Fluid flow transfer diffuser for a submerged steel pump in fluid

Abstract

The invention of fluid flow transfer diffuser for a submerged steel pump in fluid relates to a centrifugal steel pump with an integrated motor and internal cooling system, in which an innovative diffuser flow guide component has been designed and manufactured. The mentioned diffuser features continuous arcuate channels that effectively guide the output flow from the impeller, reducing the rotational and turbulent components of the fluid, resulting in increased velocity uniformity, improved pressure recovery, and reduced hydraulic losses. This component is seamlessly manufactured from a single metal sheet, without any welding, and is produced solely through cutting, forging, and stamping operations. The pump's compact cylindrical configuration, made from 304 stainless steel and fully sealed with O-rings, ensures reliable operation in submerged. The proposed design enhances hydraulic efficiency by reducing noise and vibration, making it suitable for water supply systems, industrial applications, and process cooling systems.

Description

[0001] TITLE OF THE INVENTION

[0002] FLUID FLOW TRANSFER DIFFUSER FOR A SUBMERGED STEEL PUMP IN FLUID

[0003] TECHNICAL FIELD OF THE INVENTION

[0004] The present invention relates to centrifugal pumps with integrated motors and water cooling systems, as well as components for directing and stabilizing fluid flow and methods for their manufacturing. Specifically, this invention relates to the design and production of a flow guide in the form of a diffuser, positioned before the main pump impeller, which suppresses vortex and turbulence components by creating continuous arcuate channels. This reduces hydraulic losses, improves pressure recovery, and enhances velocity profile uniformity, while the centrifugal flow around the stator facilitates controlled fluid passage for heat dissipation from the motor.

[0005] PRIOR ARTS

[0006] Centrifugal pumps are a very common family of industrial and building pumps, known for their simplicity, affordability, and coverage of a wide range of capacities (from domestic to process applications). These pumps are offered in various configurations: single-stage or multi-stage for higher heads, horizontal or vertical arrangement (end-suction, in-line, vertical multistage), and in conventional or seal-less versions (such as mag-drive and water-cooled “can-motor” for reduced leakage and noise). Construction materials are selected according to the fluid and environment, ranging from cast iron and stainless steel to copper, nickel alloys, andpolymers, while sealing can be achieved with O-rings / mechanical seals or completely seal-less. In general, they are suitable for water and low- viscosity fluids with few particles; for highly viscous fluids or those with coarse solids, other options are usually preferred. In integrated water-cooled designs, the pumped fluid itself is used for heat dissipation, which provides advantages in hygienic and low-noise environments.

[0007] In centrifugal pumps, the impeller discharge inherently has a tangential component and vortex structures which, if not properly guided, cause increased hydraulic losses, noise, vibration, and reduced efficiency. To control this phenomenon, common solutions have included vane-type diffusers, return guide vanes, vortex breaker rings, and flow straightener plates. In the field of motor cooling, two major approaches are seen: the use of an external fan on the motor shaft, or passing the process fluid through an annular channel around the stator in water-cooled pumps. The simultaneous combination of swirl reduction with pressure drop management in order to maintain flow rate remains one of the design challenges in this category of pumps.

[0008] From a manufacturing perspective, many existing diffusers and anti-swirl components are produced in multiple pieces: vanes or baffles are welded to a carrier ring or plate, or the component is produced as a monolithic casting and then machined; in some applications, honeycomb plates or sheet louvers have also been used, typically attached to the body by welding / soldering / riveting. Although these approaches are effective, they generally face issues such as stress concentration and corrosion at weld seams, thermal distortion and difficulty in precise rotordynamic balancing, edge roughness and increased local losses, as well as increased weight and production / assembly cost. Achieving precise control of angles andhydraulic tolerances in mass production is also challenging in welded or fine cast components.

