Vacuum mass flow control device and its control method

Abstract

This invention discloses a vacuum mass flow control device and its control method. The device includes: a housing; a first flow channel disposed within the housing, having a first starting end and a first ending end; a first sensor for acquiring signals from the fluid in the first flow channel; a second flow channel disposed within the housing, having a second starting end and a second ending end; a second sensor for acquiring the vacuum flow rate in the second flow channel; a venturi tube having an inlet end, an outlet end, and a negative pressure suction port; positive pressure fluid flowing out from the first ending end flows through the venturi tube via the inlet end and is drawn into the venturi tube through the negative pressure suction port along with negative pressure fluid at the second ending end, and then flows outward through the outlet end; a regulating valve for adjusting the flow cross-section of the first flow channel; and a controller electrically connected to the regulating valve, the first sensor, and the second sensor. This application improves integration in structure, significantly reduces size, and achieves real-time and precise control.

Description

Technical Field

[0001] This invention relates to the field of semiconductor equipment technology, and in particular to a vacuum mass flow control device and its control method. Background Technology

[0002] With the upgrading of the semiconductor industry and the iteration of equipment, new requirements have been put forward for vacuum flow control technology of gas circulation.

[0003] One existing vacuum flow control technology for gas circulation involves assembling a system consisting of a manual pressure regulating valve, a switching valve, a vacuum generator, and a mass flow sensor. While this system can achieve basic vacuum flow control, it presents several inconveniences in its operation.

[0004] First, existing systems can only change the vacuum flow rate manually. Manual adjustment is inaccurate and lags behind, making real-time and precise adjustment impossible, and real-time monitoring of the vacuum flow rate is also unavailable. Second, each component in the current system is independent and requires connection via piping, resulting in large space requirements, inflexible layout, high manufacturing and installation costs, and inconvenient maintenance. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, the technical problem to be solved by the embodiments of the present invention is to provide a vacuum mass flow control device and its control method, which can at least improve the integration of the vacuum mass flow control device in terms of structure, reduce its size, and achieve real-time and precise control in terms of control.

[0006] The specific technical solution of the embodiments of the present invention is as follows:

[0007] A vacuum mass flow control device includes: a housing; a first flow channel disposed within the housing, having a first starting end and a first ending end, the first starting end being used to connect to a positive pressure gas source; a first sensor for acquiring signals of fluid in the first flow channel; a second flow channel disposed within the housing, having a second starting end and a second ending end, the second starting end being used to connect to peripheral equipment; a second sensor for acquiring vacuum flow rate in the second flow channel; a venturi tube having an inlet end, an outlet end, and a negative pressure suction port; when positive pressure fluid flowing out from the first ending end flows through the venturi tube via the inlet end, it is drawn into the venturi tube along with negative pressure fluid at the second ending end via the negative pressure suction port and then flows outward through the outlet end; a regulating valve for adjusting the flow cross-section of the first flow channel; and a controller electrically connected to the regulating valve, the first sensor, and the second sensor.

[0008] In a preferred embodiment, the controller is configured to: receive a target vacuum flow rate value and compare the target vacuum flow rate value with the vacuum flow rate detected by the second sensor; when the difference between the two exceeds a preset difference, control the control valve to adjust its opening by combining the signal detected by the first sensor and the current opening of the control valve, until the difference between the detected vacuum flow rate and the target vacuum flow rate value is within the preset difference range.

[0009] In a preferred embodiment, the first sensor is a pressure sensor, the control valve is a piezoelectric proportional valve, and the controller controls the opening degree of the piezoelectric proportional valve by adjusting the duty cycle of the piezoelectric proportional valve.

[0010] In a preferred embodiment, a first connector is provided inside the housing, and a hollow cavity is formed inside the first connector to form the first flow channel. Along the fluid flow direction, the detection position of the first sensor is located upstream of the control valve.

[0011] In a preferred embodiment, the first connector is provided with a branch channel that communicates with the first flow channel. The open end of the branch channel is connected to the first flow channel, and the other end is a closed end. The first sensor is installed in the branch channel in a sealed manner.

[0012] In a preferred embodiment, a second connector is further provided inside the housing, the second connector being used to connect the first connector to the control valve.

[0013] In a preferred embodiment, a third connector is further provided inside the housing, and a hollow cavity is formed inside the third connector to form the second flow channel, and the second sensor is disposed in the second flow channel.

