Gas pressure reducing valve and gas pressure reducing valve flow control method

Abstract

The application discloses a gas pressure reducing valve and a gas pressure reducing valve flow control method. The gas pressure reducing valve comprises a valve body, an inlet, a pressure regulating cavity and an outlet which are sequentially communicated and are used for gas circulation; a valve core assembly which divides the pressure regulating cavity into a high-pressure pressure regulating cavity and a low-pressure pressure regulating cavity, the high-pressure pressure regulating cavity is communicated with the inlet, the low-pressure pressure regulating cavity is communicated with the outlet, and the valve core assembly is used for adjusting the gas circulation opening degree between the high-pressure pressure regulating cavity and the low-pressure pressure regulating cavity; a nozzle which is connected to the outlet, the nozzle comprises an inlet section, a circulation section and an outlet section which are coaxially arranged along the gas flow direction, and the ratio between the length of the circulation section along the gas flow direction and the inner diameter of the circulation section is a preset proportional range when the nozzle is in a critical flow state; a detection assembly which comprises a low-pressure pressure detection element used for detecting the low-pressure pressure in the low-pressure pressure regulating cavity; and a controller which is electrically connected with the low-pressure pressure detection element, and the controller drives the valve core assembly to adjust the gas circulation opening degree according to the current pressure signal sent by the low-pressure pressure detection element.

Description

Technical Field

[0001] This application belongs to the field of pressure reducing valve technology, specifically relating to a gas pressure reducing valve and a gas pressure reducing valve flow control method. Background Technology

[0002] Gas pressure reducing valves are widely used in industrial gas supply systems, laboratory analytical instruments, semiconductor manufacturing equipment, and medical gas supply devices. Their core function is to reduce the high-pressure gas from the gas source to the working pressure required by downstream equipment and maintain a stable output of that pressure.

[0003] Currently, most common gas pressure reducing valves adopt a mechanical feedback structure. Their typical working principle is as follows: the target outlet pressure is set by adjusting the pre-compression of the spring; the actual outlet pressure is sensed by a diaphragm or piston; when the outlet pressure deviates from the set value, the diaphragm moves the valve core, changing the throttle opening, thereby achieving automatic pressure stabilization of the outlet.

[0004] However, traditional gas pressure reducing valves can only achieve stable pressure output, but cannot precisely control flow rate. In many applications requiring constant flow (such as carrier gas supply for gas analyzers and special gas delivery in semiconductor processes), users typically need to configure an additional mass flow controller (MFC) or float flow meter downstream of the pressure reducing valve to regulate and stabilize the flow rate. This approach has the following drawbacks: it requires the purchase and installation of two independent devices, increasing system hardware costs and installation space; the pipeline volume between the pressure reducing valve and the flow controller causes pressure transmission delay, affecting the dynamic response performance of flow control; and the measurement accuracy of traditional flow meters or mass flow controllers is easily affected by changes in downstream back pressure, making it difficult to maintain constant flow output under varying back pressure conditions. Summary of the Invention

[0005] The purpose of this application is to provide a gas pressure reducing valve and a gas pressure reducing valve flow control method to solve the problems of existing pressure reducing valves that can only stabilize pressure but cannot accurately control flow, as well as high cost, control lag, and flow rate affected by downstream pressure fluctuations.

[0006] To achieve the above objectives, this application provides a gas pressure reducing valve, comprising: The valve body has an air inlet, a pressure regulating chamber, and an air outlet that are connected in sequence and allow gas to flow through. A valve core assembly is located within the pressure regulating chamber and divides the pressure regulating chamber into a high-pressure regulating chamber and a low-pressure regulating chamber. The high-pressure regulating chamber is connected to the air inlet, and the low-pressure regulating chamber is connected to the air outlet. The valve core assembly is used to adjust the gas flow opening between the high-pressure regulating chamber and the low-pressure regulating chamber. A nozzle is connected to the air outlet. The nozzle includes an inlet section, a flow section, and an outlet section arranged coaxially along the airflow direction. The ratio between the length of the flow section along the airflow direction and the inner diameter of the flow section is a preset ratio range when the nozzle is in a critical flow state. The detection assembly includes a low-pressure detection element for detecting the low-pressure pressure within the low-pressure regulating chamber; The controller is electrically connected to the low-pressure detection element. The controller drives the valve core assembly to adjust the gas flow opening according to the current pressure signal sent by the low-pressure detection element until the current pressure reaches the target pressure. The target pressure is not lower than the minimum pressure value required to maintain the critical flow state.

[0007] In some embodiments, the flow section is provided with an inner diameter equal to that in the airflow direction, and the ratio of the length of the flow section along the airflow direction to the inner diameter of the flow section is in the range of 1:12 to 1:8.

[0008] In some embodiments, the nozzle further includes a converging section and an expanding section coaxially arranged, the converging section connecting the inlet section and the flow section, and the expanding section connecting the flow section and the outlet section. The converging section is used to smoothly accelerate the gas into the flow section, and the expanding section is used to restore the pressure of the gas in the portion of the flow section near the expanding section.

[0009] In some embodiments, the inner wall of the converging segment is an arc-shaped surface, and the angle between the inner tangent of the converging segment and the centerline of the converging segment gradually decreases from the inlet segment toward the outlet segment.

[0010] In some embodiments, the inner diameter of the expansion section gradually increases in the direction away from the flow section, the inlet section is provided with an inner diameter equal to that in the airflow direction, the outlet section is provided with an inner diameter equal to that in the airflow direction, the inner diameter of the inlet section is equal to the maximum inner diameter of the convergence section, and the inner diameter of the outlet end is equal to the maximum inner diameter of the expansion section.

[0011] In some embodiments, the gas pressure reducing valve further includes a diaphragm and an elastic element disposed within the valve body. The diaphragm covers the end of the low-pressure regulating chamber opposite to the high-pressure regulating chamber and contacts the valve core assembly. The first side of the diaphragm facing the low-pressure regulating chamber is used to sense the outlet pressure. The elastic element abuts against a second side of the diaphragm opposite to the low-pressure regulating chamber and is used to apply an elastic force to the diaphragm opposite to the outlet pressure. The diaphragm undergoes elastic deformation based on the pressure difference between the outlet pressure on the first side and the elastic force on the second side. This elastic deformation drives the valve core assembly to move to adjust the gas flow opening.

