Control valve positioner mounting structure and control valve

Abstract

To provide a control valve positioner mounting structure and a control valve that allow for easy adjustment of the connection position of the feedback lever to the valve stem with a simple configuration. [Solution] The positioner mounting structure 60 and the control valve 1 of the control valve are configured such that the feedback lever 52 of the positioner 50 is connected to the valve shaft 20 of the control valve 1 via a connecting member 53 so as to be able to swing around the rotation axis in accordance with the operation of the valve shaft 20 of the control valve 1. The positioner mounting structure 60 and the control valve 1 have a lever adjustment connecting member 70 that is fixed to a predetermined position on the valve shaft 20 and fixes the connecting member 53 so as to be able to adjust the direction of the swing of the feedback lever 52.

Description

TECHNICAL FIELD

[0001] The present invention relates to a positioner mounting structure for a control valve, in which a feedback lever of the positioner is swingably connected to a valve shaft in accordance with the operation of the valve shaft of the control valve via a connecting pin passed through an elongated hole of the feedback lever, and to a control valve. BACKGROUND ART

[0002] Conventionally, control valves used for process control of flow rates in chemical plants and the like use positioners as devices for controlling the valve opening degree. The positioner calculates a deviation between a set value of the valve opening degree of the control valve instructed from a host device and an actually measured value of the valve opening degree of the control valve, and sends a control signal generated based on the deviation as an air signal to an air actuator or the like of the control valve, thereby controlling the valve opening degree of the control valve. The positioner has, for example, a feedback lever connected to the valve shaft of the control valve, and calculates the actually measured value of the valve opening degree from the angle of the feedback lever that swings in accordance with the operation of the valve shaft.

[0003] The positioner is mounted near the valve shaft in order to connect the feedback lever to the valve shaft. The positioner converts the linear motion of the valve shaft into rotational motion to detect the valve opening degree, and in order to improve the detection accuracy, it is necessary to adjust the feedback lever to be perpendicular to the valve shaft at the intermediate position of the valve opening degree, that is, at the intermediate position of the stroke of the valve shaft. To adjust the feedback lever to be perpendicular to the valve shaft at the intermediate position of the stem stroke, there is a method of adjusting the mounting position of the positioner. However, since the positioner is heavy and difficult to handle, the position adjustment work is complicated, and various positioner mounting structures for control valves for easier adjustment have been proposed.

[0004] For example, Patent Document 1 describes a valve positioner in which a pin that engages with an elongated hole in a feedback lever is provided on a rotating member that is rotatably supported on a slide base that is movable relative to the valve stem (valve shaft), and the axis of rotation of this rotating member and the axis of the pin are different. This valve positioner is designed so that the valve positioner is fixed in a predetermined position, the slide base is roughly adjusted and fixed using the elongated hole with the pin fixed in the elongated hole, and then the feedback lever can be finely adjusted by rotating the rotating member to make the feedback lever perpendicular to the valve stem (valve shaft). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Publication No. 61-032686 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, in the valve positioner described in Patent Document 1, when adjusting the feedback lever to be perpendicular to the valve stem, it is necessary to first adjust the position of the slide base relative to the valve stem and fix it with a fixing bolt, and then rotate the rotating member to make fine adjustments. In other words, the valve positioner described in Patent Document 1 adjusts the feedback lever to be perpendicular to the valve stem by adjusting and fixing two points. Therefore, the valve positioner described in Patent Document 1 requires a two-step adjustment process when adjusting the feedback lever to be perpendicular to the valve stem. Moreover, if the rough adjustment using the slide base in the first step is not performed properly, the fine adjustment using the rotating member in the second step may not work well, potentially resulting in the need to redo the rough adjustment using the slide base in the first step. Furthermore, because two adjustment points must be provided to correspond to rough and fine adjustments, the connection configuration between the feedback lever and the valve stem becomes complex.

[0007] The present invention was developed to solve the problems of the prior art, and its objective is to provide a control valve positioner mounting structure and a control valve that can easily adjust the connection position of the feedback lever to the valve stem with a simple configuration. [Means for solving the problem]

[0008] To achieve the above objective, the invention according to claim 1 is a mounting structure for a control valve positioner in which a feedback lever of the positioner is connected to the valve shaft of the control valve via a connecting member so as to be able to swing about a rotational shaft in accordance with the operation of the valve shaft of the control valve, the mounting structure for a control valve positioner having a lever adjustment connecting member that is fixed at a predetermined position on the valve shaft and fixes the connecting member so as to be able to adjust the direction of the swing of the feedback lever.

[0009] The invention according to claim 2 is a positioner mounting structure in which the lever adjustment connecting member is configured to allow both a movable state in which the connecting member can move along the stroke direction of the valve shaft relative to the lever adjustment connecting member, and a fixed state in which it is fixed in an adjusted position, wherein in the movable state the direction of the swing of the feedback lever can be adjusted, and in the fixed state the feedback lever can swing freely in accordance with the movement of the valve shaft.

[0010] The invention according to claim 3 is a mounting structure for a control valve positioner in which the connecting member is fixed to the lever adjustment connecting member at a position closer to the positioner than the valve stem in the direction perpendicular to the valve stem.

[0011] The invention according to claim 4 is a mounting structure for a control valve positioner, wherein the lever adjustment connecting member is a plate-shaped member and comprises a valve shaft fixing plate portion fixed in a position that overlaps the valve shaft when viewed from the radial direction of the valve shaft, and a connecting member fixing plate portion provided wider in the stroke direction of the valve shaft than the valve shaft fixing plate portion, for adjusting and fixing the position of the connecting member in the stroke direction.

