US2021346A - Sealing ring - Google Patents

Description

Nov. 19, 1935. F B, A LEN 2,021,346

SEALING RING Filed May 17, 1932 Snnentor Patented Nov. 19, 1935 UNITED STATES PATENT OFFICE SEALING RING Frank B. Allen, Lower Merion Township, Montgomery County, Pa., assignor to The Allen- Sherman-Hoff Company, Philadelphia, Pa., a corporation of Pennsylvania. 3

Application May 17, 1932, Serial No. 611,865 4 Claims. (Cl. 103-111) This invention relates to means for effecting centrifugal pumps; the provision of a sealing ring a seal between relatively moving parts, and more of thetype described which is self-adjusting, and particularly to sealing ringsfor centrifugal pumps self-compensating either because of variation in which are intended to be used for pumping fluids the spaces between the rotating element and sta- 5 containing abrasive or otherwise harmful subtionary element or because of wear of the reg S- I stances. tering surfaces; provision of a sealing ring and In the construction of centrifugal pumps for mounting therefor which will minimize wear upon handling liquids containing abrasive materials the ring 0 p the element Which-ii; engages such as ashes, sand or the like, it has been proby aut m y providing a fi m of clear Water posed to provide a supply of clear flushing water between these parts; the provision of an improved 10 to the pump and to cause this clear flushing mounting r t sealing r s f ntrifugal water to enter the main pumping. chamber P ps Which facilitates assembly d adju tthrough the clearance spaces between the romerit of the P p- I tating pump impeller and the stationary side The above and other objects of my invention plates of the pump, thus preventing the entry or will appear from e following d s ripti n of 15 abrasive material into these spaces and thereby sev al f ms thereof, reference being h d t maintaining the initial high efficiency of the the accompanying drawing in w pumping unit as well as materially reducing th Figure 1 is a side elevation, partly in section,

depreciation of certain parts of the pump which of a horizontal Centrifugal P p q ipped with would otherwise resultfrom the abrasive action my proved sealing devices. 20 of the material pumped. Figure 2 is an enlarged fragmentary sectional In practice it was found in order to produce v w o the sealing ring, u t a d in Figu e 1, the result above described, with a reasonably which is adapted to seal the joint between the small amount of sealing water, it was necessary lli p riphery of the impeller and he p p to maintain the clearances between the-rotating housing- 7 25 element and the stationary portions of the pump Figur 3 is e rs m t ry s ti na extremely low. Great difliculties resulted in that view of the sealing ri Shown in ure wh ch should the plane of rotation of the movin eleis particularly adapted to seal the joint between ment be not exactly true with the plane of the th in r p p ry o t i p r a d t pump various registering surfaces, the clearance bei ta etween would markedly vary. Then, it was either Figure 4 is w generally Similar to Figure necessary to largely increase the amount of seal- 3 b t illustrating a Sealing rin which is main-. ing water otherwise required, or the apparatu tained in sealing engagement with the impeller would fail to function and abrasive material would by spring means.

leak back into the clear water spaces. Even Figur 5 i a V Similar t Figure illus- 85 though the pump has been manufactured accutrating a modified form of sealing ring at the rately and functioned perfectly during, the life inner periphery of the impeller.

of the original impeller, yet after the first im- Figure 6 is a view similar to Figure 2 but illuspeller had worn out and'a second impeller was n i m fi o o Sealing ring for 40 installed, a very slight variation in that impeller joint at the outer periphery of the impeller. 40 from the first impellerv would result in the diffi- Figure '7 is a sectional view of the sealing ring culties above described. illustrated in Figure 3 and showing the grooves It is among the objects of my invention to prowhich assist in the formation of a lubricating vide means for definitely sealing these slip joints film between the sealing ring and pump.

