Valve positioner motion conversion mechanism and intelligent valve positioner

Abstract

This invention discloses a valve positioner motion conversion mechanism and an intelligent valve positioner. The valve positioner motion conversion mechanism includes a valve stem that drives the valve to open and close via up-and-down movement. A lever is disposed on the side of the valve stem, and the lever has a bearing fixed to an input shaft. A curved groove is provided in the lever, in which a lever can move. The shape of the curved groove is determined by a constant-velocity Archimedean spiral, the polar equation of which is: r = a + bθ, where: r represents the polar radius; a represents the distance from the starting point of the spiral to the center of rotation; θ represents the polar angle; and b is the increase in distance of r after each certain angle θ. The intelligent valve positioner includes a positioner housing, a potentiometer and a potentiometer gear extending from the potentiometer, an input gear, and an input shaft. It also includes a valve positioner motion conversion mechanism connecting the lever to the input shaft of the valve positioner. The structure is simple and the operation is stable.

Description

Technical Field

[0001] This invention relates to the field of valve positioner motion conversion mechanism and valve positioner technology, and in particular to a motion conversion mechanism that accurately feeds back the displacement of the valve stem to the valve positioner, and an intelligent valve positioner using such a motion conversion mechanism. Background Technology

[0002] The intelligent valve positioner converts the displacement of the valve stem into the rotation angle of the input component to determine the valve opening. The rotation angle is then converted into an electrical signal. The valve opening value determined by the input rotation angle is used to control and adjust the valve opening through the valve positioner's controller.

[0003] Figure 15 The diagram shows a mechanical linear slot motion conversion device that feeds back the valve stem displacement to the valve positioner. This device features a cylindrical lever fixed to the valve stem. The lever can be inserted into a plate with a linear slot in the center, one end of which is fixed to the input shaft. When the valve stem moves up and down, the lever moves up and down simultaneously, causing the linear slot to rotate and the input shaft at the plate's end to rotate through an angle. This converts the valve opening from the linear displacement of the valve stem into angular displacement via a mechanical transmission device. The angular displacement is then amplified several times by the transmission gears inside the valve positioner and transmitted to the potentiometer of the intelligent valve positioner. The potentiometer's rotation generates a resistance change, which is converted into an electrical signal and output to the valve positioner's control mechanism. By reading the angular displacement data converted from the valve stem displacement, which represents the valve opening, the valve opening is controlled and adjusted.

[0004] Valve positioners using this type of conversion device have a relatively simple structure, but the valve stem stroke and corresponding rotation angle cannot form a linear correspondence. As a result, the rotation angle change cannot accurately reflect the valve stem stroke and valve opening. Taking a linear slot-type conversion device with a valve stem stroke of 100mm and a rotation angle of 90° corresponding to the full stroke as an example, calculating and examining the input shaft rotation angle every 5mm from the starting point of the valve stem stroke reveals that the valve stem displacement and the resulting input shaft rotation angle are not linearly related but rather form a non-linear curve. This fails to accurately reflect the relationship between the valve stem stroke and the valve opening, affecting the working accuracy of valve positioners using this displacement-angle conversion device. To improve the accuracy of valve positioners, it is necessary to correct the data imported into such devices through a correction program based on experience and extensive experimental work, resulting in complex equipment structures and high usage and maintenance costs. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a motion conversion mechanism that enables the valve stem displacement to have a linear relationship with the input angle of the valve positioner, and an intelligent valve positioner using the motion conversion mechanism.

[0006] The first embodiment of the valve positioner motion conversion mechanism of the present invention adopts the following technical solution: It includes a valve stem, which acts as a valve component and drives the valve to open and close by moving up and down. A lever perpendicular to the valve stem axis and a lever plate forming a kinematic pair with the lever are provided on the side of the valve stem. The lever plate has a bearing fixed to an input shaft. A curved groove is provided in the lever plate, in which the lever can move. The shape of the curved groove is determined by a constant-velocity Archimedean spiral. Moving the lever radially upward from the Archimedean spiral on the lever plate surface forms a first surface perpendicular to the lever plate surface. Moving the lever radially downward from the Archimedean spiral on the lever plate surface forms a second surface perpendicular to the lever plate surface and parallel to the first surface. When the lever is at the lower dead center of the curved groove, the lever axis is the starting point of the Archimedean spiral; when the lever is at the upper dead center of the curved groove, the lever axis is the ending point of the Archimedean spiral. The bearing fixed to the lever plate surface at one end of the curved groove. The polar coordinate equation of the Archimedean spiral is:

[0007] r = a + bθ,

[0008] Where: r represents the polar radius; a represents the distance from the starting point of the helix to the center of rotation of the helix; θ represents the polar angle; and b is the distance that r increases by after each certain angle θ.

