US1927543A - Sealing device - Google Patents

Description

Sepia, 19, 1933.

I F. B. DOYLE SEALING DEVICE Filed Feb. 3. 1932 Patented Sept. 19, 1933' OFF! SEALING DEVEGE Frank B. Doyle, Philiipsburg, N. 1., alllgnor a IngenolbBand Company, Jersey City, it. 3., a

corporation of New Jersey Application February 3, 1932. Serial No. 5903M Claims. (on. lea-n2) This invention relates to sealing devices, but more particularly to a sealing device for centrifugal pumps employing devices for counteracting I the unbalanced pressures to which the rotary ele- 5 ment or elements of the pump may be subjected.

One object of the invention is to effect an adequate seal between those portions of the balancing device which it is intended to subject to pressures of diflerent'values.

Another object is' to retain the structural advantages of pumpsot the type necessitating the use of auxiliary balancing devices and at the same time to materially increase their efllciency.

Other objects will be in part obvious and in part pointed out hereinafter.

The figure in the accompanying drawing is a sectional elevation of a centrifugal pump employing a balancing drum and having the invention appliedthereto.

"Referring more particularly to the drawing, the pump, which is designated in general by A, comprises the usual upper and lower casing sections B and C which may be secured together in any well known manner, as for instanceby bolts (not shown).

The pump selected for illustrative purposes is of the multistage type having initialand finalstage impellers D and E, respectively, mounted upon a shaft F to which they maybe secured 30 in any well known manner. The shaftF, which extends longitudinally through the pump, is journalled in stufling boxes G and H at the opposite ends of the casing sections. i One stufing box, as for instance that desigsections Band C, and the stufilng box H may,

as shown, be an integral part of a cover J which is arranged at the end of the casing sections B and C to form a closure therefor and to which it may be secured in any convenient manner.

At the side of the pump adjacent the impeller D is an inlet passage K which is defined by the casing. sections B and C. The passage K communicates directly with the inlet openings L of the passages in the. impeller D and the liquid passing through the impeller D is discharged into a discharge chamber 0 in the casing sections, whence it passes to the inlet openings? of the passages in the succeeding stage impeller E. The liquid flowing through the passages of the impeller E is discharged into a final discharge chamber Q encircling=the impeller E and passes from the discharge chamber Q through an outlet opening R to a desired destination.

In the arrangement shown-the impellers and nated G, may be an integral part of the casing E are so positioned that the inlet opening of each impeller is directed toward the inlet passage K. In such case, of course, the unbalanced pressures to which the rotary elements of the pump are subjected tend to thrust them axially in the w direction of the first-stage impeller. In order,- therefore, to counteract this tendency the shaft F is provided with a balancing device or drum S which is arranged adjacent the final-stage impeller E and interlockingly engages the shaft F, as by means of a key T.

The opposite ends of the balancing drum S constitute pressure areas U and V respectively which are subjected to pressures of'difierent values. In the present instance the area U, m which is the surface adjacent the final-stage impeller E, is subjected to the final discharge pressure of the pump since, as may be observed, the chamber W wherein the drum S lies is in constant communication with the discharge g5 chamber Q. l

, Encircling the balancing drum S and seated in the casing sections B and C, to which it may be aflixecl, is a ring X which forms a partition between the chamber W and a balancing chamber 30 Z- located in the end of the ring X and in the cover J. The balancing chamber Z is in direct communication with the inlet passage K through a conduit b, so that the balancing chamber 2 will be subjected to the same pressure which may 5 exist. in the inlet passage K.

The diameter of the balancing drum S and, therefore, the sizes of the pressure areas U and V are, of course, determined by the differential of the pressures which act. against the rotary mem- 9o bers of the pump and the direction in which it tends to movethem.

As may be readily appreciated, inpumps'of the type described and wherein balancing drums are employed as a means for preventing axial thrust of the rotary members it has been foundto bean exceedingly difiicult matter to efiecti'vely prevent communication between the final discharge and balancing chambers. In known structures of this type an objectionable degree of leakage takes place between the drum and the adjacent stationary element or elements, such as the ring X. Such leakage, of course, has the effect of-materially reducing the efficiency of the pump, and the resulting losses may be of such serious extent as to render a pump thus constructed undesirable for certain forms of usage.

In order to obviate the objectionable features outlined various expedients have been resorted to,

as for instance, arranging the impellersin backto-back relationship. Although the latter arrangement minimizes, to a considerable extent, the aforesaid difficulties, it adds greatly to the cost of manufacture as well as to the expense and difficulties of maintenance.

In view of the foregoing considerations it is contemplated to equip the pump with an effective sealing device which, in cooperation with the balancing drum, will prevent the undesirable leakage of fluid from the final discharge chamber of the pump into the balancing chamber. The sealing device applied for this purpose, and which is constructed in accordance with the practice of the invention, comprises a sealing member designated by c and which is arranged adjacent the pressure area V of the balancing drum S.

