FIELD

The present disclosure relates to the field of mechanical engineering. In particular, the present disclosure relates to multistage pumps. BACKGROUND

Pumps comprising two or more than two impellers are known as multistage pumps. In conventional multistage pumps, impellers are connected in series and mounted on a shaft extending along the length of the multistage pump. Each impeller represents a stage of the multistage pump. The liquid to be pressurized enters the multistage pump via a suction conduit into a suction compartment, where an impeller delivers a pressurized liquid to a subsequent compartment. In this manner, the liquid is pressurized and fed to the next compartment, and the pressurized liquid of the desired pressure is then discharged at the end compartment of the multistage pump. However, a problem associated with the conventional pump is that, at the end compartment, the pressure of the liquid is so high that a high pressure mechanical seal is needed to be installed to avoid leakage of the high pressure liquid. The failure of the high pressure mechanical seal is hazardous as the leakage of the pressurized liquid may cause damage. Moreover, the requirement of the high pressure mechanical seal at the end stage of the series of the multistage pump also impacts the interchangeability of the seals, because at the opposite end of the multistage pump, which receives the liquid to be pumped in the suction compartment, a relatively low pressure mechanical seal is needed.

Hence, in order to overcome the above mentioned drawbacks, there is need for a multistage pump that does not involve the use of a high pressure mechanical seal at the end compartment of the multistage pump.

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. An object of the present disclosure is to provide a multistage pump that has a configuration which eliminates the usage of high pressure seals.

Another object of the present disclosure is to provide a multistage pump that has a configuration which reduces the inventory of spare components for the seals. Yet another object of the present disclosure is to provide a multistage pump that has a safe operation.

Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.

SUMMARY The present disclosure envisages a multistage pump. The multistage pump comprises a housing defined by a first operative end and a second operative end, wherein the housing has a compartmentalized configuration. A shaft is disposed within the housing such that the shaft extends along the length of the housing. A plurality of impellers is mounted on the shaft such that each impeller of the plurality of impellers is disposed in each compartment of the housing. A suction compartment is defined within the housing adjacent the first operative end, wherein the suction compartment is configured to receive the liquid to be pressurized. An end compartment is defined within the housing adjacent the second operative end, wherein the end compartment is in fluid communication with the suction compartment and is configured to receive pressurized liquid from the suction compartment to further increase the pressure of the pressurized liquid. A plurality of intermediate compartments is defined within the housing operatively between the suction compartment and the end compartment, wherein at least one of the intermediate compartments is in fluid communication with at least one of the suction compartment and the end compartment. The plurality of intermediate compartments is also in fluid communication with each other, wherein the pressurized liquid is received within at least one intermediate compartment and transferred to at least one other intermediate compartment for further increasing the pressure thereof, whereafter the pressurized liquid is discharged from any one of the intermediate compartments.

In an embodiment, the multistage pump further includes a pair of low pressure seals mounted on the shaft at the first and second operative ends of the housing, wherein the fluid communication of the suction compartment with the end compartment eliminates the need of using a high pressure seal.

In an embodiment, the intermediate compartment, from which the pressurized liquid is discharged, is located substantially centrally within the housing. Preferably, the liquid is water.

In an embodiment, the pump has five impellers mounted on the shaft and located within five separate compartments within the housing. The five separate compartments include the suction compartment, the end compartment, and three intermediate compartments configured operatively between the suction compartment and the end compartment. In an embodiment, the discharge of the pump is facilitated via the medial intermediate compartment of the three intermediate compartments.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWING

A multistage pump of the present disclosure, will now be described with the help of the non- limiting accompanying drawing, in which: Fig. 1 illustrates a schematic diagram of a conventional multistage pump; and

Fig. 2 illustrates a schematic diagram of a multistage pump, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION

Fig. 1 illustrates a schematic diagram of a conventional multistage pump. As seen in Fig. 1, the conventional multistage pump 100 (hereinafter referred to as the conventional pump 100) comprises a housing 102. A shaft 104 is disposed within the housing 102 such that the shaft 104 extends along the length of the housing 102 and protrudes out of a first and second operative ends 102X, 102Yof the housing 102. The shaft 104 is configured to drive and support a plurality of impellers 106 A - 106F. The number of impellers represents the number of stages of the multistage pump. The housing 102 has a compartmentalized configuration. An impeller 106A - 106F is disposed within each compartment, thereby defining a stage of the conventional pump 100. A suction conduit 108 is configured on a suction compartment 102A. The suction conduit 108 facilitates the entry of the liquid to be pressurized inside the suction compartment 102A. The liquid is pressurized in the suction compartment 102A via the impeller 106A, and the pressurized liquid is then fed to a subsequent intermediate compartment 102B via a feeder conduit 11 OA. In a similar manner, the liquid is pressurized in the intermediate compartments 102B - 102D and fed to the subsequent compartment via the feeder conduits HOB - HOC. The pressurized liquid is then fed from the intermediate compartment 102D to an end compartment 102F via a feeder conduit HOD. The pressurized liquid is then fed from the end compartment 102F to the intermediate compartment 106E via the feeder conduit 110E and discharged therefrom via an outlet conduit 112.

The conventional pump 100 further comprises a low pressure mechanical seal 114 disposed on the shaft 104 adjacent to the first operative end 102X of the housing 102 to prevent the leakage of the liquid from the suction compartment 102A of the housing 102, since the pressure of the liquid is relatively low as compared with at the pressure of the liquid in the end compartment. Similarly, the conventional pump 100 further comprises a high pressure mechanical seal 116 disposed on the shaft 104, adjacent to the second operative 102Y of the housing 102, to prevent the leakage of the pressurized liquid from the end compartment 102F of the housing 102, since the pressure of the liquid is very high in the end compartment 102F. However, if the high pressure mechanical seal 116 fails, the pressurized liquid will leak out. The use of a low pressure mechanical seal at one end of the housing, and the use of a high pressure mechanical seal at the other end of the housing impacts the interchangeability of seals.