[0009] To improve flow rate and reduce turbulence, some designs add multi-piece guide vanes or flow-straightening plates downstream of the impeller, but edge interference and surface discontinuities in such assemblies can themselves cause flow separation and increased loss coefficient. Furthermore, in water-cooled pumps, the flow guide component is usually designed independently from the cooling path, and structural / hydraulic integration between the anti- swirl element and the cooling path is rarely seen. Therefore, in the current state of the art, there remains a need for a solution that provides a flow guide element with continuous surfaces and without welded joints, so as to both reduce turbulence and swirl and, by reducing hydraulic losses, increase the accessible flow rate at a fixed head, while also being economical and reproducible for sheet-metal mass production. Below, some patents registered in this field are referenced:

[0010] A Chinese invention with Patent No. CN201180680Y, which was granted on 14-01-2009 titled "Stainless steel multi-stage submerged pump", introduces a multistage submersible pump with a full stainless-steel housing, designed to increase durability in corrosive environments and reduce installation space; at the top of the steel housing, the pump cover includes the water outlet, power cable, and handle, and the lower end of the housing is locked with a threaded suction cap; inside the housing, the internal assembly comprises upper and lower bearing supports with the motor positioned between them and sealing O-rings, and beneath the lower support lies the impeller chamber in which several guide vanes / stators are stacked, each carrying its corresponding impeller; these stators are secured with two special screws, and a mechanical seal on the shaft, between the lower support and the stator package, controls leakage; the outcome of this vertical and integratedarrangement is simple installation, stable performance, and longer service life, making the device suitable for industrial, agricultural, and daily water supply applications.

[0011] A Chinese invention with Patent No. CN201739232U, which was granted on 09-02-2011 titled "Submersible pump", describes a submersible pump with a full stainless-steel housing, in which the pump cover accommodates the passage of the power cable, water outlet, and handle, while the housing end is locked by means of a threaded suction cap; within the housing, the internal pump assembly consists of upper and lower bearing supports with sealing O-rings, an electric motor placed between them, and a rotating shaft, and beneath the lower bearing support lies a stator chamber comprising several stacked stators, each mounting an impeller; the stators are secured with special screws, and a mechanical seal on the shaft, located between the lower bearing support and the stator package, restrains leakage; the result of this vertical and integrated arrangement is an innovative design, compact and robust structure, easy installation and operation, small overall size, and wide application range (from industry and agriculture to chemical, pharmaceutical, and municipal water), altogether significantly enhancing the product’s quality and service life.

[0012] A Chinese invention with Patent No. CN203051158U, which was granted on 10-07-2013 titled "Small-size submersible electric pump", describes a small submersible electric pump designed with a stainless- steel housing (alloy lCrl8Ni9Ti with 1.0 mm thickness) and a vertical arrangement of the motor on top and the pumping section at the bottom; on the outer housing, a reinforcing protrusion is provided in the motor section and two protrusions in the pump section, which, together with helical springs positioned between these protrusions and components such as clamps, covers, and water-inlet connectors, ensure preloadand precise axial positioning of the parts; in the sealing section, two O-rings are provided between the upper cover and the housing, and also two mechanical seals between the lower cover of the pumping section and the impeller; the pump base is connected to the housing with a brass nut, and some components (such as covers and base) are made of stainless aluminum alloy; the result of these solutions is a lightweight, compact, and durable structure with reliable sealing, fast heat dissipation, and high corrosion resistance, suitable for operation in aquatic environments with defined acidity or alkalinity.

