Description:TITLE OF THE INVENTION:
Centrifugal self-priming pump with inbuilt reservoir

FIELD OF THE INVENTION:
The present invention relates to the field of pumps and provides a centrifugal self-priming pump which has an inbuilt reservoir to retain a sufficient amount of liquid, to initiate the pumping process.

BACKGROUND OF THE INVENTION:
A pump is a mechanical device that moves fluids, gases or slurries from one place to another. Pumps have both, domestic and industrial use like pumping water from wells, aquarium filtering, pond filtering and aeration, in the car industry for water-cooling and fuel injection, in the energy industry for pumping oil and natural gas or for operating cooling towers and other components of heating, ventilation and air conditioning systems, etc. They work by converting mechanical energy into hydraulic or pneumatic energy. There are three basic types of pumps: positive-displacement, centrifugal and axial-flow pumps.
Positive-displacement pumps: A positive-displacement pump makes a fluid move by trapping a fixed amount of fluid and forcing that trapped volume into the discharge pipe. Some positive-displacement pumps use an expanding cavity on the suction side and a decreasing cavity on the discharge side. Liquid flows into the pump as the cavity on the suction side expands and the liquid flows out of the discharge, as the cavity collapses. The volume is constant through each cycle of operation.
Centrifugal pumps: Centrifugal pumps are used to transport fluids by the conversion of rotational kinetic energy to the hydrodynamic energy of the fluid flow. The rotational energy typically comes from an engine or electric motor. The fluid enters the pump impeller along or near to the rotating axis and is accelerated by the impeller, flowing radially outward into a diffuser or volute chamber (casing), from which it exits.
Axial-flow pumps: An axial-flow pump is a common type of pump that essentially consists of a propeller in a pipe. The propeller can be driven directly by a sealed motor in the pipe or by electric motor or petrol/diesel engines mounted to the pipe from the outside or by a right-angle drive shaft that pierces the pipe. Fluid particles, in course of their flow through the pump, do not change their radial locations since the change in radius at the entry (called 'suction') and the exit (called 'discharge') of the pump is very small.
Centrifugal pumps have many advantages over other types of pumps including energy efficiency, simplicity, durability, low maintenance, space efficiency etc.
A centrifugal self-priming pump is a type of pump that can automatically remove air from the pump's suction line and casing, allowing it to start pumping without manual priming. A self-priming centrifugal pump has two phases of operation: priming mode and pumping mode. In its priming mode, the pump essentially acts as a liquid-ring pump. The rotating impeller generates a vacuum at the impeller’s ‘eye’ which draws air into the pump from the suction line. At the same time, it also creates a cylindrical ring of liquid on the inside of the pump casing. This effectively forms a gas-tight seal, stopping air returning from the discharge line to the suction line. Air bubbles are trapped in the liquid within the impeller’s vanes and transported to the discharge port. There, the air is expelled and the liquid returns under gravity to the reservoir in the pump housing. Gradually, liquid rises up the suction line as it is evacuated. This process continues until liquid replaces all the air in the suction piping and the pump. At this stage, the normal pumping mode commences, and liquid is discharged.
When the pump is shut off, the design of the inbuilt priming reservoir ensures that enough liquid is retained so that the pump can self-prime on the next occasion when it will be used. If a pump has not been used for a while, it is important to check for losses from the casing due to leaks or evaporation before starting it.
A number of self-priming centrifugal pumps are available in the prior art.
US11905976 discloses a quick no-water startup apparatus for a centrifugal pump which includes, from top to bottom in sequence, one-way passages (1), a self-priming chamber housing (41), sliding devices (5), a self-priming chamber (4), chamber partition plates (2) a concave-convex impeller (3), inlet channels (6) connected on two sides of the self-priming chamber (4), a spring device (7) of an upper-side x-shaped gas-liquid separation device, the upper-side x-shaped gas-liquid separation device (8), upper and middle-side gas-liquid separation device connecting shafts (9), a middle-side gas-liquid separation device (10), lower-side backflow-type gas-liquid separation devices (11), v-shaped backflow channels (122), an inverted v-shaped inlet channel (121), and an inlet. The quick no-water startup apparatus of the present invention enables the centrifugal pump to directly enter a normal operating condition after no-water startup, and 36 times of air exhaust can be completed while the concave-convex impeller (3) in the self-priming chamber (4) rotates by a circle in the early stage. Besides, the apparatus is provided with the upper, middle, and lower gas-liquid separation devices to fully realize separation of gas and liquid, so that gas can be exhausted more quickly and the chamber is filled with water. Therefore, the working efficiency is significantly improved and the operation process is greatly simplified.
