阅读说明：本技术 喷嘴挡板机构及阀门*** (Nozzle baffle mechanism and valve positioner ) 是由 井上和久 于 2019-06-25 设计创作，主要内容包括：本发明提供一种喷嘴挡板机构及阀门定位器,以防止喷嘴挡板部的污垢积蓄、堵塞,而不用进行定期维护、吹气等。在挡板(2)的与喷嘴(1)的喷口(1a)相对的位置上设置气流平滑部(21)。气流平滑部(21)具备：顶端部(21a),其突出至喷嘴(1)的喷口(1a)内部的流路中；扩径部(21b),其从顶端部(21a)向挡板(2)的与喷嘴(1)的喷口(1a)相对的表面扩径；以及外缘部(21c),其从扩径部(21b)的外端沿挡板(2)的长度方向平行地延伸。由此,从喷嘴(1)的喷口(1a)喷出的空气的流动方向变化和流路截面变化变缓,形成顺畅的流动,抑制高流速区域的湍流和低流速区域的产生,从而污垢不再积蓄、固化于喷嘴挡板部。(The invention provides a nozzle flapper mechanism and a valve positioner, which can prevent accumulation and blockage of dirt on a nozzle flapper without regular maintenance, air blowing, etc. An airflow smoothing section (21) is provided at a position of the baffle plate (2) facing the nozzle opening (1a) of the nozzle (1). The airflow smoothing unit (21) is provided with: a tip portion (21a) that protrudes into a flow path inside a nozzle (1a) of the nozzle (1); an enlarged diameter portion (21b) that is enlarged in diameter from the tip end portion (21a) to the surface of the baffle (2) that faces the nozzle opening (1a) of the nozzle (1); and an outer edge part (21c) extending in parallel in the longitudinal direction of the baffle (2) from the outer end of the enlarged diameter part (21 b). Thus, the change of the flow direction and the change of the flow path cross section of the air ejected from the ejection opening (1a) of the nozzle (1) are reduced, a smooth flow is formed, the generation of turbulence in a high flow velocity region and a low flow velocity region is suppressed, and the dirt is not accumulated and solidified on the nozzle baffle part.)

1. A nozzle flapper mechanism includes: a nozzle that ejects supplied air; and a shutter disposed with a swing end thereof close to the nozzle opening of the nozzle and configured to output a nozzle back pressure corresponding to a gap between the nozzle and the shutter as an air signal,

the nozzle flap mechanism is characterized in that,

the baffle plate is provided with an air flow smoothing portion at a position facing the nozzle opening of the nozzle, the air flow smoothing portion forming a smooth flow of air ejected from the nozzle opening of the nozzle,

the airflow smoothing unit includes:

a tip portion protruding into a flow path inside a spout of the nozzle;

an enlarged diameter portion that is enlarged in diameter from the distal end portion toward a surface of the baffle plate that faces the nozzle opening of the nozzle; and

an outer edge portion extending in parallel in a longitudinal direction of the baffle from an outer end of the enlarged diameter portion,

at least a part of the tip portion and the enlarged diameter portion is located inside a region facing the nozzle opening of the nozzle.

2. The nozzle-flapper mechanism of claim 1,

in the airflow smoothing section, an outer peripheral surface of at least one of the distal end portion and the diameter-enlarged portion is formed as a curved surface.

3. The nozzle-flapper mechanism of claim 1,

the nozzle opening of the nozzle expands in diameter as it approaches the baffle.

4. The nozzle-flapper mechanism of claim 3,

the nozzle opening of the nozzle is formed into a curved surface at a portion which expands in diameter as it approaches the baffle.

5. The nozzle-flapper mechanism of claim 1,

the airflow smoothing portion is provided as a member different from the baffle,

the airflow smoothing portion is attached to the baffle plate so that a gap between the nozzle opening of the nozzle and the airflow smoothing portion can be adjusted.

6. A valve positioner is characterized in that,

a nozzle shutter mechanism according to any one of claims 1 to 5.

Technical Field

The present invention relates to a nozzle flapper mechanism and a valve positioner that output a nozzle back pressure corresponding to a gap between a nozzle and a flapper as an air signal.

