Booster pump of reverse osmosis water purifier

Abstract

The invention discloses a booster pump of a reverse osmosis water purifier, and relates to the field of fluid transportation, the booster pump comprises a pump body, a pump cover and a driving shaft driven by a motor, the pump body and the pump cover are enclosed to form a turbine cavity, and the booster pump also comprises a rotor assembly arranged in the turbine cavity; the rotor assembly comprises a main rotor component fixed at one end of the driving shaft, an auxiliary rotor component capable of axially sliding and sleeving the periphery of the main rotor component, a pre-pressing piece for applying an acting force to the auxiliary rotor component to enable the auxiliary rotor component to move along a first direction, and a pressure feedback cavity formed between the auxiliary rotor component and the pump cover; the pressure feedback cavity is in fluid communication with a water outlet channel of the booster pump and used for introducing output pressure of the booster pump into the pressure feedback cavity. According to the booster pump, invalid acting and heating are reduced, internal hydraulic losses such as eddy current and impact losses are greatly reduced, more electric energy is converted into effective pressure energy, and therefore the overall energy efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of fluid transport technology, and more particularly to non-variable volume machinery, specifically a booster pump for a reverse osmosis water purifier. Background Technology

[0002] Reverse osmosis water purification technology is one of the mainstream solutions for obtaining high-quality drinking water. Its core lies in using a reverse osmosis membrane to filter the incoming water. The pores of the reverse osmosis membrane are extremely small, effectively intercepting dissolved salts, heavy metal ions, organic matter, and microorganisms in the water, thus producing pure water. However, due to the extremely high filtration precision of the reverse osmosis membrane, water molecules need to overcome enormous osmotic pressure to pass through the membrane pores. Therefore, a booster pump must be used to provide sufficiently high pressure to the incoming water to drive the water molecules through the membrane. The booster pump thus becomes the heart of the reverse osmosis water purifier.

[0003] In the actual operation of a reverse osmosis water purifier, the booster pump faces two distinct operating conditions. The first is the flushing or high-water-volume condition. At the initial startup of the equipment, or during periodic flushing according to a preset program, a high water flow rate is required to quickly flush the surface of the reverse osmosis membrane and prevent contaminant deposition. At this time, the system pipeline resistance is relatively low, the pump load is small, and the main goal is to provide a large flow rate. The second condition is stable pure water production, which is the operating state of the water purifier for the vast majority of the time. In this state, the resistance of the reverse osmosis membrane is fully manifested, the product water flow rate is very small, typically only tens to hundreds of milliliters per minute, and the discharge of concentrated water is also limited by the wastewater proportioning valve. The pump essentially operates continuously under high back pressure and extremely low flow rate, and its core task is to maintain a stable high output pressure.

[0004] In existing technologies, reverse osmosis water purifiers generally use a single-stage centrifugal booster pump as the core power component. This type of pump has a simple structure and low cost. Its working principle relies on a high-speed rotating impeller to transfer mechanical energy to the liquid, thereby increasing the liquid's pressure and flow rate. When designing a single-stage centrifugal pump, its hydraulic components are optimized for a specific combination of flow rate and head. Near this operating point, the pump's efficiency reaches its maximum, forming the peak region of a parabolic efficiency curve.

[0005] However, applying this fixed-characteristic single-stage centrifugal pump to a reverse osmosis water purification system with drastic fluctuations in operating conditions reveals significant drawbacks. Under high-flow conditions such as flushing or large-volume water use, the pump's actual operating point remains close to its high-efficiency range. But once it enters low-flow pure water production mode, the pump's hydraulic efficiency drops sharply. At this point, most of the input electrical energy is not converted into effective pressure energy, but is consumed in the internal friction and eddy current losses of the water flow, ultimately converting into heat energy, causing the pump body and internal water temperature to rise. This operating state not only results in a significant waste of electrical energy, but the prolonged high-temperature environment also accelerates the aging process of the plastic components inside the pump, promotes the formation of scale from minerals in the water inside the pump body, and may even affect the outlet water temperature, reducing the user experience. Summary of the Invention

[0006] This invention overcomes the shortcomings of the prior art and provides a booster pump for a reverse osmosis water purifier. By modifying the structure of the booster pump rotor, the pump's fluid dynamic components can adapt to the two drastically different operating conditions of the reverse osmosis water purifier, namely large and small flow rates. Under the condition of producing pure water at a small flow rate, it effectively improves energy efficiency, reduces ineffective work and heat generation, thereby solving the problem of efficiency imbalance of traditional booster pumps under different operating conditions.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The present invention provides a booster pump for a reverse osmosis water purifier, including a pump body, a pump cover, and a drive shaft driven by a motor, wherein the pump body and the pump cover enclose a turbine cavity, and further includes a rotor assembly disposed within the turbine cavity;

[0008] The rotor assembly includes: a main rotor component fixed to one end of the drive shaft, an auxiliary rotor component that can slide axially and is fitted around the main rotor component, a preload member that applies a force to the auxiliary rotor component to move it in a first direction, and a pressure feedback chamber formed between the auxiliary rotor component and the pump cover.

