JP6291330B2 - Air pressure conversion device - Google Patents

Description

  The present invention relates to an air pressure conversion device that converts an input air pressure into a predetermined air pressure and outputs the air pressure.

Conventionally, as this type of air pressure conversion device, a positioner whose internal configuration is shown in a block diagram in FIG. 8 is known (see, for example, Patent Document 1). In the figure, 1 is an I / F (interface) terminal, 2 is an electric circuit module including a CPU (Central Processing Unit), a memory, and the like, 3 is an electropneumatic converter, and 4 is a nozzle back from the electropneumatic converter 3. pressure P _N amplifies the pilot relay is supplied to the regulator valve 200 as an output air pressure Po (pneumatic amplifier), 5 is the angle sensor for detecting fed back to the electrical circuit module 2 of the CPU to the operating position of the regulator valve 200, these A positioner 100 is configured.

In the positioner 100, an input electrical signal I _IN (4 to 20 mA) is granted from the controller 300, i.e. when the input electric signal I _IN is supplied from the controller 300 to the I / F terminal 1, the electric circuit module 2 CPU Performs a control operation from the input electric signal I _IN and the feedback signal I _FB detected by the angle sensor 5, and supplies a current I 1 corresponding to the result to the electropneumatic converter 3. The electropneumatic converter 3 is supplied with compressed air pressure Ps air (high pressure instrument air) from the air pressure supply source, and the air pressure Ps of the instrument air is converted to the nozzle back pressure P _N corresponding to the current I1. And output to the pilot relay 4. Pilot relay 4, electrostatic amplifies the nozzle back pressure P _N from pneumatic converter 3, supplied to the regulating valve 200 as the output air pressure Po. Thus, is adjusted to a set opening the valve opening degree of the regulating valve 200 is shown in the input electric signal I _IN.

  In this positioner 100, there is a possibility that a trouble occurs when foreign matter is mixed in the supplied instrument air. For this reason, for example, in Patent Document 2, a filter for removing foreign matter is provided in the air circuit of the positioner.

JP-A-9-242706 JP 2005-233198 A JP 2013-011654 A

  However, the instrument air supplied to the positioner 100 may contain moisture. In the actual site, foreign matter and moisture are mixed in, and they enter the air circuit of the positioner, causing a temporary or permanent clogging inside and causing trouble. Foreign matter can be supplemented to some extent with a filter screen or the like, but moisture cannot be prevented from entering.

  Although it is conceivable to install a filter that can absorb moisture on the air circuit of the positioner, it is necessary to have a capacity for trapping moisture, so there is a large flow resistance on the air circuit, and the control performance of the positioner. Will be significantly reduced. In addition, the filter continues to trap moisture, thereby increasing the channel resistance and eventually blocking the channel. In addition, since it is installed in a part where the air flows, it is required to satisfy both a secure fixing method and maintainability, which causes an increase in product size and cost.

  For this reason, a filter for removing moisture is not currently provided, and troubles that are thought to be caused by moisture intrusion frequently occur in the field. During the verification of this trouble, the water that caused the trouble (water droplets caused by condensation) has evaporated or moved, and the reproducibility of the trouble is very low, and traces are difficult to remain. It makes identification difficult.

  The present invention has been made to solve such a problem, and an object of the present invention is to remove the foreign matter and to easily know the occurrence of the trouble caused by the intrusion of moisture. It is to provide a conversion device.

  In order to achieve such an object, the present invention includes a filter unit installed in a flow path through which the input air flows, in an air pressure conversion device that converts the air pressure of the input air to a predetermined air pressure and outputs the air pressure. The filter unit is a cylindrical filter screen for removing foreign substances contained in the air passing through the flow path, and detects water contained in the air passing through the flow path attached to the circumferential surface of the cylindrical filter screen. And a water wetness detection sheet whose color changes.

  According to the present invention, the foreign matter contained in the air passing through the flow path is removed by the cylindrical filter screen, and the water passing through the flow path by the water wetness detection sheet knows whether water is contained. Is possible. In the present invention, since only the trace of water contained in the air that has passed is known, the flow path resistance of the air circuit is not increased. This makes it possible to achieve both recording of water intrusion and prevention of entry of foreign matter.

  In the present invention, the water wetness detection sheet is a sheet that changes its color by detecting water contained in the air passing through the flow path, that is, condensation has occurred in the air passing through the flow path. This is a sheet that changes its color when it is detected, and even if the humidity in the air is high, the color does not change unless condensation occurs.

  According to the present invention, a cylindrical filter screen that removes foreign substances contained in the air passing through the flow path, and water contained in the air that is attached to the peripheral surface of the cylindrical filter screen and passes through the flow path. Since a filter unit equipped with a water wetting detection sheet that detects and changes its color is installed in the flow path through which the input air flows, water intrusion can be achieved without increasing the flow resistance of the air circuit. Both recording and prevention of entry of foreign matter can be achieved, and foreign matter can be removed and the occurrence of troubles caused by the entry of moisture can be easily known.

