JP2018179231A - Valve positioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve positioner capable of accurately transmitting opening change of a valve to an opening sensor without influence of vibration, and also accurately detecting opening of a valve even in a case of being used outdoor.SOLUTION: A valve positioner includes a first connection member 16 rotating integrally with a valve drive shaft 7, and an opening sensor unit 3 configured to detect a rotation angle of a detection shaft 6. The valve positioner includes: a second connection member 18 rotating integrally with the detection shaft 6; and a third connection member 19 connected to the first connection member 16 and the second connection member 18 in a movable manner through first and second slide bearings 45, 47, and configured to transmit rotation of the first connection member 16 to the second connection member 18. The valve positioner includes a dust removal device 24 configured to discharge compressed air to the atmosphere via a slide contact part of the first and second slide bearings 45, 47.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a valve positioner provided with an opening degree sensor that detects a rotation angle of a rotation shaft of a valve.

  A conventional general pneumatically driven valve is equipped with a valve positioner that detects the opening degree and controls the air pressure to the target opening degree. This kind of valve positioner is configured by housing components such as a pneumatic mechanism, an opening degree sensor, an electronic circuit and the like in one case. Thus, when the entire valve positioner is attached to the valve, the entire positioner is also vibrated in an operating environment where the valve vibrates. When the valve positioner vibrates, the detection accuracy may be reduced due to the vibration of the component that transmits the change in the opening of the valve to the opening sensor, and the controllability of the valve may be impaired. In addition, there is a possibility that the contact between parts will wear and the life of the valve positioner will be shortened.

  As a valve positioner which does not receive the influence of valve vibration, there are some which are indicated, for example in patent documents 1. The valve positioner disclosed in Patent Document 1 is installed at a position different from the valve, and includes a wire for transmitting a change in the opening of the valve to the opening sensor.

JP, 2009-264573, A

  However, in the valve positioner shown in Patent Document 1, there is a problem that it is difficult to use it outdoors. Outside, the valve positioner is exposed to dust, particularly sand when used in desert areas. In addition, if this valve positioner is used in a plant where dust flies in the production process, it will be exposed to dust that is staying in the atmosphere. In such a situation, foreign matter such as dust gets into the outer for holding the wire, and the sliding of the wire is impaired, and the change in the opening degree of the valve can not be transmitted properly. As a result, the opening degree of the valve is not detected correctly, and the control of the opening degree to feed back it becomes inaccurate.

  In order to solve such a problem, it is conceivable to apply grease to the opening of the outer which is an inlet of dust or the like. However, in outdoor environments, it may be exposed to strong rain, and in tropical regions it may be exposed to strong sunlight at high temperatures, so the grease may be washed away or dry and solidify. It is not always perfect.

  The present invention has been made to solve such a problem, and the valve opening change can be accurately transmitted to the opening sensor without being affected by vibration, and the valve can be opened even when used outdoors. It is an object of the present invention to provide a valve positioner capable of accurately detecting the degree.

  In order to achieve this object, a valve positioner according to the present invention has a first connecting member that rotates integrally with a rotary valve drive shaft, and a detection shaft, and detects the rotation angle of this detection shaft A second connection member that rotates integrally with the detection shaft, and the first connection member and the second connection member are each movably connected via a slide bearing, A third connecting member for transmitting the rotation of the connecting member to the second connecting portion; and a dustproof device for discharging pressure air to the atmosphere via the sliding contact portion of the slide bearing.

  In the valve positioner according to the present invention, the detection shaft is parallel to the valve drive shaft, and the first connecting member extends in the axial direction of the valve drive shaft at a position eccentric to the valve drive shaft. It has a cylindrical first shaft portion, and the second connection member has a cylindrical second shaft portion extending in a direction orthogonal to the detection axis, and the third connection member is A first bearing portion rotatably supported by the slide bearing on the first shaft portion, and an axially movable second shaft portion supported on the second shaft portion by the slide bearing And the dustproof device includes a first air passage formed in the inside of the first connecting member and a second air bearing formed in the inside of the second connecting member. It may have an air passage.

  In the valve positioner according to the present invention, the valve drive shaft is connected to a valve drive actuator operated by pneumatic pressure, and a dustproof device is supplied with pressure air from a pressure air supply common to the valve drive actuator. It is also good.

  In the valve positioner according to the present invention, the slide bearing may be formed of metal.

