FORM-2
THE PATENTS ACT, 1970 (39 of 1970)
&
THE PATENTS RULES, 2006
COMPLETE
Specification
(See Section 10 and Rule 13) SUCTION DRAFT TUBE FOR PUMPS
KIRLOSKAR BROTHERS LTD.
an Indian Company
of Udyog Bhavan, Tilak Road,
Pune 411 002, Maharashtra, India
Inventors:
l.GODBOLE VASANT
2. MTNCHEKAR SANDIP
3. CHOUGULE BABASO
4. SHINDE NILESH
The following specification particularly describes the invention and the manner in which it is to be
performed.

FIELD OF DISCLOSURE
The present disclosure relates to pumps used in transfer of fluids, more particularly, the present disclosure relates to a suction intake tube for guiding the fluid flow entering the pump.
BACKGROUND
A fluid pump is a device commonly used for raising or moving fluids from suction to pressure side. In fluid pumps, suction intake (draft) tubes are generally used for guiding the fluid flow. The suction intake tube facilitates a smooth flow of the fluids to the pump. In operation, a suction i.e. low pressure is created at the entrance of the intake tube for allowing the fluid to enter in the pump.
For pumping water from an open channel or a reservoir, the pump is installed in such manner that a suction inlet port is immersed in the water. A traditional suction intake tube as per the Hydraulic Institute Standard (HIS) is shown in the Figure 1 of the accompanying drawings, represented generally by the numeral 10. When the pump is operated, water is introduced in the pump through the suction inlet port 12 of the suction intake tube 10. The suction intake tube 10 has a height "h" and an outer diameter "d", where h is 1.28d. The radius of curvature "r" is 0.78d, and the length "1" of the intake tube 10 is 3.30d. The suction inlet port 12 has a height "hi" and width "w", where h1is 0.88d and w is 2.31d.
In this case, since the water around the suction inlet port 12 has a free surface, if the depth of suction inlet port 12 is reduced from the free surface of water, the water in the open channel flows at a large velocity, then an air entrained vortex (air entraining vortex) or a submerged vortex may be generated. The generation

of the air entrained vortex or the submerged vortex tends to cause vibration and noise which are detrimental to the operation of the pump. Thus, for keeping the minimum submergence of the suction inlet port 12, the suction intake tube 10 demands high excavation on-site. Therefore, the suction intake tube 10 occupies a large space. Furthermore, the suction intake tube 10 has no mechanism to aviode causes excessive pre-swirl of flow entering the pump, non-uniform spatial distribution of velocity at the entrance, and excess variation in velocity and swirl with time.
There is therefore felt a need for a suction intake tube for pumps that has reduced height, length, and width, thereby requiring lesser excavation on-site to maintain the minimum submergence. There is further a need for a suction intake tube for pumps that eliminates free surface, air entrained vortices, submerged vortices and pre-swirl of flow entering the pump, and provides uniform spatial distribution of velocity at the entrance with no variation in velocity and swirl with time.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative. -
Accordingly, an object of the present disclosure is to provide a suction intake tube for pumps that has comparatively reduced height, length and width, thereby requiring lesser excavation on-site to maintain the minimum submergence.

Another object of the present disclosure is to provide a suction intake tube for pumps that eliminates free surface, air entrained vortices, submerged vortices and pre-swirl of flow entering the pump.
Yet another object of the present disclosure is to provide a suction intake tube for pumps that provides uniform spatial distribution of velocity at the entrance with no variation in velocity and swirl with time.
Other objects and advantages of the present disclosure will be more apparent from the following description when read in conjunction with the accompanying figures, which are not intended to limit the scope of the present disclosure.
SUMMARY
In accordance with the present disclosure, there is provided a suction intake tube for conveying the flow of a fluid to a pump, said suction intake tube comprising:
a suction member for receiving a fluid flow, said suction member defining a housing having a central longitudinal axis, said suction member having a first open end defining a suction inlet port, a second closed end defining a semicircle on each side of said central longitudinal axis, a fluid discharge passage centrally positioned with respect to said central longitudinal axis proximal to said second closed end, a baffle plate positioned along said central longitudinal axis between said first open end and said fluid discharge passage, and a flow-path forming structure defining an hourglass-like frame positioned in said housing operatively below said fluid discharge passage for defining a flow path;
Said suction member diverging from said second closed end to said first open end and defining a first curvature with said fluid discharge passage, such that an operative surface of said flow-path forming structure defining a second curvature is disposed substantially concentrically around said first curvature

