US3910715A

US3910715A - Side inlet means for centrifugal pumps

Info

Publication number: US3910715A
Application number: US374088A
Authority: US
Inventors: Shmariahu Yedidiah
Original assignee: Worthington Pump International Inc
Current assignee: Edison International Inc; Ingersoll Dresser Pump Co
Priority date: 1973-06-27
Filing date: 1973-06-27
Publication date: 1975-10-07
Anticipated expiration: 1992-10-07
Also published as: JPS5038102A; GB1475722A

Abstract

Side inlet means for a centrifugal pump has an inlet connected to the source of fluid to be pumped, and means forming a fluid flow passage extending through said side inlet means which defines, a diverging passage section, a shaped curved passage section, and a straight cylindrical passage section of varying length for delivering fluid to the suction eye of the impeller for the centrifugal pump having a velocity distribution which improves the efficiency thereof. Additionally, the side inlet means above described wherein the straight cylindrical passage section will have a predetermined length sufficient to permit operative association with inducer means for increasing the range of operation of the centrifugal pump.

Description

United States Patent 1191 Yedidiah 1 Oct. 7, 1975 SIDE INLET MEANS FOR CENTRIFUGAL PUMPS [75] Inventor: Shmariahu Yedidiah, West Orange,

[73] Assignee: Worthington Pump International,

Inc., Mountainside, NJ.

[22] Filed: June 27, 1973 [21] Appl. No.: 374,088

[52] US. Cl 415/182; 138/39 [51] Int. Cl. F04d 29/42; F04d 29/44 [58] Field of Search 415/182, 203, 206, 219, 415/204, 205; 417/360; 138/39 [56] 7 References Cited UNlTED STATES PATENTS 1,215,451 2/1917 White 60/696 2,303,949 12/1942 Nordell 2,433,156 12/1947 Pezzillom. 3,071,075 1/1963 Spring 3,734,649 5/1971 Sandy 415/143 FOREIGN PATENTS OR APPLICATIONS 727,357 6/1932 France 415/182 282,183 4/1952 Switzerland 415/203 1,089,234 3/1955 France 415/203 1,033,425 7/1953 France 1,035,385 8/1953 France 99,710 6/1923 Switzerland 138/39 Primary Examiner-William L. Freeh Assistant Examiner Louis J. Casaregola Attorney, Agent, or FirmDaniel H. Bobis [57] ABSTRACT Side inlet means for a centrifugal pump has an inlet connected to the source of fluid to be pumped, and means forming a fluid flow passage extending through said side inlet means which defines, a diverging passage section, a shaped curved passage section, and a straight cylindrical passage section of varying length for delivering fluid to the suction eye of the impeller for the centrifugal pump having a velocity distribution which improves the efficiency thereof.

Additionally, the side inlet means above described wherein the straight cylindrical passage section will have a predetermined length sufficient to permit operative association with inducer means for increasing the range of operation of the centrifugal pump.

6 Claims, 18 Drawing Figures U.S. Patent Oct. 7,1975 Sheet 1 of2 3,910,715

Sheet 2 of 2 3,910,715

US. Patent Oct. 7,1975

63 FIG.\8

mmn.

SIDE INLET MEANS FOR CENTRIFUGAL PUNIPS BACKGROUND OF THE INVENTION This invention relates generally to centrifugal pumps and more particularly to a side inlet means for guiding delivery of fluid to be pumped into the suction eye of the impeller for a centrifugal pump.

The efficiency of a centrifugal pump is affected by the characteristics of the fluid delivered into the suction eye of the impeller for the pump. More specifically, the velocity. distribution of the fluid as it flows into the suction eye of the impeller should be maintained as uniform as possible to prevent cavitation and energy losses during pumping of the fluid.

Where the-piping for passing fluid to be pumped leads directly into the suction inlet for the casing so that the fluid runs through a straight flow passage for a given length of piping; these desirable conditions for the fluid entering the suction eye of the impeller can be substantially achieved.

However, it is often desirable or necessary to connect pumps so that the fluid to be pumped is brought in through a side inlet means having an inlet in line with the piping arrangement for the system in which the pump is operating.

Such in line centrifugal pump arrangements are common because it permits the centrifugal pump to be positioned most advantageously in respect of the piping layoutfor the overall system. However, such side inlet I connection present problems in that it affects the function and the efficiency of the associate centrifugal pump connected thereto.

It has been found where the fluid to be pumped enters through a side inlet means that an adverse velocity distribution develops because of the frictional losses through the side inlet means and the turning forces acting on the fluid as it flows to the suction eye of the impeller for the centrifugal pump.

The known prior art side inlet means or connections deliver fluid to the suction eye of the impeller for the centrifugal pump with a velocity distribution which adversely affects the operation of the impeller in that they cause fluid to be delivered to the impeller at conditions less than the design requirements and thus limit the range and capacity of the given pump and reduce the efficiency thereof.