[0009] The pressure feedback chamber is in fluid communication with the outlet channel of the booster pump, and is used to introduce the output pressure of the booster pump into the pressure feedback chamber.

[0010] The auxiliary rotor component is used to move axially under the combined action of the pressure in the pressure feedback chamber and the force of the pre-pressurization component, so as to change the cross-sectional area of ​​the water flow channel formed by the main rotor component and the auxiliary rotor component.

[0011] In a preferred embodiment of the present invention, the main rotor component includes a main turbine disk, the main turbine disk having a plurality of main blades extending axially toward the water inlet channel of the booster pump; the auxiliary rotor component includes an auxiliary turbine ring, the auxiliary turbine ring having a plurality of auxiliary blades on one side toward the main turbine disk; the auxiliary blades and the main blades are staggered in the axial direction.

[0012] In a preferred embodiment of the present invention, a plurality of receiving grooves are provided on the side of the main turbine disk, and the secondary blades are slidably engaged with the inner side of the receiving grooves.

[0013] In a preferred embodiment of the present invention, a plurality of piston-shaped shoulders are fixed on the side of the auxiliary turbine ring facing the pump cover; an annular cavity is provided on the inner side of the pump cover; the piston-shaped shoulders and the annular cavity cooperate to form the pressure feedback cavity.

[0014] In a preferred embodiment of the present invention, a pressure sensing hole is provided at the bottom end of the annular cavity, and the pressure sensing hole is connected to the water outlet channel through the internal flow channel of the pump cover.

[0015] In a preferred embodiment of the present invention, the adaptive rotor assembly further includes a guide structure, the guide structure including a plurality of guide pins fixed to the side of the main turbine disk and an axial straight groove formed on the inner hole side of the auxiliary turbine ring; the guide pins and the axial straight groove are slidably engaged to limit the rotation of the auxiliary turbine ring relative to the main turbine disk.

[0016] In a preferred embodiment of the present invention, the number of secondary blades is the same as the number of primary blades, or is an integer multiple of the number of primary blades; both the primary blades and the secondary blades are circumferentially uniformly distributed.

[0017] In a preferred embodiment of the present invention, the preload component is a helical spring, one end of which is fixed to a spring seat on the back of the main rotor component, and the other end is fixed to the side of the auxiliary rotor component.

[0018] In a preferred embodiment of the present invention, the first direction is the direction in which the auxiliary rotor component moves toward the pump cover.

[0019] In a preferred embodiment of the present invention, the main rotor component is connected to the drive shaft by a key.

[0020] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0021] (1) The present invention provides a booster pump for a reverse osmosis water purifier, which adopts an adaptive rotor assembly. The auxiliary rotor component can move axially according to the system output pressure to change the cross-sectional area of ​​the water flow channel. When the system is under different working conditions, the pressure in the pressure feedback chamber will change with the pump output pressure, which can drive the auxiliary rotor component to slide axially, change the axial overlap of the main and auxiliary blades, and adjust the flow channel cross section and blade density of the pump. In this way, the pump's fluid power component can adapt to the flow demand of different working conditions. It can also maintain high hydraulic efficiency under low flow pure water production conditions. Compared with the traditional single-stage centrifugal pump, which has a fixed highest efficiency point, once the operating point deviates from the design value, the hydraulic efficiency will drop sharply, and most of the electrical energy will be converted into heat energy and wasted. The booster pump of the present invention not only reduces ineffective work and heat generation, but also significantly reduces internal hydraulic losses such as eddy current and impact losses, converting more electrical energy into effective pressure energy, thereby improving the overall energy efficiency.

[0022] (2) The adaptive adjustment mechanism of the booster pump in this invention can reduce the ineffective work done by the pump under low flow conditions. As the hydraulic loss is reduced after the flow channel narrows, the amount of electrical energy converted into heat energy is also reduced accordingly. The temperature rise of the pump body and its internal circulating water is effectively controlled. At the same time, the pump is prevented from operating under extreme pressure for a long time, making the operating point closer to the high efficiency zone. This can reduce the mechanical load and thermal stress of the impeller and motor, which not only helps to protect the sealing materials and plastic parts inside the pump and delay aging, but also effectively extends the overall service life and reliability of the booster pump.

