JPH0448324Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Industrial application field) The present invention relates to an electropneumatic converter.

More specifically, the present invention relates to an automatic-manual changeover switch for an electro-pneumatic converter.

(Prior Art) FIG. 9 is a diagram illustrating the configuration of a conventional example that has been commonly used, and FIG. 10 is a diagram illustrating the configuration of the main part of FIG. 9.

In the figure, 1 is a torque motor to which an input signal current is input. 11 is a movable piece that is displaced in response to an input signal. Reference numeral 2 denotes a nozzle which is arranged opposite to one end of the movable piece 1 and constitutes a nozzle-flapper mechanism with one end of the movable piece. 3 is a pressure reducing valve 31
This is a control relay to which the supply air pressure Ps is supplied, amplifies the back pressure of the nozzle 2, and outputs the load output air pressure Pout. 4 is provided at the other end of the movable piece 11 and is the output air pressure of the control relay 3.
This is the feedback bellow where Pout is introduced.
5 is an automatic-manual changeover switch provided between the nozzle 2 and the control relay 3. Automatic-
The manual changeover switch 5 is shown in FIG. In FIG. 10, 51 is a block, and 52 is a block 51.
This is a switching chamber provided in the valve seat 53 and having a valve seat 53. The supply air pressure Ps is supplied to the switching chamber 52 via the throttle 54. 55 is a valve body that opens and closes the valve seat 53.
551 is O for sealing the switching chamber 52 and the valve body 55.
It's a ring. 56 is a communication hole provided between the throttle 54 and the valve seat 53 and connected to the control relay 3. 57 is a connection hole to the nozzle 2 provided on the opposite side of the communication hole 56 across the valve seat 53.

In the above configuration, the automatic-manual switching operation is performed by closing the valve seat 53 with the valve element 55 in the automatic-manual changeover switch 5 to change to the manual operation state, so that the supply pressure Ps to the changeover switch 5 is This becomes the signal pressure to the control relay 3. Therefore, by manually operating the pressure reducing valve 31, the output pressure of the control relay 3 can be manually operated. Next, in order to enter the automatic operation state, the valve seat 53 is opened by separating the valve body 55 from the valve seat 53. The back pressure of nozzle 2 is
6 becomes the signal pressure to the control relay 3. The device is therefore in automatic operation.

(Problem to be solved by the invention) However, in such a device, if you want to perform emergency exhaust such as when there is an abnormality in the plant equipment or the main body of the equipment, the valve body must be removed from the block, but it is not possible to do so immediately. Since it cannot be removed, there is a risk of not being able to make it in time in case of an emergency.

The present invention solves these problems.

An object of the present invention is to provide an inexpensive electro-pneumatic converter that has a simple configuration, is easy to perform automatic-manual switching operation, and is easy to maintain.

(Means for Solving the Problem) In order to achieve this objective, the present invention provides a drive that drives a flapper in response to the input current in an electro-pneumatic converter that controls the air output in response to the input current. means, a nozzle constituting a nozzle flapper mechanism provided opposite to one end of the flapper, a control relay for amplifying the back pressure of the nozzle and outputting it as output air pressure, and a pressure equal to the output air pressure of the control relay. a feedback bellow to which a force signal of the feedback bellow is inputted, a feedback means for feeding back a force signal of the feedback bellow to an input side of the driving means, a block provided between the nozzle and the control relay, and the block. a hole-shaped switching chamber provided in the block, to which supply pressure is supplied from one end side and having a valve seat; and a columnar valve that is slidably inserted in the axial direction from the other end of the switching chamber and opens and closes the valve seat. a sealing means provided between the body, the other end side of the switching chamber, and the valve body for sealing the switching chamber and the valve body; and an outer diameter of the valve body between the sealing means and the valve seat. a communication hole provided in the block between the one end of the block and the valve seat and communicating with the control relay; and an automatic/manual/emergency exhaust switching switch having the communication hole and a connection hole provided on the opposite side of the valve seat and connected to the nozzle. be.

(Function) In the above configuration, in order to perform the automatic-manual-emergency exhaust switching operation, in the automatic state, the valve body is slid in the axial direction to communicate the communication hole and the connection hole. In this state, the nozzle back pressure becomes an input signal to the control relay to automatically operate the device. To switch to the manual state, the valve element is slid in the axial direction and the valve element closes the valve seat of the switching chamber. The supply pressure becomes an input signal to the control relay, allowing manual operation of the device. To switch to the emergency exhaust state, the valve body is slid in the axial direction, the switching chamber is communicated with the outside through the gap, and the load air is exhausted from the control relay.

