WO2017154023A1

WO2017154023A1 - Motor with positive displacement helical pump inside motor shaft

Info

Publication number: WO2017154023A1
Application number: PCT/IN2017/050083
Authority: WO
Inventors: Ankur Natwarlal PATEL
Original assignee: Sona Pumps
Priority date: 2016-03-07
Filing date: 2017-03-06
Publication date: 2017-09-14

Abstract

The present invention relates to motor with positive displacement helical pump inside motor shaft comprises a stator body (5) within which the rotor (14) is rotatably mounted, helical rotating shaft (15) rotatably positioned inside the rotor (14) and having helical inner surface and helical stationary shaft (16) having number of lobes (16a) on outer surface thereof. The helical stationary shaft (16) is fixedly coupled in non‐rotatable position at its both ends with the fluid inlet means through which fluid enter and the fluid outlet means through which fluid exit the pump. Here, the helical rotating shaft (15) is rotated with respect to helical stationary shaft (16) along with the rotation of rotor (14) through which the fluid is pumped from inlet means to outlet means through cavities (17) formed between the lobes (16a) and helical inner surface (15d). Thus pumping and motoring functions are performed within motor section (2).

Description

MOTOR WITH POSITIVE DISPLACEMENT HELICAL PUMP INSIDE MOTOR SHAFT

Field of Invention

The present invention relates to a motor having motor shaft carrying positive displacement helical pump inside thereof for pumping the fluid and more particularly, it relates to a motor having motor shaft carrying positive displacement helical pump inside thereof that eliminates various stages of pumping portion.

Background of the Invention

Motor driven pumps are widely used for transferring liquids from sumps and wells, lifting water from sump and other water reservoirs like bore well, open well, for dewatering purpose and also in line boosting application by enclosing the body of the pump in outer shell.

The centrifugal pumps are most commonly used for this purpose. These pumps include motor and different types of impellers and diffusers for pumping the liquid and a seal section that prevents the ingress of the pumped fluid along the motor shaft. In addition, today the water levels are going deep and hence requirement to get the water has crossed 1000 feet and more. The reliability of such conventional pump depends on its Length/Diameter ratio and hence in order to elevate the liquid from below level from the earth surface, the dimension and power requirement for operating the pump is also increased. Because power uptake typically increases with increasing flow, the motor must be large enough to handle the maximum anticipated additional load. Further, due to number of components, the structure of pump becomes intricate and the problem of wearing of components occurs. Further, in this conventional technology, the heat generated during working of motor should be dissipated. Hence, ample amount of water is required as a coolant to take away the heat from motor. Further, centrifugal pump reacts with changes in pressure. As the pressure increase, the flow rate of effluent is decreased. Hence, the centrifugal pumps are not suitable for pumping of viscous liquid.

In order to solve above problems, the progressive cavity pump came into existence. Unlike, centrifugal pump, the progressive cavity pump maintain the flow regardless of pressure. According to one typical configuration of progressive cavity pump, it comprises a helical metal rotor mounted to turn inside a compressible stator that is made of elastomer and whose inside shape is helical. The driveshaft is coupled to the rotor and supported by the bearing assembly. Said rotor rotates relative to the stator in response to the rotation of the driveshaft and thus fluid is pumped through the cavities. However, several deficiencies have become apparent in the currently known progressive displacement pumps. One of them is arrangement of coupling rotor to the rotary drive shaft needs long length coupling mechanism which greatly adds to overall size of the device. Particularly, the connecting rods associated with universal joints can substantially increase the overall length of the pump. Additionally, the large number of moving parts experience wear and eventually fail, resulting in mechanical problems which increase with the complexity and number of parts in the drive arrangement. Contaminants present in the fluids transported by progressing cavity pumps tend to work into and joints of the pump drive systems, further accelerating wear and failure of parts.

