JPH078604U - Positioner - Google Patents

Abstract

(57) [Summary] [Purpose] To make it possible to easily adjust the zero point of the output pressure in an electropneumatic positioner, etc., from the outside without opening the casing of the electropneumatic converter. [Structure] Bias chamber 26 facing nozzle back pressure chamber 27
And a pilot relay 3 for introducing the supply air pressure Psup into the bias chamber. A pressure reducing valve 43 is arranged in the supply air pressure introduction flow path 42 to the bias chamber. The pressure reducing valve increases / decreases the pressure in the bias chamber opposite to the nozzle back pressure to adjust the output pressure Pout of the positioner 1 to the zero point.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a positioner suitable for application to, for example, an electropneumatic converter, an electropneumatic positioner used for a drive control unit of a pneumatic control valve, a pneumatic positioner, and the like, and particularly, a zero point adjusting means of the output pressure of the positioner. Regarding

[0002]

[Prior art]

 For example, a valve positioner 1 such as an electropneumatic positioner used for drive control of a control valve uses an electric input signal Iin in the electropneumatic conversion section 2 as a mechanical displacement amount in a nozzle flapper (see FIG. 5). Nozzle back pressure is converted into an air pressure signal by the supply air pressure Psup supplied to the nozzle flapper and the nozzle flapper gap, and then the pressure is increased by the pilot relay 3. The positioner output pressure Pout is obtained. Further, the valve displacement on the side of the control valve 5 that is moved by the output pressure Pout thus obtained is fed back to the electropneumatic conversion section 2 side via a lever connected to the valve shaft or the like. It is becoming like this.

Here, in the valve positioner 1 such as the electro-pneumatic positioner described above, in the case of being attached to the control valve 5 installed in the field such as an oil refinery, the electrical input signal is The electro-pneumatic conversion unit 2 including a control calculation unit for mechanically displacing the flapper based on the above and an electro-pneumatic converter including a nozzle flapper is housed in a case having a flameproof structure.

In the conventional valve positioner 1 and the like having the electro-pneumatic conversion portion 2 housed in the case having such a pressure-proof explosion-proof structure, the zero point adjustment of the positioner output pressure is performed by the pressure-proof explosion-proof structure as described above. This is done by adjusting the urging force of a spring attached to the flapper in the electro-pneumatic conversion unit 2 constituted by the case described above. Further, the span adjustment in the positioner 1 is performed by adjusting the connecting position of the lever for detecting the movement of the valve shaft of the control valve 5 to the valve shaft.

[0005]

[Problems to be solved by the device]

 By the way, in the conventional valve positioner 1 as described above, the means for adjusting the zero point of the output pressure of the positioner in the electro-pneumatic conversion system is provided in the pressure-proof explosion-proof case forming the electropneumatic conversion section 2. It was only attached to the nozzle flapper.

Therefore, according to such a conventional structure, in order to perform the zero point adjustment, it is necessary to open the electro-pneumatic conversion unit case, and there is a problem that a troublesome adjustment work must be performed. It was

Of course, this kind of zero point adjustment is performed as an initial setting such as zero point adjustment at the time of installation at the site, but its use may cause a zero point shift. Have to perform zero adjustment on a regular basis, and it is desirable to take some kind of measure to facilitate such zero adjustment.

Particularly, in the conventional electro-pneumatic positioner and the like, the electro-pneumatic conversion section 2 described above is often provided in a case having a pressure-proof explosion-proof structure. The zero point cannot be adjusted because the explosion-proof case cannot be opened.

Further, even outside the explosion-proof area, the zero-point adjustment cannot be performed unless the pressure-proof explosion-proof case is opened, which is not preferable in terms of workability, and some measure that can eliminate these problems. It is hoped that

The present invention has been made in view of such circumstances, and the zero point adjustment of the output pressure of the positioner can be easily performed without opening the case of the electropneumatic conversion section and by an extremely simple structure. The purpose is to get a positioner who can do it.

[0011]

[Means for Solving the Problems]

 In order to meet such a demand, the positioner according to the present invention has a bias chamber facing the nozzle back pressure chamber and a pilot relay for introducing the supply air pressure into the bias chamber, and the bias chamber is supplied to the bias chamber. A pressure reducing valve is provided in the air pressure introduction flow path, and the zero point of the output pressure can be adjusted by adjusting the pressure reducing valve.

Further, the positioner according to the present invention has a nozzle back pressure chamber, a diaphragm that defines the nozzle back pressure chamber, and a poppet valve that operates by being connected to the diaphragm. It is equipped with a pilot relay that outputs air pressure by means of an elastic member that comes into contact with the diaphragm from the nozzle back pressure chamber side in the nozzle back pressure chamber, and an adjustment screw that increases or decreases the elastic force of this elastic member. It is designed to be installed on the body of.

