A small flow anti-surge valve core structure of a pressure regulator and a method for calculating its size

Abstract

The present invention provides a small flow anti-surge valve core structure for a pressure regulator, which belongs to the technical field of gas pressure regulating equipment in a gas transmission and distribution system. The small flow anti-surge valve core structure for a pressure regulator includes a valve body, a gas flow channel formed by a valve port or a valve seat arranged in the valve body, and a valve core arranged in the valve body and movably plugged into the flow channel; the flow channel is a vertical through hole with a consistent inner diameter, the valve core is in the shape of an inverted frustum, and the diameter of the top surface of the inverted frustum matches the inner diameter of the flow channel; the small flow anti-surge valve core structure for a pressure regulator of the present invention designs the valve core in the shape of an inverted frustum, so that the actual opening of the pressure regulator at a small flow rate is greater than the original required opening, so that the pressure regulator avoids the most unstable position and prevents frequent surges in the small flow range. The present invention also provides a method for calculating the size of a small flow anti-surge valve for a pressure regulator. The final calculation formula obtained by this method is simple, and the valve core shape and size suitable for the pressure regulator can be quickly and accurately calculated, which can greatly save the time for valve core size design.

Description

Technical Field

[0001] The present invention relates to the technical field of gas pressure regulating equipment in a gas transmission and distribution system, and in particular to a small-flow anti-surge valve core structure of a pressure regulator and a method for calculating its size. Background Art

[0002] The gas pressure regulator is a pneumatic component combination device driven by a diaphragm + spring. It controls the valve opening by sensing the pressure of the elastic diaphragm and achieving a balance with the spring loading force. The key performance indicators of the pressure regulator include: regulation accuracy, closing pressure level, flow coefficient, etc. The test results of the key performance indicators determine the effective application range of the pressure regulator, including the accuracy range of the regulation pressure, the accuracy level of the closing pressure, and the effective flow range within the regulation pressure accuracy range. This series of change relationships can be described by the static characteristic curve of the pressure regulator, as shown in the attached figure. Figure 1 shown.

[0003] It can be seen from the schematic diagram of the static characteristic curve of the voltage regulator that the curve drawn under different flow rates corresponding to the back pressure P2 of the voltage regulator is the static characteristic curve. P2 has been showing a downward trend as the flow rate gradually increases, and the curve has an intersection with the upper and lower deviation limits of the voltage regulator accuracy range. The intersection with the upper deviation corresponds to Qmin, that is, the minimum effective flow within the accuracy range of the voltage regulator; the intersection with the lower deviation corresponds to Qmax, that is, the maximum effective flow within the accuracy range of the voltage regulator.

[0004] The interval where the flow rate is less than Qmin is the small flow interval of the voltage regulator. During actual operation, when the voltage regulator is working in this small flow interval, there is a high probability that the voltage regulator will frequently surge.

[0005] Frequent surges in the voltage regulator can cause the following problems:

[0006] 1. The back pressure P2 fluctuates up and down, and the fluctuation caused by surge will cause the upper and lower deviation values ​​to exceed the accuracy range, thereby affecting the real-time pressure control performance of the pressure regulator. When the fluctuation range exceeds the downstream gas usage range, it will cause serious operation failures;

[0007] 2. Surge is a high-frequency vibration, which will accelerate the wear of the internal components of the voltage regulator and shorten the life of the moving parts;

[0008] 3. When surge occurs, the regulator valve port and the valve port gasket are in frequent and rapid small-amplitude open-close-open-close reciprocating motion, which accelerates the wear of the valve port gasket sealing material and shortens the life of the seal;

[0009] 4. Surge will also bring about intense ups and downs in the sound, which will cause serious interference to on-site practitioners and residents outside the operation area;

[0010] 5. Surge will also cause vibration of the voltage regulator and the connected pipes before and after. The surge of the voltage regulator cannot be effectively prevented for a long time. Once resonance occurs, there is a risk of pipeline weld fracture;

[0011] 6. Pressure fluctuations caused by surge will cause frequent measurement fluctuations in the measuring instrument, resulting in inaccurate measurement.

[0012] The existing technology for dealing with the surge problem of the voltage regulator includes:

[0013] 1) Add a throttle valve after the pressure regulator and stop panting by reducing the throttle valve opening.

[0014] Disadvantages: It increases equipment cost and floor space, and has poor flow adaptability. Once the flow range changes, the throttle valve opening must be readjusted, and operability is poor.

[0015] 2) Install a damper on the pressure feedback signal tube after the voltage regulator to alleviate surge by damping and filtering the feedback signal.

[0016] Disadvantages: The damper of the feedback signal needs to be debugged on site, and the debugging time is long and the debugging is difficult; the flow adaptability is poor, and once the flow range changes, it must be re-debugged; after the damper filters the feedback signal, it will actually attenuate the air pressure value of the feedback signal, increase signal distortion, and thus cause other safety hazards.

[0017] 3) Modify the internal structure of the voltage regulator to reduce the flow coefficient Cg value of the voltage regulator so that the voltage regulator can adapt to the small flow condition again.

[0018] Disadvantages: The feasibility of modifying the pressure regulators manufactured by different manufacturers varies, and the applicability cannot be guaranteed. In addition, the modification cost is high and the cycle is long. When the actual gas consumption increases, the modified pressure regulator may not be able to adapt to the new working conditions.

[0019] 4) Modify the pipeline and temporarily replace it with a smaller-diameter pressure regulator to match the current operating conditions.