[0012] In some embodiments, the gas pressure reducing valve further includes an adjusting member that contacts the end of the elastic member opposite to the diaphragm, the elastic member being elastically compressed between the adjusting member and the diaphragm, and the adjusting member being movable in the height direction to press or release the elastic member.

[0013] In some embodiments, the valve core assembly includes an umbrella head and a valve core. The umbrella head is sealed to the inner peripheral wall of the pressure regulating chamber. The umbrella head has a gas flow channel. The high-pressure regulating chamber and the low-pressure regulating chamber are connected through the gas flow channel. The top of the valve core passes through the gas flow channel and contacts the diaphragm. The valve core is movable along the height direction to open or block the gas flow channel.

[0014] In some embodiments, the valve core includes a pin portion and a sealing portion connected in sequence. The pin portion extends through the gas flow channel, and the end of the pin portion away from the sealing portion abuts against the diaphragm. The cross-sectional area of ​​the end of the sealing portion increases in the direction away from the diaphragm, and the maximum outer diameter of the sealing portion is greater than the inner diameter of the gas flow channel.

[0015] In some embodiments, the valve core assembly further includes a shock-absorbing part, which is sleeved on one end of the valve core located in the high-pressure regulating chamber; the gas pressure reducing valve further includes a pressing boss, a limiting ring, and a digital display dial, the pressing boss being disposed between the elastic element and the diaphragm, the diaphragm being connected to the valve body through the limiting ring, and the digital display dial being disposed on the outside of the valve body, the digital display dial being two in number and displaying the pressure values ​​in the high-pressure regulating chamber and the low-pressure regulating chamber respectively.

[0016] A second aspect of this application provides a gas pressure reducing valve flow control method, employing the gas pressure reducing valve as described above, the gas pressure reducing valve flow control method comprising the following steps: The upstream pressure and temperature in the low-pressure regulating chamber and the downstream pressure at the nozzle outlet section are acquired in real time, and it is determined whether the nozzle is in a critical flow state according to the preset critical flow conditions. When the nozzle is in the critical flow state, a linear model is established between the mass flow rate through the nozzle and the upstream pressure, wherein the linear model has a linear scaling factor related to the upstream temperature and gas properties; Set a target flow rate, and calculate the target pressure in the low-pressure regulating chamber corresponding to the target flow rate based on the target flow rate and the linear model; By adjusting the regulating element of the gas pressure reducing valve, the actual pressure in the low-pressure regulating chamber is made to track the target pressure, thereby achieving linear control of the flow rate.

[0017] In some embodiments, the step of acquiring the upstream pressure and upstream temperature in the low-pressure regulating chamber and the downstream pressure at the nozzle outlet section in real time, and determining whether the nozzle is in a critical flow state according to a preset critical flow condition, includes: Substitute the upstream pressure, the upstream temperature, and the downstream pressure into the following formula to determine whether the critical flow condition is satisfactory;

[0018] in, The adiabatic index of the fluid. For the upstream pressure, The downstream pressure; If the above formula is satisfied, the nozzle enters the critical flow state; If the above formula is not met, the target pressure is adjusted according to the following formula, and the upstream pressure is increased so that the nozzle re-enters the critical flow state; in, The target pressure, The downstream pressure, This is the critical pressure ratio. This is to pre-set a safety margin.

[0019] In some implementations, the linear model between the mass flow rate and the upstream pressure is obtained by the following formula:

[0020] in, The mass flow rate, For the upstream pressure, the linear proportionality coefficient , This represents the radial cross-sectional area of ​​the nozzle's flow section. The gas constant is... The upstream temperature, The adiabatic index is the fluid's thermal index.

[0021] In some embodiments, the step of setting a target flow rate and calculating the target pressure in the low-pressure regulating chamber corresponding to the target flow rate based on the target flow rate and the linear model includes: Substitute the target flow rate into the following formula to calculate the required target pressure;

[0022] in, The target pressure, It is a linear scaling factor, and , For the set target traffic, This is the radial cross-sectional area of ​​the flow section of the nozzle. The gas constant is The upstream temperature, The adiabatic index of the fluid; The upstream temperature is acquired in real time, and the upstream temperature is substituted into the following formula to dynamically compensate the linear proportional coefficient.

[0023] in, For reference temperature, This is the nominal proportionality coefficient obtained through factory calibration at the reference temperature. The upstream temperature is mentioned.

[0024] In some embodiments, the control method further includes the step of: Compare the actual measured flow rate with the values ​​calculated by the linear model. The comparison is performed, and the proportional coefficient is corrected online using the following formula;

[0025] in, The scaling factor at the current moment. This is the scale factor updated in the next time step. The adaptive gain coefficient is 0 < <1, The actual measured flow rate The upstream pressure is mentioned above.

[0026] In some embodiments, the gas pressure reducing valve includes a controller, the controller including a fault diagnosis unit and a display unit, the fault diagnosis unit being configured to: When the upstream pressure in the low-pressure regulating chamber exceeds the target pressure and the deviation exceeds the first preset threshold, and the gas flow opening does not decrease as expected, it is determined that the nozzle is blocked, and the display unit is controlled to display the blockage alarm information. When the valve core assembly receives an instruction to close the gas flow channel, if the rate of decrease in upstream pressure exceeds a second preset threshold, it is determined to be an external leak, and the display unit is controlled to display a leak alarm message.

[0027] The above technical solution integrates pressure reduction and stabilization with the nozzle operating in a critical flow state, eliminating the need for an external, independent flow control device. This simplifies the system structure and reduces costs and installation space. Setting the target pressure to a minimum value required to maintain the critical flow state ensures the nozzle always operates in a critical flow state, providing the prerequisite for subsequent constant flow output. Real-time pressure feedback from a low-pressure sensor allows the controller to receive the current pressure signal, compare it with the target pressure, and drive the valve core assembly to dynamically adjust. This ensures the current pressure is precisely stabilized within the set target pressure range, achieving high-precision stability of the outlet pressure and indirectly controlling the mass flow rate through the nozzle.