Background

Conventionally, a valve positioner is provided for an adjustment valve, and the valve opening degree of the adjustment valve is controlled by the valve positioner.

The valve positioner includes: a calculation unit which calculates a deviation between a valve opening setting value sent from a host device and an actual opening value fed back from a regulating valve, and generates an electric signal (MV) corresponding to the deviation as a control output; an electric idle conversion unit that converts the control output generated by the calculation unit into a nozzle back pressure (Pn) of a nozzle flapper mechanism that operates in accordance with air supplied from an air pressure supply source via a fixed throttle valve; and a pilot relay for amplifying the nozzle back pressure (air signal) converted by the electric-air conversion unit and outputting the amplified nozzle back pressure as an output air pressure to an operator of the regulator valve (see, for example, patent document 1).

FIG. 7 illustrates the main parts of a nozzle flapper mechanism used in a valve positioner. The nozzle flapper mechanism 100 includes a nozzle 1 that ejects air supplied through a fixed throttle 3, and a flapper 2 that swings about a fulcrum P. The flapper 2 is disposed with the swing end 2a close to the spout 1a of the nozzle 1.

In the nozzle flapper mechanism 100, a torque motor, not shown, is driven by an electric signal MV to change the position of the swing end 2a of the flapper 2. Thereby, the gap (interval) X between the nozzle 1 and the baffle 2 changes, the ejection rate of air from the ejection port 1a of the nozzle 1 changes, and the nozzle back pressure Pn changes.

Disclosure of Invention

[ problems to be solved by the invention ]

Fig. 8 shows a longitudinal sectional view of a peripheral portion of the nozzle flapper mechanism 100. Air is always ejected from the ejection port 1a of the nozzle 1, and a high flow velocity region where strong turbulence is generated by a change in the flow direction (90 ° bend) and a change in the flow path cross section and a low flow velocity region where the change in the flow direction is small are generated in the ejection port 1a of the nozzle 1. Fig. 9 shows a schematic view of a portion (nozzle baffle portion) surrounded by a dotted line in fig. 8. In fig. 9, a low flow velocity region generated in the ejection orifice 1a of the nozzle 1 is denoted as LA.

In the low flow velocity region LA, the dirt component having a higher density than air cannot follow a rapid change in the flow direction due to its inertia, and is accumulated and solidified in the nozzle baffle portion (the tip portion of the nozzle 1, the upper flat surface portion of the baffle 2) because the flow velocity is theoretically near 0. As a result, the actual value of the interval X and the flow of air change, and an accurate air signal (nozzle back pressure Pn) cannot be generated, thereby deteriorating controllability of the valve opening. When the amount of accumulated dirt is large, the nozzle baffle portion is clogged, resulting in poor control of the valve opening.

This requires regular maintenance (removal of dirt) to prevent accumulation and clogging of dirt in the nozzle baffle portion. In this case (see fig. 9), a sheet of paper or the like is inserted into the gap (space X) between the nozzle 1 and the flapper 2 to remove accumulated dirt, but depending on the installation location, maintenance may not be easily performed.

In addition, although it is considered to periodically blow air in order to prevent accumulation and clogging of dirt in the nozzle baffle portion, it is not preferable because it affects the nozzle back pressure (air signal). In addition, if dirt or deposits are fixed, they cannot be removed by air blowing. It is also conceivable to provide a cleaning mechanism to prevent and remove accumulation of dirt, but the mechanism affects the flow of air when operating, and thus the nozzle back pressure (air signal) changes. In addition, it is difficult to adopt the structure from the viewpoint of installation space.

As shown in patent document 2 (see fig. 10), the following configuration is conceivable: the baffle plate 2 is housed in a sealed case 4, a supply port 5a of an air pressure pipe 5 for supplying air pressure is provided in the sealed case 4, a nozzle 6 is disposed so that an open end 6a thereof is close to the baffle plate 2 and faces the same, and air inside the sealed case 4 is discharged to the outside of the sealed case 4 from the open end 6a of the nozzle 6. However, even with such a configuration, turbulence, pressure loss, and flow velocity change due to a rapid change in the cross-sectional area of the flow path occur in the supply port 5 a. In addition, in the portion introduced into the nozzle 6, since the cross-sectional area of the flow path changes rapidly, the same problem occurs, and therefore, the situation in which dirt is easily accumulated and solidified does not change.