One. form of adverse velocity distribution of the known prior art side inlet means or connections is due to pre-rotation developed in the fluid entering the suction eye of the impeller. This is overcome in the prior art by various techniques. For example, a splitter fin or partition is inserted at a suitable point in the flow passage through the side inlet means which construction increascs the cost of the pump.

Another means of meeting the pro-rotation developed in the fluidentering the suction eye of the impeller is to redesign the impeller to match or meet the velocity distribution conditions of the fluid passing from the side inlet means to the suction eye of the impeller. This too is objectionable because it requires the manufacturer to tool up and inventory different types of impellers for centrifugal pumps as a function of the velocity distribution of the fluid entering the suction eye of the impeller from either a straight piping line or a side inlet means. t

The present invention overcomes these problems of the prior art devices by providing a side inlet means or connection in which the fluid flow passage therethrough is particularly designed to deliver fluid to be pumped to the suction eye of the impeller having a velocity distribution which produces a more efficient centrifugal pump operation and provides means to extend the range of operation of the pump.

This is accomplished by embodying between the inlet and the outlet for the fluid flow passage through the side inlet means, an entering diverging section in communication with the inlet which expands from the inlet area to up to three times that of the outlet area so that the fluid will initially slow down or reduce its velocity, a sized and shaped intermediate section which gives a nozzle effect thus causes the fluid to accelerate to a velocity equal to or greater than its initial velocity, and finally a straight cylindrical passage section just before the outlet through which the fluid to be pumped having a velocity distribution which is more uniform than that obtainable by the known prior art devices if passed to the suction eye of the impeller for the associate centrifugal pump communicating with the outlet end of the fluid flow passage in the side inlet means.

The acceleration of the fluid through the sized and shaped intermediate section produces the improved velocity distribution in the fluid passage to the suction eye of the impeller as above outlined.

SUMMARY OF THE INVENTION The present. invention provides an improved side inlet means for centrifugal pumps in which the fluid flow passage therein from the inlet to the outlet is characterized by a diverging passage section from the inlet which expands at the end thereof remote from the inlet to a cross-sectional area up to three times the area at the outlet and communicates with a sized and shaped curved passage section which narrows at the end remote from the point of communication with the diverging passage section to a cross-section diameter approximately equal to the diameter of the outlet and communicates with the straight cylindrical passage section which forms the outlet at the remote end thereof for the fluid flow passage.

The side inlet means may be a separate element or may be formed integral with the casing for the centrifugal pump and the straight cylindrical section of the fluid flow passage may have a predetermined length to accomodate an inducer means therein.

The construction of the present invention seeks to provide an improved side inlet means for centrifugal pumps which will deliver fluid to the suction eye of the impeller for the associated centrifugal pump at a velocity distribution which will improve the efficiency thereof.

It is another object of the present invention to provide a side inlet means for centrifugal pumps which includes a fluid flow passage therethrough having a straight cylindrical section immediately adjacent the outlet end of the fluid flow passage which coacts with the remaining sections of the fluid flow passage to provide an improved velocity distribution of the fluid delivered to the suction eye of the impeller for the associated centrifugal pump and whichmay have a predetermined length sufficient for operative relation with an inducer means ,for the given centrifugal pump.

These and other objects and advantages of the invention and the various features and details thereof are hereinafter more fully described in connection with the accompanying drawings in which:

FIG. 1 is a side elevation view of a motor driven pump with a side inlet means in accordance with the invention.

FIG. 2 is an enlarged view partly in vertical section of the pump and side inlet means of the motor driven pump shown in FIG. 1.

FIG. 3 is a side elevation of the side inlet means shown in FIG. 1.

FIG. 4 is a top elevational view of the side inlet means shown in FIG. 1.

FIG. 5 is an inlet end'view of the side inlet means shown in FIG. 1.

FIG. 6 is an outlet end view of the side inlet means shown in FIG. 1.

FIG. 7 is a horizontal section taken at line 77 of FIG. 3.

FIG. 8 is a section taken on line 88 of FIG. 7 illustrating the oval window in the fluid flow passage of the side inlet means looking towards the outlet end of the fluid flow passage.

FIG. 9 is aside elevation of the motor driven pump shown in FIG. 7 partly in vertical section showing an inducer element mounted in association with the straight cylindrical section of the fluid flow path through the side inlet connector.

FIG. 10 is a side elevation of a motor driven pump with an integral casing and side inlet means in accordance with the invention.

FIG. 11 is an enlarged side view partly in vertical section of the motor driven pump with an integral casing and side inlet means as shown in FIG. 10.

FIG. 12 is a side elevational view of the integral casing and side inlet means shown in FIG. 10.

FIG. 13 is a top elevational view of the integral casing and side inlet means shown in FIG, 10.

