Dynamic circulating valve capable of automatically adjusting jet flow

Abstract

The invention discloses an automatic jet flow adjusting dynamic circulating valve which comprises a valve body. The nozzle is provided with a spraying hole; the spraying needle movably penetrates through the spraying hole in the axis direction of the nozzle, and the spraying needle comprises a needle head section which is sleeved with an adjusting spring; the needle tail section comprises a forward conical section, and the diameter of the forward conical section is gradually increased from the needle head section to the needle tail section; when the fluid pressure of the main water inlet is increased, the high-pressure fluid compresses the adjusting spring and pushes the spray needle to move towards the mixed water outlet, the gap between the positive conical section and the inner wall of the spray hole is increased, negative pressure formed at the communicating water inlet is accelerated, and negative pressure injection is strengthened; when the fluid pressure of the main water inlet is reduced, the adjusting spring rebounds to drive the spray needle to move towards the main water inlet, the gap between the forward conical section of the needle tail and the inner wall of the spray hole is reduced, and negative pressure injection is weakened. The adjusting spring is arranged on the spray needle, and automatic adjustment can be achieved according to the fluid pressure of the main water inlet.

Description

Technical Field

[0001] The present invention relates to the technical field of mixing valves. More specifically, the present invention relates to an automatic regulating jet dynamic circulation valve. Background Art

[0002] For the building water supply and drainage system, pressure balance is crucial. Usually, a jet device (such as a jet valve including structures such as a nozzle and a needle) is used for water pressure regulation. However, when the existing jet valve faces changes in water usage conditions on different floors, relying on a fixed aperture design, it is necessary to manually adjust the position of the needle to adapt to pressure fluctuations and cannot automatically adjust to maintain a stable water pressure. If the adjustment is not timely, low-floor users may experience problems such as excessive water flow and easy damage to pipes due to too high water pressure during long-term use, while high-floor users may face difficulties in using water due to insufficient water pressure during long-term use, seriously affecting the user experience and being unfavorable to the long-term stable operation of the building water supply and drainage system. Therefore, there is an urgent practical need to develop a jet valve that can automatically adjust to achieve efficient, energy-saving, and stable fluid management. Summary of the Invention

[0003] An object of the present invention is to provide an automatic regulating jet dynamic circulation valve, including: A valve body provided with a main water inlet, a communicating water inlet, and a mixed water outlet; A nozzle disposed in the valve body. The nozzle includes a first flow channel, a second flow channel, and a converging section flow channel arranged coaxially. The first flow channel is communicated with the main water inlet, the second flow channel is communicated with the communicating water inlet, the end of the converging section flow channel is communicated with the mixed water outlet, a circumferential annular limiting block is convexly provided on the inner wall of the second flow channel, and a spray hole is opened at the center of the annular limiting block; A needle that movably penetrates through the spray hole along the axis of the nozzle. The needle includes: A needle tip section, one end of which extends out of the first flow channel. An adjusting spring is sleeved on the needle tip section. One end of the adjusting spring is fixed to a spring seat located at the end of the needle tip section, and the other end is fixed to the nozzle; A needle tail section located in the second flow channel, which includes a positive taper section, and the diameter of the positive taper section gradually expands from the needle tip section to the needle tail section; When the fluid pressure at the main water inlet increases, the high-pressure fluid compresses the adjusting spring and pushes the needle towards the mixed water outlet direction. The gap between the positive taper section and the inner wall of the spray hole increases, accelerating the formation of negative pressure at the communicating water inlet and strengthening the negative pressure entrainment; When the fluid pressure at the main water inlet decreases, the adjusting spring rebounds and drives the needle towards the main water inlet direction. The gap between the positive taper section of the needle tail and the inner wall of the spray hole decreases, and the negative pressure entrainment weakens.

[0004] Preferably, the stiffness coefficient of the adjusting spring and the fluid rated pressure range at the main water inlet satisfy: k = (0.15 - 0.3)Pmax ×A / Δx, where k is the spring stiffness coefficient (N / mm), and P max is the maximum pump starting pressure at the main water inlet (MPa), Δx is the maximum stroke displacement of the needle (mm), and A is the pressure-bearing area of the needle head section (mm²).