US2023391101 discusses a fluid reservoir for a fluid ejection head structure and a method for priming a fluid ejection head for a fluid dispensing device. The fluid reservoir includes an enclosed fluid cavity therein configured for containing fluid, a fluid outlet in fluid flow communication with the enclosed fluid cavity, and a flow inducing pump attached to the fluid reservoir opposite the fluid outlet.
WO 2022128545 This patent application describes a self-priming pump comprising a pump impeller (5) which is configured so that, during operation, the axis of the pump impeller (5) is vertical with an impeller inlet (10) disposed above an impeller outlet (11), the pump comprising a toroidal liquid reservoir (1) around the pump impeller (5) and a connection means (8) for connecting the liquid reservoir (1) to the pump impeller (5), at a connection point (9). The connection point (9) is positioned below the impeller inlet (10) so as to form a siphon, and the fluid passage cross-section (15) in the connection means (8) increases in the direction of circulation of the liquid in the pump. The invention also relates to a turbogenerator and a closed circuit comprising such a pump, as well as to the use of the closed circuit in a vehicle.
WO 2023279769 gives a self-priming centrifugal pump, comprising a pump body (1), a water inlet (11), a water outlet (12), an impeller (13), a water intake channel (2), an inlet support assembly (3), a flow guide assembly (4), and a pressure compensation assembly (5), wherein the water intake channel (2) is provided in the pump body (1), one end of the water intake channel (2) being in communication with the outside by means of the horizontally arranged water inlet (11), and the other end thereof being in communication with the outside by means of the vertically arranged water outlet (12). The water level of the water inlet of the centrifugal pump is raised by means of the inlet support assembly (3), which avoids the circumstance where injected water for start-up flows from the water outlet (12) and affects the start-up of the centrifugal pump, and ensures that the interior of the pump body (1) is fully and smoothly filled with the water for start-up. The impeller (13) stops rotating, and under the action of a water baffle plate (33), the remaining water inside the pump body (1) is blocked by the water baffle plate (33) and cannot flow out from the water inlet (11), and is thus stored inside the pump body (1) to serve as water for start-up during the next start-up of the centrifugal pump, thereby reducing preparatory work for the next start-up of the centrifugal pump, and making the start-up of the centrifugal pump smoother.
GB691362 relates to a self-priming centrifugal pump, wherein the pump housing includes a reservoir through which the pump discharge passes on its way to the discharge outlet, and the diffuser. which is intermediate the impeller and the reservoir, contains a series of continuous repetitive groups of flow passages of unequal size. To facilitate priming, the disturbing effect of counterflow from the diffuser passages 20 towards the impeller 11 is increased by making every alternate passage 20 about twice the width of the other passages 20, and providing alternate diffuser vanes 24 with a larger clearance from the impeller periphery than the remaining vanes 24: At least one priming hole 201 communicating with a liquid reservoir 10 is provided in each larger diffuser passage and, it may be, in each smaller diffuser passage also. Check valves 16 and 22 are provided in the suction and discharge respectively. The diffuser passages may be arranged in repetitive groups of three or more passages instead of groups of two as shown. There may be a float-operated ventilating air separator in series with the pump. The Specification as open to inspection under Sect. 91, comprises also the statement that the liquid reservoir may be separate from the pump housing.

JP 2018-204566 provides a self - priming centrifugal pump which comprises an impeller, and a pump casing storing the impeller. In the pump casing, provided is a gas-liquid separation chamber configured to separate fluid discharged from the impeller during self - priming operation into liquid and gas. The pump casing has a guide part arranged between the gas-liquid separation chamber and the impeller so as to guide fluid. The part guide comprises a flow passage having an inlet opened to the inside of the gas-liquid separation chamber so as to receive part of swirl flow of the liquid in the gas-liquid separation chamber, and outlet opened toward an outer peripheral part of the impeller, where the inlet is arranged on an upstream side of the swirl flow with respect to the outlet.