Hence, it is desperately needed to invent a positive displacement helical pump that is a simple and compact in construction, relatively low cost and having open loop cooling system for an electric motor powered pump.

Object of the Invention

The main object of present invention is to provide a motor with positive displacement helical pump inside motor shaft that overcomes the above mentioned drawbacks of the prior art.

Another object of present invention is to provide a motor with positive displacement helical pump inside motor shaft which is simple and compact in construction. This invention reduces the size of the machine, maintenance due to wear and tear of components and eliminates the need for an external drive system. Yet another object of present invention is to provide a motor with positive displacement helical pump inside motor shaft that is economical and configured for easy assembling and disassembling whereby the pump components are easily re-used and replace for service, repair or analysis purposes.

Further object of present invention is to provide a motor with positive displacement helical pump inside the motor shaft wherein drive means for pumping the fluid are included along the length of the rotor so that mechanism of universal joints is eliminated.

One more object of present invention is to provide a motor with positive displacement helical pump inside the motor shaft that avoids the various stages of pump portion by eliminating external drive arrangement for driving the rotor.

Summary of the Invention

The present invention relates to a positive displacement helical pump that avoids extended pump portion by including the motor inside the motor shaft. Said pump comprises a stator body within which the rotor is rotatably mounted, a rotating helical shaft rotatably positioned inside the rotor and having helical inner surface and a helical stationary shaft having a number of lobes on outer surface thereof. The helical stationary shaft is fixedly coupled in non-rotatable position at its both ends with the fluid inlet means through which fluid enter and the fluid outlet means through which the fluid exit the pump. Here, the helical rotating shaft is rotated with respect to the helical stationary shaft along with the rotation of rotor through which the fluid is pumped from inlet means to outlet means through the cavities formed between the lobes of the helical stationary shaft and helical inner surface of the rotating helical shaft. Said configuration of pump according to present invention eliminates the requirement of the external drive system for rotating the rotor and leads to the compact size of the pump.

Brief Description of the Drawing

Objects and advantages of the invention will be apparent from the following detailed description taken in conjunction with the accompanying figures of the drawing wherein: Fig. 1 illustrates a perspective, partial cut-away view of a motor with positive displacement helical pump inside motor shaft according to present invention.

Fig. 2 illustrates an exploded view of a motor with positive displacement helical pump inside motor shaft according to present invention. Detailed Description of the Invention

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of the construction and arrangement of parts illustrated in the accompany drawings. The invention is capable of other embodiments, as depicted in different figures as described above and of being practiced or carried out in a variety of ways. It is to be understood that the phraseology and terminology employed herein is for the purpose of description and not of limitation.

From cut-away perspective view of a motor with positive displacement helical pump (1) according to present invention as shown Fig. 1, said pump (1) mainly comprises a motor section (2), a fluid inlet means here as a suction chamber (3) and fluid outlet means here as a discharge housing (4). Said positive displacement helical pump (1) provides an inline configuration for pumping the fluid from the suction chamber (3) to discharge housing (4) flow through the motor section (2) as described below.

