US2420401A - Centrifugal pump - Google Patents

Description

May 13, 1947. M. PROKOFIEFF CENTRIFUGAL PUMP Filed June 8, 1945 /9 1 n, K 22 BY mwawmn. [/V. I /MO/Zef/ ATTORNEY.

Patented May 13, 1947 UNITED STATES PATENT OFFICE 4 Claims.

This invention relates to improvements in centrifugal pumps.

One of the objects of this invention is to produce a centrifugal pump of high hydraulic efficiency at a minimum cost of construction.

Another object of my invention is to produce a centrifugal pump of high hydraulic efficiency in which the cost of operation will be minimized.

Another object of my invention is to produce a centrifugal pump fabricated from a series of separate parts, preferably composed of cold-rolled metal strips or plates. connected or joined to adjacent strips or plates or to other members to provldea complete pump.

To secure a maximum of hydraulic efficiency three factors are of great importance: (1) the elimination of jolts in the mass of passing liquid caused by bulges and inaccurate curvature of the vanes of the impeller and of the volute wall of the casing; (2) the reduction of friction of the flowing liquid upon the surfaces of the impeller vanes and upon the surface of the volute wall of the casing by providing finished surfaces and the perfecting of such surfaces to a maximum degree; and (3) minimizing the amount of eddy currents in the flow of liquid at the points of diversion of such flow and at the points of changes in the velocities and minimizing of impacts between such currents and the surfaces of the impeller vanes and volute wall of the casing.

In regard to the factor first mentioned, it will 'be understood that every bulge or inaccuracy of the curvature of the impeller vanes and of the casings produces, in operation, a jolt of a part of the mass of passing liquid. Such jolts absorb mechanical energy without any beneficial effect to the hydraulic performance at the discharge and a tremendous number of such jolts will absorb a considerable portion of such mechanical energy without beneficial efiect.

The second factor requires mathematically correct curvatures and the elimination of any imperfections in such surfaces, while in regard to the third factor, there is only one point to be considered, that is the discharge. My discharge arrangement consists of a discharge chamber having the shape of a segment of a circle and one end of the wall of this segmental discharge chamber is a continuation of the volute wall at the discharge side. In regard to the third factor, there is only one point to be considered and that is the method of discharge to avoid the eddy currents and impacts referred to.

With these and other objects in view, the invention comprises the combination of members and arrangement of parts so combined as to coact and cooperate with each other in the performance of the functions and the accomplishment of the results herein contemplated, and comprises in one of its adaptations the species or preferred form illustrated in the accompanying drawings, in which- Fig. l is a view in perspective of the peripheral wall of the casing combined with the discharge chamber;

Fig. 2 is a section through the pump parallel to the bottom substantially on the line 2-4 of Fig, 3, looking. in the direction of the arrows;

Fig. 3 is a, cross-section of the pump along the impeller shaft substantially on the line 3-3 of Fig. 2;

Fig. 4 is a view in :plan of a modified form of impeller vane; and

Fig. 5 is a view of an impeller vane similar to that shown in Fig, 2 embodying a hub member for the impeller shaft.

Referring now to these drawings, which illustrate a preferred embodiment of my invention, I employ for the construction both of the impeller and of the volute-casing cold rolled metal sheets, plates or strips and bend such sheets or plates of metal on templates to the mathematically correct curve. The use of such sheets, strips or plates of cold rolled metal enables the bending to be accomplished by conventional means and comprises a simple matter as it is a very simple matter to bend such a strip on a template, and obviously by providing a suitable template the mathematically correct curve for such cold rolled metal sheets, plates or strips may be obtained, and I am thus enabled to totally eliminate any possibility of bulges or inaccuracies of the curve and to solve all the problems referred to as factors numbered l and 2. Obviously the various connections or joints between the edges of the impeller vanes with the discs and at the hub and the connections or joints between the volute wall of the casing and the circular wall of the discharge chamber may be accomplished in any conventional manner that will not leave bulges and will enable the correct positioning of the vanes of the impeller in relation to the discs thereof, as well as the positioning of the end of the volute wall of the casting and the end of the wall of the discharge chamher.

I have found that by adopting this method of construction, the hydraulic efllciency of my pump will rise as high as to as against 50 to 75% of conventionally-constructed cast-metal pumps and the cost of construction will be reduced to as low as 10% to 15% of such cast metal pumps, thus providing a saving or economy of 85% to 90% or such cost. This saving is primarily due to the elimination of all the work of pattemmaking, molding, core-making, casting, machining, hand-finishing, etc.

The above statement of efliciency and saving in the cost of manufacture has been definitely proven by manufacture and the use of working models of a small capacity pump of about one H. P., and there is no doubt that the same or even better degrees of efilciency and savings may be accomplished in the manufacture of huge pumps for dredging, irrigation, dry docks, locks, etc.

Furthermore, there is no doubt that this method of construction in the same small scale of my one H. P. pump may be beneficially adapted for sections of multiple stage high pressure pumps of all sizes.

