Large nozzle of double-jet needle direct-current inner control type impulse water turbine

Abstract

The present application belongs to the nozzle technical field, especially relates to a double spray needle straight flow internal control type impulse water turbine large nozzle.The technical scheme is as follows: a double spray needle straight flow internal control type impulse water turbine large nozzle, which comprises a nozzle pipe, one end of the nozzle pipe is connected with a nozzle cover, the nozzle cover is provided with a nozzle opening, and a main spray needle for opening or closing the nozzle opening is arranged in the nozzle pipe; the main spray needle is hollow and provided with an inner nozzle at the end, and a small spray needle for opening or closing the inner nozzle is arranged in the main spray needle.The double spray needle straight flow internal control type impulse water turbine large nozzle can effectively improve the stress condition of the main spray needle during opening and closing, and improve the small flow regulation and the nozzle cavitation condition.

Description

Technical Field

[0001] This invention belongs to the field of nozzle technology, and specifically relates to a large nozzle for a double-needle DC internal control type impact turbine. Background Technology

[0002] Currently, most domestic and international companies using high-head impact turbine nozzles employ a hydraulic internal control structure. Most nozzle assemblies incorporate springs (coil springs or disc springs) to assist in opening and closing, and to buffer the significant impact force generated during the opening and closing of the nozzle needle. However, with the continuous increase in unit capacity and nozzle jet diameter, the safety and structural integrity of the nozzle assembly are significantly limited and constrained, primarily in the following aspects:

[0003] First, as the unit capacity increases, the size of the internal springs also increases, making it difficult to customize the springs and guarantee their performance.

[0004] Secondly, the need to set a preload for the spring makes nozzle installation and maintenance difficult.

[0005] Third, the service life of the spring is closely related to the operating mode of the unit. When the unit operates at a small or large opening for a long time, the spring will be under long-term stress and fail, or even break. This will cause damage to the nozzle assembly servo cylinder and servo rod, resulting in significant economic losses to the power station.

[0006] Fourth, it is difficult to predict spring failure or breakage, and if an accident occurs, the power station will take a long time to recover.

[0007] Fifth, large nozzles operating at a small opening for extended periods will exacerbate cavitation and wear on the nozzle needle and nozzle orifice. Summary of the Invention

[0008] In order to solve the above-mentioned problems in the prior art, the purpose of this invention is to provide a large nozzle for a double-needle DC internal control type impact turbine that can effectively improve the stress condition during the opening and closing process of the main nozzle and the cavitation condition when closed.

[0009] The technical solution adopted in this invention is as follows:

[0010] A large nozzle for a dual-needle DC internal control type impact turbine includes a nozzle tube, one end of which is connected to a nozzle cover. The nozzle cover has a nozzle orifice. A main nozzle is installed inside the nozzle tube for opening or closing the nozzle orifice. The main nozzle is hollow inside and has an inner nozzle at its end. A small nozzle is installed inside the main nozzle for opening or closing the inner nozzle.

[0011] This invention features a small nozzle needle to facilitate operation at a small nozzle opening. At low flow rates, the main nozzle needle is closed while the small nozzle needle is open, reducing cavitation between the main nozzle needle and the main nozzle. This allows the unit to operate at low flow rates for extended periods.

[0012] When the unit starts up, the main nozzle is in the closed position, and the small nozzle is opened at this time; when an increase in flow is required, the main nozzle is opened. When the unit shuts down, the main nozzle closes first, and the small nozzle closes only after the main nozzle has completely closed. This effectively improves the stress on the main nozzle, making its operation more flexible and reliable; it also extends the unit shutdown time and reduces the pressure rise of the unit.

[0013] As a preferred embodiment of the present invention, the main spray needle is connected to a main spray needle relay.

[0014] As a preferred embodiment of the present invention, the main nozzle relay is provided with a guide tube, the main nozzle is fitted with a hydraulic balance sleeve, the hydraulic balance sleeve contacts the lower edge of the cover plate, the main nozzle is also provided with an extension tube, the extension tube is fitted inside the guide tube, and the annular surface between the extension tube, the guide tube, the hydraulic balance sleeve and the sealing plate of the main nozzle forms a hydraulic balance cavity.

[0015] As a preferred embodiment of the present invention, the small spray needle is connected to a small spray needle relay.

[0016] In a preferred embodiment of the present invention, the cone angle of the nozzle cover is the same as the cone angle of the main nozzle. The cone angles of the nozzle cover and the main nozzle can vary depending on the actual situation, but having the same cone angle is a preferred embodiment. When the nozzle opening is open, water flows along the gap between the nozzle cover and the main nozzle. When the cone angle of the nozzle cover matches the cone angle of the main nozzle, the water can be sprayed out in a defined direction.