with a gap defined between said first curvature and said second curvature for defining said flow path.
Typically, in accordance with the present disclosure, the ratio of the outer diameter of said fluid discharge passage to the height of said suction intake tube is in the range of 1 : 1.05 to 1 : 1.25.
Preferably, in accordance with the present disclosure, the ratio of the outer diameter of said fluid discharge passage to the height of said first open end is in the range of 1 : 1.10 to 1 : 1.50.
Additionally, in accordance with the present disclosure, the ratio of the outer diameter of said fluid discharge passage to the height of said operative surface of said flow-path forming structure is in the range of 1 : 0.3 to 1 : 0.8.
Typically, in accordance with the present disclosure, the ratio of the outer diameter of said fluid discharge passage to the length of said suction intake tube from a vertical axis of said fluid discharge passage to said first open end is in the range of 1 : 2.2 to 1 : 3.2.
Preferably, in accordance with the present disclosure, the ratio of the outer diameter of said fluid discharge passage to the width of said suction intake tube is in the range of 1 : 2.5 to 1 : 3.5.
Typically, in accordance with the present disclosure, the ratio of the outer diameter of said fluid discharge passage to the radius of said first curvature is in the range of 1 : 0.3 to 1 : 0.45.

Additionally, in accordance with the present disclosure, the ratio of the outer diameter of said fluid discharge passage to the radius of said second curvature is in the range of 1 : 0.95 to 1 : 1.1.
Preferably, in accordance with the present disclosure, the ratio of the outer diameter of said fluid discharge passage to the radius of said semi-circle of said second closed end is in the range of 1 : 0.35 to 1 : 0.55.
Typically, in accordance with the present disclosure, the ratio of the outer diameter of said fluid discharge passage to the inner circumferential distance of said semi-circle of said second closed end from centre of said fluid discharge passage is in the range of 1 :1.15 to 1 : 1.35.
Preferably, in accordance with the present disclosure, the operative surfaces of said flow-path forming structure are inclined at an angle in the range of 25 to 50 ° with a vertical axis.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The disclosure will now be explained in relation to the non-limiting accompanying drawings, in which:
Figure 1 illustrates a side view and a top view of the conventional suction intake tube in accordance with the Hydraulic Institute Standard (HIS);
Figure 2 illustrates a side view and a top view of a preferred embodiment of the suction intake tube in accordance with the present disclosure;

Figures 3A & 3B illustrate a three-dimensional model of the preferred embodiment of the suction intake tube in accordance with the present disclosure;
Figures 4A & 4B illustrate a representation of the CFD analysis for the preferred embodiment of the suction intake tube in accordance with the present disclosure; and
Figure 5 illustrates a scale-down sump model of the preferred embodiment of the suction intake tube in accordance with the present disclosure.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The disclosure will now be described with reference to the accompanying drawings which do not limit the scope and ambit of the disclosure. The description provided is purely by way of example and illustration.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The present disclosure envisages a suction intake tube for conveying the flow of a fluid into a pump such as concrete volute pump and dry pit vertical turbine

pump. The suction intake tube of the present disclosure has reduced height, length and width as compared to the known suction intake tubes 10 (illustrated in Figure 1), thereby requiring lesser excavation on-site to maintain the minimum submergence. Also, the suction intake tube of the present disclosure eliminates free surface, air entrained vortices, submerged vortices and pre-swirl of flow entering the pump. Further, the suction intake tube provides uniform spatial distribution of velocity at the entrance with no variation in velocity and swirl with time.
Figure 2 of the accompanying drawings illustrates a preferred embodiment of the suction intake tube of the present disclosure; in which the suction intake tube is generally referenced by the numeral 100. The suction intake tube 100 comprises a suction member 102 which is disposed in an open channel or reservoir for receiving a fluid flow. The suction member 102 defines an interior void or housing 110 having a central longitudinal axis 116. The suction member 102 comprises a first open end 104 defining a suction inlet port and a second closed end 106. The second closed end 106 has a B-shape with a semi-circle on each side of the central longitudinal axis 116. A fluid discharge passage 112 is centrally positioned with respect to the central longitudinal axis 116 proximal to the second closed end 106. The suction member 102 further comprises a baffle plate 108 positioned along the central longitudinal axis 116 between the first open end 104 and the fluid discharge passage 112. The baffle plate 108 extends to a length before the first open end 104. The suction member 102 further comprises a flow-path forming structure 114 which forms an hourglass-like frame. The flow-path forming structure 114 is positioned in the housing 110 operatively below the fluid discharge passage 112 for defining a selective flow path. The suction member 102 diverges from the second closed end 106 towards the first open end 104 defining a first curvature 118 having radius Rl with the fluid discharge passage 112, such that an operative surface of the flow-path