KR 101399547 relates to a self-priming water pump with a large suction capacity to be directly coupled to an engine according to the present invention relates to a direct-coupled structure of a pump and a movable plate of an engine to be installed on a road of a river, a stream, and a reservoir to function as a pumping facility. The self-priming water pump with a large suction capacity to be directly coupled to an engine comprises a power transmission shaft directly coupled to the engine; an impeller which is joined to the power transmission shaft, which is installed inside a pump housing, and which has an inlet and an outlet; and an inlet pipe and an outlet pipe on one side and the other side of the pump housing. Therefore, the self-priming water pump is suitable for supplying water to a place at a long distance or through a long intake pipe as high capacity suction lift per hour and stable and smooth large capacity pumping operation are available; and enables economically efficient pumping of water using a minimum workforce as the self-priming water pump is installed in a place to which no electricity is supplied.
AU 2019101710 provides an air-liquid mixed type self-priming centrifugal pump adopts a liquid axial return pump body. In use, after the pump is started, an impeller rotates and both liquid stored in a suction chamber and air in a suction pipeline are introduced into and mixed completely in the impeller. Under the action of a centrifugal force, a pressure is reduced at a front end, a flap valve is opened under an impact force of water, and the liquid enters the pump. Meanwhile, the liquid mixed with the air in the impeller flows towards an outer edge of a volute chamber and forms a white foam band with a certain thickness and an adjustment rotation liquid ring at an outer edge of the impeller. The air-liquid mixture enters an air liquid separation chamber through the pump body, and at this point, since the speed of the liquid is reduced suddenly, the lighter air is separated from the mixture and discharged upwards continuously via a discharge opening of the pump body. The deaerated liquid returns to a liquid reservoir, and enters the impeller via a liquid return hole again. The liquid in the impeller is mixed with the air sucked from the suction pipeline again, and flows towards the outer edge of the impeller again under the action of the impeller rotating at a high speed. The process is repeated until no air is present in the suction pipeline, and the self-priming process is then completed.
ES 220840 gives a self-priming fluid pump, which has in combination: a pump box that includes a reservoir for a fluid reservoir, a suction inlet and a discharge outlet in the pump housing, a centrifugal rotor arranged for axial rotation inside the box for exerting driving forces for the liquid advancing from the suction inlet through the reservoir to the discharge outlet, said rotor having its center of rotation in communication with said suction inlet, and a diffuser fixed between the periphery of the rotor and reservoir of the reserve fluid and containing a series of radiant flow passages extending in the same direction separated from each other by the use of curved blades, the alternate blades being equally spaced from the periphery of the rotor but being consecutive blades unequally spaced from the periphery of the rotor, and the alternating passages with ports being provided for direct communication d from the impulse reservoir of the pump.
CN 208416964 provides an energy -efficient self priming centrifugal pump, including inlet tube, reservoir chamber and impeller, be equipped with suction chamber in the reservoir chamber, suction chamber encloses by upper plate, lower plate and with the two mutually perpendicular's curb plate, the hole h of upper plate upwards extends along the pore wall and forms the outlet pipe, and the outlet pipe is connected with impeller inlet, and formation is connected by curve a, helix b, curve c and line d in proper order to the edge line of curb plate cross section, smooth transition between line an and line c and the line b, curb plate division porose k that line d belonged to, hole k and advance water piping connection, line b and line an and line c's nodical m and n, m, n and hole h's centre of a circle o is located same straight line to point on the helix b and the line segment length between the o are R, and the contained angle that uses point and line segment between the o and the line segment between m and the o on the helix b is theta, R=D0 (A+B theta C). The utility model discloses self priming centrifugal pump compromises efficiency, inhales performance, hydraulic performance and operational reliability performance certainly, can be used widely.
IN202141032705 discloses a regenerative self-priming pump with a novel design comprising of an impeller [1], with multiple blades [2] extending from the stem [3] which separates the two sides of the impeller and provides structural support to the blades, a casing [4] component which is designed to have the inlet [5] and exit [6] ports for fluid being pumped and a bracket [7] to enclose the fluid channel region around the impeller which is attached to the motor rotor shaft [8] by thread and locked to its position by a lock nut [9] as shown in Figure 1. The pump uses a mechanical seal [10] for sealing the motor from the fluid. The specially designed chambers in the casing [4] helps in fast self-priming of the pump.