FIG. 14 is an inlet end view of the integral casing and side inlet means shown in FIG. 10.

FIG. 15 is an outlet view of the integral casing and side inlet means shown in FIG. 10.

FIG. 16 is a horizontal section taken at line 1616 of FIG. 11.

FIG. 17 is a horizontal section taken at line 1717 of FIG. 1 1.

FIG. 18 is a side elevational view of the motor driven pump shown in FIG. 10 partly in vertical section having an inducer element mounted therein in association with the straight cylindrical section of the side inlet means section of the integral casing and side inlet means.

Referring to the drawings, FIG. 1 shows a motor driven centrifugal pump 10 with a side inlet means 11 in accordance with the invention having an inlet 12 and outlet 13.

About the inlet 12 flange means 14 is provided for connecting the side inlet means to a suitable conduit (not shown) communicating with the source of the fluid to be pumped. Similarly, about the outlet 13, flange means 15 is provided having a plurality of circumferentially disposed openings 16 through which threaded means 17 extend for connection to bores 18 provided in a boss 19 formed about the suction inlet 20 in the casing 21 of the motor driven pump 10.

The casing 21 includes the conventional pumping chamber 22 in communication with the suction inlet 20 and a discharge outlet 23 for passing the fluid being pumped to any suitable point of use.

Mounted in the pumping chamber 22 is an impeller means 24 which is connected and rotatable with the shaft 25 driven by the motor 26.

The impeller 24 is disposed in the pumping chamber 22 so that the suction eye 27 is in direct communication with the suction inlet 20 formed in the casing 21.

As can be readily seen from FIG. 2 of the drawings, the outlet 13 of the side inlet means 11 is in direct alignment with the suction inlet 20 and the suction eye 27 of the impeller. Thus, fluid delivered to the suction inlet 20 will flow directly into the suction eye 27 of the impeller 23 for the centrifugal pump 10.

Fluid to be pumped is delivered from the inlet 12 to the outlet 13 of the side inlet means 11 by a fluid flow passage 30 therein having a particular design hereinafter more fully described.

When the motor driven centrifugal pump 10 is in operation the fluid to be pumped enters the inlet 12 and flows through the fluid flow passage 30 to the outlet 13. By reason of the alignment of the outlet 13 with the suction inlet 20 for the casing 21 and with the suction eye 27 for the impeller 24, fluid will pass immediately into the rotating impeller 24, where'it is discharged through the pumping chamber 22 to the discharge outlet 23 for the centrifugal pump 10.

The operation of motor driven centrifugal pumps of the type shown in the present invention is so well understood by those skilled in the pumping art that a further description of the illustrated pump is not deemed necessary for the purposes of the present invention which as noted above provides for the advantageous results in design and arrangement by reason of the side inlet means and the fluid flow passage 30 therein now to be more particularly described by reference to FIGS. 2 to 8 of the drawings.

SIDE INLET MEANS Thus, referring to FIGS. 2 to 8, the side inlet means shown is an elongated cylindrical or tubular member having convoluted curved portions between the inlet 12 and the outlet 13 thereon.

Inlet 12 of the side inlet means 11 in assembled position is disposed in a plane above the outlet 13 substantially in alignment with the discharged outlet 23.

Inlet 12 will be a spaced distance from casing 21 to permit the motor driven centrifugal pump 10 to be connected so that the inlet 12 and the discharge outlet 23 will be in alignment with the piping conduit (not shown) for the pumping system in which the in line motor driven centrifugal pump will be used. This particular configuration is illustrated because it is a desirable arrangement for a pumping system. It will be understood, however, that where the side inlet means 11 is a separate element as shown in FIGS. 1 to 8 of the drawings, that is may be positioned so that the inlet for the side inlet means 1 1 is at any desired angle to the discharge outlet 23 of the centrifugal pump 10 without departing from the scope of the present invention.

The side inlet means 11 has a descending section 31, a curved section 32 and a straight cylindrical section 33. These sections of the side inlet means contain the corresponding passage sections of the fluid flow passage 30 which includes, diverging passage section 34, the shaped curved passage section 35 and the straight cylindrical passage section 36. These

passage sections

34, 35 and 36 of the fluid flow passage 30 communicate with each other in the order indicated from the inlet 12 to the outlet 13. Thus, the inlet communicates with the diverging passage section 34 which section is in communication with the shaped curved passage section 35, in turn in communication with the straight cylindrical passage section 36 which communicates with the outlet 13.

By reference to FIG. 2, the outlet 13 and the straight cylindrical passage section 36 are shown in alignment with each other and as having their centerline on the longitudinal or vertical line of the motor driven centrifugal pump 10.