[0014] In a preferred embodiment, the housing is further provided with a fourth connector, the fourth connector having a hollow main cavity and a bypass cavity connected to the main cavity. The main cavity is connected to the first end of the first flow channel and is used to seal and install the Venturi tube. The bypass cavity is connected to the second end of the second flow channel.

[0015] In a preferred embodiment, the venturi tube includes a first portion and a second portion sealed within the main cavity, with a confluence gap formed between the first portion and the second portion; the confluence gap is disposed opposite to the bypass cavity.

[0016] In a preferred embodiment, the flow cross-sectional area of ​​the first termination end is smaller than the flow cross-sectional area of ​​the bypass cavity, but larger than the minimum flow cross-sectional area of ​​the venturi tube.

[0017] In a preferred embodiment, the controller includes a circuit board disposed on the side of the housing. A first DIP switch and a second DIP switch are also disposed on the housing side near the circuit board for switching different signal input and output modes.

[0018] A vacuum mass flow control method for the above-mentioned vacuum mass flow control device includes:

[0019] Receive the target vacuum flow rate value and compare the target vacuum flow rate value with the vacuum flow rate detected by the second sensor;

[0020] When the difference between the target vacuum flow rate and the detected vacuum flow rate exceeds a preset difference, the control valve is adjusted by combining the signal detected by the first sensor and the current opening degree of the control valve.

[0021] When the difference between the detected vacuum flow rate and the target vacuum flow rate is within a preset difference range, the control valve is controlled to stop adjusting its opening.

[0022] In a preferred embodiment, the first sensor is a pressure sensor, the control valve is a piezoelectric proportional valve, and the step of controlling the control valve to adjust its opening by combining the signal detected by the first sensor and the current opening degree of the control valve includes:

[0023] The controller sends a PWM drive signal to the piezoelectric proportional valve;

[0024] The opening degree of the piezoelectric proportional valve is controlled by adjusting the duty cycle of the piezoelectric proportional valve.

[0025] The technical solution of the present invention has the following significant beneficial effects:

[0026] This invention replaces the entire vacuum generator with a venturi tube and integrates a first flow channel for positive pressure fluid, a second flow channel for negative pressure fluid, a first sensor for collecting fluid signals in the first flow channel, a second sensor for collecting vacuum flow in the second flow channel, a venturi tube, a regulating valve for adjusting the flow cross-section of the first flow channel, and a controller into a single housing. This design results in a small size, high integration, minimal space requirements during installation, flexible layout, lower manufacturing and installation costs, and easier maintenance.

[0027] In addition, in terms of control, the opening degree of the control valve is adjusted mainly based on the feedback values ​​of the first and second sensors, thereby realizing real-time control and precise adjustment of vacuum mass flow rate, and can also provide feedback on real-time vacuum flow rate values.

[0028] Specific embodiments of the invention are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of the invention can be employed. It should be understood that the embodiments of the invention are not therefore limited in scope. Within the spirit and scope of the appended claims, embodiments of the invention include many changes, modifications, and equivalents. Features described and / or shown for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments. Attached Figure Description

[0029] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely illustrative to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. Those skilled in the art, guided by the teachings of this invention, can select various possible shapes and proportions to implement the invention according to specific circumstances.

[0030] Figure 1 This is a perspective view of a vacuum mass flow control device provided in the embodiments of this application;

[0031] Figure 2 This is a structural schematic diagram of one side of the housing of a vacuum mass flow control device provided in the embodiments of this application;

[0032] Figure 3 This is a schematic diagram showing the distribution of various components inside the housing of a vacuum mass flow control device provided in the embodiments of this application;

[0033] Figure 4 This is a schematic diagram of the internal flow channel of a vacuum mass flow control device provided in the embodiments of this application;

[0034] Figure 5 for Figure 3 Sectional view AA at point I;

[0035] Figure 6 for Figure 3 A schematic diagram of the internal Venturi tube and other structures is shown at point II;

[0036] Figure 7 This is a perspective view of a venturi tube provided in the embodiments of this application;

[0037] Figure 8 This is a schematic diagram illustrating the working principle of a vacuum mass flow control device provided in the application implementation.

[0038] Figure 9 This is a flowchart illustrating the steps of a vacuum mass flow control method provided in the application implementation.