or clearance spaces between the impeller and the Figure 8 is a view generally similar to Figure 2 45 pump housing which will permit of the flow of but illustrating a modified form of my improved clear flushing water into the pumping chamber, sealing ring. yet will automatically compensate for any reason- Figure '9 is a fragmentary view of sealing ring able variation in the distance between the stainstallation in which sealing rings of the general tionary portion of the pump and the rotating type shown in Figures 1 and 2 are mounted in element at any portion of its rotation, thus guarthe impeller. anteeing a constant and minimum clearance un- Referring now to Figure l, the centrifugal der allconditions of operation. pump illustrated is of the horizontal type and other objects of my invention are: the proviincludes a. shaft L at one end-of which is mounted sion of an improved type of sealing ring for the main impellerfz. The shaftl is suitably sup- I5 ported in bearings (not shown) and the impeller 2 rotates within the housing 4. The shaft sleeve 3 passes through a packing gland 341. An inlet 5 is adapted to conduct the fluid to be pumped into the housing I, where it is thrown out by the impeller blades 6 into the volute I from whence it passes into a suitable discharge pipe (not shown). The impeller 2 includes a plurality of radially extending main blades 6 which extend across between the discs 6 and 6. Auxiliary impeller blades Ill and II are formed or secured to the outside of the discs 6 and 9 and are adapted to rotate in the auxiliary pumping chambers l2 and I3 which are formed between the housing 4 and the discs 6 and 9. Auxiliary chamber I 2 is disposed on suction side of the pump, 1. e., the side of the pump adjacent the inlet pipe 5. Clear flushing water may be supplied to the auxiliary chambers l2 and I3 through the pipe I4 and its branches I 5 and I6.

To assist in preventing the flow of the fluid being pumped from the main pumping chamber or volute I back into the auxiliary chambers l2 and I3, I have provided the sealing rings I1 and I8. Grooves I! are formed in the side walls of the housing 4 and provide seats for the inwardly extending portions 20 of the sealing rings I1 and I6. The cross-sectional contour of the sealing rings l1 and I6 is best seen in Figure 2, which clearly shows the inner portion 20 of the ring seated in the groove l9 and the thickened outer portion 2| in position with its sealing face 22 bearing against the side of the impeller disc 8. The sealing rings l1 and i8 are preferably made of molded rubber or other suitably resilient and elastic material. To install them in position in the grooves l9 they are stretched over the lips l9 of the groove i9 and, before the-pump is assembled and the impeller placed in position, the rings assume the position shown in dotted lines in Figure 2. Thus, it will be seen that the inherent resiliency of the material of which the rings is constructed will tend to maintain the sealing face 22 in contact with the side of the impeller even though the face 22 may be considerably worn away during operation of the pump. When the pump is in operation a lubricating fllm of water will be formed between the face 22 of the ring and the impeller.

The housing 4 is so formed that an annular passage 23 connects the main pumping chamber with an enlarged annular chamber 24 disposed behind the sealing rings 11 and I8. With this construction it will be seen that when the clear flushing water pressure is increased by the auxiliary impeller blades Ill and II to a point greater than the pressure within the main pumping chamber 1, flushing water will flow through the joint between the face 22 of the sealing ring and the impeller discs I and 6. If, however, the pressure within the main pumping chamber becomes greater than that within the auxiliary chambers a pressure will be exerted on the outside surfaces 25 of the sealing rings l1 and I6 tending to force the sealing faces 22 into closer engagement with holes 21 which extend from the groove in which the ring 26 is seated into the auxiliary chamber I2. Thus, the pressure of the flushing liquid which enters the chamber [2 is applied to maintain tlm ring 26 in sealing position. The ring 26 is preferably formed with lips 26' which may be forced out into sealing contact with the walls of the groove by the flushing liquid pressure, thus preventing undesirable leakage past the sides of the sealing ring. Small grooves 26" are preferably cut in the contact face of the ring 26 to allow of lubrication between the ring and the rotating element.

