JP5443706B2 - Valve positioner for pneumatic actuator - Google Patents

Description

  The present invention is directly connected to a valve in a method of controlling a control valve composed of a pneumatic drive unit and a valve used in an automation facility of a process industry such as an oil refining apparatus, a chemical apparatus, a steelmaking machine, and a papermaking apparatus. The present invention relates to a valve positioner for a pneumatic drive unit that uses as a feedback a flexible wire used to control the drive shaft of the pneumatic drive unit to a position corresponding to an input signal.

In the conventional valve positioner, the position feedback associated with the operation of the pneumatic drive unit is transmitted to the valve positioner as a mechanical rotation angle via a transmission pin to a fixed lever with a clamp on the drive shaft. There are things like lever and transmission pin type. Also, electronic positioners equipped with a microprocessor are commercially available in which an opening degree detection unit attached to a pneumatic drive unit and the positioner main body are separated and connected by an electric wiring cable. Further, as shown in Patent Documents 1 and 2 below, some valve opening display devices are connected from a valve drive shaft to an opening meter with a wire. In addition, as disclosed in Patent Document 3 below, there is a valve opening degree detection mechanism that is connected by an operation wire from a rotary shaft of a rotary valve.
Japanese Utility Model Publication No.59-195275 Japanese Utility Model Publication No. 53-043536 JP 2001-153260 A

  In order to maintain a continuous feedback function over a long period of time, the conventional valve positioner needs to maintain its position relative to the pneumatic drive part of the control valve. Must not. Therefore, the vibration of the control valve is also transmitted to the valve positioner, which affects the internal mechanism of the valve positioner with a precise structure, which may cause damage to the valve positioner, such as loss of accuracy and induction of resonance vibration. is there.

  In addition, when the fluid flowing in the control valve is hot, the temperature rise of the connection part due to heat conduction from the valve is conducted to the valve positioner, which may exceed the use limit and may limit the place of use. .

  Since the control valve is installed in the piping of the plant, it may be installed in a high place or a place where it is difficult to work depending on the design situation of the plant. As a result, adjustment and maintenance work of the valve positioner becomes difficult and dangerous. May be accompanied.

  On the other hand, in order to avoid the above-mentioned problems, a commercially available electronic positioner has only the opening degree detection unit attached to the pneumatic drive unit and is separated from the positioner main body. Not only are the components exposed to the vibrations and high temperatures described above, but also noise may be induced in the electric wiring cable connected to the positioner body to cause malfunction.

  The flexible wire as described in Patent Documents 1, 2, and 3 is used as a valve opening degree display device or a valve opening degree detection mechanism, and only displays or detects the valve opening degree of the valve. Therefore, the air pressure of the pneumatic drive unit cannot be controlled.

  An object of the present invention is to solve the above-described problems and to realize a valve positioner for a pneumatic drive unit that can be used in a place with a lot of vibration, a high temperature place, a high place or a place where work is difficult.

  In order to solve the above-described problems, the present invention is provided such that one end of a flexible wire is rotatably attached to a drive shaft of a pneumatic drive unit directly connected to a valve, and the other end is a feedback lever or a feedback pulley of the valve positioner. The position information associated with the operation of the drive unit is linked to the feedback lever or the feedback pulley of the valve positioner.

  Since the valve positioner for the pneumatic drive unit of the present invention can be installed away from the control valve, damage to the valve positioner due to the vibration of the valve can be suppressed, and the influence on the leaf spring and the like due to high temperature and the deterioration of rubber can be prevented. As a result, the life of the valve positioner can be extended and maintenance costs can be greatly reduced.

  In addition, since a flexible wire is used, the degree of freedom in positioning the feedback lever or feedback pulley and the drive shaft of the drive unit is increased, and the valve positioner can be installed at any position. There are no restrictions on the location, making installation easy.

  Furthermore, since the valve positioner can be installed in a safe place, adjustment and maintenance work of the valve positioner can be performed safely, and there is no danger.

  Hereinafter, the best mode for carrying out the present invention will be described in detail based on examples with reference to the drawings.