Further, the outlet 13 and the straight cylindrical passage section 36 are shown as having a diameter D. This diameter is the reference standard from which the remaining portions of the fluid flow passage 30 are designed. It may be equal to the diameter of the suction eye 27 of the impeller 24 as illustrated at FIG. 2 or may have a diameter differing from the preferred form illustrated up to greater or less than the diameter of the suction eye 27 without departing from the scope of the present invention.

In addition, FIG. 2 shows that the straight cylindrical passage section 36 of the fluid flow passage 30 may have a predetermined length B. This predetermined length will be a function of the length of the inducer 40 shown in assembled position in FIG. 8 of the drawings. However, except for this operative relation, the length of the straight cylindrical passage section 36 may be varied to provide operating results.

FIGS. 2 and 7 show that the inlet 12 will have a diameter A which may be slightly smaller, equal to or slightly larger than the diameter D of the outlet 13. It should not be less than 0.75 of the diameter D and generally will be in the ratio 0.9 to 1.25 of the diameter D.

The diverging section 34 which communicates at one end with the inlet 12 expands to a plane of communication with the shaped curved section preferably in the form of an oval window or opening 37 which has a width CW up to three times the diameter D and a height CH not less than 30% of the diameter of A whereby the total cross-sectional area of the oval window or opening 37 will be in a range from 1.50 to 2.25 times the cross-section area of the outlet 13 and preferably will have a total cross-section area in the range from 1.75 to 2.00 times the cross-sectional area of the outlet 13. It will be understood that the oval window or opening 37 is not an absolute limitation. Other shapes could be used without departing from the scope of the present invention.

From the point where the shaped curved passage section 35 communicates at the plane of communication or oval window 37 with the diverging passage section 34, it is curved on a radius substantially in range from 0.75 to 1.50 of the diameter D of outlet 13. This radius is drawn on the centerline of the side inlet means 1 1 at a point in alignment with the side of the straight cylindrical passage section 36 closest to the inlet 12 for the side inlet means 11, as is clearly shown in FIGS. 4 and 7 of the drawings.

At the end remote from the oval window or opening 37 the shaped curved passage section 35 narrows to a cross-sectional area having a diameter substantially equal to the diameter D so that the axial section thereof at the point which communicates with the straight cylindrical passage section 36 is a smooth, uniform and simple bend.

Thus, there is provided a flow passage 30 from the inlet 12 to the outlet 13 of the side inlet means which has a specific defined shape for accomplishing the advantageous and desired result of providing fluid flow to the suction eye 22 of the impeller 24 of centrifugal pump 10 having a substantially uniform velocity distribution.

COMBINED CASING AND SIDE INLET CONNECTOR In FIGS. 10 to 18 of the drawings, an alternate form of motor driven centrifugal pump is shown having a side inlet means in accordance with the present invention combined with the casing of the pump portion of the motor driven centrifugal pump.

Thus, FIGS. 10 and 11 show a motor driven, in line, centrifugal pump 50 with a combined casing and side inlet means 51 having an inlet 52 and a discharge outlet 53 as is shown in FIG. 11 of the drawings.

It will be understood that while an in line centrifugal pump is illustrated that the combined casing and side inlet means can have the inlet and discharge outlet for the centrifugal pump at various angles to each other other than the in line arrangement as shown without departing from the scope of the present invention.

About the inlet 52, a flange means 54 is provided for connecting the combined casing and side inlet means 51 to a suitable conduit (not shown) communicating with the source of fluid to be pumped. Similarly, about the discharge outlet 53 a flange means 55 is provided with is connected to suitable means (not shown) for passing the pumped fluid from the motor driven, in line, centrifugal pump 50 to any suitable point of use.

The combined casing and side inlet means 51 includes a casing section 51a and a side inlet means section 51b and at the point 56 therein forms both a suction inlet for the casing section 51a and an outlet for the side inlet section 51b which is referred to hereinafter as the suction inlet/outlet 56 in the combined casing and side inlet means 51.

In the casing section 51a, a conventional pumping chamber 57 is formed which communicates with the suction inlet/outlet S6 to receive fluid to be pumped from the side inlet means section 51b. Pumping chamber 57 also communicates with the discharge outlet 53 for discharging fluid from the centrifugal pump 50.

Mounted in the pumping chamber 57 is an impeller means 58 which is connected and rotatable with a shaft 59 driven by the motor 60.

Impeller 58 is mounted in the pumping chamber 57 so that the suction eye 61 is in direct communication with the suction inlet/outlet 56 formed at the point where the casing section 51a and side inlet means section 51b are joined into integral unit form so that suction inlet/outlet 56 in the combined casing and side inlet means 51 is thus in direct alignment with the suction eye 61 of the impeller 58.

Inlet 52 is in communication with the suction inlet/- outlet 57 by means of a connecting passage 62.