[0013]

[Action]

 According to the present invention, by adjusting and adjusting the supply air pressure introduced into the bias chamber facing the nozzle back pressure chamber of the pilot relay to an arbitrary pressure by the pressure reducing valve, the zero point of the electrical input signal and the output pressure is adjusted. The adjustment can be performed from the outside of the electro-pneumatic conversion unit case by a very simple adjustment operation, and the zero point adjustment can be easily and reliably performed even in the explosion-proof area.

Further, according to the present invention, the elastic force applied to the diaphragm by the elastic member provided in the nozzle back pressure chamber of the pilot relay is adjusted by adjusting the adjusting screw provided in the body of the pilot relay. By adjusting and adjusting the elastic force to the zero point, the zero point adjustment of the electrical input signal and the output pressure can be performed from the outside of the electro-pneumatic converter case by a very simple adjustment operation. However, the zero point adjustment can be performed easily and surely.

[0015]

【Example】

 1 and 2 show an embodiment of a positioner according to the present invention. In this embodiment, only the main structure of a pressure-resistant explosion-proof electropneumatic positioner is shown. In these figures, parts corresponding to those in FIG. 5 described above are given the same numbers.

First, a schematic structure of the valve positioner 1 will be briefly described with reference to FIG. 1. Reference numeral 10 is a pressure-proof explosion-proof case of the electropneumatic converter 2, and a coil forming an electropneumatic converter 11 therein. 12, a magnet 13, a fulcrum 14, and a flapper 16 and a nozzle 17 which constitute a nozzle flapper 15. Further, the pipe 20 serving as a supply air pressure introducing passage for supplying the supply air pressure Psup to the nozzle 17 and obtaining the nozzle back pressure at a portion closer to the nozzle 17 than the throttle 21 provided in the middle thereof is a wall portion of the case 10. Through the flame arrestor 10a.

Reference numeral 18 is a zero-point adjusting spring provided in a part of the flapper 16, and reference numeral 19 is a zero-point adjusting knob, which is used for initial setting when the valve positioner 1 is installed in the field. It is a thing. However, according to the present invention, as will be apparent from the following description, it is needless to say that the means (18, 19) for adjusting the zero point is not always necessary and can be appropriately omitted.

On the other hand, the pilot relay 3 for amplifying and outputting the nozzle back pressure described above has the following configuration. Here, in FIG. 1, the pilot relay 3 is shown as one belonging to the bleed type, which is a model in which a part of the supply air pressure Psup is constantly discharged to the atmosphere during normal operation.

To briefly explain the schematic configuration of the pilot relay 3, the body 22 has a supply air pressure chamber 23, an output chamber 24, an atmosphere communication chamber 25, a bias chamber 26, and an input chamber 27, and each of these chambers is provided. The supply air pressure chamber 23 and the output chamber 24 are communicated with each other by a through hole 28 formed in an inner partition wall, and a diaphragm 30 is provided between the atmosphere communication chamber 25 and the bias chamber 26 and between the bias chamber 26 and the input chamber 27. , 31 partition.

Reference numeral 32 is a piston which is supported by the central portions of the upper and lower diaphragms 30 and 31 and has a lower end portion serving as an area plate member facing the atmosphere communication chamber 25 and the output chamber 24. An O-ring 33 is fitted on the lower end side of 32, whereby the atmosphere communication chamber 25 and the output chamber 24 are defined.

Further, at the lower end of the piston 32, the other end of the communication passage 34 opening to the atmosphere communication chamber 25 is opened, and the valve shaft arranged so as to penetrate the output chamber 24 and the through hole 29. A poppet valve body 36 at the upper end of 35 is arranged facing the opening and closing of the opening. On the other hand, the through hole 29 is configured to be opened / closed by a poppet valve body 37 provided at the lower end of the valve shaft 35 on the supply air pressure chamber 23 side.

The valve shaft 35 having the poppet valve bodies 36 and 37 and forming the poppet valve is normally biased by the bias spring 38 in a direction to close both holes, and the valve shaft 35 is moved to the input chamber 27. The piston 32, which is moved by the pressure difference between each chamber depending on the magnitude of the input air pressure (nozzle back pressure Pn), and the movement of the poppet valve bodies 36 and 37, causes the pipe 39 from the output chamber 24 to operate as a valve of a control valve (not shown). The output pressure Pout supplied to the drive unit is controlled.

In the figure, 40 is a pipe for supplying Psup to the supply air pressure chamber 23, and 41 is a pipe for inputting the nozzle back pressure Pn from the supply air pressure introducing pipe 20 to the input chamber 27. Further, 42 is a pipe serving as a supply air pressure introduction flow path for introducing the supply air pressure to the bias chamber 26 facing the input chamber 27 through the upper diaphragm 31, and thereby the pressure introduced into the bias chamber 26. Then, the movement of the upper diaphragm 31 which is moved by the nozzle back pressure Pn is controlled so that the required output pressure Pout can be obtained by the piston 32 and the poppet valve bodies 36 and 37.

According to the present invention, in the pilot relay 3 of the positioner 1 having the above-described structure, the supply air pressure Psup is introduced into the bias chamber 26 facing the input chamber 27 into which the nozzle back pressure Pn is introduced. A pressure reducing valve 43 is arranged in the pipe 42 that is a flow path, and the zero point adjustment of the output pressure Pout can be performed from the outside of the electropneumatic conversion unit case 10 by adjusting the pressure reducing valve 43. It is characterized by

According to such a configuration, the supply air pressure Psup introduced into the bias chamber 26 facing the input chamber 27 into which the nozzle back pressure Pn of the pilot relay 3 is input is adjusted by the pressure reducing valve 43 to an arbitrary pressure. By adjusting the setting to, the zero point adjustment of the electrical input signal and the output pressure Pout can be performed from the outside of the electropneumatic conversion unit case 10 by a very simple adjustment operation.

Therefore, even in the positioner 1 installed on the site where the flameproof structure is required, the zero point adjustment can be extremely easily performed outside the flameproof type case 10, and even if the flameproof area is used. The zero point adjustment is extremely easy and reliable.

Here, in the positioner 1 in the above-described embodiment, the adjustment of the span adjustment or the like is performed by an appropriate adjustment such as adjustment of the connection position between the lever and the valve shaft for detecting the displacement of the control valve on the valve shaft. It is good to use an adjusting means.

A specific example in which the positioner 1 shown in FIG. 1 described above is applied to an electropneumatic positioner is shown in FIG. 2. The details are substantially the same as those shown in FIG. 1 and FIG. Yes, detailed description of each part is omitted. Here, the example shown in FIG. 2 shows a case where the body 10 of the pilot relay 3 is integrally assembled to the case 10 of the electropneumatic conversion unit 2.

Further, in FIG. 2, 50 is a drive unit of the control valve 5, 51 is a valve shaft thereof, and the movement of the valve shaft 51 moves inside the electropneumatic conversion unit 2 via a lever 52 having a span adjusting unit 52a. Is transmitted to the flapper 16 by a feedback system including a cam 53, a cam follower 54, a lever 55, and a spring 56.

FIG. 3 exemplifies a case in which the present invention is applied to a pneumatic positioner 60. Even in the case of such a pneumatic type, as with the electro-pneumatic positioner 1 described above, a zero point adjusting function is provided. Can be arbitrarily and easily adjusted by the pressure reducing valve 43 in the middle of the supply air pressure passage 42 to the bias chamber 26 of the pilot relay 3.

Here, in such a pneumatic positioner 60, a feedback system for transmitting the displacement of the valve shaft 51 is provided in the case 61, and a zero point adjusting means is also provided in a part thereof. Also in this case, an operation of opening the case 61 is required, and this has a great advantage that it can be omitted. In addition, there is a problem that the structure is complicated because the zero point adjustment can be performed by penetrating the case 61. In the present embodiment, such a problem can be solved. Is.

Further, according to the present invention, as a means for adjusting the zero point of the output pressure Pout by changing the bias in the pilot relay 3 described above, for example, a configuration as shown in FIG. 4 is adopted. It is easy to understand that it is good.

That is, the positioner 1 in this embodiment is such that the input chamber 27 as a nozzle back pressure chamber, the diaphragms 30 and 31 that define the nozzle back pressure chamber, and the diaphragms 30 and 31 are connected to each other. In the pilot relay 3 which has the poppet valve bodies 36 and 37 to operate, and outputs a required air pressure as the output pressure Pout by the operation of the poppet valve bodies 36 and 37, in the input chamber 27 A bias spring 80, which is an elastic member, that abuts the diaphragms 30 and 31 (piston 32, which is an area plate member) from the side is provided, and a bias adjusting screw 81 that increases or decreases the elastic force of the bias spring 80 is attached to the pilot relay 3 It may be provided on a part of the body 22 so as to be adjustable.

Reference numeral 82 in the drawing denotes a screw portion for screwing the adjusting screw 81 into the body 22, and 83 denotes a sealing material for sealing between the adjusting screw 81 and the opening portion of the body 22.

That is, according to such a configuration, the elastic force applied to the diaphragms 30 and 31 and the piston 32 by the bias spring 80 provided in the input chamber 27 to which the nozzle back pressure Pn of the pilot relay 3 is guided is applied. By adjusting and adjusting the bias adjusting screw 81 provided on the body 22 of the pilot relay 3, the elastic force on the diaphragm 30, 31 side can be arbitrarily set and adjusted, and the movement of the poppet valve bodies 36, 37 is required. It is possible to obtain a desired output pressure Pout by controlling the state.