The present disclosure envisages a multistage pump that overcomes the above mentioned drawbacks associated with the conventional pump. The present disclosure envisages a multistage pump. The multistage pump comprises a housing defined by a first operative end and a second operative end, wherein the housing has a compartmentalized configuration. A shaft is disposed within the housing such that the shaft extends along the length of the housing. A plurality of impellers is mounted on the shaft such that each impeller of the plurality of impellers is disposed in each compartment of the housing. A suction compartment is defined within the housing adjacent the first operative end, wherein the suction compartment is configured to receive the liquid to be pressurized. An end compartment is defined within the housing adjacent the second operative end, wherein the end compartment is in fluid communication with the suction compartment and is configured to receive pressurized liquid from the suction compartment to further increase the pressure of the pressurized liquid. A plurality of intermediate compartments is defined within the housing operatively between the suction compartment and the end compartment, wherein at least one of the intermediate compartments is in fluid communication with at least one of the suction compartment and the end compartment. The plurality of intermediate compartments is also in fluid communication with each other, wherein the pressurized liquid is received within at least one intermediate compartment and transferred to at least one other intermediate compartment for further increasing the pressure thereof, whereafter the pressurized liquid is discharged from any one of the intermediate compartments. The multistage pump further includes a pair of low pressure seals mounted on the shaft at the first and second operative ends of the housing, wherein the fluid communication of the suction compartment with the end compartment eliminates the need of using a high pressure seal.

Fig. 2 illustrates a schematic diagram of a multistage pump 200 (also referred to as pump 200), in accordance with an embodiment of the present disclosure. As seen in Fig. 2, the multistage pump 200 comprises a housing 202 defined by a first operative end 202X and a second operative end 202Y. A shaft 204 is disposed within the housing 202 such that the shaft 204 extends along the length of the housing 202 and protrudes out of the first and second operative ends 202X, 202Yof the housing 202. The shaft 204 is configured to drive and support a plurality of impellers 206A-206E. The housing 202 has a compartmentalized configuration. An impeller is disposed within each compartment, thereby defining a stage of the multistage pump 200. In the present embodiment, the multistage pump includes five impellers. However, the number of the impellers is not limited to five and can be any number greater than two. The pump 200 has five impellers mounted on the shaft and located within five separate compartments within the housing. The five separate compartments include the suction compartment, the end compartment, and three intermediate compartments configured operatively between the suction compartment and the end compartment. A suction conduit 208 is configured on a suction compartment 202A and facilitates the entry of the liquid to be pressurized inside the suction compartment 202A. The liquid is pressurized in the suction compartment 202A via the impeller 206A, and the pressurized liquid is then fed directly to the compartment at the opposite operative end, which defines an end compartment 202E of the multistage pump 200, via a conduit 210. From the end compartment 202E, where the pressurized liquid is further pressurized via the impeller 206E, the pressurized liquid is fed to the intermediate compartment 202D via the feeder conduit 212A. From the intermediate compartment 202D, where pressurized liquid is further pressurized via the impeller 206D, the pressurized liquid is then fed directly to the intermediate compartment 202B via the feeder conduit 212B, where it is pressurized further via the impeller 206B. The pressurized liquid is then transferred from the intermediate compartment 202B to the intermediate compartment 202C via the feeder conduit 212C. The intermediate compartment 202C acts as the outlet compartment and the pressurized liquid is discharged therefrom via an outlet conduit 214. In an embodiment, the intermediate compartment, from which the pressurized liquid is discharged, is located substantially centrally within the housing. Preferably, the liquid is water.

The multistage pump 200 further comprises low pressure mechanical seals 216 A, 216B disposed on the shaft 204 adjacent to, both, the first and the second operative ends 202X, 202Y of the housing 202 to secure the compartments 202A to 202F and avoid the leakage of the liquid therefrom. Since the liquid is being transferred from the suction compartment 202A directly to the end compartment 202E that is disposed at an opposite operative end thereof, the pressure of the liquid at the end compartment 202E is such that a low pressure mechanical seal can be used to prevent the leakage of the liquid therefrom. Also, if the low pressure seal 216B fails, the pressure of the leaked liquid is not very high. As such, the operation of the multistage pump 200 of the present disclosure is safe. Moreover, since both the seals are low pressure mechanical seals 216A, 216B, the seals are interchangeable, thereby reducing the inventory of spare components. The present disclosure is further illustrated herein below with the help of the following examples. The examples used herein are intended merely to facilitate an understanding of the ways in which the embodiments herein may be practiced and to further enable those skilled in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the disclosure. An experimental analysis was conducted on the multistage pump 200 of the present disclosure. In the experiment, the differential head, suction pressure, and pressure acting on the seal adjacent the second operative end of the multistage pump 200 were observed for various flow rates. The observations of the experiment as tabulated in Table 1. TABLE 1

Due to the configuration of the multistage pump 200, wherein the liquid to be pressurized is transferred from the suction compartment directly into the end compartment, the pressure acting on the low pressure seal 216B ranges from 16.272 kg/cm 2 g to 20.936 kg/cm 2 g. This pressure is significantly less than that acting on the high pressure seal of the conventional multistage pump.

TECHNICAL ADVANCES

The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a multistage pump that: - has a configuration which eliminates the usage of high pressure seals;

- has a configuration which reduces the inventory of spare components for the seals; and

- has a safe operation.

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 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.

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 a 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.

While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.