[0013] A USPTO invention with Patent No. US4923367A, which was granted on 08-05-1990 titled "Submersible pump with plastic housing", describes a multi-stage submersible centrifugal pump with a fully plastic dual-shell housing (two molded body halves) and integrated inlet and outlet heads; the pumping core is in the form of a cartridge of stages (a stack of impeller-diffuser units) mounted on a hexagonal shaft and compressed against an annular shoulder inside the housing by means of an adjusting cone connected to a threaded / adjustable outlet valve assembly, thereby ensuring sealing between stages and eliminating any axial slippage; this cone simultaneously functions as a funnel directing flow to the valve assembly (preferably a poppet valve). The key innovation in the manufacturing method is the use of variable-length molds with a removable / addable central insert, so that the housing length can be adjusted according to the number of stages without the need for multiple molds; the result of this arrangement is reduced weight and production cost, improved integrity and sealing compared to conventional metallic housings, rapid variability in the number of stages, and easy maintenance (e.g., with an external cable guard), all of which enhance the efficiency and application range of multi-stage submersible pumps.A USPTO invention with Patent No. US2086806A, which was granted on 13-07-1937 titled "Deep well centrifugal pump", presents an innovation in the design of multi-stage pumps for extracting water from deep wells. In this system, the pump is placed inside the well and driven by a long shaft connected to a motor at the top of the well. The main problem in older pumps was the heavy weight of the shaft and the extremely high axial load on the bearings, which led to increased costs and energy consumption. This invention successfully reduced stresses on the shaft and axial bearing load by dividing the pump into multiple separate pumping units, gradually reducing the shaft diameter along the downward path, and employing hydraulic balancing rings. The key advantage of this design is that the axial bearing load decreased from about 160,000 pounds to nearly 58,000 pounds, and this savings of more than 100,000 pounds not only reduced the size and cost of the bearings but also increased efficiency, lowered motor power consumption, and extended the overall system’s lifespan. Thus, this invention represents a fundamental advancement in the efficiency and reliability of deep well pumps. A Chinese invention with Patent No. CN211174611U, which was granted on 04-08-2020 titled "Reinforced submersible pump", was designed to address the problems of backflow and efficiency reduction in existing submersible pumps. In this system, the impeller consists of a rotor together with two mounting discs (upper and lower) and a set of blades positioned between these two discs to form a water infusion passageway. During rotor rotation, water enters this passageway from the inlet, and with the help of the blades moves along a U-shaped cross-sectional path between the two discs before rapidly exiting the outlet. This design reduces collision and energy loss caused by the contact of water flow with the inner wall of the housing and minimizes the backflow phenomenon, thereby significantly increasing the pump’ s discharge efficiency. The key advantage of thisinvention lies in simplifying the structure, improving water transfer efficiency, reducing energy losses, and enhancing pump reliability in applications such as domestic water supply, agricultural irrigation, industrial cooling, emergency mine drainage, and even seawater transfer and fountains.

[0014] A Chinese invention with Patent No. CN215566711U, which was granted on 18-01-2022 titled "Axial-flow submersible pump with turbofan", presents a new innovation for improving the efficiency and stability of axial submersible pumps. In this design, in addition to the main impeller, a turbofan is installed inside the pump chamber and close to the impeller. The turbofan blades are designed together with a middle ring, and their tips are connected to the inner wall of the pump outlet. This arrangement provides better guidance of the water flow, reduces fluid friction against the wall, and prevents the formation of swirling flow and vibration in the pump. Furthermore, a diameter-reducing pipe is arranged at the outlet to increase flow velocity, and a strainer (filter) is installed at the inlet to prevent the entry of sludge, sand, and impurities. The key advantage of this invention is the increase of hydraulic efficiency, reduction of the likelihood of impeller and blade failure, savings in maintenance costs, and extension of pump service life. These features enable the pump to operate stably, efficiently, and reliably in harsh environments such as water extraction containing silt or in agricultural and industrial applications.

[0015] A USPTO invention with Patent No. US4973231A, which was granted on 27-11-1990 titled "Submersible pump", provides an innovative solution for enhancing the safety and efficiency of submersible pumps, particularly in evaporative cooling systems. This design includes an electric motor enclosed in a fully isolated chamber, which drives the impeller through magnetic coupling without requiring a shaft to pass through the division wall. To address the problem of motoroverheating, a heat dissipation wall is incorporated, acting as an internal cavity that directs cooling flow from the pump section toward the motor. In addition, a bleed post returns excess water flow from the pump into this cavity and then back to the reservoir, ensuring effective heat exchange. This structure provides several key advantages: prevention of water leakage into the motor (since there is no gland or shaft passage), reduction of motor burn-out risk during hot days, increased durability and safety of the pump, and improved cooling without the need for external equipment. Thus, this invention represents an advanced and efficient design for submersible pumps in applications where stability and thermal protection are critical.

