US1619652A - Centrifugal separator - Google Patents

Description

March 1 1927.

' B- C. CARTER GENTRIFUGAL SEPARATOR 5 Sheets-Sheet Filed Oct 1926 March 1, 1927. 1,619,652

B. C. CARTER CENTRI FUGAL SEPARATOR Filed Ogt 23, 1926 s Sheets-Sheet 2 March 1 1927.

B. C. CARTER CENTRIFUGAL SEPARATOR Filed Oct, 23, 1926 5 Sheets-Sheet 5' March 1 1927.

B. c. CARTER v CENTRIFUGAL SEPARATOR WNL.

March 1, 1927 1,619,652

B. c. CARTER CENTRIFUGAL SEPARATOR Filed Oct, 23, 1926 5 Sheets-Shec 5 V, &

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Patented Mar. 1, 1927.

BENJAMIN CHARLES CARTER, OF LONDON, ENGLAND.

CENTRIFUGAL SEPARATOR.

Application filed October 23,1926, Serial No.

This invention relates to centrifugal separators and consists in improved constructions of separator especially suitable for insertion in the oil circulating system of internal combustion engines for freeing the lubricating oil from fine solid matter; or for freeing fuel oil or other liquids from air or solid impurities; or for freeing air from solid and liquid impurities; and also applicable to other purposes.

The separators of the invention desi ned for cleaning liquids comprise a bowl filled with the liquid to be cleaned and rotating with it at a high speed, longitudinal vanes ensuring that the liquid adjacent to the bowl shall be at rest relatively to it, while fluid further removed from the surface of the bowl can flow slowly but freely along a path parallel with the axis of rotation and divided from the remainder of the bowl by a perforated wall or equivalent means which will permit the outward movement of solid particles of impurity undercentrifugal ac- ,tion but will tend to prevent; the aggregate or conglomerated deposit of impurity which collects within the bowl from returning into and choking the axial path.- The bowl and the perforated wall or equivalent dividing means are surfaces of revolution, conveniently right circular cylinders or barrelshaped, and theiraxis is the axis of revolution. The liquid to be cleaned may itself be caused to rotate the bowl and perforated cylinder; for this purpose the liquidmay be propelled into the separator through a helical passage of decreasing pitch formed in the stationary inlet; in its axial flow within the separator it may be guided parallel to the axis by longitudinal vanes in the per-, forated cylinder; and it may leave the separator through another helical path of decreasing pitch and opposite twist formed in the rotating outlet. The effectiveness of the separator may be increased by dividing the space between the bowl and the perforated cylinder by transverse partitions or vanes. Where the liguid contains impurities lighter than itsel theremay be a perforated cylinder bounding the axial liquid path on its'innersurface; and if the lighter impurities are gaseous, as 1n the case of 011 containing air, a relief valve may be provided to permit the escape of the gases from within this inner perforated wall.

143,725, and in Great Britain March 14, 1925.

In separators designed for cleaning air an mperforate bowl is not essential. 1s led through a erforated cylinder the central part of which .is filled by a stream lined body, which may consist of a rotating portion carrying the cylinder by radial The air vanes and a stationary portion containing the bearings of the rotating part. Such a separator may be driven, as above described, by the air to be cleaned being through it along suitable helical pat s, or it umped may be fitted with vanes which will cause its rotation when it it carried through the air at a high speed, as, for instance, upon an aeroplane. Y

Various embodiments of the invention are illustrated diagrammaticallv and byway of centrifugal separator through which the i liquid passes in several parallel streams;

Fig. 5 is a vertical section of part of a centrifugal separator for treating liquid containing air;

Figs. Sand 7 are .longitudinal and transverse sections ofa centrifugal separator for separating dust and sandfrom air;

Figs. 8 and 9 aresimilar views ofanother form of centrifugal separator for separating dust and sand from air; and Fig. 10 is a longitudinal section of a for of separator which is arranged vertically and in which certain shaped.

