WO2023139598A1

WO2023139598A1 - A positive displacement booster pump

Info

Publication number: WO2023139598A1
Application number: PCT/IN2023/050033
Authority: WO
Inventors: Dhruv MALHOTRA; Mohammad Zakir; V Ravindra
Original assignee: Everest Blower Systems Private Limited
Priority date: 2022-01-18
Filing date: 2023-01-13
Publication date: 2023-07-27

Abstract

Disclosed herein a positive displacement booster pump (1), comprising a casing (2) provided with an inlet (3) and an outlet (4), wherein the casing (2) comprises of a rotor assembly (5) operably housed within the casing (2), and a motor (8) externally connected with the casing (2) via a portion of the rotor assembly (5), wherein said rotor assembly (5) comprises of an intermesh able self-balanced driver (5a) and driven rotor (5b), wherein each said rotor (5a and 5b) is having at least a couple of hollow lobes (9) having non-circular annulus. Disclosed herein also a self-balanced rotor assembly (5) in a positive displacement pump (1), and a rotor (5) comprising at least a couple of hollow lobes (9) having non-circular annulus, wherein said rotor (5) is provided with an internal balancing cavity (11) longitudinally designed in along and on its axis of rotation.

Description

A Positive Displacement Booster Pump

Technical Field

In general, the present invention relates to a positive displacement pump. More particularly, the present invention relates to an efficient mechanical vacuum booster pump used in various industries.

Background of the Invention

In general, positive displacement pumps or traditionally, booster pumps are known for generating vacuum in any industry where there is a requirement of high vacuum and as the name suggests, they are meant for boosting the pumping capacity to a great extent and create ultra-high vacuum as per the application. Generally, such boosters are dry pumps that work as auxiliary units to vacuum pumps. It is used in for a number of applications where a high vacuum is required, the environment is concerned, and with lower ultimate pressure.

In order to create an effective vacuum for pumping within the pump, the Dry booster pump is designed to operate at high speed, which makes it necessary for the rotors to be dynamically balanced to prevent vibration leading to premature bearing failure. A number of such rotors for booster pumps has been developed in the past to avoid the mechanical imbalance produced during the functioning of the pump. In the conventional pumps, there are hollow rotors and shafts with circular cross-section being provided through the rotor profile for smooth balancing of the rotors. The circular hollow rotors formed in the conventional pumps were either made by drilling or through mass removal during the casting stage itself, the later has been observed to face a high rejection rate due to defects in casting and also required especially skilled manpower for casting. The chances of casting defect due to extra solid mass are higher and therefore, weight optimization is also necessary to increase the efficiency of the machine.

There can be a possibility of chips or sand stuck in between holes or thin sections which come out during running conditions and damage the internals of the pump which ultimately results in lower pump life, further leading to imbalance within the pump during its operation and sand may act as an unwanted particulate responsible for intense pump vibration, scratches and internal damages of the pump on its way out through discharge, thereby, causing a major internal premature mechanical failure of the pump.

Upon contemplating the above problems in the traditional booster pumps, there is an unmet need to reconfigure the existing rotors used in the pumps for enhancing balancing of the rotors and accurately maintain size and dimensions so as to eliminate the need of material removal via drilling within the rotor leading to lower defect ratio. Also, there is a requirement to optimise the weight of rotor for minimising the power consumption. EP1043502 discloses a rotary pump has a simple construction by omitting a transmission shaft on the side of a motor and whereby makes a cost of the rotary pump as low as possible, with maintaining feature that assembling and disassembling is facilitated. The rotary pump has a main casing, a casing cover cooperated with the main casing for defining a pumping chamber therebetween, a pair of rotors received within the pumping chamber with mutually meshing pumping segments for synchronous revolution in mutually opposite directions, a space being defined in one portion of the casing cover, a cover piston being disposed within the space for movement back and forth with respect to an end surface of the rotor, and an air cylinder being mounted on the casing cover and having a piston rod, to which the cover piston is connected.

US8007264B2 discloses an improved positive displacement rotary pump apparatus and method is provided. The pump may include a front cover, a rotor body forming a chamber with the front cover, a gear case supporting a pair of hollow drive shafts, and a pair of rotors disposed in the chambers and each detachably mounted to one end of a respective hollow drive shaft via a stud that extends from the rotor through the hollow shaft to a fastener.