[0028] Other features and advantages of the embodiments of this application will be described in detail in the following detailed description section. Attached Figure Description

[0029] The accompanying drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the following detailed description to explain the embodiments of this application, but do not constitute a limitation on the embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without any inventive effort. In the drawings: Figure 1 This is a schematic diagram of the gas pressure reducing valve of this application; Figure 2 This is a schematic diagram of the nozzle structure of the gas pressure reducing valve of this application; Figure 3 This is a schematic diagram of the gas pressure reducing valve of this application without the nozzle connected; Figure 4 for Figure 1 Enlarged diagram of point A in the middle.

[0030] Explanation of reference numerals in the attached figures 10. Valve body; 11. Air inlet; 12. Air outlet; 13. High-pressure regulating chamber; 14. Low-pressure regulating chamber; 20. Valve core assembly; 21. Umbrella head; 22. Valve core; 221. Pin part; 222. Sealing part; 23. Shock-absorbing part; 30. Nozzle; 31. Inlet section; 32. Flow section; 33. Outlet section; 34. Converging section; 35. Expanding section; 50. Diaphragm; 60. Elastic element; 70. Adjusting element; 80. Pressing boss; 90. Limiting ring. Detailed Implementation

[0031] The specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this application.

[0032] The following description, with reference to the accompanying drawings, describes a gas pressure reducing valve and a method for controlling the flow rate of the gas pressure reducing valve according to this application.

[0033] This application provides a gas pressure reducing valve, such as... Figures 1 to 2 As shown, the gas pressure reducing valve in this embodiment includes: The valve body 10 has an air inlet 11, a pressure regulating chamber and an air outlet 12 connected in sequence for gas flow. The inner wall of the valve body 10 is provided with a first silanized coating with a thickness of 200mm~500mm. The valve core assembly 20 is located in the pressure regulating chamber and divides the pressure regulating chamber into a high-pressure pressure regulating chamber 13 and a low-pressure pressure regulating chamber 14. The high-pressure pressure regulating chamber 13 is connected to the air inlet 11, and the low-pressure pressure regulating chamber 14 is connected to the air outlet 12. The valve core assembly 20 is used to adjust the gas flow opening between the high-pressure pressure regulating chamber 13 and the low-pressure pressure regulating chamber 14. The nozzle 30 is connected to the air outlet 12. The nozzle 30 includes an inlet section 31, a flow section 32 and an outlet section 33 arranged coaxially along the airflow direction. The ratio between the length of the flow section 32 along the airflow direction and the inner diameter of the flow section 32 is a preset ratio range when the nozzle 30 is in the critical flow state. The detection assembly (not shown) includes a low-pressure detection element (not shown) for detecting the low-pressure pressure inside the low-pressure regulating chamber 14. The controller is electrically connected to the low-pressure detection element. The controller drives the valve core assembly 20 to adjust the gas flow opening according to the current pressure signal sent by the low-pressure detection element until the current pressure reaches the target pressure. The target pressure is not lower than the minimum pressure value required to maintain the critical flow state.

[0034] In this embodiment, the pressure reduction and stabilization function is integrated with the nozzle 30, which is in a critical flow state. This eliminates the need for an external, independent flow control device, simplifying the system structure and reducing costs and installation space. The target pressure is set to be no less than the minimum pressure required to maintain the critical flow state. This control strategy ensures that the nozzle 30 always operates in a critical flow state, providing the prerequisite for subsequent constant flow output. A low-pressure sensor provides real-time pressure signal feedback. The controller receives the current pressure signal and compares it with the target pressure, driving the valve core assembly 20 to dynamically adjust. This ensures that the current pressure is precisely stabilized within the set target pressure range, achieving high-precision stability of the outlet pressure, thereby indirectly controlling the mass flow rate through the nozzle 30.

[0035] In this embodiment, the flow section 32 is set with a constant inner diameter in the airflow direction. Within this section, the cross-sectional area of ​​the flow channel remains constant (constant inner diameter) and does not continue to shrink. This inner diameter is the smallest flow inner diameter in the entire nozzle 30, which determines the critical flow rate when the gas reaches the speed of sound. The ratio of the length of the flow section 32 along the airflow direction to the inner diameter of the flow section 32 ranges from 1:12 to 1:8.

[0036] Specifically, this ratio range ensures that the gas achieves a stable sonic flow in the flow section 32, while avoiding frictional losses due to an excessively long flow section 32 and insufficient flow development due to an excessively short flow section 32. The constant inner diameter of the flow section 32 ensures uniform velocity distribution and good repeatability of the flow coefficient, thereby improving the accuracy of the constant flow output.

[0037] Of course, those skilled in the art can set the ratio of the length of the flow section 32 along the airflow direction to the inner diameter of the flow section 32 to 1:12, 1:11, 1:10, 1:9, 1:8, etc., according to the actual situation, and no single limitation is made here.

[0038] In this embodiment, various nozzle specifications 30 are designed for different flow rate application scenarios (0.1 sccm ~ 100 slm). The inner diameter of the flow section 32 is 0.1mm, 0.3mm, 0.8mm, 1.5mm, etc. By changing the effective cross-sectional area of ​​the flow section 32 of the nozzle 30 (or changing the pressure setting value of the low-pressure regulating chamber 14), different constant flow rates can be output within a wide range. The corresponding nozzle specification 30 can be selected according to the maximum operating flow rate. The nozzle 30 is installed at the air outlet 12 through the connector. Different specifications of nozzle 30 can be quickly replaced by unscrewing the connector without replacing the entire valve body 10.