forming structure 114 defining a second curvature 120 having radius R2 is disposed substantially concentrically around the first curvature 118 with a gap defined between the first curvature 118 and the second curvature 120 for forming the definitive flow path.
The suction intake tube has dimensions suitable to provide the inlet velocity or entry velocity as per the Hydraulic Institute Standard (HIS). In the preferred embodiment, the ratio of the outer diameter D of the fluid discharge passage 112 to the height H of the suction intake tube 102 is in the range of 1 : 1.05 to 1 : 1.25; the ratio of the outer diameter D of the fluid discharge passage 112 to the height HI of the first open end 104 is in the range of 1 : 1.10 to 1 : 1.50; the ratio of the outer diameter D of the fluid discharge passage 112 to the height H2 of the operative surface of the flow-path forming structure 114 is in the range of 1 : 0.3 to 1 : 0.8; the ratio of the outer diameter D of the fluid discharge passage 112 to the length L of the suction intake tube 102 from a vertical axis of the fluid discharge passage 112 to the first open end 104 is in the range of 1 : 2.2 to 1 : 3.2; the ratio of the outer diameter D of the fluid discharge passage 112 to the width W of the suction intake tube 102 is in the range of 1 : 2.5 to 1 : 3.5; the ratio of the outer diameter D of the fluid discharge passage 112 to the radius Rl of the first curvature 118 is in the range of 1 : 0.3 to 1 : 0.45; the ratio of the outer diameter D of the fluid discharge passage 112 to the radius R2 of the second curvature 120 is in the range of 1 : 0.95 to 1 : 1.1; the ratio of the outer diameter D of the fluid discharge passage 112 to the radius R4 of the semi-circle of the second closed end 106 is in the range of 1 : 0.35 to 1 : 0.55; the ratio of the outer diameter D of the fluid discharge passage 112 to the inner circumferential distance R3 of the semi-circle of the second closed end 106 from the centre of the fluid discharge passage 112 is in the range of 1 : 1.15 to 1 : 1.35; and the operative surfaces of the flow-path forming structure 114 are inclined at an angle in the range of 25 to 50 ° with the vertical axis. It should

however be noted that in the present disclosure the dimensions are not limited to any particular relation with the outlet diameter "D" of the fluid discharge passage 112.
Figures 3A & 3B of the accompanying drawings illustrate a three-dimensional model of the suction intake tube 100 of the present disclosure. The dimensions used in the model are represented herein as a multiple of the outer diameter D of the fluid discharge passage 112. The height H of the suction intake tube 102 is 1.08D, the height HI of the first open end 104 is 1.27D, the height H2 of the operative surface of the flow-path forming structure 114 is 0.52D, the length L of the suction intake tube 102 from a vertical axis of the fluid discharge passage 112 to the first open end 104 is 2.58D, and the width W of the suction intake tube 102 is 3.10D. Further, the radius Rl of the first curvature 118 is 0.39D, the radius R2 of the second curvature 120 is 1.03D, the inner circumferential distance R3 of the semi-circle of the second closed end 106 from centre of the fluid discharge passage 112 is 1.26D, and the radius R4 of the semi-circle of the second closed end 106 is 0.45D. The operative surfaces of the flow-path forming structure 114 are inclined at an angle of 35 ° with the vertical axis.
The given design of the suction intake tube 100 significantly reduces the length, width and height of the suction intake tube 100 as compared to the known suction intake tube 10 (shown in Figure 1). The height H of the suction intake tube 100 is reduced by about 19%, the length L of the suction intake tube 100 is reduced by about 28% and the overall dimension of the suction intake tube 100 is reduced by about 13%. Therefore, the suction intake tube 100 of the present disclosure requires comparatively less excavation on-site to maintain the minimum submergence. Also, the suction intake tube 100 of the present disclosure requires a smaller sized pump house as compared to the known intake tube 10.