[0020] Disadvantages: The cost of pipeline reconstruction is high, the construction period is long, and it is necessary to purchase additional small pressure regulators. At the same time, when the actual gas consumption increases, the modified pressure regulator may not be able to adapt to the new working conditions. Summary of the invention

[0021] The present invention aims to design a small flow anti-surge valve core structure for the pressure regulator based on the characteristics of the static characteristics of the pressure regulator, so as to achieve the effect of not changing the original main structure of the pressure regulator, but preventing the pressure regulator from frequent surge in the small flow range, and at the same time not affecting the supply of large flow, and being simple and convenient to use.

[0022] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0023] A small flow anti-surge valve core structure of a pressure regulator comprises a valve body, a gas flow channel formed by a valve port or a valve seat arranged in the valve body, and a valve core arranged in the valve body and movably connected to the flow channel; the flow channel is a vertical cylindrical through hole with a consistent inner diameter, the valve core is in the shape of an inverted frustum, and the diameter of the top surface of the inverted frustum matches the inner diameter of the flow channel.

[0024] Optionally, the bottom surface of the inverted cone is also provided with a secondary inverted cone, the top surface area of ​​the secondary inverted cone is not larger than the bottom surface area of ​​the inverted cone, and the center of the top surface of the secondary inverted cone coincides with the center of the bottom surface of the inverted cone; the angle between the inclined surface of the secondary inverted cone and its top surface is smaller than the angle between the inclined surface of the inverted cone and its top surface.

[0025] Optionally, the top surface of the secondary inverted circular frustum completely overlaps with the bottom surface of the inverted circular frustum.

[0026] Optionally, there are multiple sub-inverted cones, and the tops and bottoms of the multiple sub-inverted cones are connected, and the top surface of the sub-inverted cone located below completely overlaps with the bottom surface of the sub-inverted cone located above; the angle between the inclined surface of the sub-inverted cone located below and its top surface is smaller than the angle between the inclined surface of the sub-inverted cone located above and its top surface.

[0027] Optionally, the angle between the inclined surface of the inverted frustum and its top surface is 75°, and the angle between the inclined surface of the secondary inverted frustum connected to the bottom surface of the inverted frustum and its top surface is 55°.

[0028] Optionally, the difference between the angle between the inclined surface of the secondary inverted circular frustum located at the bottom and its top surface and the angle between the inclined surface of the secondary inverted circular frustum located at the top and its top surface is 5° to 65°.

[0029] Optionally, the edges of the connecting surfaces between the inverted frustum and the secondary inverted frustum, and the edges of the connecting surfaces between the secondary inverted frustum located above and the secondary inverted frustum located below, are rounded, that is, the side surface of the valve core is a smooth curved surface.

[0030] Optionally, the inverted frustum and the secondary inverted frustum are manufactured by integral molding.

[0031] Based on the same inventive concept, the present invention also provides a method for calculating the structural dimensions of a small flow anti-surge valve core of a pressure regulator.

[0032] Step 1, measuring the critical flow rate q of surge of the voltage regulator;

[0033] The surge of the pressure regulator occurs because the excessive flow capacity of the pressure regulator cannot adapt to the actual small flow demand, causing the reciprocating switch of the valve internals to cause violent fluctuations. To solve the surge at small flow from the inside, it is necessary to make the pressure regulator avoid the original small opening range through structural design, that is, to make the actual opening of the pressure regulator at small flow greater than the original required opening, so that the pressure regulator completely avoids the most unstable position; and the flow rate when the pressure regulator is in the most unstable state is the critical flow rate that causes the pressure regulator to surge, so the critical flow rate of the pressure regulator surge should be measured first to obtain the environmental conditions.

[0034] Step 2, calculating the throttling stroke h of the pressure regulator according to the ideal gas state equation and the critical flow rate q of the pressure regulator surge;

[0035] To make the initial opening of the pressure regulator larger than the original design value, the principle of throttling needs to be used. By effectively throttling the flow area at the unstable opening position, the flow volume at that position is extremely small. In order to meet the downstream demand, the pressure regulator has to obtain a larger opening. In order to achieve the throttling effect of small flow inside the pressure regulator, the throttling stroke must be confirmed.

[0036] According to the ideal gas state equation:

[0037] PV=nRT

[0038] in,

[0039] P——Air pressure (absolute pressure)

[0040] V——Volume

[0041] n——molar amount of the substance

[0042] R——Universal gas constant (i.e., constants are equal under the same gas quality)

[0043] T——Thermodynamic temperature (Kelvin temperature, 1 thermodynamic temperature is: 273℃)

[0044] Under the premise that the working pressure and temperature of the voltage regulator remain unchanged, P, R, and T in the formula are all constants, so it can be seen that the variables V and n are in direct proportion.

[0045] Considering V as the flow space of the gas flow channel of the pressure regulator, and n as the molar amount of gas that can pass through the gas flow channel of the pressure regulator, the flow volume of the gas flow channel of the pressure regulator is proportional to the amount of gas that can pass through.

[0046] The gas flow channel of the pressure regulator is cylindrical. According to the formula of cylinder volume = bottom area x height, the volume is proportional to the gas volume. Under the premise that the bottom area remains unchanged, the valve opening is also proportional to the gas volume, which conforms to the ratio of the linear flow characteristic.

[0047] Then the critical opening value formula of the voltage regulator surge can be obtained:

[0048]

[0049] In the formula,

[0050] h——critical opening value of voltage regulator surge, also the throttling stroke value, unit: mm;

[0051] H——maximum design opening of the voltage regulator, unit: mm;

[0052] q——critical flow rate of surge of voltage regulator, unit: Nm 3 / h;

[0053] Q——Flow rate corresponding to the maximum design opening of the pressure regulator, unit: Nm 3 / h;

[0054] It can be seen from this that the ratio of the critical opening value of the voltage regulator surge to the maximum design opening of the voltage regulator is equal to the ratio of the rectified gas volume to the total gas volume of the gas flow channel; wherein, the critical opening value of the voltage regulator surge is the throttling stroke value, and the throttling stroke h of the voltage regulator is greater than 0 and less than 1 / 2 of the maximum design opening H of the voltage regulator.

