JP2022106235A - Valve and decompression valve using the same - Google Patents

Abstract

To provide a valve capable of ensuring a sliding property of a piston even with a simple structure, and a decompression valve using the same.SOLUTION: A valve VA is equipped with a valve body 18 that opens/closes a part between an inflow path 10 of a fluid S and an outflow path 12, a spring body 20 that seats the valve body 18 to a valve seat 22 by spring force, a rod 82 that contacts with the valve body 18, a piston 26 that presses the valve body 18 in a valve opening direction via the rod 82 to separate it from the valve seat 22, and a cylinder 28 that guides the rod 82 and the piston 26 so as to freely move. The piston 26 and the rod 82 are configured by separated bodies, and the piston 26 is configured by a spherical body.SELECTED DRAWING: Figure 5

Description

The present invention relates to a valve provided in a fluid passage to open and close the passage, and a pressure reducing valve using the valve.

Various valve devices are arranged in the fluid passage to regulate the pressure in the passage (for example, Patent Document 1). In a pressure reducing valve as in Patent Document 1, a valve shaft in which a rod is integrally connected to a cylindrical or disk-shaped piston is generally used, and the valve slides in the cylinder to cause a valve. It opens and closes the body. Therefore, when the piston is tilted in the cylinder, the slidability of the valve shaft deteriorates.

Japanese Unexamined Patent Publication No. 62-103717

In the device of Patent Document 1, the piston and the rod are connected by a hemispherical connecting portion to suppress the inclination of the piston. However, in the apparatus of Patent Document 1, the configuration of the valve shaft is complicated by providing the hemispherical connecting portion. Further, since the piston, the rod and the hemispherical connecting portion are integrally formed, it is difficult to manufacture.

An object of the present invention is to provide a valve capable of ensuring the slidability of a piston and a pressure reducing valve using the same while having a simple structure.

In order to achieve the above object, the valve of the present invention includes a valve body that opens and closes between an inflow path and an outflow path of a fluid, a spring body that seats the valve body on a valve seat by a spring force, and the valve body. It is provided with a rod that comes into contact with the rod, a piston that presses the valve body in the valve opening direction via the rod to separate the valve body from the valve seat, and a cylinder that movably guides the rod and the piston. The piston and the rod are made of separate bodies, and the piston is made of a sphere.

According to this configuration, the piston and the rod are composed of separate bodies, and the piston is composed of a sphere. As a result, even if the piston or rod is tilted with respect to the axial direction, the rotation of the spherical piston does not affect the sliding even if the piston is tilted. This can prevent the slidability of the piston from deteriorating. Moreover, since the piston and the rod are composed of separate bodies and only a spherical piston is used, the structure is simple.

In the present invention, a valve body drive chamber for moving the piston by the pressure of a fluid is further provided inside the cylinder, and a relief hole for releasing the pressure of the valve body drive chamber is formed in the piston, and a lower portion of the piston is formed. A weight portion may be provided in the piston, and one end opening of the relief hole may be formed in a non-contact portion with the rod in the lower portion of the piston. When the spherical piston rotates, the escape hole may be blocked by the inner surface of the cylinder.However, according to this configuration, since the piston is provided with a weight portion, the portion where the weight portion is provided is located downward. Positioned to. Therefore, it is possible to prevent the relief hole from being blocked by the upper end surface of the rod.

Further, instead of this, a recess may be formed on the inner peripheral surface of the cylinder to release the pressure of the valve body drive chamber. According to this configuration, even if the spherical piston rotates, the pressure in the valve body drive chamber can be released.

The pressure reducing valve of the present invention is a pressure reducing valve arranged in the main passage of the fluid to reduce the pressure on the primary side to the pressure on the secondary side, and includes a main valve body constituting the valve of the present invention. In this case, a pilot valve unit that opens and closes the main valve body may be further provided.

In a pilot-operated pressure reducing valve, the degree of opening and closing of the main valve body leads to the stability of the secondary pressure, so the slidability of the piston connected to the main valve body is an important factor in evaluating the performance of the pressure reducing valve. Is. According to the above configuration, it is possible to prevent the slidability of the piston from deteriorating, which is particularly effective for a pilot-operated pressure reducing valve.

According to the valve device and the pressure reducing valve of the present invention, the slidability of the piston can be ensured with a simple structure.