  Example 1 is an example in the case of being mounted on a linear pneumatic drive unit. In FIG. 1, the wire 4 is screwed by a pivotable joint 3 to a feedback lever 12 fixed to a drive shaft 11 of a pneumatic drive unit 10. On the other hand, the other end was screwed to a feedback lever 2 of the valve positioner 1 with a joint 3 that can be rotated. The wire 4 is formed so that it can slide smoothly in the flexible sleeve 6.

  The clasp 5 of the sleeve 6 on the pneumatic drive unit 10 side is fixed to the mounting plate 8. The stopper 5 on the valve positioner 1 side is fixed to a mounting plate 7 fixed to the bracket 15 of the valve positioner 1.

  Since the cam 17 is attached to the cam shaft 16 to which the feedback lever 2 of the valve positioner 1 is attached, and the rotation angle range of the cam 17 is set to 45 degrees, the movement of the drive shaft 11 of the control valve According to the stroke range, the length from the cam shaft 16 of the feedback lever 2 to the mounting portion to which the joint 3 is attached is adjusted so that the rotation angle range of the cam 17 is 45 degrees. In the concrete attachment, the rotatable joint 3 was attached according to the stroke scale of the drive shaft 11 displayed in the long hole of the feedback lever 2.

  As a result, when the drive shaft 11 of the pneumatic drive unit 10 moves in the vertical direction, the attachment portion of the joint 3 of the feedback lever 2 at the other end moves on an arc and is connected to the feedback lever 2. The cam 17 is rotated in the range of 0 to 45 degrees. In addition, the attachment position of the wire 4 is adjusted and fixed by the long holes provided in the longitudinal direction of the attachment plates 7 and 8 of the clasp 5 of the sleeve 6 so that the wire 4 operates smoothly in the sleeve 6.

  Since the vertical movement of the drive shaft 11 is converted into the rotation of the feedback lever 2, it is necessary to correct the linearity in order to improve accuracy, but the adjustment is corrected by the shape of the cam 17. .

  The wire 4 operates smoothly with respect to the pull on the pneumatic drive unit 10 side, but the pull on the valve positioner 1 side in the reverse direction is insufficient in tension, so the attachment portion of the joint 3 of the feedback lever 2 A tension adjusting spring 9 was attached in the vicinity.

  The second embodiment is an embodiment in the case of being attached to a pneumatic actuator for a feedback lever type rotary valve. In FIG. 2, the wire 4 is screwed to the feedback lever 12 fixed to the drive shaft 11 of the pneumatic drive unit 10 with a rotatable joint 3. On the other hand, the other end was screwed to a feedback lever 2 of the valve positioner 1 with a joint 3 that can be rotated.

  The clasp 5 of the sleeve 6 on the pneumatic drive unit 10 side is fixed to the mounting plate 8. The stopper 5 on the valve positioner 1 side is fixed to the mounting plate 7.

  Since the cam 17 is attached to the cam shaft 16 to which the feedback lever 2 of the valve positioner 1 is attached, and the rotation angle range of the cam 17 is set to 90 degrees, the rotation of the drive shaft 11 of the control valve According to the angular range, the length from the cam shaft 16 of the feedback lever 2 to the mounting portion to which the joint 3 is attached is adjusted so that the rotational angle range of the cam 17 is 90 degrees. In the specific attachment, considering the rotation angle range of the drive shaft 11 and the rotation angle range of the cam 17 and the length from the center of the drive shaft 11 to the attachment portion of the joint 3 on the feedback lever 12, The fixing position of the attachment part of the feedback lever 2 and the joint 3 was determined.

  Thus, when the drive shaft 11 of the pneumatic drive unit 10 rotates, the attachment portion of the joint 3 of the feedback lever 2 at the other end operates on an arc, and the cam 17 connected to the feedback lever 2 is moved. Rotate in the range of 0-90 degrees. In addition, the attachment position of the wire 4 is adjusted and fixed by the long holes provided in the longitudinal direction of the attachment plates 7 and 8 of the clasp 5 of the sleeve 6 so that the wire 4 operates smoothly in the sleeve 6.

  In the case of the second embodiment, since the movement of the drive shaft 11 in the left and right rotational directions operates in conjunction with the rotation of the feedback lever 2, no correction of linearity is necessary.

