JP2808868B2 - Electro-pneumatic positioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an electropneumatic positioner in which an abnormal part can be easily found.

<Prior Art> FIG. 3 is an explanatory view of a configuration of a conventional example generally used conventionally.

In the figure, 1 is an input means, in which an input signal of 4 to 20 mA is used.

Reference numeral 2 denotes a control operation unit that compares an input signal with a signal from a valve opening detection unit 5 described later and outputs a control signal.

Reference numeral 3 denotes an air pressure generating means for generating an air pressure based on a control signal from the control calculating means 2.

Reference numeral 4 denotes a control valve which opens and closes a pipe through which a measurement fluid flows by air pressure from the air pressure generating means 3.

Numeral 5 is a valve opening detecting means which detects the valve opening of the control valve 4, converts it into a corresponding electric signal, and sends the signal to the control calculating means 2. In this case, a potentiometer, a rotary encoder, or the like is used, and the rotation angle of a lever that rotates as the control valve opens and closes is measured to detect the opening and closing degree of the valve.

Reference numeral 6 denotes a pressure detecting means for inputting an air signal from the air pressure generating means 3 and converting it into an electric signal.

Numeral 7 is a characteristic storage means for storing the relationship between the operating air pressure and the valve opening during normal operation of the control valve 4.

Numeral 8 denotes a comparing means, which is a valve opening detecting means 5 and a pressure detecting means 6
This is a means for comparing the signal from the controller with the characteristic stored in the characteristic storage means 7 and outputting an abnormal signal if the characteristic stored in the characteristic storage means 7 deviates from the normal range.

Reference numeral 9 denotes an alarm unit that performs an alarm sound or an alarm display based on an abnormal signal from the comparison unit 8.

In the above configuration, when an input signal of 4 to 20 mA is applied to the control operation means 2, a control signal corresponding to the input signal is output. The air pressure generating means 3 generates a corresponding air pressure based on a control signal from the control calculating means 2. By the air pressure from the air pressure generating means 3, the control valve 4 opens and closes a pipe through which the measurement fluid flows. The valve opening of the control valve 4 is detected by the valve opening detecting means 5, converted into a corresponding electric signal, collated with the input signal by the control calculating means 2, and
The control signal is sent to the air generating means 3. Hereinafter, the control valve 4 is controlled by this repetition.

Thus, for example, when impurities are caught between the valve plug of the control valve 4 and the guide ring, friction increases. To counter this friction, the relationship between the valve opening and the operating air pressure applied to the control valve 4 is increased. Deviates from the normal state. The comparing means 8 detects this, and an alarm is issued in the alarm means 9.

<Problems to be Solved by the Invention> However, in such a device, even if an abnormal signal is generated, it cannot be determined which of the control valve 4, the valve opening detecting means 5, and the pressure detecting means 6 is abnormal.

For example, even if the pressure detecting means 6 causes zero drift, an abnormal alarm is issued. For this reason, even if there is no problem in the control of the control valve 4, an abnormal alarm is issued and it is erroneously recognized as a trouble of the control valve 4.

 The present invention solves this problem.

An object of the present invention is to provide an electropneumatic positioner which can determine whether an abnormal point is a pressure detecting means, a valve opening detecting means, a control valve and a flow rate measuring means, and which can easily take appropriate measures.

<Means for Solving the Problems> In order to achieve this object, the present invention provides an electropneumatic positioner for controlling a valve opening of a control valve in accordance with an input signal, wherein a pressure detection for detecting an operation air pressure of the positioner is provided. Means, a valve opening detecting means for detecting a valve opening of the positioner, a flow detecting means for detecting a pipe flow rate controlled by the control valve, an operating air pressure and a valve opening during a normal operation of the control valve. Characteristic storage means for storing the relationship between the operating air pressure and the flow rate, and the relationship between the valve opening and the flow rate, the relationship between the operating air pressure and the valve opening during the adjustment. The relationship between the relationship between the operating air pressure and the flow rate and the relationship between the valve opening and the flow rate are deviated from each other. Abnormalities and judgment An abnormality in the relationship between the operating air pressure and the valve opening and an abnormality in the relationship between the valve opening and the flow rate is determined to be abnormal in the valve opening detecting means, and an abnormality in the relationship between the operating air pressure and the flow rate and the relationship between the valve opening and the flow rate. The electropneumatic positioner comprises a control valve or a comparison operation means for determining that the flowmeter is abnormal.