[0005] Preferably, the pre-tightening force F of the adjusting spring 0 and the minimum and maximum pump starting pressures at the main water inlet satisfy: F 0 = 0.12P max ×A + 0.3P min ×A, where A is the pressure-bearing area of the needle head section (mm²), and P min is the minimum pump starting pressure, and P max is the maximum pump starting pressure.

[0006] Preferably, the spring seat is threadedly connected to the end of the needle head section, and the spring seat is provided with a pressure-bearing surface perpendicular to the axis of the needle, and the pressure-bearing surface constitutes the pressure-bearing area of the needle head section.

[0007] Preferably, the needle head section includes a needle body and a plurality of rib sections evenly distributed along the circumference of the needle body and extending in the axial direction thereof, and a fluid passage is formed between the plurality of rib sections.

[0008] Preferably, the rib section includes a first rib portion and a second rib portion. The first rib portion is opposite to the connection between the second flow channel and the communication water inlet, and its radial dimension is smaller than that of the second rib portion to form a fluid passage with the inner cavity wall of the second flow channel; A slot corresponding to the second rib portion is formed on the inner cavity wall of the nozzle, and the second rib portion is slidably arranged on the slot along the axial direction of the nozzle.

[0009] Preferably, the converging section flow channel includes a mixing section and a diffusing section arranged in sequence from its water inlet end to the water outlet end. The diffusing section has a conical expansion structure. The mixing section and the diffusing section are transitioned through a gradually shrinking connecting section. The radius of curvature R of the connecting section and the diameter D of the mixing section satisfy R = 0.3D to 0.6D, and the outlet diameter d of the diffusing section 2 and the inlet diameter d of the mixing section 1 The ratio d 2 / d 1 = 1.2 to 1.8.

[0010] Preferably, a reverse cone section is provided at the end of the needle tail section. The diameter of the reverse cone section gradually expands from the end close to the spray hole to the far end, and forms a gradually shrinking annular flow with the inner wall of the second flow channel. The ratio of the outlet cross-sectional area to the inlet cross-sectional area of the gradually shrinking annular flow channel is 1:1.5 to 2.5.

[0011] Preferably, the taper angle α of the reverse taper section is 10 to 25°, and the end of the reverse taper section extends to form a guiding boss. The minimum clearance between its outer diameter and the inner wall of the second flow channel is 0.5 to 1.2 mm, and the ratio of the length L to the inlet diameter d 3 of the tapered annular flow channel 3 is L / d = 0.8 to 1.2.

[0012] Preferably, the valve body is provided with an outlet water port at the upstream end of the first fluid; It further includes a branch pipe, and both ends thereof are respectively communicated with the outlet water port and the communicating water inlet.

[0013] The present invention has at least the following beneficial effects: First, by arranging an adjusting spring on the injection needle, the present invention can automatically adjust according to the fluid pressure of the main water inlet.

[0014] Second, by calculating and setting the stiffness coefficient and pre-tightening force of the adjusting spring, the present invention ensures the accurate movement of the injection needle, can maintain stable performance under different working conditions, effectively adapts to the change of the main water inlet pressure, and meets the diverse use requirements.

[0015] Third, through the transition of the mixing section and the diffusion section through a connecting section with a specific radius of curvature, and the setting of the ratio of the outlet diameter of the diffusion section to the inlet diameter of the mixing section, the present invention is conducive to the full mixing of the fluid, reduces the formation of vortices and turbulence at the connection, reduces the energy loss, and improves the energy utilization efficiency of the entire jet valve Other advantages, objectives and features of the present invention will be partially reflected by the following description, and partially will also be understood by those skilled in the art through the research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A side cross-sectional view of the automatic-adjusting jet dynamic circulation valve in a high-pressure state according to one technical solution of the present invention; Figure 2 A side cross-sectional view of the automatic-adjusting jet dynamic circulation valve in a low-pressure state according to one technical solution of the present invention; Figure 3 An exploded view of the injection needle according to one technical solution of the present invention; Figure 4 A side structural schematic diagram of the nozzle according to one technical solution of the present invention; Figure 5 A side structural schematic diagram of the injection needle assembly on the nozzle according to one technical solution of the present invention.

