US3774840A

US3774840A - Centrifugal separator

Info

Publication number: US3774840A
Application number: US00218149A
Authority: US
Inventors: D Boatright
Original assignee: ENVIRONS DEV Inc
Current assignee: ENVIRONS DEV Inc
Priority date: 1972-01-17
Filing date: 1972-01-17
Publication date: 1973-11-27
Anticipated expiration: 1990-11-27

Abstract

This invention describes a centrifugal separator which comprises a rotating chamber in the shape of an inverted truncated right circular cone with an inner cylinder providing a vertical downward-going circuit. The chamber is divided into a plurality of sectors by radial triangular walls and has a circular top plate which seals the large end of the chamber. The rotating chamber is surrounded by a closed housing. In the lower end of the housing are two concentric pipes, an outer and an inner pipe. The fluid to be separated enters and flows upwardly in the annular space between the outer and inner pipes and enters the rotating chamber. Here it is held in the separate sectors by the dividers, where it is rapidly rotated. As the fluid rises in the chamber, it is separated horizontally, the denser portions moving to the outer radius of the chamber, and the less dense portions moving to the inner wall. There are a plurality of holes in the top plate at the outer extremity of the chamber. There is also a plurality of holes near the top of the inner wall. The dense portion of the fluid moves upwardly and passes through the holes in the cover plate and into the housing, while the less dense components flow through the openings in the inner wall and pass downwardly through the inner pipe to an outlet. There is a drain pipe and valve in the bottom of the housing so that the dense fluid can be drawn off at that point.

Description

[111 3,774,840 [451 Nov. 27, 1973 CENTRIFUGAL SEPARATOR [75] Inventor: Donald Boatright, Tulsa, Okla.

[73] Assignee: Environs Development Inc., Tulsa,

Ok a.

[22] Filed: Jan. 17, 1 972 [21] Appl. No.: 218,149

[52] US. Cl 233/14 R, 233/16, 233/32, 233/47 R, 233/1 A [51] Int. Cl B04b 15/02 [58] Field of Search 233/] A, 1 R, 27, 233/28, 21,22, 13, 14 R, 14 A, 32, 47 R, 44, 233/16 [56] References Cited UNITED STATES PATENTS 3,219,264 11/1965 Cox 233/13 3,231,185 l/l966 Podbielniak... 233/21 X 2,710,718 6/1955 Denman 233/21 X 958,770 5/1910 Richardson 233/19 R Primary ExaminerGeorge H. Krizmanich Attorney-James R. Head [57] ABSTRACT This invention describes a centrifugal separator which comprises a rotating chamber in the shape of an inverted truncated right circular cone with an inner cylinder providing a vertical downward-going circuit. The chamber is divided into a plurality of sectors by radial triangular walls and has a circular top plate which seals the large end of the chamber. The rotating chamber is surrounded by a closed housing. in the lower end of the housing are two concentric pipes, an outer and an inner pipe.

extremity of the chamber. There is also a plurality of holes near the top of the inner wall. The dense portion of the fluid moves upwardly and passes through the holes in the cover plate and into the housing, while the less dense components flow through the openings in the inner wall and pass downwardly through the inner pipe to an outlet. There is a drain pipe and valve in the bottom of the housing so that the dense fluid can be drawn off at that point.

9 Claims, 2 Drawing Figures United States Patent 1 Boatright 3,774, 40 [451 Nov. 27, 1973 CENTRIFUGAL SEPARATOR BACKGROUND OF THE INVENTION This invention is in the field of centrifugal separators. More particularly, it is concerned with the separation of two-fluid mixtures and fluid-solid mixtures.

In the prior art there are a large number of patents indicating centrifugal separators of the general class of this invention. However, this invention differs from most of those in the prior art in several ways.

Specifically, the rotating assembly or chamber involves an upwardly expanding conical shaped chamber with means for introducing the fluids to be separated in an upward direction into the bottom of the rotating chamber. Also, there are a large plurality of separate sectors which hold the fluid and prevent it from flowing turbulently and mixing so that in the relatively quiet flow in'the sectors the parts of'the mixture of different density can migrate inwardly to the openings in the inner wall and outwardly up along the slope of the'conical surface and through the openings in the cover plate and then into the space within the housing, Also, this invention differs from the prior artin the provision of a sealed housing around the rotating chamber within which a selected back pressure can be maintained.