[0039] The reference numerals in the above figures are as follows:

[0040] 10. Shell;

[0041] 20. First connector; 21. First starting end; 22. Branch channel; 23. First sealing ring; 24. First ending end;

[0042] 200. First flow channel;

[0043] 30. Third connector; 31. Second starting end;

[0044] 300. Second flow channel;

[0045] 40. Wiring harness;

[0046] 41. Grooving;

[0047] 50. Second sensor;

[0048] 60. Fourth connecting piece; 61. Main cavity; 62. Bypass cavity; 63. Second sealing ring;

[0049] 70. Second connector;

[0050] 80. Control valve;

[0051] 90. Controller;

[0052] 91. Connector;

[0053] 92. First DIP switch;

[0054] 93. Second DIP switch;

[0055] 94. First sensor;

[0056] 100. Venturi tube; 110. Inlet end; 120. Outlet end; 130. Negative pressure suction inlet; 101. Snap fastener; 102. First part; 103. Second part. Detailed Implementation

[0057] The details of the present invention can be more clearly understood by referring to the accompanying drawings and the description of specific embodiments. However, the specific embodiments of the present invention described herein are for illustrative purposes only and should not be construed as limiting the invention in any way. Under the teachings of this invention, those skilled in the art can conceive of any possible modifications based on the invention, all of which should be considered within the scope of the invention. It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or there may be an intervening element. The terms "mounted," "connected," and "connected" should be interpreted broadly, for example, they can refer to mechanical or electrical connections, or internal communication between two elements, and can be direct or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0059] Please see Figures 1 to 7 This application provides a vacuum mass flow control device, which may include: a housing 10; a first flow channel 200 disposed within the housing 10, having a first starting end 21 and a first ending end 24, the first starting end 21 being used to connect to a positive pressure gas source; a first sensor 94 for acquiring signals of the fluid in the first flow channel 200; a second flow channel 300 disposed within the housing 10, having a second starting end 31 and a second ending end, the second starting end 31 being used to connect to peripheral equipment; and a second sensor 50. Used to collect the vacuum flow rate in the second flow channel 300; Venturi tube 100, having an inlet end, an outlet end, and a negative pressure suction port; when the positive pressure fluid flowing out from the first termination end 24 flows through the Venturi tube 100 through the inlet end, it will be drawn into the Venturi tube 100 through the negative pressure suction port along with the negative pressure fluid at the second termination end, and then flow out through the outlet end; regulating valve 80, used to adjust the flow cross section of the first flow channel 200; controller 90, electrically connected to the regulating valve 80, the first sensor 94, and the second sensor 50.

[0060] In the embodiments of this application, the Venturi tube 100 replaces the entire vacuum generator, and the first flow channel 200 for flowing positive pressure fluid, the second flow channel 300 for flowing negative pressure fluid, the first sensor 94 for collecting fluid signals in the first flow channel 200, the second sensor 50 for collecting vacuum flow in the second flow channel 300, the Venturi tube 100, the regulating valve 80 for adjusting the flow cross section of the first flow channel 200, and the controller 90 are integrated into the same housing 10. This design is small in size, highly integrated, requires little space during installation, is easy to arrange flexibly, has low manufacturing and installation costs, and is easy to maintain in the future.

[0061] In one embodiment of this application, a control valve 80 electrically connected to the controller 90 is used to replace the manual pressure regulating valve, and a first sensor 94 for collecting fluid signals in the first flow channel 200 and a second sensor 50 for collecting vacuum flow in the second flow channel 300 are provided.

[0062] In use, the controller 90 receives the target vacuum flow rate value and compares the target vacuum flow rate value with the vacuum flow rate detected by the second sensor 50. When the difference between the two exceeds a preset difference value, the controller 90 controls the control valve 80 to adjust its opening degree by combining the signal detected by the first sensor 94 and the current opening degree of the control valve 80 until the difference between the detected vacuum flow rate and the target vacuum flow rate value is within the preset difference value range.

[0063] Overall, the vacuum mass flow control device provided in this application mainly adjusts the opening of the control valve 80 based on the feedback values ​​of the first sensor 94 and the second sensor 50, thereby achieving real-time control and precise adjustment of the vacuum mass flow, and can also provide feedback on the real-time vacuum flow value.

[0064] The vacuum mass flow control device provided in this application will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0065] like Figure 3 As shown in the embodiments of this application, the core functional components integrated in the housing 10 of the vacuum mass flow control device mainly include: a first sensor 94, a second sensor 50, a venturi tube 100, a control valve 80, a controller 90, etc.