When the motor driven, in line, centrifugal pump 50 is in operation, the fluid to be pumped enters the inlet 52, and flows through the connecting passage 62 to the suction inlet/outlet 56. By reason of the alignment of the suction inlet/outlet 56 with the suction eye 61 of the impeller 58, fluid will pass immediately into the rotating impeller 58 where it is discharged through pumping chamber 57 into the communicating discharge outlet 53 to the point of use.

The operation of motor driven centrifugal pumps of the type shown in the present invention are so well understood by those skilled in the art that further description of the illustrated pump is not deemed necessary for the purposes of the present invention.

As in the form of the invention above described for FIGS. 1 to 8 of the drawings, the connecting fluid flow passage 62 in the side inlet means section 51b has a particular design to increase the efficiency of the pump operation and also to permit inducer means generally designated 63 to be added to the impeller as shown in FIG. 18 so as to increase the range of operation of the pump particularly at lower load and at lower Net Positive Suction Heads (N.P.S.H.) as will now be described.

COMBINDED CASING AND SIDE INLET Thus, referring to FIGS. 10 to 17 of the drawings, the combined casing and side inlet means 51 shows that the side inlet means section 51b having the connecting fluid flow passage 62 is an elongated cylindrical or tubular member having convoluted curved portions between the inlet 52 and the suction inlet/outlet 56 of the combined casing and side inlet 51.

It will be noted that the inlet 52 of the combined casing and side inlet 51 in assembled position is disposed in a plane above the suction inlet/outlet 56 and will be in substantial alignment with the discharge outlet 53. This construction permits the motor driven centrifugal pump 50 to be placed in alignment with the piping (not shown) for the pumping system in which the in line, motor driven centrifugal pump will be used, all of which is clearly shown in FIGS. 10, 11, l2, 13, 14, 15, 16, I7 and 18 of the drawings.

Referring to FIG. 1 l, the side inlet means section 51b of the combined casing and side inlet means 51 is shown as forming a descending section 64, a shaped curved section 65 and a straight cylindrical section 66. These portions are on the side inlet means section 51b, and they contain the corresponding diverging passage section 67, the shaped curved passage section 68 and the straight cylindrical passage section 69 of the connecting fluid flow passage 62. These

passage sections

67, 68 and 69 of the connecting fluid flow passage 62 communicates with each other in the same order as stated from the inlet 52 to the suction inlet/outlet 56 in the combined casing and side inlet means 51.

Thus, the inlet 52 communicates with the diverging passage section 67 which communicates with the shaped curved passage section 68 which in turn communicates with the straight cylindrical passage section 69 in communication with the suction inlet/outlet 56.

By reference to FIGS. 11, 16 and 17, it can be seen that the suction inlet/outlet 56 and the straight passage section 69 are in alignment with each other and have their centerline on the longitudinal or vertical line of the motor driven centrifugal pump 50.

Further, the suction outlet/inlet 56 and the straight passage section 69 are shown as having a diameter D substantially equal to the suction eye 61 of the impeller 58 in a same manner as above described for the form of the invention shown in FIGS. 1 to 8 of the drawings.

As in the first form of the invention, this diameter is the reference standard against which the remaining sections of the connecting fluid flow passage 62 are designed. The diameter D of the outlet/inlet 56 however can be greater or less than the diameter of the suction eye 61 for impeller 58 by as much as 20%. It will, however, be the reference diameter and not the diameter of the suction eye for the impeller although in the preferred embodiment it is considered best to have a diameter substantially the same as the suction eye.

In addition, the straight passage section 69 of the connecting fluid flow passage 62 is shown in FIG. 1 1 as having a predetermined length B which may be a function of the length of inducer means 63 as is shown in FIG. 18 of the drawings.

FIGS. 11, 15 and 16 of the drawings show that the inlet 52 for the combined casing and side inlet 51 has a diameter A which may be slightly smaller, equal to or slightly larger than the diameter D of the suction outlet- /inlet 56 and generally will be in the ratio between 0.9 to 1.25 of the diameter of the suction inlet/outlet 56. The diverging section 67 which communicates at one end with the inlet 12 expands to an oval window which has a width CW up to three times the diameter D and a height CH less than A to provide a total crosssectional area in the preferred range of approximately 1.75 to 2.00 times the cross-sectional area of the suction outlet/inlet 56.

From the point where the shaped curved passage section 68 communicates with the oval window or opening 70 of the diverging section 67, it is curved on a radius substantially equal to the diameter D of the suction outlet/inlet 56. The radius being drawn on the centerline of the diverging section 67 closest to the inlet side of the straight cylindrical passage section 69 in the same manner as shown in FIG. 7 for the form of the side inlet means shown in FIGS. 1 to 7 of the drawings.

At the end remote from the oval window 70, the shaped curved section 68 narrows to the cylindrical diameter D so that the axial section at the point which communicates with the straight cylindrical passage section 69 is a smooth uniform and simple bend.

