Method for generating double-elliptical membrane cavity profile with adjustable inflection point slope and diaphragm compressor

Abstract

The application discloses a method for generating a double-ellipse membrane cavity profile with adjustable inflection point slope and a diaphragm compressor. The method comprises determining a characteristic ellipse and an inflection point inclination angle, wherein the inflection point inclination angle represents the inclination angle of a connection point between a profile segment L1 and a profile segment L2 in an X'O'Y' coordinate system; determining an arbitrary point P on the characteristic ellipse and a characteristic point Q on the characteristic ellipse, wherein the Q point is a transcendental point, and the P point is a chasing point, thereby determining an ellipse segment PQ with a fixed inflection point slope inclination angle under the characteristic ellipse; solving the arbitrary chasing point P on the characteristic ellipse and the corresponding transcendental point Q, and obtaining all profile segment PQ ellipse line clusters under the characteristic inflection point inclination angle, so as to obtain the radius and deflection range of the membrane cavity profile formed by the PQ ellipse line clusters; and combining and connecting different two PQ ellipse profile lines L1 and L2 to form a complete diaphragm compressor membrane cavity profile L, so as to meet the requirements of the diaphragm compressor membrane cavity profile. The application improves the diaphragm life and the whole machine reliability through the optimization design of multiple parameters.

Description

Technical Field

[0001] This invention relates to the field of diaphragm compressor technology, specifically to a method for generating a double elliptical diaphragm cavity profile with adjustable inflection point slope and a diaphragm compressor. Background Technology

[0002] A diaphragm compressor is a positive displacement compressor that separates the oil and gas sides using a diaphragm. Its working principle is as follows: a motor drives a crankshaft connecting rod, which in turn drives a piston in reciprocating motion to pressurize and depressurize high-pressure oil. This high-pressure oil then pushes the diaphragm to compress and discharge the gas. Due to its excellent sealing and high pressure ratio, diaphragm compressors are widely used in the hydrogen energy industry, especially in hydrogen refueling stations. However, diaphragm lifespan, volumetric efficiency, and diaphragm head strength are critical and challenging issues in the development of diaphragm compressors. The diaphragm is a key component for the stable operation of a diaphragm compressor, and its performance directly affects the reliability of the compressor. During diaphragm failure, the main forms of damage are collapse, torsional deformation, wear cracks, and mechanical fatigue. Damage to the diaphragm will lead to the destruction of its mechanical properties, and in severe cases, even significant economic losses.

[0003] Currently, the diaphragm compressor cavity profile widely used in China is the single-index small-deflection diaphragm cavity profile, which has proven to have good reliability and a solid practical foundation through long-term practice and verification. However, in the development and design of new diaphragm compressor models, the traditional single-index diaphragm cavity profile is adjusted by three profile variables: cavity radius, single index, and maximum deflection. This limits the optimization range and makes it difficult to adjust for diaphragm stress changes caused by variations in the slope of the diaphragm cavity profile inflection point. This fails to meet the urgent market demands for diaphragm compressor technology development and the research and development of new high-pressure, high-speed models. Multi-parameter diaphragm cavity profile optimization design is an effective way to improve the reliability and reduce the cost of diaphragm compressors. Summary of the Invention

[0004] The purpose of this invention is to address the problems in the prior art by providing a method for generating a double elliptical membrane cavity profile with adjustable inflection point slope and a diaphragm compressor. This method overcomes the problems of insufficient optimization parameters, limited optimization range, and difficulty in adjusting the inflection point slope in traditional single exponential profile design, adapting to diverse market demands, optimizing the reliability of the diaphragm compressor, and increasing diaphragm life.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] Firstly, a method for generating a double elliptical membrane cavity profile with adjustable inflection point slope is provided, comprising:

[0007] Determine the characteristic ellipse S and the inclination angle of the initially selected inflection point. Establish an XOY coordinate system with the center of ellipse S as the origin, the major axis as the X-axis, and the minor axis as the Y-axis; define the inflection angle at the inflection point. The angle of inclination of the connection point between line segment L1 and line segment L2 in the X'O'Y' coordinate system;

[0008] Determine any point P on the characteristic ellipse S, whose coordinates pass through (acosθ). P bsinθ P The description is as follows: A feature point Q on the feature ellipse S is defined, with coordinates obtained through (acosθ). Q bsinθ Q The description is as follows: Q is defined as the overtaking point and P is defined as the catching-up point, thereby determining the elliptical segment PQ with a fixed inflection point slope and inclination angle under the characteristic ellipse S.

