US2955540A

US2955540A - Twin volute pump

Info

Publication number: US2955540A
Application number: US661656A
Authority: US
Inventors: Stefan S Pawlicki
Original assignee: Worthington Corp
Current assignee: Worthington Corp
Priority date: 1957-05-27
Filing date: 1957-05-27
Publication date: 1960-10-11
Anticipated expiration: 1977-10-11

Description

Oct. 11; 1960 s. s. PAWLICKI 2,955,540

TWIN VOLUTE PUMP F Filed May 27, 1957 2 Sheets-Sheet 1 I. VIIIIIIIJ FIG. 3 STEFAN SPAM/LICKI BYMM Oct. 11, 1960 s. s. PAWLICKI 2,955,540

TWIN VOLUTE PUMP Filed May 27. 1957 2 Sheets-Sheet 2 STEFAN s. PAWLICKI G- 6 INVENTOR BY MK?- I304 Unitt d St t Patent TWIN VOLUTE PUMP ington Corporation, Harrison, N. J., a corporation of Delaware Filed May 27, 1951, Ser. N0. 661,656 2 Claims. rat os-103) This invention relates to a centrifugal pump and in particular to a heavy walled twin volute pump provided with a separate splitter.

Twin volute pumps are generally used in applications requiring balanced radial forces and have beenmanufactured, heretofore, ,by casting the splitter element as "an integral part of the volute casing.

Pumps for high pressure application require 'thick walled casings, lb1 t the splitter should remain thin for hydraulic reasons, and cost of metal involved.

In order to effectively cast a twin volute pump casing, it is imperative that the thickness of the casing and the splitter be substantially equal; the equality in thickness being necessaryto prevent flaws in the casting, which flaws occur because of the unequal cooling time in a respective heavycasing and thin splitter cast integral therewith.

Casting the splitter as an integral part of the twin volute pump casing for a high pressure application presents other difiiculties; for example, twin volute pumps for high pressure applications undergo rigorous inspection tests such as a 'radiographic examination of the casting to determine whether there are flaws therein; searching through two separate layers of metal, as is the case in a twin volute having an integral splitter, not only detracts from the efficacy of the test, but also adds to the expense of such inspection.

In many cases the integral splitter fails during hydrostatic leak test. Failure results from the weakness in the casting at the point where the thin splitter joins the heavy walled volute.

Flaws detected during inspection of the casting are usually repaired, by a manner well known in the art. However, the flaws so detected, due to the inaccessibility of certain portions of the casing which results from the splitter being cast integral therewith, sometimes cannot be repaired and as a consequence the casting is discarded.

Some installations require volute pumps capable of contending with extremely high pressures and, in addition, require a higher finish on the inner periphery of the casing, which finish cannot be obtained by the usual casting methods nor can the inner periphery of the volute casing having a splitter integral therewith be finished by other well known methods in the art.

Accordingly, it is an object of the present invention to obviate the foregoing difliculties in the manufacture-of heavy walled twin volute pumps with the provision of a separate splitter element.

It is another object of this invention to locate the splitter accurately and connect it securely to the pump casing.

With these and other objects in view, as may appear from the accompanying specification, the invention consists of various features of construction and combination of parts, which will be-first described in connection with the accompanying drawings.

Figure l is a longitudinal section showing one form of splitter in operable position.

Ice.

Figure 2 is a section taken on line 22 of Figure 1.

Figure 3 is a longitudinal section showing a second construction embodying the principles of this invention.

Figure 4 is a section taken on line 4--4 of Figure 3.

Figure 5 is a longitudinal section of the invention specifically adapted for large pumps.

Figure 6 is a side elevation of Figure 5 partly broken away and showing the splitter in longitudinal section.-

Figure 7 is a perspective view of the splitter shown in Figure 5 Referring more particularly to the drawings, Figure 1 shows the preferred form of the heavy walled twin volute pump comprising a volute casing 1, characterized by its spiral or scroll-like conformation and further provided with heavy walls generally designated 2, in which an impeller 3 isrotatably mounted for pumping the liquid from the axial suction inlet 4 and discharging it through the radial discharge outlet 5.

In orderto balance the radial forces acting on the impeller 3 the volute casing 1 is divided into two channels, 6 and 7, in a manner well known in the art by the novel splitter element generally designated 8.

