Method for generating molded line of double elliptical diaphragm cavity with adjustable inflection point slope and diaphragm compressor

Abstract

The invention discloses an inflection point slope adjustable double-ellipse diaphragm cavity molded line generation method and a diaphragm compressor, the method comprises the steps that a characteristic ellipse and an inflection point inclination angle are determined, and the inflection point inclination angle represents an inclination angle of a connection point of a molded line segment L1 and a molded line segment L2 in an X 'O' Y 'coordinate system; any point P on the characteristic ellipse and a characteristic point Q on the characteristic ellipse are determined, the Q point is an overrunning point, the P point is a chasing point, and therefore an elliptical segment PQ of a fixed inflection point slope inclination angle under the characteristic ellipse is determined; solving any chasing point P on the characteristic ellipse and a corresponding surpassing point Q, obtaining all molded line segment PQ elliptical line clusters under the characteristic inflection point dip angle, and obtaining the radius and deflection range of a film cavity molded line enclosed by the PQ elliptical line clusters; and two different sections of PQ elliptic molded lines L1 and L2 are combined and connected to form a complete diaphragm cavity molded line L of the diaphragm compressor, so that the requirements of the diaphragm cavity molded line of the diaphragm compressor are met. Through multi-parameter optimization design, the service life of the diaphragm is prolonged, and the reliability of the whole machine is improved.

Description

Technical Field

[0001] The invention relates to the technical field of diaphragm compressors, and in particular to a method for generating a double elliptical diaphragm cavity profile with adjustable inflection point slope and a diaphragm compressor. Background Art

[0002] The diaphragm compressor is a positive displacement compressor that uses a diaphragm to separate the oil side and the gas side. Its working principle is: the motor drives the crankshaft connecting rod to drive the piston to perform reciprocating motion to increase and release the pressure of the high-pressure oil, and then the high-pressure oil pushes the diaphragm to achieve gas compression and discharge. Due to its good sealing and large pressure ratio, diaphragm compressors are widely used in the hydrogen energy industry, especially hydrogen refueling stations are one of its important usage scenarios, and the diaphragm life, volumetric efficiency and diaphragm head strength issues are very critical and difficult to solve in the research and development of diaphragm compressors. The diaphragm is a key component in the stable operation of the diaphragm compressor, and its working performance directly affects the reliability of the compressor operation. In the process of diaphragm damage, the main forms of damage are collapse, distortion, wear and cracks, and mechanical fatigue. The damage of the diaphragm will cause its mechanical properties to be destroyed, and severe cases will even cause large economic losses.

[0003] At present, the diaphragm compressor diaphragm cavity profile widely used in China is the single-exponential small deflection diaphragm cavity profile. After long-term practice and verification, it has good reliability and practical basis. However, in the process of developing and designing new diaphragm compressor models, the traditional single-exponential diaphragm cavity profile is adjusted by three profile variables: diaphragm cavity radius, single exponent and maximum deflection. The profile optimization range is limited, and it is difficult to adjust the diaphragm stress changes caused by the change in the slope of the inflection point of the diaphragm cavity profile. It cannot meet the urgent needs of the market demand for the development of diaphragm compressor technology and the development of new high-pressure and high-speed models. The multi-parameter diaphragm cavity profile optimization design is an effective way to improve the reliability of diaphragm compressors and reduce costs. Summary of the invention

[0004] The purpose of the present invention is to address the problems in the above-mentioned prior art and to provide a method for generating a double elliptical diaphragm cavity profile with adjustable inflection point slope and a diaphragm compressor, which can overcome the problems of insufficient optimization parameters, limited optimization range and difficult adjustment of the inflection point slope in traditional single exponential profile design, adapt to diversified market demands, optimize the reliability of diaphragm compressors and increase the life of the diaphragm.