The present invention has been made to solve the above-described problems, and an object thereof is to provide a nozzle flapper mechanism and a valve positioner that can prevent accumulation and clogging of dirt in a nozzle flapper portion without performing regular maintenance, air blowing, or the like.

[ means for solving the problems ]

To achieve the above object, a nozzle flapper mechanism (100) of the present invention includes: a nozzle (1) that ejects supplied air; and a baffle (2): the nozzle flapper mechanism (100) is characterized in that the flapper (2) is provided with an airflow smoothing section (21) at a position facing the nozzle orifice of the nozzle, the airflow smoothing section (21) forming a smooth flow of air ejected from the nozzle orifice, and the airflow smoothing section is provided with: a tip portion (21a) that protrudes into a flow path inside the nozzle opening of the nozzle; an expanding portion (21b) that expands the diameter from the tip portion to the surface of the baffle plate that faces the nozzle opening of the nozzle; and an outer edge portion (21c) extending from the outer end of the enlarged diameter portion in parallel to the longitudinal direction of the baffle, at least the tip end portion and a part of the enlarged diameter portion being located inside a region (S) facing the nozzle opening of the nozzle.

In the present invention, the baffle plate includes an airflow smoothing portion at a position facing the nozzle opening of the nozzle, the airflow smoothing portion includes a tip portion, an expanded diameter portion, and an outer edge portion, the tip portion protrudes into the flow path inside the nozzle opening of the nozzle, the expanded diameter portion expands in diameter from the tip portion to a surface of the baffle plate facing the nozzle opening of the nozzle, and the outer edge portion extends from an outer end of the expanded diameter portion in parallel to the longitudinal direction of the baffle plate. In the air flow smoothing portion, at least the tip end portion and a part of the diameter-enlarged portion are located inside a region facing the nozzle opening of the nozzle.

In the present invention, the air flow smoothing portion provided at a position of the baffle plate facing the nozzle opening of the nozzle can form a smooth flow of air ejected from the nozzle opening of the nozzle. Therefore, the change in the flow direction and the change in the flow path cross section of the nozzle orifice are reduced, and the occurrence of turbulence in the high flow velocity region and the low flow velocity region is suppressed, so that the dirt is not accumulated and solidified in the nozzle baffle portion.

In the present invention, the flow smoothing portion may have a tip portion and an enlarged diameter portion (all of the enlarged diameter portion) located inside a region facing the nozzle opening of the nozzle, or may have a tip portion, an enlarged diameter portion (all of the enlarged diameter portion), and an outer edge portion (a part or all of an outer edge portion) located inside a region facing the nozzle opening of the nozzle. Further, the airflow smoothing portion may be provided as a member different from the baffle plate, and the airflow smoothing portion provided as the different member may be attached to the baffle plate or the like so that the gap between the nozzle opening of the nozzle and the airflow smoothing portion can be adjusted.

In the above description, the components on the drawings corresponding to the components of the invention are indicated by parenthesized reference numerals, as an example.

[ Effect of the invention ]

As described above, according to the present invention, since the smooth flow of the air ejected from the nozzle opening of the nozzle can be formed by the air flow smoothing portion provided at the position of the baffle plate facing the nozzle opening of the nozzle, the change in the flow direction and the change in the flow path cross section of the nozzle are reduced, and the occurrence of the turbulent flow in the high flow velocity region and the low flow velocity region is suppressed, the low flow velocity region is not generated in the portion where the flow path rapidly changes, and the dirt does not continue and solidify in the nozzle baffle plate portion, and the accumulation and clogging of the nozzle baffle plate portion can be prevented without performing the regular maintenance, the air blowing, and the like.

Drawings

Fig. 1A is a view of the deposit on the upper planar portion of the baffle plate as viewed from above.