  The wire 4 operates smoothly with respect to the pull on the pneumatic drive unit 10 side, but the pull on the valve positioner 1 side in the reverse direction is insufficient in tension, so the attachment portion of the joint 3 of the feedback lever 2 A tension adjusting spring 9 was attached in the vicinity.

  In the case of the second embodiment, the case where the rotation angle range of the cam 17 is 90 degrees has been described.

  The third embodiment is an embodiment in the case of being attached to a pneumatic driving unit for a feedback pulley type rotary valve. In FIG. 3, the wire 4 is screwed with a joint 3 that can rotate on a feedback pulley 19 fixed to the drive shaft 11 of the pneumatic drive unit 10. On the other hand, the other end was screwed to the feedback pulley 18 of the valve positioner 1 with a rotatable joint 3.

  As in the other examples, the stopper 5 of the sleeve 6 on the pneumatic drive unit 10 side was fixed to the mounting plate 8. The stopper 5 on the valve positioner 1 side is fixed to the mounting plate 7.

Since the cam 17 is attached to the cam shaft 16 to which the feedback pulley 18 of the valve positioner 1 is attached, and the rotation angle range of the cam 17 is set to 90 degrees, the rotation of the drive shaft 11 of the control valve According to the angular range, the diameter of the feedback pulley 18 was adjusted with respect to the diameter of the feedback pulley 19 so that the rotational angle range of the cam 17 was 90 degrees. In the specific attachment, the diameter of the feedback pulley 18 is determined in consideration of the rotation angle range of the drive shaft 11, the rotation angle range of the cam 17, and the diameter of the feedback pulley 19, and the joint 3 is attached. .

  As a result, when the drive shaft 11 of the pneumatic drive unit 10 rotates, the attachment portion of the joint 3 of the feedback pulley 18 at the other end operates on an arc, and the cam 17 connected to the feedback pulley 18 is moved. Rotate in the range of 0-90 degrees. In addition, the attachment position of the wire 4 is adjusted and fixed by the long holes provided in the longitudinal direction of the attachment plates 7 and 8 of the clasp 5 of the sleeve 6 so that the wire 4 operates smoothly in the sleeve 6.

  Similar to the second embodiment, also in the third embodiment, the movement of the drive shaft 11 in the left and right rotational directions operates in conjunction with the rotation of the feedback pulley 18 on the valve positioner 1 side. No correction is necessary.

  As in the other embodiments, the wire 4 operates smoothly with respect to the pull on the pneumatic drive unit 10 side, but the pull on the valve positioner 1 side in the reverse direction has insufficient tension. A spring 9 for tension adjustment was attached to the attachment portion of the joint 3 of the pulley 18.

  In the case of the third embodiment, the case where the rotation angle range of the cam 17 is 90 degrees has been described, but the same can be applied to the case where the rotation angle range is 90 degrees or more.

Explanatory drawing of Example 1 of this invention Explanatory drawing of Example 2 of this invention Explanatory drawing of Example 3 of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Valve positioner 2 Feedback lever 3 Joint 4 Wire 5 Clasp 6 Sleeve 7 Mounting plate 8 Mounting plate 9 Spring 10 Pneumatic drive part 11 Drive shaft 12 Feedback lever 13 Tube 14 Support tool 15 Bracket 16 Cam shaft 17 Cam 18 Feedback Pulley 19 Feedback pulley

Claims (2)

In a method of controlling a control valve composed of a pneumatic drive unit and a valve,
Attach one end of the wire that can smoothly slide in the flexible sleeve to the drive shaft of the pneumatic drive unit directly connected to the valve via a rotatable joint ,
The other end is attached via a pivotable joint to the feedback lever or feedback pulley of the valve positioner,
In order to suppress damage to the valve positioner due to vibration of the control valve, the valve positioner is installed at an arbitrary position away from the control valve having vibration through the wire,
A valve positioner for a pneumatic drive unit, characterized in that the position information associated with the operation of the drive unit is linked to the feedback lever or feedback pulley of the valve positioner. 2. A valve positioner for a pneumatic drive unit according to claim 1, further comprising a tension adjusting spring in the vicinity of the attachment portion of the feedback lever or feedback pulley joint on the valve positioner side of the wire of claim 1.

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