[0055] Step 3, calculating the throttling area according to the throttling stroke h;

[0056] The throttle area determines the amount of gas that can pass through the throttle stroke.

[0057] It can be seen from the structural design of the small flow anti-surge valve core of the pressure regulator that in order to make the pressure regulator still have good applicability and stability in the throttling state, before the opening of the pressure regulator enters the normal range, the structural design of the valve core makes it form a throttling range in the gas flow channel, and the throttling range includes a rectifying range formed by an inverted circular cone and an involute range formed by a secondary inverted circular cone;

[0058] Rectification interval: It covers the entire interval of the critical surge opening of the voltage regulator, so its span distance is not less than the throttling stroke h. In practical applications, the span of the rectification area can be designed to be 1-2.5 times the value of h according to the current limiting characteristics of the voltage regulator design.

[0059] Involute interval: After the opening of the voltage regulator gradually exceeds the rectification interval, the gas passing area should be gradually increased to obtain a gradually increasing gas passing volume. The involute interval allows the voltage regulator to gradually obtain flow gain through the involute curve structure.

[0060] Normal range: The normal air supply range after the voltage regulator opening leaves the rectification range and the gradual opening range.

[0061] (1) Calculate the bottom cross-sectional area S1 of the rectifier section

[0062] The gas flow area of ​​the rectifier section is to adapt to the small flow condition by throttling. Therefore, the gas flow area of ​​this section should be designed as a percentage of the surge critical flow of the regulator (or less than the surge critical flow, which can be determined according to the throttling control requirements), that is, the ratio of the bottom cross-sectional gas flow area of ​​the rectifier section to the total area of ​​the gas flow channel, which is equal to the ratio of the rectifier gas flow volume to the total gas flow volume of the gas flow channel:

[0063]

[0064] Therefore, we can get:

[0065]

[0066] In the formula,

[0067] S1——the bottom cross-sectional gas area of ​​the rectifier section, which is a variable, unit: mm 2 ;

[0068] S——Gas flow area of ​​the inner diameter of the gas flow channel, quantitative, unit: mm 2 ;

[0069] in,

[0070]

[0071] In the formula,

[0072] D——Inner diameter of gas flow channel, quantitative, unit: mm;

[0073] Therefore, we can get:

[0074]

[0075] Substituting into formula 1, we get:

[0076]

[0077] (2) Based on the bottom cross-sectional gas flow area S1 of the rectifying interval and the gas supply variation coefficient q, calculate the bottom cross-sectional gas flow area S2 of the involute interval

[0078] The gradually opening interval is the transition section between the rectification interval and the normal interval. The air supply volume and the air supply volume change value in this interval should be greater than the rectification interval and less than the normal interval.

[0079] In order to maintain the linear characteristics, the corresponding coefficient is multiplied in the rectification interval calculation formula, that is:

[0080] S2=α×S1……Formula 3

[0081] Where:

[0082] S2——the bottom cross-section gas area of ​​the gradually opening interval, which is a variable, unit: mm 2

[0083] α is the ratio coefficient of the gas flow area in the involute interval to the gas flow area in the rectifier interval.

[0084] The α value is determined according to the gas supply volume of the pressure regulator, and is usually between 5 and 10.

[0085] When the aforementioned anti-surge valve core structure of the pressure regulator with a small flow rate only includes an inverted circular cone but does not include an auxiliary inverted circular cone, the step "(2) calculating the bottom cross-sectional air flow area S2 of the gradually opening interval according to the bottom cross-sectional air flow area S1 of the rectifying interval and the air supply variation coefficient q" in the above step 3 can be ignored; if the aforementioned anti-surge valve core structure of the pressure regulator with a small flow rate includes both an inverted circular cone and multiple auxiliary inverted circular cones, the bottom cross-sectional air flow areas of the multiple auxiliary inverted circular cones are calculated by the same method as the step "(2) calculating the bottom cross-sectional air flow area S2 of the gradually opening interval according to the bottom cross-sectional air flow area S1 of the rectifying interval and the air supply variation coefficient α" in step 3;

[0086] Step 4, calculating the bottom profile diameter D1 of the inverted circular truncated cone in the rectifying section according to the bottom cross-sectional gas flow area S1 of the rectifying section;

[0087]

[0088] Where:

[0089] D1——The bottom surface profile diameter of the inverted frustum of the rectifying section is a variable, unit: mm;

[0090] Then we get:

[0091] πD1 2 =πD 2 -4S1

[0092]

[0093] Substituting into formula 2, we get:

[0094]

[0095]

[0096] According to Formula 4, after inputting the rectifier interval travel h, the corresponding D1 diameter can be calculated; Note: the h value is not 0.

[0097] Step 4', calculating the bottom profile diameter D2 of the inverted circular truncated cone in the involute interval according to the bottom cross-section gas passing area S2 of the involute interval;

[0098] according to:

[0099]

[0100] Where:

[0101] D2——The bottom surface profile diameter of the involute interval secondary inverted frustum, which is a variable, unit: mm;

[0102] Substituting into formula 3, we get:

[0103]

[0104] Substituting into formula 2, we get:

[0105]

[0106] According to Formula 5, after inputting the ratio coefficient α of the gas passing area in the involute interval to the gas passing area in the rectifying interval and the stroke h of the rectifying zone, the corresponding D2 diameter can be calculated; Note: the h value is not 0.