[0066] Please refer to the following: Figure 1 and Figure 2In this embodiment, the housing 10 can be a hollow structure with a predetermined size. Specifically, the shape and size of the housing 10 can vary depending on the actual application scenario and adaptation environment, and this application does not impose specific limitations here. The size of the housing 10 is equivalent to the size of the entire vacuum mass flow control device. Compared with the existing form of connecting one by one through pipelines, the housing 10 provided by this application can be significantly smaller in size than the existing vacuum mass flow control device.

[0067] A connector 91 for connecting to external devices can be installed on the housing 10. Specifically, the number and function of the connectors 91 can be determined according to the functional requirements of the actual product, and this application does not impose specific limitations here. For example, the connector 91 can be an interface for communicating with external devices to input signals to the vacuum mass flow control device, or for the vacuum mass flow control device to output signals; it can be an interface for powering the vacuum mass flow control device; it can be an interface for other functions; or it can be an integrated interface capable of realizing multiple functions, etc.

[0068] Please refer to the following: Figure 4 and Figure 5 In this embodiment, the first sensor 94 is mainly used to collect fluid signals in the first flow channel 200. Specifically, the first sensor 94 can be a flow sensor, a pressure sensor, or other sensor types that can reflect the flow rate of the fluid in the first flow channel 200.

[0069] Specifically, in the embodiments of this application, when the first sensor 94 is a pressure sensor, it can be an IC chip-level sensor, which is very small in size and requires very little space in the housing 10, thus facilitating the miniaturization design of the entire housing 10. In the following embodiments of this application, the first sensor 94 is mainly illustrated as a pressure sensor; other types of sensors can be used as analogous references, and will not be elaborated on in detail here.

[0070] like Figure 4 As shown, the second sensor 50 can be a mass flow sensor, which can be set in the second flow channel 300 to collect the vacuum flow in the second flow channel 300.

[0071] The control valve 80 can be a piezoelectric proportional valve, and the controller 90 controls the opening degree of the piezoelectric proportional valve by adjusting the duty cycle of the piezoelectric proportional valve.

[0072] When the control valve 80 is a piezoelectric proportional valve, the controller 90 can store the correspondence between the duty cycle and the opening degree of the piezoelectric proportional valve. When the controller 90 compares the target vacuum flow rate with the vacuum flow rate detected by the second sensor 50 and finds that the difference between the two exceeds a preset difference value, it can combine the signal detected by the first sensor 94 and the current opening degree of the control valve 80 to control the opening degree of the control valve 80 until the difference between the detected vacuum flow rate and the target vacuum flow rate is within the preset difference value range. The specific value of this preset difference value is not specifically limited in this application. Theoretically, the closer the actual vacuum flow rate detected by the second sensor 50 is to the target vacuum flow rate value, the better. Ideally, the two can be completely identical. However, due to different application environments, there are different requirements for control accuracy and efficiency. Controlling the preset difference value within a certain range is sufficient to meet the usage requirements.

[0073] In this embodiment, the controller 90 can be integrated into the housing 10. Specifically, the controller 90 may include a circuit board, which is disposed on the side closest to the housing 10. Specifically, the circuit board can be in the form of a PCB board; however, the controller 90 can also be in other forms. The controller 90 can be connected to the first sensor 94, the second sensor 50, and the control valve 80 via a wired connection or a wireless connection.

[0074] In some other embodiments, it is also possible to place the controller 90 outside the housing 10, or to share an existing controller, etc. The specific location and form of the controller 90 can be set according to actual needs, and this application does not make specific limitations here.

[0075] In addition, a first DIP switch 92 and a second DIP switch 93 are provided on the housing 10 side near the circuit board for switching different signal input / output modes. Specifically, the first DIP switch 92 and the second DIP switch 93 can have different states, which can vary depending on the signal type. For example, when a digital signal is received, the first DIP switch 92 and the second DIP switch 93 can be in a first state, and when an analog signal is received, the first DIP switch 92 and the second DIP switch 93 can be in a second state.

[0076] In this embodiment, the housing 10 is provided with a first flow channel 200 and a second flow channel 300. The first flow channel 200 and the second flow channel 300 can be formed by hollow connectors, or by casting inside the housing 10, or by other processes.

[0077] Please refer to the following: Figure 4In the implementation of the application, the first flow channel 200 and the second flow channel 300 are mainly illustrated by the example of the connection component. Other methods can be compared and referred to on this basis. This application will not describe them one by one here.

[0078] Specifically, a first connector 20 is provided inside the housing 10, and a hollow cavity is formed inside the first connector 20 to form the first flow channel 200. Along the fluid flow direction, the detection position of the first sensor 94 is located upstream of the control valve 80.