[0039] In this embodiment, as Figure 2 As shown, the nozzle 30 also includes a converging section 34 and an expanding section 35 arranged coaxially. The converging section 34 is connected between the inlet section 31 and the flow section 32, and the expanding section 35 is connected between the flow section 32 and the outlet section 33. The converging section 34 is used to smoothly accelerate the gas to the flow section 32, and the expanding section 35 is used to restore the pressure of the gas in the part of the flow section 32 near the expanding section 35, thereby reducing the loss of kinetic energy at the outlet.

[0040] Specifically, the convergence section 34 smoothly accelerates the gas, avoiding eddies and separation; the expansion section 35 partially restores the gas pressure, reducing exhaust energy loss and improving energy utilization efficiency; the smooth acceleration and deceleration process reduces turbulence and shock waves, significantly reducing operating noise. The optimized profile allows the nozzle to maintain a stable critical flow state over a wider range of pressures and flow rates.

[0041] Furthermore, the convergence section 34 is an arc-shaped convergence section, with its internal wall being an arc-shaped surface. The angle between the internal tangent of the convergence section 34 and its centerline gradually decreases from the inlet section 31 towards the outlet section 33. Specifically, the arc-shaped surface allows the airflow to smoothly accelerate from subsonic to sonic speeds, avoiding flow separation and local eddies, and reducing irreversible pressure loss. The optimized convergence curve makes the critical pressure ratio closer to the theoretical value, reducing fluctuations caused by changes in inlet conditions.

[0042] Furthermore, the inner diameter of the expansion section 35 gradually increases in the direction away from the flow section 32. The inlet section 31 has an inner diameter equal to that in the airflow direction, and the outlet section 33 has an inner diameter equal to that in the airflow direction. The inner diameter of the inlet section 31 is equal to the maximum inner diameter of the converging section 34, and the inner diameter of the outlet end is equal to the maximum inner diameter of the expansion section 35. Specifically, the expansion section 35 diffuses pressure at a constant cone angle, achieving optimal pressure recovery efficiency while avoiding shock waves. The inner diameters of each section of the nozzle 30 are matched to avoid local pressure loss and flow disturbance caused by steps or abrupt changes.

[0043] In this embodiment, the nozzle 30 is installed at the air outlet 12 of the valve body 10. Its structure specifically includes an inner tube and an outer tube. The inner tube is nested within the inner wall of the outer tube and is secured and positioned at the air outlet 12 by the outer tube. The inner tube includes an inlet section 31, a converging section 34, a flowing section 32, an expanding section 35, and an outlet section 33, which are connected sequentially. The ratio of the length of the flowing section 32 along the airflow direction to its inner diameter is specifically selected as 1:10. The inner diameter of the flowing section 32 can be determined by the following formula:

[0044] in, For maximum mass flow rate, For flow coefficient, To stop the pressure, The gas constant is... For stagnation temperature, It represents the adiabatic index.

[0045] In this embodiment, the gas pressure reducing valve further includes a diaphragm 50 and an elastic element 60 disposed within the valve body 10. The diaphragm 50 covers the end of the low-pressure regulating chamber 14 away from the high-pressure regulating chamber 13 and contacts the valve core assembly 20. The first side of the diaphragm 50 facing the low-pressure regulating chamber 14 is used to sense the outlet pressure. The elastic element 60 abuts against the second side of the diaphragm 50 away from the low-pressure regulating chamber 14. The elastic element 60 is used to apply an elastic force to the diaphragm 50 opposite to the outlet pressure. The diaphragm 50 undergoes elastic deformation according to the pressure difference between the outlet pressure on the first side and the elastic force on the second side. The elastic deformation drives the valve core assembly 20 to move to adjust the gas flow opening.

[0046] Specifically, in this embodiment, no external power is required. Automatic pressure stabilization is achieved by balancing the pressure difference across the diaphragm 50 with the elastic force of the elastic element 60, resulting in high reliability. The deformation of the diaphragm 50 is directly transmitted to the valve core assembly 20 without intermediate transmission lag, ensuring rapid response to pressure changes. The diaphragm 50 simultaneously achieves pressure sensing, comparison, and actuation functions, reducing the number of components.

[0047] In the gas pressure reducing valve, the diaphragm 50 is the core sensing element, undertaking three key functions: pressure sensing, feedback, and execution. First, the diaphragm 50 directly contacts the gas in the low-pressure regulating chamber 14 (outlet), sensing pressure fluctuations in real time. Then, the diaphragm 50 compares the sensed pressure with the set force (elastic force) of the upper elastic element 60, and deforms due to the pressure difference between the two sides. The deformation drives the valve core assembly 20 to move, adjusting the gas flow opening. Through the closed-loop feedback mechanism of sensing-response-adjustment, the outlet pressure is stabilized at the set value without the need for external power.

[0048] It should be noted that the low-pressure regulating chamber 14 is connected to the air outlet 12, and the inlet section 31 of the nozzle 30 is connected to the air outlet 12. The aforementioned outlet pressure is the upstream pressure.

[0049] In this embodiment, the gas pressure reducing valve also includes an adjusting member 70, which contacts the end of the elastic member 60 away from the diaphragm 50. The elastic member 60 is elastically compressed between the adjusting member 70 and the diaphragm 50. The adjusting member 70 can move along the height direction to press or release the elastic member 60.

[0050] In this embodiment, the adjusting member 70 is specifically an adjusting nut. The adjusting nut has an external thread on its outer periphery, and the valve body 10 has an internal thread that engages with the external thread. The adjusting member 70 is threadedly connected to the open end of the valve body 10. The adjusting member 70 can be rotated clockwise or counterclockwise to move towards or away from the valve body 10. In this embodiment, the adjusting member 70 is screwed into the valve body 10, compressing the elastic member 60 that abuts against it. By rotating the adjusting member 70, the compression of the elastic member 60 can be changed; that is, the compression of the elastic member 60 increases when screwed into the valve body 10 and decreases when screwed out of the valve body 10, thereby setting the target value of the outlet pressure. At the same time, continuous and stepless adjustment of the outlet pressure can be achieved to adapt to different working conditions.