[0017] As a preferred embodiment of the present invention, the cone angle of the outer end of the small nozzle is the same as the cone angle of the main nozzle. The cone angle of the outer end of the small nozzle and the cone angle of the main nozzle can vary depending on the actual situation, but having the same cone angle is a preferred embodiment. Because the cone angle of the outer end of the small nozzle matches the cone angle of the main nozzle, when the small nozzle closes the inner nozzle, the water flow can smoothly pass through the junction of the main nozzle and the small nozzle, avoiding turbulence caused by the difference in their cone angles.

[0018] In a preferred embodiment of the present invention, the inner nozzle of the main nozzle is shaped as a cylindrical cavity, and the small nozzle is provided with a cylindrical surface that mates with the cylindrical cavity of the inner nozzle. The small nozzle contacts the inner nozzle through the cylindrical surface, and the contact distance between the small nozzle and the inner nozzle of the main nozzle is long enough to ensure more reliable closing of the small nozzle.

[0019] In a preferred embodiment of the present invention, a conical transition surface is provided between the inner nozzle of the main nozzle and the hollow cavity of the main nozzle, and the conical angle of the conical transition surface is the same as the conical angle of the outer end of the small nozzle. The conical angle of the conical transition surface and the conical angle of the outer end of the small nozzle may vary depending on the actual situation; however, it is a preferred embodiment that the conical angle of the conical transition surface is the same as the conical angle of the outer end of the small nozzle. When the inner nozzle is open, the internal water flows through the gap between the small nozzle and the conical transition surface. When the conical angle of the conical transition surface matches the conical angle of the outer end of the small nozzle, the internal water can be ejected at a defined angle.

[0020] A control method for a large nozzle of a dual-needle DC internally controlled impulse turbine includes the following steps:

[0021] When the unit starts up, the main nozzle is in the closed position, and the small nozzle is opened at this time. When an increase in flow is required, the main nozzle is opened.

[0022] When the unit is shut down, the main nozzle closes first, and the small nozzle closes only after the main nozzle has closed completely.

[0023] When the main nozzle is closed, the small nozzle is open.

[0024] The beneficial effects of this invention are as follows:

[0025] 1. This invention features a small nozzle needle to facilitate operation at a small nozzle opening. At low flow rates, the main nozzle needle is closed while the small nozzle needle is open, reducing cavitation between the main nozzle needle and the main nozzle. The unit can operate at low flow rates for extended periods.

[0026] 2. When the unit starts up, the main nozzle is in the closed position, and the small nozzle is opened at this time; when an increase in flow is required, the main nozzle is opened. When the unit shuts down, the main nozzle closes first, and the small nozzle closes only after the main nozzle has completely closed. This can effectively improve the stress on the main nozzle, making its operation more flexible and reliable; at the same time, it can extend the unit shutdown time and reduce the rise in unit pressure.

[0027] 3. The main nozzle adopts a DC internal control structure and a hydraulic self-balancing method, effectively reducing operating oil pressure. The nozzle can remain at any position, achieving the purpose of flow regulation. The opening and closing of the nozzle uses a combination of water pressure and oil pressure, making operation flexible and reliable. Attached Figure Description

[0028] Figure 1 This is a diagram showing the main nozzle and small nozzle in the fully closed state;

[0029] Figure 2 This is a schematic diagram showing the main nozzle fully closed and the small nozzle open with a small flow rate.

[0030] Figure 3 This is a diagram showing the small nozzle and the main nozzle partially open.

[0031] Figure 4 This is a diagram showing the main nozzle fully open and the small nozzles open.

[0032] Figure 5 This is a diagram showing the small nozzle closed and the main nozzle fully open.

[0033] Figure 6 This is a diagram showing the main nozzle fully closed and the small nozzles partially open.

[0034] In the diagram: 1-Nozzle tube; 2-Main nozzle; 3-Small nozzle; 4-Guide tube; 5-Hydraulic balance sleeve; 11-Nozzle cover; 12-Nozzle opening; 21-Inner nozzle; 22-Extension tube. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the invention can be combined with each other.

[0037] like Figures 1-6 As shown, the dual-needle DC internal control type impact turbine large nozzle of this embodiment includes a nozzle tube 1, one end of which is connected to a nozzle cover 11, the nozzle cover 11 is provided with a nozzle port 12, and a main nozzle 2 for opening or closing the nozzle port 12 is provided inside the nozzle tube 1; the main nozzle 2 is hollow inside and an inner nozzle 21 is provided at its end, and a small nozzle 3 for opening or closing the inner nozzle 21 is provided inside the main nozzle 2.

[0038] The present invention incorporates a small nozzle 3 to facilitate operation with a small nozzle opening. At low flow rates, the main nozzle 2 is closed, while the small nozzle 3 is open, reducing cavitation between the main nozzle 2 and the main nozzle. This allows the unit to operate at low flow rates for extended periods.