[0079] Please refer to the following: Figure 2 and Figure 6 The first flow channel 200 has a first starting end 21 and a first ending end 24. The first starting end 21 is used to connect to a positive pressure gas source. Specifically, the first starting end 21 can be connected to an external positive pressure gas source through a sealed connection. This sealed connection can be in the form of a sealing thread. For example, a sealing internal thread is provided on the first starting end 21, and correspondingly, a sealing external thread that mates with the sealing internal thread is provided on the inlet of the positive pressure gas source. Furthermore, the specific form of this sealed connection is not specifically limited herein. Those skilled in the art may make other modifications based on the technical essence of this application, but as long as the function and effect achieved are the same as or similar to those of this application, they should all be covered within the scope of protection of this application.

[0080] The first sensor 94 is located upstream of the control valve 80, near the first starting end 21, and is used to accurately detect the gas pressure supplied by the external positive pressure gas source.

[0081] Please refer to the following: Figure 4 and Figure 5 As shown, specifically, the first connector 20 is provided with a branch channel 22 that communicates with the first flow channel 200. The open end of the branch channel 22 is connected to the first flow channel 200, and the other end is a closed end. The first sensor 94 is installed in the branch channel 22 in a sealed manner.

[0082] As the gas enters from the first initiation end 21, it first flows through the upstream branch channel 22. At this point, pressure data can be collected by the first sensor 94 (taking a pressure sensor as an example) and transmitted to the circuit board. The sensing portion of the pressure sensor can extend into the branch channel 22, while the other main mounting parts can be sealed and fixed using a first sealing ring 23, thus not affecting the sealing performance of the other end of the branch channel 22. The main body of the pressure sensor can be positioned close to the circuit board or directly mounted on it, further improving the integration of the vacuum mass flow device.

[0083] In one embodiment, a second connector 70 is further provided inside the housing 10, the second connector 70 being used to connect the first connector 20 to the control valve 80.

[0084] Specifically, the second connector 70 can also be a structure with a hollow cavity inside, located near the first termination end 24 of the first flow channel 200. Its main function is to connect the control valve 80 into the first flow channel 200 to regulate the opening of the first flow channel 200, thereby changing parameters such as fluid pressure and flow rate within the first flow channel 200. The control valve 80 can be positioned close to the circuit board, or it can be integrated into the circuit board, further improving the integration of the vacuum mass flow device.

[0085] In one embodiment, a third connector 30 may be provided inside the housing 10. The third connector 30 has a hollow cavity inside, which is used to form the second flow channel 300. The second sensor 50 is disposed in the second flow channel 300.

[0086] Specifically, the third connector 30 can be positioned relative to the first connector 20 on the side furthest from the circuit board. The third connector 30 has a hollow cavity inside, forming a second flow channel 300. The second flow channel 300 has a second starting end 31 and a second ending end. The second starting end 31 is used to connect to peripheral devices. Specifically, the second starting end 31 can be connected to the peripheral devices via a sealed connection. This sealed connection can be in the form of a sealing thread. For example, a sealing internal thread is provided at the second starting end 31, and correspondingly, a sealing external thread that mates with the sealing internal thread is provided at the interface of the peripheral device. Furthermore, the specific form of this sealed connection is not specifically limited herein. Those skilled in the art, guided by the technical essence of this application, may make other modifications, but as long as the achieved function and effect are the same as or similar to that of this application, they should be covered within the scope of protection of this application.

[0087] The second sensor 50 (taking a mass flow sensor as an example) is disposed in the second flow channel 300. Specifically, the second sensor 50 may have an inlet and an outlet, both of which are sealed and connected to the second flow channel 300. The second sensor 50 itself can be electrically connected to the circuit board. Specifically, the electrical connection can be in the form of a wire harness 40. In order to avoid the wire harness 40 and provide constraint space for the wire harness 40, slots 41 for avoiding and positioning the wire harness 40 can be provided on the outer surfaces of the first connector 20 and the third connector 30.

[0088] Please refer to the following: Figure 6 and Figure 7 In one embodiment, a fourth connector 60 may be provided inside the housing 10. The fourth connector 60 has a hollow main cavity 61 and a bypass cavity 62 connected to the main cavity 61. The main cavity 61 is connected to the first end 24 of the first flow channel 200 and is used to seal and install the venturi tube 100. The bypass cavity 62 is connected to the second end of the second flow channel 300.