[0051] In this embodiment, the valve core assembly 20 includes an umbrella head 21 and a valve core 22. The umbrella head 21 is sealed to the inner peripheral wall of the pressure regulating chamber. The umbrella head 21 has a gas flow channel. The high pressure regulating chamber 13 and the low pressure regulating chamber 14 are connected through the gas flow channel. The top of the valve core 22 passes through the gas flow channel and contacts the diaphragm 50. The valve core 22 can move along the height direction to open or block the gas flow channel.

[0052] Specifically, the umbrella head 21 effectively isolates the high-pressure regulating chamber 13 and the low-pressure regulating chamber 14, preventing high-pressure gas from the high-pressure regulating chamber 13 from directly entering the low-pressure regulating chamber 14. The top of the valve core 22 passes through the gas flow channel opened on the umbrella head 21. This gas flow channel allows gas to flow while also guiding the valve core 22, ensuring that the valve core 22 maintains coaxiality when moving along the height direction, avoiding jamming or poor sealing caused by valve core misalignment. After passing through the gas flow channel, the top of the valve core 22 directly contacts the diaphragm 50. The deformation of the diaphragm 50 is directly transmitted to the valve core, eliminating intermediate transmission components, reducing gaps and friction in the force transmission path, and improving the sensitivity and response speed of the diaphragm 50's deformation to the valve core 22; at the same time, it reduces the risk of decreased control accuracy due to wear of transmission components.

[0053] In this embodiment, as Figure 3 and Figure 4 As shown, the valve core 22 includes a pin portion 221 and a sealing portion 222 connected in sequence. The pin portion 221 passes through the gas flow channel, and the end of the pin portion 221 away from the sealing portion 222 abuts against the diaphragm 50. The cross-sectional area of ​​the end of the sealing portion 222 increases in the direction away from the diaphragm 50, and the maximum outer diameter of the sealing portion 222 is greater than the inner diameter of the gas flow channel.

[0054] Specifically, the slender end of the ejector pin 221, furthest from the sealing part 222, directly abuts against the diaphragm 50. A slight elastic deformation of the diaphragm 50 drives the valve core to open, improving the valve core 22's response speed to changes in outlet pressure, reducing the driving force required for instantaneous opening, and allowing for greater design margins for the diaphragm 50 and elastic element 60, thus extending their service life. The end cross-sectional area of ​​the sealing part 222 increases in the direction away from the diaphragm 50 (i.e., it is conical or trumpet-shaped), with a maximum outer diameter larger than the inner diameter of the gas flow channel. When the valve core 22 moves upward (towards the low-pressure regulating chamber 14 from the high-pressure regulating chamber 13), the expanding surface of the sealing part 222 forms an annular line contact with the inlet edge of the gas flow channel. The high-pressure gas in the high-pressure regulating chamber 13 acts on the inclined surface of the sealing part 222, generating an upward additional clamping force. The higher the pressure, the tighter the seal. In the closed state, even if the upstream pressure fluctuates or increases, the sealing performance is enhanced, achieving pressure-assisted sealing and avoiding leakage problems caused by wear or impurity blockage in traditional planar seals. In the open state, the pin part 221 has minimal obstruction to the gas flow channel, and the sealing part 222 guides the gas smoothly into the gas flow channel and through, reducing gas resistance and impact on the valve core 22.

[0055] In this embodiment, the top of the valve core 22 passes through the gas flow channel. When the valve core 22 moves along the height direction, a variable throttling orifice is formed between its sealing part 222 and the inlet of the gas flow channel. The position and shape of the throttling orifice are jointly determined by the gas flow channel of the umbrella head 21 and the sealing part 222. The design parameters are clear and easy to optimize through simulation and experiment. There is a good linear relationship between the opening degree of the throttling orifice and the displacement of the valve core 22, which is beneficial to achieving precise flow regulation.

[0056] In this embodiment, the valve core assembly 20 further includes a shock-absorbing part 23, which is sleeved on one end of the valve core 22 located in the high-pressure regulating chamber 13; the gas pressure reducing valve also includes a pressing boss 80, a limiting ring 90 and a digital display dial (not shown in the figure), the pressing boss 80 is disposed between the elastic element 60 and the diaphragm 50, the diaphragm 50 is connected to the valve body 10 through the limiting ring 90, and the digital display dial is disposed on the outside of the valve body 10. There are two digital display dials, which respectively display the pressure values ​​in the high-pressure regulating chamber 13 and the low-pressure regulating chamber 14.

[0057] Specifically, the shock absorber 23 absorbs the impact energy during the opening and closing of the valve core 22, reducing valve core 22 vibration, lowering noise, and extending service life. Two digital display dials show the pressure in the high-pressure regulating chamber 13 and the low-pressure regulating chamber 14 respectively, facilitating real-time monitoring of the system status by the operator. The limit ring 90 fixes the position of the diaphragm 50 within the valve body 10, and the clamping boss 80 evenly transmits elastic force, improving the stability of the mechanical feedback.

[0058] A second aspect of this application provides a method for controlling the flow rate of a gas pressure reducing valve, using the gas pressure reducing valve as described above. The method includes the following steps: The upstream pressure and upstream temperature in the low-pressure regulating chamber 14 and the downstream pressure at the outlet section 33 of the nozzle 30 are acquired in real time, and it is determined whether the nozzle 30 is in a critical flow state according to the preset critical flow conditions. When the nozzle 30 is in the critical flow state, a linear model is established between the mass flow rate through the nozzle 30 and the upstream pressure, wherein the linear model has a linear scaling factor related to the upstream temperature and gas properties. Set the target flow rate, and calculate the target pressure in the low-pressure regulating chamber 14 corresponding to the target flow rate based on the target flow rate and the linear model; By adjusting the regulating element 70 of the gas pressure reducing valve, the actual pressure in the low-pressure regulating chamber 14 is made to track the target pressure, thereby achieving linear control of the flow rate.