[0005] In order to achieve the above object, the present invention has the following technical solutions:

[0006] In a first aspect, 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 initial inflection point inclination 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 point inclination It represents the inclination angle of the connection point of the profile segment L1 and the profile segment L2 in the X'O'Y' coordinate system;

[0008] Determine any point P on the characteristic ellipse S, the coordinates of which are given by (acosθ P ,bsinθ P ) to describe; define the characteristic point Q on the characteristic ellipse S, the coordinates are (acosθ Q ,bsinθ Q ) is described; point Q is defined as the overtaking point and point P is defined as the catching-up point, thereby determining the ellipse segment PQ with a fixed inflection point slope angle under the characteristic ellipse S;

[0009] The coordinates of the ellipse segment PQ in the XOY coordinate system are transformed to form a coordinate system X'O'Y' with point P as the origin, the direction of the tangent line Line_P at point P as the X-axis direction, and the PQ line segment located in the first quadrant of the new coordinate system; the point coordinates (x', y') of the characteristic ellipse S in the coordinate system X'O'Y' and the representation of the PQ-type line segment L1 are obtained, and the characteristic inflection point inclination angle on the characteristic ellipse S is obtained Any elliptical line segment PQ;

[0010] Solve any pursuit point P on the characteristic ellipse S and its corresponding surpassing point Q, and obtain the characteristic inflection point inclination All the line segments PQ ellipse line clusters under the membrane cavity are obtained to obtain the radius and deflection range of the membrane cavity line surrounded by the PQ ellipse line clusters;

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

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

[0013]

[0014] Wherein: 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 solution, the coordinates (acosθ P ,bsinθ P ) and the coordinates of the feature point Q on the feature ellipse S (acosθ Q ,bsinθ Q ) satisfy the following conditions:

[0016]

[0017] The counterclockwise rotation direction along the characteristic ellipse S is the positive direction. Point Q is directly in front of point P. There are two solutions for the surpassing point Q obtained by the pursuit point P and satisfying the above conditions. Take |θ Q -θ P |The smaller Q point is used as the definition of the transcendental point Q.

[0018] As a preferred solution, the steps of performing coordinate transformation on the ellipse segment PQ in the XOY coordinate system are as follows:

[0019]

[0020] Thus, the point coordinates (x', y') of the characteristic ellipse S in the new coordinate system X'O'Y' are obtained, and the PQ-type line segment L1 is described by the following formula:

[0021] L1=[x'(θ),y'(θ)]θ∈(θ P ,θ Q )

[0022] Thus, the characteristic inflection point inclination angle on the characteristic ellipse S is obtained An arbitrary elliptical line segment PQ.

[0023] As a preferred solution, 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 cluster 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 solution, according to the design requirements of the diaphragm compressor diaphragm head profile, the two different PQ elliptical profiles L1 and L2 are combined and connected to form a complete diaphragm compressor diaphragm cavity profile L, and the solution is performed according to the following formula:

[0030]

[0031] Where: D represents the derivative operation; R maxIt is the maximum radius of the diaphragm compressor diaphragm cavity profile L after the combination, which is defined as the sum of the RA lengths of the two PQ elliptical profiles L1 and L2.

[0032] As a preferred solution, the double elliptical membrane cavity profile is expressed as follows:

[0033]

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

[0035]

[0036] Where: R L k represents the radius of the diaphragm cavity of the diaphragm compressor after assembly; P It represents the inclination slope of the inflection point P connecting the L1-type line segment and the L2-type line segment in the diaphragm compressor diaphragm cavity line L after the combination in the X'O'Y' coordinate system.

[0037] As a preferred solution, it also includes performing a diaphragm surface stress analysis on the diaphragm compressor using the combined diaphragm compressor diaphragm cavity profile L to check whether it meets the diaphragm allowable stress requirements. If not, the design is optimized or redesigned by adjusting the inflection point slope.

[0038] As a preferred solution, the maximum and minimum surface stresses of the diaphragm compressor diaphragm cavity profile L of the combined diaphragm compressor when deformed close to the diaphragm cavity profile are calculated according to 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] Where 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 integral operation; d represents differential operation; σ Pr is the radial normal stress of the diaphragm; σ Pt is the circumferential normal stress of the diaphragm; Mr is the radial shear stress of the diaphragm; Mr is the circumferential shear stress of the diaphragm; min is the minimum stress on the diaphragm surface; δmax is the maximum stress on the diaphragm surface.