[0107] When the aforementioned pressure regulator small flow anti-surge valve core structure only includes an inverted circular frustum but not an auxiliary inverted circular frustum, the above step 4' can be ignored; if the aforementioned pressure regulator small flow anti-surge valve core structure includes both an inverted circular frustum and multiple auxiliary inverted circular frustums, the bottom surface contour diameters of the multiple auxiliary inverted circular frustums are calculated using the same method as step 4';

[0108] Step 5, according to the throttling stroke h, the inner diameter D of the gas flow channel, the bottom surface profile diameter D1 of the rectifying section, and the bottom surface profile diameter D2 of the involute section, determine the shape and size of the entire anti-surge valve core, as follows:

[0109] The diameter D1 is calculated according to Formula 4; the shape and size of the inverted cone are determined by taking the throttling stroke h as the height of the inverted cone, the inner diameter D of the gas flow channel as the top diameter of the inverted cone, and D1 as the bottom diameter of the inverted cone; Note: the h value is not 0;

[0110] The diameter D2 is calculated according to Formula 5; the shape and size of the secondary inverted cone are determined by taking the throttling stroke h as the height of the secondary inverted cone, D1 as the top diameter of the secondary inverted cone, and D2 as the bottom diameter of the secondary inverted cone; Note: the h value is not 0;

[0111] Therefore, when the shape and size of the inverted circular frustum and the secondary inverted circular frustum are determined, the shape and size of the entire valve core are also determined;

[0112] In practical applications, the height of the inverted truncated cone and the height of the secondary inverted truncated cone can be designed to be β times the throttling stroke h according to the line flow characteristic requirements of the voltage regulator design, and the value of β is 1 to 2.5;

[0113] In addition, the top diameter of the inverted frustum is designed to be γ times the inner diameter D of the gas flow channel, and the value of γ is 0.8-1.

[0114] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0115] 1. The low-flow anti-surge valve core structure of the pressure regulator of the present invention designs the valve core in an inverted frustum shape. When the flow rate is small, the obstruction formed by the inverted frustum-shaped valve core to the gas flow channel changes linearly during the upward opening process, that is, the actual opening at a small flow rate is greater than the originally required opening, so that the pressure regulator avoids the most unstable position, thereby preventing the pressure regulator from frequent surges in the small flow range.

[0116] 2. The small flow rate anti-surge valve core structure of the voltage regulator of the present invention is designed with the valve core in the shape of an inverted cone, and a plurality of sub-inverted cones are provided on the bottom surface of the inverted cone, so that the inverted cone forms a rectifying section at the gas flow channel, and the sub-inverted cone forms a gradually opening section at the gas flow channel. The air flow area of ​​the rectifying section is small, so that the small flow rate working condition can be adapted by throttling. When the opening of the voltage regulator gradually exceeds the rectifying section, the air flow area of ​​the gradually opening section gradually increases to obtain a gradually increasing air flow volume, so that the voltage regulator gradually obtains flow gain, so as to stably transition to the normal air supply section, and realize the medium and large flow rate air supply of the voltage regulator. It can be seen that the small flow rate anti-surge valve core structure of the voltage regulator can prevent the voltage regulator from frequent surge in the small flow range, and at the same time does not affect the supply of large flow, and has strong practicality.

[0117] 3. The small flow anti-surge valve core structure of the pressure regulator of the present invention has a simple overall structure and strong adaptability. When used, it does not change the original main structure of the pressure regulator, nor does it need to deliberately reduce the specifications of the valve port of the pressure regulator. At the same time, it also does not require on-site debugging. It is simple and convenient to use and has good effects.

[0118] 4. The method for calculating the size of the small flow anti-surge valve core of the voltage regulator of the present invention takes the ideal gas state equation as the starting point, uses the basic condition that the working pressure and temperature of the voltage regulator remain unchanged under normal working conditions, combines the shape of the gas flow channel and the critical flow of the voltage regulator surge, and obtains the throttling stroke h of the voltage regulator through iterative calculation; then, according to the principle that the ratio of the cross-sectional gas flow area of ​​the rectifier interval to the total area of ​​the gas flow channel is equal to the ratio of the gas flow volume of the rectifier interval to the total gas flow volume of the gas flow channel, calculates the bottom surface contour diameter of the rectifier interval and the bottom surface contour diameter of the involute interval one by one, and finally determines the overall shape and size of the anti-surge valve core. This method can accurately calculate the valve core size for the critical flow q of the voltage regulator surge, the calculation method is reasonable, the final calculation formula obtained is simple, and it is convenient for rapid calculation, which greatly saves the design time of the valve core. At the same time, the accurate size calculation also ensures that the valve core structure can prevent the frequent surge of the voltage regulator in the small flow interval, and does not affect the supply of large flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0119] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0120] Figure 1 It is a schematic diagram of the static characteristic curve of the voltage regulator mentioned in the background technology.

[0121] Figure 2 It is a schematic diagram of the valve core structure of the present invention.

[0122] Figure 3 It is a schematic diagram of the positions of the rectifying section and the involute section described in the present invention.

[0123] Figure 4 Schematic diagram of the structure of the valve core in one embodiment of the present invention.