[0012] The invention according to claim 5 is a mounting structure for a control valve positioner having a fixing member fixed to the valve shaft, wherein a lever adjustment connecting member is fixed to the valve shaft via the fixing member.

[0013] The invention according to claim 6 is a mounting structure for a control valve positioner in which a lever adjustment connecting member is formed, and a connecting member fixing groove is formed that extends parallel and linearly in the stroke direction, allowing an amount of adjustment for the fixing position of the connecting member in the stroke direction of the valve shaft.

[0014] The invention according to claim 7 is a mounting structure for a control valve positioner in which the lever adjustment connecting member expands the adjustment range of the fixing position of the connecting pin to correspond to multiple stroke widths of different control valves.

[0015] The invention according to claim 8 is a control valve provided with the mounting structure for the positioner of the control valve described in claim 1. [Effects of the Invention]

[0016] According to the invention of claim 1, by having a lever adjustment connecting member that is fixed to a predetermined position on the valve stem of the control valve and fixes the connecting member so as to be able to adjust the direction of the swing of the feedback lever, when connecting the feedback lever of the positioner to the valve stem via the connecting member, the connecting member is fixed while being adjusted so that the direction of the swing of the feedback lever is perpendicular to the valve stem at the center position of the stroke of the valve stem, so that the direction of the swing of the feedback lever can be adjusted in conjunction with the work of fixing the connecting member to the lever adjustment connecting member. Furthermore, the point for adjusting the direction of the feedback lever's swing and the point for fixing the connecting member to the lever adjustment connecting member can be integrated into a single location. Therefore, a simple configuration allows for easy adjustment of the connection position of the feedback lever to the valve stem.

[0017] According to the invention of claim 2, the lever adjustment connecting member is configured to be able to move along the stroke direction of the valve shaft relative to the lever adjustment connecting member, and to be fixed in a position adjusted in the stroke direction. In the movable state, the direction of the swing of the feedback lever can be adjusted, and in the fixed state, the feedback lever can swing freely in accordance with the movement of the valve shaft. Therefore, the connection position of the feedback lever with respect to the valve shaft can be adjusted by a series of operations of moving the connecting member in the stroke direction relative to the lever adjustment connecting member and fixing it.

[0018] According to the invention of claim 3, the connecting member is fixed to the lever adjustment connecting member at a position closer to the positioner than the valve stem in a direction perpendicular to the valve stem. This allows the connecting member to be fixed to the lever adjustment connecting member while adjusting its position to avoid interference with the valve stem, and as a result, the connection position of the feedback lever with respect to the valve stem can be easily adjusted. Furthermore, because the feedback lever rotates around the rotation axis, the range of oscillation can be kept smaller at the position of the lever adjustment connecting member than at the position of the valve stem. Therefore, by fixing the connecting member to the lever adjustment connecting member at a position closer to the positioner, the adjustment range can be made much smaller than if the direction of oscillation of the feedback lever were adjusted at the position of the valve stem.

[0019] According to the invention of claim 4, the lever adjustment connecting member is a plate-shaped member and has a valve stem fixing plate portion fixed in a position that overlaps the valve stem when viewed from the radial direction of the valve stem, and a connecting member fixing plate portion that is wider in the stroke direction of the valve stem than the valve stem fixing plate portion and adjusts and fixes the connecting member in the stroke direction. This makes it possible to reduce material costs and weight while expanding the range in which the direction of the oscillation of the feedback lever can be adjusted in a position that is less likely to interfere with the valve stem.

[0020] According to the invention of claim 5, a fixing member fixed at a predetermined position of the valve stem is provided, and the lever adjustment connecting member is fixed to the valve stem via the fixing member, so that the fixing member can be provided with additional functions such as an indicator pointer, and the lever adjustment connecting member can have a simple configuration focused only on the position adjustment function of the feedback lever.

[0021] According to the invention of claim 6, the lever adjustment connecting member is formed with a connecting member fixing groove that extends linearly parallel to the stroke direction while allowing the adjustment amount of the fixing position of the connecting member in the stroke direction of the valve stem, so that the connecting member is slid along the connecting member fixing groove to adjust the direction of the swing of the feedback lever, whereby the feedback lever can be easily adjusted and fixed in the direction orthogonal to the valve stem.

[0022] According to the invention of claim 7, the lever adjustment connecting member has an expanded adjustment range of the fixing position of the connecting member corresponding to the adjustment range assumed to be required for control valves with different stroke amounts, so that it can be made a common component that can be shared by different control valves, and as a result, the manufacturing cost can be reduced.