Fig. 1B is a view of the deposit on the upper planar portion of the baffle viewed obliquely.

Fig. 2A is a longitudinal sectional view of a main part of the nozzle flapper mechanism of embodiment 1.

Fig. 2B is a plan view showing the relationship between the area opposite to the nozzle orifice of the nozzle in the nozzle flapper mechanism of embodiment 1 and the air flow smoothing portion.

Fig. 3A is a longitudinal sectional view of a main part of the nozzle flapper mechanism of embodiment 2.

Fig. 3B is a plan view showing the relationship between the area opposite to the nozzle orifice of the nozzle in the nozzle flapper mechanism of embodiment 2 and the air flow smoothing portion.

Fig. 4A is a longitudinal sectional view of a main part of a nozzle flapper mechanism of embodiment 3.

Fig. 4B is a plan view showing the relationship between the area opposite to the nozzle orifice of the nozzle in the nozzle flapper mechanism of embodiment 3 and the air flow smoothing portion.

Fig. 5A is a longitudinal sectional view of a main part of the nozzle flapper mechanism of embodiment 4.

Fig. 5B is a plan view showing the relationship between the area opposite to the nozzle orifice of the nozzle in the nozzle flapper mechanism of embodiment 4 and the air flow smoothing portion.

Fig. 6 is a longitudinal sectional view of a main part of a nozzle flapper mechanism of embodiment 5.

Fig. 7 is a diagram showing a main part of a nozzle flapper mechanism used in the valve positioner.

Fig. 8 is a longitudinal sectional view of a peripheral portion of the nozzle flapper mechanism.

Fig. 9 is a schematic view of a portion (nozzle baffle portion) surrounded by a broken line in fig. 8.

Fig. 10 is a diagram showing a main part of the nozzle flapper mechanism shown in patent document 2.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, before proceeding to the description of the embodiments, the present invention will be described with respect to its gist.

[ in the eye ]

In the conventional nozzle flapper mechanism 100 (see fig. 8 and 9), a low flow velocity region LA is generated in the nozzle orifice 1a of the nozzle 1, and therefore, a dirty component having a higher density than air cannot follow a rapid change in the flow direction due to its inertia, and is accumulated and solidified in the nozzle flapper portion (the tip portion of the nozzle 1, the upper flat surface portion of the flapper 2) because the flow velocity is theoretically in the vicinity of 0.

In this case, when the deposit accumulated and solidified on the upper plane portion of the baffle 2 is accumulated to a certain extent, the shape becomes stable and further accumulation does not occur. When the deposition is performed until the shape of the deposition is stabilized, the inventors noticed that a smoother flow was formed than when the deposition was first started to be used. I.e. it is noted that the low flow rate region disappears. Then, it was confirmed by experiments and actual products that the deposits were deposited in a conical shape.

Fig. 1A shows a view of the deposit on the upper planar portion of the baffle plate 2 as viewed from above, and fig. 1B shows a view of the deposit on the upper planar portion of the baffle plate 2 as viewed obliquely. In this way, deposits on the upper flat surface portion of the baffle 2 are finally deposited in a conical shape.

Because of this, the inventors have obtained the following findings: if the position of the baffle 2 facing the nozzle orifice 1a of the nozzle 1 is shaped like a conical deposit, a smooth flow of air ejected from the nozzle orifice 1a of the nozzle 1 is formed, and a low flow velocity region is eliminated.

Embodiments 1 to 5 described below are based on such a point of view, and in order to distinguish the conventional nozzle shutter mechanism 100, the nozzle shutter mechanisms 100 of embodiments 1 to 5 are 100A _1 to 100A _5, and the conventional nozzle shutter mechanism 100 is 100B.

[ embodiment mode 1 ]

Fig. 2A is a longitudinal sectional view of a main part of the nozzle flapper mechanism 100(100A _1) of embodiment 1. In the nozzle flapper mechanism 100A _1, the flapper 2 is formed with an air flow smoothing portion 21(21_1) at a position facing the ejection port 1a of the nozzle 1, and the air flow smoothing portion 21(21_1) forms a smooth flow of air ejected from the ejection port 1a of the nozzle 1.