Although a number of centrifugal self-priming pumps are available in the prior art, in most centrifugal pumps, the pump casing and impeller must be filled with liquid, before starting the pumping. To remove a large amount of trapped air, particularly in long suction lines, a self-priming pump may take longer to clear the air from the system. Moreover, in dairy industries, non-return valves are installed near the pump’s discharge side. So when a CLASP pump removes air from the suction side to the discharge side, air gets trapped between the pump casing and the non-return valve, which cannot lift the non-return valve’s disc, causing airlock. Hence a self-priming centrifugal pump, which facilitates rapid air removal and allows the liquid to reach the pump impeller more quickly, is the need of the day.

OBJECT OF THE INVENTION:
The main object of the invention is to provide a centrifugal self-priming pump with inbuilt reservoir which facilitates rapid air removal, allowing the liquid to reach the pump impeller quickly.
Another object of the invention is to provide a centrifugal self-priming pump with inbuilt reservoir which removes large volumes of air, reducing the pumps workload and improving performance.
Still another object of the invention is to provide a centrifugal self-priming pump with inbuilt reservoir which has an inbuilt priming reservoir to retain enough liquid for self-priming the pump on the next occasion of its use.
Yet another object of the invention is to provide a centrifugal self-priming pump with inbuilt reservoir which is economical.

SUMMARY OF THE INVENTION:
The present invention relates to a centrifugal self-priming pump with inbuilt reservoir which reservoir holds a fixed amount of liquid for initial priming of the pump. During priming, the rotating impeller generates a ring of liquid and churns the air within the casing chamber. Due to the density difference, the air escapes through the discharge side, creating a vacuum at the center of the impeller or suction side, causing rapid suction of the liquid in the pump. An inbuilt air-vent valve on the suction side of the pump facilitates rapid air removal from the idle pump, due to which the liquid reaches the pump impeller more quickly. A casing bridge hole is provided which opens in the reservoir and transfers the unused volume of the liquid to the reservoir for self-priming during future use. This centrifugal self-priming pump assists in rapid priming of the pump including those with long pipelines.

BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 gives the drawing of the centrifugal self-priming pump with inbuilt reservoir along with the motor.
Fig. 2(A) gives the specific drawing of the centrifugal self-priming pump with inbuilt reservoir.
Fig. 2(B) gives the detail view of the casing bridge hole.
Fig. 3(A) gives the front view of the inbuilt reservoir.
Fig. 3(B) gives the cross-section view of the inbuilt reservoir.
Fig. 4(A) gives the front view drawing of the full volume of centrifugal pump cavity.
Fig. 4(B) gives the back view drawing of the full volume of centrifugal pump cavity.
Fig. 4(C) gives the drawing displaying the centrifugal pump impeller in the cavity.
Fig. 5(A) gives the front view of the section of chamber (inbuilt reservoir) displaying the volume of the fluid when the pump is in OFF condition.
Fig. 5(B) gives the side view of the section of chamber (inbuilt reservoir) displaying the volume of the fluid when the pump is in OFF condition.
Fig. 6(A) gives the front view of the section of chamber (inbuilt reservoir) displaying its volume after the pump has started functioning.
Fig. 6(B) gives the side view of the section of chamber (inbuilt reservoir) displaying its volume after the pump has started functioning.

DETAILED DESCRIPTION:
The nature of the invention and the manner in which it is performed is clearly described in the complete specification. The invention has various components and they are clearly described in the detailed description.
Priming a pump, before starting its functioning, is the process of filling the pump with the liquid it has to pump, removing the air within and creating a seal between the casing and impeller. It is necessary because when the impeller is full of air, airlock occurs, which prevents the pump from creating suction to bring in the liquid. For priming, the pump casing is filled with liquid to be pumped. The impeller creates a vacuum that pulls air into the pump from the suction line. A cylindrical ring of liquid forms inside the pump casing, creating a gas-tight seal. Due to centrifugal force, air bubbles are trapped in the liquid and transported to the discharge port from where they are expelled out. The liquid rises up the suction line, replacing the air, following which the pump is normally used for pumping the liquid. However priming pumps attached to longer suction lines becomes difficult, as larger quantity of air needs to be removed from the pipelines to pump the liquid.