US1 1136970B2 discloses A rotary positive displacement pump comprising a pair of forwardly- positioned sealing arrangements and a pair of forwardly-positioned sleeves are received within a cavity providing for easy maintenance of the pump when the seals need to serviced. Each of the sealing arrangement includes a dynamic seal and a static seal. The dynamic seal abuts a corresponding sleeve and hub while a static seal is established between the corresponding sleeve and rotor.

US9017052B1 discloses an improved positive displacement pump provides improved wear characteristics. Specifically, rotor pads are provided on faces relative to an internal portion of the rotor housing as it relates to an end wall and a rear side of a cover plate. The rotor pads preferably have at least one of anti-galling and/or anti-friction or anti-wear characteristics thereby providing improvements over the prior art. A central member is preferably provided so that pad replacement may be relatively easily performed in the field in clean in place operations.

KR1020010043430 discloses the invention relates to a dry-compressing screw pump, embodied in the form of a two-shaft positive-displacement pump, having a first and a second rotor spindle disposed parallel to each other and forming a rotor spindle pair that is disposed in a closed compression chamber having an inlet and an outlet, the rotor spindles being hollow. A cooling medium is fed to a first front face of the rotor spindles and evacuated in a second front face. The cooling medium feeding and evacuation means are connected to an external cooling medium circuit. The inner surfaces of the hollow rotor spindles are embodied in such a way that the cooling medium is conveyed from the first front face to the second front face substantially under the influence of rotation of the corresponding rotor spindle.

The rotors provided in the positive displacement pumps in one or more of the above prior arts are circularly hollow and may create imbalance during the operation of the pump and defect in casting, which will not solve the above-mentioned problems in the pump. There can be a possibility of chips stuck in b/w holes or thin sections which come out during running conditions and might damage the internals of the pump, ultimately results in lower pump life.

It would be desirable, therefore, to develop an improved Booster pump, which is capable of balancing the rotor mechanically for creating an ultimate vacuum, optimising the weight of the rotor, thus, ensuring low level of vibrations and no contamination /consumption inside the body of the pump for enhancing the service life of the pump, and obviates the challenges that exist in the prior arts leading to premature failure of the pump as cited in the arts above.

Summary of the Invention

Below are various objectives and embodiments of present invention as presented herein are understood to be illustrative and not restrictive and are non-limiting with respect to the scope of the invention.

It is an objective of the present invention to provide a positive displacement booster pump capable of avoiding imbalance and intense vibration leading to premature failure of the pump.

It is an objective of the present invention to provide a positive displacement booster pump having rotors formed without involving drilling or cavity casting for mass removal on either face of rotor, therefore, eliminating the need of specially skilled manpower for casting.

It is an objective of the present invention to provide a positive displacement booster pump capable of protecting the internals of the pump from scratches and other damages on its way out through pump discharge.

It is an objective of the present invention to provide a positive displacement booster pump capable of preventing leakage from and contamination in the pump thus ensuring high volumetric efficiency for the creation of high ultimate vacuum within the pump or for another auxiliary pump unit.

It is an objective of the present invention to provide a positive displacement booster pump that consumes less power.

It is an objective of the present invention to provide a positive displacement booster pump with an extended service life. It is an objective of the present invention to provide a positive displacement booster pump which is maintenance friendly and allows convenient replacement in the pump.

It is an objective of the present invention to provide a rotor assembly having self-balanced rotors devoid of any casting defect.

In accordance with one embodiment of the present invention, there is provided a positive displacement booster pump, comprising a casing provided with an inlet and an outlet, wherein the casing comprises of a rotor assembly propelled by a plurality of gear arrangement operably housed within the casing, and a plurality of sealings provided on the ends of the rotor assembly, and a motor externally connected with the casing via a portion of the rotor assembly, wherein said rotor assembly comprises of an intermeshable self-balanced driver and driven rotor, wherein each said rotor is having at least a couple of hollow lobes (9) having non-circular annulus.

In accordance with one preferred embodiment of the present invention, there is provided a positive displacement booster pump, comprising a casing provided with an inlet and an outlet, wherein the casing comprises of a rotor assembly propelled by a plurality of gear arrangement operably housed within the casing, and a plurality of sealings provided on the ends of the rotor assembly, and a motor externally connected with the casing via a portion of the rotor assembly, wherein said rotor assembly comprises of an intermeshable self-balanced driver and driven rotor, wherein each said rotor is having at least a couple of hollow lobes having non-circular annulus, wherein each said rotor is provided with an irremovably solid rotor shaft along its axis of rotation on its two opposite ends, wherein each said rotor is provided with an internal balancing cavity longitudinally designed along and on its axis of rotation.