[0009] In a preferred embodiment of the valve positioner motion conversion mechanism of the present invention, when the lower dead center of the curved groove shape coincides with the axis of the bearing seat, a=0, and the polar coordinate equation of the Archimedean spiral is:

[0010] r = bθ.

[0011] Furthermore, the maximum stroke of the valve stem is the maximum length of the extreme diameter r, the maximum stroke range of the valve stem is 25mm-150mm, the rotation angle β corresponding to the maximum stroke of the valve stem is 90°, and the value range of b is 25 / 90-150 / 90.

[0012] Furthermore, the maximum stroke of the valve stem is 25mm, 50mm, 100mm, and 150mm, respectively, and the rotation angle β corresponding to the maximum stroke of the valve stem is 90°, with b values ​​of 25 / 90, 50 / 90, 100 / 90, and 150 / 90, respectively.

[0013] In a preferred embodiment of the valve positioner motion conversion mechanism of the present invention, the lower dead point and upper dead point sides between the mutually parallel first and second surfaces of the curved groove are respectively connected by arc end faces.

[0014] The second embodiment of the valve positioner motion conversion mechanism of the present invention adopts a technical solution that includes a valve stem, which serves as a valve component and drives the valve to open and close by moving up and down. A lever perpendicular to the valve stem axis and a lever plate forming a kinematic pair with the lever are provided on the side of the valve stem. The lever plate has a bearing fixed to an input shaft. A curved groove is provided in the lever plate, in which the lever can move. The shape of the curved groove is an arc formed by a mirror line connecting a constant-velocity Archimedean spiral through a mirror symmetry axis perpendicular to the origin of the Archimedean spiral. The curve is determined such that, moving the lever upwards along the arc-shaped curve on the paddle surface forms a first surface perpendicular to the paddle surface; moving the lever downwards along the arc-shaped curve on the paddle surface forms a second surface perpendicular to the paddle surface and parallel to the first surface. When the lever is at the lower endpoint of the curved groove, the lever axis is the starting point of the arc-shaped curve; when the lever is at the upper endpoint of the curved groove, the lever axis is the ending point of the arc-shaped curve. The bearing is fixed to the paddle surface in the middle of the curved groove. The polar coordinate equation of the Archimedean spiral is:

[0015] r = a + bθ,

[0016] Where: r represents the polar radius; a represents the distance from the starting point of the helix to the center of rotation of the helix; θ represents the polar angle; and b is the distance that r increases by after each certain angle θ.

[0017] In a preferred embodiment of the valve positioner motion conversion mechanism of the present invention, when the lower dead center of the curved groove shape coincides with the axis of the bearing seat, a=0, and the polar coordinate equation of the Archimedean spiral is:

[0018] r = bθ.

[0019] Furthermore, the maximum stroke of the valve stem is twice the maximum length of the extreme diameter r, the maximum stroke range of the valve stem is 25mm-150mm, the rotation angle β corresponding to the maximum stroke of the valve stem is 90°, and the value range of b is 25 / 90-150 / 90.

[0020] In a preferred embodiment of the valve positioner motion conversion mechanism of the present invention, the lower dead point and upper dead point sides between the mutually parallel first and second surfaces of the curved groove are respectively connected by arc end faces.

[0021] The technical solution of the intelligent valve positioner of the present invention includes a positioner housing, a potentiometer fixed inside the positioner housing, a potentiometer gear extending from the potentiometer, an input gear meshing with the potentiometer gear, and an input shaft integrally extended to the outside with the input gear. It also includes a motion conversion mechanism whose paddle is connected to the input shaft of the valve positioner.

[0022] Compared with existing technologies, the present invention has the following advantages: The valve positioner motion conversion mechanism determines the surface shape of the curved groove using a constant-speed Archimedean spiral. Regardless of whether the curved groove surface is determined by the curve trajectory of the first or second embodiment, ignoring errors caused by factors such as machining precision or minute gaps between the lever and the groove, when the valve stem and lever move up and down, the lever and the curved groove surface rotate relative to each other from the lower dead point to the upper dead point. Throughout the entire valve stem stroke, the lever drives the input shaft to rotate, proportionally converting the linear displacement of the valve stem into angular displacement and transmitting it to the input shaft. This valve positioner motion conversion mechanism has a simple structure and stable operation. The input shaft rotation angle accurately reflects the relationship between the valve stem stroke and the valve opening, ensuring the accuracy of the intelligent valve positioner without the need for secondary correction of the input rotation angle data. Attached Figure Description

[0023] Figure 1 This is a front view schematic diagram of the valve positioner motion conversion mechanism according to the first embodiment;

[0024] Figure 2 yes Figure 1 A partial sectional view of the left side;

[0025] Figure 3 This is a schematic diagram showing the relative positions of the paddle, lever, and bearing in one implementation method.