The present invention provides a centrifugal self-priming pump with inbuilt reservoir which has the capacity to retain enough amount of liquid such that the pump can self-prime on the next occasion of use. It has an inbuilt air-vent valve which facilitates rapid air removal from the long suction lines such that the liquid quickly reaches the impeller and pumping can be started. Moreover a hole has been provided to let in the remaining liquid or total liquid contained in the reservoir, for the next priming cycle.
Fig. 1 gives the drawing of the centrifugal self-priming pump with inbuilt reservoir along with the motor. The various parts of the centrifugal self-priming pump are:
1 – prime mover / motor
2 – foot
3 – shaft
4 – lantern
5 – casing chamber
6 – spool
7 – centrifugal pump impeller
8 – discharge port
9 – inbuilt reservoir
10 – air-vent valve
11 – suction port
12 – casing bridge hole
13 – liquid
The prime mover / electric motor (1) gives power to the pump for pumping the liquid (13). Any motor can be selected depending upon the design and head and flow requirement of the liquid. The motor is assembled with a foot (2) for pump support and height adjustment. The motor is connected to the shaft (3) which transmits power and torque to the impeller. The shaft used in the present invention is with key less coupling because a keyless connection transmits more torque than a keyed connection and provides a more secure connection, as the shaft surface contact area is increased. Moreover, the self-centered design increases the life of the mechanical seal. The lantern (4) acts as a bridge between the motor and pump cover. The pump casing (5) includes an inbuilt reservoir which holds a calculated amount of the liquid (13) for initial priming of the pump.
When the motor (1) is switched ON, the centrifugal pump impeller (7) in the casing chamber (5) rotates, creating a ring of liquid which churns the air within with the help of centrifugal force. Due to the density difference, air escapes through the discharge port (8), creating a vacuum at the center of the impeller (‘eye’ of the impeller) or the suction area such that the liquid (13) rises in the suction line and is sucked inside, and sent through the discharge port (8) commencing the normal pumping mode to pump the liquid.
A bridge hole (12) provided in the casing helps utilize the unused liquid (13) volume in the reservoir, for self-priming of the pump. On the spool (6) near the suction port (11), an air vent valve (10) is provided, which removes a large volume of trapped air present in the pump suction line when it is inactive, thereby reducing the pump’s workload and improving its performance. A centrifugal pump impeller (7) is present in the casing chamber, which transfers energy from the motor to the liquid being pumped. The impeller’s rotation creates a centrifugal force which moves the liquid away from the pump’s center with high velocity and pressure, towards the discharge port (8) . The centrifugal pump impeller (7) in the casing chamber, consumes lesser power as compared to a liquid ring self-priming pump impeller, due to its design.
Fig. 2(A) gives the specific drawing of the centrifugal self-priming pump with inbuilt reservoir which clearly displays the centrifugal pump impeller (7) in the casing chamber (5), with the inbuilt reservoir (9) containing the liquid (13). The inset image displays the casing bridge hole (12) present between the casing chamber (5) and the inbuilt reservoir (9).
Fig. 2(B) gives the detail view of the casing bridge hole (12) which is present on the inbuilt reservoir (9) and helps in utilizing the unused liquid present in the reservoir, for self-priming of the pump, by allowing it to flow out from the reservoir to the impeller and generate a ring of liquid which enables the churning air to escape through the discharge port, thereby creating a vacuum near the suction port (11) which enables the flow of the liquid into the pump, which is then pumped out with pressure and velocity.
Fig. 3(A) gives the front view of the inbuilt reservoir and Fig. 3(B) gives the sectional side view of the inbuilt reservoir. As shown in the figure, the casing bridge hole (12) is present on the top of the inbuilt reservoir.
Fig. 4(A) gives the drawing of the full chamber for volume calculation, Fig. 4(B) gives the drawing displaying the cavity area for volume calculation and Fig. 4(C) gives the drawing displaying the impeller whose volume is to be subtracted for volume calculation. Suppose the volume of the full chamber is X1 liters. The volume of the inside cavity of the reservoir will be:
Inside cavity volume = Cavity volume – Impeller volume
= X2 – X3 = X liters.
Thus, the actual volume of liquid required for priming the pump will be X liters.