[0023] According to the invention of claim 8, by providing the positioner mounting structure for a control valve according to claim 1, the same effects as the positioner mounting structure for a control valve according to claim 1 are achieved. [Brief Description of the Drawings]

[0024] [Figure 1] It is a schematic configuration diagram of the control valve according to the embodiment. [Figure 2] It is a perspective view showing the vicinity of the positioner mounting structure for a control valve. [Figure 3] It is a rear view of the vicinity of the positioner mounting structure for a control valve. [Figure 4] It is an exploded perspective view showing, in an exploded manner, the connecting portion between the feedback lever of the positioner and the valve stem via the connecting member. [Figure 5]This diagram illustrates the use of a lever adjustment connecting member as a common part for different control valves. [Figure 6] This is a perspective view of the mounting plate for attaching optional parts. [Figure 7] This is a diagram illustrating the adjustment procedure for the feedback lever. [Figure 8] (a) shows the valve stem at the lower end of the stroke, (b) shows the valve stem at the center of the stroke, and (c) shows the valve stem at the upper end of the stroke. [Figure 9] This is an exploded perspective view showing a modified example of the positioner mounting structure. [Modes for carrying out the invention]

[0025] The positioner mounting structure and the embodiment of the control valve according to the present invention will be described in detail below with reference to Figures 1 to 6. This disclosure is not limited to the embodiments shown below. Furthermore, it should be noted that the drawings are schematic, and the dimensional relationships and proportions of each element may differ from reality. Additionally, there may be differences in dimensional relationships and proportions between drawings. Figure 1 is a schematic diagram of the control valve 1 according to an embodiment. Figure 2 is a perspective view showing the vicinity of the mounting structure 60 of the positioner of the control valve 1. Figure 3 is a rear view of the vicinity of the mounting structure 60 of the positioner of the control valve 1. Figure 4 is an exploded perspective view showing the connection portion between the feedback lever 52 of the positioner 50 and the valve shaft 20 via the connecting member 53. Figure 5 is a diagram illustrating the use of a lever adjustment connecting member 70 as a common part for different control valves. Figure 6 is a perspective view of the mounting plate 90 for attaching optional parts.

[0026] An embodiment of the present invention, the control valve 1, is used for process control of flow rate in a chemical plant or the like, and comprises a body 10 having a primary flow path 11 which is the fluid inlet side and a secondary flow path 12 which is the fluid outlet side formed inside; a valve body 16 which opens and closes the flow paths to connect or block the primary flow path 11 and the secondary flow path 12; a stem 21 integrally provided with the valve body 16; a drive unit 30 which drives a drive shaft 33 connected to the stem 21; an opening degree detection unit 40 provided with a positioner 50; and a bonnet 17 connected to the upper part of the body 10.

[0027] <About Body 10> The body 10 has a communication port 13 located approximately in the center that connects the primary flow path 11, which is the fluid inlet side, and the secondary flow path 12, which is the fluid outlet side. A valve seat 13a is provided at the opening edge of this communication port 13, against which the valve body 16 abuts when the valve is closed. Furthermore, a flange section is provided at the top of the body, which connects to the hood. Furthermore, flange portions 14 and 15, which are connected to piping, are provided at the inlet of the primary flow path 11 and the outlet of the secondary flow path 12 of the body 10.

[0028] <Regarding valve body 16 and stem 21> The valve body 16 and the stem 21 are integrally provided as a valve shaft, and the upper end of the stem 21 is connected to a drive shaft 33 driven by a drive unit 30, so that they move up and down together with the stem 21 in conjunction with the drive shaft 22 within a predetermined stroke width. In this embodiment, when the drive shaft 33 and the stem 21 are not distinguished, they will be referred to as the valve shaft 20.

[0029] <About the drive unit 30> In this embodiment, the drive unit 30 uses a pneumatic system. As shown in Figure 1, it has an air chamber 32 partitioned by a diaphragm 31 inside. By supplying air to this air chamber 32, the diaphragm 31 is pushed up, causing the drive shaft 33 suspended from the diaphragm 31 to rise against the elastic force of the spring 34. This method is an airless closed type that operates the valve body in the opening direction by supplying air, and is also called a reverse-acting type, but the present invention can also be applied to the reverse forward-acting type control valve. Furthermore, the drive unit 30 lowers the drive shaft by expelling air from the air chamber 32 and pushing down the diaphragm 31 with the elastic force of the spring 34. Furthermore, the drive unit is not limited to a pneumatic system; for example, an electric system may be used to raise and lower the drive shaft 33.

[0030] <About the opening degree detection unit 40> The valve opening detection unit 40 is a part that detects the valve opening using a positioner 50 fixed to a yoke 41 which is provided between the bonnet 17 and the drive unit 30 so that the raising and lowering movement of the valve stem 20 can be visually observed.

[0031] <About Positioner 50> The positioner 50 calculates the difference between the set value of the valve opening of the control valve 1 instructed from a higher-level device (not shown) and the measured value of the valve opening of the control valve 1, and controls the valve opening of the control valve 1 by outputting a control signal generated based on that difference as an air signal to the drive unit 30 of the control valve 1. The positioner 50 calculates the measured value of the valve opening from the angle of a feedback lever 52 that is connected to the valve stem 20 of the control valve 1 and swings in accordance with the movement of the valve stem 20. In this embodiment, a commercially available product is used for the positioner 50.

[0032] The positioner 50 detects the displacement of the valve stem 20 of the control valve 1 as the angle of the feedback lever 52 connected to the valve stem 20, calculates the actual valve opening value from the detected angle of the feedback lever 52, calculates the deviation between the actual value and the set value of the valve opening of the control valve 1 instructed by the higher-level device, generates an electrical signal that instructs the amount to be operated by the drive unit 30 on the drive shaft 33 based on the deviation, converts the generated electrical signal into an air signal and outputs it to the drive unit 30 to control the valve opening of the control valve 1 by operating the drive shaft 33 with an amount corresponding to the target value of the valve opening.

[0033] The positioner 50 has a main body 51 which incorporates an angle sensor (not shown), a controller (not shown) such as a microcontroller, and a feedback lever 52 which rotates around a rotation shaft 51a provided inside the main body 51. The main body of the device 51 is fixed to a predetermined position on the yoke 41 via the mounting plate 43.