The airflow smoothing section 21_1 has the same shape (conical shape) as the deposit shown in fig. 1A, B, and includes: a tip portion 21a protruding into the flow path inside the nozzle orifice 1a of the nozzle 1; an enlarged diameter portion 21b that is enlarged in diameter from the distal end portion 21a toward the surface of the baffle 2 facing the nozzle opening 1a of the nozzle 1; and an outer edge portion 21c extending in parallel in the longitudinal direction of the baffle 2 from the outer end of the enlarged diameter portion 21 b.

In the airflow smoothing portion 21_1, the tip portion 21a, the diameter-enlarged portion 21b, and the outer edge portion 21c are located inside the region S facing the nozzle opening 1a of the nozzle 1. That is, as shown in fig. 2B, the distal end portion 21a is located in the center of the region S facing the nozzle orifice 1a of the nozzle 1, the enlarged diameter portion 21B is located in the region S so as to surround the distal end portion 21a, and the outer edge portion 21c is located in the region S so as to surround the enlarged diameter portion 21B. In this example, the distal end portion 21a is formed in a circular shape.

In the nozzle flapper mechanism 100A _1, the smooth flow of the air ejected from the ejection port 1a of the nozzle 1 can be formed by the air flow smoothing portion 21_1 provided at the position of the flapper 2 facing the ejection port 1a of the nozzle 1. Therefore, the change in the flow direction and the change in the flow path cross section of the nozzle orifice 1a of the nozzle 1 are reduced, and the occurrence of turbulence in the high flow velocity region and the low flow velocity region is suppressed, so that the dirt is not accumulated and solidified in the nozzle baffle portion.

This prevents accumulation and clogging of dirt in the nozzle baffle portion without performing regular maintenance, air blowing, and the like. Further, the basic function of the nozzle flapper is not affected, new structures and parts such as air blowing and cleaning mechanisms are not required, and the processing shape can be changed little, so that the influence on the cost is minimized.

[ embodiment 2 ]

Fig. 3A is a longitudinal sectional view of a main part of a nozzle flapper mechanism 100(100A _2) of embodiment 2. In the nozzle flapper mechanism 100A _2, the diameter of the nozzle orifice 1a of the nozzle 1 increases as it approaches the flapper 2. Further, the baffle 2 has an airflow smoothing portion 21(21_2) formed at a position facing the discharge port 1a of the nozzle 1, and the airflow smoothing portion 21(21_2) forms a smooth flow of the air discharged from the discharge port 1a of the nozzle 1. In fig. 3A, 1a1 denotes the inner edge of the spout 1a, and 1a2 denotes the outer edge of the spout 1 a.

The airflow smoothing section 21_2 has the same shape (conical shape) as the deposit shown in fig. 1A, B, and includes: a tip portion 21a protruding into the flow path inside the nozzle orifice 1a of the nozzle 1; an enlarged diameter portion 21b that is enlarged in diameter from the distal end portion 21a toward the surface of the baffle 2 facing the nozzle opening 1a of the nozzle 1; and an outer edge portion 21c extending in parallel in the longitudinal direction of the baffle 2 from the outer end of the enlarged diameter portion 21 b.

In the airflow smoothing portion 21_2, the tip portion 21a, the diameter-enlarged portion 21b, and the outer edge portion 21c are located inside the region S facing the nozzle opening 1a of the nozzle 1. That is, as shown in fig. 3B, the tip portion 21a is located in the center of the region S facing the nozzle orifice 1a of the nozzle 1, the enlarged diameter portion 21B is located in the region S so as to surround the tip portion 21a, and the outer edge portion 21c is located in the region S so as to surround the enlarged diameter portion 21B. In this example, the distal end portion 21a is pointed.