[0089] In this embodiment, the fourth connector 60 is used to install a venturi tube 100, which is mainly used to merge the first flow channel 200 and the second flow channel 300. Specifically, the fourth connector 60 includes a main cavity 61 for installing the venturi tube 100 and a bypass cavity 62 connected to the main cavity 61.

[0090] The main cavity 61 has an inlet side and an outlet side, and the inlet side can be sealed to the first termination end 24 of the first flow channel 200. Specifically, the sealing connection can be achieved by providing a second sealing ring 63 between the first termination end 24 and the inlet side of the main cavity 61. Of course, this application does not specifically limit the specific form of the sealing connection. Those skilled in the art may make other modifications based on the technical essence of this application, but as long as the function and effect achieved are the same as or similar to those of this application, they should be covered within the scope of protection of this application.

[0091] The Venturi tube 100 has an inlet end 110, an outlet end 120, and a negative pressure inlet 130. The inlet end 110 is located on the inlet side of the main cavity 61 and opposite the first termination end 24, serving to receive positive pressure gas flowing in from the first termination end 24. The outlet end 120 is located on the outlet side of the main cavity 61, which is used to discharge the collected fluid. Specifically, the discharged fluid can be connected to a recovery device or directly discharged, depending on the specific composition of the fluid and production requirements; this application does not impose specific limitations here. The negative pressure inlet 130 is located in the middle section of the Venturi tube 100, a section with a smaller inner diameter. The negative pressure inlet 130 can be connected to the second termination end of the second flow channel 300 via a bypass cavity 62 to form a negative pressure airflow in the second flow channel 300.

[0092] It should be noted that the bypass cavity 62 can specifically be a cavity structure with a certain length; of course, it can also be in the form of a bypass opening opened on the main cavity 61. In this case, the cavity portion of the bypass cavity 62 can be formed by the flow channel of the second flow channel 300 near its second termination end. In a specific embodiment, the venturi tube 100 includes a first portion 102 and a second portion 103 sealed in the main cavity 61, with a confluence gap formed between the first portion 102 and the second portion 103; the confluence gap is disposed opposite to the bypass cavity 62.

[0093] In this embodiment, the Venturi tube 100 may include a first portion 102 and a second portion 103 sealed within the main cavity 61. This sealing can be achieved using a sealing ring, or other methods; no specific limitation is made herein. Furthermore, to effectively limit the sealing ring and facilitate the installation and removal of the Venturi tube 100, a snap-fit ​​structure 101 may be provided between the main cavity 61 and the first termination end 24.

[0094] like Figure 7 As shown, the first part 102 has an inlet end 110 at one end, and the second part 103 has an outlet end 120 at one end. The first part 102 and the second part 103 can be connected by threads to achieve relative fixation. Of course, other connection methods, such as snap-fit ​​connections, can also be used to achieve relative fixation. This application does not specifically limit the connection method between the first part 102 and the second part 103. A confluence gap is formed between the first part 102 and the second part 103. The confluence gap can be arranged opposite to the bypass cavity 62. The confluence gap serves as the negative pressure intake port 130 of the venturi tube 100. When the positive pressure airflow supplied by the first flow channel 200 flows in the main cavity 61, a negative pressure is formed in the confluence gap, which drives the airflow in the second flow channel 300.

[0095] It should be noted that: because the part with a smaller inner diameter in the middle of the Venturi tube 100 has a certain length, a certain annular gap is formed between this part and the main cavity 61. After the fluid flows into the annular gap, it will eventually flow out from the inlet gap through the outlet side.

[0096] Furthermore, the flow cross-sectional area of ​​the first termination end 24 can be smaller than the flow cross-sectional area of ​​the bypass cavity 62. The flow cross-sectional area of ​​the first termination end 24 is larger than the minimum flow cross-sectional area of ​​the venturi tube 100.

[0097] In this system, the first termination end 24 serves as the port of the positive pressure flow channel, initially flowing into the Venturi tube 100. Subsequently, a negative pressure airflow is generated in the bypass cavity 62 and enters the Venturi tube 100. Furthermore, the minimum flow cross-sectional area of ​​the Venturi tube 100 is the smallest part of the entire internal flow channel, which is smaller than the flow cross-sectional area of ​​the first termination end 24 and the flow cross-sectional area of ​​the bypass cavity 62, thereby facilitating the formation of a larger negative pressure adsorption effect at this minimum flow cross-sectional area.