[0023] (3) In this invention, by connecting the pressure feedback chamber with the water outlet channel, the adjustment process can be continuous and automatic. When the system pressure changes, the position of the auxiliary rotor component is finely adjusted to adapt to the flow demand in real time. As a result, the inlet water pressure in front of the reverse osmosis membrane remains relatively stable. Compared with the fixed impeller pump, the pressure fluctuation is large when the flow changes. The booster pump of this invention can effectively ensure the water production efficiency and water quality consistency of the reverse osmosis membrane.

[0024] (4) In this invention, the rotor assembly is based on a purely mechanical structure, without the need for electronic sensors or controllers. It relies on the system's own pressure to drive the movement of the auxiliary rotor components, and the pre-pressurized components provide the reset force. It can achieve fully adaptive working condition matching, effectively avoiding increased costs and failure points. Its booster pump has a compact structure, limited cost increase, simple maintenance, and high reliability. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a three-dimensional structural diagram of the booster pump according to a preferred embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of a half-section of the booster pump according to a preferred embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the distribution structure of the main blades and auxiliary blades in a preferred embodiment of the present invention;

[0029] Figure 4 This is a preferred embodiment of the present invention. Figure 2 Enlarged structural diagram at point A in the middle;

[0030] Figure 5 This is a preferred embodiment of the present invention. Figure 2 Enlarged structural diagram at point B;

[0031] In the diagram: 1. Pump body; 11. Pump cover; 111. Annular cavity; 12. Drive shaft; 13. Inlet channel; 14. Outlet channel; 2. Main turbine disk; 21. Main blade; 22. Receiving groove; 3. Secondary turbine ring; 31. Secondary blade; 32. Piston-shaped shoulder; 4. Pre-compression component; 41. Helical spring; 5. Pressure feedback chamber; 51. Pressure sensing hole; 6. Guide pin; 7. Spring seat. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0034] In the description of this application, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "axial," "radial," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0035] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0036] This invention provides a booster pump for a reverse osmosis water purifier, comprising a pump body 1, a pump cover 11, and a drive shaft 12 driven by a motor. The pump body 1 and the pump cover 11 enclose a turbine cavity, and the pump body 1 and the pump cover 11 further comprise a rotor assembly disposed within the turbine cavity. The rotor assembly comprises a main rotor component fixed to one end of the drive shaft 12, an auxiliary rotor component that is axially slidable and fitted around the main rotor component, a pre-compression member 4 that applies a force to the auxiliary rotor component to move it in a first direction, and a pressure feedback chamber 5 formed between the auxiliary rotor component and the pump cover 11. The pressure feedback chamber 5 is in fluid communication with the outlet channel 14 of the booster pump and is used to introduce the output pressure of the booster pump into the pressure feedback chamber 5. The auxiliary rotor component is used to move axially under the combined action of the pressure in the pressure feedback chamber 5 and the force of the pre-compression member 4 to change the cross-sectional area of ​​the water flow channel formed by the main rotor component and the auxiliary rotor component.

[0037] This invention integrates an axially sliding auxiliary rotor component with a pressure feedback chamber 5 into the rotor assembly, enabling the pump's flow channel cross-section to adaptively adjust with system pressure. The basic principle is as follows: When the system is under low back pressure and high flow conditions, the pressure feedback chamber 5 has a lower pressure, and the pre-compression component 4 pushes the auxiliary rotor component forward, causing the main and auxiliary blades 31 to overlap, forming a turbine with a wide flow channel and high blade density to meet high flow demands. When the system enters a high back pressure and low flow condition, the outlet water pressure acts on the auxiliary rotor component through the pressure feedback chamber 5, pushing it backward, narrowing the flow channel, reducing the effective working area of ​​the blades, and bringing the pump's operating point closer to the high-head, low-flow, high-efficiency zone, thereby significantly reducing hydraulic losses, improving energy efficiency, and reducing heat generation. This structure relies entirely on the system's own pressure to achieve purely mechanical adaptive adjustment, requiring no external control.

[0038] The following will describe in detail, with reference to the accompanying drawings and several embodiments, the specific implementation of the above core concept, the structure of each component, the connection relationship and their collaborative working process.