[0026] Figure 4 This is a schematic diagram showing the relative positions of the paddle, lever, and bearing in another implementation method;

[0027] Figure 5 yes Figure 3 A schematic diagram of the Archimedean spiral used by the center paddle to determine the shape of the curved groove.

[0028] Figure 6 yes Figure 4 A schematic diagram of the Archimedean spiral used by the center paddle to determine the shape of the curved groove.

[0029] Figure 7 This is a trend diagram showing the variation of valve stem displacement and input shaft rotation angle in the Archimedes spiral-to-linear motion conversion mechanism.

[0030] Figure 8 This is a front view schematic diagram of the valve positioner motion conversion mechanism in the second embodiment;

[0031] Figure 9 yes Figure 8 A partial sectional view of the left side;

[0032] Figure 10 This is a schematic diagram showing the relative positions of the paddle, lever, and bearing in one implementation method.

[0033] Figure 11 This is a schematic diagram showing the relative positions of the paddle, lever, and bearing in another implementation method;

[0034] Figure 12 yes Figure 9 and 10 A schematic diagram of the arc curve that determines the shape of the groove on the curved surface using the center paddle;

[0035] Figure 13 This is a schematic diagram of the intelligent valve positioner structure according to the first embodiment;

[0036] Figure 14 This is a schematic diagram of the intelligent valve positioner structure according to the second implementation method;

[0037] Figure 15 This is a schematic diagram of the motion conversion mechanism of a linear slot valve positioner in existing technology.

[0038] The labels in the diagram represent: 1-valve stem, 2-lever, 3-paddle, 4-curved groove, 5-shaft seat, 6-Archimedean spiral, 7-arc curve, 8-mirror symmetry axis, 9-valve positioner, 10-motion conversion mechanism, 31-set screw, 41-first surface, 42-second surface, 43-circular end face, 44-bottom dead center, 45-top dead center, 51-shaft seat axis, 91-positioner housing, 92-potentiometer, 93-potentiometer gear, 94-input gear, 95-input shaft. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0040] Please see Figure 1-6 As shown, the valve positioner motion conversion mechanism of the first embodiment of the present invention includes a valve stem 1 that drives the valve to open and close as a valve component. A lever 2 perpendicular to the valve stem axis and a lever 3 forming a motion pair with the lever are provided on the side of the valve stem. A bearing 5 fixed to the input shaft 95 is provided on the lever. The bearing 5 of the lever is fixed to the input shaft 95 by a set screw 31. A curved groove 4 is provided in the lever in which the lever can move.

[0041] The shape of the curved groove is determined by a constant-velocity Archimedean spiral 6, whose polar equation is: r = a + bθ, where: r represents the polar radius; a represents the distance from the starting point of the spiral to the center of rotation of the spiral; θ represents the polar angle; and b is the increase in distance of r after each certain angle θ. When the lower dead center 44 of the curved groove shape coincides with the axis 51 of the bearing seat, a = 0, and the polar equation of the Archimedean spiral is: r = bθ. When the valve stem moves up and down, the lever moves from the lower dead center to the upper dead center of the curved groove by relative rotation with the surface of the curved groove. Within the entire stroke range of the valve stem, the lever drives the input shaft to rotate, converting the linear displacement of the valve stem into angular displacement proportionally and transmitting it to the input shaft.

[0042] A first surface 41, perpendicular to the paddle surface, is formed by moving the lever upwards along the Archimedean spiral. A second surface 42, perpendicular to the paddle surface and parallel to the first surface, is formed by moving the lever downwards along the Archimedean spiral. When the lever is at the lower stop 44 of the curved groove, the lever axis is the starting point of the Archimedean spiral; when the lever is at the upper stop 45 of the curved groove, the lever axis is the ending point of the Archimedean spiral. The lower stop 44 and upper stop 45 sides of the parallel first and second surfaces of the curved groove can be connected by arc-shaped end faces 43. The bearing is fixed to the paddle surface at one end of the curved groove.

[0043] In this embodiment, the maximum stroke of the valve stem is the maximum length of the extreme diameter r. The maximum stroke range of the valve stem can be 25mm-150mm, and the corresponding rotation angle β is 90°. The value of b ranges from 25 / 90 to 150 / 90. Preferably, the maximum stroke of the valve stem is 25mm, 50mm, 100mm, and 150mm, the corresponding rotation angle β is 90°, and the b values ​​are 25 / 90, 50 / 90, 100 / 90, and 150 / 90, respectively.

