A high-vacuum three-stage vacuum generator

Abstract

This utility model discloses a high-vacuum three-stage vacuum generator, relating to the technical field of rail train components. The high-vacuum three-stage vacuum generator includes a nozzle, a connecting pipe, a first-stage expander, a second-stage expander, and a third-stage expander connected in series along the airflow direction. The first-stage, second-stage, and third-stage expander are all hollow tubes, each internally equipped with a gradually contracting flow channel, a gradually expanding flow channel, and a gradually expanding flow channel, respectively. The inlet of each flow channel is connected to the external environment of the vacuum generator through vents formed on the corresponding tube wall, and one-way valves are installed at the vents of the second-stage and third-stage expander. This utility model, through its three-stage differentiated flow channels, multi-gap entrainment combined with a vent inlet structure, solves the problem of low acceleration and entrainment efficiency in traditional single-stage / two-stage flow channels under high-altitude, low-pressure environments. It can efficiently convert compressed air into a high-speed jet and form a stable negative pressure, improving the vacuuming speed in high-altitude areas and saving energy.

Description

Technical Field

[0001] This utility model relates to the field of rail train accessories technology, specifically to a high-vacuum three-stage vacuum generator. Background Technology

[0002] In the field of rail transit, the stable operation of the vacuum toilet system of EMU trains depends on the efficient vacuum pumping capability of the vacuum generator. The vacuum generator is the core execution unit of the vacuum generator, and its performance directly determines the adaptability of the system in different altitude environments.

[0003] Currently, mainstream vacuum generators in the industry are mainly designed for low-altitude areas with an altitude of ≤1500 meters, without considering the special environmental characteristics of high-altitude areas, such as thin air and low air pressure; for example, the Sichuan-Tibet Railway currently has an average altitude of 3800 meters and a maximum altitude of 5100 meters. Traditional vacuum generators have the following key drawbacks when used in high-altitude areas: Traditional vacuum generators typically use a conventional flow channel that "contracts first and then expands." Single-stage or two-stage structures can only achieve basic airflow acceleration and entrainment, which can barely meet vacuum requirements in low-altitude environments. However, in high-altitude and low-pressure environments, the airflow density is low and the kinetic energy transfer efficiency decreases. The acceleration capability of traditional flow channels is insufficient, resulting in a significant reduction in the efficiency of entrainment vacuum.

[0004] In summary, how to solve the problem that the conventional single / two-stage flow channel of the traditional vacuum generator, which "contracts first and then expands", suffers from insufficient acceleration and a significant reduction in vacuum efficiency due to low airflow density and decreased kinetic energy transfer efficiency in high-altitude and low-pressure environments is a technical problem that urgently needs to be solved by those skilled in the art.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of this utility model and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Utility Model Content

[0006] To address the aforementioned technical problems, this utility model provides a high-vacuum three-stage vacuum generator to solve the problems mentioned in the background section.

[0007] This utility model provides the following technical solution: a high-vacuum three-stage vacuum generator, comprising a nozzle, a connecting pipe, a first-stage expansion pipe, a second-stage expansion pipe and a third-stage expansion pipe connected in series along the airflow direction; The primary, secondary, and tertiary expansion tubes are all hollow tubes, and each has a primary flow channel, a secondary flow channel, and a tertiary flow channel respectively arranged along the tube axis. The cross-section of the primary flow channel has a gradually contracting structure from its inlet end to its outlet end; The cross-section of the secondary flow channel has a gradually expanding structure from its inlet end to its outlet end; The cross-section of the three-stage flow channel has a gradually expanding structure from its inlet end to its outlet end. The inlets of the primary, secondary, and tertiary flow channels are all connected to the external environment of the vacuum generator through vents opened on the corresponding pipe walls, and one-way valves are installed at the vents of the secondary and tertiary expansion tubes.

[0008] Preferably, the nozzle has an integrated flow channel running through it along the airflow direction. The integrated flow channel includes a compressed air inlet section and a nozzle section connected in sequence. The nozzle section includes a contraction section and an expansion section connected in sequence along the airflow direction.

[0009] Preferably, the flow channel cross-section of the contraction section gradually contracts from the compressed air inlet section to the expansion section; the flow channel cross-section of the expansion section gradually expands from the tail of the compressed air inlet section to the tail of the expansion section.

[0010] Preferably, a nozzle and a primary expansion tube are fixedly connected to both sides of the connecting pipe, respectively; there is a first gap between the air outlet end of the nozzle and the air inlet end of the primary flow channel, and a first air hole is provided on the pipe wall of the connecting pipe.