Figures 4A & 4B of the accompanying drawings illustrate a representation of the CFD (computational fluid dynamics) analysis of the suction intake tube 100. The CFD analysis showed that the design of the suction intake tube 100 provides a streamline and uniform flow pattern. Swirl angles at the design flow and at 130% of the design flow are - 0.015° and 0.024° respectively, which is well within the acceptable limited of 5° by the HIS.
Figure 5 of the accompanying drawings illustrates a scale-down sump model of the suction intake tube 100. The scale-down sump model study was done as per the HIS standard. The ratio selected for sump model study was 1 : 10. A transparent model of the suction draft tube 100 was used for the sump model study. Color die was introduced in the flow path to observe turbulence. No turbulence was observed and the calculated actual swirl angle was 0.09°.
Based on the CFD analysis and the sump model study it is proved that the suction intake tube 100 meets the objects of the disclosure and can be used in fluid pumps like concrete or metallic volute pumps and dry pit vertical turbine pumps for preventing submerged vortices, air entrained vortices, free surface vortices and providing uniform spatial distribution of velocity at the intake with no variation in velocity and swirl with time.
TECHNICAL ADVANTAGES
The suction intake tube for pumps in accordance with the present disclosure described herein above has several technical advantages including but not limited to the realization of:
• the suction intake tube has a comparatively reduced height, length and width, thereby requiring lesser excavation on-site to maintain the minimum submergence;

• the suction intake tube eliminates free surface, air entrained vortices, submerged vortices and pre-swirl of flow entering the pump; and
• the suction intake tube provides a uniform spatial distribution of velocity at the entrance with no variation in the velocity and swirl with time.
Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression "at least" or "at least one" suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

We Claim:
1. A suction intake tube (100) for conveying the flow of a fluid to a pump,
said suction intake tube (100) comprising:
a suction member (102) for receiving a fluid flow, said suction member (102) defining a housing (110) having a central longitudinal axis (116), said suction member (102) having a first open end (104) defining a suction inlet port, a second closed end (106) defining a semi-circle on each side of said central longitudinal axis (116), a fluid discharge passage (112) centrally positioned with respect to said central longitudinal axis (116) proximal to said second closed end (106), a baffle plate (108) positioned along said central longitudinal axis (116) between said first open end (104) and said fluid discharge passage (112), and a flow-path forming structure (114) defining an hourglass-like frame positioned in said housing (110) operatively below said fluid discharge passage (112) for defining a flow path;
said suction member (102) diverging from said second closed end (106) to said first open end (104) and defining a first curvature (118) with said fluid discharge passage (112), such that an operative surface of said flow-path forming structure (114) defining a second curvature (120) is disposed substantially concentrically around said first curvature (118) with a gap defined between said first curvature (118) and said second curvature (120) for defining said flow path.
2. The suction intake tube as claimed in claim 1, wherein the ratio of the outer
diameter (D) of said fluid discharge passage (112) to the height (H) of said
suction intake tube (102) is in the range of 1 : 1.05 to 1 : 1.25.

3. The suction intake tube as claimed in claim 1, wherein the ratio of the outer diameter (D) of said fluid discharge passage (112) to the height (HI) of said first open end (104) is in the range of 1 : 1.10 to 1 : 1.50.
4. The suction intake tube as claimed in claim 1, wherein the ratio of the outer diameter (D) of said fluid discharge passage (112) to the height (H2) of said operative surface of said flow-path forming structure (114) is in the range of 1 : 0.3 to 1 : 0.8.
5. The suction intake tube as claimed in claim 1, wherein the ratio of the outer diameter (D) of said fluid discharge passage (112) to the length (L) of said suction intake tube (102) from a vertical axis of said fluid discharge passage (112) to said first open end (104) is in the range of 1 : 2.2 to 1 : 3.2.
6. The suction intake tube as claimed in claim 1, wherein the ratio of the outer diameter (D) of said fluid discharge passage (112) to the width (W) of said suction intake tube (102) is in the range of 1 : 2.5 to 1 : 3.5.
7. The suction intake tube as claimed in claim 1, wherein the ratio of the outer diameter (D) of said fluid discharge passage (112) to the radius (Rl) of said first curvature (118) is in the range of 1 : 0.3 to 1 : 0.45.
8. The suction intake tube as claimed in claim 1, wherein the ratio of the outer diameter (D) of said fluid discharge passage (112) to the radius (R2) of said second curvature (120) is in the range of 1 : 0.95 to 1 : 1.1.
9. The suction intake tube as claimed in claim 1, wherein the ratio of the outer diameter (D) of said fluid discharge passage (112) to the radius (R4) of said semi-circle of said second closed end (106) is in the range of 1 : 0.35 to 1 : 0.55,

10. The suction intake tube as claimed in claim 1, wherein the ratio of the outer
diameter (D) of said fluid discharge passage (112) to the inner circumferential
distance (R3) of said semi-circle of said second closed end (106) from centre of
said fluid discharge passage (112) is in the range of 1 : 1.15 to 1 : 1.35.
11. The suction intake tube as claimed in claim 1, wherein the operative
surfaces of said flow-path forming structure (114) are inclined at an angle in the
range of 25 to 50 ° with the vertical axis.