In this nozzle flapper mechanism 100A _2 as well, similarly to the nozzle flapper mechanism 100A _1 of embodiment 1, a smooth flow of air ejected from the ejection port 1a of the nozzle 1 can be formed by the air flow smoothing portion 21_2 provided at a position of the flapper 2 facing the ejection port 1a of the nozzle 1. In this case, the diameter of the nozzle opening 1a of the nozzle 1 increases as it approaches the baffle 2, and therefore, a smoother air flow can be formed. Therefore, since the change in the flow direction and the change in the flow path cross section of the nozzle orifice 1a of the nozzle 1 are reduced and the occurrence of turbulence in the high flow velocity region and the low flow velocity region is suppressed, the dirt is not accumulated or solidified in the nozzle flapper portion, and the same effect as that of the nozzle flapper mechanism 100A _1 of embodiment 1 can be obtained.

[ embodiment 3 ]

Fig. 4A is a longitudinal sectional view of a main part of a nozzle flapper mechanism 100(100A _3) of embodiment 3. In the nozzle flapper mechanism 100A _3, the spout port 1a of the nozzle 1 expands in diameter as it comes closer to the flapper 2, and the inner edge 1a1 of the spout port 1a and the outer edge 1a2 are connected in an R shape. Further, the baffle 2 has an airflow smoothing portion 21(21_3) formed at a position facing the discharge port 1a of the nozzle 1, and the airflow smoothing portion 21(21_3) forms a smooth flow of the air discharged from the discharge port 1a of the nozzle 1.

The airflow smoothing unit 21_3 includes: a tip portion 21a protruding into the flow path inside the nozzle orifice 1a of the nozzle 1; an enlarged diameter portion 21b that is enlarged in diameter from the distal end portion 21a toward the surface of the baffle 2 facing the nozzle opening 1a of the nozzle 1; and an outer edge portion 21c extending in parallel in the longitudinal direction of the baffle 2 from the outer end of the enlarged diameter portion 21b, the tip portion 21a and the outer edge portion 21c being set in a lofted shape continuous with each other by an arbitrary curved surface.

In the airflow smoothing portion 21_3, the tip portion 21a and the diameter-enlarged portion 21b are located inside the region S facing the nozzle opening 1a of the nozzle 1. That is, as shown in fig. 4B, the tip portion 21a is located in the center of the region S facing the nozzle orifice 1a of the nozzle 1, and the diameter-enlarged portion 21B is located in the region S so as to surround the periphery of the tip portion 21 a. In this example, the distal end portion 21a is formed in a circular shape. Further, the outer edge 21c surrounding the expanded diameter portion 21b is not located in the region S.

In this nozzle flapper mechanism 100A _3 as well, similarly to the nozzle flapper mechanism 100A _1 of embodiment 1, a smooth flow of air ejected from the ejection port 1a of the nozzle 1 can be formed by the air flow smoothing portion 21_3 provided at a position of the flapper 2 facing the ejection port 1a of the nozzle 1. In this case, the nozzle opening 1a of the nozzle 1 is expanded in diameter as it approaches the baffle 2, and the inner edge 1a1 of the nozzle opening 1a and the outer edge 1a2 are connected in an R shape, so that a smoother air flow can be formed. Therefore, since the change in the flow direction and the change in the flow path cross section of the nozzle orifice 1a of the nozzle 1 are reduced and the occurrence of turbulence in the high flow velocity region and the low flow velocity region is suppressed, the dirt is not accumulated or solidified in the nozzle flapper portion, and the same effect as that of the nozzle flapper mechanism 100A _1 of embodiment 1 can be obtained.

[ embodiment 4 ]

Fig. 5A is a longitudinal sectional view of a main part of a nozzle flapper mechanism 100(100A _4) of embodiment 4. In the nozzle flapper mechanism 100A _4, the nozzle orifice 1a of the nozzle 1 expands in diameter as it comes closer to the flapper 2, and the inner edge 1a1 and the outer edge 1a2 of the nozzle orifice 1a are connected in a bell mouth shape. Further, the baffle 2 has an airflow smoothing portion 21(21_4) formed at a position facing the discharge port 1a of the nozzle 1, and the airflow smoothing portion 21(21_4) forms a smooth flow of the air discharged from the discharge port 1a of the nozzle 1.

