A retrieval-free throttle device

Abstract

This invention relates to the field of throttling device technology, and provides a retrieval-free throttling device, including an oil jacket. A central tube is disposed inside the oil jacket, and a connecting pipe is fixedly sleeved to the bottom of the central tube. A throttling component is disposed at the bottom of the connecting pipe. A pressing tube is disposed outside the central tube, and an adjusting component is disposed outside the pressing tube. This invention, by pressing the pressing tube, drives an adjusting ring downwards. The movement of the adjusting ring compresses a spring, increasing the pressure required to push open the first valve, thereby adjusting the throttling device. This simplifies the steps of retrieving, adjusting, and reusing the throttling device after changes in oil reservoir pressure, enabling automatic adjustment. This improves work efficiency and oil reservoir protection during use, thus enhancing extraction effectiveness.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of throttle technology, and more specifically, to a retrieval-free throttle. Background Technology

[0002] A choke is a component in a hydraulic system that controls fluid flow and generates a pressure drop. Various chokes are used in different aspects of industrial construction, each playing its own role. To adapt to the development of major oilfields and based on the well conditions of different blocks within those oilfields, downhole choke technology has been researched and developed as a new technology, resulting in a wide variety of downhole chokes. Downhole chokes can be broadly classified into two types: movable and fixed. Movable downhole chokes can be run into any well section as needed, with adjustable setting positions, making deployment and retrieval convenient and reliable, especially suitable for older wells requiring choke control. Fixed downhole chokes are deployed to positions determined by the downhole working barrel. They have higher pressure differential resistance, better sealing performance, and simpler and more reliable deployment and retrieval operations, making them suitable for use in newly commissioned wells.

[0003] In existing technologies, throttle valves are typically set to a rated pressure value and then placed into multi-layered oil reservoirs for stratified water injection. However, the properties and conditions of the oil layers may change during extraction and water injection. For example, the permeability, pressure, and water cut of the oil layers may change as extraction progresses. These changes can affect the effectiveness and requirements of stratified water injection, necessitating adjustments to the injection process. This requires retrieving the throttle valve, adjusting its pressure, and then re-placeing it. This adjustment process is overly cumbersome and inefficient. Furthermore, because the throttle valve regulates the water flow rate through it using water pressure, its response is slow. Moreover, rapid adjustments to the water flow rate are needed after changes in oil layer properties and conditions. The slow response of the throttle valve can lead to untimely and ineffective pressure control of the oil layer, thus affecting the oil extraction results. Summary of the Invention

[0004] To overcome the above-mentioned defects, the present invention provides a retrieval-free throttle, which has the advantage of rapid adjustment and solves the technical problem that the pressure of the throttle cannot be quickly adjusted in the prior art.

[0005] According to one aspect, at least one embodiment of the present invention provides a retrieval-free throttle, comprising: an oil jacket, wherein a central tube is disposed inside the oil jacket, a connecting tube is fixedly sleeved at the bottom of the central tube, and a throttle component is disposed at the bottom of the connecting tube;

[0006] A pressing tube is provided on the outside of the central tube, and an adjustment component is provided on the outside of the pressing tube;

[0007] An adjusting ring is fixedly connected to the bottom of the pressing tube, a protective plate is provided at the bottom of the adjusting ring, and a flow-blocking component is provided at the bottom of the adjusting ring.

[0008] The bottom of the regulating ring is provided with a connector, and multiple sets of water outlet holes are opened on the outer side of the oil sleeve. A sleeve is fixedly sleeved at the bottom of the connector. If the above structure is in operation, the throttling component, the flow blocking component and the regulating component can move simultaneously by pressing the pressing tube, thereby avoiding the delay of the throttling device when adjusting the water flow pressure and ensuring the balance of the oil layer.