SUMMARY OF THE INVENTION This invention involves a rotating assembly comprising a rotating chamber which is iri'the shape of an inverted cone It is formed between an outer wall which is in the shape :of a truncated right'circular conical shell. There is an inner cylindrical wall and a circular top cover plate holding all the parts together securely. The space between the outer wall and the inner wall is divided into a plurality of sectors by thin triangular sheet separators. The entire rotating assembly is supported by a central vertical shaft which is held in bearings and is driven by motor means. There are two concentric pipes, an inner and an outer pipe downwardly depending from the rotating assembly. These fit into corresponding'sleeve hearings in a pair of concentric pipes. The input fluidmoves up the'annulus between the inner and outer pipes; past the bearing section and into the inner'and outer pipes of the rotating section and into the sectors of the rotating chamber. The fluid is permitted to pass out of the sectors through a first set of openings in the top cover plate at the outer radius of the chamber and a second set of openings in the inner wall at the top thereof. The less dense fluid then passes through these holes in the inner wall and passes downwardly through the inner pipe to the outlet. The dense portions pass through the holes in the circular cover plate and into the space outside of the rotating assembly which is enclosed in a rigid circular housing, which is supported by a framework from the floor. The dense component of the mixture passes into the housing and preferably fills the entire housing. An outlet pipe and valve are provided so that the upward flow can be constricted, providing a selected back pressure against the inner flow of the liquid mixture.

In the prior art there are a number of patents illustrating centrifugal separators of the general type of this invention. However, most of them involve downward flow of the fluid to be separated, some of them in an expanding conical shaped chamber. However, no art has been discovered which show all of the construction and cates generally, the rotating assembly. Numeral 12 inadvantages of this invention, in particular, the upward flow of the entering fluid, the upward expanding conical shaped rotating chamber and the sectors which are formed by the plurality of radial vanes held in the rotating assembly. Also, the concept of a completely enclosed pressure type housing in which a back pressure can be maintained, is not taught in the prior art.

BRIEF DESCRIPTION OF THEDRAWING It is a primary object of this invention to provide a centrifugal separator suitable for the separation of liquid mixtures where there are liquids of two different densities in the form of emulsions, etc., and in the separation of liquids with finely divided dispersed solids.

It is a further object to provide a centrifugal separator in which the entire separator system can be maintained under a selected back pressure to facilitate the separating process.

These and other objects of this invention and a better understanding of the principles and details of the invention will be evident from the following description taken in conjunction with the appended drawings in which: 7

FIG. 1 shows in section a vertical elevation of the preferred embodiment of this invention, and

FIG. 2 shows a detail of the openings in the cover plate.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, the numeral 10 indidicates generally the input portion of the equipment, while numeral 14 indicates the output portion of the equipment. Numeral 16 indicates generally the housing which encloses the entire fluid system, while'numeral 18 indicates generally the bearing and drive portion of therotating assembly.

The rotating assembly comprises a vertical shaft which supports by means of a fixture '62 and bolts '66,

a rotating chamber 10. The chamber is comprised of an inverted right circular conical shell 20 with a circular plate 24. attached to the shell a't-its broadest end, the plate 24 being supported by the fixture 62. The cham ber has an inner wall 22 which comprises a right circular cylinder, which is supported from the cover plate 24. The inner volume between the outer wall or conical shell 20, and the inner wall or cylindrical wall 22 is di- I vided into a plurality of sectors by means of closely spaced radial triangular sheet dividers 26. These are fastened to the inner wall 22 and the cover plate 24 and inner pipe 41. The outer and inner pipes are concentric and cooperate with bearings supported by a second set of concentric pipes. An outer pipe 36 and an inner pipe 38 are supported from a stable framework which is part of the housing, which will be described later. The outer and

inner walls

36 and 38

carry bearings

39 and 40 which cooperate with the upper rotating outer and

inner walls

42 and 41 and provide a seal between the rotating assembly and the input and

output sections

12 and 14. The input fluid passes through pipe 34 into the annular space between outer and

