US3394879A - Continuous flow centrifuge - Google Patents

Description

July 3o, 1968 R. J. EBBERT 3,394,879

CONTINUOUS FLOW CENTRIFUGE INVENTOR,

July 30, 1968 R. J. EBBERT CONTINUOUS FLOW CENTRFUGE Filed sept. 1,

2 Sheets-Sheet 2 United States Patent O 3,394,879 CONTINUOUS FLOW CENTRIFUGE Robert J. Ebbert, 185 E. Avon Road, Rochester, Mich. 48063 Filed Sept. 1, 1966, Ser. No. 576,734

' 5 Claims. (Cl. 233-21) ABSTRACT OF THE DISCLOSURE This invention relates to cent-rifuges for removal of foreign particles from fluids, and more particularly to continuousow centrifuges in which the accumulated solids are periodically removed from the centrifuge.

It is an object of the invention to provide a novel and improved continuous iiow centrifuge in which the accumulated solids may be periodically removed without stopping rotation of the machine.

It is another object to provide an improved centrifuge of this type which will greatly reduce the possibility of damaging vibration due to wave disturbances during operation, a problem which is commonly present in conventional type centrifuges.

It is also an object to provide an improved continuous liow centrifuge of this type in which the iiow rate may be easily controlled so as to be uniform.

It is another object to provide an improved centrifuge having these characteristics, which is of relatively compact construction and is economical to manufacture and maintain.

Other objects, features and advantages of the present invention will become apparent from the subsequent description and the appended claim, taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a side elevational View in cross section of the centrifuge of this invention;

FIGURE 2 is a top plan View of the centrifuge, parts being broken away; and

FIGURE 3 is a fragmentary cross-sectional View in elevation taken along the line 3-3 of FIGURE 2 and showing the spaces between the radial guide vanes.

Briefly, the illustrated embodiment of the invention comprises a cylindrical stationary casing which encloses a cylindrical rotating housing, the housing being of generally flat shape. The rotating housing has a cylindrical outer wall, an inwardly extending annular flat lower wall, and a fiat upper wall which is secured to a hollow shaft rotatably mounted in the cover of the stationary casing. Means are provided for continuously rotating this hollow shaft, and its attached housing, and liuid to be cleaned is delivered down through the shaft. A circular flat plate is secured slightly below the upper wall of the rotatable housing so that the liuid delivered down through the shaft `will flow outwardly in the space between this plate and wall. Radially extending guide vanes are provided in this space Ito prevent spinning of the fluid.

The fluid will collect in the space surrounded by the outer portion of the upper wall, the outer wall, and the inwardly extending lower wall of the rotating housing, the entrained foreign particles being forced outwardly by centrifugal force against the outer housing wall. A plurality of downwardly extending radially disposed rectangular plates, referred to as paddles, are provided at the outer portion of the upper housing wall, the height of these paddles being substantially less than the height of the housing between its upper and lower walls. These paddles ICC will serve to carry along the newly entering fluid at the same angular velocity as the housing and the fluid within it. The paddles will also have the function of preventing the buildup of wave disturbances which could be created during operation of the centrifuge, and which might otherwise result in a magnified disturbance causing harmful Vibration or shaking of the machine. Furthermore, the paddles will tend to prevent the formation of such waves in the rotating fluid when the machine is disturbed by an outside force.

The cleaned liuid will exit past the inner edge of the annular lower wall of the housing and be thrown outwardly to the fixed casing from where it can be drained.

A solids removal scoop is also provided within the rotatable housing, this scoop being rotatably mounted on a vertical axis by a tube extending down through the fixed casing, and being movable between a retracted position spaced radially inwardly from the outer housing wall, and an operative position adjacent this wall. The rotatable mounting tube for the scoop will receive the solids caught by it, these solids being forced down into the shaft by a helically shaped vane.

Referring more particularly to the drawings, the centrifuge is generally indicated at 11 and comprises an outer casing generally indicated at 12 which is supported by a frame or stand, partially indicated at 13. Casing 12 is of flat cylindrical shape, having a cover 14 secured thereto by means of a flange 15 on the casing and bolts 16 extending therethrough. The lower portion 17 of the casing is saucer-shaped, a large central opening 1S being formed therein. A circular dam 19 is secured to the interior of bottom 17 of the casing some distance outwardly from opening 18, and a drain opening 21 is formed in bottom 17 immediately outwardly of darn 19.