In accordance with one above embodiment of the present invention, wherein a bi-lobe is provided in each of the rotor, and inner longitudinal profile of one lobe is designed symmetrically on and along the axis of rotation and consistently with the non-circular annulus of the lobe so as to optimize mass distribution of the rotor assembly.

In accordance with one embodiment of the present invention, there is provided a positive displacement booster pump, comprising a casing provided with an inlet and an outlet, wherein the casing comprises of a rotor assembly propelled by a plurality of gear arrangement operably housed within the casing, and a plurality of sealings provided on the ends of the rotor assembly, and a motor externally connected with the casing via a portion of the rotor assembly, wherein said rotor assembly comprises of an intermeshable self-balanced driver and driven rotor, wherein each said rotor is having at least a couple of hollow lobes having non-circular annulus, wherein said driver rotor is operably positioned on the motor side, wherein said inlet is situated accurately on top for sucking in fluid for pumping, and said outlet is situated on the bottom for discharging the pumped fluid.

In accordance with one embodiment of the present invention, there is provided a positive displacement booster pump, comprising a casing provided with an inlet and an outlet, wherein the casing comprises of a rotor assembly propelled by a plurality of gear arrangement operably housed within the casing, and a plurality of sealings provided on the ends of the rotor assembly, and a motor externally connected with the casing via a portion of the rotor assembly, wherein said rotor assembly comprises of an intermeshable self-balanced driver and driven rotor, wherein each said rotor is having at least a couple of hollow lobes having non-circular annulus, wherein said positive displacement pump serves as an auxiliary unit for enhancing the pumping capacity of any other vacuum pump or preferably, dry screw vacuum pump, wherein the outlet of the booster pump is connected to inlet of dry screw vacuum pump.

In accordance with another embodiment of the present invention, there is provided a selfbalanced rotor assembly in a positive displacement pump, comprising a self-balanced driver rotor and a self-balanced driven rotor, wherein said rotors are configured to intermesh with each other and each is provided with at least a couple of hollow lobes having non-circular annulus and an irremovably solid rotor shaft along its axis of rotation on its two opposite ends.

In accordance with another embodiment of the present invention, there is provided a selfbalanced rotor assembly in a positive displacement pump, comprising a self-balanced driver rotor and a self-balanced driven rotor, wherein said rotors are configured to intermesh with each other and each is provided with at least a couple of hollow lobes having non-circular annulus and an irremovably solid rotor shaft along its axis of rotation on its two opposite ends, wherein each said rotor is provided with an internal balancing cavity longitudinally designed in H-shape along and on its axis of rotation, wherein a bi-lobe is provided in each of the rotor, and inner longitudinal profile of one lobe is designed symmetrically on and along the axis of rotation and consistently with the non-circular annulus of the lobe so as to optimize mass distribution of the rotor assembly.

In accordance with another embodiment of the present invention, there is provided a rotor, comprising at least a couple of hollow lobes having non-circular annulus and an irremovably solid rotor shaft along its axis of rotation on its two opposite ends, wherein said rotor is provided with an internal balancing cavity longitudinally designed along and on its axis of rotation, wherein inner longitudinal profile of lobes is designed symmetrically with respect to the other lobe on and along the axis of rotation.

In accordance with just above embodiment of the present invention, wherein said inner longitudinal profile of lobe is designed symmetrically and consistently with the non-circular annulus on and along the axis of rotation and across various cross-section of the lobes so as to optimize mass distribution of the rotor.

In accordance with any of the above embodiments of the present invention, wherein said rotor is used in a positive displacement booster pump.

Brief Description of the Drawings

Figure 1 shows the front view of the positive displacement booster pump.

Figure 2 shows the perspective view of the positive displacement booster pump illustrating internals components.

Figure 3 shows side view of the positive displacement booster pump illustrating intermeshing of the rotors inside the pump.

Figure 4a and 4b shows relative positioning of the rotors while intermeshing with each other.

Figure 5 shows a rotor to be used in a positive displacement pump.

Figure 6 shows inner cross-sectional profile of the rotor.