[0011] Preferably, a connecting pipe and a secondary expansion pipe are fixedly connected to both sides of the primary expansion pipe respectively; there is a second gap between the air outlet end of the primary flow channel and the air inlet end of the secondary flow channel; a second air hole is provided on the pipe wall of the primary expansion pipe, and a first one-way valve is provided on the second air hole.

[0012] Preferably, a primary expansion tube and a tertiary expansion tube are fixedly connected to both sides of the secondary expansion tube respectively; there is a third gap between the air outlet of the secondary flow channel and the air inlet of the tertiary flow channel; a third air hole is provided on the tube wall of the secondary expansion tube; and a second one-way valve is provided on the third air hole.

[0013] Preferably, the check valve is made of rubber valve disc.

[0014] Preferably, the edge of the rubber valve disc is provided with a sealing skirt covering the air hole. The sealing skirt fits against the inner wall of the secondary or tertiary expansion tube to increase the sealing area between the rubber valve disc and the tube wall and prevent outside air from leaking from the edge of the valve disc.

[0015] Preferably, the nozzle, connecting pipe, primary expansion pipe, secondary expansion pipe and tertiary expansion pipe are inserted in sequence, and the insertion position is sealed with an O-ring.

[0016] Preferably, the inner walls of the primary flow channel, secondary flow channel, and tertiary flow channel are all mirror-polished smooth surfaces.

[0017] The high-vacuum three-stage vacuum generator provided in this embodiment has the following beneficial effects: This invention solves the problem of low acceleration and entrainment efficiency of traditional single-stage / two-stage flow channels in high-altitude and low-pressure environments by using a three-stage differentiated flow channel, multi-gap entrainment combined with an air hole inlet structure. It can efficiently convert compressed air into a high-speed jet and form a stable negative pressure, thereby improving the vacuuming speed in high-altitude areas and saving energy. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic cross-sectional view of the present invention. Figure 3 This is a schematic diagram of the nozzle structure in this utility model. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0020] See Figures 1-3 To address the problems mentioned in the background section, this utility model provides a high-vacuum three-stage vacuum generator to solve the aforementioned technical problems. The technical solution is as follows: A high-vacuum three-stage vacuum generator includes a nozzle 1, a connecting pipe 2, a first-stage expansion pipe 3, a second-stage expansion pipe 4, and a third-stage expansion pipe 5 connected in series along the airflow direction; The first-stage expansion tube 3, the second-stage expansion tube 4, and the third-stage expansion tube 5 are all hollow tubes, and their interiors are respectively provided with a first-stage flow channel 3-3, a second-stage flow channel 4-3, and a third-stage flow channel 5-1 along the tube axis; The cross-section of the primary flow channel 3-3 has a gradually contracting structure from its inlet end to its outlet end; The cross-section of the secondary flow channel 4-3 has a gradually expanding structure from its inlet end to its outlet end; The cross-section of the three-stage flow channel 5-1 has a gradually expanding structure from its inlet end to its outlet end. The inlets of the primary flow channel 3-3, the secondary flow channel 4-3, and the tertiary flow channel 5-1 are all connected to the external environment of the vacuum generator through air holes opened on the corresponding pipe walls, and one-way valves are installed at the air holes of the secondary expansion tube 4 and the tertiary expansion tube 5.

[0021] In this embodiment, the nozzle 1 has an integrated flow channel that runs through the airflow direction. The integrated flow channel includes a compressed air inlet section 1-1 and a nozzle section connected in sequence. The nozzle section includes a contraction section 1-2 and an expansion section 1-3 connected in sequence along the airflow direction.

[0022] In this embodiment, the flow channel cross-section of the contraction section 1-2 gradually contracts from the compressed air inlet section 1-1 to the expansion section 1-3; the flow channel cross-section of the expansion section 1-3 gradually expands from the tail of the compressed air inlet section 1-1 to the tail of the expansion section 1-3.

[0023] The contraction section 1-2 gradually contracts through the flow channel cross-section, initially accelerating the compressed air from high pressure and low speed to medium pressure and medium speed, preparing for further acceleration of the subsequent airflow; the expansion section 1-3 gradually expands through the flow channel cross-section, accelerating the airflow to supersonic speed, enhancing the kinetic energy of the airflow to strengthen the entrainment effect of the first gap.

[0024] In this embodiment, the nozzle 1 and the first-stage expansion pipe 3 are fixedly connected to both sides of the connecting pipe 2 respectively; there is a first gap 5-1 between the air outlet end of the nozzle 1 and the air inlet end of the first-stage flow channel 3-3, and a first air hole 2-1 is provided on the pipe wall of the connecting pipe 2.

[0025] The first gap 5-1 between the air outlet of nozzle 1 and the air inlet of primary flow channel 3-3 can work with the high-speed airflow output by the nozzle to form a negative pressure, providing space for air entrainment.