Thus, as in the first form of the invention described there is provided a connecting fluid flow passage from the inlet 52 to the suction outlet/inlet 57 which has a specific defined shape for accomplishing the advantageous and desired results of providing fluid flow at the suction outlet/inlet 56 which has a substantially uniform velocity distribution.

It is noted that the preferred dimensional ranges of the form of the invention shown in FIGS. 10 to 17 are identical with those for the form of the invention shown in FIGS. 1 to 8 of the drawings. It will be understood that the general dimensional ranges indicated for the first form of the invention are equally applicable to this integral casing and side inlet means form of the invention.

Whether the side inlet means is formed as an independent element or integrally with the casing, it is the shape and design of the fluid flow passage through the side inlet means that accomplishes the advantageous results of the present invention, in that it guides and acts on the fluid to be pumped as it passes therethrough so that at the point when the fluid to be pumped is delivered into the suction eye of the impeller for the centrifugal pump, it will have a substantially uniform velocity distribution.

While the foregoing description illustrates various preferred embodiments in accordance with the present invention, it will be appreciated that certain changes and modifications may be made in the structure of these disclosed arrangements without departing from the spirit and scope of the invention and that the same is defined by the claims as hereinafter set forth.

What is claimed is:

1. A side inlet means for centrifugal pumps comprising:

a. first means forming an inlet at one end of the side inlet means,

b. second means formingan outlet at theother end of the side inlet means and said outlet having a given cross-sectional flow area,

c. means forming a fluid flow passage through said side inlet means including,

1. a descending seciton forming the portion of said fluid flow passage in communication with the inlet, said descending section expanding to provide at the end of said portion of .the fluid flow passage remote from the inlet remote from the inlet end a substantially elliptical cross-sectional flow area having a major axis and a minor axis and the flow area therethrough being greater than but not more than three times the cross-sectional flow area of the outlet,

2. a curved section sized at one end to fit the expanded end of the descending section, the major axis of the substantially elliptical cross-sectional flow area being parallel to the axis of curvature of said curved section and the minor axis transverse thereto,

3. said curved section to form the intermediate portion of said fluid flow passage and contracting at the end remote from the end thereof connected to the descending section to provide at said remote end of the intermediate portion of the fluid flow passage a cross-sectional flow area substantially equal to the cross-sectional flow area of the outlet whereby the velocity of the fluid flow through the descending section is. reduced before it enters the curved section and the velocity of the fluid is accelerated after it leaves the curved section, and

4. a straight cylindrical section between the contracted end of the curved section and the outlet forming the portion of the fluid flow passage connecting the intermediate portion with the outlet, and

d. means for connecting the side inlet means into assembled position for use,

2. A side inlet means for centrifugal pumps comprising:

a. first means forming an inlet at one end of the side inlet means,

b. second means forming an outlet at the other end of the side inlet means and said outlet having a given cross-sectional flow area,

c. means forming a fluid flow passage through said side inlet means including,

1. a descending section forming the portion of said fluid flow passage in communication with the in let, said descending section expanding at the end of said portion of the fluid flow passage remote from the inlet end,

2. curved section sized at one end to fit the expanded end of the descending section and forming the intermediate portion of said fluid flow passage,

3. a straight cylindrical section between the end of the curved section and the outlet forming the portion of the fluid flow passage connecting the intermediate portion with the outlet.

d. the cross sectional flow area of the fluid flow passage at the plane of connection bet-ween the descending section and the curved section has an oval shape and is in a range between 1.75 to 2.0 times the cross-sectional flow area of the outlet for the side inlet means.

e. said curved section contracting at the end remote from the end thereof connected to the descending section to provide at said end of the intermediate portion of the fluid flow passage a cross-sectional flow area substantially equal to the cross-sectional flow area of the outlet whereby the velocity of the fluid through the descending section is reduced before it enters the curved section and the velocity of the fluid is accelerated after it leaves the curved section, and i f. means for connecting the side inlet means into assembled position for use.

3. In a side inlet means as claimed in claim 1 wherein,

the curved section is widest at its plane of connection with the descending section and the intermediate fluid flow passage through the curved section is formed by an arcuate section,

b. said arcuate section formed on a radius of curvature parallel to a vertical plane through the intermediate portion of the fluid flow passage substantially about the point of intersection of the vertical plane through the intermediate portion with the upper section of the plane of connection between the descending section and curved section,

c. the radius of curvature for said arcuate annular section between 0.9 to 1.1 of the diameter of the fluid flow area through the outlet, and

(1. said arcuate section also having a second radius of curvature substantially normal to the vertical plane through the intermediate portion of the fluid flow passage substantially about the point of intersection of the vertical plane through said intermediate portion with the centerline of the fluid flow passage at the plane of connection between the descending section and the curved section.

