US2106688A - Centrifugal machine - Google Patents

Description

Jan. 25, 1938. w. H. BATH CENTRIFUGAL MACHINE \Wmer h. Bath Filed Feb. 27, 1935 I FIG.1

A my;

. Mumm w a Patented Jan. 25, 1938 UNITED STATES PATENT OFFICE GENTRIFUGAL MACHINE Application February 27, 1935, Serial No. 8,459

2 Claims.

The present invention relates to the art of the centrifugal treatment of fluid substances. It is particularly concerned with improvements in the class of centrifugal machines in which a concentration of suspended solid materials within a liquid occurs during the feed of a suspension of solids in liquid to the rotor of the machine and the concentrated suspension is discharged thereafter intermittently from the machine by breaking the connection between two normally abutting portions of the machine to afford a discharge outlet for the suspension.

A centrifugal separator of this general type is disclosed in the patent to Nyrop 1,735,692 and the present invention was conceived as a solution of problems encountered in the application to commercial uses of machines of the general type of those forming the subject matter of the Nyrop patent. In the Nyrop invention of that patent, 20 a centrifugal rotor is illustrated which is formed in two parts, which are axially separable to afford provision for intermittent peripheral discharge of a concentrated effluent from the rotor. In the use of a machine of this type, it is necessary, in

25 order to prevent leakage, to provide a sealing member between the abutting axial separable portions I which control the intermittent discharge. Such sealing members are subjected to very severe erosion effects by reason of theim- 1 30 pingement of material thereagainst incident to 40 formable sealing material can be found and used eifecting a perfect joint, that these local deteriorations can be overcome to a large degree 5 and that the life of the sealing material will be greatly prolonged. It is therefore to the solution of this problem to which I have addressed myself.

Further objects of the invention and the man- 50 ner in which they have been attained will be in part pointed out hereinafter and will be in part obvious from a reading of the subjoined specification in the light of the attached drawing, in

which: 55 Fig. l is a central axial sectional view through Furtherunder conditions to bring the internal pressure of the bowl to apply to the sealing means for a centrifugal separator bowl illustrating the application of my invention;

Fig. 2 is an enlarged detail view of the separable peripheral portion of the bowl, and

Fig. 3 is a modified form of my invention em- 5 bodying, however, the same principles of operation.

Referring now more particularly to the drawing in which like reference numerals indicate like parts, the separator bowl comprises generally a 10 rotatable section I0 and a second section l2 which may be termed the bowl cover which is likewise rotatable but axially movable with respect to lower bowl section III. Adriven shaft H is provided and fixed within a boss l6 of the inner lower bowl section l8. The inner lower bowl section I8 and. the bowl cover 12 are attached in a suitable mannenso as to, in effect, constitute a unit which is adapted to rotate and to move axially as one. It is to be understood, of course, that the Whole bowl including the outer lower bowl member ID, the inner lower bowl member l8, and the cover member l2 partake of the same rotary movement imparted by the shaft [4.

The interior of the bowl tapers from both ends toward the middle and has its maximum interior diameter at the zone of junction betweenits opposed portions l2 and I8 and provided in that neighborhood are peripheral openings 20 which are adapted to discharge solid material when the discharge opening has been opened by a relative movement of the parts I 2 and I8 with respect to the outer lower bowl portion I0.- The movement of the bowl members l2 and I8 in an axial direction is accomplished by hydrostatic pressure developed under the inner lower bowl member l8 by the admission of liquid from a nozzle 22, which liquid finds its way through a channel 24 and into a space 26 under the lower inner bowl member I 8.

.- Suitable means, hereinafter described, have been provided for preventing the leakage of liquid be tween the buter lower bowl member ID and the inner lower bowl member l8.

flhe axially movable bowl members are returned to their lower position by means of a plurality of spring members, one of which is shown, at 28. As shown, the spring member 28 surrounds a bolt 30 which projects downwardly from the lower inner bowl member l8 through a suitable opening in the base of the lower outer bowl member it. One end of the spring 28 bears against the exterior of the lower outer bowl member ill while the other end of the spring is retained, by means of, a nut 32 screw threaded to the outer end of the bolt 30. Thus upon a raising of the bowl members I2 and I8 by hydrostatic pressure as hereinbefore mentioned, the spring 28 is compressed and upon the release of the hydrostatic pressure, the tension of the spring 28 will return the bowl members I2 and I8 to their lower position thus closing the discharge openings.