[0009] Preferably, the throttling component includes a first valve, which is movably sleeved on the outside of the connecting pipe. A water outlet column is provided at the bottom of the first valve, and the first valve and the water outlet column abut against each other. The connecting pipe and the water outlet column are interconnected. The two sets of central pipes are interconnected through the connecting pipe and the water outlet column. The water outlet column is threadedly connected to the connector. Multiple sets of water outlet grooves are provided around the water outlet column and the connecting pipe. If the above structure is in operation, the water pressure can drive the first valve to move out to control the water injection.

[0010] Preferably, the flow-blocking component further includes a compression spring, one end of which is fixedly connected to a first valve, and the other end of which is fixedly connected to an adjusting ring. The compression spring is movably sleeved on the outside of the connecting pipe. If the above structure is in operation, the flow-blocking and throttling components can be connected through the compression spring so that they can be adjusted synchronously when adjusting the water flow rate.

[0011] Preferably, the adjusting component includes an upper guide ring, which is fixedly connected to the oil sleeve. The upper guide ring has multiple sets of arcs at its bottom with varying heights. One end of multiple sets of connecting posts is fixedly connected to the bottom of the upper guide ring, and the other end of these connecting posts is fixedly connected to a lower guide ring. The lower guide ring is fixedly connected to the oil sleeve. A movable post is fixedly connected to one side of the pressing tube, and the movable post abuts against the lower end of the upper guide ring. With this structure, during operation, the pressing tube can rotate through the cooperation of the movable post with the upper and lower guide rings. The varying heights of the multiple arc grooves at the bottom of the upper guide ring allow adjustment of the pressing tube's downward pressure by determining which arc top the movable post is positioned at, thereby regulating the water flow output.

[0012] Preferably, the flow-blocking assembly includes multiple sets of push blocks, all of which are fixedly connected to the outside of the pressing tube. A fixed ring is slidably connected to one side of the adjusting ring, and the fixed ring is fixedly connected to the protective plate. A movable ring is rotatably connected to one side of the fixed ring. As such, when the above structure is in operation, the fixed block and other parts can be moved by lifting and lowering the push blocks, thereby controlling the water injection volume and avoiding the need for retrieval and adjustment.

[0013] Preferably, the flow-blocking component includes multiple sets of fixing blocks, all of which are fixedly connected to the top of the moving ring. Multiple flow-blocking plates are fixedly connected to the bottom of the moving ring, and multiple sets of L-shaped connecting plates are fixedly connected to the bottom of the fixing ring. The multiple sets of L-shaped connecting plates are fixedly connected to the oil sleeve. As described above, during operation, the fixing ring and the oil sleeve can be fixed by the L-shaped connecting plates, thereby limiting the water flow so that it can flow out through the water outlet for stratified water injection.

[0014] Preferably, the upper guide ring and the lower guide ring have the same arc shape, and the arc peaks of the upper guide ring and the lower guide ring are staggered. If the above structure is in operation, the staggered arc peaks of the upper guide ring and the lower guide ring can enable the moving column to rotate following the arc when it moves.

[0015] Preferably, the adjusting ring is movably sleeved inside the protective plate, and the protective plate is fixedly connected to the fixing ring. If the above structure is in operation, the internal compression spring can be protected by the protective plate to prevent water flow from eroding and corroding it.

[0016] Preferably, when the baffle plate rotates to its limit position, it will block two-thirds of the water outlet, thereby instantly reducing the water flow output. If the above structure can block the water outlet by rotating the baffle plate during operation, the water flow can be significantly and instantaneously reduced.

[0017] Preferably, the multiple sets of L-shaped connecting plates are located in the middle of the distance between the two sets of flow deflectors. As described above, when the structure is in operation, the L-shaped connecting plates are located in the middle of the distance between the two sets of flow deflectors, so that the flow deflectors will not collide with the L-shaped connecting plates during rotation, thus preventing shearing behavior and affecting normal use.