[0059] In this embodiment, the gas pressure reducing valve flow control method includes determining the critical flow state, establishing a linear model, calculating the target pressure, and tracking and adjusting to linearize the nonlinear flow-pressure relationship. This method requires no complex nonlinear compensation algorithms, resulting in low computational cost. The linear model allows the control system to be considered a pure proportional or first-order system, reducing settling time by 30%–50%. The gain remains constant throughout the entire range, allowing conventional PID controllers to maintain consistent dynamic and static performance across the entire range. Utilizing the physical characteristics of the nozzle 30 in a critical flow state, combined with closed-loop feedback control, the accuracy reaches ±0.2% FS, far superior to the ±5%~±10% FS of traditional solutions. The signal path is shorter, and with optimized PID parameters (P=0.5, Ti=0.1s), the response time is ≤0.02 seconds, more than 100 times faster than traditional pressure reducing valves (>2 seconds).

[0060] In this embodiment, the steps of acquiring the upstream pressure and upstream temperature in the low-pressure regulating chamber 14 and the downstream pressure at the outlet section 33 of the nozzle 30 in real time, and determining whether the nozzle 30 is in a critical flow state according to the preset critical flow conditions, include: Substitute the upstream pressure, upstream temperature, and downstream pressure into the following formula to determine whether the critical flow condition is satisfactory;

[0061] in, The adiabatic index of the fluid. Due to upstream pressure, This is due to downstream pressure; If the above formula is satisfied, then nozzle 30 enters the critical flow state; If the above formula is not met, adjust the target pressure according to the following formula and increase the upstream pressure so that nozzle 30 re-enters the critical flow state; in, For target pressure, For downstream pressure, This is the critical pressure ratio. This is to pre-set a safety margin.

[0062] Critical flow condition requirements (Regarding air,) ,Right now If the current conditions are not met, it indicates that the target pressure value set upstream is too low. In this case, the target pressure should be increased. Reset to ( To set a safety margin, adjust the adjusting element 70 (screw it clockwise into the valve body 10) to increase the height. To the new target pressure value; once Once the nozzle is properly positioned, it re-enters the critical flow state, and the constant flow output resumes.

[0063] In this embodiment, by monitoring the critical flow condition in real time and actively adjusting the target pressure and increasing the upstream pressure when it is not met, the nozzle 30 re-enters the critical flow state, transforming from passive failure to active recovery. This ensures the continuity of constant flow output and avoids a sharp drop in flow control accuracy due to the loss of critical flow conditions. It not only determines the critical flow state but also actively adjusts when it deviates, ensuring that the nozzle 30 always operates in the optimal constant flow state. A preset safety margin is used... This helps to resist the interference of downstream pressure fluctuations on critical flow conditions. The controller can directly base its operation on the current downstream pressure detected by the pressure sensor and the known... (Based on the gas adiabatic index) The system calculates the required target pressure and maintains a consistent recovery strategy under different operating conditions and at different times, thus avoiding the uncertainty of human operation.

[0064] In this embodiment, the linear model between mass flow rate and upstream pressure is obtained through the following formula:

[0065] in, For quality flow, For upstream pressure, linear proportionality coefficient , The radial cross-sectional area of ​​the flow section 32 of the nozzle 30 is given. The gas constant is For upstream temperature, The adiabatic index of the fluid.

[0066] In this embodiment, no nonlinear compensation is required, and a conventional PID controller can achieve high-precision control, reducing the controller's computational burden by more than 50%. By eliminating nonlinear iterative calculations, the control cycle can be shortened by 30% to 50%, achieving high-bandwidth flow response. Within the linear range, the system's open-loop gain does not change with the operating point, avoiding the drawbacks of slow response in the low-flow range and easy overshoot in the high-flow range in traditional methods.

[0067] In this embodiment, the steps of setting a target flow rate and calculating the target pressure in the low-pressure regulating chamber 14 corresponding to the target flow rate based on the target flow rate and the linear model include: Substitute the target flow rate into the following formula to calculate the required target pressure;

[0068] in, For target pressure, It is a linear scaling factor, and , For the set target traffic, The radial cross-sectional area of ​​the flow section 32 of the nozzle 30 is given. The gas constant is The upstream temperature, The adiabatic index of the fluid; The upstream temperature is acquired in real time, and the upstream temperature is substituted into the following formula to dynamically compensate the linear proportional coefficient.

[0069] in, For reference temperature, This is the nominal proportionality coefficient obtained through factory calibration at the reference temperature. This refers to the upstream temperature.

[0070] In this embodiment, the upstream temperature is collected in real time. and according to the formula Dynamic correction ratio coefficient This allows the calculation of the target pressure to be performed using... The value always reflects the true physical characteristics at the current temperature, thus eliminating the interference of temperature fluctuations on flow control accuracy. It only requires a single calibration at a single reference temperature. This eliminates the need for repeated calibration at different temperatures, significantly reducing the time and cost of factory calibration while ensuring the theoretical optimality of compensation accuracy.

[0071] In this embodiment, the control method further includes the following steps: Compare the actual measured flow rate with the values ​​calculated by the linear model. The comparison is performed, and the scaling factor is corrected online using the following formula (recursive least squares gradient descent method);

[0072] in, The scaling factor at the current moment. This is the scale factor updated in the next time step. The adaptive gain coefficient is 0 < <1, The actual measured flow rate This is due to upstream pressure.

[0073] In this embodiment, the linear scaling factor is corrected online using the recursive least squares gradient descent method. It can automatically compensate for nonlinear deviations caused by factors such as minor wear of the nozzle throat due to long-term use, gas density changes in the low-pressure regulating chamber 14, and airflow pulsation, enabling the system to maintain high-precision constant flow control throughout its entire lifespan and significantly extending the calibration cycle. It employs a small gain coefficient. (0 < <1) Gradual update The system avoids flow rate jumps caused by sudden parameter changes, ensuring stable and reliable system operation. Simultaneously, the aforementioned temperature compensation quickly eliminates the main deviations caused by temperature variations, while the adaptive correction in this embodiment finely compensates for the remaining residual deviations. These two mechanisms work together to achieve optimal constant flow control accuracy across the entire operating range.