[0034] The feedback lever 52 has an elongated hole 52a formed therein, and is connected to the lever adjustment connecting member 70 via a connecting member 53 that passes through this elongated hole 52a. The elongated hole 52a has a width that is approximately the same as or slightly larger than the connecting member 53, and is designed to guide the connecting member 53 to move along its longitudinal direction.

[0035] The connecting member 53 is a pin-shaped member, with an enlarged head portion 53a at one end and a screw 53b at the other end for securing the lever adjustment connecting member 70 by screwing in two nuts 54 and 55, which will be described later.

[0036] <Regarding the mounting structure 60 of the positioner> The opening degree detection unit 40 uses a mounting structure 60 for the positioner of the control valve. This mounting structure 60 for the positioner of the control valve connects the feedback lever 52 of the positioner 50 to the valve shaft 20 of the control valve 1 via a connecting member 53 so that it can swing freely in accordance with the operation of the valve shaft 20 of the control valve 1.

[0037] The mounting structure 60 for the control valve positioner includes a positioner 50 fixed to the yoke 41 and a lever adjustment connecting member 70 that fixes a connecting member 53 so as to be able to adjust the direction of the swing of the feedback lever 52 while the connecting member is fixed to a predetermined position on the valve shaft 20.

[0038] <Regarding the lever adjustment connecting member 70> The lever adjustment connecting member 70 connects the feedback lever 52 and the valve stem 20 in order to adjust the feedback lever 52 so that it is perpendicular to the valve stem 20 at an intermediate position of the valve opening, that is, at an intermediate position of the stroke of the valve stem 20.

[0039] The connecting member 53 is fixed to the lever adjustment connecting member 70 at a position closer to the positioner 50 relative to the valve stem 20 in a direction perpendicular to the valve stem 20. The lever adjustment connecting member 70 is a plate-shaped member and has a valve stem fixing plate portion 71 that is fixed in a position that overlaps the valve stem when viewed from the radial direction of the valve stem 20, and a connecting member fixing plate portion 72 that is wider in the stroke direction of the valve stem 20 than the valve stem fixing plate portion 71 and adjusts and fixes the connecting member 53 in the stroke direction of the valve stem 20. In other words, the lever adjustment connecting member 70 is made of a single plate and consists of a part that is fixed to the valve stem 20 and a part that adjusts and fixes the connecting member 53 in the stroke direction of the valve stem 20 at a position that is less likely to interfere with the valve stem 20, or more specifically, a part that adjusts the direction of the swing of the feedback lever 52 and fixes the connecting member 53 to the lever adjustment connecting member 70 at the adjusted position.

[0040] The lever adjustment connecting member 70 has a connecting member fixing groove 72a that extends parallel and linearly in the stroke direction, allowing for adjustment of the fixing position of the connecting member 53 in the stroke direction of the valve shaft 20. Therefore, when adjusting the feedback lever 52 so that it is perpendicular to the valve stem 20 at an intermediate position in the stroke of the valve stem 20, the connecting member 53, which is passed through the elongated hole 52a of the feedback lever 52, is moved along the stroke direction along the connecting member fixing groove 72a of the lever adjustment connecting member 70, which is fixed to the valve stem 20 via a fixing member 80, thereby adjusting the feedback lever 52 to be perpendicular to the valve stem 20, and the connecting member 53 can be fixed to the lever adjustment connecting member 70 at that adjustment position.

[0041] The connecting member 53 is inserted with the side with the threaded 53b facing the insertion end, with a washered nut 54 interposed between it and the elongated hole 52a of the feedback lever 52 and the connecting member fixing groove 72a of the lever adjustment connecting member 70. A groove-fit nut 55 is then screwed onto the threaded portion of the connecting member 53 that is pulled out to the back side of the lever adjustment connecting member 70, and the connecting member 53 is fastened and fixed to the lever adjustment connecting member 70 by both the washered nut 54 and the groove-fit nut 55.

[0042] With the two nuts, the washered nut 54 and the groove-fit nut 55, loosened, the connecting member 53 can be moved along the connecting member fixing groove 72a to adjust the direction of the swing of the feedback lever 52. By fastening the two nuts 54 and 55 with the lever adjustment connecting member 70 in between, the feedback lever 52 can be fixed to the lever adjustment connecting member 70 in the direction adjusted within the connecting member fixing groove 72a. The movable state of the connecting member 53 is when the two nuts 54 and 55 are loosened and the connecting member 53 can be moved along the connecting member fixing groove 72a, while the fixed state is when the two nuts 54 and 55 are tightened with the lever adjustment connecting member 70 in between, thereby fixing the connecting member 53 to the lever adjustment connecting member 70.

[0043] It is preferable that such a lever adjustment connecting member 70 be designed to expand the adjustment range of the fixing position of the connecting member 53 to correspond to the adjustment range expected to be required by different control valves 1. For example, as shown in Figure 5, by using different sizes of control valves, it is desirable to expand the adjustment range of the fixing position of the connecting member 53 to accommodate control valves with different stroke widths W1 and W2. Specifically, the lever adjustment connecting member 70 is configured such that the length of the connecting member fixing groove 72a can accommodate the adjustment range of a control valve that is larger in size and has a larger stroke width W1, which requires a larger adjustment range than the adjustment range of a control valve that is smaller in size and has a smaller stroke width W2. By setting the adjustment range to accommodate different control valves in this way, a single lever adjustment connecting member 70 can be used for different control valves, which is very advantageous in terms of cost.

