Mass flow control system

Abstract

The utility model relates to the technical field of MFC, in particular to a mass flow control system which comprises a valve seat, an execution structure and a laminar flow structure. An airflow channel is arranged in the valve seat, the output end of the execution structure opens and closes the airflow channel, and the airflow channel is divided into a first circulation part and a second circulation part in the disconnection state; the second circulation part comprises a containing space for containing the laminar flow structure and a middle air channel located between the output end of the execution structure and the laminar flow structure; in the plane perpendicular to the forming direction of the middle air channel, the area projection defined by the outer contour of the containing space completely covers the area projection defined by the outer contour of the middle air channel, so that the middle air channel is more convenient to form, and the machining difficulty and the machining cost are greatly reduced; and meanwhile, the valve seat does not need to be constructed into a split structure, so that assembly is not needed, the middle transition design is reduced, the sealing problem of a plurality of components is reduced, the air leakage risk is reduced, and the sealing performance of the valve seat can be fully guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of MFC technology, and in particular to a mass flow control system. Background Technology

[0002] Mass flow controllers (MFCs) are used for precise measurement and control of fluid mass flow rates. In addition to the functions of a mass flow meter, and more importantly, they can automatically control gas flow rates. Users can set flow rates as needed, and the MFC will automatically maintain a constant flow rate at the set value. Even if system pressure fluctuates or ambient temperature changes, the MFC can keep the flow rate within the set value, thus ensuring flow stability. In practical applications, MFCs achieve precise flow control by incorporating components such as proportional valves and laminar flow meters, both of which are mounted on valve seats.

[0003] Therefore, the valve seat of the MFC needs to have through holes for fluid flow and also needs to have a accommodating space for the laminar flow structure to be accommodated. Figure 1 As shown, in the prior art, the bottom of the accommodating space for the laminar flow structure is opened to H1, which makes it very difficult to process the through hole structure from point A to point B. In practical applications, the valve seat needs to be designed as a split structure and assembled. Therefore, the prior art not only needs to consider the assembly process, but also the sealing performance. This application develops a mass flow control system to solve the problems existing in the prior art. Utility Model Content

[0004] The purpose of this invention is to provide a mass flow control system that solves the problem of the difficulty in processing the internal accommodating space of the MFC valve seat in the prior art, which requires it to be set as a split structure, and further solves the problems of complicated assembly process and poor sealing performance in the prior art.

[0005] The technical solution of this utility model is: a mass flow control system, including a valve seat, an actuator, and a laminar flow structure;

[0006] The valve seat is provided with an airflow channel. The output end of the actuator switches the airflow channel on and off, and in the off state, the airflow channel is divided into a first flow section and a second flow section.

[0007] The second flow section includes a accommodating space for the laminar flow structure to be accommodated, and an intermediate air passage located between the output end of the execution structure and the laminar flow structure; in a plane perpendicular to the opening direction of the intermediate air passage, the projection of the area formed by the outer contour of the accommodating space completely covers the projection of the area formed by the outer contour of the intermediate air passage, thereby making the valve seat a single structure.

[0008] Preferably, in a plane perpendicular to the opening direction of the intermediate air passage, the projection of the laminar flow structure is offset from the area enclosed by the outer contour of the intermediate air passage; wherein, the lower end face of the laminar flow structure is raised and its height is higher than the lower end face of the intermediate air passage, and a sealing element is provided between the lower end face of the laminar flow structure and the lower end face of the accommodating space.

[0009] Preferably, the opening direction of the accommodating space is perpendicular to the opening direction of the intermediate airway, and the upper end of the accommodating space is open.

[0010] Preferably, the accommodating space has a set of support parts, the support parts having a support surface arranged in a horizontal direction and a wall surface arranged in a vertical direction, the laminar flow structure is supported on the support surface, and the space between a pair of the walls is opposite to the intermediate air passage.

[0011] Preferably, the pair of said walls have at least one set of oppositely arranged grooves, the seal being embedded in the grooves and blocking the space between the pair of said walls.