[0074] In this embodiment, the gas pressure reducing valve includes a controller, which is configured to: Based on the preset target flow rate and the critical flow characteristics of nozzle 30, calculate the target pressure required to maintain the critical flow state. The target pressure shall not be lower than the minimum pressure required to maintain the critical flow state. The system receives the current pressure signal sent by the low-pressure detection element and drives the valve core assembly 20 to adjust the gas flow opening so that the current pressure (upstream pressure) reaches the target pressure, thereby making the nozzle 30 always work in the critical flow state and output a constant flow rate that is linearly related to the current pressure.

[0075] Furthermore, the controller includes a fault diagnosis unit and a display unit, wherein the fault diagnosis unit is configured as follows: When the upstream pressure in the low-pressure regulating chamber 14 exceeds the target pressure and the deviation exceeds the first preset threshold, and the gas flow opening does not decrease as expected, it is determined that the nozzle 30 is blocked, and the control display unit displays the blockage alarm information. When the valve core 22 receives the instruction to close the gas flow channel, if the rate of decrease in upstream pressure exceeds the second preset threshold, it is determined to be an external leak, and the display unit is controlled to display the leak alarm information.

[0076] In this embodiment, the built-in fault self-diagnosis program significantly improves the intelligence and reliability of the gas pressure reducing valve. Regarding nozzle 30 blockage diagnosis, the diagnostic logic employs a triple-condition judgment method where high pressure, deviation exceeding the threshold, and opening not decreasing simultaneously are met. This effectively distinguishes between genuine blockage faults and normal PID regulation overshoot or gas source fluctuations, avoiding frequent false alarms. Once blockage is detected, a clear alarm message is immediately output through the display unit, allowing operators to quickly locate the fault, shorten downtime, and prevent abnormal upstream pressure increases from damaging the diaphragm and seals, ensuring equipment and process safety. For external leak diagnosis, the system automatically enters leak detection mode after the valve core 22 closes, using existing pressure sensors to monitor the pressure drop rate, eliminating the need for additional dedicated leak detection equipment. By setting a second preset threshold, the degree of leakage can be quantified, and graded alarms can be further implemented. This diagnosis can distinguish between internal and external leaks, helping maintenance personnel quickly pinpoint the leak location and reduce the scope of investigation. For expensive or toxic gases, timely leak detection can significantly reduce economic losses and safety hazards.

[0077] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0078] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0079] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0080] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A gas pressure reducing valve, characterized in that, include: The valve body (10) has an air inlet (11), a pressure regulating chamber and an air outlet (12) connected in sequence for gas flow. The valve core assembly (20) is located in the pressure regulating chamber and divides the pressure regulating chamber into a high-pressure pressure regulating chamber (13) and a low-pressure pressure regulating chamber (14). The high-pressure pressure regulating chamber (13) is connected to the air inlet (11), and the low-pressure pressure regulating chamber (14) is connected to the air outlet (12). The valve core assembly (20) is used to adjust the gas flow opening between the high-pressure pressure regulating chamber (13) and the low-pressure pressure regulating chamber (14). The nozzle (30) is connected to the air outlet (12). The nozzle (30) includes an inlet section (31), a flow section (32) and an outlet section (33) arranged coaxially along the airflow direction. The ratio between the length of the flow section (32) along the airflow direction and the inner diameter of the flow section (32) is a preset ratio range when the nozzle (30) is in the critical flow state. The detection assembly includes a low-pressure detection element for detecting the low-pressure regulating chamber (14); The controller is electrically connected to the low-pressure detection element. The controller drives the valve core assembly (20) to adjust the gas flow opening according to the current pressure signal sent by the low-pressure detection element until the current pressure reaches the target pressure. The target pressure is not lower than the minimum pressure value required to maintain the critical flow state.

2. The gas pressure reducing valve according to claim 1, characterized in that, The flow section (32) is provided with an inner diameter equal to that in the airflow direction, and the ratio of the length of the flow section (32) along the airflow direction to the inner diameter of the flow section (32) is in the range of 1:12 to 1:

8.

3. The gas pressure reducing valve according to claim 1, characterized in that, The nozzle (30) further includes a converging section (34) and an expanding section (35) arranged coaxially. The converging section (34) is connected between the inlet section (31) and the flow section (32), and the expanding section (35) is connected between the flow section (32) and the outlet section (33). The converging section (34) is used to smoothly accelerate the gas to the flow section (32), and the expanding section (35) is used to restore the pressure of the gas in the part of the flow section (32) near the expanding section (35).

4. The gas pressure reducing valve according to claim 3, characterized in that, The inner wall of the converging segment (34) is an arc-shaped surface, and the angle between the inner tangent of the converging segment (34) and the center line of the converging segment (34) gradually decreases from the entrance segment (31) toward the exit segment (33).

5. The gas pressure reducing valve according to claim 3, characterized in that, The inner diameter of the expansion section (35) gradually increases in the direction away from the flow section (32). The inlet section (31) is set with an inner diameter equal to that in the airflow direction. The outlet section (33) is set with an inner diameter equal to that in the airflow direction. The inner diameter of the inlet section (31) is equal to the maximum inner diameter of the convergence section (34). The inner diameter of the outlet end is equal to the maximum inner diameter of the expansion section (35).

6. The gas pressure reducing valve according to claim 1, characterized in that, The gas pressure reducing valve also includes a diaphragm (50) and an elastic element (60) disposed within the valve body (10). The diaphragm (50) covers the end of the low-pressure regulating chamber (14) away from the high-pressure regulating chamber (13) and contacts the valve core assembly (20). The first side of the diaphragm (50) facing the low-pressure regulating chamber (14) is used to sense the outlet pressure. The elastic element (60) abuts against the second side of the diaphragm (50) away from the low-pressure regulating chamber (14). The elastic element (60) is used to apply an elastic force opposite to the outlet pressure to the diaphragm (50). The diaphragm (50) undergoes elastic deformation according to the pressure difference between the outlet pressure on the first side and the elastic force on the second side. The elastic deformation drives the valve core assembly (20) to move to adjust the gas flow opening.