[0044] <Regarding the fixing member 80> In this embodiment, the lever adjustment connecting member 70 is fixed to a predetermined position on the valve stem 20 via the fixing member 80.

[0045] The fixing member 80 has a split structure, and the divided parts 81 and 82 are stacked on top of each other with bolts B with the valve stem 20 in between, and fixed to a predetermined position on the valve stem 20. This fixing member 80 also functions to connect the drive shaft 33 and the stem 21, with the lower end of the drive shaft 33 and the upper end of the stem 21 in between, and the divided parts 81 and 82 are superimposed on each other.

[0046] Inside the fixing member 80, there are abutment ends (not shown) that are formed to abut and position the drive shaft 33 and the stem 21 at predetermined positions in the axial direction. Furthermore, the fixing member 80 is stably held in a predetermined position on the valve stem 20 by a nut N that is screwed onto a threaded portion 21b formed on the upper end of the stem 21.

[0047] Furthermore, the fixing member 80 is provided with a pointer 83 that points to the scale on the opening degree indicator plate 42 attached to the yoke 41, in order to make the vertical movement position of the valve stem 20 visible. The opening degree indicator plate 42 is provided with an elongated fixing groove 42a that allows its mounting position to be adjusted in the direction of operation of the valve stem 20.

[0048] In this embodiment, the lever adjustment connecting member 70 is shown as being fixed to a predetermined position on the valve stem 20 via a fixing member 80. However, the lever adjustment connecting member 70 may also be given the function of a fixing member 80 and be directly fixed to a predetermined position on the valve stem 20. However, since the control valve 1 usually requires a drive shaft 33 on the drive unit 30 side and a stem 21 on the valve body 16 side, it is preferable from the viewpoint of sharing parts and space efficiency to connect the fixing member 80 that fixes the connecting part to the feedback lever 52 or to provide a pointer 83. Furthermore, from such a viewpoint, when the mounting position of the lever adjustment connecting member 70 is restricted, adjusting the direction of the feedback lever 52 by the positioner mounting structure 60 as in the embodiment of the present invention is more effective.

[0049] <Regarding the mounting structure of optional parts for the opening degree detection unit 40> An air regulator R, which adjusts the pressure of the air supplied to a positioner 50 fixed in a predetermined position on the yoke 41, is fixed to the yoke 41 via a mounting plate 90. Furthermore, when the control valve 1 automatically controls the fluid flow rate, fluid pressure, etc., to a predetermined amount, the operation of the valve body 16 is automatically and precisely controlled, and the drive system such as the valve shaft 20 operates frequently, making it prone to vibration. Such vibrations could cause the air regulator R to detach from its mounting point.

[0050] As shown in Figure 6, the mounting plate 90 has a bent portion 90a formed at its end by a bending process. Therefore, the mounting plate 90 is made more rigid by the bent portion 90a, which suppresses vibrations transmitted from the control valve 1, thus preventing the air regulator R from falling off the yoke 41 due to vibration.

[0051] Furthermore, since the positioner 50 is also fixed to the yoke 41 via the mounting plate 90, the rigidity of this mounting plate 90 can be increased by bending a portion of it, thereby suppressing vibrations transmitted from the control valve 1 and preventing it from falling off due to vibration. Furthermore, since optional parts other than the air regulator R can be attached to the control valve 1, similar effects may be achieved by bending parts of these parts as well.

[0052] In this embodiment, we have illustrated an example in which only one end face of the mounting plate 90 is bent. However, the area and number of bends should be appropriately adjusted according to conditions such as the type and magnitude of vibration and dimensional constraints at the mounting location of the mounting plate 90.

[0053] <Regarding Bonnet 17> The bonnet 17 has a valve stem guide hole 17a formed vertically through which the valve stem 20 is inserted and guided. The upper end is connected to the yoke 41 so as to receive the stem 21 in the valve stem guide hole 17a, and the lower end is connected to the body 10 so as to connect the valve stem guide hole 17a to the upper opening of the body 10.

[0054] <Regarding the assembly procedure for the positioner mounting structure 60 and the adjustment procedure for the feedback lever 52> Here, the assembly procedure for the positioner mounting structure 60 and the adjustment procedure for the feedback lever 52 will be explained using Figure 7 and other references. Figure 7 is a diagram illustrating the adjustment procedure for the feedback lever 52. First, the fixing member 80 is connected to the lower end of the drive shaft 33 and the upper end of the stem 21, so that the drive shaft 33 and the stem 21 form a single valve shaft 20 that extends from the drive unit 30 into the body 10. After fixing the fixing member 80 to the valve stem 20, the fixing member 80 is supported from below by screwing the nut N in until it contacts the lower surface of the fixing member 80.

[0055] Next, the lever adjustment connecting member 70 is fixed to the fixing member 80 using bolts B. This fixes the lever adjustment connecting member 70 to a predetermined position on the valve stem 20.

[0056] Next, the feedback lever 52, which is pivotably mounted on the device body 51 of the positioner 50 fixed to a predetermined position on the yoke 41, and the lever adjustment connecting member 70 are connected via the connecting member 53. The worker temporarily fastens the connecting member 53 to the lever adjustment connecting member 70 using a washered nut 54 and a groove-fit nut 55, passing the connecting member 53 through the elongated hole 52a of the feedback lever 52 and the connecting member fixing groove 72a of the lever adjustment connecting member 70. Furthermore, this temporary fastening is only necessary to maintain the state in which the feedback lever 52 and the lever adjustment connecting member 70 are connected via the connecting member 53, and does not adjust the connection position of the feedback lever 52 to the lever adjustment connecting member 70.