Before explaining the present invention, it is to be noted that the term "fluid" includes, but not limited to, water, oil, paint or other gaseous and liquid multistage fluid. Further, it is to be also noted that the term "motor shaft" is referred herein as a "helical rotating shaft". Now according to exploded perspective view of the pump (1) shown in Fig. 2, the aforesaid components are shown co-axially aligned with respect to an axis (A). According to present invention, said motor section (2) comprises a cylindrical stator body (5) having a first and second opposite circular ends (5a) and (5b) and a substantially cylindrical inner surface. The outer surface of said stator body (5) is configured with laterally extended ports (6) at the ends (5a) and (5b). A stator stack lamination (7) is coaxially disposed within the stator body (5). This stator stack (7) having an outer cylindrical surface that engages with the inner surface of the stator body (5). Said stator stack (7) comprises stator windings (8) in its inner surface which are watertight plastic coated or made enamelled watertight winding filled with resin or oil and that is energized by a supply of electrical current to create an alternating electromagnetic field. Further, said suction chamber (3) includes a circular flange portion (9) having an axially extended inlet port (10) through which the fluid to be pumped is moved into the motor section (2). Said discharge housing (4) is cylindrical and includes a flange portion (11) having an axially extending discharge port (12) which allows the pumped fluid to exit from the pump. Said discharge port (12) is adapted to allow connection to pipes, hoses, or other fluid source for supplying the fluid to be pumped at desired location. Said flange portion (9) of the suction chamber (3) is removably and closely anchored at the one end (5a) of the stator body (5) and the flange portion (11) of the discharge housing (4) is removably and closely anchored at another end (5b) of the stator body (5) through a laterally extending fastener (13) that passes through the laterally extended ports (6). Said arrangement provides an inline configuration wherein the fluid to be pumped is entered through the inlet port (10) and discharged through the discharge port (12).

Now as shown in Fig. 1 and 2, said motor section (2) comprises a rotor (14) being coaxially and rotatably disposed within the stator stack laminations (7). Said rotor (14) having an annular internal diameter (14a) within which a helical rotating shaft (15) is adjustably mounted such that inner surface (14a) of the rotor (14) is confirmed by a projected portion (15a) of an outer surface of the helical rotating shaft (15) wherefrom the portion (15b) and (15c) are extended equidistantly and longitudinally with respect to axis-A. Said projected portion (15a) is formed along and middle of the length of the helical rotating shaft (15). The inner surface of the helical rotating shaft (15) is configured with at least two internal helical grooves (15d) which define an internal bore extending axially therethrough in its inner surface. A helical stationary shaft (16) having at least one lobe (16a) is concentrically disposed within the internal bore so that the external helical lobe (16a) of the helical stationary shaft (16) and the internal helical grooves (15d) of the helical rotating shaft (15) define a plurality of cavities (17) (shown in Fig. 1) there between. The helical rotating shaft (15) is typically formed from a resilient and flexible elastomeric material and the rotor (14) and the helical stationary shaft is typically manufactured from a metallic material; however, it is within the scope of the invention to form the rotor and stationary shaft from a resilient material and to form the rotating shaft from rigid metallic material.

Said stator windings (8) are connected via a waterproof cable (not shown) with a waterproof commutated electronic circuitry (not shown) which is generally adapted in a winding protection cap (not shown) mounted within said stator body (5) for rendering the power supply to the stator windings (8) whereby said stator winding (8) generates a magnetic field so that interaction of the rotor magnetic field and the stator windings magnetic field causes the rotor (14) to rotate.

Referring continues with Fig. 2, said helical stationary shaft (16) is firmly held between the flange portion (9) and the flange portion (11) by axially anchoring the respective ends of the said helical stationary shaft (16) with the flange portion (9) and (11) through a locking arrangement (18). Thus, the helical stationary shaft (16) is remained stationary during the operation of the pump (1) according to present invention. Hence, unlike conventional PDP (positive displacement pump), the cavities are defined by the rotation of the helical rotating shaft (15) rather than the rotation of the helical stationary shaft (16) in present invention.

Means for reducing friction, preferably in the form of plurality of radial or thrust bearings (19, 20), are disposed at selected locations over a length of the helical rotating shaft (15). Said Bearings (19, 20) reduce frictional rotation of the helical rotating shaft (15) and also concentrically align the helical rotating shaft (15) about the axis (A) within the rotor (14). Further, the flange portion (9) is provided with a fluid-tight seal (mechanical seal) (21) for preventing the pumped fluid to leak inside the stator windings (8).