[0026] The first air hole 2-1 on the wall of the connecting pipe 2 can introduce outside air into the first gap 5-1, mix it with the high-speed airflow, and then enter the primary flow channel to replenish the air volume in the high-altitude environment and enhance the vacuuming capacity of the subsequent flow channels.

[0027] In this embodiment, the two sides of the primary expansion tube 3 are respectively fixedly connected to the connecting tube 2 and the secondary expansion tube 4; there is a second gap 5-2 between the air outlet end of the primary flow channel 3-3 and the air inlet end of the secondary flow channel 4-3; a second air hole 3-1 is provided on the tube wall of the primary expansion tube 3; and a first one-way valve 3-1 is provided on the second air hole 3-2.

[0028] The second gap 5-2 between the air outlet of the primary flow channel 3-3 and the air inlet of the secondary flow channel 4-3, together with the high-speed airflow, forms a negative pressure, providing space for entraining air.

[0029] The second vent 3-1 can introduce outside air to supplement the airflow, and the first one-way valve 3-1 can prevent reverse leakage of airflow, ensuring the stability and efficiency of vacuuming in high-altitude environments.

[0030] In this embodiment, a primary expansion tube 3 and a tertiary expansion tube 5 are fixedly connected to both sides of the secondary expansion tube 4, respectively; there is a third gap 5-3 between the air outlet of the secondary flow channel 4-3 and the air inlet of the tertiary flow channel 5-1; a third air hole 3-3 is provided on the pipe wall of the secondary expansion tube 4; and a second one-way valve 3-2 is provided on the third air hole 3-3.

[0031] The third gap 5-3 between the air outlet of the secondary flow channel 4-3 and the air inlet of the tertiary flow channel 5-1, together with the high-speed airflow, forms a negative pressure, providing the necessary space for entraining air.

[0032] The third vent 3-3 can introduce outside air to supplement the airflow, and the second one-way valve 3-2 can prevent airflow from leaking in the opposite direction, further improving the efficiency and stability of vacuuming in high-altitude environments.

[0033] In this embodiment, a rubber valve disc is selected for the one-way valve; the rubber material has good elasticity and can automatically open with negative air pressure and automatically close with positive pressure, adapting to the dynamic changes in air pressure in high-altitude environments and responding sensitively.

[0034] In this embodiment, the edge of the rubber valve disc is provided with a sealing skirt that covers the air hole. The sealing skirt is in contact with the inner wall of the secondary expansion tube 4 or the tertiary expansion tube 5 to increase the sealing area between the rubber valve disc and the tube wall and prevent outside air from leaking from the edge of the valve disc.

[0035] In this embodiment, the nozzle 1, connecting pipe 2, primary expansion pipe 3, secondary expansion pipe 4 and tertiary expansion pipe 5 are inserted sequentially, and the insertion positions are sealed with O-rings.

[0036] In this embodiment, the inner walls of the primary flow channel 3-3, the secondary flow channel 4-3, and the tertiary flow channel 5-1 are all mirror-polished smooth surfaces; the smooth surfaces can reduce airflow friction resistance and ensure that the mixed airflow is smoothly discharged from the vacuum generator.

[0037] The working process of a high-vacuum three-stage vacuum generator provided in this embodiment is as follows: (1) External compressed air is introduced into the integrated flow channel inside the nozzle 1 through the compressed air inlet section 1-1. It first enters the contraction section 1-2 of the nozzle section. The flow channel cross section of the contraction section 1-2 gradually contracts from the compressed air inlet section 1-1 to the expansion section 1-3, which initially accelerates the compressed air. Then the airflow enters the expansion section 1-3. The flow channel cross section of the expansion section 1-3 gradually expands from the tail of the contraction section 1-2 to its own tail, further accelerating the airflow to a high-speed jet state.

[0038] (2) When the high-speed jet flows through the first gap 5-1, a negative pressure entrainment effect will be generated; at this time, the outside air is drawn into the first gap 5-1 through the first air hole 2-1 on the wall of the connecting pipe 2, and after mixing with the high-speed jet, it enters the first-stage flow channel 3-3 together. The flow channel cross section of the first-stage flow channel 3-3 has a gradually contracting structure from the air inlet end to the air outlet end. The mixed airflow is further accelerated in the contracting flow channel, and then output from the air outlet end of the first-stage flow channel 3-3 to the second gap 5-2 between it and the second-stage expansion pipe 4, forming a negative pressure entrainment again; the outside air is drawn in through the second air hole 3-1 on the wall of the first-stage expansion pipe 3, and the first one-way valve at the second air hole 3-1 is opened under the action of negative pressure, ensuring that the air smoothly enters the second gap 5-2, mixes with the airflow, and enters the second-stage flow channel 4-3.