[0016] A Chinese invention with Patent No. CN102536844B, which was granted on 25-09-2013 titled "Stainless steel stamped submersible pump", relates to submersible centrifugal electric pumps and introduces the innovation of replacing cast parts with stainless-steel components manufactured by stamping / deep drawing and welding; specifically, the base, water inlet section, diversion shell, and impeller are all produced using sheet-metal forming and welding processes, reducing the weight of each part to about 0.2-0.3 of the cast equivalent, increasing production efficiency (up to about 5000 units per day compared to 500), and lowering material and energy consumption. In the hydraulic core, a welded sheet-metal impeller with a bladed top plate and funnel-shaped chassis is employed, together with a shaped diversion shell, wear-resistant SiC bearing, and a floating PTFE sealing ring (to ensure alignment and reliable sealing between impeller and diffuser). The mechanical arrangement includes a pump shaft with a series of impeller-diffuser sets, secured with flat tie rods, a stainless- steel filter at the inlet, and a pressurebalancing mechanism at the base (spherical bulge and annular protrusion) to prevent water ingress into the motor and preserve seal life. The result of thesemeasures is a compact structure with reduced overall height, faster and more reliable assembly, higher wear resistance, lower production cost, and greater service durability compared to cast models or plastic / brass impellers.

[0017] A Chinese invention with Patent No. CN218542628U, which was granted on 28-02-2023 titled "Sewage and dirt submersible electric pump", relates to submersible electric pumps for pumping sewage and sludge in the field of fluid machinery and sealing equipment, as well as to connection and sealing structures between the pump body and motor assembly, and to safe and serviceable electrical connection systems in the upper cover. Specifically, this invention concerns the configuration of a pump comprising a body with an impeller and a side-mounted motor assembly sharing a common shaft, a cover equipped with a wiring chamber in which the motor lead is connected to the external cable via a connection cap, body-motor connection by screws with flat washers and an O-ring to ensure sealing, a first mechanical seal on the pump side and a second mechanical seal in the motor’s sealing cavity with provision for oil injection for lubrication, a base with an inlet and several water-passing holes to improve priming, and an outlet fitted with a threaded clamp-type connector for rapid pipe installation and servicing. This field is defined with the objective of enhancing electrical safety, improving maintainability, and increasing sealing stability under heavy-duty sewage operating conditions.

[0018] A Chinese invention with Patent No. CN104121202A, which was granted on 25-08-2017 titled "Steady type high-rotation- speed centrifugal water injection pump", introduces a high-speed, low-flow centrifugal water injection pump for oilfields with high outlet pressure (practical cases up to about 30 MPa with water containing very high chloride ion concentrations). The design features a successive arrangement of suction housing-intermediate housing-final stage housing-guidestators, in which the hydraulic inlet / outlet angle of each stator progressively increases by 10-15 degrees from the first to the last stage, so as to balance hydraulic impacts in all directions and significantly reduce vibration and noise during operation. In the rotor, several impellers are mounted on the shaft with interference fit (hot-fit) and secured with locking rings, while a balancing drum assists axial stability. A set of mechanical seals and left / right bearings support steady operation. To resist severe chloride corrosion under high pressures, the fluid-contacting surfaces of the cover and barrel housing are overlay-clad with stainless steel, while the use of 20MnMo carbon steel for the main body keeps manufacturing costs low. The result is a pump with improved hydraulic balance, reduced vibration and noise, higher durability, and reliable performance for low-flow / high-head water injection in oilfield applications.

[0019] DESCRIPTION OF THE INVENTION

[0020] The present invention relates to a water-cooled centrifugal pump with an integrated motor, specifically to the design of a flow guide component in the form of a diffuser and its manufacturing method. In this design, the process fluid can pass through a circumferential path around the stator for heat absorption, and the diffuser, positioned at the lower part of the main impeller (Fig. 3), suppresses turbulence by creating continuous arcuate channels. The result is a reduction in hydraulic losses and, in many areas, an increase in flow rate. The diffuser is configured to improve pressure recovery and velocity profile uniformity with continuous surfaces, while simultaneously ensuring optimal manufacturability and dynamic balance. In certain preferred embodiments, this diffuser is made from a single metal sheet, without any welding, and is shaped solely through a sequenceof cutting, forging, and stamping operations so that the channels are seamlessly integrated with the body. This proposed configuration, in addition to reducing noise and vibration and simplifying assembly, also facilitates synergy with the internal cooling path.

[0021] The pump of the present invention is mounted horizontally on supports in a compact cylindrical form, with its piping arranged as a side inlet (Fig. 14, No.