inner pipes

36 and 38 up through the rotating outer and

inner pipes

42 and 41 in the direction of arrow 44 into the sectors formed by the dividing walls 26. The fluid is then restrained by the dividing walls to turn with the rotating chamber. As the fluid is driven at the speed of the rotating assembly, the centrifugal force on the two components of the mixture cause the denser component to move radially outwardly and upwardly while the less dense component moves radially inwardly and upwardly. The less dense component then passes through the openings 32 in the inner wall 22 and thence downwardly through the inner pipe in accordance with arrow 47 and out through discharge pipe 48. The dense component moving up the outer wall passes through the openings 30 in the cover plate and into the space around the rotating chamber which is enclosed in a rigid housing 16. This comprises a bottom portion 53, a cylindrical portion 52 which are welded together and supported on legs 58. There is a cover 54 which is supported by'means of flange 55 by the cylindrical portion 52, the two being held together by means of bolts 56. The input and

output sections

12 and 14 including the outer and inner pipes are supported by flange 50 which is supported by a downward appendage of the housing and held by bolts 49. Thus, by removing bolts 49, it is possible to drop the

sections

12 and 14 vertically downward to. free the rotating assembly with'its inner andouter pipes. Then, by taking off the cover of housing 54 it is possible to lift out the rotating assembly to make any changes or maintainance that might be required.

There is a pipe 59 and valve 60 in the bottom portion 53 of the housing which permits the outward flow of the dense component of the mixture from the interior of the housing. On the cover of the housing there is an upward extension enclosed by a plate 72 which supports a seal 68 and a guide and thrust bearing 69, surrounding the vertical shaft 64. Drive means are indicated generally by the dashed outline 70 which can be a direct connected motor, or belt drive system, etc., which are well known in the art.

In operation, the rotating assembly is started, and the input two-component mixture is applied through pipe 34. It flows up the annulus 37 between the inner and

outer pipes

36, 38, and following arrow 44 into the sectors in the rotating chamber. There the lighter component is driven by centrifugal force through the holes 32 on the inner cylinder in accordance with arrow 46, and downwardly through the inner pipe in accordance with arrow 47 and out through pipe 48. The dense component passes upwardly and outwardly through the openings 30 in the cover plate and following arrow 45 down into the housing and thence out through pipe 59 through valve 60.

In a centrifugal separator of the kind illustrated, as the chamber is rotated, the liquid-gas interface will take on a concave shape, dependent on the rate of rotation. At low rates of rotation, the surface will resemble dashed line 87, with a slight depression. As the rate of rotation is increased, the liquid-gas interfacewill show a deeper depression, such as 88, 81, etc., with the higher gravity liquid toward the outside of the chamber below the interface lines 81, 88, etc.

As a liquid mixture is pumped in at 34 it will flow between the interface 81 and the wall 20, and out through 4 openings 30, into the housing space 84, collected at and out of the housing through pipe 59 and valve 60. Ordinarily no liquid, but usually gases will flow out through openings 32.

Now consider that the valve 60 is closed. As the mixture is pumped in through 34 under pressure, the mixture will flow out through openings 30 until the

space

84, 85 in the housing is completely filled. Then no more liquid can flow out through openings 30. Thus, under the pressure of the input mixturethe liquid level will rise inside the chamber, roughly in accordance with dashed lines 81, 82, 83, etc., until the chamber is filled, and then it will flow out through openings 32.

Neither of these extreme conditions is desirable since there will be no separation of liquid components. That is, all of the liquid will flow out either through 30 or out through 32. What is needed is a flow through both sets of openings. This can be done by opening valve 60, reducing the back pressure on the openings 30. With flow out of both sets of openings there will be separation. The flow through each set of openings should be roughly proportional to the percentages of each component in the mixture to get the best separation. This is controlled by the back pressure, as set by the valve 60, and indicated by gauge 93.

If the dense component is a viscous sludge, then there will be considerable friction between the rotating chamber and the sludge filling the housing. in that case,.

the sludge level can be reduced to a level such as that indicated by the dashed line 72, or lower, provided that the back pressure on the openings 30 can still be maintained. This can be done by filling the space 84 above the liquid surface 72 by gas pressure, through pipe and valve 91.

Thus the housing can be run full, under control of valve 60, or it can run partly full under control of valve 60 and gas (air) pressure in the housing, of such pressure as to provide a back pressure on openings 30, suitable for the separation desired.

In FIG. 2 is shown a different embodiment of the openings 30 in the cover plate 24 of the chamber 10. By making them of the shape shown, that is, with a backward direction, and expanding cross-section, the rotating top plate 24 (when the chamber is'filled with liquid) will act as an impeller of a pump and will provide an increased liquid pressure at the outlet of valve 60.

i In separating various mixtures of liquids, such as emulsions it is often necesary to pretreat the liquids with suitable chemicals (well known in the art) so as to permit the small droplets to combine into larger ones, which are more amenable to gravity separation.