[0039] Example 1:

[0040] Combination Figure 1 and Figure 2 As shown, this embodiment provides a booster pump for a reverse osmosis water purifier; the pump body 1 and the pump cover 11 are fastened together by bolts, forming a sealed turbine chamber. The drive shaft 12 passes through the shaft seal at the rear of the pump body 1 and extends into the turbine chamber, and is driven to rotate by an external motor. The pump body 1 is provided with an inlet channel 13 and an outlet channel 14. The inlet channel 13 extends axially towards the center of the turbine chamber, and the outlet channel 14 extends tangentially from the outer periphery of the turbine chamber.

[0041] It should be noted that the pump body 1 and pump cover 11 are made of reinforced engineering plastic, preferably PPS or PA66+GF injection molded, with smooth internal flow channels to reduce flow loss. The drive shaft 12 and the motor output shaft can be connected via a coupling or directly to ensure reliable power transmission.

[0042] The core improvement of this embodiment lies in the installation of a rotor assembly within the turbine cavity. This assembly mainly includes a main rotor component, an auxiliary rotor component, a pre-compression component 4, and a pressure feedback chamber 5 formed by the auxiliary rotor component and the pump cover 11. Its basic principle is to automatically change the axial position of the auxiliary rotor component by utilizing changes in the system output pressure, thereby adjusting the effective cross-sectional area and blade density of the water flow channel formed by the main and auxiliary blades 31, allowing the pump's performance curve to adapt to different operating conditions.

[0043] Specifically, the main rotor component is the main turbine disk 2 fixed to the end of the drive shaft 12. The main turbine disk 2 is injection molded in one piece, and its hub has a keyed shaft hole in the center. It is circumferentially fixed to the drive shaft 12 by a flat key, ensuring synchronous rotation. (Refer to...) Figure 3As shown, the main turbine disk 2 extends radially from the front of the water inlet channel 13, with several main blades 21 extending axially and evenly distributed circumferentially. The side of the main turbine disk 2, i.e. the cylindrical surface where the blade roots are located, has several axially extending receiving grooves 22. The number of receiving grooves 22 corresponds to the number of secondary blades 31, and their circumferential positions are staggered with those of the main blades 21.

[0044] Furthermore, the auxiliary rotor component is an annular auxiliary turbine ring 3, fitted around the periphery of the main turbine disk 2. The inner diameter of the auxiliary turbine ring 3 is slightly larger than the outer diameter of the main turbine disk 2, allowing it to slide axially along the main turbine disk 2. The auxiliary turbine ring 3 has several integrally formed auxiliary blades 31 facing the main turbine disk 2. The number of auxiliary blades 31 can be the same as or an integer multiple of the number of main blades 21, and they are also circumferentially evenly distributed. The inner ends of the auxiliary blades 31 slide into the receiving grooves 22 on the side of the main turbine disk 2, achieving circumferential linkage and axial sliding guidance between the two. The front side of the auxiliary turbine ring 3, i.e., the side facing the pump cover 11, has several piston-shaped shoulders 32, which are evenly distributed circumferentially.

[0045] Furthermore, referring to Figure 4 As shown, an annular boss is machined on the inner side of the pump cover 11, i.e., the side facing the turbine cavity. An annular cavity 111 is provided on the inner side of the boss corresponding to the position of the piston-shaped shoulder 32. When the auxiliary turbine ring 3 is pushed to the foremost position, its piston-shaped shoulder 32 is precisely embedded in the annular cavity 111, and the two cooperate to form a pressure feedback chamber 5 that can change with pressure. Several tiny pressure sensing holes 51 are opened at the bottom of the annular cavity 111. These holes are connected to the pump's water outlet channel 14 through a small flow channel machined inside the pump cover 11, thereby introducing the pump's real-time output pressure into the pressure feedback chamber 5.

[0046] In this embodiment, refer to Figure 5 As shown, the preload component 4 is a helical spring 41, which is installed between the spring seat 7 specially set on the back of the main turbine disk 2 and the back of the auxiliary turbine ring 3. The spring is always in a compressed state, and its elastic force is directed to push the auxiliary turbine ring 3 toward the pump cover 11, that is, to move it forward.

[0047] Understandably, the preload of the spring needs to be designed and calculated to balance the hydraulic thrust generated by the pressure feedback chamber 5 under different pressures, thereby achieving automatic adjustment of the position of the auxiliary rotor components.