Examples will be described in detail below.

(Embodiment) FIG. 1 is an explanatory diagram of the main part configuration of an embodiment of the present invention.

In the figure, the same symbols as in FIGS. 9 and 10 indicate the same functions.

Reference numeral 58 denotes a columnar valve body that is slidably inserted in the axial direction from the other end of the switching chamber 52 and opens and closes the valve seat 53. Reference numeral 581 is an L-shaped conduction hole that is provided in the valve body 58 and opens at the shaft end and side surface of the valve body 58 on one end side. 54 is a throttle provided on the shaft end side of the conduction hole 581. Reference numeral 582 denotes an O-ring provided between the conduction hole 581 side of the valve body 58 and the switching chamber 52 to seal the switching chamber 52 and the valve body 58. 583 is provided between the opening side of the switching chamber 52 and the valve body 58;
This is an O-ring that seals the switching chamber 52 and the valve body 58. As shown in FIG. 2, reference numeral 584 is a gap portion provided in the threaded portion of the valve body 58 and cut out in a flat surface to form a gap with the switching chamber 52.

In the above configuration, during automatic operation, the supply pressure Ps passes through the throttle 54 as shown in FIG.
It passes through the conduction hole 581, the valve seat 53, and is supplied to the nozzle 2 through the connection hole 57. Nozzle 2 and movable piece 1
The associated nozzle back pressure P _N during 1 becomes an input signal to the control relay 3, and automatic operation is performed.

To switch to the manual operation state, as shown in FIG. 3, the valve body 58 is slid and the valve seat 53 is closed.
The input signal air pressure of control relay 3 is the supply pressure
Ps, the output air pressure of control relay 3
Pout becomes the pressure set by the pressure reducing valve 31 by operating the pressure reducing valve 31.

To switch to the emergency exhaust operation state, as shown in FIG. 4, the valve body 58 is slid so that the gap 584 protrudes from the block 51. The input signal air pressure to the control relay 3 becomes atmospheric pressure, and the air on the load side is exhausted from the control relay 3.

As a result, with a simple configuration, three states, automatic, manual, and emergency exhaust, can be set for the control relay that operates in both forward and reverse directions.

In particular, even when there is no pressure reducing valve 31 or when the electropneumatic positioner is separated from the main body, emergency exhaust can be performed in a short time, which is useful when there is an abnormality in plant equipment or the like.

Note that if a reverse operation control relay is used in which the output pressure Pout decreases as the nozzle back pressure increases, the operation will be opposite to the above. That is, the manual operation state in the above case becomes the emergency exhaust operation state, and the emergency exhaust operation state becomes the manual operation state.

Further, the movement of the valve body 58 is not limited to the rotation of the screw, but may be moved by a mechanism that slides in the longitudinal direction of the shaft.

Further, in this embodiment, a throttle 54 is attached to the tip of the valve body 58. Therefore, by pulling out the valve body 58 from the block 51, the portion of the throttle 54, which is generally prone to clogging, can be easily cleaned.

FIG. 5 is an explanatory view of the main part of another embodiment of the present invention, in which A is a front view and B is a side view.

In this embodiment, the gap portion 584a is formed by cutting the threaded portion of the valve body 58 into a V-groove.

FIG. 6 is an explanatory view of the main part of another embodiment of the present invention, in which A is a side view and B is a front view.

In this embodiment, a cutout groove (a V-groove is also possible) having a rectangular cross section is provided in the external opening portion of the switching chamber 52 to form the gap portion 584b.

FIG. 7 is a block diagram of another embodiment of the present invention.

In this embodiment, the flapper is electrically driven by a driving means 63. On the other hand, the displacement of the feedback bellows 4 is electrically detected and this detection signal is fed back to the input side of the driving means.

In the figure, 61 is a current-voltage converter that converts the input current signal Io into voltage, and 62 is a current-voltage converter 6.
An amplifier that amplifies the voltage from 1, 63 is an amplifier 6
A driving means for driving the flapper 11 by the voltage output from the flapper 2, in this case, as shown in FIG.
A piezoelectric actuator made of a piezoelectric element is used. 64 is a nozzle flapper mechanism, 5 is an automatic
3 is a control relay, A is a load, and 4 is a feedback bellow. Reference numeral 65 denotes a force-electric signal converter that converts the force of the feedback bellows 4 into an electric signal and feeds it back to the input side of the amplifier 62.