[0124] Reference numerals:

[0125] 1-valve body, 2-valve seat, 3-gas flow channel, 4-valve core, 4a-rectification interval, 4b-involute interval 41-inverted circular frustum, 42-sub-inverted circular frustum, 41a-angle I, 42a-angle II. DETAILED DESCRIPTION

[0126] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0127] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0128] First, the present invention provides a small flow anti-surge valve core structure of a pressure regulator, as one of the embodiments, such as Figure 2 As shown, the small flow anti-surge valve core structure of the pressure regulator includes a valve body 1, a gas flow channel 3 formed by a valve seat 2 and arranged in the valve body 1, and a valve core 4 arranged in the valve body and movably connected to the gas flow channel 3; the gas flow channel 3 is a vertical through hole with a consistent inner diameter, the valve core 4 is in the shape of an inverted frustum, and the top surface diameter of the inverted frustum 41 matches the inner diameter of the gas flow channel 3.

[0129] The surge of the pressure regulator occurs because the excessive flow capacity of the pressure regulator cannot adapt to the actual small flow demand, resulting in the phenomenon of violent fluctuations caused by the reciprocating switch of the valve trim. To solve the surge at small flow from the inside, it is necessary to avoid the original small opening interval of the pressure regulator through structural design, that is, to make the actual opening of the pressure regulator at small flow greater than the original required opening, so that the pressure regulator completely avoids the most unstable position. To make the initial opening of the pressure regulator larger than the original design value, it is necessary to use the principle of throttling, and effectively throttle the flow area of ​​the unstable opening position to make the flow volume at that position extremely small. In order to meet the downstream demand, the pressure regulator has to obtain a larger opening. In this embodiment, the valve core is designed to be an inverted cone. At a small flow, the inverted cone-shaped valve core 4 will form a linear obstruction to the gas flow channel 3 during the upward opening process, that is, the actual opening at a small flow is greater than the original required opening, so that the pressure regulator avoids the most unstable position, thereby preventing the pressure regulator from surging frequently in the small flow interval.

[0130] As an optional implementation scenario, in this implementation scenario, a secondary inverted frustum 42 is also provided on the bottom surface of the inverted frustum 41, the top surface area of ​​the secondary inverted frustum 42 is not larger than the bottom surface area of ​​the inverted frustum 41, and the center of the top surface of the secondary inverted frustum 42 coincides with the center of the bottom surface of the inverted frustum 41; the angle between the inclined surface of the secondary inverted frustum 42 and its top surface is smaller than the angle between the inclined surface of the inverted frustum 41 and its top surface.

[0131] As an optional implementation scenario, in this implementation scenario, the top surface of the secondary inverted cone 42 completely overlaps with the bottom surface of the inverted cone 41, and the shapes and sizes of the two are completely equal; at the same time, the angle II42a between the inclined surface of the secondary inverted cone 42 and its top surface is not greater than the angle I41a between the inclined surface of the inverted cone 41 and its top surface.

[0132] like Figure 3 As shown, by setting a secondary inverted circular cone 42 on the bottom surface of the inverted circular cone 41, the inverted circular cone 41 forms a rectifying section 4a at the gas flow channel 3, and the secondary inverted circular cone 42 forms an asymmetric section 4b at the gas flow channel 3. The gas flow area of ​​the rectifying section 4a is small, so that the small flow condition can be adapted by throttling. When the opening of the pressure regulator gradually exceeds the rectifying section 4a, the gas flow area of ​​the asymmetric section 4b gradually increases to obtain a gradually increasing gas flow, so that the pressure regulator gradually obtains flow gain, so as to stably transition to the normal gas supply section, and realize the medium and large flow gas supply of the pressure regulator. In this way, it can prevent the pressure regulator from frequent surge in the small flow section, and at the same time, it does not affect the supply of large flow.

[0133] As an optional implementation scenario, in this implementation scenario, the number of the secondary inverted frustum 42 is 2, the two secondary inverted frustums 42 are connected top to bottom, and the top surface of the secondary inverted frustum 42 located at the bottom completely overlaps with the bottom surface of the secondary inverted frustum 42 located at the top; the angle between the inclined surface of the secondary inverted frustum 42 located at the bottom and its top surface is smaller than the angle between the inclined surface of the secondary inverted frustum 42 located at the top and its top surface. Specifically, the difference between the angle between the inclined surface of the secondary inverted frustum 42 located at the bottom and its top surface and the angle between the inclined surface of the secondary inverted frustum 42 located at the top and its top surface is 25°.

[0134] By setting a plurality of secondary inverted circular frustums 42, in practical applications, the heights and bottom diameters of the plurality of secondary inverted circular frustums 42 can be adaptively calculated to obtain the optimal size that meets the working conditions, thereby satisfying the precise flow control from the rectifying interval to the gradually opening interval to the normal interval to the greatest extent, achieving a stable transition, and overcoming the surge phenomenon.

[0135] As an optional implementation scenario, in this implementation scenario, the edges of the connecting surfaces of the inverted truncated cone 41 and the auxiliary inverted truncated cone 42, and the edges of the connecting surfaces of the auxiliary inverted truncated cone 42 located above and the auxiliary inverted truncated cone 42 located below, are all rounded, that is, the side surface of the valve core 4 is a smooth curved surface; at the same time, in this embodiment, the inverted truncated cone 41 and the auxiliary inverted truncated cone 42 are integrally formed and manufactured. The setting of the integrally formed smooth curved surface makes the flow adjustment change softer and is more conducive to the stable transition of different intervals.

[0136] At the same time, the present invention also provides a gas pressure regulator, including a gas pressure regulating valve body, a valve core and a valve seat. The structure of the valve core is the above-mentioned small flow anti-surge valve core structure of the pressure regulator. Specifically, the valve core is arranged in the gas flow channel formed by the valve seat in the valve body, and is movably plugged with the flow channel; the flow channel is a vertical through hole with a consistent inner diameter, the valve core is in the shape of an inverted frustum, and the diameter of the top surface of the inverted frustum matches the inner diameter of the flow channel. In the process of the inverted frustum-shaped valve core opening upward, the obstruction formed on the gas flow channel changes linearly, that is, the actual opening at a small flow rate is greater than the original required opening, so that the pressure regulator avoids the most unstable position, thereby preventing the pressure regulator from frequent surges in the small flow range.