[0009] Perform a coordinate transformation on the elliptical segment PQ in the XOY coordinate system to form a new coordinate system X'O'Y' with point P as the origin, the tangent line Line_P at point P as the X-axis, and the PQ segment located in the first quadrant of the new coordinate system. This yields the point coordinates (x', y') of the characteristic ellipse S in the X'O'Y' coordinate system and the representation of the PQ-type line segment L1, thus obtaining the inclination angle of the characteristic inflection point on the characteristic ellipse S. Arbitrary elliptical line segment PQ;

[0010] Solve for any chasing point P and its corresponding surpassing point Q on the characteristic ellipse S, and obtain the inclination angle of the characteristic inflection point. The radius and deflection range of the membrane cavity profile formed by the PQ elliptical line clusters are obtained from all the PQ elliptical line clusters.

[0011] According to the design requirements of the diaphragm compressor membrane head profile, two different PQ elliptical profiles L1 and L2 are combined and connected to form a complete diaphragm compressor membrane cavity profile L, which meets the requirements of the diaphragm compressor membrane cavity profile.

[0012] As a preferred embodiment, the characteristic ellipse S is described by the following formula:

[0013]

[0014] In the formula: a is the length of the major axis of the characteristic ellipse S; b is the length of the minor axis of the characteristic ellipse S; θ is the characteristic angle of the characteristic ellipse S; (x, y) is the coordinate of any point on the characteristic ellipse S in the XOY coordinate system.

[0015] As a preferred embodiment, the coordinates (acosθ) of any point P on the characteristic ellipse S P bsinθ P The coordinates (acosθ) of the feature point Q on the feature ellipse S. Q bsinθ Q The following conditions must be met between them:

[0016]

[0017] The positive direction is the counterclockwise rotation along the characteristic ellipse S. Point Q is directly in front of point P. The overtaking point Q, obtained from the chasing point P and satisfying the above conditions, has two solutions. Let |θ| Q -θ P The smaller Q point is used as the definition transcendental point Q.

[0018] As a preferred embodiment, the steps for performing coordinate transformation on the elliptical segment PQ in the XOY coordinate system are as follows:

[0019]

[0020] This gives the coordinates (x', y') of the characteristic ellipse S in the new coordinate system X'O'Y'. The PQ-type line segment L1 is described by the following formula:

[0021] L1=[x'(θ),y'(θ)]θ∈(θ P ,θ Q )

[0022] This yields the inclination angle of the characteristic inflection point on the characteristic ellipse S. Any elliptical line segment PQ.

[0023] As a preferred embodiment, in the X'O'Y' coordinate system, the length RA of the PQ line cluster in the X' direction can be described by the following formula:

[0024]

[0025] The length HA of the PQ line bundle in the Y' direction can be described by the following formula:

[0026]

[0027] The radius and deflection range of the membrane cavity profile formed by the PQ elliptical line cluster are obtained:

[0028]

[0029] As a preferred embodiment, when combining and connecting two different PQ elliptical lines L1 and L2 to form a complete diaphragm compressor membrane cavity profile L according to the design requirements of the diaphragm compressor membrane head profile, the following formula is used for calculation:

[0030]

[0031] In the formula: D represents the differentiation operation; R maxThe maximum radius of the membrane cavity profile L of the combined diaphragm compressor is defined as the sum of the lengths of the two PQ elliptical profiles L1 and L2.

[0032] As a preferred embodiment, the expression for the double elliptical membrane cavity profile is as follows:

[0033]

[0034] The combined elliptical line has the following characteristics:

[0035]

[0036] In the formula: R L The membrane cavity radius represents the membrane cavity profile L of the combined diaphragm compressor; k P This represents the slope of the inclination angle of the inflection point P connecting the L1 and L2 line segments in the membrane cavity profile L of the combined diaphragm compressor in the X'O'Y' coordinate system.

[0037] As a preferred option, the method also includes performing diaphragm surface stress analysis on the diaphragm compressor with the combined diaphragm compressor diaphragm cavity profile L, checking whether it meets the allowable stress requirements of the diaphragm, and if not, optimizing the design or redesigning it by adjusting the inflection point slope.