As to the third factor hereinabove referred to, the only point to be considered is the discharge. My proposed discharge construction consists of a discharge chamber having a wall of the shape a segment of a circle; one end of this segment 01 a circle merges with and comprises a continuation of the volute wall at the discharge side and the other end is connected with the volute casing at the very beginning of the curve at a very small angle. In this way the volute casing and the periphery of the discharge chamber will constitute one uninterrupted body.

Referring specifically to these drawings, l indicates the ump casing and 2 is the discharge chamber. As shown, the end wall 3 of the discharge chamber comprises a segmental part of a circle which is continuous and merges with a peripheral volutely-curved casing wall 4, and this volutely-curved wall-portion 4 extends to the connection or joint 5 between the said casing wall and the wall 3 of the discharge chamber. This connection 5 is positioned at the very beginning of the volute curve and the two walls extend from each other at a very small angle. In this way the peripheral volute-casing wall and the peripheral wall of the discharge chamber comprises a single uninterrupted and merged body. An impeller G is shown in Fig. 4 which comprises a pair of identical discs 1 and 8 and four identical vanes 9 which are, as aforesaid, bent into the proper curvature and each of the same has its inner hub end In abutting each other to provide a hub ll of polygonic or square configuration. The vanes 9 are suitably connected to the discs I and 3 and to each other at In to form the polygonic hub II which is mounted upon a shaft I2 with a square end l3 that fits into and loosely engages with the square polygonic hub H. The shaft i2 is mounted in a shaft holding block I! with a stufling box IE and the impeller and casing are mounted between side plates l6 and I1 and held in place by supplemental side plates l8 and IS. The impeller side-plate I1 is provided with an in-take aperture or hole 20 registering with an axially disposed intake hole 2| in the impeller disc 8. A base plate 22 is likewise provided with a hole 23 registering with the intake holes 20 and 2|.

In the embodiment shown, spacing washers 24 and 25 are positioned between the side plates and the discs I and 8 and, in the preferred form of my invention, the washer 25 is composed of rubber or like elastic material. The side plate I8 is provided with a circular discharge hole 28 registering with the discharge chamber 2 and laifllxtgigre or conduit 21 is fitted into the discharge In Fig. 4 I have shown a modified form of impeller vanes in which three vanes 8' are connected to each other at [0' to form a polygonal hub II".

In Fig. 5 I have shown another form or impeller vanes 8, the number and curvature of which are in all respects similar to those shown in Fig. 2. The vanes l in Fig. 5, however, are fastened at their inner ends. to each other and to a square hub member 28 provided with a hub aperture 28' within which the square end II of the shaft I2 is adapted to fit. In other respects the vanes shown in Fig. 5 are similar to those illustrated in Fig. 2.

By utilizing side or closure plates, each composed oi two layers of abutting fiat plates, I produce a construction in which each of the inner members l8 and I! of the flat side plates may have an opening or hole cut therein whose peripheral line is identical to the line of the peripheral wall of the volute housing for the impeller and discharge-chamber housing, and the combined volute housing-wall and dischargechamber housing-wall will fit into these opposed openings to provide a facile method of assembly as well as an edge reinforcement for said wall of said impeller and discharge-chamber housings. The side plates I6 and i1 abut and are securely fastened to the plates 3 and I9 and form closure plates for the said side wall of the impellerhousing and discharge-chamber. The bottom closure plate I! is provided with the inlet opening 20 while the upper closure plate It is provided with the circular outlet opening 26. As illustrated, the base plate also comprises a fiat plate 22 which abuts the bottom closure plate II. A base plate is desirable in embodiments of my invention for certain installations, but is not essential.

Having described my invention, I claim:

1. A centrifugal pump embodying, in combination, a pump casing having a housing composed of an impeller housing portion and a discharge chamber portion, said impeller housing portion having a volutely curved side wall and said discharge chamber portion having a side wall of arcuate conformation, an impeller mounted for rotation within said impeller housing portion, said two housing portions communicating with each other in the direction of flow from said impeller through a gradually expanding channel, and said side wall portions being formed integrally of one continuously curved imperforate strip of sheet metal having its opposite ends fastened together to provide a discharge chamber completely closed in said direction of flow from said impeller, and flat closure members at opposite ends of the entire side wall, one of which members is provided with an inlet opening at a positioning registering with said volute impeller housing portion and the other is provided with an outlet opening at a. position registering with said discharge-chamber housing portion.