[0048] For example, the calibration method for spring preload design calculation includes the following steps:

[0049] S1. Determine the system design switching pressure point: Based on the operating characteristics of the reverse osmosis membrane and the system design, determine the initial pressure point at which the system needs to switch from high-flow-rate mode to low-flow-rate mode; set the pressure point P. s=0.3 MPa means that when the system pressure is below 0.3 MPa, the pump should maintain the compound large impeller state; when the pressure reaches and exceeds 0.3 MPa, the auxiliary turbine ring 3 should begin to move backward.

[0050] S2. Calculate the required hydraulic thrust: Measure or calculate the effective pressure-bearing area A of the piston-shaped shoulder 32 on the auxiliary turbine ring 3. p By measuring the inner diameter D of the annular cavity 111 i and outer diameter D o Calculate the area of ​​the annulus:

[0051] A p =π×((D o / 2) 2 – (D i / 2) 2 ).

[0052] Assuming A is calculated p =50 mm 2 =5×10 -5 m 2 .

[0053] At the switching point, the required hydraulic thrust is: F p,s =P s ×A p =0.3×10 6 Pa×5×10 -5 m 2 =15 N.

[0054] S3. Determine the target preload of the spring: Theoretically, the preload F should be satisfied at the switching point. s,i =Hydraulic thrust F p,s .

[0055] However, frictional force F must be considered. f And design margin. Friction includes sliding friction between the auxiliary turbine ring 3 and the main turbine disk 2, and between the guide pin 6 and the straight groove. It can be estimated by the material friction coefficient or determined experimentally.

[0056] Assuming the estimated total sliding friction is approximately 2 N, and desiring a clear switch, we add a margin of approximately 10%.

[0057] The revised design value for spring preload is: F s,d =F p,s +F f +Margin ≈ 15 N + 2 N + (15 N × 10%) = 18.5 N.

[0058] S4. Spring Selection and Parameter Determination: Determine the free length L of the spring based on the installation space, i.e., the initial clearance between the spring seat 7 and the auxiliary turbine ring 3.f and the maximum allowable working compression ΔL max .

[0059] According to Hooke's Law, the spring force F = k × Δx, where k is the spring stiffness and Δx is the compression.

[0060] The spring is set to have an initial pre-compression ΔL after installation. i The force generated at this time is the required preload F. s,d (For example, 18.5 N). That is: k × ΔL i = 18.5 N.

[0061] At the same time, the spring needs to allow the secondary turbine ring to continue to be compressed for a stroke ΔL under the maximum system pressure, such as 0.8 MPa. w The corresponding maximum hydraulic thrust F p,m =0.8×10 6 Pa×5×10 -5 m 2 = 40 N. The total compression of the spring at this point is ΔL. i +ΔL w The elastic force is k × (ΔL) i +ΔL w ).

[0062] At the new equilibrium point, the following should be satisfied: k × (ΔL) i +ΔL w ) + F f ≈ F p,m .

[0063] Solve the above equations simultaneously, and combine them with the spatial constraints (ΔL). i +ΔL w ≤ ΔL max The appropriate spring stiffness k and initial precompression ΔL can then be solved. i and work journey ΔL w .

[0064] S5. The above calculations are theoretical calibrations. During the sample stage, actual verification using a pressure testing bench is required. Monitor whether the displacement of the auxiliary turbine ring 3 matches the design curve under different system pressures, and whether the pump's flow-pressure-efficiency curve is optimized at the expected operating point.

[0065] Based on the measured friction and pressure feedback, it may be necessary to fine-tune the spring pre-compression (by adjusting the thickness of the spring seat 7 shim) or stiffness to accurately match the target switching pressure and adjust linearity.

[0066] As a preferred embodiment of this invention, to ensure that the secondary turbine ring 3 can only slide axially and cannot rotate relative to the main turbine disk 2, this embodiment also includes a guide anti-rotation structure. Specifically, at least two guide pins 6 are fixed to the side of the main turbine disk 2, and correspondingly, an axial straight groove (not shown in the figure) equal in number to the guide pins 6 is machined on the inner wall of the secondary turbine ring 3. The guide pins 6 slide within the axial straight grooves, allowing the secondary turbine ring 3 to move axially while constraining it to rotate synchronously with the main turbine disk 2.

[0067] In the booster pump of Example 1, its operation is entirely controlled by the system output pressure, i.e., the back pressure is automatically regulated, requiring no external intervention. The dynamic coordination and working principle between the various structural features under two typical operating conditions will be described in detail below.

[0068] High flow rate operation: When the water purification system is started, or is in a state of timed flushing or large user water usage, the pressure difference before and after the reverse osmosis membrane is small, the pipeline system resistance is low, which results in the pump needing to maintain a lower output pressure, usually below 0.2 MPa.

