Noise reduction structure of steam seal air ejector with tapered nozzle

Abstract

This utility model relates to a noise reduction structure for a steam seal ejector using a tapered nozzle, comprising a fixed pipe seat, an ejector chamber, a tapered nozzle, a mounting plate, a diffuser, and a housing. The tapered nozzle is mounted on the fixed pipe seat and arranged within the ejector chamber. The internal working steam flow channel of the tapered nozzle gradually narrows from the inlet to the outlet, with a certain thickness at the outlet end and no expansion section, forming a single-taper nozzle structure. By employing a tapered nozzle structure, the working steam, after passing through the nozzle, forms a subsonic to supersonic steam flow at the outlet. Compared to using a tapered Laval nozzle, the outlet steam velocity can be reduced by more than half. The steam seal ejector has sufficient suction capacity, and the significantly reduced steam velocity results in a substantial decrease in noise. It also reduces erosion of the ejector components, improving the reliability of the equipment.

Description

Technical Field

[0001] This utility model relates to the field of steam seal ejector technology, specifically to a noise reduction structure for a steam seal ejector using a tapered nozzle. It is suitable for maintaining a weak vacuum in the steam seal ejection system of a ship's secondary circuit and steam turbine system, and for removing steam leakage from the main steam valve, valve stem, front and rear steam seals, etc. Background Technology

[0002] Steam seal ejectors are used to maintain a weak vacuum in the steam turbine's steam seal extraction system, removing steam leaks from the main steam valves, valve stems, and front and rear steam seals to prevent steam from leaking into the compartments and the outside atmosphere. Conventional steam seal ejectors employ a scaling Laval nozzle structure, see [link to documentation]. Figure 2 The cross-section of the working steam flow channel gradually contracts after passing through the throat with the smallest cross-section, and then gradually expands again, forming a supersonic steam flow and the required vacuum at the nozzle outlet. The steam flow outlet velocity is very high, generally reaching more than twice the speed of sound, while generating huge noise. The noise source of the steam seal ejector mainly comes from the supersonic steam flow formed by the working steam passing through the expansion and contraction Laval nozzle outlet.

[0003] In existing technologies, such as the adjustable steam ejector nozzle disclosed in patent document CN115114795A, although the ejection efficiency has been improved by optimizing the nozzle profile and adjusting the cone structure, it still adopts a scaling nozzle design and has not solved the noise problem caused by supersonic airflow. Therefore, there is an urgent need for a steam seal ejector structure that can maintain the pumping capacity while effectively reducing noise. Summary of the Invention

[0004] This invention proposes a noise reduction structure for a steam seal ejector with a tapered nozzle, while maintaining the same nozzle mounting interface and external shape. The internal working steam flow channel gradually narrows from the inlet, and the outlet tail end is designed with a certain thickness without an expansion section. The overall nozzle shape is a tapered single-contraction nozzle structure.

[0005] To achieve the above objectives, the technical solution of this utility model is: a noise reduction structure for a steam seal ejector with a tapered nozzle, comprising a fixed pipe seat, an ejector chamber, a tapered nozzle, a mounting plate, a diffuser, and a housing; the tapered nozzle is installed on the fixed pipe seat and arranged in the ejector chamber, the internal working steam flow channel of the tapered nozzle gradually narrows from the steam inlet to the outlet, and the outlet tail end has a certain thickness and no expansion section, forming a single-taper nozzle structure.

[0006] Furthermore, the diffuser and the tapered nozzle are concentrically mounted on the mounting plate on the top of the housing.

[0007] Furthermore, the flow channel contraction angle of the tapered nozzle is 10°-30°.

[0008] Furthermore, the thickness of the exit tail end of the tapered nozzle is 0.5mm-2mm.

[0009] Furthermore, the diffuser has a gradually expanding structure, and its inlet diameter matches the outlet diameter of the gradually converging nozzle.

[0010] Furthermore, the expansion angle of the diffuser is 5°-15°.

[0011] The beneficial effects of this utility model are:

[0012] The cross-section of the working steam flow channel inside the nozzle gradually contracts and decreases along the steam flow direction. A certain thickness is designed at the outlet tail end, with no expansion section; the entire nozzle shape is a tapered single-contraction nozzle. By adopting a tapered nozzle structure, the working steam, after passing through the nozzle, forms a subsonic to sonic steam flow at the outlet. Compared to using a tapered Laval nozzle, the outlet steam velocity can be reduced by more than half. The suction capacity of the steam seal ejector is sufficient, and the noise is significantly reduced after the steam velocity is greatly reduced. It also reduces the erosion of the ejector components, improving the reliability of the equipment. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the noise reduction structure of the steam seal ejector with a tapered nozzle according to this utility model.