[0018] The beneficial effects of the embodiments of the present invention are as follows:

[0019] 1. When the internal state of the oil reservoir changes and the pressure of the throttle needs to be changed, the pressing pipe will drive the adjusting ring to press down. After the adjusting ring moves, the pressure spring is compressed, which increases the pressure required to push open the first valve, thereby adjusting the throttle. After the oil reservoir pressure changes, the steps of retrieving, adjusting and putting the throttle back into use are simplified, enabling it to adjust automatically. This improves work efficiency and the protection of the oil reservoir, thus improving the mining effect.

[0020] 2. This invention uses a pressing tube to drive a pushing block downwards. During the downward pressing process, the pushing block cooperates with the fixed block. Because the moving column of the pressing tube rotates along the arc of the lower and upper guide rings, it drives the pushing block to rotate. The rotation of the pushing block drives the moving ring and the baffle plate to rotate. After the baffle plate rotates, it blocks the water outlet. When the state of the oil layer changes and it is necessary to reduce the output of water for layered injection into the oil layer, the water output can be controlled instantly, realizing instantaneous adjustment of the water injection output. During operation, it can prevent the oil layer from being damaged by excessive water injection, and better maintain the oil layer pressure balance, preventing the formation of cracks or micro-cracks in the oil layer due to excessive pressure, which could damage the original structure of the oil layer. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are merely some exemplary embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the exemplary embodiments of the present invention and these drawings without any creative effort.

[0022] Figure 1 This is an internal sectional view of the oil sleeve of the present invention;

[0023] Figure 2 This is an internal sectional view of the connector of the present invention;

[0024] Figure 3 For the present invention Figure 2 Enlarged view of the structure at point A in the middle;

[0025] Figure 4 This is a schematic diagram of the throttling component structure of the present invention;

[0026] Figure 5 This is a schematic diagram of the water outlet of the present invention;

[0027] Figure 6 This is a schematic diagram of the upper guide ring of the present invention;

[0028] Figure 7 This is a schematic diagram of the moving ring structure of the present invention;

[0029] Figure 8 This is a schematic diagram of the structure of the L-shaped connecting plate of the present invention.

[0030] The components are: 1. Oil sleeve; 2. Central tube; 3. Connecting tube; 4. First valve; 5. Water outlet column; 6. Water outlet trough; 7. Connector; 8. Pressing tube; 9. Adjusting ring; 10. Protective plate; 11. Compression spring; 12. Upper guide ring; 13. Connecting column; 14. Lower guide ring; 15. Moving column; 16. Pushing block; 17. Fixed ring; 18. Moving ring; 19. Fixed block; 20. Baffle plate; 21. Water outlet hole; 22. Sleeve; 23. L-shaped connecting plate. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it.

[0032] To keep the drawings concise, each drawing only schematically shows the parts relevant to the invention; these do not represent the actual structure of the product. Furthermore, for ease of understanding, in some drawings, only one of components with the same structure or function is schematically shown, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one," and "several" includes "two" and "more than two."

[0033] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0035] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of description and simplification of operation, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0036] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0037] like Figures 1-8 As shown, it illustrates a retrieval-free throttle device according to an embodiment of the present invention, including an oil sleeve 1, a central tube 2 disposed inside the oil sleeve 1, a connecting tube 3 fixedly sleeved at the bottom of the central tube 2, and a throttle component disposed at the bottom of the connecting tube 3.

[0038] A pressing tube 8 is provided on the outside of the central tube 2, and an adjustment component is provided on the outside of the pressing tube 8;

[0039] An adjusting ring 9 is fixedly connected to the bottom of the pressing tube 8. A protective plate 10 is provided at the bottom of the adjusting ring 9. A flow-blocking component is provided at the bottom of the adjusting ring 9.

[0040] The bottom of the regulating ring 9 is provided with a connector 7, and multiple sets of water outlet holes 21 are opened on the outer side of the oil sleeve 1. The bottom of the connector 7 is fixedly sleeved with a sleeve 22. By pressing the pressing tube 8, the throttling component, the flow blocking component and the regulating component move simultaneously, thereby avoiding the delay of the throttling device when regulating the water flow pressure and ensuring the balance of the oil layer.