[0017] Among them, the marks in each drawing are as follows: 1. Valve body; 2. Main water inlet; 3. Connecting water inlet; 4. Mixed water outlet; 5. Expenditure water outlet; 6. Nozzle; 7. Spray needle; 8. Mixing section; 9. Diffusion section; 10. Adjusting spring; 11. Spring seat; 12. Forward conical section; 13. Reverse conical section; 14. Needle tail section; 15. First ribbed part; 16. Second ribbed part; 17. Ribbed section; 18. First flow channel; 19. Second flow channel; 20. Contracting section flow channel; 21. Spray hole. Detailed implementation manner

[0018] The following further describes the present invention in detail with reference to the accompanying drawings, so that those skilled in the art can implement it according to the description in the specification.

[0019] It should be noted that the experimental methods described in the following implementation schemes are all conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified; in the description of the present invention, the orientation or positional relationship indicated by the terms is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0020] As Figures 1 to 5 shown, the present invention provides an automatically adjustable jet dynamic circulation valve, including: A valve body 1, which is provided with a main water inlet 2, a connecting water inlet 3 and a mixed water outlet 4; specifically, the valve body 1 is the main structure of the automatically adjustable jet dynamic circulation valve, usually made of high-strength and corrosion-resistant metal materials (such as stainless steel) to ensure its reliability and durability in different working environments. The main water inlet 2 is used to connect to high-pressure fluid, the connecting water inlet 3 is used to connect to the fluid that needs to be entrained, and the mixed water outlet 4 outputs the mixed fluid. Nozzle 6 is provided within valve body 1. Nozzle 6 includes a first flow channel 18, a second flow channel 19, and a converging section flow channel 20 that are coaxially arranged. The first flow channel 18 communicates with the main water inlet 2, the second flow channel 19 communicates with the connecting water inlet 3, the end of the converging section flow channel 20 communicates with the mixing water outlet 4. The inner wall of the second flow channel 19 is circumferentially convex with an annular limiting block, and a spray hole 21 is provided at the center of the annular limiting block. Specifically, the function of the first flow channel 18 is to guide the high-pressure fluid from the main water inlet 2 into the nozzle 6. The inner diameter and length of the first flow channel 18 are designed according to the flow rate and pressure of the main water inlet 2 to ensure that the fluid can flow in smoothly. The second flow channel 19 is used to introduce the fluid to be entrained. The annular limiting block is provided at the connection between the second flow channel 19 and the converging section flow channel 20. The function of the annular limiting block is to limit the movement range of the spray needle 7 and provide support and guidance for the spray needle 7. The function of the converging section flow channel 20 is to mix the fluids flowing in from the first flow channel 18 and the second flow channel 19 and accelerate the flow of the fluid. The design of the converging section flow channel 20 can improve the mixing effect and entrainment efficiency of the fluid; Spray needle 7, which movably penetrates through the spray hole 21 along the axis direction of the nozzle 6. Spray needle 7 includes: Needle tip section, one end of which extends out of the first flow channel 18. An adjusting spring 10 is sleeved on the needle tip section. One end of the adjusting spring 10 is fixed on the spring seat 11 located at the end of the needle tip section, and the other end is fixed on the nozzle 6. Specifically, the spring seat 11 can be fixed at the end of the needle tip section by means of threaded connection, which is convenient for the installation and disassembly of the adjusting spring 10. The function of the adjusting spring 10 is to drive the spray needle 7 to move within the spray hole 21 according to the change of the fluid pressure at the main water inlet 2; Needle tail section 14, located within the second flow channel 19, which includes a positive taper section 12, and the diameter of the positive taper section 12 gradually expands from the needle tip section to the needle tail section 14. Specifically, the gap size between the positive taper section 12 and the inner wall of the spray hole 21 determines the intensity of negative pressure entrainment; When the fluid pressure at the main water inlet 2 increases, the high-pressure fluid compresses the adjusting spring 10 and pushes the spray needle 7 to move towards the mixing water outlet 4 direction. The gap between the positive taper section 12 and the inner wall of the spray hole 21 increases, causing the fluid flow rate within the second flow channel 19 to increase, thereby accelerating the formation of negative pressure at the connecting water inlet 3 and strengthening the negative pressure entrainment; When the fluid pressure at the main water inlet 2 decreases, the adjusting spring 10 rebounds and drives the spray needle 7 to move towards the main water inlet 2 direction. The gap between the positive taper section 12 of the needle tail and the inner wall of the spray hole 21 decreases, causing the fluid flow rate within the second flow channel 19 to decrease, thereby slowing down the formation of negative pressure at the connecting water inlet 3 and weakening the negative pressure entrainment.