  In the present invention, the rotation of the valve drive shaft is transmitted from the first connection member to the second connection member via the third connection member, and the rotation angle of the second connection member and the detection shaft is the opening sensor unit Detects. A slide bearing interposed between the first and second connecting members and the third connecting member absorbs relative displacement due to minute vibration of these members. For this reason, since the connecting part portions of the first to third connecting members are not worn by vibration, it is possible to reliably transmit the change in the opening degree of the valve to the opening degree sensor.

Further, since the pressurized air is discharged from the sliding contact portion by the operation of the dustproof device, the dust floating around the slide bearing is blown away by the pressurized air. For this reason, dust can be prevented from entering the slide bearing portion from the outside.
Therefore, according to the present invention, a valve positioner capable of transmitting the change in the opening of the valve to the opening sensor without being affected by vibration and accurately detecting the opening of the valve even when used outdoors can do.

It is a side view of a connection part and a sensor part of a valve positioner concerning the present invention. It is a top view of the connection part and opening degree sensor part of a valve positioner. It is sectional drawing which expands and shows the principal part. It is a perspective view which shows the general | schematic structure of the valve positioner which concerns on this invention, and a valve | bulb. It is sectional drawing which shows other embodiment of a slide bearing.

First Embodiment
Hereinafter, one embodiment of a valve positioner according to the present invention will be described in detail with reference to FIGS.
The valve positioner 1 shown in FIG. 1 is composed of three functional parts. The first functional portion is an opening degree sensor portion 3 fixed on the lowermost bracket 2 in FIG. The second functional unit is, as shown in FIG. 4, the positioner main unit 5 connected to the opening degree sensor unit 3 via the cable 4. The third functional unit is the rotation transmission unit 8 that transmits the rotation of the valve drive shaft 7 to the detection shaft 6 of the opening degree sensor unit 3.

  The bracket 2 is provided on the valve 11 as shown in FIG. The valve 11 is opened and closed by rotation of the valve drive shaft 7. An actuator 12 for driving the valve 11 is attached to one side of the bracket 2. The actuator 12 operates with the pressure of the pressure air sent from the pressure air source 13, and is connected to the valve drive shaft 7 inside the bracket 2, and this valve drive shaft 7 has its axis C1 (see FIG. 1) Turn to one side or the other around the center. The rotation of the valve drive shaft 7 is transmitted to the opening degree sensor unit 3 via a rotation transmission unit 8 described later.

The opening degree sensor unit 3 includes a detection shaft 6 configured in parallel to the valve drive shaft 7 and an angle sensor (not shown) for detecting the rotation angle of the detection shaft 6. It is attached.
The detection shaft 6 is rotatably supported by the angle sensor in a state in which the axis C2 is parallel to the axis C2 of the valve drive shaft 7.
The angle sensor sends the rotation angle of the detection shaft 6 to the positioner body 5 as angle data.

  The positioner main unit 5 controls the operation of the actuator 12 so that the current opening degree matches the target opening degree, with the function of obtaining the current opening degree of the valve 11 using the angle data sent from the angle sensor Have a function to The positioner main body 5 according to this embodiment is supported by a base (not shown) to which the vibration of the valve 11 is not transmitted.

  As shown in FIGS. 1 and 2, the rotation transmitting unit 7 includes a first connecting member 16 fixed to the valve drive shaft 7 by the fixing bolt 15 and a second connecting member fixed to the detection shaft 6 by the fixing bolt 17. And a third connecting member 19 connecting the first connecting member 16 and the second connecting member 18 together. The first connection member 16 rotates integrally with the valve drive shaft 7, and the second connection member 18 rotates integrally with the detection shaft 6.

As shown in FIG. 2, the first connecting member 16 has an arm 21 formed in an L shape in plan view. The arm 21 is composed of a first arm piece 21a which is a short side of the L-shape and a second arm piece 21b which is a long side of the L-shape. The first arm piece 21a and the second arm It is fixed to the valve drive shaft 7 at the connecting portion with the arm piece 21b.
The first arm piece 21 a shown in FIG. 2 extends from the valve drive shaft 7 in the direction opposite to the opening degree sensor unit 3.

A valve-side connector pin 22 described later is provided at the tip of the first arm piece 21a. The first arm piece 21a and the valve-side connector pin 22 are drawn as being integrally formed in FIG. 1, but in reality they are separately formed and coupled by a coupling means such as welding or screws. ing.
The second arm piece 21 b is for visually confirming the valve opening degree, and is formed in a shape in which the tip end portion is sharpened. A scale 23 indicating the valve opening is provided on the top surface of the bracket 2 at a position corresponding to the tip of the second arm piece 21b.