Material to be treated may be admitted through a distributing feed tube 84 to be discharged into the bottom of the bowl. Disc inset 35 of usual construction is illustrated and accelerating wings 38 of usual construction are provided. Upon rotation of the bowl, the solid material is forced to the outer portion of the bowl by centrifugal force in the well known manner,

' while lighter eilluent finds its way upwardly near the axis of the bowl. and is discharged through discharge ports 40'.

Axially movable bowl members I2 and I8 are guided in their movement by means of locating pins 42 fixed in the lower outer bowl member I0 and adapted to movein guideways 44 provided in the upper bowl member I2. .To guard the 10- cating pins 42 against excessive erosion and to prevent sludge from entering the guideways 44, I have provided replaceable guard sleeves 48 of wear resisting material which surround the pins.

The particular .bowl sealing means which forms the subject matter of this inventionwill now be described. The upper bowl member I2 is provided with a stepped circumferential groove 48 on its inner surface which groove is adapted to receive a sealing gasket 50. The sealing gasket 50 is constructed of any suitable deformable sealingmaterial and I have found that rubber or a composition thereof is satisfactory for this purpose. The sealing'member 50 is held in place by two sealing rings 52 and 54. After the sealing member 50 which, as may appear obvious is a relatively slender annular ring conforming to the inner contour of bowl cover I2, is placed in position, a retaining ring 52 may be fixed to the bowl cover I2 in anysuitable manner. Thereafter, an annular inner retaining ring 54 is placed in position and fixed to the upper bowl member I2 by means of bolts, one'of which is shown at 56. It will be noted that the retaining ring 52 is coextensive with the outer surface of sealing member 50, but that retaining ring 54 is not coextensive with the inner surface of the sealing member 50 but permits a small area at the lower edge of the same to be exposed for a purpose which will hereinafter be more fully described.

A second sealing member 80, similar in construction to the sealing member 50, is provided in the inner peripheral edge of the lower outer bowl member III. The sealing member 80 is held in position by means of a retainingring 62 fixed to the upper peripheral edge of bowl member I0 and a bowl lining member 84 on the interior of the lower outer bowl member I0. It will be noted that the liner 84 is beveled at its upper edge 66 and extends beyond the upper tapered edge of the relatively movable inner lower bowl member I8. This construction is provided to protect the sealing member 50 fromthe erosive effect of solids which may be caught between the liner 04 and-the inner lower bowl member I8. Furthermore, the liner 04 exposes but a small portion of the inner surface'of annular sealing member 80 and this surface is substantially equal to the eipo's'e'dinner surface of the annular sealing member 50 for a pu p o be hereinafter described. At the same time it will be noted that the inner edges of the retaining rings 52 and 52 are in abutting relation and form a continuous In the operation of this formof the invention,

during rotation of the bowl in the operation of centrifugal separation, a pressure is created at the outer edge of the bowl and this pressure effectively operates to cold flow the deformable material of the sealing members 50 and 60 into each other to form an absolutely tight seal irrespective of any irregularities which may be presented in the abutting edges of these seals and irrespective of local erosion. The pressure acting upon these sealing members is sufllciently great to bulge the'same into accurate sealing contact as shown at 68 in Fig. 2.