Fig. 5(A) gives the front view of the section of chamber displaying its volume before the pump has started functioning and Fig. 5(B) gives the side view of the section of chamber displaying its volume before the pump has started functioning.
Fig. 6(A) gives the front view of the section of chamber displaying its volume after the pump has started functioning and Fig. 6(B) gives the side view of the section of chamber displaying its volume after the pump has started functioning.
Suppose the chamber volume level when the pump is not functioning is Y1 liters. The volume of the inside cavity when the pump is not functioning will be:
Inside cavity volume when pump is not functioning = Cavity volume – Impeller volume
= Y2 – Y3 = Y liters
Thus the actual volume of the liquid in the cavity when the pump is not functioning will be Y liters.
Suppose the chamber volume level after the pump has stopped functioning is Z1 liters. This Z1 liters of liquid is added in the chamber after the pump has stopped functioning, through the casing bridge hole (12). The additional liquid suffices for any minor loss of the liquid after the rotation of the impeller.
So the remaining volume of liquid present in the chamber for priming the pump in the next cycle will be:
Remaining volume for next priming cycle = Y1 – Z1 liters
The final available volume in the chamber when the pump is to be started = Y + (Y1-Z1)
= A1
Thus, the final available fluid priming volume will be A1 liters, which is greater than the actual volume of liquid required for priming the pump i.e. X liters.

The centrifugal self-priming pump with inbuilt reservoir of the present invention is highly advantageous as it eliminates the task of manually filling the pump casing and impeller with the priming liquid before starting the pump. As the quantity of liquid required for priming is already present in the reservoir, as soon as the pump is switched ON, it immediately gets primed and starts pumping the required liquid, thereby saving time. The air vent present on the suction side of the pump removes a large volume of air present, reducing the pump’s workload and increasing its efficiency. The casing bridge hole helps utilize the unused liquid volume in the reservoir, for self-priming the pump during further use. The centrifugal pump impeller reduces the power consumption of the pump. Thus the centrifugal self-priming pump of the present invention is highly advantageous.

Although the preferred embodiment as well as the construction and use have been specifically described, it should be understood that variations in the preferred embodiment could be achieved by a person skilled in the art without departing from the spirit of the invention. The invention has been described with reference to specific embodiments which are merely illustrative and not intended to limit the scope of the invention as defined in the claims.
, Claims:We claim,
1. A centrifugal self-priming pump with inbuilt reservoir which retains the liquid for self-priming itself before use, characterized by a casing chamber (5) with inbuilt reservoir (9), a centrifugal pump impeller (7) present in the casing chamber (5) attached to the shaft (3) of the motor (1) through lantern (4), a spool (6) with air-vent valve (10) on the suction side of the pump and a casing bridge hole (12) present on the inbuilt reservoir (9).
2. The centrifugal self-priming pump with inbuilt reservoir as claimed in claim 1 wherein the motor (1) is connected to the shaft (3) which transmits power and torque to the centrifugal pump impeller (7).
3. The centrifugal self-priming pump with inbuilt reservoir as claimed in claim 1 wherein the shaft (3) is with keyless connection.
4. The centrifugal self-priming pump with inbuilt reservoir as claimed in claim 1 wherein the lantern (4) is a bridge between the motor (1) and pump cover.
5. The centrifugal self-priming pump with inbuilt reservoir as claimed in claim 1 wherein the inbuilt reservoir (9) retains the liquid (13) for priming the pump.
6. The centrifugal self-priming pump with inbuilt reservoir as claimed in claim 1 wherein the liquid in the inbuilt reservoir (9) flows out through the casing inlet and the remaining unused liquid (13) flows through the bridge hole (12) to generate a ring of liquid and allow the air in the pump to escape through the discharge port (8) creating a vacuum near the suction port (11) enabling the flow of the liquid into the pump.
7. The centrifugal self-priming pump with inbuilt reservoir as claimed in claim 1 wherein the air-vent valve (10) on the spool (6) removes the air trapped in the suction pipelines.
8. The centrifugal self-priming pump with inbuilt reservoir as claimed in claim 1 wherein the centrifugal pump impeller (7) in the casing chamber (5) rotates through the energy from the motor (1) and creates a centrifugal force which moves the liquid (13) away from the pump’s center with high velocity and pressure, towards the discharge port (8).