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

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

[0045] The method for generating a double ellipse membrane cavity profile with adjustable inflection point slope of the present invention can generate a combined membrane cavity profile with controllable connection inflection points, which satisfies the curved surface conditions required for the membrane cavity profile of a diaphragm compressor, and has an ellipse major axis length a, a minor axis length b, an inflection point inclination angle Membrane cavity radius R L , membrane cavity deflection H L 、The characteristic angle of the profile line is θ P Multiple design parameters such as optional profile curve clusters, and inflection point inclination The adjustable feature can overcome the problems of insufficient optimization parameters, limited optimization range, and difficult adjustment of the inflection point slope in the traditional diaphragm cavity profile design, which is conducive to optimizing the design of the diaphragm cavity profile inflection point profile slope change range and optimizing the diaphragm surface stress distribution, making the profile design more flexible and more adaptable to changing design conditions and market demands. The multi-parameter optimization design is conducive to improving the diaphragm compressor diaphragm life and the reliability of the whole machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

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

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

[0050] Figure 4 This is a curve diagram showing the variation of the maximum radius of the characteristic elliptical line cluster with the characteristic angle for controlling the inflection point slope in Example 1 of the present invention;

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

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

[0053] Figure 7 It is a schematic diagram of the double ellipse membrane cavity profile with maximum deflection under the characteristic ellipse and characteristic inflection point slope conditions of Example 1 of the present invention;

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

[0055] Fig. 9 This is a curve diagram of the maximum and minimum stress changes along the radial direction on the surface of the diaphragm compressor of Example 2 of the present invention.

[0056] Icons: XOY - feature ellipse generation coordinate system; S - feature ellipse; P - a point on the feature ellipse, defined as the catch-up point; Q - a point on the feature ellipse, defined as the surpassing point; Line_P - the tangent line of the feature ellipse at point P; Line_Q - the tangent line of the feature ellipse at point Q; Angle with 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 inclination angle of the point in the XOY coordinate system; The inclination angle of point in XOY coordinate system; D1-the distance of point P from Line_Q; D2-the distance of point Q from Line_P; L1-the first ellipse line; L2-the second ellipse line; X'O'Y'-the coordinate system with point P as the origin and D1 as the horizontal coordinate; PQ line cluster-the set of ellipse segment line clusters after coordinate transformation under the slope of the characteristic ellipse feature inflection point; A1-the first type of line composition from the line segments in area A of PQ line cluster; B1-the second type of line composition from the line segments in area B of PQ line cluster A type of line composition; A2-a second type of line composition from the type line segments in the A region of the PQ line cluster; B2-a second type of line composition from the type line segments in the B region of the PQ line cluster; A region cluster-the portion of the PQ line cluster located in the first quadrant; B region 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 membrane cavity type line; HA-the D2 length of the PQ line cluster, i.e., the maximum deflection of the membrane cavity type line; θ P -The characteristic angle of the characteristic ellipse point P; H-the deflection equation of the double ellipse combined membrane cavity line. DETAILED DESCRIPTION

[0057] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] like Figure 1 to Figure 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 comprises:

[0059] Step 1: Determine the characteristic ellipse S and the initial inflection point inclination The 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 It represents the inclination angle of the connection point of the contour segment L1 and contour segment L2 in the X'O'Y' coordinate system. The characteristic ellipse S can be described by the following formula:

[0060]

[0061] Wherein: 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 characteristic ellipse S, whose coordinates can be (acosθ P ,bsinθ P ) is described, and the characteristic point Q on the characteristic ellipse S is defined, and its coordinates are given by (acosθ Q ,bsinθ Q ) and meet the following conditions:

[0063]

[0064] The counterclockwise rotation direction along the characteristic ellipse S is the positive direction. Point Q is directly in front of point P, so point Q is defined as the surpassing point, and point P is the catching-up point. There are two solutions for the surpassing point Q obtained from the catching-up point P and satisfying the above conditions. Take |θ Q -θ P The smaller Q point is used as the definition of the transcending point Q. Thus, the ellipse segment PQ with a fixed inflection point slope angle under the characteristic ellipse S is determined.

