Valve device

Abstract

To provide a valve device that allows for easy installation of packing, which is a consumable part. [Solution] The valve device 1 controls the flow of fluid 20 by opening and closing an internal flow path 23 between a fluid inlet passage 21 and an outlet passage 22. It comprises a valve body 2 and a stem unit 3 that is detachable from the valve body 2. The stem unit 3 comprises a stem 4 whose tip opens and closes the internal flow path 23, a stem holder 6, a packing 7 inserted into the stem 4, and a first stem guide 8 mounted on the stem holder 6 with the packing 7 in between. The stem holder 6 has a second stem guide 11 at its lower end that guides the stem 4. A packing mounting portion 12 is provided above the second stem guide 11. An inclined guide surface 13 is formed continuously above the packing mounting portion 12 and moves away from the stem 4 as it moves upward.

Description

Technical Field

[0001] The present invention relates to a valve device that facilitates the assembly and replacement of a packing, which is a consumable part.

Background Art

[0002] Conventionally, various valve devices have been proposed for fluid control. For example, according to the description of Patent Document 1, a valve has four components: a valve body, an actuator, a yoke, and a bonnet between them. The valve body is provided with an inlet, an inlet passage, an outlet, and an outlet passage, and a valve seat is provided between the inlet passage and the outlet passage. A valve element having a contact surface that abuts and separates from the valve seat is provided vertically, and the valve element is formed on the lower tip side of the stem. The stem is connected to a shaft that is the axis of the actuator and is driven up and down by the actuator.

[0003] The bonnet is attached to the upper part of the valve body by a bonnet nut, the upper part of the bonnet is attached with a yoke, and an actuator is attached to the upper end of the yoke.

[0004] Inside the bonnet, a through-hole through which the stem passes is formed, and a gland packing through which the stem is inserted is provided therein. A washer is provided on the lower surface side of the gland packing, and an O-ring holder is provided on the upper surface side of the gland packing. The washer and the O-ring holder are made of metal, and a coating layer same as that of a fluororesin-based resin is provided on their surfaces. The resin coating layer is in close contact with the outer peripheral surface of the stem and the inner peripheral surface of the inner concave portion of the bonnet. Thereby, sealing performance is ensured, and the aging deterioration of the gland packing is reduced due to the opening and closing of high-pressure fluid over time.

[0005] According to this, the flow of fluid from the inlet passage to the outlet passage can be allowed or blocked, and fluid control can be performed.

Prior Art Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-159479 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, in the conventional example shown in Patent Document 1, a gland packing through which the stem is inserted is provided to prevent fluid leakage, a hinge is provided on the lower side, and an O-ring holder is provided on the upper side. The gland packing requires adjustment of the tightening amount during assembly and when replacing parts, which presents challenges in terms of workability. The gland packing is a consumable part and needs to be replaced after the valve device has been driven for a certain period of time, and each time this is done, a certain amount of assembly work is required, which is a problem.

[0008] The purpose of this invention is to solve the problems of the past and to provide a valve device that allows for easy installation of packing, which is a consumable part. [Means for solving the problem]

[0009] A valve device according to an aspect of the present invention is a valve device that controls the flow of a fluid by opening and closing an internal flow path between a fluid inlet passage and an outlet passage, comprising: an inlet passage; an outlet passage; a valve body in which the internal flow path is formed; and a stem unit detachable from the valve body, wherein when the bottom surface of the valve body is installed horizontally, the stem unit is mounted vertically upward relative to the valve body, and the stem unit comprises: a stem whose tip is for opening and closing the internal flow path; a stem holder installed on the valve body into which the stem is inserted; and a predetermined direction in which the stem extends. The stem holder comprises a packing having a packing width and being mounted on the stem holder, and a first stem guide inserted into the stem and mounted on the stem holder with the packing in between, wherein the stem holder has a second stem guide which is an opening hole at its lower end for guiding the stem, a packing mounting portion formed on the upper side of the second stem guide, and an inclined guide surface formed continuously on the upper side of the packing mounting portion which moves away from the stem as it goes upward, the packing is mounted sandwiched between the first stem guide and the second stem guide, and the stem operates guided by the first stem guide, the packing, and the second stem guide.

[0010] According to this design, the valve device operates with the stem guided by a first stem guide, a packing, and a second stem guide within the stem holder. Therefore, it has a sealing effect that prevents fluid leakage and can operate stably. In addition, the packing is guided by an inclined guide surface when it is installed in the stem holder, so it can be easily installed. Furthermore, since the packing is sandwiched between the first stem guide and the stem holder within the stem holder, it is possible to prevent packing fragments from scattering into the valve device if the packing is damaged.

[0011] Furthermore, the valve device may also include an air cylinder for operating the stem and a valve holder connected to the air cylinder and detachable from the valve body, wherein the stem holder has a flange formed on its outer circumference, and when the stem unit is oriented vertically, the stem unit is installed with a gasket in between the lower surface of the flange of the stem holder and the valve body, and the valve holder is attached to the valve body in contact with the upper surface of the flange of the stem holder.

[0012] In this case, the stem unit is installed with a gasket in between the lower surface of the flange portion of the stem holder and the valve body, thereby preventing fluid from leaking out through the gap between the stem holder and the valve body.

[0013] Furthermore, the valve device may include a packing shelf portion formed at the boundary with the second stem guide in a direction intersecting the direction in which the stem is inserted, the inclined guide surface guides the packing so that the packing can be mounted to the packing mounting portion when the packing is mounted on the stem and attached to the stem holder, and the packing shelf portion may lock the packing so that the packing can be separated from the stem and the packing when the stem is pulled out toward the tip of the stem while the packing is mounted to the packing mounting portion.