[0057] Next, the air in the air chamber 32 of the drive unit 30 is removed to fully close the control valve 1. As the air in the air chamber 32 of the drive unit 30 is released, the spring force of the spring 34 causes the valve stem 20 to descend to the lower stroke end position where the valve body 16 contacts the valve seat 13a.

[0058] Next, the opening degree indicator plate 42 is adjusted and fixed to a position corresponding to the valve stem 20 which is in the fully closed position. Here, the worker adjusts the fixing position of the opening degree indicator plate within the adjustment range of the elongated fixing groove 42a so that the pointer 83 of the fixing member 80 in the fully closed position points to the scale indicating the fully closed position of the opening degree indicator plate 42.

[0059] Next, air is gradually supplied to the air chamber 32 of the drive unit 30 to raise the valve stem 20 to the center position of the entire stroke width of the valve stem 20, that is, to the intermediate opening position. Thus, in order to confirm the position of the valve stem 20 at half its total stroke width, for example, the operator adjusts the position of the valve stem 20 while measuring the amount of movement of the valve stem 20 using a linear scale (not shown).

[0060] Next, the direction of the oscillation of the feedback lever 52 is adjusted so that the feedback lever 52 is oriented perpendicular to the valve stem 20, which is located in the center of the stroke width. Specifically, the two nuts 54 and 55 are loosened to make the connecting member 53 movable relative to the lever adjustment connecting member 70, that is, to make the connecting member 53 movable along the connecting member fixing groove 72a. When the feedback lever 52 is tilted from a direction perpendicular to the valve stem 20, which is at the center of the entire stroke width (see Figure 7(a)), the connecting member 53 is moved along the connecting member fixing groove 72a. As a result, the feedback lever, which is passed through the elongated hole 52a, rotates around the rotation axis 51a as the connecting member 53 moves, changing its orientation.

[0061] Next, with the feedback lever 52 oriented perpendicular to the valve stem 20 located in the center of the stroke width, the two nuts 54 and 55 are tightened to fix the connecting member 53 to the lever adjustment connecting member 70 (see Figure 7(b)). The worker then secures the connecting member 53, which is temporarily attached to the lever adjustment connecting member 70, to the lever adjustment connecting member 70 using a washer-equipped nut 54 and a groove-fit nut 55. Thus, the connecting member 53 is fixed to the lever adjustment connecting member 70 such that the feedback lever 52 is oriented perpendicular to the valve stem 20, which is located in the center of the stroke width. Furthermore, the feedback lever 52 is pivotably connected to the valve stem 20 via the connecting member 53 fixed to the lever adjustment connecting member 70. In other words, in conjunction with the operation of connecting the connecting member 53 so that the feedback lever 52 can slide freely in conjunction with the valve stem 20, the feedback lever 52 can be adjusted to be oriented perpendicular to the valve stem 20, which is located in the center of the stroke width.

[0062] The connecting member 53 is fixed to the lever adjustment connecting member 70 through a connecting member fixing groove 72a, which maintains a constant distance from the valve stem 20 in the direction perpendicular to the valve stem 20. Therefore, the connecting member 53 moves up and down in accordance with the up and down movement of the valve stem 20, while maintaining a constant distance from the valve stem 20 in a direction perpendicular to the valve stem 20, and moves along the elongated hole 52a of the feedback lever 52 while changing its distance from the rotation axis 51a of the feedback lever 52. The connecting member 53 is positioned such that the distance of the feedback lever 52 from the rotation axis 51a is minimized when the valve stem 20 is in the center of the stroke width and the feedback lever 52 is perpendicular to the valve stem 20. Therefore, the connecting member 53 moves along the elongated hole 52a in accordance with the amount by which the valve stem 20 moves up and down from the center position of the stroke width, so as the distance from the rotation axis 51a of the feedback lever 52 increases. Therefore, by fixing the connecting member to the lever adjustment connecting member 70 so as to be perpendicular to the valve stem 20 at the center position of the stroke width, when the valve stem 20 is located at the center position of the stroke width during the vertical movement of the valve stem 20, the feedback lever 52 is oriented perpendicular to the valve stem 20, and when the valve stem 20 moves up or down from the center position of the stroke width, it swings around the rotation axis 51a so as to be tilted relative to the direction perpendicular to the valve stem 20 in proportion to the amount of vertical movement.

[0063] <Regarding the oscillating motion of the feedback lever 52> The oscillation motion of the feedback lever 52 will be explained using Figure 8. Figure 8 shows (a) the state in which the valve stem 20 is located at the lower end of the stroke, (b) the state in which the valve stem 20 is located at the center of the stroke, and (c) the state in which the valve stem 20 is located at the upper end of the stroke. The control valve 1 is operated with the feedback lever 52 adjusted so that it is perpendicular to the valve stem 20, which is located in the center of the stroke width. As described above, the control valve 1 automatically controls the valve opening by having the positioner 50 calculate the difference between the set value of the valve opening instructed from a higher-level device (not shown) and the measured value of the valve opening of the control valve 1, and outputting a control signal generated based on that difference as an air signal to the drive unit 30. The valve opening of the control valve 1 changes as the valve stem 20 moves up and down between the upper end and lower end of its stroke. For example, when the valve stem 20 moves to the lower end of its stroke, which is the fully closed position (see Figure 8(a)), the feedback lever 52 rotates around the rotation axis 51a such that it is tilted at an angle A clockwise in the figure with respect to a direction perpendicular to the valve stem 20 (see Figure 8(b)).