A hollow shaft 22 extends downwardly through the central portion of casing cover 14. An antifriction bearing 23 is secured to cover 14 and supports the lower end of shaft 22. A superstructure 24 is carried by cover 14 surrounding bearing 23 and extending upwardly therefrom, a bearing 25 being supported by the upper end of the superstructure and rotatably supporting the upper portion of shaft 22. An electric motor 26 is secured to one side of said superstructure 24, and is connected to the upper end of shaft 22 by a belt 27 and pulleys 28 and 29. Motor 26 is of a type capable of rotating shaft 22 at sufficient speed to create the centrifugal action described below. The upper end of shaft 22 is connected by means (not shown) to a source of fluid which is to be cleansed. Such uid may be heat treat quench oil, oil for electrical discharge machines or any fluid having foreign particles capable of removal by centrifugal action.

A flange 31 is secured to the lower end of shaft 22 below cover 14, this iiange supporting a centrifuge housing generally indicated at 32. This housing is of fiat cylindrical sha-pe, having an outer wall 33, an upper wall 34 and a lower wall 35. The weight of housing 32 and shaft 22, as well as their attached parts, is carried by a collar 36 secured to shaft 22 above bearing 23 and resting on bearing housing 37.

The inner portion of upper wall 34 of housing 32 is secured to flange 31 by bolts 38, these bolts also passing through a fiat circular plate 39 spaced a short distance below and parallel to wall 34. The outer diameter of plate 39 is somewhat less than the diameter of outer wall 33 of the housing. Flange 31 is centrally recessed to provide a chamber 41 between shaft 22 and plate 39, this chamber leading outwardly to the space between plate 39 and upper wall 34 of housing 32.

A plurality of radially extending guide vanes 42 are disposed in the space between plate 39 and upper wall 34 of the housing. The shape of these guide Vanes is best seen in FIGURES 2 and 3, the vanes having tapered inner ends 43 adjacent space 41 and extending outwardly past the outer edge of plate 39 to the vicinity of side wall 33 of the housing. Six such vanes are shown in the illustrated embodiment, although the number and shape of the vanes could be varied to suit requirements. The shape of vanes 42 is such, however, that there will be no restriction of outward flow of the fluid as it passes downwardly through shaft 22 and outwardly from space 41 into the spaces between the varies. Bolts 44 are provided for securing the mid portions of vanes 42 to plate 39 and wall 34 of the housing.

A plurality of radially disposed paddles 45 are secured to the outer portions of vanes 42 beyond the edge of plate 39, these paddles extending downwardly about one-third of the distance from the upper wall 34 to the lower wall 35 of housing 32. Paddles 45 are in the form of plates which may be secured to vanes 42 by welding or similar fastening means, and they are of rectangular shape. Six such paddles are shown in the illustrated embodiment of the invention.

Lower wall 35 of housing 32 is spaced slightly above darn 19 and extends inwardly a slight distance past this darn, the wall having a rather large central opening 46. A fixed tube 47 extends upwardly through the inner portion of bottom 17 of casing 12 and past dam 19, this tube passing upwardly through opening 46. The tube rotatably supports a solids removal tube 48 which extends therethrough. A scoop 49 is secured to the upper end of tube 48. The configuration of scoop 49 is best seen in FIG- URE 2, the scoop having a curved shape with a mouth 51 opposing the direction of rotation of housing 32, which is indicated by the arrow 52 in FIGURE 2. Tube 48 is rotatable along with scoop 49 to move the scoop from its operative position shown in dotted lines in FIGURE 2 to a retracted position shown in dot-dash lines in this figure. In its operative position, mouth 51 is very closely adjacent outer wall 33 of housing 32 and slightly above lower wall 35. In its retracted position, the scoop will be clear of the space between upper wall 34 and lower wall 35, which is the space occupied by the fluid being cleansed, as described below.

Scoop 49 is connected with the upper end of tube 48, and a curved guide vane 53 is provided at the juncture of the scoop and tube so as to guide solids downwardly as they are forced to the interior of the scoop.

In operation, with scoop 49 in its retracted position, motor 26 will rotate shaft 22, housing 32 and their attached parts at high speed. Fluid to be cleansed will flow downwardly through shaft 22 and outwardly through chamber 41 and the spaces between guide vanes 42. The fluid might occupy a volume indicated at 54 in FIGURE 2 between each adjacent pair of guide vanes. As the uid reaches the outer edge of plate 39, it will flow into the volume surrounded by the outer portion of upper wall 34, outer wall 33 and lower wall 35 of housing 32. This volume is indicated in dot-dash lines at 55 in FIGURE l. The fluid will gradually lill this volume, being held in position by centrifugal force. The uid will of course contain entrained particles of dirt or other foreign matter, and these will be forced outwardly against wall 33, eventually occupying the volume indicated approximately by double dot-dash lines at 55 in FIGURE l.