In describing the modified form of the invention shown in Fig. 3, I will use the same reference numerals used to describe the first embodiment of the invention wherever applicable, but with the addition thereto of I00. In this form of the invention, I have shown a fragment of the lower outer bowl member H0, the inner lower bowlmember H8, and the bowl cover H2. In this form of the invention, the bowl members H2 and H8 move axially with respect to the lower outer bowl member H0 and in this form of the invention, I have provided a single sealing member I 50 which is positioned in a recess in the bowl erosion by means of the retaining ring I54 which extends to the plane of the lower edge of the cover member H2 at the point where the same contacts the exposed edge of the sealing member I50. Thus the lower edge of the cover H2, the exposed edge of the sealing member I50 and a portion of the retaining ring I54 lie in substantially the same horizontal plane so that the discharge of solids over the exposed surface of the sealing member I50 is materially prevented from cutting the sealing member I50. However, erosion nevertheless takes place and to overcome the effects of local erosion and to insure a perfect seal between the annular projection I62 of the lower bowl member H0 and the exposed and abutting portion of the sealing member I50, I have'provided anovel means for utilizing the pressure within the bowl for forcing the sealing member I50 into tight contact with projection I62.

Bowl cover H2 is provided with an annular chamber 0 above the sealing member I50 and this chamber communicates by way of a plurality of channels I12 with ports I" in the retaining ring I54 and thus with the pressure within the bowl. In its closed position the sealing member I50 will therefore be carried into tight sealing contact with projection I62 whenever the bowl is operated and it follows therefore H0 is greater than, the area which may be exposed to bowl pressure at the joint-between the sealing member I50 and the bowl projection I62.

Furthermore, the chamber "0 is a greater radial distance from the axis of rotation than the inner exposed edge of the joint between the sealing member I50 and the bowl projection I62 and, therefore, is subjected to a greater pressure.

I have provided means for sealing the space between the lower bowl liner 64 and the lower inner bowl member I8 which comprises two annular flanged rings 80 and 82 which are held in a circumferential groove in the lower inner bowl member l8 and in spaced relation .by a spacing ring 84.. The flanged rings 80 and 82 are made of relatively flexible metal and to the vertical flanged portion of the ring 82 is fixed a lead weight 86 which is adapted to carry the vertical flanged portion of this ring into sealing contact with the liner 64 under centrifugal force. I have found in. the operation of thesemachines that under some conditions of operation, a metal to metal seal is not entirely satisfactory, and I have therefore provided the vertical flange of the ring 80 with an extension of flexible fabric 88 which is held between the ring 80 and a lead supporting and weighting member 90 so that the fabric is carried into perfect contact with the liner 64, thus fabric which has a greater capacity'for conforming to the contour of the liner 64 and which also has the peculiar characteristicof retaining an applied lubricant to a greater, degree.

In this specification I have described what I now consider the preferred embodiments of the invention, but it is to be understood that the comprising a, centrifugal rotor'and means for feeding to said rotor a fluid materialadapted to be subjected-to centrifugal treatment, said rotor including a separating chamber, a pair of.separable portions extending annularly about the all! of the rotor and mounted to be movable relative to each other only in an axial direction and normally retained in abutting relationship to prevent the discharge of material from said chamber, means for separating said portions to aflord provision for discharge of material from said chamber, and means for sealing said chamber against discharge of material between said portions when in abutting relationship, said means comprising annular abutting sealing members carried in the periphery of and positively attached to said separable portions and main 1 tion and carried into tight sealing engagement by pressure within said chamber, the abutting surfaces of said sealing members terminating in the radial plane containingthe free edges of the rotor portions when in abutting relation.

2. In a centrifugal machine, the combination comprising a centrifugal rotor having a separating-chamber' defined by a base portion and a cover portion extending annularly about the axis of the rotorand mounted to be movable relative to each otheronly in an axial direction ,and normally retained in abutting relationship to prevent the discharge of material from said chamber, means for separatingsaid portions to afford provision for discharge of material fromsaid chamber, a deformable sealing member positively attached to each of said base and cover portions of said rotorand having one entire surface in contact'with a rigid part of said portions at the line of separation therebetween for sealing said chamber against the discharge of material between said portions when in abutting relationship, a second surface of said sealing members being exposed to the pressure within "said rotor by means of which the same are distorted into sealing engagement, the abutting surfaces of said sealing members terminating in the radial plane containing the free edges of the rotor portions when in abutting relation.

WIIMER H. BATH.

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