[0021] In the above technical solution, after the main fluid inlet 2 is connected, when the fluid pressure at the main inlet 2 increases, the high-pressure fluid acts on the needle section. The acting force of the fluid compresses the adjusting spring 10. After the adjusting spring 10 is compressed, it pushes the injection needle 7 to move towards the mixing outlet 4. As the injection needle 7 moves, the gap between the positive conical section 12 and the inner wall of the injection hole 21 increases. According to the principle of fluid mechanics, after the gap increases, the flow rate of the fluid accelerates, thereby forming a stronger negative pressure at the connecting water inlet 3, which will accelerate the injection of the fluid at the connecting water inlet 3 into the nozzle 6, strengthening the negative pressure injection effect, so that more entrained fluid is mixed with the high-pressure fluid at the main inlet 2 in the converging section flow path 20, and then output from the mixing outlet 4; when the fluid pressure at the main inlet 2 decreases, the pressure acting on the needle section decreases, and the adjusting spring 10 rebounds under the acting force of the previous compression. The rebound of the adjusting spring 10 drives the injection needle 7 to move towards the main inlet 2. At this time, the gap between the positive conical section 12 at the needle tail and the inner wall of the injection hole 21 decreases. After the gap decreases, the flow rate of the fluid slows down, the negative pressure at the connecting water inlet 3 weakens, and the negative pressure injection effect also weakens accordingly, and the flow rate of the entrained fluid decreases correspondingly. The function of automatically adjusting the negative pressure injection intensity according to the fluid pressure at the main inlet 2 of the present invention enables the jet valve to adapt to different working pressure environments, without frequent manual intervention, greatly improving the work efficiency and reducing the labor cost.

[0022] In another technical solution, the stiffness coefficient of the adjusting spring 10 and the fluid rated pressure range of the main inlet 2 satisfy: k = (0.15~0.3)P max ×A / Δx, where k is the spring stiffness coefficient (N / mm), P max is the maximum pump starting pressure (MPa) of the main inlet 2, Δx is the maximum stroke displacement (mm) of the injection needle 7, and A is the pressure receiving area (mm²) of the needle section; specifically, in the actual application scenario of the jet valve, first, a pressure sensor can be used to measure the maximum pump starting pressure of the main inlet 2. During multiple normal operation cycles of the system, record the pressure values of the main inlet 2 each time the pump is started, and select the maximum value among them as P max , and make corrections according to the actual situation. According to the design structure of the jet valve, the theoretical calculation and actual test of the maximum stroke displacement Δx of the injection needle 7 are carried out through geometric relations and mechanical principles, and then the specific value of A is determined according to the actual production. According to the above values, the stiffness coefficient of the adjusting spring 10 is calculated. According to the calculated spring stiffness coefficient, a suitable adjusting spring 10 is selected, which can avoid the problem of inaccurate adjustment caused by the adjusting spring 10 being too soft or too hard, making the adjustment process of the jet valve more precise and improving the accuracy of the negative pressure injection intensity adjustment.

[0023] In another technical solution, the pre-tightening force F0 of the adjusting spring 10, the minimum pump starting pressure and the maximum pump starting pressure of the main water inlet 2 satisfy: F0 = 0.12P max ×A + 0.3P min ×A, where A is the pressure-bearing area (mm²) of the needle section, and P min is the minimum pump starting pressure, and P max is the maximum pump starting pressure; specifically, in the system where the jet valve is actually applied, a pressure sensor is installed at the main water inlet 2, and the system is started multiple times. Record the pressure value of the main water inlet 2 each time the pump is started. The maximum value among them is P max , and the minimum value is P min . Select the adjusting spring 10 according to the calculated pre-tightening force, which ensures that at the minimum pump starting pressure, the adjusting spring 10 can provide sufficient initial force to keep the injection needle 7 in a proper initial position, ensuring that the jet valve can start smoothly and avoiding the situation of abnormal operation due to too low pressure. The formula also takes into account the influence of the maximum pump starting pressure, so that the adjusting spring 10 can maintain stable performance under high pressure. When the pressure at the main water inlet 2 reaches the maximum pump starting pressure, the pre-tightening force and the pressure change work together to ensure that the injection needle 7 can move according to the design requirements and maintain the normal working state of the jet valve, preventing component damage or adjustment failure caused by too high pressure.