The volute casing 1 is provided with locator means such as an axial bore 9 and a crescent-shaped recess 10 for accommodating the splitter element 8 in operable position as is clearly shown in Figure 1 of the drawings' crescent-shaped protrusion 12 as an integral part of the' annular plate 11. I

In assembly the annular plate 11 of the splitter element: 8 is fixedly mounted in axial bore 9 by dowel pins 13 disposed through the beveled portion 14 of the annularplate 11 and in locking engagement with the walls adja cent the axial bore 9 so that the crescent-shaped pro-- trusion 12 abuts the base of the recess 10 to thereby divide the flow through the volute casing 1. 1 A modification of the splitter element 8 shown in: Figure 1 of the drawings is utilized in an applicatiom wherein the volute casing 1 is not provided with an axial' bore 9 adapted to accommodate the annular plate 11 of? splitter element 8.

The modified form shown in Figure 3 changes in par-' cent walls 22' and 23' of the volute casing 1' by bolt means 24'.

It will be noted that the splitter element 8' as the size of the pump is increased, tends to become cumbersome and diflicult to manage in the assembly thereof.

Accordingly, the volute casing 1" in Figure 5 is provided with locator means 30" as for example, ears 31" and 32 cast as an integral portion of the casing 1".

A separate splitter element 8" is formed by any known method of manufacture and preferably in three sections 33", 34" and 35" as is shown in Figure 7 of the drawings. By maintaining the width W" of the splitter B" relatively constant throughout the splitter 8", the fabrication and machining thereof are simple, economical operations.

In assembly, the splitter 8" is disposed adjacent the cars 31" and 32" and preferably connected thereto by any well known method in the art, as for example, by welding.

With the provision of a separate splitter element applicant discloses a twin volute pump that is characterized by the substantial minimization of the problems herein before mentioned. It will be understood that the invention. is not to be limited to the specific construction: or arrangement of parts shown, but that these may be, widely modified within the invention defined by the claims.

What is claimed is:

1. In a centrifugal pump of the twin volute type,, a heavy walled casing of unitary construction having, an inlet in a front wall thereof and a discharge outlet in a peripheral Wall. thereof, said casing having a rear wall axially spaced from. the wall having said inlet, impeller means in said casing for moving fluid from said inlet to, said discharge outlet, an independent splitter element for dividing the fluid into two substantially equal parts prior to the discharge thereof, said splitter element including a radially extending plate and having a crescent-shaped axially extending protrusion mounted thereon of constant width and of lesser wall thickness than said heavy walled.

casing, means for positioning said splitter within said 2. In a centrifugal pump of the twin volute type, a

heavy walled casing of unitary construction: having an inlet in a front wall thereof and a discharge outlet in a peripheral wall thereof, said casing having a rear wall axially spaced from the wall having said inlet, impeller' means in said casing for moving fluid from said inlet tosaid discharge outlet, an independent splitter element for dividing the fluid into two substantially equal parts prior to the discharge thereof, said splitter element including a radially extending plate and having a crescent-shaped axially extending protrusion mounted thereon of constant width and of lesser wall thickness than said heavy Walled casing, means for positioning said splitter within said casing, said means comprising a crescent-shaped recess in the wall of said casing having said inlet and engaging the end of the axially extending crescent-shaped protrusion, a shoulder in the wall of said axial bore engaging the peripheral edge of said radially extending plate, and means interconnecting said plate means to the casing whereby said crescent-shaped axially extending protrusion is maintained in operative position.

References Cited in the file of this patent UNITED STATES PATENTS 931,636 Neumann Aug. 17, 1909 1,047,663 Lawaczeck Dec. 17,1912 1,326,692 Rogatchoif Dec. 30, 1919 1 ,390,391 Skidmore Sept'. 13, 1921 1,745,854 Lawaczeck Feb. 4, 1930 1,940,455 Kilpela Dec. 19, 1933 2,112,386 Steele Mar. 29, 1938 2,157,002 Moss May'Z, 1939" 2,465,527 Goddard Mar. 29, 1949 2,653,546 Marlow Sept. 29, 1953 FOREIGN PATENTS 279,412 Germany Oct. 19, 1914 285,595 Germany July 7, 1915 407,568 Italy Nov. 3;.1944'