In the centrifugal separator shown, in

Figs. 1 and 2, an annular drum-is formed with a perforate inner wall '1, an imperferate outer wall or bowl 2,and imperforate annular ends 3, 4 connecting said walls. The drum is mounted in antifriction or other suitable bearings 5, 6 so as to offer little frictional resistance to rotation. A running gland 7 on the inlet end of the drum receives a stationary hollow inlet boss parts areimade barr'el- I 8 which communicates with the oil supply. The running gland may be formed with a helical groove 9, of opposite twist to the direction of rotation to aid in preserving a fluid tight running fit between the gland and the inlet boss 8. The drum communicat'esjwith the inlet boss 8 through the inlet end 10 of the inner wall 1, and with a receivin reservoir or communication (not shown through the outlet end 11 of the inner wall 1. The drum may be mounted in a stationary casing 12 of which the inlet boss 8 may form part.

The inlet boss 8 is fitted internally with one or more helical vanes 13 decreasing in pitch towards the rotary inlet 10, and forming a helical passage or passages of decreasing pitch and radial width between a central stationary cone 14 and the wall of the inlet boss 8. These helical paths terminate adjacent to the rotary inlet end 10 in jets of small cross sectional area. Within the inner wall 1 is a central rod or tube 15 of'the s'amediameter as the base of the cone 14. The annular space 16 between this rod or tube and the inner wall of the drum forms a direct oil passage-way through the drum, and is divided by approximately straight radial vanes 17 extending from end to end. Upon these radial vanes are de-' livered the streams of oil issuing from the jets and adjacent the inlet end 10.

The outlet end 11 of the divided annular space 16 communicates with the flared rotating outlet boss 18, which has one or more internal helical vanes 19, decreasing in pitch towards the outer end and twisting in the opposite direction to the helical vanes 13 in thestationary inlet boss 8. These direct the oil in the reverse direction to that of the rotation of the drum and convert into velocity the remaining pressure to which the oil is subjected during rotation of the drum.

The oil issues as jets which by their reaction assist in causing the drum torotate. The drum is ,thus driven in the manner of the rotor of a reaction turbine.

The straight radial vanes 17 may be curved at each end so that the oil is transferred to and from them with minimum shock and loss of energy.- 1

Within the bowl 2 are radial vanes 20 dividing it. into sectors, and compelling the oil to rotate with the bowl. If desired transverse vanes 21 may be fitted in the bowl dividing the annular quiescent space between walls 1 and 2 into separating zones.

Oil is delivered under pressure to the stationary inlet boss 8, and" the stationary helical vanes 13 in this boss cause the pressure of the oil to be partially converted into velocity at the exit jets of these vanes. The oil completely fills the annular space 16 and the bowl 2, and during its passage through the separator the oil travelling axially along the annular space is divided from the oil in the bowl by the perforate inner wall 1, The oil in the bowl is'thus practically motionless relative to the bowl. The axial velocity of the oil along the divided annular space 16 is small, and the.

tendency for turbulence .to "prevent separation of particles is thus keptlow, whereas the circumferential velocity is high enough to produce great centrifugal effects. Thus the oil is constrained to (pass slowly through the apparatus in a rapi ly rotating divided cylindrical sheet, and the particles of dirt have but a short distance to move radially in order totraverse the perforate inner wall 1 and become separated from the axially The angular velocity of the drum is made i high by making its efliciency as a turbine as high as possible and by diminishing the viscosity of the liquid. The viscosity of the liquid is made small by working at as high an oil temperature as possible.

The circumferential velocity of the drum at the region of entry 10 of the oil requires to be of the same order as the jet velocity from the stationary entry vanes 13. The latter is limited by the'pressure drop available, the viscosity of the oil, and the minimum jet area it is practicable to adopt. The radius of the stationary inlet vanes is therefore made small to obtain high rates of rotation, Y t

In the arrangement described the important centrifugal action takes place in the divided annular space 16 and the radius at which a particle is separated is equal to theradius of the stationary; inlet vanes. A

greater centrifuge effect may be obtained by leading the oil out. to, a larger radius during a part of its, travelthrough the apparatus, as by making the inner perforate wall 1 and tube 15' barrel-shaped (Fig. 10), the bowl2' andcasing 12' being made spherical in that event; for the same thickness of annular space,'the axial velocity in the part of greater diameter would be less and the time of traversing the apparatus greater, both of whichfactors tend to give improved separation. The annular space should be made as thin as possible, and the drum long and of small diameter (rather than short and of large diameter) so that the distance the particles have to pass radially to effect separation is small, and the time of traversing the apparatus is large.