[0065] Step 3: Transform the coordinates of the ellipse segment PQ in the XOY coordinate system to form a coordinate system X'O'Y' with point P as the origin, the direction of the tangent 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] Thus, the point coordinates (x', y') of the characteristic ellipse S in the new coordinate system X'O'Y' are obtained, and 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] Thus, the characteristic inflection point inclination angle on the characteristic ellipse S is obtained An arbitrary elliptical line segment PQ.

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

[0071]

[0072] The length HA of the PQ line cluster 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] According to the design requirements of the diaphragm compressor diaphragm head profile, two different sections of PQ elliptical profiles L1 and L2 are combined and connected to form a complete diaphragm compressor diaphragm cavity profile L, which meets the general requirements of the diaphragm compressor diaphragm cavity profile, specifically described as:

[0077]

[0078] Where: D represents the derivative operation; R max It is the maximum radius of the diaphragm compressor diaphragm cavity profile L after the combination, which is defined as the sum of the RA lengths of the two PQ elliptical profiles L1 and L2.

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

[0080]

[0081] Therefore, the combined elliptical profile has the following characteristics:

[0082]

[0083] Where: R L k represents the radius of the diaphragm cavity of the diaphragm compressor after assembly; P It represents the inclination slope of the inflection point P connecting the L1-type line segment and the L2-type line segment in the diaphragm compressor diaphragm cavity line L after the combination 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 to check whether it meets the diaphragm allowable stress requirements. If not, the inflection point slope can be adjusted to optimize the design or redesign it.

[0085] The theoretical calculation formula for the maximum and minimum surface stress of the diaphragm of the diaphragm compressor using the diaphragm cavity profile of the embodiment of the present invention when deformed close to the diaphragm cavity profile is 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] Where 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 integral operation; d represents differential operation; σ Pr is the radial normal stress of the diaphragm; σ Pt is the circumferential normal stress of the diaphragm; Mr is the radial shear stress of the diaphragm; Mr is the circumferential shear stress of the diaphragm; min is the minimum stress on the diaphragm surface; δ max is the maximum stress on the diaphragm surface.

[0090] Furthermore, through the method for generating a double elliptical diaphragm cavity profile with adjustable inflection point slope according to the above-mentioned embodiment of the present invention, a combined diaphragm cavity profile with controllable connecting inflection points can be generated, which meets the surface conditions required for the diaphragm cavity profile of the diaphragm compressor, and by adjusting the inflection point slope, the stress distribution of the diaphragm cavity profile can be made more uniform, thereby reducing the unevenness of the stress distribution of the diaphragm, and improving the life of the diaphragm and the reliability of the diaphragm compressor.

[0091] The embodiment of the present invention further provides a diaphragm compressor having a diaphragm compressor diaphragm 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 a double elliptical diaphragm cavity profile of a diaphragm compressor.

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

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

[0096] Specifically, Figure 4 As shown, in the curve where the radius RA of the PQ line cluster of the characteristic ellipse S changes with the characteristic angle θ, we can see that the changing radius RA∈[15,65]mm of the curve cluster PQ.

[0097] Specifically, Figure 5 As shown, in the curve where the PQ line cluster deflection HA of the characteristic ellipse S changes with the characteristic angle θ, we can see the changing deflection HA∈[0.55,2.55]mm of the curve cluster PQ.

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

[0099] Specifically, Figure 7 As shown, the first elliptical line L1 and the second elliptical line L2 of the generated profile 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, and the membrane cavity line equation 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 profiles are connected, and the above steps can be adjusted to Adjust the profile.