  The valve side connector pin 22 cooperates with the arm 21 to constitute the first connecting member 16. The valve-side connector pin 22 according to this embodiment is formed in a cylindrical shape and is disposed at a position eccentric to the valve drive shaft 7 and is a direction parallel to the axis C1 of the valve drive shaft 7 from the arm 21 It extends upward (in the direction away from the valve 11). In this embodiment, the valve side connector pin 22 corresponds to the "first shaft portion" in the present invention. Inside the valve-side connector pin 22 and the arm 21, a first air passage 25 which constitutes a part of a dustproof device 24 described later is formed.

  The second connecting member 18 includes a cylindrical body 31 having one end attached to the detection shaft 6, a sensor connector pin 32 screwed to the other end of the cylindrical body 31, and the sensor connector pin 32. It is comprised by the lock nut 33 screwed together by the thread part 32a. The cylindrical body 31 extends in a direction perpendicular to the axis C2 of the detection axis 6 and, as shown in FIG.

  The sensor-side connector pin 32 has a cylindrical base 34 having a screw 32a protruding from it, and a shaft 35 which is thinner than the base 34 and protrudes from the base 34 on the opposite side of the screw 32a. , And the cylindrical body 31 are arranged on the same axis. The total length of the second connection member 18 according to this embodiment can be adjusted by changing the amount of screwing when attaching the sensor-side connector pin 32 to the cylindrical body 31. Inside the sensor-side connector pin 32, a second air passage 36 of a dustproof device 24 described later is formed. In this embodiment, the sensor-side connector pin 32 corresponds to the "second shaft portion" in the present invention.

The third connecting member 19 includes a first bearing 41 connected to the valve connector pin 22, a second bearing 42 connected to the sensor connector pin 32, a first bearing 41 and a first bearing 41. And a connecting portion 43 for connecting the two bearing portions 42.
The first bearing portion 41 has a metal first cylinder 44 through which the valve side connector pin 22 passes. A first slide bearing 45 is fixed to the inner peripheral surface of the first cylinder 44. In the first slide bearing 45, a valve side connector pin 22 is slidably fitted. The first bearing 41 is rotatably supported by the valve-side connector pin 22 by the first slide bearing 45.

  The second bearing portion 42 has a metal second cylinder 46 through which the sensor connector pin 32 is passed. A second slide bearing 47 is fixed to the inner peripheral surface of the second cylinder 46. The sensor-side connector pin 32 is slidably fitted in the second slide bearing 47. The second bearing portion 42 is supported movably in the axial direction of the sensor side connector pin 32 by the second slide bearing 47 on the sensor side connector pin 32. The first slide bearing 45 and the second slide bearing 47 according to this embodiment are formed of a plastic material having a small coefficient of friction. In this embodiment, the first slide bearing 45 and the second slide bearing 47 correspond to the "slide bearing" in the present invention.

The connection portion 43 is constituted by a pair of metal plates 48, 48 sandwiching the axial end portion of the second cylinder 46 from both sides in the radial direction. The metal plates 48 are respectively welded to the outer peripheral surface of the first cylinder 44 and the outer peripheral surface of the second cylinder 46. Between the pair of metal plates 48, a space S opened in the vertical direction is formed.
The third connecting member 19 including the connecting portion 43 and the first and second bearings 41 and 42 described above is movably connected to the first connecting member 16 via the first slide bearing 45. And is movably connected to the second connection member 18 via the second slide bearing 47.

The dustproof device 24 is for preventing foreign matter such as dust from entering the first and second slide bearings 45 and 47. The dustproof device 24 according to this embodiment guides a part of the pressure air supplied to the actuator 12 to the sliding contact portions 45a and 47a (see FIG. 3) of the first and second sliding bearings 45 and 47, and this slippage The pressure in the contact portions 45a and 47a is made higher than the atmospheric pressure. The sliding contact portion 45 a of the first sliding bearing 45 referred to here is a fitting portion between the valve connector pin 22 and the first sliding bearing 45. The sliding contact portion 47 a of the second sliding bearing 47 is a fitting portion between the sensor connector pin 32 and the second sliding bearing 47.
The dustproof device 24 is upstream of the air supply pipe 51 (see FIG. 4) to which the pressure air is supplied from the pressure air supply source 13 to guide the compressed air to the first and second slide bearings 45 and 47. It has first and second hoses 52 and 53 connected at the side end, a first air passage 25 in the valve side connector pin 22, and a second air passage 36 in the sensor side connector pin 32. ing.