[0024] In another technical solution, the spring seat 11 is threadedly connected to the end of the needle section. The spring seat 11 is provided with a pressure-bearing surface perpendicular to the axis of the injection needle 7, and the pressure-bearing surface constitutes the pressure-bearing area of the needle section; specifically, one end of the adjusting spring 10 is fixed on the spring seat 11, and the fixing method can be welding or other reliable connection methods. Align the internal thread of the spring seat 11 with the external thread at the end of the needle section and screw it in. During the screwing-in process, ensure that the axes of the two coincide to avoid deviation. The spring seat 11 and the needle section are threadedly connected, which is convenient for disassembly, installation or replacement. The pressure-bearing surface constitutes the pressure-bearing area of the needle section, and its size is clear and easy to measure.

[0025] In another technical solution, the needle tip section includes the main body of the injection needle 7 and a plurality of rib sections 17 that are evenly distributed along the circumferential direction of the main body of the injection needle 7 and extend in its axial direction. A fluid channel is formed between the plurality of rib sections 17. Specifically, in actual processing, the rib sections 17 can be formed by machining methods such as cutting, or the ribs and the main body of the injection needle 7 can be integrally formed, made of corrosion-resistant materials. Insert the injection needle 7 with the rib sections 17 into the injection hole 21 along the axis direction of the nozzle 6 to ensure that the injection needle 7 can slide freely within the injection hole 21. During the insertion process, pay attention to the position of the rib sections 17 to avoid interference with the inner wall of the nozzle 6. The rib sections 17 help to improve the negative pressure injection effect at the communication water inlet 3. A more uniform and smooth fluid flow can enable the fluid at the main water inlet 2 to more effectively form a negative pressure when passing through the nozzle 6, and inject the fluid at the communication water inlet 3 more quickly and stably.

[0026] In another technical solution, the rib section 17 includes a first rib portion 15 and a second rib portion 16. The first rib portion 15 is opposite to the connection part of the second flow channel 19 and the communication water inlet 3, and its radial dimension is smaller than that of the second rib portion 16 to form a fluid channel with the inner cavity wall of the second flow channel 19. Specifically, the length of the first rib portion 15 depends on the axial dimension of the water inlet of the nozzle 6, generally being the length dimension of the inlet of the first flow channel 18 in the axial direction of the injection needle 7 plus the stroke of the injection needle 7. A slot corresponding to the second rib portion 16 is formed on the inner cavity wall of the nozzle 6. The second rib portion 16 is slidably arranged on the slot along the axial direction of the nozzle 6. Specifically, the slot formed on the inner cavity wall of the nozzle 6 corresponding to the second rib portion 16 provides precise guidance for the movement of the injection needle 7. The size of the fluid channel formed by the first rib portion 15 and the inner cavity wall of the second flow channel 19, and the matching size between the second rib portion 16 and the slot on the inner cavity wall of the nozzle 6 ensure that the fluid can pass smoothly and the injection needle 7 can slide flexibly. The setting of the fluid channel enables the two fluids to meet in a more appropriate manner, increasing the contact area and mixing time between the fluids, thereby improving the mixing uniformity and ensuring the quality of the mixed fluid output from the mixed water outlet 4.

[0027] In another technical solution, the converging section flow channel 20 includes a water mixing section 8 and a diffusing section 9 arranged in sequence from its water inlet end to its water outlet end. The diffusing section 9 has a tapered expansion structure. The water mixing section 8 and the diffusing section 9 are transitioned through a gradually shrinking connecting section. The radius of curvature R of the connecting section and the diameter D of the water mixing section 8 satisfy R = 0.3D to 0.6D, and the outlet diameter d of the diffusing section 9 2 and the inlet diameter d of the water mixing section 8 1 The ratio d 2 / d 1= 1.2~1.8; Specifically, the smooth transition of the tapered connecting section reduces the local resistance loss of the fluid during the flow process. When the fluid enters the diffuser section 9 from the mixing section 8, if there is no appropriate transition structure, vortices and turbulences will be formed at the connection, resulting in a large amount of energy loss. The design of the reasonable curvature radius of the connecting section and the diameter ratio of the diffuser section 9 to the mixing section 8 enables the fluid to smoothly change the flow direction and speed, reduces this energy loss, and improves the energy utilization efficiency of the entire jet valve.