[0102] Example 2

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

[0104] Specifically, the major axis length a=1000 mm and the minor axis length b=300 mm of the characteristic ellipse S are defined, and the inflection point inclination angle is defined as The elliptical line segment with the largest radius RA in the line curve cluster generated by the characteristic ellipse is selected as the first film cavity line L1 and the second film cavity line L2. The formed film cavity line is described as:

[0105]

[0106] For the convenience of stress calculation, replace L in the above profile equation with (x' L ,y' L ) to make the following coordinate changes:

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

[0108] Thus, the membrane cavity line L formed by the connection can be obtained. end like Figure 8 shown.

[0109] Specifically, for the above-mentioned membrane cavity line L end The surface stress of the diaphragm compressor is analyzed and calculated, and the surface stress distribution is as follows Fig. 9 As shown, the maximum stress of the double elliptical membrane cavity profile in this embodiment is about 175 MPa.

[0110] The embodiment of the present invention provides a method for generating a double ellipse membrane cavity profile with adjustable inflection point slope and a diaphragm compressor, which has an ellipse major axis length a, a minor axis length b, an inflection point inclination angle Membrane cavity radius R L , membrane cavity deflection H L 、The characteristic angle of the profile line is θ P Multiple design parameters such as optional profile curve clusters, and inflection point inclination The adjustable feature is conducive to optimizing the design of the inflection point of the diaphragm cavity profile, the slope change range of the profile and the stress distribution on the diaphragm surface. Compared with the traditional single-exponential diaphragm cavity profile, it has more profile design parameters, making the profile design more flexible and more adaptable to changing design conditions and market demands. The multi-parameter optimization design is conducive to improving the diaphragm life of the diaphragm compressor and the reliability of the whole machine.

[0111] Although the present application is described above with reference to specific embodiments, it should be understood by those skilled in the art that many modifications may be made to the configurations and details disclosed in the present application within the principles and scope disclosed in the present application. The scope of protection of the present application is determined by the attached claims, and the claims are intended to cover all modifications included in the equivalent literal meaning or scope of the technical features in the claims.

Claims

1. A method for generating a double elliptical membrane cavity profile with adjustable inflection point slope. It is characterized in that include: Determine the characteristic ellipse S and the initial inflection point inclination 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 point inclination It represents the inclination angle of the connection point of the profile segment L1 and the profile segment L2 in the X'O'Y' coordinate system; Determine any point P on the characteristic ellipse S, the coordinates of which are given by (acosθ P ,bsinθ P ) to describe; define the characteristic point Q on the characteristic ellipse S, the coordinates are (acosθ Q ,bsinθ Q ) is described; point Q is defined as the overtaking point and point P is defined as the catching-up point, thereby determining the ellipse segment PQ with a fixed inflection point slope angle under the characteristic ellipse S; The coordinates of the ellipse segment PQ in the XOY coordinate system are transformed to form a coordinate system X'O'Y' with point P as the origin, the direction of the tangent line Line_P at point P as the X-axis direction, and the PQ line segment located in the first quadrant of the new coordinate system; the point coordinates (x', y') of the characteristic ellipse S in the coordinate system X'O'Y' and the representation of the PQ-type line segment L1 are obtained, and the characteristic inflection point inclination angle on the characteristic ellipse S is obtained Any elliptical line segment PQ; Solve any pursuit point P on the characteristic ellipse S and its corresponding surpassing point Q, and obtain the characteristic inflection point inclination All the line segments PQ ellipse line clusters under the membrane cavity are obtained to obtain the radius and deflection range of the membrane cavity line surrounded by the PQ ellipse line clusters; According to the design requirements of the diaphragm compressor diaphragm head profile, two different sections of PQ elliptical profiles L1 and L2 are combined and connected to form a complete diaphragm compressor diaphragm cavity profile L, which meets the requirements of the diaphragm compressor diaphragm cavity profile.

2. According to the method for generating a double elliptical membrane cavity profile with adjustable inflection point slope as described in claim 1, It is characterized in that The characteristic ellipse S is described by the following formula: Wherein: 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.