[0044] Please see Figure 7 As shown, in one embodiment of the valve positioner motion conversion mechanism of the first embodiment of the present invention, the curve of the change of the valve stem stroke corresponding to the rotation angle θ when the maximum stroke of the valve stem is 100mm, the rotation angle corresponding to the full stroke is 90°, a=0, and b=5mm is as follows: Figure 7 The trend line A, the curved groove defined by the Archimedean spiral, whether defined by one or multiple Archimedean spirals, and regardless of whether the constant a is zero or greater than zero, exhibits a linear change in the angle of rotation relative to the valve stem stroke (i.e., the polar axis). The comparative example is a prior art linear groove type conversion device, with a maximum valve stem stroke of 100mm and a full stroke corresponding to a 90° rotation angle. The curve showing the change in the rotation angle corresponding to the valve stem stroke is as follows. Figure 7In trend B, there is a certain deviation between the corresponding points of the two trend lines, with a maximum offset of 4.07 degrees. During operation, after being amplified by the internal transmission gears of the valve positioner (usually by 3 times), the maximum error may reach about 12 degrees.

[0045] Please see Figure 8-12 As shown, the valve positioner motion conversion mechanism of the second embodiment of the present invention includes a valve stem 1, which acts as a valve component and drives the valve to open and close by moving up and down. A lever 2 perpendicular to the valve stem axis and a lever 3 forming a kinematic pair with the lever are provided on the side of the valve stem. The lever 3 has a bearing 5 fixed to an input shaft. A curved groove 4 is provided in the lever 3, in which the lever can move. The shape of the curved groove is determined by an arc curve 7 formed by a mirror line of a constant-velocity Archimedean spiral connected to a mirror axis of symmetry 8 perpendicular to the origin of the Archimedean spiral. The polar equation of the Archimedean spiral is: r = a + bθ, where: r represents the polar radius; a represents the distance from the starting point of the spiral to the center of rotation; θ represents the polar angle; and b is the increase in distance of r after passing a certain angle θ. When the arc curve is coaxial with the input shaft axis, a = 0, and the polar equation of the Archimedean spiral is: r = bθ.

[0046] A first surface 41, perpendicular to the paddle surface, is formed by moving the paddle lever upwards along the arc curve. A second surface 42, perpendicular to the paddle surface and parallel to the first surface, is formed by moving the paddle lever downwards along the arc curve. When the paddle lever is at the lower stop 44 of the curved groove, its axis is the starting point of the arc curve. When the paddle lever is at the upper stop 45 of the curved groove, its axis is the ending point of the arc curve. The lower stop 44 and upper stop 45 sides of the parallel first and second surfaces of the curved groove can be connected by arc-shaped end faces 43. The bearing is fixed to the paddle surface in the middle of the curved groove.

[0047] In this embodiment, the maximum stroke of the valve stem is 25mm-150mm, and the corresponding rotation angle β is 90°. The value of b ranges from 25 / 90 to 150 / 90. The arc curve is divided into two segments with the mirror symmetry axis 8 as the dividing point. The valve stem stroke corresponding to each segment is 1 / 2 of the maximum valve stem stroke, and the corresponding rotation angle is 1 / 2β, which is 45°.

[0048] Please see Figure 13-14As shown, one embodiment of the intelligent valve positioner includes a positioner housing 91, a potentiometer 92 fixed inside the positioner housing, a potentiometer gear 93 extending from the potentiometer, an input gear 94 meshing with the potentiometer gear, and an input shaft 95 integrally extended to the outside with the input gear. It also includes a motion conversion mechanism 10 whose shape is determined by a curved groove 6, or whose shape is determined by a curved groove 6, or whose shape is determined by an arc curve 7 formed by a mirror line of a mirror symmetry axis 8 perpendicular to the origin of the Archimedean spiral.