[0137] In order to enable the valve core structure of the present invention to be quickly used in pressure regulators of different specifications, based on the same inventive concept, the present invention also provides a method for calculating the structural dimensions of a small-flow anti-surge valve core of a pressure regulator. Through this method, the critical flow q of surge of pressure regulators of different specifications can be accurately calculated to determine the valve core dimensions suitable for the pressure regulator of that specification, thereby saving the design time of the valve core and ensuring that the valve core structure can prevent the frequent surge of the pressure regulator in a small flow range while not affecting the supply of large flow.

[0138] In an implementation scenario of the method for calculating the structural dimensions of a small flow rate anti-surge valve core of a pressure regulator of the present invention, the steps are:

[0139] Step 1, measuring the critical flow rate q of surge of the voltage regulator;

[0140] This example calculates the valve core size for a (M / 2") pressure regulator and finds that the critical flow rate q of the (M / 2") pressure regulator is 2500 Nm 3 / h;

[0141] It should be noted that the critical flow rate of surge of the voltage regulator is an environmental condition, and there are many methods for measuring it. The present invention does not specifically refer to a certain measurement method. As long as the critical flow rate of surge of the voltage regulator can be measured, it is within the protection rights of the present invention.

[0142] Step 2, calculating the throttling stroke h of the voltage regulator according to the ideal gas state equation and the critical flow rate of voltage regulator surge;

[0143] According to the ideal gas state equation:

[0144] PV=nRT

[0145] in,

[0146] P——Air pressure (absolute pressure)

[0147] V——Volume

[0148] n——molar amount of the substance

[0149] R——Universal gas constant (i.e., constants are equal under the same gas quality)

[0150] T——Thermodynamic temperature (Kelvin temperature, 1 thermodynamic temperature is: 273℃)

[0151] Under the premise that the working pressure and temperature of the voltage regulator remain unchanged, P, R, and T in the formula are all constants, so it can be seen that the variables V and n are in direct proportion.

[0152] V can be regarded as the flow space of the gas flow channel of the pressure regulator, and n can be regarded as the molar amount of gas that can pass through the gas flow channel of the pressure regulator. Therefore, the flow volume of the gas flow channel of the pressure regulator is proportional to the amount of gas that can pass through.

[0153] The gas flow channel of the pressure regulator is cylindrical in shape. According to the cylinder volume formula, the volume is proportional to the gas volume. Therefore, under the premise that the bottom area remains unchanged, the valve opening is also proportional to the gas volume, which conforms to the ratio of the linear flow characteristic.

[0154] Then the critical opening value formula of the voltage regulator surge can be obtained:

[0155] In this embodiment, the maximum design opening H of the (M / 2") voltage regulator is 12 mm, and the flow rate Q corresponding to the maximum design opening is 30000 Nm 3 / h, combined with the above measured critical flow rate q of the surge regulator is 2500Nm 3 / h, the critical opening value of the surge regulator (i.e. the throttling stroke value) h is 1mm;

[0156] Step 3, calculating the throttling area according to the throttling stroke h;

[0157] The throttling area determines the amount of gas that can pass through the throttling stroke. In this embodiment, the structural design of the valve core forms a throttling interval in the gas flow channel, and the throttling interval includes a rectifying interval formed by an inverted circular cone and an involute interval formed by a secondary inverted circular cone; wherein the rectifying interval is an interval covering the entire surge critical opening of the voltage regulator, so its span distance is not less than the throttling stroke h; in the involute interval, after the voltage regulator opening gradually exceeds the rectifying interval, the gas passing area should be gradually increased to obtain a gradually increasing gas passing volume, and the involute interval is through an involute curve structure, so that the voltage regulator gradually obtains flow gain.

[0158] (1) Calculate the bottom cross-sectional area S1 of the rectifier section

[0159] The gas flow area of ​​the rectifier section is to adapt to the small flow condition by throttling. Therefore, the gas flow area of ​​this section should be designed as a percentage of the surge critical flow of the regulator, that is, the ratio of the bottom cross-sectional gas flow area of ​​the rectifier section to the total area of ​​the gas flow channel, which is equal to the ratio of the rectifier gas flow volume to the total gas flow volume of the gas flow channel:

[0160] Therefore, we can get:

[0161]

[0162] In the formula,

[0163] S1——the bottom cross-sectional gas area of ​​the rectifier section, which is a variable, unit: mm 2 ;

[0164] S——Gas flow area of ​​the inner diameter of the gas flow channel, quantitative, unit: mm 2 ;

[0165] in,

[0166]

[0167] In the formula,

[0168] D——Inner diameter of gas flow channel, unit: mm;

[0169] Therefore, we can get:

[0170] Substituting the critical opening value formula of voltage regulator surge into the formula, we can get:

[0171] In this embodiment, the maximum design opening H of the (M / 2") voltage regulator is 12 mm, the inner diameter D of the gas flow channel is 46 mm, and the critical opening value of the voltage regulator surge (i.e., the throttling stroke value) h calculated above is 1 mm. The bottom cross-sectional gas flow area S1 of the rectifier interval can be calculated by the above formula to be 138.42 mm 2 ;

[0172] (2) Based on the bottom cross-sectional air flow area S1 of the rectifying interval and the air supply variation coefficient α, calculate the bottom cross-sectional air flow area S2 of the involute interval

[0173] The gradually opening interval is the transition section between the rectification interval and the normal interval. The air supply volume and the air supply volume change value in this interval should be greater than the rectification interval and less than the normal interval.