3. According to the method for generating a double elliptical membrane cavity profile with adjustable inflection point slope as described in claim 2, It is characterized in that The coordinates of any point P on the characteristic ellipse S (acosθ P ,bsinθ P ) and the coordinates of the feature point Q on the feature ellipse S (acosθ Q ,bsinθ Q ) satisfy the following conditions: The counterclockwise rotation direction along the characteristic ellipse S is the positive direction. Point Q is directly in front of point P. There are two solutions for the surpassing point Q obtained by the pursuit point P and satisfying the above conditions. Take |θ Q -θ P |The smaller Q point is used as the definition of the transcendental point Q.

4. According to the method for generating a double elliptical membrane cavity profile with adjustable inflection point slope as claimed in claim 3, It is characterized in that The steps of coordinate transformation of the ellipse segment PQ in the XOY coordinate system are as follows: Thus, the point coordinates (x', y') of the characteristic ellipse S in the new coordinate system X'O'Y' are obtained, and the PQ-type line segment L1 is described by the following formula: L1=[x'(θ),y'(θ)]θ∈(θ P ,i Q ) Thus, an arbitrary elliptical line segment PQ with a characteristic inflection point inclination angle Δθ on the characteristic ellipse S is obtained.

5. According to the method for generating a double elliptical membrane cavity profile with adjustable inflection point slope as described in claim 4, It is characterized in that 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: The length HA of the PQ line cluster in the Y' direction can be described by the following formula: The radius and deflection range of the membrane cavity profile formed by the PQ elliptical line cluster are obtained:

6. The method for generating a double elliptical membrane cavity profile with adjustable inflection point slope according to claim 5, It is characterized in that According to the design requirements of the diaphragm compressor diaphragm head profile, when the two different PQ elliptical profiles L1 and L2 are combined and connected to form a complete diaphragm compressor diaphragm cavity profile L, the solution is performed according to the following formula: Where: D represents the derivative operation; R max It is the maximum radius of the diaphragm compressor diaphragm cavity profile L after the combination, which is defined as the sum of the RA lengths of the two PQ elliptical profiles L1 and L2.

7. The method for generating a double elliptical membrane cavity profile with adjustable inflection point slope according to claim 5, It is characterized in that The double elliptical membrane cavity profile expression is as follows: The combined elliptical profile has the following characteristics: Where: R L k represents the radius of the diaphragm cavity of the diaphragm compressor after assembly; P It represents the inclination slope of the inflection point P connecting the L1-type line segment and the L2-type line segment in the diaphragm compressor diaphragm cavity line L after the combination in the X'O'Y' coordinate system.

8. The method for generating a double elliptical membrane cavity profile with adjustable inflection point slope according to claim 7, It is characterized in that It also includes a diaphragm surface stress analysis of the diaphragm compressor using the combined diaphragm compressor diaphragm cavity profile L to check whether it meets the diaphragm allowable stress requirements. If not, the design is optimized or redesigned by adjusting the inflection point slope.

9. The method for generating a double elliptical membrane cavity profile with adjustable inflection point slope according to claim 8, It is characterized in that The maximum and minimum surface stresses of the diaphragm compressor diaphragm cavity profile L after the combination are calculated by the following formula when the diaphragm compressor diaphragm is deformed close to the diaphragm cavity profile: d min =min{σ Pr ±σ Mr ,s Pt ±σ Mt } d max =max{σ Pr ±σ Mr ,s Pt ±σ Mt } Where 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 integral operation; d represents differential operation; σ Pr is the radial normal stress of the diaphragm; σ Pt is the circumferential normal stress of the diaphragm; Mr is the radial shear stress of the diaphragm; Mr is the circumferential shear stress of the diaphragm; min is the minimum stress on the diaphragm surface; δ max is the maximum stress on the diaphragm surface.

10. A diaphragm compressor, It is characterized in that A diaphragm compressor diaphragm head designed according to the method for generating a double elliptical diaphragm cavity profile with adjustable inflection point slope according to any one of claims 1 to 9.

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