[0012] Preferably, the second circulation section further includes a first air inlet and outlet, and the intermediate air passage and the first air inlet and outlet are respectively disposed on both sides of the accommodating space;

[0013] The first circulation section includes a second air inlet and outlet;

[0014] The first air inlet / outlet, the accommodating space, the intermediate air passage, and the second air inlet / outlet are connected in sequence.

[0015] Preferably, the laminar flow structure includes a laminar flow pad, a laminar flow plate module, and a laminar flow plate pressure plate arranged sequentially from bottom to top; the laminar flow plate module forms a plurality of laminar flow channels and realizes the flow between the intermediate air passage and the first air inlet / outlet.

[0016] Preferably, a detection chamber with equal pressure to the laminar flow channel is formed above the laminar flow plate, and a pressure sensor and / or differential pressure sensor are installed in the detection chamber.

[0017] Preferably, the actuator, pressure sensor, and differential pressure sensor are covered with a housing and have a built-in circuit board. The circuit board has a connector extending to the housing for external connection.

[0018] Compared with the prior art, the advantages of this utility model are:

[0019] (1) By increasing the opening depth of the accommodating space, this application makes the area projection formed by the outer contour of the accommodating space fully cover the area projection formed by the outer contour of the intermediate air passage, thereby making the opening of the intermediate air passage more convenient and greatly reducing the processing difficulty and processing cost; there is no need to construct the valve seat as a split structure, and therefore no need to assemble, reducing the intermediate transition design, reducing the sealing problems of multiple components, reducing the risk of air leakage, and ensuring that the sealing performance of the valve seat can be fully guaranteed.

[0020] (2) By increasing the opening depth, the laminar flow structure needs to be raised relative to the bottom of the accommodating space, and the accommodating space at the lower end of the laminar flow structure is blocked by the seal; therefore, a support part is further provided. The support part can not only facilitate the support of the laminar flow structure, but also facilitate the embedding of the seal to ensure the structural strength; at the same time, the seal can effectively isolate the accommodating space at the front and rear ends of the laminar flow structure, which is beneficial to the consistency, stability and accuracy of the sensor detection pressure. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0022] Figure 1 This is a cross-sectional view of a mass flow control system according to the present invention.

[0023] Figure 2 This is a cross-sectional view of the valve seat and laminar flow structure described in this utility model;

[0024] Figure 3 This is a schematic diagram of the structure of the valve seat described in this utility model.

[0025] Among them: 1. Valve seat;

[0026] 11. First circulation section; 111. Second air inlet / outlet;

[0027] 12. Second circulation section; 121. Intermediate air passage; 122. Containment space; 123. First air inlet / outlet;

[0028] 13. Sealing components;

[0029] 14. Supporting part; 141. Supporting surface; 142. Wall surface;

[0030] 2. Execution structure;

[0031] 3. Laminar flow structure;

[0032] 31. Laminar flow pad; 32. Laminar flow plate module; 33. Laminar flow plate pressure plate; 34. Detection chamber; 35. Pressure sensor; 36. Differential pressure sensor.

[0033] 4. Outer shell;

[0034] 41. Control circuit board; 42. Connector. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to specific embodiments:

[0036] like Figure 1 As shown, a mass flow control system includes a valve seat 1, an actuator 2, and a laminar flow structure 3; the actuator 2 and the valve seat 1 are assembled to form a proportional valve, and the laminar flow structure 3 is used to ensure the stability of the fluid flow rate.

[0037] Combination Figure 2 As shown, an airflow channel is provided inside the valve seat 1. The output end of the actuator 2 opens and closes the airflow channel, and in the open state, the airflow channel is divided into a first flow section 11 and a second flow section 12.

[0038] The first flow section 11 includes a second air inlet / outlet 111, which is opened horizontally from the side wall of the valve seat 1; the second flow section 12 includes a accommodating space 122 for the laminar flow structure 3 to be accommodated, and an intermediate air passage 121 located between the output end of the actuator 2 and the laminar flow structure 3, and also includes a first air inlet / outlet 123, with the intermediate air passage 121 and the first air inlet / outlet 123 respectively located on both sides of the accommodating space 122; the first air inlet / outlet 123, the accommodating space 122, the intermediate air passage 121, and the second air inlet / outlet 111 are connected in sequence.

[0039] In the traditional structure, reference Figure 1 As shown, the opening depth of the accommodating space 122 is relatively small, that is, the height of the bottom of the accommodating space 122 is H1. At this time, it would be very difficult to open the intermediate air passage 121, so the valve seat 1 needs to be designed as a split structure. In this application, however, in the plane perpendicular to the opening direction of the intermediate air passage 121, the projection of the area formed by the outer contour of the accommodating space 122 completely covers the projection of the area formed by the outer contour of the intermediate air passage 121, thereby making the valve seat 1 a single structure. In this embodiment, the opening direction of the intermediate air passage 121 is horizontal, and the plane perpendicular to the opening direction of the intermediate air passage 121 is vertical. This vertical plane is parallel to the side walls at both ends of the valve seat 1. At this time, the height of the bottom of the accommodating space 122 is H2, and the height of the bottom of the accommodating space 122 is not higher than the height of the lowest point of the intermediate air passage 121. Therefore, the opening of the intermediate air passage 121 is directly from point C to point B, which greatly reduces the processing difficulty and can also reduce the processing cost of the valve body. At this point, the valve body does not need to be designed in separate parts, making the structure simpler. Compared with the traditional structure, it reduces the transition design between separate parts, reduces the sealing problems of multiple components, lowers the risk of air leakage, and can even make the product size smaller and the application scenarios wider.

[0040] After increasing the depth of the accommodating space 122, the laminar flow structure 3 still needs to be maintained at the height corresponding to H1, so that the projection of the laminar flow structure 3 and the area enclosed by the outer contour of the intermediate air passage 121 are staggered in the plane perpendicular to the opening direction of the intermediate air passage 121. Therefore, the lower end face of the laminar flow structure 3 needs to be raised, and its height is higher than the lower end height of the intermediate air passage 121. Therefore, a sealing element 13 is provided between the lower end face of the laminar flow structure 3 and the lower end face of the accommodating space 122 to block the accommodating space 122 at the front and rear ends of the laminar flow structure 3.

[0041] Combination Figure 3 As shown, the opening direction of the accommodating space 122 is perpendicular to the opening direction of the intermediate air passage 121, and the upper end of the accommodating space 122 is open. The accommodating space 122 has a set of support portions 14, each having a horizontally arranged support surface 141 and a vertically arranged wall surface 142. The laminar flow structure 3 is supported on the support surface 141. The space between the pair of wall surfaces 142 is opposite to the intermediate air passage 121. At least one set of oppositely arranged grooves are provided on each pair of wall surfaces 142, and a sealing member 13 is embedded in the groove, blocking the space between the pair of wall surfaces 142. In this embodiment, two sealing members 13 are provided, and two sets of grooves are opened on each pair of wall surfaces 142 for the installation of the two sealing members 13 respectively. The two sealing members 13 can achieve double sealing, effectively ensuring the blocking effect of the space at the lower end of the laminar flow structure 3.

[0042] In this embodiment, the support part 14 not only facilitates the support of the laminar flow structure 3, but also facilitates the embedding of the seal 13 to ensure structural strength; at the same time, the seal 13 can effectively isolate the accommodating space 122 at the front and rear ends of the laminar flow structure 3, which is beneficial to the consistency, stability and accuracy of the pressure detected by the sensor (pressure sensor 35 / differential pressure sensor 36).

[0043] The laminar flow structure 3 includes, from bottom to top, a laminar flow pad 31, a laminar flow plate module 32, and a laminar flow plate pressure plate 33. The laminar flow plate module 32 forms several laminar flow channels, enabling flow between the intermediate air passage 121 and the first air inlet / outlet 123. Above the laminar flow plate pressure plate 33, a detection chamber 34 with equal pressure at positions corresponding to the laminar flow channels is formed. The detection chamber 34 is equipped with a pressure sensor 35 and / or a differential pressure sensor 36.

[0044] In practical applications, if the fluid flow direction is set from the second inlet / outlet 111 to the first inlet / outlet 123, then with the proportional valve open, the fluid first enters the second inlet / outlet 111, reaches the intermediate air passage 121, enters the laminar flow channel, and then reaches the first inlet / outlet 123 from the laminar flow channel. Throughout the flow process, the sealing element 13 ensures that all fluid flows through the laminar flow channel. Based on the pressure sensor 35 and the differential pressure sensor 36, precise differential pressure measurement is achieved. Combined with the front-end proportional valve, this forms a precise flow and pressure detection instrument with consistency, stability, and accuracy, enabling precise flow control.

[0045] To ensure structural integrity, the actuator 2, pressure sensor 35, and differential pressure sensor 36 are covered by a housing 4, which houses a control circuit board 41 (PCB). A connector 42 extends from the control circuit board 41. In this embodiment, the connector 42 can be a JST connector for external use with MFC.

[0046] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. It is obvious to those skilled in the art that this utility model is not limited to the details of the above exemplary embodiments, and that it can be implemented in other specific forms without departing from the spirit or basic characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of this utility model is defined by the appended claims rather than the foregoing description, and therefore, all changes falling within the meaning and scope of the equivalents of the claims are intended to be included within this utility model.

Claims

1. A mass flow control system characterized by, The valve seat, the execution structure and the laminar flow structure are included. The valve seat is provided with an airflow channel, and the output end of the execution structure opens and closes the airflow channel and separates the airflow channel into a first flow passage and a second flow passage in the disconnected state. The second flow passage includes a containing space for accommodating the laminar flow structure, and an intermediate air passage between the output end of the execution structure and the laminar flow structure; in a plane perpendicular to the opening direction of the intermediate air passage, the projection of the area surrounded by the outer contour of the containing space fully covers the projection of the area surrounded by the outer contour of the intermediate air passage, so that the valve seat is configured as an integrated structure.

2. A mass flow control system as defined in claim 1, wherein: In a plane perpendicular to the opening direction of the intermediate air passage, the projection of the laminar flow structure is arranged staggered with the area surrounded by the outer contour of the intermediate air passage; wherein the lower end surface of the laminar flow structure is raised, and the height is higher than the height of the lower end part of the intermediate air passage, and a sealing element is arranged between the lower end surface of the laminar flow structure and the lower end surface of the containing space.

3. A mass flow control system as defined in claim 2, wherein: The opening direction of the containing space is perpendicular to the opening direction of the intermediate air passage, and the upper end of the containing space is open.

4. A mass flow control system as defined in claim 3, wherein: The containing space has a set of support parts, the support parts have a support surface arranged in the horizontal direction and a wall surface arranged in the vertical direction, the laminar flow structure is supported on the support surface, and the space between a pair of wall surfaces is opposite to the intermediate air passage.

5. A mass flow control system as defined in claim 4, wherein: A pair of wall surfaces has at least one set of oppositely arranged grooves, the sealing element is embedded in the groove, and the space between a pair of wall surfaces is blocked.

6. The mass flow control system of claim 1, wherein: The second flow passage further includes a first air inlet and outlet, and the intermediate air passage and the first air inlet and outlet are arranged on both sides of the containing space. The first flow passage includes a second air inlet and outlet. The first air inlet and outlet, the containing space, the intermediate air passage and the second air inlet and outlet are sequentially communicated.

7. The mass flow control system of claim 1, wherein: The laminar flow structure includes a laminar flow gasket, a laminar flow sheet module and a laminar flow sheet pressing plate arranged from bottom to top; the laminar flow sheet module forms a plurality of laminar flow channels and realizes the flow communication between the intermediate air passage and the first air inlet and outlet.

8. A mass flow control system as defined in claim 7, wherein: A detection chamber with equal pressure corresponding to the laminar flow channel is formed above the laminar flow sheet pressing plate, and a pressure sensor and / or a differential pressure sensor are installed in the detection chamber.

9. A mass flow control system as defined in claim 8, wherein: The outer side of the execution structure, the pressure sensor and the differential pressure sensor is covered with a shell, and an electric circuit board is built-in, the electric circuit board has a connector extending to the shell for external use.

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