[0069] The output pressure generated during pump operation is introduced in real time into the pressure feedback chamber 5, which is formed by the piston-shaped shoulder 32 of the auxiliary turbine ring 3 and the annular cavity 111 of the pump cover 11, through the flow channel inside the pump cover 11 and the pressure sensing hole 51. Under this condition, due to the low system pressure, the hydraulic thrust acting on the effective area of ​​the piston-shaped shoulder 32 is small; at this time, the hydraulic thrust is less than the forward force of the helical spring 41 preloaded between the spring seat 7 and the auxiliary turbine ring 3. According to the principle of mechanical balance, the net external force pushes the auxiliary turbine ring 3 forward against sliding friction, that is, towards the pump cover 11. The pre-compression force of the helical spring 41 pushes it to the foremost end of its axial stroke.

[0070] When the auxiliary turbine ring 3 is at its foremost position, its inner auxiliary blades 31 extend to their maximum extent from the receiving groove 22 of the main turbine disk 2, causing the main blades 21 and auxiliary blades 31 to form a large overlap area in the axial direction. The blades are arranged in an alternating pattern, forming a composite impeller with a large inlet flow area and high blade density. The water flowing axially from the inlet channel 13 can be fully captured and accelerated by the composite impeller with its dense blades. The impeller geometry in this state is similar to that of a high specific speed centrifugal impeller. Its optimized operating point corresponds to a high flow rate and a medium head. The water flows smoothly in the wide flow channel, and the blade angle is reasonable, so eddy current loss and flow separation are minimal. The pump can efficiently convert the mechanical energy input from the motor into the kinetic and pressure energy of the water, thereby meeting the system's requirements for high flow rate, rapid water flow, or scouring of the membrane surface. The cooperation between the guide pin 6 and the axial straight groove ensures that the auxiliary turbine ring 3 and the main turbine disk 2 rotate in absolute synchronous motion, avoiding vibration or disturbance that may be caused by the speed difference of the sliding parts.

[0071] Working process under low flow conditions: When the water purifier enters a stable water production mode, the reverse osmosis membrane generates extremely high resistance to the water flow. In order to drive trace water molecules through the membrane pores, the system needs a pump to maintain a high pressure, while the water production flow rate is only tens to hundreds of milliliters per minute.

[0072] The system pressure rises sharply, and the same pressure is instantly transmitted to the pressure feedback chamber 5 through the pressure sensing hole 51. The hydraulic thrust acting on the piston-shaped shoulder 32 increases proportionally. When the hydraulic thrust exceeds the preload of the helical spring 41, the force balance is broken. Under the action of the reverse hydraulic thrust, the auxiliary turbine ring 3 begins to compress the helical spring 41 and slides smoothly backward along the guide structure, i.e., in the direction of the motor. This is a continuous dynamic adjustment process, and the position of the auxiliary turbine ring 3 will eventually stabilize at a new equilibrium point where the hydraulic thrust equals the preload. The higher the system pressure, the greater its backward sliding displacement.

[0073] As the secondary turbine ring 3 moves backward, its secondary blades 31 gradually retract into the receiving groove 22 of the main turbine disk 2, resulting in a significant reduction in the effective overlap area of ​​the main and secondary blades 31 in the axial direction. This produces two hydraulic effects: First, the effective flow cross-sectional area of ​​the water flow from the impeller inlet to the outlet continuously narrows, which can increase the flow velocity in the flow channel and change the distribution of the flow field; second, the main blades that do work on the water flow gradually become the main blades 21 on the main turbine disk 2, and the secondary blades 31 gradually withdraw from the main work area.

[0074] Its adaptive adjustment structure essentially switches the impeller's operating mode from high flow rate, low head characteristics to low flow rate, high head characteristics. The narrowed flow channel allows the water flow at low flow rates to better conform to the profile of the main blade 21, thereby significantly reducing the large-scale eddies, secondary flows, and inlet impact losses that would inevitably occur under wide flow channel, low flow conditions. The design of the main blade 21 can be optimized separately for such high back pressure, low flow conditions. Therefore, the pump's actual operating point is automatically pulled back to or close to the high-efficiency zone of the main blade 21 under this condition, thus converting a larger proportion of the input electrical energy into effective pressure energy, rather than useless heat energy. The guide structure ensures that the impeller's dynamic balance is not disrupted during adjustment, and the friction damping of the sliding surface is also designed to be at a low level to ensure the sensitivity and reliability of adjustment.