<Operation> In the above-described configuration, when an abnormality occurs in the apparatus, the comparison calculation unit determines the relationship between the relationship stored in the characteristic storage unit, the relationship between the operating air pressure and the valve opening during adjustment, and the relationship between the operating air pressure and the flow rate. If the relationship between the valve opening and the flow rate deviates from the comparison, it is determined that the pressure detecting means is abnormal due to the abnormality in the relationship between the operating air pressure and the valve opening and the relationship between the operating air pressure and the flow rate,
An abnormality in the relationship between the operating air pressure and the valve opening and an abnormality in the relationship between the valve opening and the flow rate is determined to be an abnormality in the valve opening detecting means. It is determined that the control valve or the flow meter is abnormal.

 Hereinafter, a detailed description will be given based on embodiments.

<Embodiment> FIG. 1 is an explanatory diagram of a main part configuration of an embodiment of the present invention.

 In the figure, the same symbols as those in FIG. 3 represent the same functions.

 Hereinafter, only differences from FIG. 3 will be described.

31 is a flow rate detecting means for detecting the flow rate of the pipe controlled by the control valve 4.

Numeral 32 is a characteristic storage means for storing the relationship between the operating air pressure and the valve opening during normal operation of the control valve 4, the relationship between the operating air pressure and the flow rate, and the relationship between the valve opening and the flow rate.

33 compares the relationship stored in the characteristic storage means 32, the relationship between the operating air pressure and the valve opening during adjustment, the relationship between the operating air pressure and the flow rate, and the relationship between the valve opening and the flow rate. When deviating, it is determined that the pressure detecting means is abnormal due to the abnormality of the relationship between the operating air pressure and the valve opening and the relationship between the operating air pressure and the flow rate, and the relationship between the operating air pressure and the valve opening degree, the valve opening degree and the flow rate are determined. Is an arithmetic operation means that determines an abnormality of the valve opening detecting means based on the abnormality of the relationship, and determines that the control valve or the flow meter is abnormal based on the abnormality of the relation between the operating air pressure and the flow rate and the abnormality of the relation between the valve opening degree and the flow rate. .

In the above configuration, when an abnormality occurs in the apparatus, the comparison calculation means 33 stores the relationship stored in the characteristic storage means 32, the relationship between the operating air pressure and the valve opening during adjustment, the relationship between the operating air pressure and the flow rate, and the valve. If the relationship between the opening and the flow rate deviates from the comparison, it is determined that the pressure detecting means is abnormal due to the abnormality in the relationship between the operating air pressure and the valve opening and the relationship between the operating air pressure and the flow rate. An abnormality in the relationship between the valve opening and the relationship between the valve opening and the flow rate is determined to be abnormal in the valve opening detecting means 5,
An abnormality in the control valve or the flow meter is determined based on the relationship between the operating air pressure and the flow rate and the relationship between the valve opening and the flow rate.

As a result, it is possible to determine whether the abnormal part is the pressure detecting means 6, the valve opening detecting means 5, the regulating valve 4, and the flow rate measuring means 31, and it is possible to obtain an apparatus which can easily take appropriate measures.

FIG. 2 is an explanatory view of a main part configuration of another embodiment of the present invention.

In this embodiment, a force-balancing electropneumatic positioner using a torque motor is used.

41 is a torque motor, 42 is a feedback element, and 43 is valve opening detecting means.