[0028] In another technical solution, a reverse taper section 13 is provided at the end of the needle tail section 14. The diameter of the reverse taper section 13 tapers from the needle head section to the needle tail section 14, and forms a tapered annular flow with the inner wall of the second flow channel 19. The ratio of the outlet cross-sectional area to the inlet cross-sectional area of the tapered annular flow channel is 1:1.5~2.5; specifically, through processes such as numerical control turning or grinding, it is ensured that the diameter of the reverse taper section 13 tapers from the needle head section to the needle tail section 14, and its taper is strictly controlled. According to the principle of fluid mechanics, when the fluid flows in the tapered flow channel, the flow velocity will gradually increase. When the fluid at the main water inlet 2 pushes the injection needle 7 to move, the fluid in the second flow channel 19 accelerates in the tapered annular flow channel, thereby forming a stronger negative pressure at the communicating water inlet 3, which can more effectively eject the fluid at the communicating water inlet 3, improve the ejection efficiency of the jet valve, and enable more fluid to be introduced into the mixing process. By controlling the ratio of the outlet cross-sectional area to the inlet cross-sectional area of the tapered annular flow channel within the range of 1:1.5~2.5, the acceleration degree of the fluid in the flow channel and the magnitude of the negative pressure can be precisely adjusted.

[0029] In another technical solution, the cone angle α of the reverse taper section 13 is 10~25°, and a guiding boss is formed by extending the end of the reverse taper section 13. The minimum clearance between its outer diameter and the inner wall of the second flow channel 19 is 0.5~1.2 mm, and the ratio of the length L of the tapered annular flow channel to the inlet diameter d 3 is L / d 3 = 0.8~1.2; Specifically, when the fluid flows from the larger diameter end to the smaller diameter end, the cone angle determines the rate and direction of the increase in the fluid flow velocity. An appropriate cone angle can maximize the fluid flow velocity while ensuring the smooth flow of the fluid. The clearance of 0.5~1.2 mm can not only ensure that the fluid can smoothly pass through the tapered annular flow channel, but also prevent the negative pressure from leaking due to too large a clearance, affecting the ejection effect. The ratio of 0.8~1.2 enables the fluid to have sufficient time and space for full mixing in the flow channel.

[0030] In another technical solution, an outlet water port 5 is provided at the upstream end of the valve body 1 where the first fluid is located. It further includes a branch pipe, the two ends of which are respectively communicated with the outlet water port 5 and the communicated water inlet 3; specifically, the connection modes of the branch pipe with the main water inlet 2 and the communicated water inlet 3 can be threaded connection, flange connection, welded connection, etc. The branch pipe introduces part of the fluid from the main water inlet 2 into the communicated water inlet 3 through the outlet water port 5, increasing the fluid energy at the communicated water inlet 3. When the fluid from the main water inlet 2 forms a negative pressure to eject the fluid from the communicated water inlet 3 through the nozzle 6, the additional fluid conveyed by the branch pipe can enhance this ejection effect, enabling more fluid to be ejected into the jet valve and improving the ejection efficiency.

[0031] Although the embodiments of the present invention have been disclosed as above, it is not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily achieved. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to specific details and the illustrations shown and described herein.

Claims

1. Automatically adjust the jet dynamic circulation valve, characterized in that: include: A valve body, on which a main water inlet, a connecting water inlet and a mixing water outlet are provided; The nozzle is arranged in the valve body, and comprises a first flow channel, a second flow channel and a contraction section flow channel which are coaxially arranged, the first flow channel is connected with the main water inlet, the second flow channel is connected with the connecting water inlet, the end of the contraction section flow channel is connected with the mixing water outlet, an annular stopper is convexly provided on the inner wall of the second flow channel in the circumferential direction, and a spray hole is opened in the center of the annular stopper; The spray needle is movably inserted into the spray hole along the axial direction of the nozzle, and the spray needle includes: A needle section, one end of which extends out of the first flow channel, and an adjusting spring is sleeved on the needle section, one end of the adjusting spring is fixed to a spring seat located at the end of the needle section, and the other end is fixed to the nozzle; The needle tail section is located in the second flow channel and includes a forward cone section, the diameter of which gradually expands from the needle head section to the needle tail section; When the fluid pressure at the main water inlet increases, the high-pressure fluid compresses the regulating spring, pushing the spray needle toward the mixed water outlet, increasing the gap between the forward cone section and the inner wall of the spray hole, accelerating the formation of negative pressure at the connected water inlet, and strengthening the negative pressure injection; When the fluid pressure at the main water inlet decreases, the spring rebound is adjusted to drive the spray needle to move toward the main water inlet, the gap between the forward cone section of the needle tail and the inner wall of the spray hole is reduced, and the negative pressure injection is weakened.