[0075] Example 2:

[0076] Based on Example 1, this example further optimizes the specific structure of the pressure feedback chamber 5 and the pressure transmission path to improve adjustment sensitivity and reliability.

[0077] Specifically, the piston-shaped shoulder 32 on the front of the secondary turbine ring 3 can be designed with different cross-sectional shapes, such as rectangular, trapezoidal, or semi-circular, to optimize its sliding characteristics with the annular cavity 111. The depth of the annular cavity 111 is slightly greater than the height of the piston-shaped shoulder 32, ensuring that the shoulder of the secondary turbine ring 3 always slides within the cavity and maintains an effective pressure seal throughout the entire sliding stroke.

[0078] Furthermore, several pressure sensing holes 51 can be formed at the center of the bottom of the annular cavity 111, with a preferred diameter of 0.5-1.5 mm. Too small a diameter may cause sluggish response, while too large a diameter may cause pressure fluctuations in the pressure chamber. The flow channel (not shown in the figure) inside the pump cover 11 used to connect the pressure sensing holes 51 to the water outlet channel 14 is a short and straight path to minimize flow resistance and pressure loss, ensuring the real-time performance and accuracy of pressure feedback.

[0079] Optionally, in order to protect the mechanism under extreme high pressure, a mechanical limiting structure, such as a short flange, can be provided at the edge of the annular cavity 111 of the pump cover 11. When the auxiliary turbine ring 3 slides backward to the limit position, corresponding to the minimum flow channel section, the root of its piston-shaped shoulder 32 or the body of the auxiliary turbine ring 3 contacts the limiting structure, preventing the spring from being over-compressed and failing, and also avoiding mechanical interference.

[0080] This embodiment optimizes the pressure feedback chamber 5, making the conversion of system pressure to axial thrust more linear, sensitive, and reliable. This ensures that the pressure sensing and transmission path guarantees that the auxiliary rotor component can respond quickly to subtle changes in water usage, thereby achieving high stability of the reverse osmosis membrane inlet water pressure. Furthermore, the design based on the fluid pressure itself for precise mechanical feedback eliminates the need for sensors and controllers, thus achieving high-precision adaptive adjustment at low cost.

[0081] Example 3:

[0082] Based on Embodiment 1 or 2, this embodiment modifies the guide anti-rotation structure and introduces an auxiliary seal to further improve the stability of the sliding pair and prevent internal leakage.

[0083] Specifically, the guide structure can forgo the fit between the guide pin 6 and the straight groove, and instead employ an equivalent method: at least two raised guide ridges, or sliding keys, are machined axially on the outer cylindrical surface of the main turbine disk 2. Correspondingly, an axial keyway matching the guide ridges is machined on the inner wall of the secondary turbine ring 3. The sliding fit between the guide ridges and the keyway can also restrict circumferential relative rotation and guide axial movement. The integrally formed guide structure has better machinability and strength.

[0084] Furthermore, considering the relative sliding gap between the auxiliary turbine ring 3 and the main turbine disk 2, in order to prevent high-pressure water from leaking from the turbine cavity through this gap to the low-pressure area, affecting the adjustment accuracy and pump efficiency, this embodiment can set a simple dynamic seal between the two.

[0085] For example, an annular groove can be formed on the main turbine disk 2, and an O-ring can be placed in the groove. The outer diameter of the O-ring maintains sliding sealing contact with the inner hole of the auxiliary turbine ring 3. Alternatively, a groove can be formed in the inner hole of the auxiliary turbine ring 3 and a sealing ring can be placed there. The sealing ring material can be selected from water-resistant, temperature-resistant and wear-resistant rubber, preferably EPDM or fluororubber.

[0086] This embodiment enhances the mechanical stability and sealing reliability of the adaptive rotor assembly under long-term high-speed rotation and frequent axial sliding conditions by optimizing the guide structure and introducing auxiliary seals. The stable guide avoids possible swaying or jamming of the auxiliary turbine ring 3, ensuring its smooth axial movement; the effective dynamic seal reduces internal leakage loss, allowing more water flow energy to be used for effective work, thereby improving the overall efficiency of the pump.

[0087] Example 4:

[0088] Based on any of the above embodiments, this embodiment provides an alternative to the form and installation method of the pre-compression component 4.

[0089] It should be noted that the function of the preload element 4 is to provide the restoring force that moves the auxiliary rotor component forward and to set a threshold for balancing with the system pressure. Besides the helical spring 41, other elastic elements can also be used for the preload element 4.