7. The gas pressure reducing valve according to claim 6, characterized in that, The gas pressure reducing valve also includes an adjusting member (70), which contacts the end of the elastic member (60) away from the diaphragm (50). The elastic member (60) is elastically compressed between the adjusting member (70) and the diaphragm (50). The adjusting member (70) can move along the height direction to press or release the elastic member (60).

8. The gas pressure reducing valve according to claim 7, characterized in that, The valve core assembly (20) includes an umbrella head (21) and a valve core (22). The umbrella head (21) is sealed to the inner peripheral wall of the pressure regulating chamber. The umbrella head (21) has a gas flow channel. The high pressure regulating chamber (13) and the low pressure regulating chamber (14) are connected through the gas flow channel. The top of the valve core (22) passes through the gas flow channel and contacts the diaphragm (50). The valve core (22) can move along the height direction to open or block the gas flow channel.

9. The gas pressure reducing valve according to claim 8, characterized in that, The valve core (22) includes a pin portion (221) and a sealing portion (222) connected in sequence. The pin portion (221) passes through the gas flow channel, and the end of the pin portion (221) away from the sealing portion (222) abuts against the diaphragm (50). The cross-sectional area of ​​the end of the sealing portion (222) increases in the direction away from the diaphragm (50), and the maximum outer diameter of the sealing portion (222) is greater than the inner diameter of the gas flow channel.

10. The gas pressure reducing valve according to claim 8, characterized in that, The valve core assembly (20) further includes a shock-absorbing part (23), which is sleeved on the valve core (22) at one end of the high-pressure regulating chamber (13); the gas pressure reducing valve further includes a pressing boss (80), a limiting ring (90) and a digital display dial, the pressing boss (80) is disposed between the elastic element (60) and the diaphragm (50), the diaphragm (50) is connected to the valve body (10) through the limiting ring (90), the digital display dial is disposed on the outside of the valve body (10), and there are two digital display dials that respectively display the pressure values ​​in the high-pressure regulating chamber (13) and the low-pressure regulating chamber (14).

11. A method for controlling the flow rate of a gas pressure reducing valve, characterized in that, The gas pressure reducing valve as described in any one of claims 1 to 10 is used, and the flow control method of the gas pressure reducing valve includes the following steps: The upstream pressure and upstream temperature in the low-pressure regulating chamber (14) and the downstream pressure at the outlet section (33) of the nozzle (30) are obtained in real time, and the nozzle (30) is judged to be in a critical flow state according to the preset critical flow conditions. When the nozzle (30) is in the critical flow state, a linear model is established between the mass flow rate through the nozzle (30) and the upstream pressure, wherein the linear model has a linear scaling factor related to the upstream temperature and gas properties; Set a target flow rate, and calculate the target pressure in the low-pressure regulating chamber (14) corresponding to the target flow rate based on the target flow rate and the linear model; By adjusting the regulating element (70) of the gas pressure reducing valve, the actual pressure in the low-pressure regulating chamber (14) tracks the target pressure, thereby achieving linear control of the flow rate.

12. The gas pressure reducing valve flow control method according to claim 11, characterized in that, The step of acquiring the upstream pressure and upstream temperature in the low-pressure regulating chamber (14) and the downstream pressure at the outlet section (33) of the nozzle (30) in real time, and determining whether the nozzle (30) is in a critical flow state according to the preset critical flow conditions includes: Substitute the upstream pressure, the upstream temperature, and the downstream pressure into the following formula to determine whether the critical flow condition is satisfactory; in, The adiabatic index of the fluid. For the upstream pressure, The downstream pressure; If the above formula is satisfied, the nozzle (30) enters the critical flow state; If the above formula is not met, the target pressure is adjusted according to the following formula, and the upstream pressure is increased so that the nozzle (30) re-enters the critical flow state; in, The target pressure, The downstream pressure, This is the critical pressure ratio. This is to pre-set a safety margin.

13. The gas pressure reducing valve flow control method according to claim 11, characterized in that, The linear model between the mass flow rate and the upstream pressure is obtained through the following formula: in, The mass flow rate, For the upstream pressure, the linear proportionality coefficient , The radial cross-sectional area of ​​the flow section (32) of the nozzle (30) is given. The gas constant is The upstream temperature, The adiabatic index of the fluid.

14. The gas pressure reducing valve flow control method according to claim 11, characterized in that, The step of setting a target flow rate and calculating the target pressure in the low-pressure regulating chamber (14) corresponding to the target flow rate based on the target flow rate and the linear model includes: Substitute the target flow rate into the following formula to calculate the required target pressure; in, The target pressure, It is a linear scaling factor, and , For the set target traffic, The radial cross-sectional area of ​​the flow section (32) of the nozzle (30) is given. The gas constant is... The upstream temperature, The adiabatic index of the fluid; The upstream temperature is acquired in real time, and the upstream temperature is substituted into the following formula to dynamically compensate the linear proportional coefficient. in, For reference temperature, This is the nominal proportionality coefficient obtained through factory calibration at the reference temperature. The upstream temperature is mentioned.

15. The gas pressure reducing valve flow control method according to claim 11, characterized in that, The control method further includes the following steps: Compare the actual measured flow rate with the values ​​calculated by the linear model. The comparison is performed, and the proportional coefficient is corrected online using the following formula; in, The scaling factor at the current moment. This is the scale factor updated in the next time step. The adaptive gain coefficient is 0 < <1, The actual measured flow rate The upstream pressure is mentioned above.

16. The gas pressure reducing valve flow control method according to claim 11, characterized in that, The gas pressure reducing valve includes a controller, which includes a fault diagnosis unit and a display unit. The fault diagnosis unit is configured to: When the upstream pressure in the low-pressure regulating chamber (14) exceeds the target pressure and the deviation exceeds the first preset threshold, and the gas flow opening does not decrease as expected, it is determined that the nozzle (30) is blocked, and the display unit is controlled to display the blockage alarm information. When the valve core (22) of the valve core assembly (20) is instructed to close the gas flow channel, if the rate of decrease of the upstream pressure exceeds the second preset threshold, it is determined to be an external leak, and the display unit is controlled to display the leak alarm information.

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