US 2270054 A
Description (OCR text may contain errors)
Jan. 13, 1942. w. HOGAN 2,270,054
WATER SEAL FOR PUMPS Filed oct. 13. 1939 Patented Jan.. 13, 1942 WATER SEAL FOB PUMPS William Hogan, Augusta, Ga., aloignor to Georgia Iron Works, Augusta, Ga., a corporation of Georgia Application October 13, 1939, Serial No. 299,383
This invention relates to the art of fluid pumps and particularly to centrifugal pumps designed for handling liquids or liquids containing or conveying solids.
Although not restricted thereto, the invention finds an improved eld of use in sand pumps for dredging operations and the like. In centrifugal pumps employed for such operations considerable diliiculty is encountered in maintaining a proper seal in order to prevent recirculation of material in the pump. Such recirculation materially lowers the eiiiclency of the pump.
An object of this inventionA is to provide an improved seal for preventing recirculation in centrifugal pumps and the like. l
Another object isv to provide' an improved construction of liquid seal between the impeller of a centrifugal pump and its adjacent face plates.
A further object is to provide in a centrifugal pump, a novel construction of seal ring and manner of mounting the same.
Other objects will be readily apparent to those skilled in the art. While the present disclosure constitutes a preferred embodiment by which the invention is reduced to practice, itis to be understood that within the scope of the invention as claimed any desired variations and changes may be made in the structural details.
In the accompanying drawing, wherein like characters designate like parts throughout the several Views:
Figure l is a central vertical section through the centrifugal pump equipped with a seal in accordance with the invention.
Figure 2 is an enlarged fragmentary section illustrating the seal mounting detail oi Figure l.
Figure 3 is a fragmentary perspective of an inner seal ring employed in the pump.
Figure 4 is a fragmentary perspective view of an outer seal ring, also used. A
Figure 5 is a central vertical section through a pump and illustrating the disposition of sealing means on both the suction side and the hub side of the pump.
In detail the pump comprises a volute shell 6 within which is disposed an impeller 1 mounted on the end of the pump shaft 8 which has a bearing in the hub side plate 9; The suction side of the pump casing is closed in the usual manner by the suction side face plate III which is centrally apertured to provide the suction inlet II for the pump, the inlet being co-axial with the pump shaft.
On its suction side the impeller 1 has rigidly visis secured thereto, as by bolts I2 or by welding, a peripherally stepped annular plate I3 which rotates with the impeller within the annular chamber Il formed in the suction side face plate I0.
Approximately in axial alignment with the outer step I5 of the runner plate I3, the suction face plate III is formed with an undercut annular groove I8 which receives the base flange of a rubber sealing ring I1. The ring I1 has a snap action in its engagement with the seating groove I6 and it is securely retained in position by means-.of a metal lock ring I8. The lock ring I8 is snapped in place inside the rubber ring and seats upon the ledge formed vby the outer wall oi the groove I8. The outer peripheral face of the ring is tapered with respect to the seal ring I1, so that when the ring 'I8 is snapped in place the base of the sealing ring is wedged radially into the seating groove I6 and is thus rmly anchored in position on the hub side face plate III. The rubber sealing ring I1 extends inwardly over the periphery of the outer step I5 on the runner plate and has an internal bead I9 which bears against the periphery of the step under the tension imparted by the resiliency of the ring.
The inner step 20 of the runner plate I3 is 'chamfered as at 2l along its outer peripheral the ring bears against the cylindrical periphery ofthe step 2li, and the ring is anchored at its base by a retaining ring 24 which is reversely tapered with respect to the periphery of the base of theseal ring and which is snapped over the base of the seal ring to wedge the same firmly into the undercut groove 23. It will be apparent that by means of the snap rings I8 and 24 the outer seal ring and the inner seal ring are both rmly secured in position upon the suction side of the face plate of the pump and they are assembled on this plate before it is applied in position. This construction eliminates the necessity for the use of headed or screw threaded fastening elements as a means of anchoring the sealing rings in place.
While the outer and inner steps I5 and 20, respectively, are shown as bing provided by the plate I3 which is attached to the impeller,
these steps may be cast as integral portions of the impeller, Yif desired.
Figure 5 illustrates the construction of sealing ring assembly which is disposed both at the suction side and at the hub side of the pump. In order to prevent unnecessary repetition, and in view of the fact that details of sealing rings and retaining rings are identical at each side of the pump, the same reference characters have been employed to indicate identical parts at each side, the only difference being that at the respective sides of the pump the elements are reversed in position. I
The wall of the face plate I0 is provided with an aperture through which water or other liquid is supplied under pressure to the sealing chamber i4. The pressure at which the sealing medium is supplied to the chamber I4 is held at a higher point than the pressure existing within the pump. This results in a slight lifting of the outer seal ring bead IS which permits the sealing liquid, generally Water, to flow beneath the bead and lubricate its bearing on the step I5. The inner seal ring 22 is provided with an annular series of bleeder passages 26 through which the sealing liquid from the chamber Il is permitted to pass in small volume so that it becomes effective 1n lubricating the bearing between the ring 22 and the step 20 of the runner plate.
As in all such pumps, a definite clearance space 21 exists between the impeller 1 and the suction side face plate I0. A similar clearance space 28 exists between the impeller and the hub side face plate 9. As there is a high pressure in the volute 6 and a relatively lower pressure at the inlet Il, at which a definite suction exists,
there is a constant tendency for the material which the pump is handling to be forced back from the volute through the clearances 21 and 28 to the axial area of the impeller and thus to be recirculated with the consequent lowering of pump efnciency. In the present invention the higher pressure maintained within the chamber Il insures against collapse of the outer sealing ring l1 so that this ring effectively blocks off any passage of pump material radially inward along the passage between the impeller and the adjace'nt base plate. At the same time the chamber pressure maintains the ring 22 in sealing contact with the runner step 20 and only a small l tween the runner plate and the side portion of the sealing liquid is allowed to pass through the bleeder passages 2B. This small volume of the sealing liquid is adequate'to maintain lubrication. The chamfered portion 2i oi' the step 2li of the runner plate I3 eliminates'any possibility of the ring22. becoming pinched beface of the pump shell.
-An important feature of the invention resides ln the fact that the contacting faces of the outer sealing ring I1 and its retaining ring I8 are reversely tapered as are also the contacting faces of the inner sealing ring 22 and its retaining ring 24. `'I'his tapering results in a definite wedging action which crowds the base of each ring radially into its undercut holding groove. No projecting parts are exposed and the entire Aassembly is of simple rugged construction.
1. In a centrifugal pump, a face plate having an axial recess open to the inner side thereof, an undercut annular groove in a wall of the recess, a rubber sealing ring having a base flange seated in the groove, a resilient retaining ring overlying and in pressure engagement with the sealing ring in radial alignment with its base flange. and the contacting face of the retaining ring being beveled inwardly toward the sealing ring from the outer to the inner side faces of the retaining ring whereby to Wedge the base flange of the sealing ring radially into its groove, said resilient retaining ring constituting the sole means for holding said sealing ring in place.
2. In a centrifugal pump, a face plate having an axial recess opening to the inner side thereof, an undercut annular groove in a wall of the recess, a rubber sealing ring having a base flange seated in the groove, said ring having its surface opposite to the base flange beveled from the base of the ring away from the opposite flange bearing side of the ring, a resilient retaining ring overlying and in pressure engagement with the sealing ring in radial alignment with its base flange, and the contacting face of the retaining ring being reversely beveled with respect to the surface of the sealing ring whereby to wedge the base flange of the sealing ring radially into its groove, said resilient retaining ring constituting the sole means for holding said sealing ring in place.