[0090] For example, a set of circumferentially distributed disc springs, i.e., stacked Belleville springs, are installed between the spring seat 7 and the auxiliary turbine ring 3. Disc springs can provide greater elastic force in a smaller space, and their force-displacement characteristics may better meet design requirements.

[0091] Alternatively, the preload element 4 may not be a discrete spring, but rather utilize the elastic material itself. For example, an annular elastic rubber or silicone body with a preset compression can be filled between the back of the auxiliary turbine ring 3 and the annular boss of the pump cover 11. This elastomer provides elasticity and may also assist in providing a certain degree of sealing and cushioning.

[0092] Specifically, if an elastomer solution is adopted, the annular elastomer can be vulcanized and bonded around the annular cavity 111 of the pump cover 11, and then tightly attached to the back of the auxiliary turbine ring 3 after assembly. Its compression and elastic modulus need to be designed to match the pressure regulation threshold required by the system.

[0093] This embodiment demonstrates different means of achieving the pre-compression function. Whether it is a metal spring or an elastic polymer, as long as it can provide a controllable reset force that is balanced with the system pressure and works in conjunction with core features such as the pressure feedback chamber 5 and the sliding rotor, it falls within the protection concept of this invention.

[0094] The above description is based on the preferred embodiments of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of the invention is defined by the appended claims rather than the foregoing description, and all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0095] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A booster pump for a reverse osmosis water purifier, comprising: The pump body, pump cover, and drive shaft driven by a motor, wherein the pump body and the pump cover enclose a turbine cavity, characterized in that it further includes: a rotor assembly disposed within the turbine cavity; The rotor assembly includes: a main rotor component fixed to one end of the drive shaft, an auxiliary rotor component that can slide axially and is fitted around the main rotor component, a preload member that applies a force to the auxiliary rotor component to move it in a first direction, and a pressure feedback chamber formed between the auxiliary rotor component and the pump cover. The pressure feedback chamber is in fluid communication with the outlet channel of the booster pump, and is used to introduce the output pressure of the booster pump into the pressure feedback chamber. The auxiliary rotor component is used to move axially under the combined action of the pressure in the pressure feedback chamber and the force of the pre-pressurization component, so as to change the cross-sectional area of ​​the water flow channel formed by the main rotor component and the auxiliary rotor component.

2. The booster pump for a reverse osmosis water purifier according to claim 1, characterized in that: The main rotor assembly includes a main turbine disk, which has a plurality of main blades extending axially toward the water inlet channel of the booster pump; the auxiliary rotor assembly includes an auxiliary turbine ring, which has a plurality of auxiliary blades on one side toward the main turbine disk; the auxiliary blades and the main blades are staggered in the axial direction.

3. The booster pump for a reverse osmosis water purifier according to claim 2, characterized in that: The main turbine disk has several receiving slots on its side, and the secondary blades are slidably engaged with the inside of the receiving slots.

4. The booster pump for a reverse osmosis water purifier according to claim 2, characterized in that: The auxiliary turbine ring has several piston-shaped shoulders fixed on the side facing the pump cover; the inner side of the pump cover is provided with an annular cavity; the piston-shaped shoulders and the annular cavity cooperate to form the pressure feedback chamber.

5. The booster pump for a reverse osmosis water purifier according to claim 4, characterized in that: A pressure sensing hole is provided at the bottom of the annular cavity, and the pressure sensing hole is connected to the water outlet channel through the internal flow channel of the pump cover.

6. The booster pump for a reverse osmosis water purifier according to claim 2, characterized in that: The adaptive rotor assembly also includes a guide structure, which includes a plurality of guide pins fixed to the side of the main turbine disk and an axial straight groove formed on the inner hole side of the auxiliary turbine ring; the guide pins and the axial straight groove are slidably engaged to limit the rotation of the auxiliary turbine ring relative to the main turbine disk.

7. The booster pump for a reverse osmosis water purifier according to claim 2, characterized in that: The number of secondary blades is the same as the number of primary blades, or is an integer multiple of the number of primary blades; both primary blades and secondary blades are circumferentially evenly distributed.

8. The booster pump for a reverse osmosis water purifier according to claim 1, characterized in that: The preload component is a helical spring, one end of which is fixed to a spring seat on the back of the main rotor component, and the other end is fixed to the side of the auxiliary rotor component.

9. The booster pump for a reverse osmosis water purifier according to claim 1, characterized in that: The first direction is the direction in which the auxiliary rotor component moves toward the pump cover.

10. The booster pump for a reverse osmosis water purifier according to claim 1, characterized in that: The main rotor component is connected to the drive shaft by a key.

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