[0039] When the unit starts up, the main nozzle 2 is in the closed position, and the small nozzle 3 is opened at this time; when an increase in flow is required, the main nozzle 2 is opened. When the unit shuts down, the main nozzle 2 closes first, and the small nozzle 3 is closed after the main nozzle 2 has completely closed. This can effectively improve the stress on the main nozzle 2, making the operation of the main nozzle 2 more flexible and reliable; at the same time, it can extend the unit shutdown time and reduce the rise in unit pressure.

[0040] Furthermore, the main nozzle 2 is connected to a main nozzle relay. The small nozzle 3 is connected to a small nozzle relay. A guide tube 4 is provided on the main nozzle relay, and a hydraulic balance sleeve 5 is fitted on the main nozzle 2. The hydraulic balance sleeve 5 contacts the lower edge of the cover plate. An extension tube 22 is also provided on the main nozzle 2. The extension tube 22 is fitted inside the guide tube 4. The annular surface between the extension tube 22, the guide tube 4, the hydraulic balance sleeve 5, and the upper sealing plate of the main nozzle 2 forms a hydraulic balance cavity.

[0041] The main nozzle 2 adopts a DC internal control structure and uses a hydraulic self-balancing method to effectively reduce operating oil pressure. The nozzle can stay at any position to achieve flow regulation. The opening and closing of the nozzle is achieved by a combination of water pressure and oil pressure, making operation flexible and reliable. A coaxial small nozzle 3 is set inside the main nozzle 2, and the small nozzle 3 and the main nozzle 2 are controlled by oil pressure independently.

[0042] Furthermore, the cone angle of the nozzle cover 11 is the same as the cone angle of the main nozzle 2. The cone angles of the nozzle cover 11 and the main nozzle 2 can vary depending on the actual situation; however, it is a preferred embodiment that the cone angles of the nozzle cover 11 and the main nozzle 2 are the same. When the nozzle opening 12 is open, the water flows along the gap between the nozzle cover 11 and the main nozzle 2. When the cone angle of the nozzle cover 11 matches the cone angle of the main nozzle 2, the water can be sprayed out in a defined direction.

[0043] The cone angle at the outer end of the small nozzle 3 is the same as the cone angle of the main nozzle 2. The cone angles of the small nozzle 3 and the main nozzle 2 can vary depending on the actual situation; however, it is preferred that the cone angles of the small nozzle 3 and the main nozzle 2 are the same. Because the cone angles of the small nozzle 3 and the main nozzle 2 match, when the small nozzle 3 closes the inner nozzle 21, the water flow can smoothly pass through the junction of the main nozzle 2 and the small nozzle 3, avoiding turbulence caused by the difference in their cone angles.

[0044] The inner nozzle 21 of the main nozzle 2 is shaped as a cylindrical cavity, and the small nozzle 3 is provided with a cylindrical surface that mates with the cylindrical cavity of the inner nozzle 21. The small nozzle 3 contacts the inner nozzle 21 through the cylindrical surface, and the contact distance between the small nozzle 3 and the inner nozzle 21 of the main nozzle 2 is long enough to ensure more reliable closing of the small nozzle 3.

[0045] A conical transition surface is provided between the inner nozzle 21 of the main nozzle 2 and the hollow cavity of the main nozzle 2. The cone angle of the conical transition surface is the same as the cone angle of the outer end of the small nozzle 3. The cone angle of the conical transition surface and the cone angle of the outer end of the small nozzle 3 can vary according to the actual situation. It is a preferred solution that the cone angle of the conical transition surface is the same as the cone angle of the outer end of the small nozzle 3. When the inner nozzle 21 is open, the water inside flows through the gap between the small nozzle 3 and the conical transition surface. When the cone angle of the conical transition surface matches the cone angle of the outer end of the small nozzle 3, the water inside can be sprayed out at a certain angle.

[0046] The nozzle of this invention features a bidirectional seal at a critical sealing point, with a leakage pipeline installed between the seals to effectively monitor the reliability of the seal.

[0047] The control method for the large nozzle of the dual-needle DC internal control type impulse turbine in this embodiment includes the following methods:

[0048] like Figure 1 As shown, before the unit is started, both the main nozzle 2 and the small nozzle 3 are fully closed, and the water in the pressure pipeline is still. Figure 2 As shown, when the small nozzle 3 of the unit is open, the unit can start and run at a low flow rate. When the main nozzle 2 is in the fully closed position, the built-in relay drives the small nozzle 3 to move towards the water inlet direction. The small nozzle 3 and the main nozzle 2 form an opening, and the water in the pressure pipeline flows from the water inlet direction to the water outlet direction through the opening.