[0064] On the other hand, when the valve stem 20 is moved to the upper stroke position where it is fully open (see Figure 8(c)), the feedback lever 52 rotates so as to tilt at an angle A counterclockwise in the figure with respect to the direction perpendicular to the valve stem 20. In other words, as the valve stem 20 moves up and down between the upper and lower stroke positions, the feedback lever 52 swings around the axis of rotation 51a so as to tilt symmetrically with respect to the feedback lever 52, which is perpendicular to the valve stem 20.

[0065] <Effects of the Embodiment> As described above, the mounting structure 60 for the control valve according to the embodiment has a lever adjustment connecting member 70 that is fixed to a predetermined position on the valve shaft 20 of the control valve 1 and fixes the connecting member 53 so as to be able to adjust the direction of the swing of the feedback lever 52 of the positioner 50. When connecting the feedback lever 52 of the positioner 50 to the valve shaft 20 via the connecting member 53, the connecting member 53 is fixed while being adjusted so that the direction of the swing of the feedback lever 52 is perpendicular to the valve shaft 20 at the center position of the stroke of the valve shaft 20. Therefore, the direction of the swing of the feedback lever 52 can be adjusted in conjunction with the work of fixing the connecting member 53 to the lever adjustment connecting member 70. Furthermore, the location for adjusting the direction of the swing of the feedback lever 52 and the location for fixing the connecting member 53 to the lever adjustment connecting member 70 can be consolidated and provided together. Therefore, with a simple configuration, the connection position of the feedback lever 52 to the valve stem 20 can be easily adjusted.

[0066] Furthermore, according to the mounting structure 60 for the control valve positioner of the embodiment, the lever adjustment connecting member 70 is configured such that the connecting member 53 can be in both a movable state, where it can move along the stroke direction of the valve shaft 20 relative to the lever adjustment connecting member 70, and a fixed state, where it is fixed at a position adjusted in the stroke direction. When the connecting member 53 is in the movable state, the direction of the swing of the feedback lever 52 can be adjusted, and when the connecting member 53 is in the fixed state, the feedback lever 52 can swing freely in accordance with the operation of the valve shaft 20. Therefore, the connection position of the feedback lever 52 with respect to the valve shaft 20 can be adjusted by a series of operations, which involves moving the connecting member 53 in the stroke direction relative to the lever adjustment connecting member 70 and fixing it.

[0067] Furthermore, according to the mounting structure 60 for the control valve according to the embodiment, the connecting member 53 is fixed to the lever adjustment connecting member 70 at a position closer to the positioner 50 than the valve shaft 20 in a direction perpendicular to the valve shaft 20. This allows the connecting member 53 to be fixed to the lever adjustment connecting member 70 while adjusting its position to a position that is less likely to interfere with the valve shaft 20, and as a result, the connection position of the feedback lever 52 to the valve shaft 20 can be easily adjusted. Furthermore, since the feedback lever 52 rotates around the rotation axis 51a, the range of oscillation can be kept smaller at the position of the lever adjustment connecting member 70 than at the position of the valve stem 20. Therefore, by fixing the connecting member 53 to the lever adjustment connecting member 70 at a position closer to the positioner 50, the adjustment range can be made much smaller than if the direction of oscillation of the feedback lever 52 were adjusted at the position of the valve stem 20.

[0068] Furthermore, according to the mounting structure 60 for the control valve positioner of the embodiment, the lever adjustment connecting member 70 is a plate-shaped member and has a valve shaft fixing plate portion 71 that is fixed in a position that overlaps the valve shaft 20 when viewed from the radial direction of the valve shaft 20, and a connecting member fixing plate portion 72 that is wider in the stroke direction of the valve shaft 20 than the valve shaft fixing plate portion 71 and adjusts and fixes the position of the connecting member 53 in the stroke direction. As a result, the range in which the direction of the feedback lever 52 can be adjusted in a position that is less likely to interfere with the valve shaft 20 can be expanded while keeping material costs and weight down.

[0069] Furthermore, according to the mounting structure 60 for the control valve positioner of the embodiment, there is a fixing member 80 that is fixed to a predetermined position on the valve shaft 20, and the lever adjustment connecting member 70 is fixed to the valve shaft 20 via the fixing member 80, thereby allowing the fixing member 80 to have additional functions such as an indicator pointer, and the lever adjustment connecting member 70 to have a simple configuration focused on the function of adjusting the position of the feedback lever 52.

[0070] Furthermore, according to the mounting structure 60 for the control valve of the embodiment, the lever adjustment connecting member 70 has a connecting member fixing groove 72a that extends parallel and linearly in the stroke direction, allowing for adjustment of the amount of adjustment of the fixed position of the connecting member 53 in the stroke direction of the valve shaft 20. As a result, the orientation of the feedback lever 52 can be adjusted by sliding the connecting member 53 along the connecting member fixing groove 72a, and the feedback lever 52 can be easily adjusted and fixed in a direction perpendicular to the valve shaft 20.