[0174] In order to maintain the linear characteristics, the corresponding coefficient is multiplied in the rectification interval calculation formula, that is:

[0175] S2=α×S1

[0176] Where:

[0177] S2——the bottom cross-section gas area of ​​the gradually opening interval, which is a variable, unit: mm 2

[0178] α is the ratio coefficient of the gas flow area in the involute interval to the gas flow area in the rectifier interval.

[0179] The value of α is determined according to the gas supply of the regulator, and is usually between 5 and 10. The (M / 2") regulator of this embodiment is a steady gas supply regulator, which requires a gentle involute curve, so the value of α is 9. Therefore, the bottom cross-sectional gas flow area S2 of the involute interval is 0.5*S1=69.21mm 2 ;

[0180] Step 4, calculating the bottom profile diameter D1 of the inverted circular truncated cone in the rectifying section according to the bottom cross-sectional gas flow area S1 of the rectifying section;

[0181]

[0182] Where:

[0183] D1——The bottom surface profile diameter of the inverted frustum of the rectifying section, unit: mm;

[0184] Then we get:

[0185] πD12 =πD 2 -4S1

[0186]

[0187] Substituting the calculation formula of the bottom cross-section gas area S1 of the rectifier section, we can get:

[0188]

[0189] In this embodiment, the maximum design opening H of the (M / 2") voltage regulator is 12 mm, the inner diameter D of the gas flow channel is 46 mm, and the critical opening value of the voltage regulator surge (i.e., the throttling stroke value) h calculated above is 1 mm. The bottom surface profile diameter D1 of the rectifier section can be calculated by the above formula to be 44.1 mm;

[0190] Step 4', calculating the bottom profile diameter D2 of the inverted circular truncated cone in the involute interval according to the bottom cross-section gas passing area S2 of the involute interval;

[0191] According to the formula of S2, the maximum to minimum diameter D2 of the involute zone can be calculated, and the shape and size of the anti-surge valve core can be determined.

[0192]

[0193] Where:

[0194] D2——The bottom surface profile diameter of the involute interval secondary inverted frustum, unit: mm;

[0195] Substituting the calculation formula of the bottom cross-section gas area S2 in the gradually opening interval, we can get:

[0196]

[0197] Substituting the bottom cross-sectional area S1 of the rectifier section into the calculation formula, we can get:

[0198]

[0199] In this embodiment, the maximum design opening H of the (M / 2") voltage regulator is 12 mm, the inner diameter D of the gas flow channel is 46 mm, the critical opening value of the voltage regulator surge (i.e., the throttling stroke value) h obtained by the above calculation is 1 mm, and the α value is 9. The bottom surface contour diameter D2 of the inverted frustum of the involute interval calculated by the above formula is 39.85 mm.

[0200] Step 5, through the above calculation, the valve core of the (M / 2”) pressure regulator has a throttling stroke h of 1 mm, a bottom surface profile diameter D1 of the rectifying section formed by the inverted circular cone is 44.1 mm, and a bottom surface profile diameter D2 of the involute section formed by the secondary inverted circular cone is 39.85 mm;

[0201] When β takes the value of 1, the height of the inverted cone and the height of the secondary inverted cone are consistent with the value of the throttling stroke h, which is 1mm; when Y takes the value of 1, the top diameter of the inverted cone is consistent with the inner diameter D of the gas flow channel, which is 46mm; thus, if Figure 4 As shown, the height of the inverted cone is 1mm, the top diameter is 46mm, and the bottom diameter is 44.1mm, and the shape and size of the inverted cone are confirmed; the height of the secondary inverted cone is 1mm, the top diameter is 44.1mm, and the bottom diameter is 39.85mm, and the shape and size of the secondary inverted cone are confirmed; when the shape and size of the inverted cone and the secondary inverted cone are determined, the shape and size of the entire valve core are also determined.

[0202] In the description of the present invention, it should be understood that the terms "front", "rear", "upper", "lower", "inside", "outside", "top", "bottom" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the products of the present invention are conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0203] At the same time, unless otherwise clearly stipulated and limited, the technical terms or scientific terms used in the present invention should have the usual meanings understood by persons with general skills in the field to which the present invention belongs. For example, the terms "setting", "connection", "installation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or a welding connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, for ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0204] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A small flow anti-surge valve core structure of a pressure regulator, characterized in that: It comprises a valve body, a gas flow channel formed by a valve port or a valve seat arranged in the valve body, and a valve core arranged in the valve body and movably connected to the flow channel; the flow channel is a vertical through hole with the same inner diameter, the valve core is in the shape of an inverted frustum, and the diameter of the top surface of the inverted frustum matches the inner diameter of the flow channel; The bottom surface of the inverted truncated cone is also provided with a secondary inverted truncated cone, the top surface area of ​​the secondary inverted truncated cone is not larger than the bottom surface area of ​​the inverted truncated cone, and the center of the top surface of the secondary inverted truncated cone coincides with the center of the bottom surface of the inverted truncated cone; the angle between the inclined surface of the secondary inverted truncated cone and its top surface is smaller than the angle between the inclined surface of the inverted truncated cone and its top surface; There are multiple secondary inverted frustums, and the multiple secondary inverted frustums are connected top to bottom, and the top surface of the secondary inverted frustum located at the bottom completely overlaps with the bottom surface of the secondary inverted frustum located at the top; the angle between the inclined surface of the secondary inverted frustum located at the bottom and its top surface is smaller than the angle between the inclined surface of the secondary inverted frustum located at the top and its top surface; The included angle between the inclined surface of the inverted circular frustum and its top surface is 75°, and the included angle between the inclined surface of the secondary inverted circular frustum connected to the bottom surface of the inverted circular frustum and its top surface is 55°.