2. The automatic regulating fluid dynamic circulation valve according to claim 1, characterized in that: The stiffness coefficient of the regulating spring and the rated pressure range of the fluid at the main water inlet meet: k = (0.15 ~ 0.3) P max ×A / Δx, where k is the spring stiffness coefficient (N / mm), P max is the maximum pump start pressure of the main water inlet (MPa), Δx is the maximum displacement of the spray needle (mm), and A is the pressure area of ​​the needle section (mm²).

3. The automatic regulating fluid dynamic circulation valve according to claim 2, characterized in that: The preload force F0 of the adjustment spring meets the minimum pump start pressure and the maximum pump start pressure of the main water inlet: F0=0.12 P max ×A+0.3P min ×A, where A is the pressure area of ​​the needle section (mm²), P min is the minimum pump starting pressure, P max The maximum pump starting pressure.

4. The automatic regulating fluid dynamic circulation valve according to claim 3, characterized in that: The spring seat is threadedly connected to the end of the needle section. A pressure-bearing surface perpendicular to the axis of the spray needle is provided on the spring seat, and the pressure-bearing surface constitutes the pressure-bearing area of ​​the needle section.

5. The automatic regulating fluid dynamic circulation valve according to claim 2, characterized in that: The needle section comprises a spray needle body, a plurality of convex rib sections evenly distributed along the circumference of the spray needle body and extending along the axial direction thereof, and the plurality of convex rib sections form fluid channels among each other.

6. The automatic regulating fluid dynamic circulation valve according to claim 5, characterized in that: The convex rib section includes a first convex rib portion and a second convex rib portion, wherein the first convex rib portion is opposite to the connection point between the second flow channel and the water inlet, and has a radial dimension smaller than a radial dimension of the second convex rib portion, so as to form a fluid channel with the inner cavity wall of the second flow channel; A groove corresponding to the second convex rib is formed on the inner cavity wall of the nozzle, and the second convex rib is slidably arranged on the groove along the axial direction of the nozzle.

7. The automatic regulating fluid dynamic circulation valve according to claim 1, characterized in that: The contraction section flow channel includes a mixing section and a diffusion section which are sequentially arranged from the water inlet end to the water outlet end. The diffusion section presents a conical expansion structure. The mixing section and the diffusion section are transitioned through a tapered connecting section. The curvature radius R of the connecting section and the diameter D of the mixing section satisfy R=0.3D~0.6D, and the ratio of the outlet diameter d2 of the diffusion section to the inlet diameter d1 of the mixing section is d2 / d1=1.2~1.

8.

8. The automatic regulating fluid dynamic circulation valve according to claim 1, characterized in that: A reverse cone section is provided at the end of the needle tail section. The diameter of the reverse cone section gradually decreases from the needle head section to the needle tail section, and forms a tapered annular flow with the inner wall of the second flow channel. The ratio of the outlet cross-sectional area to the inlet cross-sectional area of ​​the tapered annular flow channel is 1:1.5~2.

5.

9. The automatic regulating fluid dynamic circulation valve according to claim 8, characterized in that: The cone angle α of the reverse cone section is 10~25°, and the end of the reverse cone section extends to form a guide boss, the minimum gap between its outer diameter and the inner wall of the second flow channel is 0.5~1.2 mm, and the ratio of the length L of the tapered annular flow channel to the inlet diameter d3 is L / d3=0.8~1.

2.

10. The automatic regulating fluid dynamic circulation valve according to claim 1, characterized in that: The valve body is provided with a water outlet at the upstream end of the first fluid; It also includes a branch pipe, both ends of which are respectively connected to the water outlet and the connecting water inlet.

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