Short tubular outward projections, indicated at 1 in Fig. 10, may be arranged at the holes in the perforate wall to prevent return flow from the annular bowl back into the annular space within the inner wall with accompanying return of particles; or, if preferred, the holes in the perforate inner wall may be-counter-sunk from either the outside or the inside, as indicated at 1 or both expedients may be adopted.

The retention of the particles within the annular drum involves some dgree of adhesion to the walls and caking of the deposit. It may be advantageous and desirable to give the walls a rough surface or to coat them with grease or other suitable substance to facilitate retention, but'with engine oil the natural gumminess of the de-v posit may sutlice. Cooling of the outside of the drum facilitates gumming and retention of deposit. For this purpose the drum may be provided with cooling fins 1 (Fig. 10), which may be. exposed to the atmosphere or other cooling medium. The inner perforate wall tends to check or prevent any flakes or deposit which may become detached from the wall of the bowl from re-entering the path along which the oil flows axially, as might otherwise happen when the apparatus is stopped or is being stziirted, and so obstructing the flow of the o1 For some purposes, for instance for separating water as well as solid impurities from gasoline, the device may be set with its axis vertical (Fig. 10) and the lowermost perforations in the wall 1.. may be omitted. By this meansthe lower end of the annular space between the walls 1f and 2 is wholly cut off from the through-flowing stream, and permits the undisturbed accumulation of any water tha-t may be separated from the gasoline.

Increased separation may be attained by passing the oil in parallel (Fig. 3) or in series (Fig. 4) axially through a system or nest of concentric or symmetrical'annular spaces 160 in a separatorhaving inner per forate walls 100 and outer imperforate walls 200, corresponding to the inner perforate wall 1 and the outer imperforate wall 2 in Fig. 1. In this arrangement alternate im perfora-teand perforate walls. are arranged etween the innermost and outermost walls of the drum, and the separated matter accumulates on the series of imperfprat'e walls.

or cylinders. This arrangement is directed mainly to extracting matter quickly. The

arrows in Figs. 3 and-4 indicate the direction of flow of the oil from theinlet end 10 of the divided annular space 160 to the It will be understood that the ends of the drum and the casing may be detachable, as

is shown for the inlet end of the drum and casing in Fig. 1, to facilitate access thereto for matter.

In treating oil containing air, the air tends to keep near the axis of, rotation under the centrifugal action, and, as shown in Fig. 5 a separate outlet 22 may be provided through which the air reaches a small relief valve 23 loaded to a suitable pressure and located in the central tube 15 forming the inner wall of the annular space 16. The

relief valve casing runs in a stationary gland 24, which can communicate with the atmospherethrough a cook 25.

cleaning out. the separated The separator as described maybe con 1 strueted small in size and light in weight, and has the important featurethat no mechanical high speed drive, or slipping clutch is involved. 1'

, Such a separatormay be incorporated in the sump of an aircraft or other internal combustion engine, which may be provided with two scavenging pumps, one at each end, each pump being more than capable: of dealing with the oil in circulation; Oil

cationyand fixed vanes may be used in the pipe line or reservoir.

In the form of construction of cei'itrifugal separator shown in Figs. 6 and 7,v the bowl is formed with a perforate inner wall 101 and an outer wall 20l which may be imperforate or perforate as indicated at 37. The bowl is mountedmon a central spindle 26, supported in antifriction bearings 27, 28 in an inner housin 29, which is located by means of radial we s or vanes 30 within an outer housing 31. The outer housing 31 is adapted to be applied to the air intake 32 to an internal combustion engine. Helical vanes 33 mounted within the entry of the bowl cause the air drawn in by the engine to rotate the bowl in flowing therethrough. I Radial vanes 34 mounted within the perforate inner wall 101 and which may be continuous with the vanes 33, divide the annular space 161 between the inner peripheral wall and the central body part,

150 into longitudinal air passage-ways.

Curved vanes 35 which may be continuous with the vanes 34' may be located within the outlet end of the bowl for straightening out the air stream before it passes into the air intake to the engine to prevent turbulence of the air in the intake. The vanes 30 may be curved for the same purpose. The central body 150 increases the mean radius ofairflow and has a streamline formation.