2. A centrifugal pump embodying, in combination, a pump casing having a housing composed of an impeller housing portion and a discharge chamber portion, said impeller housing portion having a volutely curved side wall and said discharge chamber portion having a side wall of arcuate conformation, an impeller mounted for rotation within said impeller housing portion, said two housing portions communicating with each other in the direction of flow from said impeller through a gradually expanding channel, and said side wall portions being formed integrally of one continuously curved imperforate strip of sheet metal having its opposite ends fastened together housing portions communicating with each other in the direction of flow from said impeller through a gradually expanding channel, and said side wall portions being formed integrally of one conto provide a discharge chamber completely closed tinuously curved imperforate strip of sheet metal in said direction of flow from said impeller, and having its opposite ends fastened together to flat closure members at opposite ends of the enprovide a discharge chamber completely closed in tire side wall, one of which members is provided said direction of flow from said impeller, and with an inlet opening at a position registering flat closure members at opposite ends of the enwith said volute impeller housing portion and the tire side wall, one of which members is provided other is provided with an outlet opening at a with an inlet opening at a position registering position registering with said discharge-chamber with said volute impeller housing portion and housing portion, said closure members each being the other is provided with an outlet opening at a composed of outer and inner layers of abutting position registering with said discharge-chamber fiat plates, the inner layer having an opening housing portion, said volutely curved impeller therein whose peripheral line is identiacal to the housing portion beginning at a point closely adline of the periphery of the volute housing and jacent to the circumferential periphery of said discharge-chamber housing. impeller at one side thereof and gradually ex- 3. A centrifugal pump as claimed in claim 2 in panding as it extends completely around said which a circular discharge-opening is formed in impeller and merging at the opposite side of said the upper layer of the upper closure plates, said impeller with said discharge casing portion. discharge opening being located in axial align- IVAN M. PROKOFIEFF. ment with the arcuate side wall of the dischargechamber and having a discharge fitting inserted REFERENCES CITED therein and extending perpendiculaflyto the said The following references are of record in the upper layer of closure plates. me of this patent;

4. A centrifugal pump embodying, in combination, a pump casing having a housing composed UNITED STATES PATENTS of an impeller housing portion and a discharge Number Name Date chamber portion, said impeller housing portion 1,019,762 Cousans Mar. 12, 1912 having a volutely curved side wall and said dis- 1,149,904 Foster Aug. 10, 1915 charge chamber portion having a side wall of ar- 1,649,161 Foster Nov. 15, 1927 cuate conformation, an impeller mounted for rota- 1,758,062 Replogle May 13, 1930 tion within said impeller housing portion, said two 2,215,559 Morgan Sept. 24, 1940 Certificate of Correction Patent No. 2,420,401. May 13, 1947.

IVAN M. PROKOFIEFF It is hereby certified that errors appear in the numbered patent requiring correction as follows:

tinted specification of the above 8011mm 2, line 49, for casting read casing; column 4, line 61, claim 1, for positioning read position; column 5, line 16, claim 2, for identiacal read identical; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 29th day of July, A. D. 1947.

LESLIE FRAZER,

First Assistant Commissioner of Patents.

through a gradually expanding channel, and said side wall portions being formed integrally of one continuously curved imperforate strip of sheet metal having its opposite ends fastened together housing portions communicating with each other in the direction of flow from said impeller through a gradually expanding channel, and said side wall portions being formed integrally of one conto provide a discharge chamber completely closed tinuously curved imperforate strip of sheet metal in said direction of flow from said impeller, and having its opposite ends fastened together to flat closure members at opposite ends of the enprovide a discharge chamber completely closed in tire side wall, one of which members is provided said direction of flow from said impeller, and with an inlet opening at a position registering flat closure members at opposite ends of the enwith said volute impeller housing portion and the tire side wall, one of which members is provided other is provided with an outlet opening at a with an inlet opening at a position registering position registering with said discharge-chamber with said volute impeller housing portion and housing portion, said closure members each being the other is provided with an outlet opening at a composed of outer and inner layers of abutting position registering with said discharge-chamber fiat plates, the inner layer having an opening housing portion, said volutely curved impeller therein whose peripheral line is identiacal to the housing portion beginning at a point closely adline of the periphery of the volute housing and jacent to the circumferential periphery of said discharge-chamber housing. impeller at one side thereof and gradually ex- 3. A centrifugal pump as claimed in claim 2 in panding as it extends completely around said which a circular discharge-opening is formed in impeller and merging at the opposite side of said the upper layer of the upper closure plates, said impeller with said discharge casing portion. discharge opening being located in axial align- IVAN M. PROKOFIEFF. ment with the arcuate side wall of the dischargechamber and having a discharge fitting inserted REFERENCES CITED therein and extending perpendiculaflyto the said The following references are of record in the upper layer of closure plates. me of this patent;

4. A centrifugal pump embodying, in combination, a pump casing having a housing composed UNITED STATES PATENTS of an impeller housing portion and a discharge Number Name Date chamber portion, said impeller housing portion 1,019,762 Cousans Mar. 12, 1912 having a volutely curved side wall and said dis- 1,149,904 Foster Aug. 10, 1915 charge chamber portion having a side wall of ar- 1,649,161 Foster Nov. 15, 1927 cuate conformation, an impeller mounted for rota- 1,758,062 Replogle May 13, 1930 tion within said impeller housing portion, said two 2,215,559 Morgan Sept. 24, 1940 Certificate of Correction Patent No. 2,420,401. May 13, 1947.

IVAN M. PROKOFIEFF It is hereby certified that errors appear in the numbered patent requiring correction as follows:

tinted specification of the above 8011mm 2, line 49, for casting read casing; column 4, line 61, claim 1, for positioning read position; column 5, line 16, claim 2, for identiacal read identical; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 29th day of July, A. D. 1947.

LESLIE FRAZER,

First Assistant Commissioner of Patents.

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