[0014] In this case, the inclined guide surface guides the packing when it is inserted into the stem and mounted on the stem holder, making it easy to mount the packing to the packing mounting section. Furthermore, when the stem is removed from the mounting section toward the tip of the stem, the packing shelf locks the packing in place, allowing the packing to be separated from the stem and the packing mounting section. Therefore, the packing can be easily attached to and detached from the stem holder, making replacement work easy.

[0015] Furthermore, in the valve device, the stem unit is oriented along the vertical direction, with the tip of the stem facing downwards and the opposite side facing upwards, and the direction perpendicular to the direction in which the stem extends is the horizontal direction. In this state, the packing mounting portion is formed with a constant vertical spacing, and when the packing is mounted on the stem holder, the width of the packing may be smaller than the vertical spacing of the packing mounting portion.

[0016] In this case, the valve device has a constant vertical spacing between the packing mounting portion in the stem unit, and the packing width is smaller than this vertical spacing. Therefore, the packing can be easily assembled without position adjustment when mounting it to the stem and stem holder. Since the packing is not subjected to pressure from the vertical direction, the generation of localized stress between the packing and the stem due to deformation caused by vertical pressure can be prevented. Therefore, the generation of localized sliding resistance between the packing and the stem is prevented, thereby increasing the durability of the packing.

[0017] Furthermore, the stem holder is connected to the upper end of the inclined guide surface and includes a stem holder shelf portion formed horizontally, and the first stem guide is provided with a first stem guide projection that protrudes horizontally. When the first stem guide is mounted on the stem holder, the lower surface of the first stem guide projection is placed on the stem holder shelf portion, and the lower end of the first stem guide faces the packing mounting portion. The vertical distance in the packing mounting portion may be a constant distance between the top surface of the packing mounting portion, which is fixed in a predetermined position by the lower end of the first stem guide, and the bottom surface formed at the upper end of the second stem guide.

[0018] In this case, the vertical spacing of the packing mounting portion is formed at a constant interval when the lower surface of the first stem guide protrusion is placed on the stem holder shelf. The packing width is smaller than this vertical spacing. Therefore, the packing can be easily assembled without position adjustment when attaching it to the stem and stem holder.

[0019] Furthermore, the valve device may have a packing that is formed in an annular shape and comprises an inner circumferential member and an outer circumferential member, wherein the coefficient of friction between the inner circumferential member and the stem is smaller than the coefficient of friction between the outer circumferential member and the inner circumferential portion of the packing mounting area, the outer circumferential member comprises an elastic member, the inner diameter of the packing is smaller than the outer diameter of the stem in the portion where the packing is inserted, and the outer diameter of the packing is larger than the inner diameter of the packing mounting area when mounted on the stem, the outer circumferential member elastically deforms in a direction along the horizontal direction when mounted on the packing mounting area, sealing the space between it and the inner circumferential portion of the packing mounting area, and the inner circumferential member seals the space between it and the stem by pressing against it in conjunction with the elastic deformation of the outer circumferential member.

[0020] In this case, the friction between the outer circumference member and the packing mounting area reduces vertical displacement, thereby enhancing the sealing effect. The coefficient of friction between the inner circumference member and the stem is smaller than that between the outer circumference member and the packing mounting area, so even when the stem moves vertically, it operates smoothly and maintains the sealing effect.

[0021] Furthermore, the valve device may have a packing width shorter than the maximum range of motion of the stem. In this case, since the packing width is shorter than the maximum range of motion of the stem, the vertical size of the valve device can be reduced. Thus, the valve device can be made smaller in the vertical direction.

[0022] Furthermore, the stem support length of the valve device, which is the sum of the lengths of the first stem guide, the packing, and the second stem guide that guide the stem, may be three times or more the maximum movable range of the stem. In this case, since the stem support length is three times or more the maximum movable range of the stem, the stem can operate more stably.

[0023] Furthermore, in the valve device, when the tip of the stem closes the internal flow path, the distance between the end of the stem holder on the tip side of the stem and the tip of the stem may be less than or equal to twice the stem support length.

[0024] In this case, the distance between the end of the stem chip on the side of the stem holder and the tip of the stem chip is not more than twice the stem support length, so the stem chip at the tip of the stem can open and close the internal flow path without wobbling.

Brief Description of the Drawings

[0025] [Figure 1] It is a diagram showing the whole valve device 1, showing the state where the stem chip 5 closes the internal flow path 23. [Figure 2] It is a diagram showing the whole valve device 1, showing the state where the stem chip 5 opens the internal flow path 23 and the fluid 20 flows from the inflow path 21 through the internal flow path 23 and out from the outflow path 22. [Figure 3] It is a cross-sectional view showing the main part of the valve device 1. [Figure 4] It is a diagram showing the configuration and mounting procedure of the first stem unit 3a. (a) shows the state before mounting each component, (b) shows the state after mounting each component, and (c) shows the first stem guide 8 in which the fixing means 9 is integrally formed. [Figure 5] It is a diagram showing the state of mounting the first stem unit 3a to the valve body 2. <00001 / 03>It is a diagram showing the procedure for disassembling the components from the state of the first stem unit 3a. (a) shows the state where the stem 4 is pulled downward from the first stem unit 3a, and (b) shows the state where the fixing member 9a (9), the stem 4 whose tip opens and closes the internal flow path 23, the first stem guide 8, and the packing 7 are further removed. [Figure 7] It is a cross-sectional view explaining the configuration of the packing 7. (a) is a diagram showing the state of the packing 7 alone, (b) is a diagram showing the state of being mounted on the stem, and (c) shows the lip packing 7c. <S [Figure 8] It is a detailed view of part A in FIG. 3. <S [Figure 9] It is a diagram showing the configuration and mounting procedure of the second stem unit 3b. (a) shows the state before mounting each component, and (b) shows the state after mounting each component. [Figure 10] This diagram shows the configuration and installation procedure of the third stem unit 3c, with (a) showing the state before each component is installed and (b) showing the state after each component has been installed. [Figure 11] This figure shows an evaluation machine that performed a comparative evaluation with the present invention, which is a conventional diaphragm valve device 40, where (a) shows the internal flow path 23 in a closed state and (b) shows the internal flow path 23 in an open state. [Figure 12] This figure shows an evaluation machine that performed a comparative evaluation with the present invention, which is a conventional bellows seal valve device 50. (a) shows the internal flow path 23 in a closed state, and (b) shows the internal flow path 23 in an open state. [Modes for carrying out the invention]

[0026] The valve device 1 embodying the present invention will be described below with reference to the drawings. The embodiments for carrying out the invention and the referenced drawings are used to illustrate the technical features that the present invention may adopt. The present invention is not limited to these. The configuration of the device shown in the drawings is not intended to be the sole limiting factor, but is merely an illustrative example.

[0027] <Overall configuration of valve device 1> The overall configuration of a valve device 1 according to an embodiment of the present invention will be described with reference to Figures 1 to 3. As shown in Figures 1 and 2, in the valve device 1, the stem 4 in the stem unit 3 is operated vertically by the action of an air cylinder 31, and the tip of the stem 4 opens and closes an internal flow path 23 between the inlet passage 21 and the outlet passage 22 of the fluid 20, thereby controlling the flow of the fluid 20. The valve device 1 comprises an inlet passage 21, an outlet passage 22, a valve body 2 in which the internal flow path 23 is formed, and a stem unit 3 that can be attached to or detached from the valve body 2.

[0028] Next, we will describe the individual components of the main part of the valve device 1. As shown in Figure 3, the positional relationship of each component will be described as the configuration when the bottom surface 2a of the valve body 2 is installed horizontally and the stem unit 3 is mounted vertically upward relative to the valve body 2.

[0029] <Configuration of the first stem unit 3a> In the following description, the stem unit 3 will be described using the first example, the first stem unit 3a, as an example. As shown in Figure 3, the first stem unit 3a comprises the following components. The first stem unit 3a is incorporated into a valve device 1 that controls the flow of fluid 20 by opening and closing an internal flow path 23 between the inlet passage 21 and the outlet passage 22 of the fluid 20. It comprises a stem 4 whose tip is for opening and closing the internal flow path 23. It comprises a stem holder 6 installed in the valve body 2 into which the stem 4 is inserted. It comprises a packing 7 inserted into the stem 4, having a predetermined packing width W1 in the direction in which the stem 4 extends, and mounted on the stem holder 6. The first stem unit 3a comprises a first stem guide 8 inserted into the stem 4 and mounted on the stem holder 6 with the packing 7 in between. The first stem unit 3a may be formed integrally with the first stem guide 8, or it may be formed separately and may include fixing means 9 for fixing the first stem guide 8 to the stem holder 6. Furthermore, the stem 4 may be equipped with a stem tip 5 at its tip, and the stem tip 5 may open and close by moving toward and away from an internal flow path 23 between the inlet passage 21 and the outlet passage 22 of the fluid 20, thereby controlling the flow of the fluid 20. The material of the stem tip 5 is mainly polyimide or fluororesin such as PCTFE, but other materials may also be used.

[0030] The first stem unit 3a has the following configuration when the tip of the stem 4 is facing downwards and the stem 4 is oriented vertically. The stem holder 6 is provided with a second stem guide 11, which is an opening hole that guides the stem 4 at its lower end. A packing mounting portion 12 is formed above the second stem guide 11. Furthermore, an inclined guide surface 13 is formed continuously above the packing mounting portion 12, and moves away from the stem 4 as it goes upwards. As shown in Figure 3, a part of the lower side of the first stem guide 8 may be inserted into the packing mounting portion 12, in which case the inner diameter of the packing mounting portion 12 is formed to correspond to the outer shape of the first stem guide 8.

[0031] As shown in Figure 4(b), the packing 7 is installed sandwiched between the first stem guide 8 and the second stem guide 11, and the stem 4 moves in the vertical direction guided by the first stem guide 8, the packing 7, and the second stem guide 11.

[0032] Furthermore, the following configuration may be included. As shown in Figure 8, the vertical spacing W2 of the packing mounting portion 12 is constant. The packing width W1 is formed to be smaller than the vertical spacing W2 of the packing mounting portion 12 when the first stem guide 8 is mounted on the stem holder 6.

[0033] <Effects of the overall configuration of valve device 1> As described above, the valve device 1 according to an embodiment of the present invention provides the following effects. As shown in Figure 3 and other figures, the valve device 1 operates with the stem 4 guided by the first stem guide 8, packing 7, and second stem guide 11 inside the stem holder 6. Therefore, it has a sealing effect that prevents fluid 20 from leaking and can operate stably. In addition, the packing 7 is guided by the inclined guide surface 13 when it is attached to the stem holder 6, so it can be easily attached. Furthermore, since the packing 7 is sandwiched between the first stem guide 8 and the stem holder 6 inside the stem holder 6, it is possible to prevent fragments of the packing 7 from spreading inside the valve device 1 when the packing 7 is damaged.

[0034] Furthermore, as shown in Figure 4, the valve device 1, with the configuration of the first stem unit 3a, which is an example of the stem unit 3, does not require adjustment when attaching the packing 7 to the stem holder 6. Since the stem holder 6 has an inclined guide surface 13, the packing 7 can be attached simply by inserting it into the packing mounting portion 12 while it is attached to the stem 4. Thus, the first stem unit 3a is easy to assemble, and the number of work steps required when assembling the packing 7 can be reduced.

[0035] As already explained, conventional methods use gland packing, which requires adjusting the tightening amount during assembly and parts replacement, posing a challenge to workability. In contrast, the valve device 1 of the present invention solves this problem and makes assembly easier.

[0036] As shown in Figure 8, in the first stem unit 3a, the packing width W1 may be formed smaller than the vertical distance W2 of the packing mounting portion 12 when the first stem guide 8 is mounted on the stem holder 6. In this case, the packing 7 is not subjected to pressure from the vertical direction, so the generation of local stress between the packing 7 and the stem 4 due to deformation caused by vertical pressure can be prevented. The sealing effect between the packing 7 and the stem 4 can be enhanced.

[0037] Furthermore, the first stem unit 3a is detachable from the valve body 2 as a unit. Therefore, the first stem unit 3a offers excellent ease of assembly and replaceability for the valve device 1. The second stem unit 3b and the third stem unit 3c, described later, also offer the same effect.

[0038] <Components attached to the main part of valve device 1> Next, referring to Figures 1 to 3, the components associated with the main part of the valve device 1 will be described. The valve device 1 includes an air cylinder 31 for operating the stem 4 and a valve holder 32 connected to the air cylinder 31 and detachable from the valve body 2.

[0039] The stem holder 6 has a flange portion 16 formed on its outer circumference approximately in the center in the vertical direction. When the first stem unit 3a is oriented vertically, the first stem unit 3a is installed with a gasket 17 in between the lower surface 16a of the flange 16 of the stem holder 6 and the valve body 2. The valve holder 32 is attached to the valve body 2 in contact with the upper surface 16b of the flange 16 of the stem holder 6.

[0040] As shown in Figure 3, the valve body 2 has male threads formed on a part of its outer circumference on the upper side in the vertical direction, and these are connected to the female threads formed on the valve holder 32 by screwing them together. In Figure 3, the valve holder 32 is shown by a dashed line and is composed of multiple members, but it may be formed as a single piece.

[0041] As explained above, the components attached to the main part of the valve device 1 have the following effects. The stem unit 3, such as the first stem unit 3a shown in Figures 3 and 5, is installed with a gasket 17 sandwiched between the lower surface 16a of the flange 16 of the stem holder 6 and the valve body 2, thereby preventing fluid 20 from leaking out from the gap between the stem holder 6 and the valve body 2.

[0042] <Configuration for installation and replacement of packing 7> Next, with reference to Figures 3, 4, 6, and 8, the configuration for attaching and replacing the packing 7 to the stem holder 6 will be described. The configuration for attaching the packing 7 to the packing mounting portion 12 will be described. The packing mounting portion 12 includes a packing shelf portion 12a formed at the boundary with the second stem guide 11 in a direction intersecting the direction in which the stem 4 is inserted. As shown in Figures 4(a) and 8, the inclined guide surface 13 guides the packing 7 when it is attached to the stem holder 6 with the packing 7 inserted into the stem 4, thereby enabling the packing 7 to be attached to the packing mounting portion 12.

[0043] The configuration for removing the packing 7 from the packing mounting portion 12 will now be described. As shown in Figure 6(a), the packing shelf portion 12a locks the packing 7 in place when the stem 4 is pulled out toward the tip end side of the stem 4 (the side of the stem tip 5) while the packing 7 is mounted on the packing mounting portion 12, making it possible to separate the packing 7 from the stem 4 and the packing mounting portion 12.

[0044] As shown in Figure 4(a), when the first stem guide 8 is formed separately from the fixing means 9, the first stem guide projection 8c may be cylindrical or polygonal prism-shaped. In either shape, the first stem guide projection 8c is formed so that it can be placed on the stem holder shelf 18. In the stem holder 6, the portion into which the first stem guide projection 8c is inserted is formed with a shape and dimensions that allow the first stem guide projection 8c to be inserted.

[0045] As described above, the inclined guide surface 13 provides the following effects. As shown in Figures 3, 4, and 8, the inclined guide surface 13 of the stem holder 6 guides the packing 7 when it is inserted into the stem 4 and mounted on the stem holder 6, so that the packing 7 can be easily mounted on the packing mounting section 12. Furthermore, as shown in Figure 6(a), when the stem 4 is removed from the state mounted on the packing mounting section 12 toward the tip side of the stem 4 (the side of the stem tip 5), the packing shelf 12a locks the packing 7 in place, making it possible to separate the packing 7 from the stem 4 and the packing mounting section 12.

[0046] Therefore, since the packing 7 can be easily attached to and detached from the stem holder 6, replacement work is easy. Because the packing 7, which is a consumable part, can be easily replaced in the valve device 1, maintenance costs associated with labor can be kept low. In addition, productivity can be increased by shortening the downtime of the valve device 1.

[0047] <Relationship between packing 7 and elements related to packing 7> Next, with reference to Figures 3, 4, and 8, the relationship between the packing 7 and the elements related to the packing 7 will be explained in detail. The following explanation assumes that the first stem unit 3a is oriented vertically, with the tip side of the stem 4 (the side with the stem tip 5) facing downwards and the opposite side facing upwards, and that the direction perpendicular to the direction in which the stem 4 extends is the horizontal direction.

[0048] As shown in Figure 8, the packing mounting portion 12 is formed with a constant vertical spacing W2 in the vertical direction. When the packing 7 is mounted on the stem holder 6, the packing width W1 is smaller than the vertical spacing W2 of the packing mounting portion 12.

[0049] As explained above, in the first stem unit 3a, the vertical spacing W2 of the packing mounting portion 12 is constant, and the packing width W1 is smaller than the vertical spacing W2. Therefore, the packing 7 can be easily assembled without position adjustment when mounting it to the stem 4 and stem holder 6. Since the packing 7 is not subjected to pressure from the vertical direction, the generation of local stress between the packing 7 and the stem 4 due to deformation caused by vertical pressure can be prevented. Therefore, the generation of local sliding resistance between the packing 7 and the stem 4 is prevented, and the durability of the packing 7 can be increased.

[0050] The configuration in which the first stem unit 3a forms the relationship between the packing width W1 and the vertical spacing W2 of the packing mounting portion 12 will be described below. The stem 4 has a cylindrical shape with a constant outer diameter in the portion that is guided and operated by at least the first stem guide 8, the packing 7, and the second stem guide 11. The stem holder 6 is connected to the upper end of the inclined guide surface 13 and includes a stem holder shelf portion 18 that is formed horizontally.

[0051] The vertical spacing W2 in the packing mounting portion 12 is formed to be constant by the following configuration. As shown in Figure 4, the first stem guide 8 has a first stem guide projection 8c that protrudes horizontally. When the first stem guide 8 is mounted on the stem holder 6, the lower surface 8b of the first stem guide projection 8c rests on the stem holder shelf portion 18, and the lower end portion 8a of the first stem guide 8 faces the packing mounting portion 12 (see Figure 4(b), etc.). The vertical spacing W2 in the packing mounting portion 12 is formed at a constant interval between the top surface portion of the packing mounting portion 12, which is fixed in a predetermined position by the lower end portion 8a of the first stem guide 8, and the bottom surface portion formed at the upper end of the second stem guide 11. The packing width W1 is formed to be smaller than the vertical spacing W2 of the packing mounting portion 12. The bottom surface of the packing mounting portion 12 is the packing shelf portion 12a, and the vertical distance W2 is the vertical distance between the lower end portion 8a of the first stem guide 8 and the packing shelf portion 12a.

[0052] The packing mounting portion 12 is a cylindrical recess formed in the stem holder 6. The inclined guide surface 13 is formed in a frustoconical shape so that it moves away from the stem 4 as it extends upward from the upper end of the cylindrical recess of the packing mounting portion 12. The upper end of the inclined guide surface 13 connects to the stem holder shelf portion 18. The first stem guide 8 has a cylindrical shape in the portion below the first stem guide protrusion 8c, and its outer diameter is formed in a clearance fit relationship with the inner diameter of the packing mounting portion 12. Note that the inner diameter dimension of the packing mounting portion 12 and the outer dimensions of the corresponding portion of the first stem guide 8 may be adjusted to suppress horizontal play.

[0053] Referring to Figure 4, the configuration of the fixing means 9 will be explained. Figure 4(a) shows the case where the fixing means 9 is configured separately from the first stem guide 8. The fixing means 9 has male threads formed on its outer circumference, and the stem holder 6 has female threads formed on the inner circumference of the part to which the fixing means 9 is attached. Figure 4(c) shows the case where the fixing means 9 is formed integrally with the first stem guide 8. In this case, male threads are formed on a part of the outer circumference of the first stem guide 8. The stem holder 6 has female threads formed in the same way as in Figure 4(a). The assembly procedure for the first stem unit 3a will be described later. Note that, as will be described later, the fixing means 9 is not necessarily required.

[0054] As described above, the relationship between the packing width W1 and the vertical spacing W2 of the packing mounting portion 12 provides the following effects for the valve device 1. As shown in Figures 3 and 4, when the first stem guide 8 is mounted on the stem holder 6 with the first stem guide protrusion 8c formed, the lower surface 8b of the first stem guide protrusion 8c rests on the stem holder shelf portion 18. The lower end 8a of the first stem guide 8 faces the packing mounting portion 12, and the lower end 8a of the first stem guide 8 forms the top surface of the packing mounting portion 12. Therefore, the vertical spacing W2 of the packing mounting portion 12 is formed at a constant interval between the lower end 8a of the first stem guide 8 and the packing shelf portion 12a when the first stem guide 8 is mounted on the stem holder 6. The packing width W1 is smaller than the vertical spacing W2. Therefore, the packing 7 can be easily assembled without position adjustment when mounted on the stem 4 and stem holder 6. The valve device 1 can reduce the assembly time of the packing 7.

[0055] Furthermore, when the first stem guide 8 is mounted on the stem holder 6, the packing width W1 of the packing 7 is formed to be smaller than the vertical distance W2 of the packing mounting portion 12. Since the packing 7 is not subjected to pressure from the vertical direction, the generation of localized stress between the packing 7 and the stem 4 due to deformation caused by vertical pressure can be prevented. Therefore, the generation of localized sliding resistance between the packing 7 and the stem 4 is prevented, thereby increasing the durability of the packing 7. At the same time, the sealing effect between the packing 7 and the stem 4 can be improved.

[0056] Next, with reference to Figures 7(a), (b), and 8, the packing 7 and its relationship to related components will be described in detail. The packing 7 is formed in an annular shape and comprises an inner circumferential member 7a and an outer circumferential member 7b. The coefficient of friction between the inner circumferential member 7a and the stem 4 is smaller than the coefficient of friction between the outer circumferential member 7b and the inner circumferential portion 12b of the packing mounting part. The outer circumferential member 7b comprises an elastic member. For example, the inner circumferential member 7a is formed in an annular shape from a sheet-like member containing fluororesin, and the elastic member of the outer circumferential member 7b is formed in a ring shape containing nitrile rubber or fluororubber. The inner circumferential member 7a and the outer circumferential member 7b are formed separately and are combined by fitting the outer circumferential member 7b into the inner circumferential member 7a.

[0057] The inner diameter D3 of the packing is smaller than the outer diameter D1 of the stem in the portion where the packing 7 is inserted. The outer diameter D4 of the packing is larger than the inner diameter D2 of the packing mounting portion when it is mounted on the stem 4. When the outer peripheral member 7b is mounted on the packing mounting portion 12, it elastically deforms in a direction along the horizontal direction, sealing the space between it and the inner peripheral portion 12b of the packing mounting portion.

[0058] The inner circumferential member 7a seals the space between itself and the stem 4 by pressing against the stem 4 as the outer circumferential member 7b undergoes elastic deformation. Furthermore, when the first stem guide 8 is mounted on the stem holder 6, a gap is formed in the vertical direction at the packing mounting portion 12 of the packing 7.

[0059] Next, with reference to Figure 7(c), another example of packing 7, the lip packing 7c, will be described. When the lip packing 7c is mounted on the stem 4, a U-shaped groove 7e is formed in the lower tip portion 7d. The lip packing 7c is formed as a single unit, and in its standalone state, the groove 7e in the tip portion 7d is in a V-shape. When mounted on the stem 4 and inserted into the stem holder 6, the elastic force generated when the tip portion 7d deforms inward causes the lip packing 7c to adhere tightly to the stem 4 and the stem holder 6.

[0060] The packing 7 and related components described above provide the following effects. As shown in Figures 7 and 8, the outer peripheral member 7b is formed of an elastic material, so even if there are variations in the outer dimensions of the packing 7, it can elastically deform to fill the gap between it and the inner peripheral portion 12b of the packing mounting portion. In the operating state of the valve device 1, pressure is generated in the inlet passage 21 and outlet passage 22 inside the valve body 2 by the fluid 20. The packing 7 is pushed up toward the surface of the lower end portion 8a of the first stem guide 8 by the internal pressure of the valve body 2. Therefore, the packing 7 is compressed in the vertical direction and deforms to stretch in the outer and inner diameter directions, thereby enhancing the sealing effect between it and the second stem guide 11.

[0061] Furthermore, the inner circumferential member 7a applies pressure to the stem 4 as the outer circumferential member 7b elastically deforms, so no gap is created between the packing 7 and the stem 4. The coefficient of friction between the inner circumferential member 7a and the stem 4 is smaller than that between the outer circumferential member 7b and the packing mounting portion 12, so even when the stem 4 moves in the vertical direction, it operates smoothly and maintains its sealing effect.

[0062] Furthermore, the lip packing 7c adheres tightly to the stem 4 and stem holder 6 due to the elastic deformation of its tip portion 7d, allowing it to operate smoothly and maintain its sealing effect even when the stem 4 moves in the vertical direction. In operation, the lip packing 7c deforms in a direction that expands (the inner diameter side towards the stem 4 and the outer diameter side towards the stem holder 6) due to the fluid pressure acting from below, thereby enhancing the sealing effect.

[0063] <Relationship between the maximum range of motion L2 of stem 4 and the packing width W1 of packing 7> Next, the relationship between the maximum range of motion L2 of the stem 4 and the packing width W1 of the packing 7 will be explained. The packing width W1 of the packing 7 is shorter than the maximum range of motion L2 of the stem 4. As shown in Figure 3, the maximum range of motion of the stem 4 is between the end 6a on the stem tip 5 side of the stem holder 6 and the upper end of the stepped portion 4a of the stem 4, when the stem tip (stem tip 5) is closing the internal flow path 23, and this is the maximum range of motion L2. The packing width W1 is formed to be shorter than the maximum range of motion L2.

[0064] The relationship between the maximum range of motion L2 of the stem 4 and the packing width W1 of the packing 7, as explained above, produces the following effects. As shown in Figures 3 and 8, since the packing width W1 is shorter than the maximum range of motion L2 of the stem 4, the vertical size of the valve device 1 can be reduced. If the packing width W1 were longer, the stem 4 would need to be longer, leading to an increase in the size of the valve device 1 in the vertical direction. In contrast, the valve device 1 can be made smaller in the vertical direction.

[0065] <Relationship between stem support length L1 and maximum range of motion L2 of stem 4> Next, with reference to Figure 3, the relationship between the stem support length L1 and the maximum range of motion L2 of the stem 4 will be explained. The stem support length L1 is the sum of the lengths over which the first stem guide 8, packing 7, and second stem guide 11 guide the stem 4. The stem support length L1 is at least three times the maximum range of motion L2 of the stem 4. The stem support length L1 only needs to be the sum of the lengths over which the first stem guide 8, packing 7, and second stem guide 11 guide the stem 4, and the lengths of each of the first stem guide 8, packing 7, and second stem guide 11 can be varied. In the example shown in Figure 3, the length over which the first stem guide 8 guides the stem 4 is the longest, but this is not limited to this, and for example, the length over which the second stem guide 11 guides the stem 4 may be the longest.

[0066] The relationship between the stem support length L1 and the maximum range of motion L2 of the stem 4 serves as an indicator of whether the stem 4 operates stably or not. The longer the stem support length L1 is relative to the range of motion of the stem 4, the more stably the stem 4 operates.