2. The small flow anti-surge valve core structure of the pressure regulator according to claim 1 is characterized in that: The top surface of the secondary inverted circular frustum completely overlaps with the bottom surface of the inverted circular frustum.

3. The small flow anti-surge valve core structure of the pressure regulator according to claim 1 is characterized in that: The side surface of the valve core is a smooth curved surface.

4. A method for calculating the size of a small flow anti-surge valve core of a pressure regulator, characterized in that: The small flow anti-surge valve core of the pressure regulator comprises a valve body, a gas flow channel formed by a valve port or a valve seat arranged in the valve body, and a valve core arranged in the valve body and movably connected to the flow channel; the flow channel is a vertical through hole with a consistent inner diameter, the valve core is in the shape of an inverted frustum, and the top surface diameter of the inverted frustum matches the inner diameter of the flow channel; the method for calculating the size of the small flow anti-surge valve core of the pressure regulator comprises the following steps: Step 1, measuring the critical flow rate q of surge of the voltage regulator; Step 2, calculate the throttling stroke h of the pressure regulator based on the ideal gas state equation and the critical flow rate q of the pressure regulator surge: …Formula 1 In the formula, h——critical opening value of voltage regulator surge, also the throttling stroke value, unit: mm; H——maximum design opening of the voltage regulator, unit: mm; q——critical flow rate of surge of voltage regulator, unit: Nm 3 / h; Q——Flow rate corresponding to the maximum design opening of the pressure regulator, unit: Nm 3 / h; Step 3, calculate the throttling area according to the throttling stroke h; the throttling area is the bottom cross-sectional air flow area S1 of the rectifying interval formed by the inverted frustum: …Formula 2 In the formula, D——Inner diameter of gas flow channel, unit: mm; S1——the bottom cross-sectional gas area of ​​the rectifier section, which is a variable, unit: mm 2 ; Step 4, calculating the bottom profile diameter D1 of the inverted circular truncated cone in the rectifying section according to the bottom cross-sectional gas flow area S1 of the rectifying section; Where: D1——The bottom surface profile diameter of the inverted frustum of the rectifying section, unit: mm; Step 5, using the throttling stroke h as the height of the inverted cone, the inner diameter D of the gas flow channel as the top diameter of the inverted cone, and D1 as the bottom diameter of the inverted cone, determine the shape and size of the entire anti-surge valve core.

5. The method for calculating the size of a small flow anti-surge valve core of a pressure regulator according to claim 4 is characterized in that: The throttling stroke h of the voltage regulator is greater than 0 and less than 1 / 2 of the maximum design opening H of the voltage regulator.

6. The method for calculating the size of a small flow anti-surge valve core of a pressure regulator according to claim 4 is characterized in that: The height of the inverted frustum is β times the throttling stroke h, and the value of β is 1-2.5; the top surface diameter of the inverted frustum is γ times the inner diameter D of the gas flow channel, and the value of γ is 0.8-1.

7. The method for calculating the size of a small flow anti-surge valve core of a pressure regulator according to claim 4, characterized in that: The bottom surface of the inverted truncated cone is also provided with a secondary inverted truncated cone, the top surface area of ​​the secondary inverted truncated cone is not larger than the bottom surface area of ​​the inverted truncated cone, and the center of the top surface of the secondary inverted truncated cone coincides with the center of the bottom surface of the inverted truncated cone; the angle between the inclined surface of the secondary inverted truncated cone and its top surface is smaller than the angle between the inclined surface of the inverted truncated cone and its top surface; In step 3 of the method for calculating the size of the small flow anti-surge valve core of the pressure regulator, the throttling area also includes the bottom cross-sectional air flow area S2 of the involute interval formed by the secondary inverted frustum. The bottom cross-sectional air flow area S2 of the involute interval is calculated by the formula: …Formula 3 Where: S2——the bottom cross-section gas area of ​​the gradually opening interval, which is a variable, unit: mm 2 ; α——The ratio coefficient of the gas flow area in the involute interval to the gas flow area in the rectifier interval; The method for calculating the size of a small flow anti-surge valve core of a pressure regulator further includes step 4', which is: According to the bottom cross-section gas area S2 of the involute interval, calculate the bottom contour diameter D2 of the involute interval inverted frustum: …Formula 5 Step 5 of the method for calculating the size of the small flow anti-surge valve core of the pressure regulator is: The shape and size of the inverted cone are determined by taking the throttling stroke h as the height of the inverted cone, the inner diameter D of the gas flow channel as the top diameter of the inverted cone, and D1 as the bottom diameter of the inverted cone; the shape and size of the secondary inverted cone are determined by taking the throttling stroke h as the height of the secondary inverted cone, D1 as the top diameter of the secondary inverted cone, and D2 as the bottom diameter of the secondary inverted cone; the shape and size of the entire anti-surge valve core are determined according to the shape and size of the inverted cone and the shape and size of the secondary inverted cone; wherein the height of the inverted cone and the height of the secondary inverted cone are β times of the throttling stroke h, and the value of β is 1~2.

5.

8. The method for calculating the size of a small flow anti-surge valve core of a pressure regulator according to claim 7, characterized in that: The ratio coefficient α of the gas flow area in the involute interval to the gas flow area in the rectifying interval has a value ranging from 5 to 10.

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