It is a vertical sectional view which shows the basic structure of the pressure reducing valve which is the object of this invention. It is a vertical sectional view schematically showing the state before decompression of the pressure reducing valve. It is a vertical sectional view schematically showing the pressure adjustment state of the pressure reducing valve. It is a vertical sectional view schematically showing the decompression holding state of the pressure reducing valve. It is a vertical sectional view which shows the main part of the valve which concerns on 1st Embodiment of this invention. It is a vertical sectional view which shows the main part of the valve which concerns on 2nd Embodiment of this invention. It is a flow figure which shows an example of the manufacturing process of the piston of the valve of 1st Embodiment. It is a flow figure which shows another example of the manufacturing process of the piston. It is a schematic diagram which shows still another example of the manufacturing process of the piston.

Prior to explaining the embodiment of the present invention, the pressure reducing valve used for the steam passage will be described. In various industries, steam is used as a heat medium from the viewpoint of cost, convenience and safety. The biggest merits are that the latent heat amount per unit weight is large and that the temperature can be kept constant by controlling the pressure.

When steam is used, instead of generating steam at each required pressure, high-pressure steam is generated in the boiler, and the steam is reduced to the required pressure according to the product and application. In that case, the automatic valve that keeps the steam pressure almost constant is the pressure reducing valve. The purpose of lowering the pressure is to lower the steam temperature and keep it at the desired heating temperature.

The basic principle of decompression is called the squeezing phenomenon, and when steam flows through the pipe, if the passage through which the steam flows is squeezed, the steam pressure on the downstream side of the squeezed part becomes lower. This is the depressurization of steam. If it is simply throttled, there is a method of fixing the valve to an intermediate opening or providing an orifice plate, but this method has a problem that the pressure changes when the flow rate changes. Therefore, even if the flow rate or the pressure on the primary side (pressure on the upstream side of the throttle point) changes, the energy of the fluid passing through the valve does not change so that the pressure on the secondary side (pressure on the downstream side of the throttle point) does not change. The pressure reducing valve is a valve that is set so that the valve opening is automatically changed by directly using.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a basic configuration of a pilot-operated pressure reducing valve which is a kind of pressure reducing valve using a valve device which is the object of the present invention. In FIG. 1, the pressure reducing valve is arranged in the main passage 1 through which steam S, which is a kind of fluid, flows. The casing 2 of the pressure reducing valve PRV is formed by connecting the main body case 4, the upper case 6 and the lower case 8. Inside the main body case 4, a primary side passage 10, a secondary side passage 12, and a valve chamber 14 between them are formed. The primary side passage 10 and the secondary side passage 12 form a part of the main passage 1 through which the steam S flows.

In the valve chamber 14, a valve holder 16 and a main valve body 18 sliding inside the valve holder 16 are arranged. The upper portion of the valve holder 16 is supported by a screw connection to the main body case 4. That is, the primary side passage 10 and the secondary side passage 12 form an inflow path and an outflow path for the main valve body 18, respectively. The upper portion of the valve holder 16 is supported by a screw connection to the main body case 4.

A spring force is applied to the main valve body 18 in the direction of contacting and closing the main valve seat 22 formed on the valve holder 16 by the main spring body 20 made of a coil spring. A main valve driving unit 24 for driving the main valve body 18 is arranged above the valve chamber 14. In the main valve drive unit 24, the piston 26 that abuts on the main valve body 18 is slidably inserted into the cylinder 28 supported by the main body case 4. The piston 26 is slidably inserted into the cylinder 28 supported by the main body case 4. Above the piston 26 is a main valve body drive chamber 27, which will be described later. The piston 26 is provided with a relief hole 29 for releasing the pressure of the main valve body drive chamber 27. The valve VA, which is the main valve device, is composed of the main valve body 18, the main spring body 20, the piston 26, and the cylinder 28.

The pilot valve unit 30 is arranged on the upper part of the upper case 6. That is, the upper case 6 forms the casing of the pilot valve unit 30. The pilot valve unit 30 has a pilot valve device 34 including a valve body 32, and a pilot valve drive unit 36 that opens and closes the pilot valve device 34. In the present embodiment, the valve body 32 is ball-shaped (spherical), but is not limited thereto. The pilot valve device 34 has a valve seat block 37, and a valve seat 40 is formed at the tip end portion (left end portion in FIG. 1). A valve opening 41 opened and closed by the valve body 32 is opened at the center of the valve seat 40.