The airflow smoothing unit 21_4 includes: a tip portion 21a protruding into the flow path inside the nozzle orifice 1a of the nozzle 1; an enlarged diameter portion 21b that is enlarged in diameter from the tip portion 21a toward the surface 6 of the baffle 2 facing the nozzle opening 1a of the nozzle 1; and an outer edge portion 21c extending in parallel in the longitudinal direction of the baffle 2 from the outer end of the enlarged diameter portion 21b, the tip portion 21a and the outer edge portion 21c being set in a lofted shape in which they are connected to each other by a curved surface.

In the airflow smoothing portion 21_4, the tip portion 21a, the diameter-enlarged portion 21b, and the outer edge portion 21c are located inside the region S facing the nozzle opening 1a of the nozzle 1. That is, as shown in fig. 5B, the tip portion 21a is located in the center of the region S facing the nozzle orifice 1a of the nozzle 1, the enlarged diameter portion 21B is located in the region S so as to surround the tip portion 21a, and the outer edge portion 21c is located in the region S so as to surround the enlarged diameter portion 21B. In this example, the distal end portion 21a is formed in a circular shape.

In this nozzle flapper mechanism 100A _4 as well, similarly to the nozzle flapper mechanism 100A _1 of embodiment 1, a smooth flow of air ejected from the ejection port 1a of the nozzle 1 can be formed by the air flow smoothing portion 21_4 provided at a position of the flapper 2 facing the ejection port 1a of the nozzle 1. In this case, the nozzle opening 1a of the nozzle 1 is expanded in diameter as it approaches the baffle 2, and the inner edge 1a1 of the nozzle opening 1a and the outer edge 1a2 are connected in a bell mouth shape, so that a smoother air flow can be formed. Therefore, since the change in the flow direction and the change in the flow path cross section of the nozzle orifice 1a of the nozzle 1 are reduced and the occurrence of turbulence in the high flow velocity region and the low flow velocity region is suppressed, the dirt is not accumulated or solidified in the nozzle flapper portion, and the same effect as that of the nozzle flapper mechanism 100A _1 of embodiment 1 can be obtained.

[ embodiment 5 ]

Fig. 6 is a longitudinal sectional view of a main part of a nozzle flapper mechanism 100(100A _5) according to embodiment 5. In the nozzle flapper mechanism 100A _5, the airflow smoothing portion 21(21_5) is provided as a member different from the flapper 2, and the airflow smoothing portion 21_5 provided as a different member is attached to the flapper 2 so that the gap between the ejection port 1a of the nozzle 1 and the airflow smoothing portion 21_5 can be adjusted.

Specifically, a trunk portion 21d is provided as an airflow smoothing member 21 'below the airflow smoothing portion 21_5, and the trunk portion 21d of the airflow smoothing member 21' is screwed to the baffle plate 2 so as to be freely advanced and retracted in the axial direction of the nozzle 1. The other configuration is the same as the nozzle shutter mechanism 100A _1 of embodiment 1.

In the above embodiment, in the airflow smoothing portion 21, the tip end portion 21a and a part of the diameter-enlarged portion 21b may be located inside the region S facing the nozzle opening 1a of the nozzle 1, or the tip end portion 21a, the diameter-enlarged portion 21b (the entire diameter-enlarged portion 21b), and a part of the outer edge portion 21c may be located inside the region S facing the nozzle opening 1a of the nozzle 1.

In the above-described embodiment, the nozzle flapper mechanism incorporated in the valve positioner has been described as an example, but the present invention is not limited to the valve positioner, and can be used in the entire air control device (pressure flow control).

[ extension of embodiment ]

The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above embodiments. Various modifications that can be understood by those skilled in the art can be made in the configuration and detail of the present invention within the scope of the technical idea of the present invention.

Description of the symbols

1 … nozzle, 1a … nozzle, 2 … baffle, 2a … swing end, 21(21_1 to 21_5) … airflow smoothing part, 21a … top end part, 21b … diameter expanding part, 21c … outer edge part, 21' … airflow smoothing component, X … gap, Pn … nozzle back pressure, S … domain, 100(100A _1 to 100A _5) … nozzle baffle mechanism and 200 … valve positioner.