Detailed Description of the Invention

Referring to Figure 1 , a positive displacement booster pump (1 ), comprising a casing (2) provided with an inlet (3) and an outlet (4), wherein one end of the casing is provided with a motor externally connected with the casing (2) via an internal portion of the pump, wherein the inlet (3) is the point of entry for fluids and the outlet (4) is the point of exit for the compressed fluid, wherein the outlet is configured to be connected to another auxiliary pump for enhancing vacuum generating capacity of the another pump by transferring highly compressed pressure fluids to the inlet of the another auxiliary pump so as to create ultimate vacuum.

Referring to Figure 2, the internals of the positive displacement booster pump are illustrated, wherein a rotor assembly is housed with the casing (2) and configured to be operably driven by the gear arrangement (6) and in the return of which external motor (8) provided on the other end of the rotor assembly (5) drives rotor shaft (10) for rotating the driver rotor which in turn rotates the driven rotor. The fluids entering the inlet (3) are compressed to high pressure employing intermeshing of the driver (5a) and driven rotors (5b) in opposite directions inside the casing (2), hence trapping a fluid quantity equal to exactly one fourth the displacement of the booster. This entrapment occurs four times per revolution and the entrained air is forced around the encase (2) to the booster outlet (4), wherein the timing gears (6) accurately position the rotors (5) in relation to each other to maintain the minute clearances vital for the high volumetric efficiency of the pump. The rotor shaft (10) is also provided with a sealing (7) on both side of the rotor assembly to avoid contamination from outside to inside of the pump.

Referring to Figure 3 and 4a, illustrating intermeshing between the driver (5a) and driven rotor (5b) within the casing of the booster pump, wherein the rotor assembly having the driver (5a) and driven rotor (5b), wherein each said rotor is structurally designed to have eight shaped rotating figures having two lobes (9) with non-circular annulus at their ends, wherein the fluids entered through the inlet (3) is compressed to high pressure by being intermeshed corresponding to the rotatory intermeshing movement of the driver (5a) and driven rotor (5b), and then forced to come out of the outlet (4).

Referring to Figure 4b, illustrating intermeshing between the complete body of the driver (5a) and driven rotor (5b), wherein each rotor (5a and 5b) is provided with solid shafts (10) at their ends. Along the rotational axis of the rotors, a balancing cavity is formed in H shaped cavity in the rotor helping to maintain the centre of mass on principle axis or rotational axis for optimizing weight, ultimately making the rotors (5a and 5b) self-balanced. Further, special locking arrangement (11 a) is provided in cavity on the principal axis, helping to lock the position of the H shape cavity during the casting of the rotor, hence maintaining the uniformity of material around the axis. Also, the pump, because it is DRY type, is designed to operate at high speed, which makes it necessary for the rotors to be dynamically balanced to prevent vibration leading to premature bearing failure, therefore for the same reason, the H shape cavity is designed in such a manner that it reduces the casting defect which could occur earlier due to thick sections, extra solid mass (absence of cavity) like blow holes, and non-uniformity in thickness of the material, wherein the H shape cavity not only helps to reduce casting defects but it also optimizes the weight of rotors which make them lighter, further minimising the power consumption which ultimately results in improved pump efficiency.

Referring to Figure 5, the structural configuration or external profile of the rotor is shown, wherein said rotor (5a or 5b) comprises of a pair of self-balanced hollow lobes (9) across the non-circular and symmetrical longitudinal profile of the lobes. There are two solid shafts (10) passing through the principal axis of the rotor is provided at the two ends of the rotor.

Referring to Figure 6, inner cross-sectional profile of the rotor is illustrated, wherein there is a balancing cavity (1 1 ) provided on the principal axis of the rotor, wherein said balancing cavity latitudinally and symmetrically extends in the both the hollow lobes (9) to form depression (12) between the two opposite ends of the lobe. An inner profile of a lobe (9) is circumferentially thick at the start and end of the lobe (9) and relatively thinner and depressed in the middle portion. Along the principal axis of the rotor, the balancing cavity is formed in H shaped cavity in the rotor helping to maintain the centre of mass on principle axis or rotational axis for optimizing weight, ultimately making the rotors (5a and 5b) self-balanced. Further, a pair of special locking arrangement (11 a) is provided in cavity on the principal axis, helping to lock the position of the H shape cavity during the casting of the rotor, hence maintaining the uniformity of material around the axis.

While the invention is amenable to various modifications and alternative forms, some embodiments have been illustrated by way of example in the drawings and are described in detail above. The intention, however, is not to limit the invention by those examples and the invention is intended to cover all modifications, equivalents, and alternatives to the embodiments described in this specification.