A shaft member 42 is inserted into the valve seat block 37 so as to penetrate in the front-rear direction (left-right direction in FIG. 1). The tip portion 42a of the shaft member 42 is in contact with the valve body 32, and the rear end portion 42b faces the tip plate 38 described later of the pilot valve drive portion 36. The valve body 32 is pressed against the valve seat 40 by a first spring body 44 made of a coil spring. The first spring body 44 is interposed between the first spring body 44 and the first spring receiver 48 provided in the upper case 6.

The pilot valve drive unit 36 is a second spring body in which the tip plate 38 at the tip (left end in FIG. 1) is formed of a coil spring from the rear (right side in FIG. 1) to the front (left side in FIG. 1). Pressed by 54. The second spring body 54 is interposed between the tip member 56 in contact with the tip plate 38 and the second spring receiver 58 arranged inside the cover member 50. The cover member 50 is screwed to the upper case 6 (casing). A push rod 60 is arranged between the cover member 50 and the tip member 56, and the push rod 60 passes through the inner space of the second spring body 54.

The pilot valve drive unit 36 has a pressure adjusting means 49. The pressure adjusting means 49 has the tip plate 38 and the bellows 43, and retracts the second spring body 54 in the valve closing direction (rightward direction). That is, the pressure adjusting means 49 constitutes a valve closing force adding member that retracts the second spring body 54 in the valve closing direction against the spring force.

The tip portion 43a of the bellows 43 is connected to the tip plate 38, and the base end portion 43b of the bellows 43 is fixedly supported between the upper case 6 and the cover member 50. An adjustment handle 52 for pressure adjustment is rotatably screwed to the cover member 50.

A pilot chamber 62 for accommodating the first spring body 44 is arranged on the front side (left side) of the pilot valve device 34. The primary side passage 10 communicates with the pilot chamber 62 via a primary conduction path 64. A screen 66 for removing foreign matter is arranged in the pilot chamber 62. Further, a gangway 68 communicating with the valve opening 41 is formed on the downstream side of the valve body 32 in the pilot valve device 34. The pilot chamber 62 and the gangway 68 form an inflow path and an outflow path for the pilot valve unit 30, respectively. On the other hand, the secondary side passage 12 communicates with the pressure introduction chamber 70 in which the pressure applying means 49 is housed via the secondary conduction path 72.

Next, the operation of the above configuration will be described.
[Before decompression]
FIG. 2 shows before the start of the decompression operation, and the main valve body 18 is in the closed state. When the steam S is ventilated through the pressure reducing valve, the steam S reaches the pilot chamber 62 from the primary side passage 10 through the primary conduction path 64.

[Pressure adjustment]
When the adjusting handle 52 is rotated in the depressurizing direction (counterclockwise), the push rod 60 of the pressure applying means 49 moves forward (counterclockwise) as shown in FIG. Along with this, the bellows 43 extends and the tip plate 38 moves the shaft member 42 forward (to the left) to open the valve body 32. As a result, steam S flows through the outflow path (gangway) 68 and pushes down the piston 26 to open the main valve body 18. At this time, there is a slight gap G between the pressing plate 38 at the tip of the pressure applying means 49 and the back surface of the valve seat block 37. When the valve of the main valve body 18 is opened, the steam S of the pressure P1 in the primary side passage 10 flows into the secondary side passage 12 and is depressurized to the pressure P2.

[Maintaining decompression]
As shown in FIG. 4, a part of the steam S flowing into the secondary side passage 12 reaches the pressure introduction chamber 70 through the secondary conduction path 72. The bellows 43 of the pressure applying means 49 is compressed by the steam pressure in the pressure introduction chamber 70, and the tip plate 38 retracts to the right. As a result, the valve body 32 is moved in the valve closing direction by allowing the shaft member 42 to move backward (to the right). By adjusting the pressure of the main valve body drive chamber 27 in this way, the opening degree of the main valve body 18 is adjusted, and the pressure of the secondary side passage 12 is kept constant.

Next, the valve VA, which is a main part of the present invention, will be described with reference to the first embodiment of FIG. 5 and the second embodiment of FIG. As shown in FIG. 5, the piston 26 is composed of a sphere and has a rod 82 extending from the piston 26 toward the main valve body 18 (FIG. 1) and abutting on the main valve body 18. The piston 26 and the rod 82 are formed separately.

The spherical piston 26 moves in the axial direction AX of the rod 82 while rolling on the inner surface of the cylinder 28. In the present embodiment, the spherical piston 26 is provided with a first ventilation hole 80. The first ventilation hole 80 passes through the center point C of the piston 26 and extends through the piston 26. The first ventilation hole 80 constitutes a part of the above-mentioned relief hole 29 that communicates the main valve body drive chamber 27 with the space SP between the lower part of the piston 26 and the cylinder 28.

A weight portion 85 is provided at a position off the one end opening (lower end opening) 80a of the first ventilation hole 80 (relief hole) in the surface layer portion (lower part of FIG. 5) of the piston 26. The weight portion 85 is a portion having a heavier specific gravity than the residual portion 87. The weight portion 85 is located at the lower bottom portion when the piston 26 is in the upright posture.

FIGS. 7 to 9 show an example of a method for manufacturing the piston 26 of the present embodiment. In the example of FIG. 7, first, a hollow float ball 100 having a hole 100a is prepared. Next, a metal having a large specific density (weight portion 85) is poured into the float sphere 100 from the hole 100a. Further, a metal having a small specific density is poured from the hole 100a into the float sphere 100 (residual portion 87). Finally, a first vent hole 80 (FIG. 5) is formed in the remaining portion 87 by machining. As described above, the piston 26 of the present embodiment is manufactured. The float ball 100 may be removed from the weight portion 85 and the remaining portion 87 before machining the first ventilation hole 80 (FIG. 5).

In the example of FIG. 8, first, as a base material, a first member 102 (residual portion 87) made of a metal having a small specific gravity and a second member 104 (weight portion 85) made of a metal having a large specific density are prepared. Then, both 102 and 104 are joined. The joining is performed, for example, using an adhesive. However, the joining method is not limited to this. Next, the spherical piston 26 is formed by cutting out the base metal. Finally, the first ventilation hole 80 (FIG. 5) is formed in the remaining portion 87. As described above, the piston 26 of the present embodiment is manufactured.

In the example of FIG. 9, a residual portion 87 and a weight portion 85 molded into a shape that becomes a piston 26 when combined are prepared in advance. Such molding is performed, for example, by molding such as casting, forging, or the like. Next, the residual portion 87 and the weight portion 85 are joined. Joining is done, for example, by welding. Finally, the first ventilation hole 80 (FIG. 5) is formed in the remaining portion 87. As described above, the piston 26 of the present embodiment is manufactured.

As shown in FIG. 5, the rod 82 is a cylindrical rod-shaped member, and its axis AX coincides with the axis of the cylinder 28. Further, the axial center AX of the rod 82 passes through the center of the piston 26. The base end surface (upper end surface of FIG. 5) 82a of the rod 82 is in contact with the piston 26a, and the tip surface (lower end surface of FIG. 1) 82b is in contact with the main valve body 18. The rod 82 and the main valve body 18 are connected by a known structure. The piston 26 and the rod 82 are in tilting contact with each other in the axial direction AX of the piston 26. That is, the base end portion 82a of the rod 82 is in contact with the spherical surface of the spherical piston 26.

The cylinder 28 has a cylindrical guide portion 28a on which the piston 26 slides, a cylindrical rod holding portion 28b that holds the rod 82, and an annular connecting portion 28c that connects the guide portion 28a and the rod holding portion 28b. Have.

The guide portion 28a has a cylindrical shape extending from the connecting portion 28c to the side opposite to the main valve body 18 (upper side in FIG. 5), and slidably supports the piston 26 on the inner surface thereof. That is, the spherical piston 26 rolls with respect to the inner surface of the guide portion 28a. A second vent hole 84 is provided in the connecting portion 28c. The second ventilation holes 84 extend through the connecting portion 28c, and are provided at a plurality (for example, four) apart from each other in the circumferential direction. The second ventilation hole 84 constitutes a part of the above-mentioned relief hole 29.

The rod holding portion 28b has a cylindrical shape extending from the connecting portion 28c to the main valve body 18 side (lower side in FIG. 5), and slidably supports the rod 82 on the inner surface thereof. That is, the rod 82 slides with respect to the inner surface of the rod holding portion 28b. An annular groove 28ba is formed on the inner surface of the rod holding portion 28b, and a ring-shaped packing 86 is fitted in the groove 28ba. By providing such a packing 86, the inclination of the rod 82 is suppressed.

The packing 86 is, for example, a fluororesin. However, the material of the packing 86 is not limited to this. In the present embodiment, two packings 86 are provided along the axial direction AX of the rod 82, but the number of packings 86 may be one or three or more. Further, the packing 86 may be omitted.

In the piston 26, for example, the rod 82 may be tilted with respect to the axial center AX due to the influence of the fluid ejected from the valve opening when the main valve body 18 is opened. Along with this, if the piston 26 is also tilted, its slidability may deteriorate. According to the above configuration, the piston 26 and the rod 82 are made of separate bodies, and the piston 26 is made of a sphere. That is, the piston 26 and the rod 82 are in tilting contact with each other in the axial direction AX. As a result, even when the rod 82 is tilted with respect to the axial direction AX, even if the piston 26 is tilted due to the rotation of the spherical piston 26, the sliding is not affected. As a result, it is possible to prevent the slidability of the piston 26 from deteriorating.

In particular, in the pilot-operated pressure reducing valve PRV, the degree of opening and closing of the main valve body 18 leads to the stability of the secondary pressure, so the slidability of the piston 26 connected to the main valve body 18 evaluates the performance of the pressure reducing valve PRV. It is a heavy factor in doing so. With the above configuration, it is possible to prevent the slidability of the piston 26 from deteriorating, which is particularly effective for the pilot-operated pressure reducing valve PRV.

When the spherical piston 26 rotates, the inner wall of the cylinder 28 may block the relief hole 29 (first ventilation hole 80) provided in the piston 26. In the above configuration, since the weight portion 85 is provided at a position away from the one end opening 80a of the first ventilation hole 80 of the piston 26, the piston 26 is positioned so that the portion where the weight portion 85 is provided is downward. .. Therefore, it is possible to prevent the first ventilation hole 80 from being blocked by the inner wall of the cylinder 28.

Further, instead of the first ventilation hole 80 and the weight portion 85, as shown in the second embodiment of FIG. 6, a region including a contact portion with the piston 26 and its vicinity on the inner peripheral surface of the guide portion 28a of the cylinder 28. , One or a plurality of recesses 90 provided at intervals in the circumferential direction may be formed. The recess 90 is a part of a relief hole 29 for releasing the pressure of the valve body drive chamber 27. The size and number of the recess 90 are not specified as long as the valve body drive chamber 27 and the secondary side passage (outflow path) 12 can communicate with each other. For example, one long recess 90 may be provided in the axial direction AX of the rod 82, or a plurality of short recesses 90 may be provided side by side in the axial direction AX. By providing such a recess 90, even if the spherical piston 26 rotates, the pressure of the valve body drive chamber 27 can be released.

The present invention is not limited to the above embodiments, and various additions, changes, or deletions can be made without departing from the gist of the present invention. For example, the valve of the present invention can be applied to other than the main valve body 18 of the pressure reducing valve. Therefore, such things are also included within the scope of the present invention.

10 Primary side passage (inflow path)
12 Secondary side passage (outflow route)
18 Main valve body (valve body)
20 Main spring body (spring body)
22 Main valve seat (valve seat)
26 Piston 27 Main valve body drive chamber (valve body drive chamber)
28 Cylinder 29 Relief hole 30 Pilot valve unit 80 First ventilation hole (relief hole)
80a One end opening 82 Rod 85 Weight part 90 Recess (relief hole)
PRV pressure reducing valve S steam (fluid)
VA valve

Claims (5)

A valve body that opens and closes between the inflow path and the outflow path of the fluid,
A spring body that seats the valve body on the valve seat by spring force,
The rod in contact with the valve body and
A piston that presses the valve body in the valve opening direction via the rod to separate it from the valve seat.
A cylinder that movably guides the rod and the piston.
The piston and the rod are composed of separate bodies.
A valve in which the piston is composed of a sphere. The valve according to claim 1 is further provided with a valve body drive chamber for moving the piston by the pressure of a fluid inside the cylinder.
A relief hole for releasing the pressure of the valve body drive chamber is formed in the piston, and a relief hole is formed.
A weight portion is provided at the bottom of the piston.
A valve in which one end opening of the relief hole is formed in a portion of the lower part of the piston that is not in contact with the rod. The valve according to claim 1 is further provided with a valve body drive chamber for moving the piston by the pressure of a fluid inside the cylinder.
A valve having a recess formed on the inner peripheral surface of the cylinder to release the pressure of the valve body drive chamber. A pressure reducing valve located in the main passage of the fluid that reduces the pressure on the primary side to the pressure on the secondary side.
A pressure reducing valve including a main valve body constituting the valve according to any one of claims 1 to 3. The pressure reducing valve according to claim 4, further comprising a pilot valve unit for opening and closing the main valve body.

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