The first and second hoses 52, 53 are formed of a flexible material. The downstream end of the first hose 52 is attached to the arm 21 of the first connecting member 16 and connected to the upstream end of the first air passage 25.
The downstream end of the second hose 53 is attached to the sensor connector pin 32 of the second connection member 18 and connected to the upstream end of the second air passage 36.

  As shown in FIGS. 1 and 2, the first air passage 25 extends from the upstream end opening in the upper surface of the arm 21 into the arm 21 and into the valve connector pin 22 as shown in FIG. The tip of the valve-side connector pin 22 connected to the third connecting member 19 is open to the sliding contact portion 45 a of the first sliding bearing 45. A downstream end of the first air passage 25 is formed at the axial center of the valve connector pin 22 and extends in the longitudinal direction of the valve connector pin 22 and radially around the passage hole 25a. And a plurality of communication holes 25b extending in

  The communication holes 25 b are respectively provided at a plurality of positions in a range overlapping with the first slide bearing 45 in the longitudinal direction of the valve side connector pin 22. For this reason, the pressurized air supplied to the first air passage 25 flows out from the plurality of communication holes 25b into the sliding contact portion 45a, and directs the inside of the sliding contact portion 45a to both ends of the first sliding bearing 45. Flow. Then, this pressurized air is discharged to the atmosphere from both ends of the first slide bearing 45.

  The second air passage 36 extends in the sensor connector pin 32 from the upstream end opening to the base 34 of the sensor connector pin 32, as shown in FIGS. 1 and 2, as shown in FIG. The distal end portion of the sensor connector pin 32 connected to the third connection member 19 is opened to the sliding contact portion 47 a of the second sliding bearing 47. The downstream end of the second air passage 36 is formed at the axial center of the sensor connector pin 32 and extends in the longitudinal direction of the sensor connector pin 32 and radially about the passage hole 36a. And a plurality of communication holes 36b extending in

The communication holes 36 b are respectively provided at a plurality of positions in a range overlapping with the second slide bearing 47 in the longitudinal direction of the sensor side connector pin 32. For this reason, the pressurized air supplied to the second air passage 36 flows out from the plurality of communication holes 36b into the sliding contact portion 47a, and directs the inside of the sliding contact portion 47a to both ends of the second sliding bearing 47. Flow. Then, this pressurized air is discharged from the both ends of the second slide bearing 47 to the atmosphere.
For this reason, the dustproof device 24 discharges pressurized air to the atmosphere via the sliding contact portions 45a and 47a of the first and second sliding bearings 45 and 47.

Next, the operation of the valve positioner 1 according to this embodiment will be described.
When the valve drive shaft 7 rotates, the first connecting member 16 rotates around the valve drive shaft 7. Then, the first bearing portion 41 of the third connection member 19 is moved along with the rotation operation of the first connection member 16. At this time, the movement of the third connecting member 19 is restricted by the second connecting member 18 and is only rotational movement about the detection axis 6. Therefore, the first bearing portion 41 rotates with respect to the first connection member 16, and the second bearing portion 42 moves in the axial direction with respect to the second connection member 18. Rotation is transmitted to the second connecting member 18 via the third connecting member 19 and the detection shaft 6 rotates. As a result, the rotation of the valve drive shaft 7 is transmitted from the first connection member 16 to the second connection member 18 via the third connection member 19, and the rotation angles of the second connection member 18 and the detection shaft 6 are determined. The opening sensor unit 3 detects.

  The first and second slide bearings 45, 47 interposed between the first and second connecting members 16, 18 and the third connecting member 19 allow relative displacement of these members due to minute vibration. Absorb. For this reason, since the connecting portion portions of the first to third connecting members 16, 18, 19 are not worn by vibration, the change in the opening degree of the valve 11 can be reliably transmitted to the opening degree sensor.

Further, since the valve positioner 1 is provided with the dustproof device 24 for discharging the pressurized air from the sliding contact portions 45a, 47a of the first and second sliding bearings 45, 47, the first and second sliding bearings Dust floating around 45, 47 is blown away by this pressurized air. For this reason, even if the valve positioner 1 is used in an atmosphere where dust, dust, or the like flies, dust can be prevented from entering the first and second sliding contact portions 45a and 47a from the outside.
Therefore, according to this embodiment, the change in the opening degree of the valve 11 is reliably transmitted to the opening degree sensor without being affected by the vibration, and the opening degree of the valve 11 is accurately detected even when used outdoors. Possible valve positioners can be provided.