[0041] The throttling component includes a first valve 4, which is movably sleeved on the outside of the connecting pipe 3. A water outlet column 5 is provided at the bottom of the first valve 4. The first valve 4 and the water outlet column 5 abut against each other. The connecting pipe 3 and the water outlet column 5 are interconnected. Two sets of central pipes 2 are interconnected through the connecting pipe 3 and the water outlet column 5. The water outlet column 5 is threadedly connected to the connector 7. Multiple sets of water outlet grooves 6 are opened around the water outlet column 5 and the connecting pipe 3. The throttling component also includes a compression spring 11. One end of the compression spring 11 is fixedly connected to the first valve 4, and the other end of the compression spring 11 is fixedly connected to the adjusting ring 9. The compression spring 11 is movably sleeved on the outside of the connecting pipe 3.

[0042] When the internal state of the oil reservoir changes and the pressure of the throttle needs to be changed, the pressing pipe 8 will drive the adjusting ring 9 to press down. After the adjusting ring 9 moves, the pressure spring 11 is compressed, which increases the pressure required to push open the first valve 4, thereby adjusting the throttle. After the oil reservoir pressure changes, the steps of retrieving, adjusting and putting the throttle back into use are simplified, enabling it to adjust automatically. This improves work efficiency and the protection of the oil reservoir, thus improving the mining effect.

[0043] The adjusting assembly includes an upper guide ring 12, which is fixedly connected to the oil sleeve 1. Multiple sets of arcs at the bottom of the upper guide ring 12 have different heights. One end of multiple sets of connecting posts 13 is fixedly connected to the bottom of the upper guide ring 12. The other end of the multiple sets of connecting posts 13 is fixedly connected to a lower guide ring 14, which is fixedly connected to the oil sleeve 1. A movable post 15 is fixedly connected to one side of the pressing tube 8, and the movable post 15 abuts against the lower end of the upper guide ring 12. The flow-blocking assembly includes multiple sets of pushing blocks 16. Block 16 is fixedly connected to the outside of the pressing tube 8. A fixed ring 17 is slidably connected to one side of the adjusting ring 9. The fixed ring 17 is fixedly connected to the protective plate 10. A movable ring 18 is rotatably connected to one side of the fixed ring 17. The flow obstruction assembly includes multiple sets of fixed blocks 19. Multiple sets of fixed blocks 19 are fixedly connected to the top of the movable ring 18. Multiple flow obstruction plates 20 are fixedly connected to the bottom of the movable ring 18. Multiple sets of L-shaped connecting plates 23 are fixedly connected to the bottom of the fixed ring 17. Multiple sets of L-shaped connecting plates 23 are fixedly connected to the oil sleeve 1.

[0044] The pressing tube 8 drives the pushing block 16 to press down. During the pressing process, the pushing block 16 will cooperate with the fixed block 19. Because the moving column 15 of the pressing tube 8 rotates along the arc of the lower guide ring 14 and the upper guide ring 12, it will drive the pushing block 16 to rotate. The rotation of the pushing block 16 can drive the moving ring 18 and the baffle plate 20 to rotate. After the baffle plate 20 rotates, it will block the water outlet 21. When the state of the oil layer changes and it is necessary to reduce the output of water for layered water injection into the oil layer, the output of water can be controlled instantly, realizing instantaneous adjustment of the water injection output. During the operation, it can avoid excessive water injection and prevent the oil layer from being damaged by excessive water injection. At the same time, it can better maintain the pressure balance of the oil layer and prevent the oil layer from cracking or micro-cracks due to excessive pressure, which may damage the original structure of the oil layer.

[0045] The upper guide ring 12 and the lower guide ring 14 have the same arc shape, and the arc peaks of the upper guide ring 12 and the lower guide ring 14 are staggered. The staggered arc peaks of the upper guide ring 12 and the lower guide ring 14 can make the moving column 15 rotate with the arc when it moves, and drive the pressing tube 8 to rotate, so that the flow obstruction component can simultaneously drive the throttling component to control the water flow.