This invention contemplates the introduction of such chemicals into the inlet of the separator. Such a stream 78 of chemical can be introduced through pipe 76 into the main inlet pipe 34. Thus, there will be two streams; the stream 80 of liquid mixture to be separated, and the smaller stream 78 of chemical. They will mix during the flow up to the rotating chamber, and the chemical added will assist in the separation. This will permit separation at lower centrifugal forces corresponding to lower rates of rotation.

When the interior of the housing 16 runs full of liquid, or sludge, restrained by back pressure at valve 60 the pressure at the outlet 60 can be built up by shaping the openings 30A as shown in FIG. 2. The same effect can be obtained on the openings 32 of the inner wall 22 may be made in the details of construction and the arrangement of components. It is understood that the invention is not to be limited to the specific embodiments set forth herein by way of exemplifying the invention, but the invention is to be limited only by the scope of the attached claim orclaims, including the full range of equivalency to which each element thereof is entitled.

What is claimed is:

1. A centrifugal separator comprising:

a. a rotating chamber defined by an outer wall in the shape of an inverted truncated right circular cone and an inner wall in the shape of a right circular cylinder, a plurality of radial triangular sectors dividing the space between said walls into a plurality of sectors and a circular cover plate covering the top of said chamber;

b. an outer pipe secured to said outer wall and an inner pipe secured to said inner wall, defining an annular conduit therebetween, said pipes connected to said chamber, for carrying input fluid up into said chamber;

c. a plurality of first openings in said cover plate, at least one for each sector placed at the outer radius of said chamber;

d. a plurality of second openings in said inner wall near the top thereof, the interior of said inner wall communicating vertically downward through said inner pipe;

e. housing means surrounding said rotating chamber,

and means to draw fluid from said housing, said pipes sealed for rotation, through said housing; and

f. means to rotate said chamber and pipes in one direction.

2. The centrifugal separator as in claim 1 in which said means to rotate comprises a central shaft supporting said rotating chamber, bearings on said shaft to rotatably support same to said housing, and including motor means.

3. The centrifugal separator as in claim 1 in which said outer and inner pipes are constructed of two sets of inner and outer pipes, a first set attached to said inner and outer walls and a second set attached to said housing, bearings rotatably supporting said first set bemeans to control the outflow of fluid from said housing.

6. The centrifugal separator as in claim 4 including means to introduce a compressed gas into said housing to control the fluid pressure.

7. The centrifugal separator as in claim 1 in which said first openings in said cover plate are sloped backward against the said direction of rotation of said chamber.

8. The centrifugal separator as in claim 1 including means to proportionately introduce treating chemicals into said input fluid.

9. The centrifugal separator as in claim 1 in which said second openings communicate with short pipes depending downwardly and backwardly against the direction of rotation of said chamber.

Claims

1. A centrifugal separator comprising: a. a rotating chamber defined by an outer wall in the shape of an inverted truncated right circular cone and an inner wall in the shape of a right circular cylinder, a plurality of radial triangular sectors dividing the space between said walls into a plurality of sectors and a circular cover plate covering the top of said chamber; b. an outer pipe secured to said outer wall and an inner pipe secured to said inner wall, defining an annular conduit therebetween, said pipes connected to said chamber, for carrying input fluid up into said chamber; c. a plurality of first openings in said cover plate, at least one for each sector placed at the outer radius of said chamber; d. a plurality of second openings in said inner wall near the top thereof, the interior of said inner wall communicating vertically downward through said inner pipe; e. housing means surrounding said rotating chamber, and means to draw fluid from said housing, said pipes sealed for rotation, through said housing; and f. means to rotate said chamber and pipes in one direction.

3. The centrifugal separator as in claim 1 in which said outer and inner pipes are constructed of two sets of inner and outer pipes, a first set attached to said inner and outer walls and a second set attached to said housing, bearings rotatably supporting said first set between said two sets of pipes.

4. The centrifugal separator as in claim 1 including means to control the fluid pressure in said housing.

5. The centrifugal separator as in claim 4 in which said means to control the fluid pressure comprises means to control the outflow of fluid from said housing.