[0022] 1401) and top outlet (Fig. 14, No. 1402) integrated into the same cylindrical body (Fig. 13). This housing is sealed at both ends, preventing fluid from entering the interior space. The outer housing and wet parts are preferably made from stainless steel 304 for corrosion resistance and suitability for use in sanitary environments. The internal surfaces are polished and sealed with O-rings to minimize leakage. Additionally, an air vent screw is incorporated into the housing. This design, along with the seamless, weld-free component and internal cooling path, provides a low-noise, low-maintenance configuration suitable for water supply and industrial applications. Depending on the size and the output flow rate of the pump, an appropriate electric motor should be selected.

[0023] In the present invention, the pump is designed as an integrated assembly with an internal motor. The main flow enters the first diffuser unit through the axial inlet. In this unit, an impeller is initially placed, and the flow, after passing through it and then through the guide plate, is accelerated and immediately passes through the diffuser. The arcuate channels in this component reduce the rotational and turbulent components. At the same time, part of the same fluid, in a controlled manner, passes through the main pump impeller, enters the centrifugal cooling path, absorbs heat from the motor, and then exits through the outlet area.Additionally, in this invention, the diffuser unit is placed within a housing in the suction path, before the main impeller. The incoming fluid first passes through the arcuate channels of the diffuser, reducing rotation and turbulence, and then enters the main impeller with a more uniform speed. As a result, less inlet loss, lower noise, and more stable performance are achieved. In another embodiment, this unit is designed modularly, and depending on the project's requirements, one or more diffuser units can be installed in a series arrangement. When more height is needed, adding one or more diffuser units enhances the flow uniformity.

[0024] The impeller plays the main role in transferring energy to the liquid, and by creating a pressure differential, it increases the pressure in the housing, transferring the liquid into the diffuser through the generated pressure. After the impeller, the guide plate and then the diffuser component are placed. This component is the most important and unique part of the pump, responsible for directing the output flow from the impeller, reducing turbulence, and creating a relatively smooth flow in the fluid. This component, made from a plate with appropriate bends, ensures that the fluid flow gains the proper acceleration and direction, preventing energy loss, which optimizes the pump's performance. By increasing the number of these components in the pump, the output pressure of the pump increases.

[0025] The diffuser is made from a metal sheet in a seamless, weld-free design (Fig. 1). In its manufacturing process, a circular plate with a central hole is first cut using one of the processes such as laser cutting, waterjet cutting, or CNC punching. Then, in a cold press with forging operations, reinforcing shapes and soft, diverging edges are created to increase both strength and the smooth entry and exit of the fluid into the channels. Next, semi-complete arcuate slits are formed on the diffuser; these tabs are bent and pushed outward from the plate to create arcuate channels that are seamlessly integrated, with a stable and uniform shape. Afterward, deburring andelectropolishing are carried out to reduce corrosion and roughness, followed by dimensional control, channel angle measurement, balancing, surface uniformity, and roughness testing.

[0026] Overall, the diffuser presented in this invention is a single-piece circular plate with a central hole and several uniform raised arcuate channels around its perimeter. The component is made as a seamless, homogenous part (preferably from stainless steel 304), and there are no weld seams on it.

[0027] In this design, to ensure full sealing of the housing, O-rings are used on the outer wall (at the body / cover connection points) to prevent water from entering the internal assembly. As a result of this environmental sealing, the pump can operate even when submerged, with its internal components remaining protected. This solution, without delving into the specifics of O-ring types or dimensions, aims to reduce leakage and enhance operational safety.

[0028] Additionally, the assembly of the diffuser is such that a set of components, including the diffuser (Fig. 6, No. 603), impeller (Fig. 6, No. 601), and guide plate (Fig. 6, No. 602), are placed within a housing (Fig. 6, No. 604) referred to as the diffuser unit. The guide plate is attached to the diffuser component using spot welding with the help of a flask or argon welding. Depending on the pump's output capacity, the required number of diffuser units can be used. In this case, the diffuser component of the previous unit is welded to the housing of the next diffuser unit (Figs. 16 & 17).