4. In a centrifugal pump,

a. .casing means forming a pumping chamber having a suction inlet of predetermine diameter and a discharge outlet,

b. impeller means mounted for rotating in said pumping chamber and having a suction eye in communication with the suction inlet for said casing,

c. a side inlet means forming a fluid flow passage therein having an inlet at one end and an oulet at the end remote therefrom,

(1. means connecting said side inlet means to said casing whereby the outlet thereof will be in communication with said suction inlet for the casing, and said outlet having a given flow area substantially equal to that of the suction inlet,

e. said side inlet means including,

1. a descending section forming a portion of said fluid flow passage in communication with the inlet for the side inlet means,

2. said descending section expanding to provide at the end of said portion of the fluid flow passage remote from the inlet end a substantially oval cross-sectional flow area having a major axis and a minor axis and the flow area therethrough being greater than but not not more than three times the cross-sectional flow area of the outlet,

3. a curved section forming the intermediate portion of said fluid flow passage sized and shaped at one end to connect to the expanded end of the descending section so that the major axis of the oval cross-sectional flow area is parallel to the axis of curvature of said curved section and the minor axis normal thereto,

4. said curved section contracting at the end remote from the end thereof connected to the descending section to provide at said end of the intermediate portion of the fluid flow passage a cross-sectional flow area substantially equal to the cross-sectional flow area of the outlet whereby the velocity of the fluid flowing through the descending section is reduced before it enters the curved section and the velocity of the fluid is accelerated as it leaves the curved section, and

5. a straight cylindrical section connected between the end of the curved section remote from the descending section and the outlet for the side inlet means to form the portion of the fluid flow passage connecting the intermediate portion with the outlet to deliver fluid at substantially uniform average velocity into the suction eye of the impeller.

5. In a centrifugal pump,

a. casing means forming a pumping chamber having a suction inlet of predetermined diameter and a discharge outlet,

b. impeller means mounted for rotation in said pumping chamber and having a suction eye in communication with the suction inlet for said casing.

c. a side inlet means forming a fluid flow passage therein having an inlet at one end and an outlet at the end remote therefrom,

e. said side inlet means including,

l. a descending section forming a portion of said flow passage in communication with the inlet for the side inlet means,

2. said descending section expanding to provide at the end of said portion of the fluid flow passage remote from the inlet end an oval cross-sectional flow area,

3. a curved section sized and shaped at one end to connect to the expanded end of the descending section and forming the intermediate portion of said fluid flow passage,

4. a straight cylindrical section connected between the end of the curved section remote from the descending section and the outlet for the side inlet means to form the portion of the fluid flow passage connecting the intermediate portion with the outlet to deliver fluid at substantially uniform average velocity into the suction eye of the impellor,

f. the cross sectional flow area of the flulid flow passage at the plane of connection between the descending section and the curved section is in a range between 1.75 to 2.0 times the cross-sectional flow area of the outlet for the side inlet means, and

g. said curved section contracting at the end remote from the end thereof connected to the descending section to provide at said end of the intermediate portion of the fluid flow passage a cross-sectional flow area substantially equal to the cross-sectional flow area of the outlet whereby the velocity of the fluid flowing through the descending section is reduced before it enters the curved section and the velocity of the fluid is accelerated as it leaves the curved section.

6. In a centrifugal pump as claimed in claim 4 wherein,

a. said centrifugal pump includes inducer means,

b. said straight cylindrical passage section having a predetermined length and a cross-sectional flow area substantially equal to said outlet for the side inlet means to permit the inducer means for said centrifugal pump to extend in the centerline thereof at least a portion of the length of said cylindrical section.

Claims

1. A side inlet means for centrifugal pumps comprising: a. first means forming an inlet at one end of the side inlet means, b. second means forming an outlet at the other end of the side inlet means and said outlet having a given cross-sectional flow area, c. means forming a fluid flow passage through said side inlet means including, 1. a descending seciton forming the portion of said fluid flow passage in communication with the inlet, said descending section expanding to provide at the end of said portion of the fluid flow passage remote from the inlet remote from the inlet end a substantially elliptical cross-sectional flow area having a major axis and a minor axis and the flow area therethrough being greater than but not more than three times the cross-sectional flow area of the outlet, 2. a curved section sized at one end to fit the expanded end of the descending section, the major axis of the substantially elliptical cross-sectional flow area being parallel to the axis of curvature of said curved section and the minor axis transverse thereto, 3. said curved section to form the intermediate portion of said fluid flow passage and contracting at the end remote from the end thereof connected to the descending section to provide at said remote end of the intermediate portion of the fluid flow passage a cross-sectional flow area substantially equal to the cross-sectional flow area of the outlet whereby the velocity of the fluid flow through the descending section is reduced before it enters the curved section and the velocity of the fluid is accelerated after it leaves the curved section, and 4. a straight cylindrical section between the contracted end of the curved section and the outlet forming the portion of the fluid flow passage connecting the intermediate portion with the outlet, and d. means for connecting the side inlet means into assembled position for use.