[0038] As a preferred option, the maximum and minimum surface stress of the diaphragm compressor diaphragm with the combined diaphragm compressor cavity profile L when deformed to closely fit the cavity surface are calculated using the following formula:

[0039]

[0040] δ min =min{σ Pr ±σ Mr ,σ Pt ±σ Mt}

[0041] δ max =max{σ Pr ±σ Mr ,σ Pt ±σ Mt}

[0042] In the formula, H is the equation of the membrane cavity profile with respect to radius r; E is the Young's modulus of the membrane material; μ is the Poisson's ratio of the membrane material; t is the membrane thickness; ∫ represents the integral operation; d represents the differential operation; σ Pr The radial normal stress of the diaphragm; σ Pt σ is the circumferential normal stress of the diaphragm; Mr For the radial shear stress of the diaphragm; σ Mr For the circumferential shear stress of the diaphragm; δ min The minimum stress on the diaphragm surface; δmax This represents the maximum stress on the diaphragm surface.

[0043] In a second aspect, a diaphragm compressor is provided, having a diaphragm compressor head designed according to a double elliptical diaphragm cavity profile generation method with adjustable inflection point slope.

[0044] Compared with the prior art, the present invention has at least the following beneficial effects:

[0045] The double elliptical membrane cavity profile generation method with adjustable inflection point slope of this invention can generate a combined membrane cavity profile with controllable inflection points. This profile satisfies the surface conditions required for the membrane cavity profile of a diaphragm compressor, and has an ellipse with a major axis length 'a', a minor axis length 'b', and an inflection point inclination angle. Membrane cavity radius R L Membrane cavity deflection H L Characteristic angle θ generated by the profile P It offers multiple design parameters, including optional curve clusters, and features inflection point inclination angles. The adjustable feature overcomes the problems of insufficient optimization parameters, limited optimization range, and difficulty in adjusting the inflection point slope in traditional diaphragm cavity profile design. It is beneficial to optimize the variation range of the inflection point slope of the diaphragm cavity profile and optimize the stress distribution on the diaphragm surface, making the profile design more flexible and better adaptable to changing design conditions and market demands. Multi-parameter optimization design helps improve the diaphragm life and overall reliability of the diaphragm compressor. Attached Figure Description

[0046] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art are briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is a schematic diagram of a method for generating a double elliptical membrane cavity profile with adjustable inflection point slope according to an embodiment of the present invention;

[0048] Figure 2 This is a schematic diagram of the two-segment profile combination of the double elliptical membrane cavity profile generation method with adjustable inflection point slope according to an embodiment of the present invention;

[0049] Figure 3 This is a schematic diagram of the characteristic elliptical line cluster controlling the inflection point slope in Embodiment 1 of the present invention;

[0050] Figure 4 This is a graph showing the maximum radius of the characteristic elliptical line cluster controlling the inflection point slope as a function of the characteristic angle in Embodiment 1 of the present invention.

[0051] Figure 5 This is a graph showing the maximum deflection of the characteristic elliptical line cluster controlling the inflection point slope as a function of the characteristic angle in Embodiment 1 of the present invention.

[0052] Figure 6 This is a schematic diagram of the characteristic elliptical line cluster combination membrane cavity profile for controlling the inflection point slope in Embodiment 1 of the present invention;

[0053] Figure 7 This is a schematic diagram of the double elliptical membrane cavity profile with maximum deflection under the condition of characteristic ellipse and characteristic inflection point slope in Embodiment 1 of the present invention;

[0054] Figure 8 This is a schematic diagram of the double elliptical membrane cavity profile with maximum deflection under the conditions of the characteristic ellipse and the characteristic inflection point slope in Embodiment 2 of the present invention;

[0055] Figure 9 This is a graph showing the maximum and minimum stress variation along the radial direction on the diaphragm surface of the diaphragm compressor in Embodiment 2 of the present invention.