[0014] Figure 2 This is a schematic diagram of a scaled-down Laval nozzle structure in the prior art;

[0015] Figure 3 This is a schematic diagram of the tapered nozzle of this utility model;

[0016] In the diagram: 1. Fixed tube seat, 2. Ejector chamber, 3. Converging nozzle, 4. Mounting plate, 5. Diffuser, 6. Housing. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0018] like Figure 1 As shown in the figure, the present invention provides a noise reduction structure for a steam seal ejector with a tapered nozzle, mainly comprising six parts: a fixed tube seat 1, an ejector chamber 2, a nozzle 3, a mounting plate 4, a diffuser 5, and a housing 6. The nozzle 3 is mounted on the fixed tube seat 1 and arranged within the ejector chamber 2. The diffuser 5 is concentrically mounted on the top mounting plate 4 of the housing 6. The mounting interface and external shape of the nozzle 3 remain unchanged, such as... Figure 3 As shown, the internal working steam flow channel gradually narrows from the steam inlet, and the outlet end has a certain thickness. There is no expansion section, and the entire nozzle shape is a tapered single-contraction nozzle structure. The diffuser 5 can reduce the speed and increase the pressure of the steam flow, allowing the working steam after work and the intake steam-air mixture to be discharged from the casing together.

[0019] The steam seal ejector uses a tapered nozzle structure, see Figure 3 The cross-section of the working steam flow channel gradually contracts and decreases along the steam flow direction, forming a subsonic steam flow with a maximum speed of sound at the outlet. This maintains the required vacuum level, ensuring sufficient suction capacity for the steam seal ejector. The significant decrease in steam velocity results in a marked reduction in noise, achieving the noise reduction objective of the steam seal ejector.

[0020] Preferably, the nozzle's flow channel contraction angle is 10°-30°. This ensures that the steam is uniformly accelerated within the nozzle, forming a stable subsonic flow field at the outlet, which guarantees the vacuum required for pumping while effectively reducing airflow noise.

[0021] Preferably, the thickness of the nozzle outlet end is 0.5mm-2mm. This thickness range ensures the structural strength of the nozzle outlet while avoiding excessive thickness that could affect steam outflow efficiency and maintain the suction capacity of the ejector.

[0022] Preferably, the diffuser has a gradually expanding structure, with its inlet diameter matching the outlet diameter of the tapered nozzle. This achieves steam flow reduction and pressurization, effectively discharging the working steam after work and the intake steam-air mixture, maintaining system pressure balance, and improving extraction efficiency.

[0023] Preferably, the expansion angle of the diffuser is 5°-15°. This allows the vapor flow to slow down smoothly within the diffuser, reducing energy loss, avoiding additional noise, and ensuring the smooth discharge of the mixture.

Claims

1. A noise reduction structure for a gland steam ejector with a converging-diverging nozzle, characterized by: The fixed tube seat, the ejector chamber, the tapered nozzle, the mounting seat plate, the diffuser and the shell are included; the tapered nozzle is mounted on the fixed tube seat and arranged in the ejector chamber, the internal working steam flow channel of the tapered nozzle is gradually contracted from the steam inlet to the outlet, the tail end of the outlet is provided with a certain thickness and is not provided with an expansion section, and a single contraction nozzle structure is formed.

2. The noise reduction structure of a gland steam ejector with a tapered nozzle according to claim 1, characterized in that: The diffuser is concentrically mounted on the mounting seat plate at the top of the shell with the tapered nozzle.

3. The noise reduction structure of a gland steam ejector with a tapered nozzle according to claim 1, characterized in that: The contraction angle of the flow channel of the tapered nozzle is 10-30°.

4. The noise reduction structure of a gland steam ejector with a converging nozzle according to claim 1, characterized in that: The thickness of the tail end of the outlet of the tapered nozzle is 0.5-2 mm.

5. The noise reduction structure of a gland steam ejector with a converging nozzle according to claim 1, characterized in that: The diffuser is a gradually expanding structure, and the inlet diameter of the diffuser matches the outlet diameter of the tapered nozzle.

6. The noise reduction structure of a gland steam ejector with a converging nozzle according to claim 5, characterized in that: The expansion angle of the diffuser is 5-15°.

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