<Effects of the Invention> As described above, the present invention relates to an electropneumatic positioner that controls a valve opening degree of a control valve according to an input signal, wherein: a pressure detection unit that detects an operating air pressure of the positioner; Valve opening detection means for detecting a valve opening degree, flow rate detection means for detecting a pipe flow rate controlled by the control valve, and a relationship and operation between operating air pressure and valve opening degree during normal operation of the control valve Characteristic storage means for storing a relationship between air pressure and flow rate, and a relationship between valve opening degree and flow rate; and a relation stored in the characteristic storage means and a relation between operating air pressure and valve opening degree during adjustment, operating air pressure and flow rate. And the relationship between the valve opening and the flow rate is deviated by comparing the relationship between the operating air pressure and the valve opening and the relationship between the operating air pressure and the flow rate. Air pressure and valve open And the abnormality of the relationship between the valve opening and the flow rate, it is determined that the valve opening detecting means is abnormal, and the abnormality of the relationship between the operating air pressure and the flow rate and the relationship between the valve opening and the flow rate causes the control valve or the flow meter to fail. An electro-pneumatic positioner is provided, comprising comparison operation means for judging an abnormality.

As a result, it is possible to determine whether the abnormal part is the pressure detecting means 6, the valve opening detecting means 5, the regulating valve 4, and the flow rate measuring means 31, and it is possible to obtain an apparatus which can easily take appropriate measures.

Therefore, according to the present invention, it is possible to realize an electropneumatic positioner in which an abnormal point can be easily found.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a main portion of an embodiment of the present invention, FIG. 2 is an explanatory diagram of a main portion of another embodiment of the present invention, and FIG. 3 is a configuration of a conventional example generally used in the related art. FIG. DESCRIPTION OF SYMBOLS 1 ... Input means, 2 ... Control calculation means, 3 ... Air pressure generation means, 4 ... Control valve, 5 ... Valve opening degree detection means, 6 ...
Pressure detection means, 9 alarm means, 31 flow rate detection means,
32: characteristic storage means, 33: comparison operation means, 41: torque motor, 42: feedback element.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takeshi Nishijima 2-9-132 Nakamachi, Musashino City, Tokyo Inside Yokogawa Electric Corporation (72) Inventor Minoru Midorikawa 2-9-132 Nakamachi, Musashino City, Tokyo Next to Inside Kawa Electric Co., Ltd. (72) Inventor Yasuo Kasahara 2-93-2, Nakamachi, Musashino-shi, Tokyo Yokogawa Electric Co., Ltd. (72) Towa Sugawara 2-9-132, Nakamachi, Musashino-shi, Tokyo Yokogawa Electric (58) Investigated field (Int.Cl. ⁶ , DB name) F16K 37/00

Claims (1)

(57) [Claims] 1. An electropneumatic positioner for controlling a valve opening of a control valve in accordance with an input signal, a pressure detecting means for detecting an operating air pressure of the positioner, and a valve opening detecting for detecting a valve opening of the positioner. Means, a flow rate detecting means for detecting a pipe flow rate controlled by the control valve, a relationship between an operating air pressure and a valve opening degree, a relationship between an operating air pressure and a flow rate, and a valve opening degree during a normal operation of the control valve. Characteristic storage means for storing a relationship between the pressure and the flow rate; a relation between the operation air pressure and the valve opening during adjustment, a relation between the operation air pressure and the flow rate, a valve opening degree and a flow rate, and the relation stored in the characteristic storage means. If there is a deviation from the relationship between the operating air pressure and the valve opening, it is determined that the pressure detecting means is abnormal due to the abnormality in the relationship between the operating air pressure and the flow rate, and the relationship between the operating air pressure and the valve opening and the valve The relationship between opening and flow rate A comparison operation means for judging that the valve opening degree detecting means is abnormal due to an abnormality of the engagement, and judging that the control valve or the flow meter is abnormal due to the abnormality of the relation between the operating air pressure and the flow rate and the relation between the valve opening degree and the flow rate Electro-pneumatic positioner characterized by: