal force that acts on a sand particle is marked 130 and it is directed outwardly from the center of tank 102 and in the plane of rotation of the fluid. Force 130 may be separated to fraction 130A that is perpendicular to the inner face of conical part 102B and to fraction 130B that is parallel to the inner face of conical part 102B. fraction force 130B may further be separated to vertical fraction 130B 1 and to a completing horizontal fraction (not shown in order to not obscure the drawing. When the rotational speed is high enough, so that fraction 130B1 of fraction 130B of the centrifugal force, equals to or higher than the gravitational force at that point, a sand particle there will not be able to sink down, and may even be drifted up with the flow of fluid, until the balance changes back and the gravitational force becomes higher. As is well known, the circular motion of the fluid, that was initiated by the energy of the entering flow and the tangential entry into tank 102 slows down quite rapidly due to the viscosity of the fluid. Moreover, in the center of tank 102 internal turbulences further reduce the energy of the rotational flow. The change of the tank’s cross section shape from cylinder to cone is meant primarily to overcome the problem of the reduction of rotational speed of the fluid.

[006] Further, the effect of the fraction 130A that acts perpendicular to the inner face of tank 102 with the sand particles suspending in the fluid, exerts grinding effect on the inner face of tank 102, like toe operation of a sandpaper. This effect grows as the circular speed grows. The known result is expedited wear of the conical part of tank 102. In some known CSs the conical part is covered internally with a protective foil that may easily be replaced when needed. While such solution solves some aspects of the problem, it requires lengthy down-time and may cause grinded particles of the inner protective foil and thereby contamination of the fluid. [007] Last but not least, due to the need to allow flow of the incoming fluid down inside the tank, on the one hand and the need to place disposal tank 108 at the bottom-most location of the CS on the other hand, the entry tube and the exit tube are located high above the bottom of the CS 100. Since fluid pipes, such as water pipes, are usually installed underground or, at least, just up of and next to the face of earth, when a separator known in the art is used, special bends will have to be provided to the incoming and outgoing pipes to enable installation of the separator in an existing pipeline.

[008] There is a need for a fluid centrifugal separator that enables efficient rotational flow of the entire amount of fluid in a CS tank, that provides for fast enough flow speed in it to ensure that most of the particles are separated from the fluid prior to its flow out of the CS, for a wide range of incoming flow speeds or capacities. Further, there is a need for a design of the CS that will enable simple installation into a fluid line, with minimal required changes to the line.

SUMMARY OF THE INVENTION

[009] A centrifugal separator (CS) for separating suspending particles from a fluid is presented comprising an external circular body having a top cover and a bottom cover and a central longitudinal line, a flow diffuser disposed at the upper part of the CS and concentric with the central longitudinal line, an internal space separator disposed inside the external body and coaxially with it with respect to a central longitudinal line of the external body, the internal space separator defines a fluid flow circulation space between it and the external circular body underneath the flow diffuser and an inlet tube to provide pressurized fluid to the flow diffuser via its inlet hole. In some embodiments the flow diffuser comprising plurality of helical partitions, a top disc plate and a bottom disc plate wherein the plurality of helical partitions are disposed between the top and the bottom plates, extending from an inlet hole made in the bottom plate to the circumference of the bottom plate, circularly evenly distanced from each other, thereby forming plurality of small helical flow diverting paths between each pair of adjacent partitions, the top disc plate and the bottom disc plate.

[0010] In some embodiments the centrifugal separator further comprising an outlet tube to provide exit path for the fluid, the outlet tube is disposed concentric with the central longitudinal line, internal to the internal space separator and external to the inlet tube thereby leaving flow path between the outlet tube and the inlet tube. [0011] In some embodiments the centrifugal separator further comprising a disposal tank connectable at the bottom of the external body and with free passage for disposable particles from the external tank to the disposal tank.

[0012] In some embodiments the centrifugal separator further comprising a helical flow directing structure disposed in the space between the external body and the internal space separator, adapted to direct flow leaving the flow diffuser circularly down inside the space between the external body and the internal space separator.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings in which:

[0014] Figs. 1A and IB are schematic illustration of a centrifugal separator as is known in the art, in side view and in top view respectively;

[0015] Fig. 1C is a schematic forces diagram of forces developing next to internal face of the conical part of centrifugal separator of Figs. 1A and IB, as is known in the art;

[0016] Figs. 2A and 2B are schematic side view of a cyclonic separator and a side and top view of its diffuser, according to some embodiments of the present invention;

[0017] Fig. 3 depicts a schematic illustration of a centrifugal separator, according to embodiments of the present invention;

[0018] Fig. 4 is a schematic partial illustration of centrifugal separator, presenting details of flow control means, built and operative according to embodiments of the present invention; and

[0019] Figs. 5A and 5B are schematic illustrations depicting centrifugal separators according to embodiments of the present invention.

[0020] In some embodiments a centrifugal separator (CS) for separating suspending particles from a fluid is disclosed comprising an external circular body having a top cover and a bottom cover and a central longitudinal line, an internal space separator disposed inside the external body and coaxially with it with respect to a central longitudinal line of the external body, the internal space separator defines a fluid flow circulation space between it and the external circular body and an inlet tube to provide pressurized fluid to the flow diffuser via its inlet hole.

[0021] It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0022] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the present invention.

[0023] In the description of embodiments of the present invention where relative directions such“up, upper, low, lower, above, below”, etc. are used, they should be understood with respect to the below described embodiments of centrifugal separator when it is installed ready for work with its central longitudinal axis is vertical, its top cap faces up and its bottom facing substantially down with respect to the direction of gravity. The term“fluid” as used throughout the specification below is meant to describe any type of material that is capable of flow, such as liquid, gas, etc., unless otherwise specifically mentioned. The basic principle of operation of embodiments of the centrifugal separator of the invention rely on the difference of centrifugal forces exerted on materials with different specific weight that are circulated in a common angular speed.

[0024] Reference is made to Figs. 2A and 2B, which are schematic side view of a cyclonic separator (CS) 2000, and a side and top view of diffuser 2300, respectively, according to some embodiments of the present invention. CS 2000 comprises a circular external body 2100 that is closed at one end by a cap 2102 and at the other end by a bottom 2104. Inside external body 2100 an internal space separator that is a tube-like circular cylinder 2110 is installed, sharing a common longitudinal axis with body 2100. Cylinder 2110 defines a ring-like cylindrical space 2106 between its external face and the internal face of external body 2100. Cylinder 2110 extends from below diffuser 2300 (discussed below in detail) and downward till next to bottom 2104.

[0025] Along the central and common longitudinal axis of external body 2100 inlet tube 2012 enters through bottom 2104 and symmetrically extends up toward diffuser 2300. Inlet tube 2012 is inserted through outlet tube 2022 that has a larger diameter than that of inlet tube 2012. The space defined inside inlet tube 2012 is usable for providing pressurized fluid into CS 2000. The space defined between inlet tube 2012 and outlet tube 2022 is usable for allowing flow of fluid out of CS 2000. Outlet tube 2022 extends from close below, and apart from the bottom of diffuser 2300 down and out of external body 2100 through its bottom 2014.

[0026] Inlet tube 2012 is connected at its upper end to fluid entrance 2312 of diffuser 2300.

[0027] Diffuser 2300 may comprise top circular plate 2320 and bottom circular plate 2310 are disposed parallel to and spaced apart from each other. Bottom plate has an inlet hole 2312 in its center to allow flow of fluid through it into the diffuser. Between the upper plate 2320 and the bottom plate 2310 a plurality of helical partitions 2330 are disposed extending from an internal imaginary circle 2314 outwardly to the external circumference of the plates. The helical partitions 2330 are disposed in a circular symmetry around, forming small helical flow diverting paths 2332 between each pair of adjacent partitions, the top disc plate 2320 and the bottom disc plate 2310.

[0028] As will be explained herein after, one aspect of this embodiment is the entry of the inlet stream into the body of the separator is done from the middle of that body and the flow is directed outwardly from the center to the inner circumference of the body of the separator - as opposed to prior art separator described above. Fluid that is forced by high pressure through inlet hole 2312 is substantially uniformly jetted through the helical flow divertors around the center of diffuser 2300 as depicted by flow line 2340. As seen in Fig. 2B, the jet of fluid that is forced out of diffuser 2300 meets the inner face of external body 2100 at a tangential angle 2342, that has a rather low value, e.g. between 20 and 40 degrees. The multiplicity of flow divertors and the low angle of impingement of the fluid leaving the diffuser ensure fast and energetic circular flow around the inner face of external body 2100 at the top part of CS 2000, marked 2000A.

[0029] The circulating fluid that left part 2000A next to the diffuser, keeps circulating while descending towards the bottom of CS 2000 due to pressure differences between the input and output of the separator and assisted by gravity force. A helical flow directing structure (HFDS) 2200 is disposed in space 2106 between external body 2100 and cylinder 2110. The direction of the spaces between adjacent helical rounds of the helix of HFDS 2200 matches for continuing the direction of circular flow of fluid leaving diffuser 2300 and directing it between the helical rounds to support and maintain the circular motion in space 2106, thereby forcing substantially the entire fluid inside space 2106 to circulate while going down within section 2000B of CS 2000, as depicted by arrows 2101. As a result an efficient centrifugal effect is exerted on the entire amount of fluid leaving diffuser 2300, without central turbulences and with virtually no loses of circular velocity due to the viscosity of the fluid.

[0030] Particles that are forced to the inner face of the external body 2100 are moved down to the bottom 2104 of CS 2000 and gradually dragged by the flow to the disposal outlet 2402 an then into disposal tank 2400.

[0031] Circulating flow that reached bottom 2104 finds its way up into the space 2108 defined between the inner face of cylinder 2110 and outlet tube 2022, as depicted by arrows 2100A. When the fluid reaches the top of space 2108 it enters the upper end of outlet tube 2022 and changes direction again downward between outlet tube 2022 and inlet tube 2012, as depicted by arrows 2100B. the rapid change of flow direction depicted by arrows 2100A may assist in separating last remaining particles in the fluid, due to the centrifugal force acting there. Fluid leaving through outlet tube 2022 is considered fluid-after-particles-separation (FAPS) and is considered nearly clean from particles.

[0032] In some embodiments contaminated fluid may be provided to CS 2000 via input tube 2010 that provides line contaminated fluid flow 2010A. in some additional embodiments FAPS flow may be directed from outlet tube 2022 to out tube 2020 to provide FAPS flow 2020A. input tube 2010 and out tube 2020 may be disposed along a common central line 2002, thereby allowing easy and fast installation into an existing pipeline, even if the existing pipeline is installed near the earth.

[0033] Disposal tank 2400 may be removably connected as is known in the art (not shown) to enable removal of accumulating particles in it. In other embodiments disposal tank may be equipped with mechanical or electro-mechanical, or hydro-mechanical means that are adapted to autonomously remove accumulated particles from disposal tank 2400, as is known in the art. [0034] In some embodiments the bottom 2104 of external body 2100 may be inclined with its lower end next to disposal outlet 2402. The inclination of bottom 2104 may assist in preventing residual particles that may still be suspending in the fluid next to the bottom from continuing further withy the flow of the fluid, due the change of the vertical direction of the circulating flow from down to up next to disposal outlet 2402.

[0035] In some embodiments a centrifugal separator may comprise an external body that has circular shape other than cylinder, as depicted in Fig. 2 A. For example, the external body may have a conical shape where the narrow cross section is attached next to the diffuser section and the wide cross section of the cone is attached to the bottom. Reference is made to Fig. 3, depicting schematic illustration of CS 3000, according to embodiments of the present invention. CS 3000 comprise main external body 3100, diffuser 3300 disposed on top of external body 3100, inlet tube 3010, outlet tube 3020 and disposal tank 3400. Most of the elements and mode of operation discussed with respect to CS 2000 are applicable with respect to CS 3000 with certain required changes. The external body 3100 has a circular shape of a cone with its narrow end directed up and connected to the diffuser 3300 section and its wide side is at the bottom. The internal space separator 3110 may have a circular cylinder shape or cone shape (as illustrated in Fig. 3), as may meet the performance requirements. The cone-like design of external body 3100 is made to assist, for certain mixtures of fluid with first specific weight and given viscosity and particles with a second specific weight and given average particles size, in allowing the particles that were separated from the fluid during the circulating motion down from the diffuser section to remain on the bottom or close to it and not be carried away by the circulating fluid. This is enabled due to the gradual reduction of the circulation speed of the fluid as the radius of the conical external body 3100 grows.

[0036] In some embodiments the flow of fluid through the centrifugal separator may be regulated. Reference is made to Fig. 4, which is a schematic partial illustration of centrifugal separator 4000, built and operative according to embodiments of the present invention. Centrifugal separator (CS) 4000 may be built and operative similar to CS 2000, with certain changes that are described herein below. Accordingly, the description of like elements of Fig. 2 is applicable also here. The entry point 4012A of fluid from inlet tube 4012 to diffuser 4300 may be coverable or plugged by a valve or a flow regulator 4350. Valve 4350 may comprise valve plug 4352 that is adapted to fully and tightly cover and block fluid exit 4012A or open this exit to a controllable extent, thereby controlling the capacity of fluid flow at a given fluid pressure. The extent to which opening 4353 is opened is determined by the movement of valve plug 4352. The opening may be determined by the valve operator unit 4354. Valve operator unit 4354 may be any type of valve operator known in the art, such as manual valve control, self-adjusting with local hydraulic feedback, remotely controlled, and the like.

[0037] It should be readily understood to those skilled in the art that effective and novel centrifugal separation may be achieved, according to embodiments of the present invention, by employing merely only some of the features of the centrifugal separators described above. For example, with regard to centrifugal separator 5100 of Fig. 5A to which reference is now made, diffuser 5150, similar to diffuser 2300 of Fig.2, may be placed at the top of a prior art centrifugal separator body, such as separator 100 of Fig. 1, thereby highly improving its separation efficiency by inducing higher centrifugal forces on the incoming fluid. Similarly, with regard to centrifugal separator 5200 of Fig.5B to which reference is now made, a helical flow directing structure 5250, similar to helical flow directing structure (HFDS) 2200 of Fig. 2A, may be placed within internal cylinder, such as cylinder 2110 of Fig. 2, or inside a prior art centrifugal separator, such as separator 100 of Fig. 1, thereby highly improving its efficiency. Hence, it should be understood that centrifugal separators of embodiments of the present invention may comprise even only one element from the novel elements of centrifugal separator 2000 of Fig. 2. For instance, according to one embodiment a centrifugal separator may comprise helical flow directing structure, such as HFDS 2200, placed with internal cylinder, such as cylinder 2110, both as described in Fig. 2, inside an external cylindrical body with tangential top entrance for the input fluid, and bottom or top exit for the outgoing fluid and residual collection tank at the bottom, thereby forming a simple and cheap effective separator.

[0038] In some embodiments, additional line elements may be added, connected upstream of the CS or downstream, as may be needed. Such line elements may be one-way valve, manual isolation valve, line filter and the like.

[0039] While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those of ordinary skill in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

Claims

1. A centrifugal separator (CS) for separating suspending particles from a fluid, comprising:

an external circular body having a top cover and a bottom cover and a central longitudinal line;

a flow diffuser disposed at the upper part of the CS and concentric with the central longitudinal line, the flow diffuser comprising:

plurality of helical partitions;

a top disc plate; and

a bottom disc plate,

wherein the plurality of helical partitions are disposed between the top and the bottom plates, extending from an inlet hole made in the bottom plate to the circumference of the bottom plate, circularly evenly distanced from each other, thereby forming plurality of small helical flow diverting paths between each pair of adjacent partitions, the top disc plate and the bottom disc plate;

an internal space separator disposed inside the external body and coaxially with it with respect to a central longitudinal line of the external body, the internal space separator defines a fluid flow circulation space between it and the external circular body underneath the flow diffuser; and

an inlet tube to provide pressurized fluid to the flow diffuser via its inlet hole.

2. The centrifugal separator of claim 1, further comprising:

an outlet tube to provide exit path for the fluid, the outlet tube is disposed concentric with the central longitudinal line, internal to the internal space separator and external to the inlet tube thereby leaving flow path between the outlet tube and the inlet tube.

3. The centrifugal separator of claim 1, further comprising: a disposal tank connectable at the bottom of the external body and with free passage for disposable particles from the external tank to the disposal tank.

4. The centrifugal separator of claim 1, further comprising:

a helical flow directing structure disposed in the space between the external body and the internal space separator, adapted to direct flow leaving the flow diffuser circularly down inside the space between the external body and the internal space separator.

5. A centrifugal separator (CS) for separating suspending particles from a fluid,

comprising:

an internal space separator disposed inside the external body and coaxially with it with respect to a central longitudinal line of the external body, the internal space separator defines a fluid flow circulation space between it and the external circular body;

a helical flow directing structure disposed in a space between the external body and the internal space separator adapted to direct incoming flow of fluid helically from the top of the centrifugal separator downwardly; and

6. A method for separating particles from a fluid in a centrifugal separator,

comprising:

(a) forcing stream of fluid containing suspended contaminant into a central entry of a diffused, the diffuser is positioned with its fluid entrance aligned with a central longitudinal line of the separator;

(b) forcing the stream entering the diffuser, through plurality of helical partitions disposed inside the diffuser thereby creating plurality of deflected streams leaving the diffuser in a direction from the center of the separator towards its external body, the plurality of deflected streams to impinge the inner face of the external body at a defined tangential angle;

(c) allowing the fluid to circularly flow inside the body downwardly while gradually been separated from the suspended contaminant which tends to be forced to the body wall due to the centrifugal force;

(d) forcing the resultant fluid upwardly through an internal larger tube and down again through a coaxial smaller internal tube toward the outlet of resultant fluid from which contaminant was separated; and

(e) allowing contaminant particles that were separated from the fluid to be collected at the bottom of the separator and into a disposal tank.

7. The method of claim 6, further comprising:

after stage (b) directing the stream forced out of the diffuser in a helical path along the inner circumference of the diffuser body using an internal helical structure.

8. The method of claim 6 or 7 further comprising controlling the operation of the separator by means of a flow regulator disposed between the entrance of the contaminated fluid and the separator.