[0071] Furthermore, according to the mounting structure 60 of the control valve according to the embodiment, the lever adjustment connecting member 70 expands the adjustment range of the fixing position of the connecting member 53 to correspond to the adjustment range expected to be required for control valves with different stroke amounts. As a result, it can be made into a common part that can be used for different control valves, and consequently, manufacturing costs can be reduced.

[0072] Furthermore, according to the control valve 1 according to the embodiment, by providing the mounting structure 60 for the positioner of the control valve, the same effects as those provided by the mounting structure 60 for the positioner of the control valve can be achieved.

[0073] (modified version) Next, a modified example of the mounting structure 60 for the control valve positioner according to the embodiment will be described using Figure 9. Figure 9 is an exploded perspective view showing a modified example of the positioner mounting structure 60. The mounting structure 160 for the positioner of the control valve in this modified example differs from the mounting structure 60 for the positioner of the control valve in the embodiment in that a plurality of connecting member fixing grooves 172a are provided on the lever adjustment connecting member 170. In the modified example of the mounting structure 160 for the control valve, the same reference numerals are used for the same parts as in the embodiment, thereby omitting redundant explanations.

[0074] In this modified example, the mounting structure 160 of the control valve positioner has three connecting member fixing grooves 172a arranged in the stroke direction on the lever adjustment connecting member 170.

[0075] In this type of mounting structure 160 for the control valve, when adjusting the feedback lever 52 so that it is perpendicular to the valve stem 20 at an intermediate position in the stroke of the valve stem 20, the connecting member 53 passed through the elongated hole 52a of the feedback lever 52 moves along the stroke direction along one of the connecting member fixing grooves 172a provided on the lever adjustment connecting member 170 which is fixed to the valve stem 20 via a fixing member 80, thereby adjusting the feedback lever 52 to be perpendicular to the valve stem 20, and the connecting member 53 can be fixed to the lever adjustment connecting member 170 at that adjusted position. In other words, in conjunction with the operation of connecting the connecting member 53 so that the feedback lever 52 can slide freely in conjunction with the valve stem 20, the feedback lever 52 can be adjusted to be oriented perpendicular to the valve stem 20, which is located in the center of the stroke width.

[0076] Furthermore, the number of connecting member fixing grooves 172a is not limited to three; it is preferable to provide an appropriate number depending on the position where the connecting member 53 is adjusted and fixed. For example, for control valves with different stroke widths for the valve stem 20, multiple connecting member fixing grooves 172a may be provided corresponding to each control valve.

[0077] While embodiments of this disclosure have been described above, this disclosure is not limited to the embodiments described above, and various modifications are possible without departing from its spirit.

[0078] In this embodiment, a control valve 1 that operates in reverse is illustrated as an example, but the mounting structure 60 for the positioner of the control valve can also be applied to a control valve that operates in the forward direction.

[0079] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The embodiments described above may be omitted, replaced, or modified in various forms without departing from the scope and spirit of the appended claims. [Explanation of Symbols]

[0080] 1. Control valve 20 Valve stem 21. Stem (valve shaft) 33. Drive shaft (valve shaft) 50 Positioner 52 Feedback Lever 53 Connecting member Mounting structure for 60 and 160 positioners 70, 170 Lever adjustment connecting member 71 Valve shaft fixing plate 72 Connecting member fixing plate section 72a, 172a Connecting member fixing groove 80 Fixing member

Claims

1. In a mounting structure for a control valve positioner, the positioner's feedback lever is connected to the valve shaft via a connecting member so as to be able to swing around the rotation axis in accordance with the movement of the control valve's valve shaft, A mounting structure for a control valve positioner, characterized by having a lever adjustment connecting member fixed to a predetermined position on the valve shaft, which fixes the connecting member so as to be able to adjust the direction of the swing of the feedback lever.

2. The lever adjustment connecting member is configured to allow both a movable state in which the connecting member can move along the stroke direction of the valve shaft relative to the lever adjustment connecting member, and a fixed state in which it is fixed at a position adjusted in the stroke direction. The mounting structure for a control valve positioner according to claim 1, wherein, in the movable state, the direction of the swing of the feedback lever is adjustable, and in the fixed state, the feedback lever is swingable in accordance with the movement of the valve shaft.

3. The mounting structure for a control valve positioner according to claim 1, wherein the connecting member is fixed to the lever adjustment connecting member at a position closer to the positioner than the valve shaft in a direction perpendicular to the valve shaft.

4. The mounting structure for a control valve positioner according to claim 3, wherein the lever adjustment connecting member is a plate-shaped member and comprises a valve shaft fixing plate portion fixed in a position that overlaps the valve shaft when viewed from the radial direction of the valve shaft, and a connecting member fixing plate portion provided wider in the stroke direction of the valve shaft than the valve shaft fixing plate portion, for adjusting and fixing the connecting member in the stroke direction.

5. The valve stem has a fixing member that is fixed to a predetermined position, The mounting structure for a control valve positioner according to claim 1, wherein the lever adjustment connecting member is fixed to the valve shaft via the fixing member.

6. The control valve positioner mounting structure according to claim 1, wherein the lever adjustment connecting member has a connecting member fixing groove that extends parallel and linearly in the stroke direction, allowing for an adjustment amount of the fixing position of the connecting member in the stroke direction of the valve shaft.

7. The positioner mounting structure for a control valve according to claim 1, wherein the lever adjustment connecting member has an expanded adjustment range for the fixing position of the connecting member to correspond to the adjustment range expected to be required for control valves with different stroke amounts.

8. A control valve characterized by having a mounting structure for the positioner of the control valve as described in claim 1.

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