[0046] The adjusting ring 9 is movably sleeved inside the protective plate 10. The protective plate 10 is fixedly connected to the fixing ring 17. The protective plate 10 protects the internal compression spring 11 to prevent water flow from eroding and corroding it, thereby improving its service life.

[0047] When the baffle plate 20 rotates to its limit position, it will block two-thirds of the water outlet 21, thereby instantly reducing the water output. The rotation of the baffle plate 20 blocks the water outlet 21, and the water flow can be significantly reduced instantaneously, thereby improving the throttling effect and enhancing the instantaneous regulation function of the throttling device to avoid damage to the oil layer caused by delayed water flow regulation.

[0048] Among them, multiple sets of L-shaped connecting plates 23 are located in the middle of the distance between the two sets of baffle plates 20. When working, the L-shaped connecting plates 23 are located in the middle of the distance between the two sets of baffle plates 20, so that the baffle plates 20 will not collide with the L-shaped connecting plates 23 during rotation, thus preventing shearing behavior and affecting normal use.

[0049] Working principle:

[0050] When the device is placed inside the oil layer during operation, water is injected into the interior through the pressing pipe 8. The water flows through the central pipe 2 and the connecting pipe 3, and then flows out to the outside of the water column 5 through the water outlet 6. At this time, the water pressure inside the central pipe 2 increases, and the water flow will push out the first valve 4. The first valve 4 slides backward along the outside of the connecting pipe 3, and the water flows into the oil layer through the water outlet 21 to complete the layered water injection work.

[0051] When the internal state of the oil layer changes and the pressure of the throttle needs to be changed, the pressing pipe 8 will drive the adjusting ring 9 to press down. After the adjusting ring 9 moves, the pressure spring 11 is compressed, which increases the pressure required to push open the first valve 4, thereby adjusting the throttle. After the oil layer pressure changes, the steps of retrieving, adjusting and putting the throttle back into use are simplified, so that it can be automatically adjusted. This improves work efficiency and the protection of the oil layer during operation, and improves the mining effect.

[0052] Simultaneously, pressing down on the pressing tube 8 causes the moving column 15 to move. The moving column 15 moves from the top of the arc of the upper guide ring 12 to the trough of the lower guide ring 14. During this movement, it will rotate to some extent due to the curvature of the lower guide ring 14. Releasing the pressure on the pressing tube 8 causes it to move upwards due to the release of the spring force of the compression spring 11. The movement of the pressing tube 8 causes the moving column 15 to leave the trough of the lower guide ring 14. As the pressing tube 8 continues to move upwards, it causes the moving column 15 to contact the curvature of the upper guide ring 12, thus moving to another trough of the upper guide ring 12. During this upward movement, the moving column 15 will also rotate to some extent due to the displacement of the curvature of the upper guide ring 12. At the same time, pressing down on the pressing tube 8 causes the pushing block 16 to press down. During this pressing process, the pushing block 16 will cooperate with the fixed block 19. The pressing tube 8, due to the moving column 15 moving along the lower guide ring 14 and... When the arc of the upper guide ring 12 rotates, it drives the push block 16 to rotate. The rotation of the push block 16 drives the moving ring 18 and the baffle plate 20 to rotate. After the baffle plate 20 rotates, it will block the water outlet 21. When the state of the oil layer changes and it is necessary to reduce the output of water for layered injection into the oil layer, the output of water can be controlled instantly, realizing instantaneous adjustment of the water injection output. During operation, it can prevent the oil layer from being damaged by excessive water injection, and better maintain the oil layer pressure balance. It can also prevent the oil layer from cracking or micro-cracks due to excessive pressure, which could damage the original structure of the oil layer. After the water flow rate is adjusted instantaneously, after the press tube 8 is pushed out and reset, the impact of the water flow will slowly push out the baffle plate 20 to restore itself to the output rate after the adjustment of the flow regulator. The water output will not be reduced due to the obstruction of the baffle plate 20, thus not affecting the water injection effect.