The embodiments in the specification are described in a progressive manner and focus of description in each embodiment is the difference from other embodiments. For the same or similar parts of each embodiment, reference may be made to each other.

It will be appreciated by those skilled in the art that the above description was in respect of preferred embodiments and that various alterations and modifications are possible within the broad scope of the appended claims without departing from the spirit of the invention with the necessary modifications.

Based on the description of disclosed embodiments, persons skilled in the art can implement or apply the present disclosure. Various modifications of the embodiments are apparent to persons skilled in the art, and general principles defined in the specification can be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is not limited to the embodiments in the specification but intends to cover the most extensive scope consistent with the principle and the novel features disclosed in the specification.

Claims

We Claim:

1. A positive displacement booster pump (1 ), comprising: a casing (2) provided with an inlet (3) and an outlet (4), wherein the casing (2) comprises of: a rotor assembly (5) propelled by a plurality of gear arrangement (6) operably housed within the casing (2); and a plurality of sealings (7) provided on the ends of the rotor assembly (5); and a motor (8) externally connected with the casing (2) via a portion of the rotor assembly (5); wherein said rotor assembly (5) comprises of an intermeshable self-balanced driver (5a) and driven rotor (5b), wherein each said rotor (5a and 5b) is having at least a couple of hollow lobes (9) having non-circular annulus.

2. The positive displacement pump as claimed in claim 1 , wherein each said rotor (5a and 5b) is provided with an irremovably solid rotor shaft (10) along its axis of rotation on its two opposite ends.

3. The positive displacement pump as claimed in claim 1 , wherein each said rotor (5a and 5b) is provided with an internal balancing cavity (11 ) longitudinally designed along and on its axis of rotation.

4. The positive displacement pump as claimed in claim 1 , wherein a bi-lobe (9) is provided in each of the rotor (5a and 5b), and inner longitudinal profile of one lobe (9) is designed symmetrically on and along the axis of rotation and consistently with the non-circular annulus of the lobe (9) so as to optimize mass distribution of the rotor assembly (5).

5. The positive displacement pump as claimed in claim 1 , wherein said driver rotor (5a) is operably positioned on the motor (8) side.

6. The positive displacement pump as claimed in claim 1 , wherein said inlet (3) is situated accurately on top for sucking in fluid for pumping, and said outlet (4) is situated on the bottom for discharging the pumped fluid.

7. The positive displacement pump as claimed in claim 1 , wherein said positive displacement pump serves as an auxiliary unit for enhancing the pumping capacity of any other vacuum pump or preferably, dry screw vacuum pump, wherein the outlet of the booster pump (1 ) is connected to inlet (3) of dry screw vacuum pump.

8. A self-balanced rotor assembly (5) in a positive displacement pump (1 ) comprising: a self-balanced driver rotor (5a); and a self-balanced driven rotor (5b), wherein said rotors (5a and 5b) are configured to intermesh with each other and each is provided with at least a couple of hollow lobes (9) having non-circular annulus and an irremovably solid rotor shaft (10) along its axis of rotation on its two opposite ends.

9. The self-balanced rotor assembly as claimed in claim 8, wherein each said rotor (5a and 5b) is provided with an internal balancing cavity (11 ) longitudinally designed in H shape along and on its axis of rotation.

10. The positive displacement pump as claimed in claim 1 , wherein a bi-lobe (9) is provided in each of the rotor (5a and 5b), and inner longitudinal profile of one lobe (5a and 5b) is designed symmetrically on and along the axis of rotation and consistently with the non-circular annulus of the lobe so as to optimize mass distribution of the rotor assembly (5).

11 . A rotor (5), comprising at least a couple of hollow lobes (9) having non-circular annulus and an irremovably solid rotor shaft (10) along its axis of rotation on its two opposite ends, wherein said rotor (5) is provided with an internal balancing cavity (11 ) longitudinally designed in H Shape along and on its axis of rotation, wherein inner longitudinal profile of lobes (9) is designed symmetrically with respect to the other lobe on and along the axis of rotation.

12. The rotor (5) as claimed in claim 11 , wherein inner longitudinal profile of lobe (9) is designed symmetrically consistently with the non-circular annulus on and along the axis of rotation and across various cross-section of the lobes (9) so as to optimize mass distribution of the rotor (5).

13. The rotor as claimed in claim 11 , wherein said rotor (5) is used in a positive displacement booster pump.