It is a figure which shows the inlet_port | entrance part of the instrumentation air of the positioner which is one Embodiment of the pneumatic converter which concerns on this invention. It is a figure which shows the stop ring used with this positioner. It is a disassembled perspective view of the filter unit used with this positioner. It is the front view and side view of a filter unit used with this positioner. It is a figure which shows the other example of the water leak detection sheet | seat used with this positioner. It is a disassembled perspective view which shows the structural example of the filter unit at the time of providing a viewing window. It is a figure corresponding to FIG. 1 at the time of providing a viewing window. It is a block diagram which shows the internal structure of a positioner.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a view showing a main part of an embodiment of an air pressure conversion device according to the present invention. FIG. 1 shows an instrument air inlet portion of a positioner as an embodiment of an air pressure conversion device according to the present invention.

  In FIG. 1, 10 is a case, 11 is a flow path of instrument air formed in the case 10, and 12 is a filter unit that is detachably installed at an inlet 11 a of the flow path 11. A fitting (piping joint) 14 is mounted at the inlet 11a of the flow path 11, that is, at the inlet 11a of the instrument air of the air pressure Ps, with a stop ring 13 that prevents the filter unit 12 from coming off.

  The stop ring 13 is a C-shaped ring as shown in FIG. 2, and after inserting the filter unit 12 to the step surface 11 b formed in the middle of the flow path 11 of the inlet 11 a of the flow path 11, the stop ring 13. The filter unit 12 is prevented from coming off by being fitted in a groove 11 c formed on the inner peripheral surface of the flow path 11 by reducing the diameter of the filter unit 11. Then, after fitting the stop ring 13 into the groove 11 c, the fitting 14 is screwed into the inlet 11 a of the flow path 11.

  In the present embodiment, the filter unit 12 includes a filter screen 15, a water wetting detection sheet 16, and a cylindrical case 17, as shown in an exploded perspective view of FIG.

  The filter screen 15 has a mesh-like body portion 15a that is cylindrical, and a bottom portion 15b that is formed to be a part of the body portion 15a. The bottom surface portion 15b is also mesh-shaped.

  The water wetness detection sheet 16 is formed in a cylindrical shape, and the inner diameter and width thereof are substantially equal to the outer diameter and width of the body portion 15a of the filter screen 15. This water wetting detection sheet 16 is a special sheet that changes its end face 16a and its surrounding color by capillary action when it comes into contact with water. If no condensation occurs even in high humidity in the air, the end face 16a and , The surrounding color will not change. In addition, since this kind of water wetness detection sheet | seat is explained in full detail, for example in patent document 3, description here is abbreviate | omitted.

  The cylindrical case 17 includes a cylindrical body portion 17a and a distal end portion 17b that is formed to be a part of the body portion 17a. The tip portion 17b is an opening. The inner diameter and width of the body portion 17a are substantially equal to the outer diameter and width of the water wetting detection sheet 16.

  In this filter unit 12, the water wetness detection sheet 16 is bonded or fitted to the inner peripheral surface of the body portion 17 a of the cylindrical case 17, and the filter is applied to the cylindrical case 17 to which the water wetness detection sheet 16 is bonded. The screen 15 is press-fitted, and the water wetting detection sheet 16 is positioned on the outer peripheral surface of the body portion 15 a of the filter screen 15.

  That is, as shown in FIG. 4, the filter unit 12 has a three-layer structure including a filter screen 15, a water wetting detection sheet 16, and a cylindrical case 17. The wetness detection sheet 16 is sandwiched between the filter screen 15 and the filter screen 15 to be attached.

  In the positioner in which the filter unit 12 is set at the inlet 11 a of the flow path 11, foreign matters contained in the air passing through the flow path 11 are removed by the filter screen 15. The foreign matter accumulates on the bottom surface portion 15 b of the filter screen 15. In addition, when water is contained in the air passing through the flow path 11, that is, when water droplets due to condensation are generated in the air passing through the flow path 11, if this water comes into contact with the water wetness detection sheet 16, a capillary is formed. Due to the thin tube phenomenon, the color of the end surface 16a of the water wetting detection sheet 16 and its surroundings changes.

  In this way, in the present embodiment, the foreign matter contained in the air passing through the flow path 11 is removed by the filter screen 15 and is contained in the air passing through the flow path 11 by the water wetness detection sheet 16. Water is detected. In this case, since the water wetting detection sheet 16 only changes the color of the end surface 16a and its surroundings due to the thin tube phenomenon, that is, only knows the trace of water contained in the air that has passed through, the air circuit. Without increasing the flow path resistance, it is possible to achieve both the recording of water intrusion and the prevention of entry of foreign matter.

  In the embodiment described above, it is confirmed whether or not water has passed through the end surface 16a of the water wetting detection sheet 16 and its surroundings. However, as shown in FIG. For example, a rectangular cutout 16b may be formed in a part of the 16 sheet surfaces, and it may be confirmed whether water has passed through the end face of the rectangular cutout 16b and its periphery. Further, as shown in FIG. 5 (b), a large number of round holes 16c are provided in the sheet surface of the water wetness detection sheet 16, and whether or not water has passed through the end surfaces of the large number of round holes 16c and in the vicinity thereof. You may make it confirm.