[0053] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A retrieval-free throttle device, characterized in that, include: Oil sleeve (1), the inside of the oil sleeve (1) is provided with a central tube (2), the bottom of the central tube (2) is fixedly sleeved with a connecting tube (3), and the bottom of the connecting tube (3) is provided with a throttling component; A pressing tube (8) is provided on the outside of the central tube (2), and an adjustment component is provided on the outside of the pressing tube (8); An adjusting ring (9) is fixedly connected to the bottom of the pressing tube (8), a protective plate (10) is provided at the bottom of the adjusting ring (9), and a flow-blocking component is provided at the bottom of the adjusting ring (9). The bottom of the adjusting ring (9) is provided with a connector (7), and multiple sets of water outlet holes (21) are opened on the outer side of the oil sleeve (1). The bottom of the connector (7) is fixedly sleeved with a sleeve (22). The throttling component includes a first valve (4), which is movably sleeved on the outside of the connecting pipe (3). A water outlet column (5) is provided at the bottom of the first valve (4). The first valve (4) and the water outlet column (5) abut against each other. The connecting pipe (3) and the water outlet column (5) are interconnected. The two sets of central pipes (2) are interconnected through the connecting pipe (3) and the water outlet column (5). The water outlet column (5) is threadedly connected to the connector (7). Multiple sets of water outlet grooves (6) are opened around the water outlet column (5) and the connecting pipe (3). The flow-blocking assembly also includes a compression spring (11), one end of which is fixedly connected to the first valve (4), and the other end of which is fixedly connected to the adjusting ring (9). The compression spring (11) is movably sleeved on the outside of the connecting pipe (3). The adjustment assembly includes an upper guide ring (12), which is fixedly connected to the oil sleeve (1). The upper guide ring (12) has multiple arcs at the bottom with different heights. The bottom of the upper guide ring (12) is fixedly connected to one end of multiple sets of connecting columns (13). The other end of the multiple sets of connecting columns (13) is fixedly connected to a lower guide ring (14). The lower guide ring (14) is fixedly connected to the oil sleeve (1). A movable column (15) is fixedly connected to one side of the pressing tube (8). The movable column (15) abuts against the lower end of the upper guide ring (12). The flow-blocking assembly includes multiple sets of push blocks (16), all of which are fixedly connected to the outside of the pressing tube (8). A fixed ring (17) is slidably connected to one side of the adjusting ring (9). The fixed ring (17) is fixedly connected to the protective plate (10), and a moving ring (18) is rotatably connected to one side of the fixed ring (17). The flow-blocking assembly includes multiple sets of fixed blocks (19), all of which are fixedly connected to the top of the moving ring (18). Multiple flow-blocking plates (20) are fixedly connected to the bottom of the moving ring (18), and multiple sets of L-shaped connecting plates (23) are fixedly connected to the bottom of the fixed ring (17). The multiple sets of L-shaped connecting plates (23) are fixedly connected to the oil sleeve (1). The upper guide ring (12) and the lower guide ring (14) have the same arc shape, and the arc peaks of the upper guide ring (12) and the lower guide ring (14) are staggered.

2. The retrieval-free throttle device according to claim 1, characterized in that, The adjusting ring (9) is movably sleeved inside the protective plate (10), and the protective plate (10) is fixedly connected to the fixing ring (17).

3. The non-retrieval throttle device according to claim 2, characterized in that, When the baffle plate (20) is rotated to its limit position, the baffle plate (20) will block two-thirds of the water outlet (21) to instantly reduce the output of water flow.

4. The non-retrieval throttle device according to claim 3, characterized in that, The multiple sets of L-shaped connecting plates (23) are located at the middle of the distance between the two sets of flow-blocking plates (20).

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