The dustproof device 24 according to this embodiment includes a first air passage 25 formed inside the first connection member 16 and a second air passage 36 formed inside the second connection member 18. Have.
Therefore, pressurized air can be supplied to the first bearing 41 from the first air passage 25, and pressurized air can be supplied to the second bearing 42 from the second air passage 36. .
Therefore, since pressurized air can be sufficiently supplied to the first and second slide bearings 45 and 47, a valve positioner having high reliability in transmitting change in the opening degree of the valve 11 to the opening degree sensor can be provided. Can be provided.

The valve drive shaft 7 according to this embodiment is connected to a pneumatically operated valve drive actuator 12.
The dustproof device 24 is supplied with pressure air from a pressure air supply source 13 common to the valve driving actuator 12.
Therefore, part of the pressure air supplied to the valve driving actuator 12 can be supplied to the sliding contact portions 45a and 47a of the first and second sliding bearings 45 and 47, so that only the sliding contact portion 45a, There is no need for a pressurized air supply to supply pressurized air to 47a. Therefore, according to this embodiment, the present invention can be realized while suppressing the cost increase as much as possible.

Second Embodiment
The first and second slide bearings can be configured as shown in FIG. In FIG. 5, the same or equivalent members as or to those described with reference to FIGS. 1 to 4 are denoted by the same reference numerals, and the detailed description will be omitted.
The first and second slide bearings 61 and 62 shown in FIG. 5 are formed of metal. In such metal slide bearings 61 and 62, wear powder (not shown) is generated from the slide contact portions 61a and 62a. However, this wear debris is pushed out of the slide bearings 61, 62 by the pressurized air sent by the dustproof device 24. For this reason, wear powder does not stay in the slide bearings 61 and 62 and biting does not occur. In addition, the slide bearings 61 and 62 made of metal have a wider range of application temperature than plastic slide bearings.
Therefore, according to this embodiment, since sufficient performance can be obtained even in a high temperature environment or a cryogenic temperature environment, a valve positioner with higher performance can be provided.

  The dustproof device 24 shown in the above-described embodiment has a configuration in which pressure air is supplied from a pressure air supply source common to the valve driving actuator 12. However, the present invention is not limited to such a limitation, and can adopt a configuration provided with a pressure air supply source dedicated to the dustproof device.

  DESCRIPTION OF SYMBOLS 1 ... valve positioner, 3 ... opening degree sensor part, 6 ... detection axis, 7 ... valve drive axis, 12 ... valve drive actuator, 13 ... pressure air supply source, 16 ... 1st connection member, 18 ... 2nd Connecting member 19 19 third connecting member 22 valve side connector pin 24 dustproof device 25 first air passage 32 sensor side connector pin 36 second air passage 41 first Second bearing portion, 45: first slide bearing (slide bearing), 47: second slide bearing (slide bearing).

Claims (4)

A first connecting member that rotates integrally with the rotating valve drive shaft;
An opening degree sensor unit having a detection axis and detecting a rotation angle of the detection axis;
A second connecting member that rotates integrally with the detection shaft;
A third connection member that is movably connected to the first connection member and the second connection member via slide bearings, and transmits the rotation of the first connection member to the second connection portion;
A valve positioner having a dustproof device for discharging pressurized air to the atmosphere via a sliding contact portion of the sliding bearing. In the valve positioner according to claim 1,
The detection axis is configured parallel to the valve drive axis,
The first connection member has a cylindrical first shaft portion extending in the axial direction of the valve drive shaft at a position eccentric to the valve drive shaft,
The second connection member has a cylindrical second shaft extending in a direction perpendicular to the detection axis,
The third connection member is
A first bearing portion rotatably supported by the slide bearing on the first shaft portion, and an axially movable second shaft portion supported on the second shaft portion by the slide bearing And a second bearing portion,
The dustproof device is
A valve positioner comprising: a first air passage formed inside the first connecting member; and a second air passage formed inside the second connecting member. In the valve positioner according to claim 1 or 2,
The valve drive shaft is coupled to a pneumatically operated valve drive actuator.
The valve positioner is characterized in that the dustproof device is supplied with pressure air from a pressure air supply source common to the valve driving actuator. The valve positioner according to any one of claims 1 to 3.
The said slide bearing is formed of metal, The valve positioner characterized by the above-mentioned.

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