Even with such a configuration, the zero point adjustment of the electrical input signal and the output pressure Pout in the electropneumatic converter 2 can be performed by an extremely simple adjustment operation from the outside of the electropneumatic converter case 10. It is easy to understand that the zero adjustment can be easily and reliably performed even in the explosion-proof area.

It is needless to say that the present invention is not limited to the structure of the embodiment described above, and that the shape, structure, etc. of each part can be appropriately modified and changed. For example, in the positioner 1 according to the present invention, it is preferable to use an adjusting means having an appropriate structure for adjusting the span.

Further, in the above-described embodiment, in addition to the pressure reducing valve 43 provided for zero point adjustment, zero point adjusting means is additionally provided in the electro-pneumatic conversion unit case 10 for initial setting. The invention is not limited to this, and it goes without saying that the means inside the case 10 may be omitted.

[0039]

As described above, the positioner according to the present invention has the bias chamber facing the nozzle back pressure chamber and the pilot relay for introducing the supply air pressure to the bias chamber. A pressure reducing valve was installed in the flow path for introducing air pressure into the bias chamber, and the zero point of the output pressure was adjusted by adjusting the pressure reducing valve. By adjusting the supply air pressure introduced into the bias chamber facing the nozzle back pressure chamber of the relay to an arbitrary pressure with the pressure reducing valve, the zero point adjustment of the output pressure is extremely easy from the outside of the electro-pneumatic conversion unit case. It can be performed by various mechanical configurations and adjustment operations, and even in the explosion-proof area, zero-point adjustment can be easily and reliably performed with various excellent practical effects.

According to the present invention, the nozzle back pressure chamber, the diaphragm defining the nozzle back pressure chamber, the poppet valve connected to the nozzle back pressure chamber to operate, and the pilot relay outputting the air pressure by the operation are provided. In the nozzle back pressure chamber, an elastic member that comes into contact with the diaphragm from the nozzle back pressure chamber side is provided, and a adjusting screw that increases or decreases the elastic force of this elastic member is provided in the body of the pilot relay. Despite this structure, the elastic force of the elastic member with respect to the diaphragm can be set and adjusted by adjusting the adjusting screw to adjust the zero point of the output pressure even in the explosion-proof area. In addition, it has various practical effects that can be performed from the outside of the electropneumatic conversion unit case by extremely simple adjustment operation.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a main part showing an embodiment of a positioner according to the present invention.

FIG. 2 is a schematic configuration diagram showing a specific example of an electropneumatic positioner to which the present invention is applied.

FIG. 3 is a schematic configuration diagram in which the present invention is applied to a pneumatic positioner.

FIG. 4 is a schematic configuration diagram of a main part showing another embodiment of the positioner according to the present invention.

FIG. 5 is a block diagram for explaining a schematic configuration of a positioner.

[Explanation of symbols]

 1 Valve Positioner 2 Electro-Pneumatic Converter 3 Pilot Relay 10 Explosion Proof Case 11 Electro-Pneumatic Converter 15 Nozzle Flapper 20 Supply Air Pressure Introduction Path (Piping) 21 Restrictor 22 Body (Pilot Relay Body) 23 Supply Air Pressure Chamber 24 Output Chamber 25 Atmosphere Communication chamber 26 Bias chamber 27 Input chamber (nozzle back pressure chamber) 32 Piston 36 Poppet valve body 37 Poppet valve body 39 Pipe for output pressure side 42 Pipe for supply air pressure introduction passage 43 Pressure reducing valve 60 Pneumatic positioner 80 Bias spring (elasticity) 81) Bias adjusting screw Psup Supply air pressure Pout Output pressure Pn Nozzle back pressure

Claims (2)

[Scope of utility model registration request] 1. A positioner having a bias chamber facing a nozzle back pressure chamber and having a pilot relay for introducing supply air pressure into the bias chamber, wherein a pressure reducing valve is provided in a supply air pressure introducing flow path to the bias chamber. Positioner that is characterized by doing. 2. A nozzle back pressure chamber, a diaphragm that defines the nozzle back pressure chamber, and a poppet valve that operates by being connected to the diaphragm. A pilot relay that outputs air pressure by operating the poppet valve is provided. In the positioner having the elastic member, the elastic member contacting the diaphragm from the nozzle back pressure chamber side is provided in the nozzle back pressure chamber, and the adjusting screw for increasing / decreasing the elastic force of the elastic member is provided in one of the bodies forming the pilot relay. Positioner characterized by being installed in the section.