During operation of the positive displacement helical pump (1) according to present invention, the fluid to be pumped is entered within the cavities (17) through the inlet port (10) of suction chamber (3) where it fills the first set of the cavities (17). When said stator windings (8) are energized through the power supply rendered from commutated electronic circuitry, said rotor (14) is magnetized and rotates in conventional manner. As the rotor (14) adjacent with the outer surface of the helical rotating shaft (15), said helical rotating shaft (15) is also rotated along with the rotation of the rotor (14). As the helical rotating shaft (15) turns, the cavities (17) are formed in reverse direction of rotation of the helical rotating shaft (15) between the lobes (16a) of the helical stationary shaft (16) and the internal helical grooves (15b) of the helical rotating shaft (15) and progress from fluid inlet section to fluid outlet section. During a single 360 degree revolution of the helical rotating shaft (15), one set of cavities (17) is opened or created at the fluid inlet means at exactly the same rate that a second set of cavities (17) is closing or terminating at the fluid outlet means which results in a predictable, pulsationless flow of pumped fluid. Hence, no any external drive means are required for creating cavities and for pumping the fluid. Thus, rotation of the helical rotation shaft (15) inside the rotor (14) pumps the fluid from the inlet to the outlet. Here, the cavities move when the helical rotating shaft (15) is rotated but their shape or volume does not change.

From aforesaid explanation, it is seen that the drive means for rotation of the helical rotating shaft (15) are included along the entire length of the rotor (14) and no any universal joint and external drive system is required to rotate the helical rotating shaft and to pump the fluid. Moreover, the pumping functions through the positive displacement of cavities are performed inside the motor shaft (rotating helical shaft) (15). Hence, the function of typical motor and progressive cavity pump is performed and integrated within the motor (motor section (2)) of present invention. Further, in the pump (1) according to present invention, the water transferred through the cavity (17) cool the motor section (2) that avoids necessity of external coolant for dissipating the heat produced during the rotation of the rotor (14) and the helical rotating shaft (15). Thus, extended pump portion and driving system is eliminated in the pump according to present invention. Further, the bearings (19, 20) are lubricated and cooled by the pumped water. However, in case of other liquids, said bearings (19, 20) are properly sealed. The invention has been explained in relation to specific embodiment. It is inferred that the foregoing description is only illustrative of the present invention and it is not intended that the invention be limited or restrictive thereto. Many other specific embodiments of the present invention will be apparent to one skilled in the art from the foregoing disclosure. All substitution, alterations and modification of the present invention which come within the scope of the following claims are to which the present invention is readily susceptible without departing from the spirit of the invention. The scope of the invention should therefore be determined not with reference to the above description but should be determined with reference to appended claims along with full scope of equivalents to which such claims are entitled.

Claims

We Claim,

1. A motor with positive displacement helical pump inside motor shaft comprises: a cylindrical stator body (5) having a circular inner surface with a first end (5a) and a second end (5b); a stator lamination stack (7) mounted within the stator body (5) and having a stator winding (8) formed therein; a rotor (14) concentrically mounted inside said stator stack (7) and rotated in response to the electromagnetic field generated through the stator winding (8); a helical rotating shaft (15) having a inner longitudinal bore and at least two internal helical groove and being rotatably positioned within the rotor (14) and rotated along with the rotation of the rotor (14) which in turn causes the fluid to pump therethrough; a helical stationary shaft (16) having at least one helical lobes (16a) and longitudinally disposed within the internal bore of the helical rotating shaft

(15); a fluid inlet means for allowing fluid to enter in the pump, said fluid inlet means positioned adjacent to said first end (5a) of the stator body (5); a fluid outlet means for allowing fluid to discharge from the pump, said fluid outlet means positioned adjacent to said second end (5b) of said stator body (5); wherein each respective end of said helical stationary shaft (16) is fixedly coupled to the fluid inlet means and the fluid outlet means through a locking arrangement (18) in non-rotatable position; wherein said helical rotating shaft (15) rotates with respect to helical stationary shaft (16) to form a cavities (17) therebetween through which fluid to be pumped progress from the fluid inlet means to fluid outlet means.