The sealing rings illustrated in Figures 1, 2 and 3 which have been Just described are mounted in the housing in the pump, but, if desired, these rings may be mounted on the impeller and adapted to rotate therewith. Such an installation is shown in Figure 9. In this view the sealing ring 50 is supported in a suitable groove in the impeller side disc 5| and has a sealing face which engages the housing 52. This ring 56 is preferably cut away as at 53 so that the fluid pressure within the main pumping chamber may be effective to assist in holding the ring in sealing engagement with the housing. It will be understood that this ring is preferably so formed that its inherent resiliency also tends to hold it in sealing position. The ring 54 which is adapted to seal the Joint between the inner periphery of the impeller and the housing is generally similar to the ring 26 but is mounted in a suitable groove 55 in the impeller. The side of the sealing ring 54 opposite its sealing face is exposed to the pressure within the auxiliary flushing liquid chamber 56 through the hole or holes 51 and thus the pressure of the auxiliary water is effective to maintain the ring in sealing position.

In Figure 4 I have illustrated a. modifled arrangement in which the sealing ring 26a is disposed in a relatively deep groove in which are a plurality of springs 21' adapted to keep the ring in sealing contact with the inner periphery of the impeller 2. Rings of this type mounted in this manner may also be used in place of rings l1 and i6 to seal the Joint between the outer periphery of the impeller and the housing.

Figure 5 illustrates another modified form of sealing means in which an L-shaped sealing ring of reinforced rubber is employed. This ring includes an angular metallic reinforcing member 26 around whichis molded-a body of rubber or similar material 29. The reinforcing member 28 gives the desired stiffness to the ring, which is supported in position by being clamped between the portions 30 and 3| of the pump housing. In this instance, the sealing ring is adjusted to provide the proper clearance at the joint 32 between the inner periphery of the impeller disc 3 and the sealing face of the ring. By tightening or loosening the clamping bolts II the moldedrubber will compress or expand and the desired clearance at the Joint 32 may thus be readily obtained.

In Figure 6 I have illustrated a modified form of sealing ring which is particularly adapted to seal the joint between the outer periphery of the impeller 2 and the housing 4. This installation is generally similar to that shown in Figure 3 and includes a sealing ring 35 of rubber or similar flexible material, mounted in a groove 36 in the housing 4. The face 31 of the ring 35 is adapted to engage the impeller disc 8 adjacent its outer periphery. The groove 36 is connected to a passage or plurality of passages '39 extending from the groove 36 into the clear-water space l2.

Thus, communication is established between the clear-water chamber and the back side of the sealing ring 35 Fluid pressure within the clear.- water chamber will be applied to tend to flare the lips 38 outwardly tomaintain them in sealing contact with the sides of the groove 36 and exert a force on the sealing ring 35 tending to maintain the sealing face 31 in contact with the impeller 8. The operation of this form of my invention is substantially the same as that described with reference to Figure 3.

When the pressure of the flushing liquid within the chamber I2 is greater than that within the main pumping chamber the flushing liquid will be forced out through the lubricating grooves 35', thus lubricating the engaging surfaces and preventing the entry of harmful abrasive mate rial to the clearance spaces. Even if the pressure within the main pumping chamber should become greater than that within the auxiliary flushing water chamber the sealing ring 35 will be maintained in engagement with the impeller disc 8 and back flow of abrasive-containing liquid from the main pumping chamber into the auxiliary chamber will be largely prevented.

In Figure 8 I have illustrated another form of my sealing ring construction in which the sealing ring 40 is adapted to be maintained in sealing contact with the impeller 8 by means of the screws 4|. Lock nuts 42 are preferably provided to maintain the screws in the desired position. A number of screws may be disposed circumferentially around the housing and, by tightening or loosening these screws, the desired sealing engagement between the ring 40 and the impeller 8 will be obtained. A metallic backing ring 43 is preferably inserted between the inner ends of the screws 4| and the rubber sealing ring member.