[0067] The relationship between the stem support length L1 and the maximum range of motion L2 of the stem 4, as described above, produces the following effects. As shown in Figure 3, the valve device 1 has a stem support length L1 that is at least three times the maximum range of motion L2 of the stem 4. Conventionally, the length of L1 was generally about twice that of L2. The longer the length of L1 is compared to the length of L2, the more stably the stem 4 operates, so it is preferable for L1 to be longer than L2. Therefore, the stem 4 can operate more stably.

[0068] <Relationship between stem support length L1 and distance L3> Next, referring to Figure 3, the relationship between the stem support length L1 and the distance L3 between the end 6a of the stem holder 6 on the tip side of the stem 4 (the side of the stem tip 5) and the tip of the stem 4 (the tip of the stem tip 5) will be explained. When the tip of the stem 4 (the stem tip 5) closes the internal flow path 23, the distance L3 between the end 6a of the stem holder 6 on the tip side of the stem 4 and the tip of the stem 4 is less than or equal to twice the stem support length L1.

[0069] Distance L3 indicates the length of the member over which the stem 4 forms a so-called cantilever structure. The shorter distance L3 is relative to the stem support length L1, the more stable the structure becomes. Conventionally, distance L3 was generally more than twice the length of L1. The smaller the length of distance L3 is compared to L1, the shorter the length over which the stem 4 forms a so-called cantilever structure.

[0070] The relationship between the stem support length L1 and the distance L3 described above produces the following effects. The longer the cantilevered length of the stem 4, the more prone the tip (stem tip 5) is to wobble. As a result, the position where the tip presses down and the position of the internal flow path 23 become misaligned, causing fluid 20 to leak. It is preferable for the cantilevered length L3 of the stem 4 to be shorter. In the configuration of the valve device 1, the cantilevered length L3 of the stem 4 is formed to be shorter than the stem support length L1, so the wobble of the tip (stem tip 5) is reduced, and the internal flow path 23 can be opened and closed more reliably.

[0071] <Configuration of the second stem unit 3b> Next, other examples of the stem unit 3 will be described. The stem unit 3 may also have the following configuration. Elements with the same function as the first stem unit 3a are denoted by the same reference numerals and their descriptions may be omitted. Figure 9 shows the second stem unit 3b, which is a second example of the stem unit 3. The second stem unit 3b is the same as the first stem unit 3a except for the following configuration. As shown in Figure 4, the first stem unit 3a has an inclined guide surface 13 formed continuously above the packing mounting portion 12 in the stem holder 6, which moves away from the stem 4 as it goes upwards. In contrast, as shown in Figure 9, the second stem unit 3b does not have an inclined guide surface 13 formed in the stem holder 26, and has a continuous cylindrical shape from the packing shelf portion 12a to the stem holder shelf portion 18.

[0072] Furthermore, as shown in Figure 4, the first stem unit 3a is equipped with a stem tip 5 at the tip of the stem 4. In contrast, as shown in Figure 9, the second stem unit 3b is configured such that the tip 24b of the stem 24 directly contacts and separates from the internal flow path 23. The upper end of the stepped portion 24a restricts the upward movement of the stem 4, similar to the upper end of the stepped portion 4a of the first stem unit 3a. In other words, when the stem 4 moves upward, the upper end of the stepped portion 24a contacts the lower end of the stem holder 6, thereby restricting its movement. Moreover, the first stem unit 3a is equipped with a fixing means 9, but the second stem unit 3b does not have a separate fixing means because the first stem guide 8 also serves as the fixing means. As shown in Figure 9, the first stem guide 8 is fixed by a press-fit relationship between the first stem guide protrusion 8c and the protrusion 19 of the stem holder 26. Note that the first stem guide 8 does not necessarily have to also serve as the fixing means. For example, although not shown in the diagram, the valve holder 32 may include a member that holds the first stem guide 8 in place, preventing the first stem guide 8 from moving upward.

[0073] As shown in Figure 9, the configuration of the second stem unit 3b is as follows, including the configuration common to the first stem unit 3a. The second stem unit 3b is incorporated into a valve device 1 that controls the flow of fluid 20 by opening and closing an internal flow path 23 between the inlet passage 21 and the outlet passage 22 of the fluid 20. It comprises a stem 24 whose tip opens and closes the internal flow path 23, and a stem holder 26 installed in the valve body 2 into which the stem 24 is inserted. The second stem unit 3b comprises a packing 7 inserted into the stem 24, having a predetermined packing width W1 in the direction in which the stem 24 extends, and mounted on the stem holder 26. Furthermore, it comprises a first stem guide 8 inserted into the stem 24 and mounted on the stem holder 26 with the packing 7 in between.

[0074] When the tip portion 24b is facing downwards and the stem 24 is oriented vertically, the stem holder 26 includes a second stem guide 11, which is an opening at the lower end for guiding the stem 24, and a packing mounting portion 12 formed above the second stem guide 11. The packing 7 is mounted sandwiched between the second stem guide 11 and the first stem guide 8, and the vertical spacing W2 of the packing mounting portion 12 is constant. When the first stem guide 8 is mounted on the stem holder 26, the packing width W1 of the packing 7 is formed to be smaller than the vertical spacing W2 of the packing mounting portion 12.

[0075] The configuration of the second stem unit 3b described above provides the following effects. As shown in Figure 9, the second stem unit 3b has a constant vertical spacing W2 of the packing mounting portion 12, and the packing width W1 is smaller than the vertical spacing W2. Therefore, the packing 7 can be easily assembled without position adjustment when mounted on the stem 4 and stem holder 26. Since the packing 7 is not subjected to pressure from the vertical direction, the generation of localized stress between the packing 7 and the stem 4 due to deformation caused by vertical pressure can be prevented. Therefore, the generation of localized sliding resistance between the packing 7 and the stem 4 is prevented, thereby increasing the durability of the packing 7. Furthermore, similar to the first stem unit 3a, it is detachable as a unit from the valve body 2. Therefore, the second stem unit 3b provides excellent ease of assembly and replaceability for the valve device 1.