[0049] like Figure 3 As shown, all small nozzles 3 are in the open state. To increase the flow rate, the main nozzle 2 opens slowly, remaining in a partially open state. Figure 4 As shown, with the main nozzle 2 fully open and the unit operating at high flow rates, the small nozzle 3 can be slowly closed until... Figure 5 Illustration. The main nozzle 2 is balanced by the force and hydraulics of the relay (achieved through the hydraulic balance sleeve 5). The main nozzle 2 can stay at any position, which can accurately adjust the water inlet flow rate, achieve flow passage and control the water flow rate entering the turbine channel.

[0050] like Figure 5 As shown, with the main nozzle 2 fully open, the unit operates at a high flow rate, while the small nozzle 3 is closed. Both the main nozzle 2 and the small nozzle 3 can move synchronously, serving as a flow rate regulator. When the small nozzle 3 is fully closed, the main nozzle 2's operating lever and built-in relay drive the main nozzle 2 towards the water inlet direction until the main nozzle 2 or the built-in relay contacts the nozzle pipe 1. At this point, the main nozzle 2 is fully open, and water in the pressure pipeline flows from the main nozzle 2 to the nozzle outlet 12 ring on the nozzle cover 11, forming an opening. With the main nozzle 2 fully open, the unit operates at a high flow rate. (The last sentence appears to be a separate, unrelated statement.) Figure 6As shown, when shutting down, first close the main nozzle 2. When the small nozzle 3 is opened, it can effectively balance part of the force on the main nozzle 2. The main nozzle 2 closes slowly. After the main nozzle 2 is fully closed, the small nozzle 3 is closed.

[0051] This nozzle can be used in large or giant impulse turbines with ultra-high heads of 100m and above. The nozzle adopts a DC internal control structure, ensuring good flow characteristics. The nozzle needle uses a hydraulic balance system, allowing it to remain in any position for precise flow control. The nozzle needle has a full-range self-closing tendency; in the event of hydraulic system failure, it will slowly close itself to ensure power station safety. The nozzle needle can be disassembled from the front or rear. The internal spring structure has been eliminated, effectively protecting the nozzle body and enabling quick and convenient power station maintenance.

[0052] This invention is not limited to the above-described optional embodiments. Anyone can derive other various forms of products under the guidance of this invention. However, regardless of any changes made in their shape or structure, any technical solution that falls within the scope of the claims of this invention shall be protected by this invention.

Claims

1. A large nozzle for a dual-needle DC internally controlled impact turbine, characterized in that: It includes a nozzle tube (1), one end of which is connected to a nozzle cover (11), the nozzle cover (11) is provided with a nozzle port (12), and a main nozzle (2) for opening or closing the nozzle port (12) is provided inside the nozzle tube (1); the main nozzle (2) is hollow inside and an inner nozzle (21) is provided at its end, and a small nozzle (3) for opening or closing the inner nozzle (21) is provided inside the main nozzle (2); When the unit starts, the main nozzle (2) is in the closed position, and the small nozzle (3) is opened. When the flow rate needs to be increased, the main nozzle (2) is opened. When the unit is shut down, the main nozzle (2) is closed first, and the small nozzle (3) is closed after the main nozzle (2) is closed. When the main nozzle (2) is in the closed state, the small nozzle (3) is opened. The main nozzle (2) is connected to a main nozzle relay; The main nozzle relay is provided with a guide tube (4), and a hydraulic balance sleeve (5) is fitted on the main nozzle (2). The hydraulic balance sleeve (5) contacts the lower edge of the cover plate. An extension tube (22) is also provided on the main nozzle (2). The extension tube (22) is fitted inside the guide tube (4). The annular surface between the extension tube (22), the guide tube (4), the hydraulic balance sleeve (5), and the sealing plate on the main nozzle (2) forms a hydraulic balance cavity.

2. The large nozzle for a dual-needle DC internal control impact turbine according to claim 1, characterized in that: The small nozzle (3) is connected to a small nozzle relay.

3. The large nozzle for a dual-needle DC internal control impact turbine according to claim 1, characterized in that: The cone angle of the nozzle cap (11) is the same as that of the main nozzle (2).

4. The large nozzle for a dual-needle DC internal control impact turbine according to claim 1, characterized in that: The cone angle at the outer end of the small nozzle (3) is the same as the cone angle of the main nozzle (2).

5. A large nozzle for a dual-needle DC internal control impact turbine according to claim 1, characterized in that: The inner nozzle (21) of the main nozzle (2) is shaped as a cylindrical cavity, and the small nozzle (3) is provided with a cylindrical surface that cooperates with the cylindrical cavity of the inner nozzle (21).

6. A large nozzle for a dual-needle DC internal control impact turbine according to claim 1, characterized in that: A conical transition surface is provided between the inner nozzle (21) of the main nozzle (2) and the hollow cavity of the main nozzle (2), and the conical angle of the conical transition surface is the same as the conical angle of the outer end of the small nozzle (3).

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