  In the above-described embodiment, when the end surface 16a of the water wetting detection sheet 16 and the surrounding color must be confirmed, the fitting 14 must be removed. For example, as shown in FIG. When the water wetness detection sheet 16 provided with the round hole 16c is used, as shown in FIG. 6, the square hole 17a is provided at a position facing the round hole 16c of the water wetness detection sheet 16 of the cylindrical case 17. In this way, as shown in FIG. 7, if the case 10 is provided with a viewing window 10a through which the round hole 16c of the water wetting detection sheet 16 can be seen from the square hole 17a, the water will be wet without removing the fitting 14. The end face of the round hole 16c of the detection sheet 16 and the surrounding color can be confirmed.

  Further, in the above-described embodiment, when checking the state of the foreign matter accumulated on the bottom surface portion 15b of the filter screen 15, the fitting 14 must be removed. For example, as shown in FIG. A square hole 17b is provided at a position facing the bottom surface portion 15b of the filter screen 15, and a viewing window 10b is provided in the case 10 so that the bottom surface portion 15b of the filter screen 15 can be viewed from the square hole 17b as shown in FIG. By doing so, it is possible to check the state of the foreign matter accumulated on the bottom surface portion 15b of the filter screen 15 without removing the fitting 14.

  In the above-described embodiment, the filter unit 12 is set at the inlet 11a of the flow path 11. However, the filter unit 12 does not necessarily have to be the inlet 11a of the flow path 11, and is more case than the inlet 11a of the flow path 11. You may make it set the filter unit 12 in the position which entered the inside of 10. In this case, if the viewing windows 10a and 10b as shown in FIG. 7 are provided at the set position, the water detection state by the water wetting detection sheet 16 and the filter screen 15 can be obtained without disassembling the positioner. It is possible to confirm the removal state of the foreign matter.

  As shown in FIG. 1, when the filter unit 12 is set at the inlet 11 a of the flow path 11, the water detection state by the water wetting detection sheet 16 and the foreign matter removal state by the filter screen 15 are confirmed simply by removing the fitting 14. In addition, the filter unit 12 can be easily replaced. Even if the stop ring 13 is broken, the fitting unit 14 further prevents the filter unit 12 from coming off. This realizes a positioner with a filter function that achieves both low-cost, good maintainability, high safety, recording of water intrusion, prevention of intrusion of foreign matter, and suppression of increase in flow resistance. It will be a thing.

  In the embodiment described above, the filter unit 12 has a three-layer structure including the filter screen 15, the water wetting detection sheet 16, and the cylindrical case 17, but a two-layer structure including the filter screen 15 and the water wetting detection sheet 16. It is good. In this case, the inner wall of the flow path 11 serves as the cylindrical case 17.

  In the above-described embodiment, the positioner has been described as an example. However, any device that converts the air pressure of the input air into a predetermined air pressure and outputs it may be used, and the same applies to a pressure reducing valve. it can.

  In the above-described embodiment, the water wetting detection sheet 16 uses a sheet that changes the color of the end surface and its periphery when water is detected. However, when water is detected, the color changes and characters appear. It may be a simple sheet.

[Extension of the embodiment]
The present invention has been described above with reference to the embodiment. However, the present invention is not limited to the above embodiment. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the technical idea of the present invention.

  DESCRIPTION OF SYMBOLS 10 ... Case, 10a, 10b ... Viewing window, 11 ... Flow path, 11a ... Inlet, 12 ... Filter unit, 13 ... Stop ring, 14 ... Fitting, 15 ... Filter screen, 16 ... Water leak detection sheet, 16a ... End surface 16b ... rectangular cutout, 16c ... round hole, 17 ... cylindrical case, 17a, 17b ... square hole, 100 ... positioner.

Claims (6)

In the air pressure conversion device that converts the air pressure of the input air to a predetermined air pressure and outputs it,
A filter unit installed in the flow path through which the input air flows;
The filter unit is
A cylindrical filter screen for removing foreign substances contained in the air passing through the flow path;
An air pressure conversion device comprising: a water wetness detection sheet that is attached to a peripheral surface of the cylindrical filter screen and detects water contained in air passing through the flow path and changes its color. In the air pressure conversion device according to claim 1,
The filter unit is
An air pressure conversion device comprising: a cylindrical case that covers the cylindrical filter screen to which the water wetness detection sheet is attached. In the air pressure conversion device according to claim 1,
The water wetness detection sheet has a notch in a part of the sheet surface. In the air pressure conversion device according to claim 1,
An air pressure conversion device characterized in that a viewing window is provided outside the flow path in which the filter unit is installed so that the state of the surface where the color of the water wetting detection sheet changes can be visually recognized. In the air pressure conversion device according to claim 1,
An air pressure conversion device characterized in that a viewing window is provided outside the flow path in which the filter unit is installed so that the state of the surface of the cylindrical filter screen from which foreign matter is removed can be visually recognized. In the air pressure conversion device according to claim 1,
The filter unit is
Removably installed at the input air inlet,
At the air inlet,
An air pressure conversion device, wherein a pipe joint is mounted with a stop ring interposed between the filter unit and the filter unit.

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