[0098] Please refer to the following: Figure 8 and Figure 9 Based on the vacuum mass flow control device provided in the above embodiments, this application also provides a vacuum mass flow control method, which may include the following steps:

[0099] Step S10: Receive the target vacuum flow rate value and compare the target vacuum flow rate value with the vacuum flow rate detected by the second sensor 50;

[0100] Step S12: When the difference between the target vacuum flow rate and the detected vacuum flow rate exceeds a preset difference, the control valve 80 is controlled to adjust its opening by combining the signal detected by the first sensor 94 and the current opening degree of the control valve 80.

[0101] Step S14: When the difference between the detected vacuum flow rate and the target vacuum flow rate is within a preset difference range, control the regulating valve 80 to stop adjusting the opening.

[0102] In this embodiment, the first sensor 94 can be used as a pressure sensor, the second sensor 50 as a mass flow sensor, and the control valve 80 as a piezoelectric proportional valve for example.

[0103] Specifically, controlling the opening adjustment of the control valve 80 by combining the signal detected by the first sensor 94 and the current opening degree of the control valve 80 includes: the controller 90 sending a PWM drive signal to the piezoelectric proportional valve; and adjusting the opening degree of the piezoelectric proportional valve by adjusting the duty cycle of the piezoelectric proportional valve.

[0104] In a specific scenario, the controller 90 can receive a target vacuum flow rate value sent by the client and compare the received target vacuum flow rate value with the current vacuum flow rate value detected by the mass flow sensor. If the difference between the target vacuum flow rate value and the detected vacuum flow rate exceeds a preset difference, it indicates that the current vacuum flow rate needs to be adjusted using the control valve 80. Specifically, during adjustment, a PWM signal can be sent to the piezoelectric proportional valve based on the current pressure sensor pressure and the current opening degree of the piezoelectric proportional valve, driving the valve to adjust its opening. The controller 90 can store the correspondence between the duty cycle and opening degree of the piezoelectric proportional valve. During adjustment, the opening degree of the piezoelectric proportional valve can be adjusted by changing its duty cycle, so that the current vacuum flow rate value approaches the target vacuum flow rate value, i.e., the difference between the detected vacuum flow rate and the target vacuum flow rate value is within a preset difference range.

[0105] The specific value of the preset difference is not specifically limited in this application. In theory, the closer the actual vacuum flow detected by the mass flow sensor is to the target vacuum flow value, the better. Ideally, the two can be completely consistent. However, due to different application environments, there are different requirements for control accuracy and control efficiency. The preset difference can be controlled within a certain range to meet the usage requirements.

[0106] All articles and references disclosed herein, including patent applications and publications, are incorporated herein by reference for various purposes. The term “substantially constitutes…” used to describe a combination should include the identified element, component, part, or step, as well as other elements, components, parts, or steps that do not substantially affect the essential novelty of the combination. The use of the terms “comprising” or “including” to describe combinations of elements, components, parts, or steps herein also contemplates embodiments substantially constituted by such elements, components, parts, or steps. The use of the term “may” herein is intended to indicate that any described attribute “may” include is optional. Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The disclosure of “a” or “an” used to describe an element, component, part, or step does not imply exclusion of other elements, components, parts, or steps.

[0107] The various embodiments described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from the others. Similar or identical parts between embodiments can be referred to interchangeably. The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made according to the spirit and essence of the present invention should be included within the scope of protection of the present invention.

Claims

1. A vacuum mass flow control device, characterized in that, include: Shell (10); The first flow channel (200) disposed in the housing (10) has a first starting end (21) and a first ending end (24), wherein the first starting end (21) is used to connect to a positive pressure gas source; The first sensor (94) is used to collect signals of the fluid in the first flow channel (200); The second flow channel (300) disposed within the housing (10) has a second starting end (31) and a second ending end, wherein the second starting end (31) is used to connect peripheral devices; The second sensor (50) is used to collect the vacuum flow rate in the second flow channel (300); The venturi tube (100) has an inlet end (110), an outlet end (120), and a negative pressure suction port (130); when the positive pressure fluid flowing out from the first termination end (24) flows through the venturi tube (100) through the inlet end (110), it will be drawn into the venturi tube (100) through the negative pressure suction port (130) along with the negative pressure fluid at the second termination end, and then flow out through the outlet end (120); A control valve (80) is used to adjust the flow cross-section of the first flow channel (200); The controller (90) is electrically connected to the control valve (80) and the first sensor (94) and the second sensor (50) to adjust the opening of the control valve (80) according to the feedback values ​​of the first sensor (94) and the second sensor (50), thereby realizing real-time control of the vacuum flow in the second flow channel; The first flow channel (200), the first sensor (94), the second flow channel (300), the second sensor (50), the venturi tube (100), the control valve (80), and the controller (90) are all integrated in the housing (10).