In addition to or in lieu of using helical vanes within the bowl for imparting a rotational effect to it, the bowl may be furnished with exterior helical vanes 36 or the like,

which are adapted to cause rotation of the bowl b the slip stream or relative air flow, when the separator is used in an exposed position on an aircraft or other moving vehicle.

In the form shown in Figs. 8 and 9,instead of the spindle 26 being secured to the bowl and rotating in hearings in a stationary housing 29 as in Fig. 6, it is secured in the stationary housing 29, and the bowl rotates in bearings 38, 39, on the spindle.

Further, instead of the plain perforate inner wall 101 as in Fig. 6, a series of annular partitions 102 may be employed, and the outer wall may be pocketed and perforated as at 202. The inner edges of the annular partitions 102 together with those of the radial vanes 30 form in eflect a perforate inner wall. v

A collector 40, inthe form' of a casing with a radial or outer outlet 41 may be attached tothe other stationary housing and perforate area.

extend over part of the bowl including the bowl rotatable at high speed upon itsaxis,

longitudinal vanes u on the inner surface of the wall of said bowl to said bowlat opposite ends thereof, and means continuously dividing the fluid path between said inlet and outlet from the remainder of the bowl throughout theentire length of the bowl said means permitting passage of fluid and fine. impur ties along such path while checking return of conglomerated solid matter to said path.

2. A centrifugal separatorv comprising a bowl rotatable at high speed upon its axis, longitudinal vanes upon the "inner surface of the wall of said'bowl, an inlet and an out- V let to said bowl at opposite ends thereof,

and a continuous perforated wall dividing the fluid path between said inlet and outlet from the remainder of the bowl throughout the entire length of the bowl; said wall per.-

This casing serves to gather the dust' or sandwhich has been separated .from the air.

, an inlet and an outlet mitting passage of fluid and fine impurities along such path while checking return of conglomerated solid matter to said path.

3. A centrifugal separator'comprising a rotatable bowl, inlet and outlet means admitting fluid to pass axially through said bowl, and vanes in the path of said fluid adapted to deflect the same and thereby cause rotation of said bowl.

4. A centrifugal separator comprising a rotatable bowl, a fixed inlet in line with the axis of said bowl, helical vanes in said inlet adapted to impart a whirling motion to fluid passing axially therethrough and eject it in the form of jets from said inlet, and

vanes in said bowl against which such jets impinge, thereby to cause rotation of the bowl.

5. A centrifugal separator comprising a rotatable bowl, a fixed inlet in line with the axis of said bowl, helical vanes in said inlet adapted to" impart a whirling motion to fluid passing axially therethrough and eject it in the form of jets from said inlet, vanes in said bowl against which such jets impinge so as to cause rotation of the bowl, an axial outlet rotating with said bowl, and helical vanes in said outlet extending in the opposite direction from the first-named vanes to convert the whirling motion of the fiuid in said bowl into a straight axial flow.

6. A centrifugal separator comprisin a rotatable bowl, longitudinal vanes wit in said bowl, a wall within the bowl having the form of a surface of revolution about the axis of rotation and being perforated from one end substantially to the other means admitting liquid to pass axially through the interior of said perforated wall from end to end thereof and to fill the bowl through the perforations, and means disposed axially of said separator for permittingthe escape of gases.

7. A centrifugal separator, comprising a rotary bowl having an inlet at one end and an outlet at the other and embodying connected outer and inner, substantiztlly-eylin drical members disposed in coaxial relation, the inner-member bein perforated from its inlet end approximate y to its outlet end;

and means, for admitting fluid at theinlet 'end of saidinner member to travel axially throughthe interior thereof. to the outlet whereby-matter to be separatedcontained in the traveling fluidwill be caused outward through the er-' uid end,

-mately to the other; a stationary cylindrical member extending axi 11y through said in- "ner cylindrical. member and roviding an radially outward through the perforations open-ended annular passa e t erebetween; as the axial movement of the fluid conand means for admitting uid at the inlet tinues. and of such lpassage to flow axially there- In testimony whereof I have signed my 5 throu h to t e outlet end of the passage, name to this specificationwhere y matter to be separated contained in 4 Y Y a the traveling fluid will be caused to pass v BENJAMIN-CHARLES CARTER.

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