The sealing member 0 consists of a flange d having an end seating surface e to bear against a seating surface I on the end of the balancing drum S and which encircles the pressure area V. The flange (1 is of sufficiently smaller diameter than the interior of the ring X wherein it lies so that liquid in the chamber W may flow freely across the periphery of the flange d and may thus have free access to the opposite end of the flange d, which, in the present instance, constitutes an actuating surface g.

On one end of the sealing member 0 is an integral extension h of cylindrical shape which extends slidably into and is guided by an introverted flange 9' of the ring X. In the extension h is a key device, such as a screw k, which extends into a slot 0 in the flange 7' for holding the sealing member 0 against rotary movement and to prevent separation of the ring X and the sealing device during the operation of removing or inserting these elements from and into the casing.

As an additional precaution intended to prevent leakage of fluid from the chamber W to the chamber Z the flange 9' is provided with a recess p for the reception of an annular stationary packing member q which encircles the extension h which seat with one end against the actuating surface g. The springs it thus serve to compress the packing member q and also exert a pressure against the sealing element c to augment the pressure or pressures of the liquid for holding the member 0 against the balancing drum S.

The pressure of the springs u, as well as that acting against the actuating surface g, is further augmented by the pressure existing in the balancing chamber Z and acting against an actuating surface 0 on the free end of the extension h. The manner in which the sealing device serves to seal the final discharge chamber from the balancing chamber Z is as follows: During the operation of the pump a'portion of the fluid discharged from the final-stage impeller flows from the discharge chamber Q into the ring X and acts against the actuating surface g. The pressure I of such fluid will be augmented by the springs u nd by the fluid in'the balancin chamber The various pressures thusacting against the sealing member 0 will serve to hold it in the correct sealing relationship with the seating surface f and will effectively prevent the leakage of liquid from the flnal discharge chamber into the balancing chamber.

I claim:

1. In a centrifugal pump, the combination of a casing and a rotary member therein, a sealing member seating against the rotary member to effect a seal therebetween, an actuating surface on the sealing member subjected to discharge pressure from the pump for pressing the sealing member toward the rotary member, an extension on the sealing member slidably guided by the casing, spring means arranged about the extension and acting against the casing and the sealing means to augment the discharge pressure, and a stationary packing member'seated in the casing and being pressed into sealing relationship .with the extension by the spring.

2. In a centrifugal pump, the combination of a casing and a rotary member therein, a ring seated in the casing, a sealing member in the ring seating against the rotary member to effect a seal therebetween, an actuating surface on the 10C sealing member subjected to discharge pressure from the pump to press the sealing means toward the rotary member, an extension on the sealing member and being slidable in the casing, a packing member arranged about the extension and 10! being seated in the ring, spring-pressed means interposed between the packing and sealing members to augment the discharge pressure and to press the packing into sealing relationship with the extension, and means for interlockingly con- 11( necting the sealing member to the ring.

3. In a centrifugal pump, the combination of a casing and a rotary shaft, a balancing drum on the shaft to rotate therewith and being subjected on one side to discharge pressure and on the other 11! side to suction pressure, a sealing member seating against the balancing drum to prevent leakage of discharge pressure along. the drum, an extension on the'sealing member and being slidable in the casing, a packing member arranged about the extension and being seated in the casing, and spring-pressed means slidable on the extension and being arranged between the packing and sealing members to compress the packing member and to augment the suction pressure for holding 1 the sealing member in sealing relationship with the balancing drum.

4. In a centrifugal pump, the combination of a casing and a rotary shaft, a ring seated in the casing, a balancing drum on the shaft to rotate 3 therewith and having opposed differential pres sure areas, the larger of said pressure areas being exposed to discharge pressure and the smaller pressure area being exposed to suction pressure, a seating surface on the balancing drum encircling the smaller pressure area, a sealing member seating against the seating surface, and a plurality of actuating surfaces on the sealing member, one of said actuating surfaces being subjected to discharge pressure and another actuating surface being subjected to suction pressure for pressing the sealing member toward the seating surface, and means for interlockingly connecting the sealing member to the ring.

5. In a centrifugal pump, the combination of a casing and a rotary shaft, a balancing drum carried by the shaft and being exposed on one end to discharge pressure and on the other end to suction pressure, a sealing member slidable longitudinally of the balancing drum and seating thereagainst, a plurality of actuating surfaces on the sealing member, one of said actuating surfaces being exposed to discharge pressure and the other actuating surface being exposed to suction pressure for pressing the sealing member toward the balancing drum, a cylindrical extension on the sealing member and being slidable longitudinally in the casing, a packing member encircling

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