2. The vacuum mass flow control device as described in claim 1, characterized in that, The controller (90) can be used to: receive a target vacuum flow rate value and compare the target vacuum flow rate value with the vacuum flow rate detected by the second sensor (50). When the difference between the two exceeds a preset difference, the controller combines the signal detected by the first sensor (94) and the current opening degree of the control valve (80) to control the control valve (80) to adjust the opening degree until the difference between the detected vacuum flow rate and the target vacuum flow rate value is within the preset difference range.

3. The vacuum mass flow control device as described in claim 2, characterized in that, The first sensor (94) is a pressure sensor, the control valve (80) is a piezoelectric proportional valve, and the controller (90) controls the opening degree of the piezoelectric proportional valve by adjusting the duty cycle of the piezoelectric proportional valve.

4. The vacuum mass flow control device as described in any one of claims 1 to 3, characterized in that, The housing (10) is provided with a first connector (20), and the first connector (20) has a hollow cavity inside for forming the first flow channel (200). Along the fluid flow direction, the detection position of the first sensor (94) is located upstream of the control valve (80).

5. The vacuum mass flow control device as described in claim 4, characterized in that, The first connector (20) is provided with a branch channel (22) that communicates with the first flow channel (200). The open end of the branch channel (22) is connected to the first flow channel (200), and the other end is a closed end. The first sensor (94) is installed in the branch channel (22) in a sealed manner.

6. The vacuum mass flow control device as described in claim 4, characterized in that, The housing (10) is further provided with a second connector (70), which is used to connect the first connector (20) to the control valve (80).

7. The vacuum mass flow control device according to any one of claims 1 to 3, characterized in that, The housing (10) is further provided with a third connector (30), the third connector (30) having a hollow cavity inside for forming the second flow channel (300), and the second sensor (50) being disposed in the second flow channel (300).

8. The vacuum mass flow control device as described in any one of claims 1 to 3, characterized in that, The housing (10) is further provided with a fourth connector (60), the fourth connector (60) having a hollow main cavity (61) and a bypass cavity (62) connected to the main cavity (61). The main cavity (61) is connected to the first end (24) of the first flow channel (200) and is used to seal and install the Venturi tube (100). The bypass cavity (62) is connected to the second end of the second flow channel (300).

9. The vacuum mass flow control device as described in claim 8, characterized in that, The venturi tube (100) includes a first part (102) and a second part (103) sealed in the main cavity (61), with a confluence gap formed between the first part (102) and the second part (103); the confluence gap is disposed opposite to the bypass cavity (62).

10. The vacuum mass flow control device as described in claim 8, characterized in that, The flow cross-sectional area of ​​the first termination end (24) is smaller than the flow cross-sectional area of ​​the bypass cavity (62) and larger than the minimum flow cross-sectional area of ​​the venturi tube (100).

11. The vacuum mass flow control device according to any one of claims 1 to 3, characterized in that, The controller (90) includes a circuit board, which is disposed on the side of the housing (10) near the circuit board. A first DIP switch (92) and a second DIP switch (93) are also disposed on the side of the housing (10) near the circuit board, for switching different signal input and output modes.

12. A vacuum mass flow control method based on the vacuum mass flow control device according to claim 1, characterized in that, include: Receive the target vacuum flow rate value and compare the target vacuum flow rate value with the vacuum flow rate detected by the second sensor (50); When the difference between the target vacuum flow rate and the detected vacuum flow rate exceeds a preset difference, the control valve (80) is controlled to adjust its opening by combining the signal detected by the first sensor (94) and the current opening degree of the control valve (80). When the difference between the detected vacuum flow rate and the target vacuum flow rate is within a preset difference range, the control valve (80) is controlled to stop adjusting its opening.

13. The vacuum mass flow control method as described in claim 12, characterized in that, The first sensor (94) is a pressure sensor, and the control valve (80) is a piezoelectric proportional valve. The step of controlling the control valve (80) to adjust its opening by combining the signal detected by the first sensor (94) and the current opening degree of the control valve (80) includes: The controller (90) sends a PWM drive signal to the piezoelectric proportional valve; The opening degree of the piezoelectric proportional valve is controlled by adjusting the duty cycle of the piezoelectric proportional valve.

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