From the above description it will be seen that my improved sealing ring construction provides an inexpensive and efficient means for preventing the entry of harmful foreign material into the clearance spaces between the impeller and the housing of a centrifugal pump and, although I have described in some detail the forms of my invention which are illustrated in the drawing, it will be understood that modifications and variations may be made without departing from the spirit of my invention. I do not, therefore, limit myself to the precise forms shown and described, but claim as my invention all embodiments thereof coming within the scope of the appended claims.

I claim:

1. A centrifugal pump comprising a pump casing having a volute, an impeller rotatable in the casing and spaced from the latter to form a clear water pressure chamber on one side thereof, said chamber having an annular outlet at its outer periphery into the volute, means for supplying clear water under pressure to said chamber, and sealing means for preventing entry of liquid into said chamber thru said annular outlet, said sealing means comprising an annular rubber ring mounted in an annular groove in the casing adjacent to the said chamber outlet and having a side face pressing thruout its circumferential length against the side of the impeller at all times with liquid sealing pressure to prevent passage of water thru the annular outlet into the chamber, said ring having a portion distorted laterally with respect to the remainder thereof by contact of the impeller with said face when the impeller and ring are in assembled position, and said distorted ing having a volute, an impeller rotatable in the casing and spaced from the latter to form clear water pressure chambers on opposite sides thereof, each of said chambershaving an annular'outlet at its outerperiphery into the volute, means for'supplying clear water under pressure to said chambers, and sealing means for preventing entry of liquid into said chambers thru said annular outlets, said sealing means comprising annular, rubber rings, mounted in annular grooves in the casing adjacent to the said chamber outlets, each ring having a side face pressing thruout its circumferential length against the side of the impeller at all times with liquid sealing pressure to prevent passage of water thru the annular outlets into the chambers, said rings having portions distorted laterally with respect to the remainder thereof by contact of the impeller with said faces when the impeller and distorted portions are in assembled position, said rings being movable away from the impeller only under the influence of water under pressure in the chambers to permit escape of such water between the rings and impeller, one of said chambers having an outlet opening into the suction side of the pump and means to impede escape of water from the chamber thru said outlet.

3. A centrifugal pump comprising a pump casing part having a volute, an impeller part rotatable in the casing part and spaced from the latter to form a clear water pressure chamber on one side thereof, said chamber having an annular outlet at its outer periphery into the volute, means for supplying clear water under pressure to said chamber, and sealing means for preventing entry of liquid into said-chamber thru said annular outlet, said sealing means consisting of a rubber member carried by one of the said pump parts and having an annular portion disposed adjacent to the said chamber outlet, said annular portion having a side face pressing thruout its circumferential length against the other said pump part at all times with liquid sealing pressure to prevent passage of water thru the annular outlet and into said chamber, said annular portion being distorted laterally with respect to the remainder of the rubber member by contact with the other said pump part when the said part and rubber member are in assembled position and said annular portion being movable away from the other said pump part only under the influence of water under pressure in the chamber to permit escape of such water between the member and the other said pump part.

4. A centrifugal pump comprising a pump casing part having a volute, an impeller part rotatable in the casing part and spaced from the latter to form clear water pressure chambers on opposite sides thereof, each of said chambers having an annular outlet at its outer periphery into the volute, means for supplying clear water under pressure to said chambers, and sealing means for preventing entry of liquid into said chambers thru said annular outlets, said sealing means consisting of rubber members, each member being separate and distinct from the other member, being carried by one of said pump parts and having an annular portion disposed in the casing adjacent to its respective chamber outlet, each annular portion having a side face pressing thruout its circumferential length against the other said pump part at all times with liquid sealing pressure to prevent passage of water thru the annular outlets into the chambers, each said annular portion being distorted laterally with respect to the remainder of the rubber member by contact with the other said pump part when in assembled relation therewith, and said annular portion being movable away from the other said pump part only under the influence of water un der pressure in its chamber to permit escape of such water between the member and the other said pump part, one of said chambers having an outlet opening into the suction side of the pump, and means to impede escape of the water thru the chamber of said outlet.

FRANK B. ALLEN.

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