[0039] (3) The cross-section of the secondary flow channel 4-3 has a gradually expanding structure from the inlet end to the outlet end. The airflow maintains high speed and negative pressure in the expansion channel. When the airflow passes through the third gap 5-3 between the outlet end of the secondary flow channel 4-3 and the tertiary expansion tube 5, the entrainment effect continues to occur. Outside air is drawn in through the third air hole 3-3 on the wall of the secondary expansion tube 4. The second one-way valve at the third air hole 3-3 opens simultaneously. After the air enters the third gap 5-3 and mixes with the airflow, it finally enters the tertiary flow channel 5-1. Then the mixed airflow is smoothly discharged from the end of the tertiary flow channel 5-1 outside the vacuum generator.

[0040] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0041] In this utility model, unless otherwise explicitly specified and limited, the terms "installation", "setting", "connection", "fixing", "screw connection", etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0042] It is understood that those skilled in the art can make equivalent substitutions or changes based on the technical solution and concept of this utility model, and all such substitutions or changes should fall within the protection scope of the appended claims.

Claims

1. A high-vacuum three-stage vacuum generator, characterized in that, It includes a nozzle, a connecting pipe, a first-stage expander, a second-stage expander, and a third-stage expander connected in series along the airflow direction; The primary, secondary, and tertiary expansion tubes are all hollow tubes, and each has a primary flow channel, a secondary flow channel, and a tertiary flow channel respectively arranged along the tube axis. The cross-section of the primary flow channel has a gradually contracting structure from its inlet end to its outlet end; The cross-section of the secondary flow channel has a gradually expanding structure from its inlet end to its outlet end; The cross-section of the three-stage flow channel has a gradually expanding structure from its inlet end to its outlet end. The inlets of the primary, secondary, and tertiary flow channels are all connected to the external environment of the vacuum generator through vents opened on the corresponding pipe walls, and one-way valves are installed at the vents of the secondary and tertiary expansion tubes.

2. The high-vacuum three-stage vacuum generator according to claim 1, characterized in that, The nozzle has an integrated flow channel that runs through the airflow direction. The integrated flow channel includes a compressed air inlet section and a nozzle section connected in sequence. The nozzle section includes a contraction section and an expansion section connected in sequence along the airflow direction.

3. The high-vacuum three-stage vacuum generator according to claim 2, characterized in that, The flow channel cross-section of the contraction section gradually shrinks from the compressed air inlet section to the expansion section; the flow channel cross-section of the expansion section gradually expands from the tail of the compressed air inlet section to the tail of the expansion section.

4. The high-vacuum three-stage vacuum generator according to claim 1, characterized in that, The nozzle and the first-stage expansion tube are fixed to both sides of the connecting pipe, respectively; there is a first gap between the air outlet end of the nozzle and the air inlet end of the first-stage flow channel, and a first air hole is provided on the pipe wall of the connecting pipe.

5. The high-vacuum three-stage vacuum generator according to claim 1, characterized in that, A connecting pipe and a secondary expansion pipe are fixedly connected to both sides of the primary expansion pipe, respectively; there is a second gap between the air outlet of the primary flow channel and the air inlet of the secondary flow channel; a second air hole is provided on the pipe wall of the primary expansion pipe, and a first one-way valve is provided on the second air hole.

6. The high-vacuum three-stage vacuum generator according to claim 1, characterized in that, The first-stage expansion tube and the third-stage expansion tube are fixed to both sides of the second-stage expansion tube respectively; there is a third gap between the air outlet of the second-stage flow channel and the air inlet of the third-stage flow channel; a third air hole is provided on the tube wall of the second-stage expansion tube, and a second one-way valve is provided on the third air hole.

7. The high-vacuum three-stage vacuum generator according to claim 1, characterized in that, The check valve uses a rubber valve disc.

8. The high-vacuum three-stage vacuum generator according to claim 7, characterized in that, The edge of the rubber valve disc is provided with a sealing skirt that covers the air vent. The sealing skirt fits against the inner wall of the secondary or tertiary expansion tube to increase the sealing area between the rubber valve disc and the tube wall and prevent outside air from leaking from the edge of the valve disc.

9. The high-vacuum three-stage vacuum generator according to claim 1, characterized in that, The nozzle, connecting pipe, primary expansion pipe, secondary expansion pipe and tertiary expansion pipe are inserted in sequence, and the insertion points are sealed with O-rings.

10. The high-vacuum three-stage vacuum generator according to claim 1, characterized in that, The inner walls of the primary, secondary, and tertiary flow channels are all mirror-polished smooth surfaces.

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