(Effects of the Invention) As explained above, the present invention provides an electro-pneumatic converter that controls air output in accordance with an input current, including a driving means for driving a flapper in response to an input current, and one end of the flapper. a nozzle that is provided opposite to and constitutes a nozzle flapper mechanism;
A control relay that amplifies the back pressure of the nozzle and outputs it as output air pressure, a feedback bellow that receives the same pressure as the output air pressure of the control relay, and a feedback bellow that transmits the force signal of the feedback bellow to the drive means. Feedback means for providing feedback to the input side; a block provided between the nozzle and the control relay; and a hole-shaped switching chamber provided in the block and supplied with supply pressure from one end of the block and having a valve seat. A columnar valve body is inserted freely in the axial direction from the other end of the switching chamber to open and close the valve seat, and a columnar valve body is provided between the other end of the switching chamber and the valve body and is connected to the switching chamber. A sealing means for sealing the valve body, a gap portion provided at the outer diameter portion of the valve body or the other end opening of the switching chamber between the sealing means and the valve seat, and forming a gap, and one end of the block. and the valve seat, a communication hole facing the block and communicating with the control relay, and a connection hole provided in the block and on the opposite side of the communication hole and the valve seat, and connected to the nozzle. An electro-pneumatic converter is constructed, which includes an automatic-manual-emergency exhaust switching switch.

As a result, with a simple configuration, the three states of automatic, manual, and emergency exhaust can be set for the control relay that operates in both forward and reverse directions.

In particular, even if there is no pressure reducing valve or the electro-pneumatic converter is far away, emergency exhaust can be performed in a short time.
This is useful when there is an abnormality in plant equipment, etc.

Therefore, according to the present invention, with a simple configuration, it is possible to easily switch between automatic, manual and emergency exhaust.
An inexpensive electro-pneumatic converter can be realized.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the main part of an embodiment of the present invention.
Figure 2 is an explanatory diagram of the main part configuration of Figure 1, where A is a plan view, B is a front view, C is a side view, Figures 3 and 4 are explanatory diagrams of the operation of Figure 1, and Figure 5 is FIG. 6 is an explanatory diagram of the main part of another embodiment of the present invention, in which A is a front view and B is a side view; FIG. is a front view, FIG. 7 is a block diagram of another embodiment of the present invention, FIG. 8 is an explanatory diagram of the main part configuration of FIG. 7, and FIG. 9 is a configuration diagram of a conventional example commonly used. Figure 10 is the 9th
FIG. 2 is an explanatory diagram of the main part configuration of the figure. 1... Torque motor, 11... Movable piece, 2...
Nozzle, 3...Control relay, 31...Pressure reducing valve, 4...Feedback bellow, 5...Auto-manual-emergency exhaust switching switch, 51...Block, 52...Switching chamber, 53...Valve seat , 54...Aperture, 56...Communication hole, 57...Connection hole, 58...
Valve body, 581... Conduction hole, 582, 583... O
Ring, 584...Gap portion, 61...Current-voltage converter, 6...Amplifier, 63...Driving means, 64
... Nozzle flapper mechanism, 65 ... Force-electrical signal converter.

Claims (1)

[Scope of utility model registration request] An electro-pneumatic converter that controls air output in accordance with an input current, comprising: a drive means for driving a flapper in response to an input current; a nozzle provided opposite to one end of the flapper and forming a nozzle flapper mechanism; , a control relay that amplifies the back pressure of the nozzle and outputs it as output air pressure, a feedback bellow to which the same pressure as the output air pressure of the control relay is input, and a force signal of the feedback bellow that is transmitted to the driving means. a block provided between the nozzle and the control relay; and a hole-shaped switching chamber provided in the block and supplied with supply pressure from one end side of the block and having a valve seat. and a columnar valve body that is inserted freely in the axial direction from the other end of the switching chamber to open and close the valve seat, and a columnar valve body that is provided between the other end of the switching chamber and the valve body and that is connected to the switching chamber. a sealing means for sealing the valve body; a gap portion forming a gap provided at the outer diameter portion of the valve body or the opening at the other end of the switching chamber between the sealing means and the valve seat; A communication hole provided in the block between one end and the valve seat and communicating with the control relay; and a connection provided in the block and on the opposite side of the communication hole and the valve seat and connected to the nozzle. Automatic-manual- with hole
An electro-pneumatic converter equipped with an emergency exhaust changeover switch.