[0056] Icons: XOY - Coordinate system for generating the feature ellipse; S - Feature ellipse; P - A point on the feature ellipse, defined as the catching-up point; Q - A point on the feature ellipse, defined as the surpassing point; Line_P - Tangent line of the feature ellipse at point P; Line_Q - Tangent line of the feature ellipse at point Q; The angle between the line and Line_Q; θ P -The characteristic angle of point P on the characteristic ellipse; θ Q -The characteristic angle of point Q on the characteristic ellipse; The angle of inclination of a point in the XOY coordinate system; The inclination angle of a point in the XOY coordinate system; D1 - distance of point P from Line_Q; D2 - distance of point Q from Line_P; L1 - first elliptical line; L2 - second elliptical line; X'O'Y' - coordinate system with point P as the origin and D1 as the abscissa; PQ line cluster - the set of elliptical segment line clusters after coordinate transformation under the characteristic inflection point slope of the characteristic ellipse; A1 - the first type of line composition method from the A region type line segment of the PQ line cluster; B1 - the first type of line composition method from the B region type line segment of the PQ line cluster. A type of profile composition; A2 - a second type of profile composition from region A of the PQ line cluster; B2 - a second type of profile composition from region B of the PQ line cluster; Region A cluster - the portion of the PQ line cluster located in the first quadrant; Region B cluster - the portion of the PQ line cluster located in the third quadrant; Q-point cluster - the set of Q-point positions of the PQ line cluster; RA - the D1 length of the PQ line cluster, i.e., the maximum radius of the profile forming the cavity; HA - the D2 length of the PQ line cluster, i.e., the maximum deflection of the profile forming the cavity; θ P - Characteristic angle of point P on the characteristic ellipse; H - Deflection equation of the combined double ellipse cavity profile. Detailed Implementation

[0057] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0058] like Figures 1 to 2 As shown, the method for generating a double elliptical membrane cavity profile with adjustable inflection point slope according to an embodiment of the present invention includes:

[0059] Step 1: Determine the characteristic ellipse S and the initial inflection point angle. Establish an XOY coordinate system with the center of ellipse S as the origin, the major axis as the X-axis, and the minor axis as the Y-axis. Define the inflection angle at the inflection point. The inclination angle of the connection point between line segments L1 and L2 in the X'O'Y' coordinate system. The characteristic ellipse S can be described by the following formula:

[0060]

[0061] In the formula: a is the length of the major axis of the characteristic ellipse S; b is the length of the minor axis of the characteristic ellipse S; θ is the characteristic angle of the characteristic ellipse S; (x, y) is the coordinate of any point on the characteristic ellipse S in the XOY coordinate system.

[0062] Step 2: Determine any point P on the feature ellipse S, whose coordinates can be expressed as (acosθ). P bsinθ P The description is as follows: A feature point Q on the feature ellipse S is defined, and its coordinates are expressed by (acosθ). Q bsinθ Q Describe the following conditions:

[0063]

[0064] The positive direction is the counterclockwise rotation along the characteristic ellipse S. Point Q is directly in front of point P; therefore, point Q is defined as the overtaking point, and point P as the catching-up point. There are two solutions for the overtaking point Q that satisfy the above conditions, obtained from the catching-up point P. Let |θ| Q -θ P The smaller point Q is used as the defining transcendent point Q. This determines the elliptical segment PQ with a fixed inflection point slope and inclination angle under the characteristic ellipse S.

[0065] Step 3: Perform coordinate transformation on the elliptical segment PQ in the XOY coordinate system to form a new coordinate system X'O'Y' with point P as the origin, the tangent line Line_P at point P as the X-axis direction, and the PQ segment located in the first quadrant of the new coordinate system. The specific coordinate transformation process is as follows:

[0066]

[0067] This gives the coordinates (x', y') of the characteristic ellipse S in the new coordinate system X'O'Y'. The PQ-type line segment L1 can be described by the following formula:

[0068] L1=[x'(θ),y'(θ)]θ∈(θ P ,θ Q )

[0069] This yields the inclination angle of the characteristic inflection point on the characteristic ellipse S. Any elliptical line segment PQ.

[0070] Step 4: Solve for any chasing point P and its corresponding surpassing point Q on the characteristic ellipse S, and obtain the inclination angle of the characteristic inflection point. For all PQ line clusters of the following type, in the X'O'Y' coordinate system, the length RA of the PQ line cluster in the X' direction can be described by the following formula:

[0071]

[0072] The length HA of the PQ line bundle in the Y' direction can be described by the following formula:

[0073]

[0074] The radius and deflection range of the membrane cavity profile formed by the PQ elliptical line cluster can be obtained:

[0075]

[0076] Based on the design requirements of the diaphragm compressor membrane head profile, two different PQ elliptical profiles, L1 and L2, are combined and connected to form a complete diaphragm compressor membrane cavity profile L, which meets the general requirements of the diaphragm compressor membrane cavity profile. Specifically, it is described as follows:

[0077]

[0078] In the formula: D represents the differentiation operation; R max The maximum radius of the membrane cavity profile L of the combined diaphragm compressor is defined as the sum of the lengths of the two PQ elliptical profiles L1 and L2.

[0079] Furthermore, the double elliptical membrane cavity profile of this embodiment of the invention is described as follows:

[0080]

[0081] Therefore, the combined elliptic line has the following characteristics:

[0082]

[0083] In the formula: R L The membrane cavity radius represents the membrane cavity profile L of the combined diaphragm compressor; k P This represents the slope of the inclination angle of the inflection point P connecting the L1 and L2 line segments in the membrane cavity profile L of the combined diaphragm compressor in the X'O'Y' coordinate system.

[0084] Step 5: Perform diaphragm surface stress analysis on the diaphragm compressor using the above-mentioned double elliptical diaphragm cavity profile L with adjustable inflection point slope, and check whether it meets the allowable stress requirements of the diaphragm. If it does not meet the requirements, the design can be optimized or redesigned by adjusting the inflection point slope.

[0085] The theoretical formulas for calculating the maximum and minimum surface stress of the diaphragm compressor diaphragm when deformed to closely fit the membrane cavity surface, using the membrane cavity profile described in this embodiment of the invention, are as follows:

[0086]

[0087] δ min =min{σ Pr ±σ Mr ,σ Pt ±σ Mt}

[0088] δ max =max{σ Pr ±σ Mr ,σ Pt ±σ Mt}

[0089] In the formula, H is the equation of the membrane cavity profile with respect to radius r; E is the Young's modulus of the membrane material; μ is the Poisson's ratio of the membrane material; t is the membrane thickness; ∫ represents the integral operation; d represents the differential operation; σ Pr The radial normal stress of the diaphragm; σ Pt σ is the circumferential normal stress of the diaphragm; Mr For the radial shear stress of the diaphragm; σ Mr For the circumferential shear stress of the diaphragm; δ min The minimum stress on the diaphragm surface; δ max This represents the maximum stress on the diaphragm surface.

[0090] Furthermore, through the double elliptical membrane cavity profile generation method with adjustable inflection point slope described in the above embodiments of the present invention, a combined membrane cavity profile with controllable connection inflection points can be generated, which meets the surface conditions required by the membrane cavity profile of the diaphragm compressor. Moreover, by adjusting the inflection point slope, the stress distribution of the membrane cavity profile can be made more uniform, reducing the stress distribution non-uniformity of the diaphragm, improving the diaphragm life and the overall reliability of the diaphragm compressor.

[0091] This invention also proposes a diaphragm compressor having a diaphragm compressor head designed according to the method for generating a double elliptical diaphragm cavity profile with adjustable inflection point slope.

[0092] Example 1

[0093] This embodiment provides an example of a method for generating the double elliptical membrane cavity profile of a diaphragm compressor.

[0094] Specifically, such as Figure 2 As shown, the major axis of the characteristic ellipse S is defined as a = 500 mm, the minor axis as b = 300 mm, and the inflection angle at the inflection point is defined as...

[0095] Specifically, such as Figure 3 As shown, the solution yields the elliptical arc segment PQ line cluster and its different partitions A and B between the catching point P and the surpassing point Q of the ellipse S under the characteristic inflection point slope.

[0096] Specifically, such as Figure 4 As shown, in the curve of the PQ line cluster radius RA of the characteristic ellipse S changing with the characteristic angle θ, it can be seen that the changing radius RA of the curve cluster PQ is ∈ [15, 65] mm.

[0097] Specifically, such as Figure 5 As shown, in the curve of the deflection HA of the PQ line cluster of the characteristic ellipse S as a function of the characteristic angle θ, it can be seen that the deflection HA of the curve cluster PQ is ∈ [0.55, 2.55] mm.

[0098] Specifically, such as Figure 6 As shown, the first elliptical line L1 of the generation profile adopts the elliptical characteristic line segment with the largest radius in the PQ curve cluster, while the second elliptical line L2 adopts the elliptical characteristic line segments of all PQ curve clusters, forming the double elliptical membrane cavity profile line cluster of the diaphragm compressor shown in the figure.

[0099] Specifically, such as Figure 7 As shown, the first elliptical line L1 and the second elliptical line L2 both adopt the elliptical characteristic line segment with the largest radius in the PQ curve cluster, and are continuously spliced ​​to form a complete membrane cavity line segment L. The equation of the membrane cavity line is as follows:

[0100]

[0101] Specifically, the above steps form a double elliptical membrane cavity profile with a slope of 0.00137 rad at the inflection point where the two elliptical lines meet. This profile can be adjusted by... Adjust the profile.

[0102] Example 2

[0103] This embodiment provides an example of a method for generating the double elliptical membrane cavity profile of a diaphragm compressor.

[0104] Specifically, the major axis of the characteristic ellipse S is defined as a = 1000 mm, the minor axis as b = 300 mm, and the inflection angle at the inflection point is defined as... The elliptical line segment with the largest radius RA in the family of profile curves generated by this characteristic ellipse is selected as the first membrane cavity profile L1 and the second membrane cavity profile L2. The resulting membrane cavity profile is described as follows:

[0105]

[0106] For ease of stress calculation, L=(x') in the above profile equation is... L ,y' L Perform the following coordinate transformations:

[0107] L end =[x' L ,max(y' L )-y' L ]

[0108] This allows us to obtain the membrane cavity profile L formed by the connection. end like Figure 8 As shown.

[0109] Specifically, for the application of the above-mentioned membrane cavity profile L end The stress distribution on the surface of the diaphragm of the diaphragm compressor was calculated by stress analysis. Figure 9 As shown, the maximum stress of the double elliptical membrane cavity profile in this embodiment is approximately 175 MPa.

[0110] This invention proposes a method for generating a double elliptical membrane cavity profile with adjustable inflection point slope and a diaphragm compressor, which has an ellipse with major axis length a, minor axis length b, and inflection point tilt angle. Membrane cavity radius R L Membrane cavity deflection H L Characteristic angle θ generated by the profile P It offers multiple design parameters, including optional curve clusters, and features inflection point inclination angles. The adjustable feature is beneficial for optimizing the inflection point slope of the diaphragm cavity profile and optimizing the stress distribution on the diaphragm surface. Compared with the traditional single-index diaphragm cavity profile, it has more profile design parameters, making the profile design more flexible and adaptable to changing design conditions and market demands. Through multi-parameter optimization design, it is beneficial to improve the diaphragm life and overall reliability of the diaphragm compressor.

[0111] Although this application has been described above with reference to specific embodiments, those skilled in the art will understand that many modifications can be made to the configurations and details disclosed in this application within the principles and scope of the disclosure. The scope of protection of this application is determined by the appended claims, and the claims are intended to cover all modifications included in the literal meaning or scope of equivalents of the technical features in the claims.

Claims

1. A method for generating a double-elliptical membrane cavity profile with adjustable inflection point slope, characterized in that, include: Determine the characteristic ellipse S and the initial inflection point inclination An XOY coordinate system is established with the center of the ellipse S as the origin, the major axis as the X axis, and the minor axis as the Y axis; define the inflection point inclination , which represents the inclination of the connection point of the line segment L1 and the line segment L2 in the X'O'Y' coordinate system; A point P on the characteristic ellipse S is determined, with coordinates given by are described; The characteristic point Q on the characteristic ellipse S is defined, with coordinates by are described; the Q point is defined as the transcendental point and the P point is defined as the chasing point, thus determining the elliptic segment PQ under the fixed inflection point slope inclination of the characteristic ellipse S; The ellipse segment PQ in the XOY coordinate system is subjected to coordinate transformation to form a coordinate system X'O'Y' with P as the coordinate origin, the tangent line Line_P of P as the X axis direction, and the PQ line segment in the first quadrant of the new coordinate system; and the point coordinates of the characteristic ellipse S in the coordinate system X'O'Y' are obtained and the representation of the PQ type line segment L1, to obtain the inclination angle of the characteristic inflection point on the characteristic ellipse S arbitrary ellipse type line segment PQ; Solve the characteristic ellipse S on any catch point P and its corresponding transcendental point Q, and obtain the characteristic inflection point inclination All the type line segment PQ ellipse line cluster, get the radius and deflection range of the membrane cavity type line surrounded by PQ ellipse line cluster; According to the design requirements of the membrane head profile of the diaphragm compressor, two different PQ elliptical profiles L1 and L2 are combined and connected to form a complete membrane cavity profile L of the diaphragm compressor, which meets the requirements of the membrane cavity profile of the diaphragm compressor. The characteristic ellipse S is described by the following formula: wherein: is the length of the major axis of the characteristic ellipse S; is the length of the minor axis of the characteristic ellipse S; is the characteristic angle of the characteristic ellipse S; ( x , y ) are the coordinates of any point on the characteristic ellipse S in the XOY coordinate system; Any point P on the characteristic ellipse S coordinates with the coordinates of the characteristic point Q on the characteristic ellipse S satisfy the following condition: The clockwise direction of rotation along the characteristic ellipse S is the positive direction, and the point Q is in front of the point P in the positive direction. There are two solutions for the transcendental point Q that satisfies the above conditions, and the smaller Q point is taken as the definition of the transcendental point Q. The clockwise direction of rotation along the characteristic ellipse S is the positive direction, and the point Q is in front of the point P in the positive direction. There are two solutions for the transcendental point Q that satisfies the above conditions, and the smaller Q point is taken as the definition of the transcendental point Q.

2. The inflection point slope-adjustable double-elliptical membrane cavity type line generating method according to claim 1, wherein The steps for performing coordinate transformation on the elliptical segment PQ in the XOY coordinate system are as follows: The point coordinates of the characteristic ellipse S in the new coordinate system X'O'Y' are thus obtained The PQ-type line segment L1 is described by the following equation: Thus any elliptic segment PQ on the characteristic ellipse S is obtained with the characteristic inflection point inclination of the characteristic ellipse S.

3. The method for generating a double elliptical membrane cavity profile with adjustable inflection point slope according to claim 2, characterized in that, The length of the cluster of lines PQ in the X' direction under the X'Y' coordinate system This can be described by the following equation: Length of the cluster of PQ lines in the Y' direction This can be described by the following equation: The radius and deflection range of the membrane cavity profile formed by the PQ elliptical line cluster are obtained: 。 4. The inflection point slope-adjustable double-elliptical membrane cavity type line generating method according to claim 3, wherein When combining and connecting two different PQ elliptical lines L1 and L2 to form a complete diaphragm compressor membrane cavity profile L according to the design requirements of the diaphragm compressor membrane head profile, the following formula is used for calculation: In the formula, D represents a derivation operation. The maximum radius of the membrane cavity profile L of the combined diaphragm compressor is defined as the sum of the lengths of two PQ elliptical profile L1 and L2. The maximum radius of the membrane cavity profile L of the combined diaphragm compressor is defined as the sum of the lengths of two PQ elliptical profile L1 and L2.

5. The inflection point slope adjustable bi-elliptical membrane cavity profile generating method according to claim 3, wherein, The expression for the double elliptical cavity profile with adjustable inflection point slope is as follows: The combined elliptical line has the following characteristics: In the formulae: represents the membrane cavity radius of the membrane cavity profile L of the combined diaphragm compressor; represents the inclination slope of the connecting inflection point P of the L1 profile segment and the L2 profile segment in the membrane cavity profile L of the combined diaphragm compressor in the X'O'Y' coordinate system.

6. The inflection point slope-adjustable double-elliptical membrane cavity type line generating method according to claim 5, wherein It also includes performing diaphragm surface stress analysis on the diaphragm compressor with the diaphragm cavity profile L after the application of the combined diaphragm compressor, checking whether it meets the allowable stress requirements of the diaphragm, and if not, optimizing the design or redesigning it by adjusting the inflection point slope.

7. The inflection point slope-adjustable double-elliptical membrane cavity type line generating method according to claim 6, wherein The maximum and minimum surface stresses of the diaphragm compressor diaphragm with the combined diaphragm compressor cavity profile L when deformed to closely fit the cavity surface are calculated using the following formula: In the formula, For about radius r The equation for the membrane cavity profile; Young's modulus of the diaphragm material; Poisson's ratio of the diaphragm material; For diaphragm thickness; Indicates integration operation; Represents differentiation operations; This refers to the radial normal stress of the diaphragm. The circumferential normal stress of the diaphragm; This refers to the radial shear stress of the diaphragm. This refers to the circumferential shear stress of the diaphragm. This represents the minimum stress on the diaphragm surface. This represents the maximum stress on the diaphragm surface.

8. A diaphragm compressor, characterized in that, A diaphragm compressor head designed with a double elliptical membrane cavity profile generation method with adjustable inflection point slope as described in any one of claims 1 to 7.

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