After the fluid completely occupies space 55, additional quantities of fluid added to this volume will cause the cleaned fluid to pass the inner rim of wall 35 surrounding space 46, and the fluid will ow outwardly along the underside of wall 35 into the space 57 above bottom 17 of casing 12 and outside dam 19. The fluid will collect in this space and will exit via drain 21.

When it is desired to remove the accumulated solids in volume 56, scoop 49 will be rotated to its operative position as shown in dotted lines in FIGURE 2. Shaft 22, housing 32 and the parts attached thereto may continue to rotate during this portion of the operation, although Cal Cil

the fluid delivery to the top of shaft 22 may be halted in order to avoid unnecessary loss of fluid. The scoop will remove the solids accumulated in volume 56 along with some entrained uid, and these solids will pass toward the inner end of scoop 49 and, guided by vane 53 will pass downwardly through tube 48. The scoop may then be returned to its retracted position and the fluid inflow resumed through shaft 22.

The presence of paddles 42 constitutes a major feature of the present invention. It has been found that these paddles prevent the creation of a vibration effect which has been found to exist in conventional centrifuges of this type. This vibration effect is normally created in these conventional machines by some disturbance which creates a wave in the fluid being cleansed. The wave apparently reinforces itself to a degree which creates violent shaking of the centrifuge, creating the possibility of damage and in any cease reducing the life of the machine.

The presence of paddles for some reason prevents these disturbance-caused waves from becoming self-perpetuating or increasing in size, and has been found to practically eliminate the possibility of vibration or shaking due to their occurrence. While the exact reasons for this phenomenon are not entirely known, the paddles do carry along the Huid in volume at substantially the same angular velocity as housing 32, and this seems to have a beneficial effect. Moreover, the paddles apparently act as dampers or barriers to prevent waves created in the fluid from traveling around the periphery of the housing to a substantial degree, and this damping effect prevents reinforcement of the original wave by such travel.

It should be observed that since paddles 45 are substantially less in height than the total distance -between the top and bottom of housing 32, they will not interfere with the accumulation of solids in volume 56, which will normally occur to an increasing depth in a downward direction.

While it will be apparent that the preferred embodiment of the invention disclosed is well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

What is claimed is:

1. In a continuous flow centrifuge, an outer casing, a housing rotatably mounted within said casing, said housing having a circumferential outer wall, an upper wall and a lower wall, a hollow shaft at one end of said housing and extending axially therefrom, means for rotating said housing, a circular plate secured below the upper wall of said housing, a space being formed between said one end of said shaft and the central portion of said plate to receive fluid delivered through said shaft, the outer diameter of said plate being less than the diameter of said outer housing wall, a plurality of guide vanes extending outwardly between said plate and the upper wall of said housing, and a plurality of paddles disposed below said upper housing wall between the outer edge of said plate and the outer wall of said housing, said paddles being of substantially less height than the distance `between the upper and lower walls of said housing.

2. The combination according to claim 1, the upper edges of said paddles being secured to the outer ends of said guide vanes.

3. The combination according to claim 1, the lower wall of said housing being of annular shape and extending inwardly from said outer wall about the same distance as said paddles, whereby fluid acumulated in the space between said upper and lower housing walls will be carried along by said paddles and will also overflow past the inner edge of said lower housing wall, and means on said casing for draining overflow fluid therefrom.

4. In a continuous flow centrifuge, an outer casing, having a cover, a housing rotatably mounted within said casing, said housing having a circumferential outer wall, an

5 upper wall and a lower wall, a hollow shaft secured at one end to said housing and extending axially therefrom, said shaft extending through said cover, a bearing housing secured to said cover, a bearing held by said bearing housing and rotatably supporting said shaft, a collar on said shaft resting on said bearing housing -to support the weight of the shaft and the housing secured thereto, a superstructure mounted on said cover, an upper bearing carried by said superstructure and rotatably supporting the upper end of said shaft, an electric motor carried by said superstructure and connected to said shaft, a circular plate secured below the upper wall of said housing, a space being formed between said one end of said shaft and the central portion of said plate to receive iiuid delivered through said shaft, the outer diameter of said plate being less than the diameter of said outer housing wall, and a plurality of guide References Cited UNITED STATES PATENTS 487,055 11/ 1892 Ohlsson. 528,681 1l/1894 Ohlss-on 233--22 XR 884,830 4/ 1908 Lindahl. 2,431,142 11/ 1947 Schutte 233-22 XR 3,075,693 1/1963 Dega 233--28 XR 3,104,225 9/1963 Di Benedetto 233-28 HENRY T. KLINKSIEK, Primary Examiner.

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