[0029] The electric motor is housed within a housing that is sealed at both ends using caps and O-rings. All moving parts are mounted on a shaft that is connected to the electric motor and two bearings, and they are placed within an outer housing. This outer housing is sealed at both ends using caps and O-rings. The outer housing ismounted on two supports, which are connected and fixed to each other with two threaded rods on either side.

[0030] BRIEF DESCRIPTION OF THE FIGURES

[0031] Figure 1 shows a view of the diffuser component.

[0032] Figure 2 shows a view of the first diffuser unit and the inner housing of the second diffuser unit.

[0033] Figure 3 shows an internal view of the main impeller.

[0034] Figure 4 shows a top view of the guide plate and diffuser, and the inner housing of the second diffuser unit.

[0035] Figure 5 shows internal view of the diffuser unit.

[0036] Figure 6 shows an exploded view of the diffuser unit housing, comprising:

[0037] 601: Impeller

[0038] 602: Guide plate

[0039] 603: Diffuser

[0040] 604: Housing

[0041] Figure 7 shows an assembled view of the internal housings of the pump.

[0042] Figure 8 shows an isometric exploded view of the pump.

[0043] Figure 9 shows an isometric exploded view of the pump.

[0044] Figure 10 shows a side exploded view of the pump.Figure 11 shows a view of the electric motor of the invention.

[0045] Figure 12 shows a view of the supporting bases of the pump.

[0046] Figure 13 shows a side assembled view of the water-cooled centrifugal pump.

[0047] Figure 14 shows a front external view of the water-cooled centrifugal pump, comprising:

[0048] 1401: Inlet

[0049] 1402: Outlet

[0050] Figure 15 shows an isometric assembled view of the invention without the outer housing and motor housing.

[0051] Figure 16 shows an exploded view of the internal components of the invention with three diffuser units.

[0052] Figure 17 shows an exploded view of the diffuser units of a pump with three diffusers.

Claims

WHAT IS CLAIMED IS1. The invention of fluid flow transfer diffuser for a submerged steel pump in fluid includes at least one diffuser unit comprising at least one impeller, at least one guide plate, and at least one diffuser plate, all housed within at least one housing, as well as at least one pump consisting of at least one external housing, at least two supports, at least two threaded rods, at least one electric motor, at least one shaft, at least one bearing, at least two mechanical seals, at least several O-rings, at least several caps, at least one air vent screw, at least one axial inlet, and at least one top outlet.

2. The diffuser according to claim 1 , in which the diffuser is positioned below the main impeller and suppresses turbulence by creating continuous arcuate channels.

3. The diffuser according to claim 1, in which the diffuser is made from a single metal sheet, without any welding, and is formed solely through a sequence of cutting, forging, and stamping operations to ensure that the channels are seamlessly integrated with the body.

4. The diffuser according to claim 1, in which one impeller is placed in the diffuser unit, and the flow, after passing through it and then through the guide plate, is accelerated and immediately passes through the diffuser, where the arcuate channels in this component reduce the rotational and turbulent components.

5. The diffuser according to claim 1, in which the incoming fluid first passes through the arcuate channels of the diffuser, reducing rotation and turbulence, and then enters the main impeller of the pump with a more uniform speed.

6. The diffuser according to claim 1, in which the diffuser unit is designed modularly, and depending on the project’s requirements, one or more diffuser units can be installed in a series arrangement.

7. The diffuser according to claim 1, in which by increasing the height, adding one or more additional diffuser units enhances the flow uniformity.

8. The diffuser according to claim 1, in which the impeller plays the main role in transferring energy to the fluid and, by creating a pressure differential, increases the pressure in the housing and transfers the fluid into the diffuser through the generated pressure.

9. The diffuser according to claim 1, in which the diffuser is cut from a circular plate with a central hole using one of the processes such as laser cutting, water jet cutting, or CNC punching, and then, in a cold press with forging operations, reinforcing shapes and soft, diverging edges are created.

10. The diffuser according to claim 1, in which the guide plate is attached to the diffuser component using spot welding with the help of a flask or argon welding.

11. The diffuser according to claim 1, in which the diffuser component is made as a seamless, homogenous part with the pump (preferably from stainless steel 304), and there are no weld seams on it.

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