2. A side inlet means for centrifugal pumps comprising: a. first means forming an inlet at one end of the side inlet means, b. second means forming an outlet at the other end of the side inlet means and said outlet having a given cross-sectional flow area, c. means forming a fluid flow passage through said side inlet means including,

3. a straight cylindrical section between the end of the curved section and the outlet forming the portion of the fluid flow passage connecting the intermediate portion with the outlet. d. the cross sectional flow area of the fluid flow passage at the plane of connection between the descending section and the curved section has an oval shape and is in a range between 1.75 to 2.0 times the cross-sectional flow area of the outlet for the side inlet means. e. said curved section contracting at the end remote from the end thereof connected to the descending section to provide at said end of the intermediate portion of the fluid Flow passage a cross-sectional flow area substantially equal to the cross-sectional flow area of the outlet whereby the velocity of the fluid through the descending section is reduced before it enters the curved section and the velocity of the fluid is accelerated after it leaves the curved section, and f. means for connecting the side inlet means into assembled position for use.

3. said curved section to form the intermediate portion of said fluid flow passage and contracting at the end remote from the end thereof connected to the descending section to provide at said remote end of the intermediate portion of the fluid flow passage a cross-sectional flow area substantially equal to the cross-sectional flow area of the outlet whereby the velocity of the fluid flow through the descending section is reduced before it enters the curved section and the velocity of the fluid is accelerated after it leaves the curved section, and

3. In a side inlet means as claimed in claim 1 wherein, the curved section is widest at its plane of connection with the descending section and the intermediate fluid flow passage through the curved section is formed by an arcuate section, b. said arcuate section formed on a radius of curvature parallel to a vertical plane through the intermediate portion of the fluid flow passage substantially about the point of intersection of the vertical plane through the intermediate portion with the upper section of the plane of connection between the descending section and curved section, c. the radius of curvature for said arcuate annular section between 0.9 to 1.1 of the diameter of the fluid flow area through the outlet, and d. said arcuate section also having a second radius of curvature substantially normal to the vertical plane through the intermediate portion of the fluid flow passage substantially about the point of intersection of the vertical plane through said intermediate portion with the centerline of the fluid flow passage at the plane of connection between the descending section and the curved section.

4. In a centrifugal pump, a. casing means forming a pumping chamber having a suction inlet of predetermine diameter and a discharge outlet, b. impeller means mounted for rotating in said pumping chamber and having a suction eye in communication with the suction inlet for said casing, c. a side inlet means forming a fluid flow passage therein having an inlet at one end and an oulet at the end remote therefrom, d. means connecting said side inlet means to said casing whereby the outlet thereof will be in communication with said suction inlet for the casing, and said outlet having a given flow area substantially equal to that of the suction inlet, e. said side inlet means including,

4. a straight cylindrical section connected between the end of the curved section remote from the descending section and the outlet for the side inlet means to form the portion of the fluid flow passage connecting the intermediate portion with the outlet to deliver fluid at substantially uniform average velocity into the suction eye of the impellor, f. the cross sectional flow area of the flulid flow passage at the plane of connection between the descending section and the curved section is in a range between 1.75 to 2.0 times the cross-sectional flow area of the outlet for the side inlet means, and g. said curved section contracting at the end remote from the end thereof connected to the descending section to provide at said end of the intermediate portion of the fluid flow passage a cross-sectional flow area substantially equal to the cross-sectional flow area of the outlet whereby the velocity of the fluid flowing through the descending section is reduced before it enters the curved section and the velocity of the fluid is accelerated as it leaves the curved section.

4. a straight cylindrical section between the contracted end of the curved section and the outlet forming the portion of the fluid flow passage connecting the intermediate portion with the outlet, and d. means for connecting the side inlet means into assembled position for use.

5. In a centrifugal pump, a. casing means forming a pumping chamber having a suction inlet of predetermined diameter and a discharge outlet, b. impeller means mounted for rotation in said pumping chamber and having a suction eye in communication with the suction inlet for said casing. c. a side inlet means forming a fluid flow passage therein having an inlet at one end and an outlet at the end remote therefrom, d. means connecting said side inlet means to said casing whereby the outlet thereof will be in communication with said suction inlet for the casing, and said outlet having a given flow area substantially equal to that of the suction inlet, e. said side inlet means including,

6. In a centrifugal pump as claimed in claim 4 wherein, a. said centrifugal pump includes inducer means, b. said straight cylindrical passage section having a predetermined length and a cross-sectional flow area substantially equal to said outlet for the side inlet means to permit the inducer means for said centrifugal pump to extend in the centerline thereof at least a portion of the length of said cylindrical section.