[0049] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A valve positioner motion conversion mechanism, comprising a valve stem (1) for driving a valve to open and close through up and down motion as a valve component, a push rod (2) arranged on the side of the valve stem and perpendicular to the axis of the valve stem, and a push piece (3) forming a kinematic pair with the push rod, wherein an axle seat (5) fixed with an input shaft (95) is arranged on the push piece, and the axle seat (5) is fixed with the input shaft (95) through a jackscrew (31), characterized in that, The curved slot (4) in which the plunger can move is arranged in the dial piece, the shape of the curved slot is determined by an equi-speed ratio Archimedes spiral line (6), the first surface (41) perpendicular to the surface of the dial piece is formed by moving the plunger radius distance upward from the Archimedes spiral line on the surface of the dial piece, the second surface (42) perpendicular to the surface of the dial piece and parallel to the first surface is formed by moving the plunger radius distance downward from the Archimedes spiral line on the surface of the dial piece, the plunger axis is the start point of the Archimedes spiral line when the plunger is located at the lower dead point (44) of the curved slot, the plunger axis is the end point of the Archimedes spiral line when the plunger is located at the upper dead point (45) of the curved slot, the shaft seat is fixed on the surface of the dial piece at one end of the curved slot, the polar coordinate equation of the Archimedes spiral line is: r = a + bθ, wherein: r represents the polar radius; a represents the distance from the start point of the spiral line to the rotation center of the spiral line; θ represents the polar angle; b is the distance increased by r after a certain angle θ; a = 0 when the lower dead point (44) of the curved slot shape is determined to coincide with the shaft center line (51) of the shaft seat, the polar coordinate equation of the Archimedes spiral line is: r = bθ.

2. The valve positioner motion conversion mechanism of claim 1, wherein, The maximum stroke of the valve stem up and down movement is the maximum length of the polar radius r, the maximum stroke range of the valve stem is 25mm-150mm, the maximum stroke of the valve stem corresponds to the rotation angle β of 90°, and the value range of b is 25 / 90-150 / 90.

3. The valve positioner motion conversion mechanism of claim 2, wherein, The maximum stroke of the valve stem is respectively 25mm, 50mm, 100mm and 150mm, the maximum stroke of the valve stem corresponds to the rotation angle β of 90°, and the value of b is respectively 25 / 90, 50 / 90, 100 / 90 and 150 / 90.

4. The valve positioner motion conversion mechanism of claim 3, wherein, The lower dead point (44) and the upper dead point (45) between the mutually parallel first surface and the second surface of the curved slot are respectively connected with the circular arc end face (43).

5. A valve positioner motion conversion mechanism, comprising a valve stem (1) for driving a valve to open and close through up and down motion as a valve component, a push rod (2) perpendicular to the axis of the valve stem arranged on the side of the valve stem, and a push piece (3) forming a kinematic pair with the push rod, the push piece being provided with an axle seat (5) fixed with an input shaft, characterized in that, The curved slot (4) in which the plunger can move is arranged in the dial piece, the shape of the curved slot is determined by an equi-speed ratio Archimedes spiral line through the mirror image line (7) connected by the mirror image symmetry axis (8) of the Archimedes spiral line, the first surface (41) perpendicular to the surface of the dial piece is formed by moving the plunger radius distance upward from the arc-shaped curve on the surface of the dial piece, the second surface (42) perpendicular to the surface of the dial piece and parallel to the first surface is formed by moving the plunger radius distance downward from the arc-shaped curve on the surface of the dial piece, the plunger axis is the start point of the arc-shaped curve when the plunger is located at the lower dead point (44) of the curved slot, the plunger axis is the end point of the arc-shaped curve when the plunger is located at the upper dead point (45) of the curved slot, the shaft seat is fixed on the surface of the dial piece in the middle of the curved slot, the polar coordinate equation of the Archimedes spiral line is: r = a + bθ, wherein: r represents the polar radius; a represents the distance from the start point of the spiral line to the rotation center of the spiral line; θ represents the polar angle; b is the distance increased by r after a certain angle θ; a = 0 when the midpoint of the curved slot shape is determined to coincide with the shaft center line of the shaft seat, the polar coordinate equation of the Archimedes spiral line is: r = bθ.

6. The valve positioner motion conversion mechanism of claim 5, wherein, The maximum stroke of the up-and-down movement of the valve stem is twice the maximum length of the polar radius r, the maximum stroke of the valve stem ranges from 25 mm to 150 mm, the corresponding rotation angle β of the maximum stroke of the valve stem is 90°, and the value range of b is 25 / 90-150 / 90.

7. The valve positioner motion conversion mechanism of claim 6, wherein, The lower dead point (44) and the upper dead point (45) between the mutually parallel first surface and the second surface of the curved surface notch are connected by a circular arc end surface (43) respectively.

8. An intelligent valve positioner comprising a positioner housing (91), a potentiometer (92) fixed in the positioner housing and a potentiometer gear (93) extending from the potentiometer, an input gear (94) engaging the potentiometer gear, and an input shaft (95) extending integrally with the input gear to the outside, characterized in that The valve positioner motion conversion mechanism (10) of any one of claims 1-7, wherein the motion conversion mechanism is connected to the input shaft of the valve positioner (9) through a dial.

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