[0076] <Configuration of the third stem unit 3c> Furthermore, the stem unit 3 may have the following configuration. Figure 10 shows a third example of the stem unit 3, the third stem unit 3c. The third stem unit 3c is the same as the first stem unit 3a except for the following configuration. As shown in Figure 4, in the first stem unit 3a, the lower surface 8b of the first stem guide protrusion 8c is placed on the stem holder shelf 18. The packing mounting portion 12 has a constant vertical spacing W2 because the top surface of the packing mounting portion 12 is formed by the lower end portion 8a of the first stem guide 8. The packing width W1 is formed to be smaller than the vertical spacing W2 of the packing mounting portion 12.

[0077] In contrast, as shown in Figure 10, the third stem unit 3c does not have a stem holder shelf portion 18 formed on the stem holder 36. As shown in Figure 10(a), the packing 7 is pressed down by the first stem guide 8 and mounted on the stem 4, but the vertical spacing W2 of the packing mounting portion 12 is determined by the position of the lower end portion 8a when the first stem guide 8 presses down. When the first stem guide 8 is pressed down without any gap between the lower end portion 8a and the packing 7, and the lower end portion of the packing 7 is in contact with the packing shelf portion 12a, the vertical spacing W2 is the same as the packing width W1. That is, the vertical spacing W2 is formed by pressing the first stem guide 8 toward the packing shelf portion 12a in accordance with the packing width W1.

[0078] As shown in Figure 10, the configuration of the third stem unit 3c is as follows, including the configuration common to the first stem unit 3a. The third stem unit 3c is incorporated into a valve device 1 that controls the flow of fluid 20 by opening and closing an internal flow path 23 between the inlet passage 21 and the outlet passage 22 of the fluid 20. It comprises a stem 4 whose tip opens and closes the internal flow path 23, and a stem holder 36 installed in the valve body 2 into which the stem 4 is inserted. It comprises a packing 7 inserted into the stem 4 and having a predetermined packing width W1 in the direction in which the stem 4 extends, and which is mounted on the stem holder 36, and a first stem guide 8 inserted into the stem 4 and mounted on the stem holder 36 with the packing 7 in between.

[0079] When the tip is facing downwards and the stem 4 is oriented vertically, the stem holder 36 includes a second stem guide 11, which is an opening at the lower end for guiding the stem 4, and a packing mounting portion 12 formed above the second stem guide 11. The stem holder 36 is formed continuously above the packing mounting portion 12 and has an inclined guide surface 13 that moves away from the stem 4 as it goes upwards. The packing 7 is mounted sandwiched between the second stem guide 11 and the first stem guide 8.

[0080] The configuration of the third stem unit 3c described above provides the following effects. As shown in Figure 10, the third stem unit 3c can be easily installed because the packing 7 is guided by the inclined guide surface 13 when it is installed on the stem holder 36. Furthermore, similar to the first stem unit 3a, it is detachable as a unit from the valve body 2. Therefore, the third stem unit 3c provides excellent ease of assembly and replaceability for the valve device 1.

[0081] <Assembly procedure for valve device 1> Next, referring to Figures 4 to 6, the assembly and disassembly procedures for the main parts of the valve device 1 will be explained. As shown in Figure 4(a), the case of assembling the stem unit 3 in the vertical direction will be explained. The first stem unit 3a will be used as an example for the stem unit 3. The stem tip 5 is inserted and press-fitted from the bottom of the stem 4. The stem tip 5 can be replaced when necessary depending on the usage conditions.

[0082] Next, insert the stem 4 into the stem holder 6 from the bottom. Insert the packing 7 from the top with the stem 4 inserted into the stem holder 6. As shown in Figure 8, it is not necessary to insert the packing 7 all the way to the packing mounting portion 12 of the stem holder 6 at this point. Insert the first stem guide 8 onto the stem 4 from above the packing 7. At this time, push the first stem guide 8 downwards until the packing 7 reaches the packing mounting portion 12.

[0083] The fixing member 9a, which serves as the fixing means 9, is inserted into the stem 4 from the upper side of the first stem guide 8, and its male threaded portion is screwed into the female threaded portion of the stem holder 6. The inner diameter of the fixing member 9a has a hexagonal hole that passes through it in the vertical direction, allowing it to be tightened to the stem holder 6 using a hex wrench. A spanner hook is provided on the lower outer diameter of the stem holder 6. At this time, the fixing member 9a is moved downward until the lower surface 8b of the protrusion 8c of the first stem guide contacts the stem holder shelf 18, resulting in the state of the first stem unit 3a shown in Figure 4(b). If the first stem guide 8 is integrated with the fixing means 9 (see Figure 4(c)), the installation of the first stem guide 8 and its fixing to the stem holder 6 are performed simultaneously.

[0084] Next, as shown in Figure 5, the first stem unit 3a is attached to the valve body 2. The male threaded portion at the upper end of the stem 4 is screwed onto the rod (female threaded portion) of the air cylinder 31, and the first stem unit 3a is attached to the air cylinder 31. The lower surface 16a of the flange portion 16 of the stem holder 6 on the first stem unit 3a is mounted on the upper end surface of the valve body 2 via the gasket 17. The horizontal position of the stem unit 3 is determined by the outer circumference of the stepped portion 6b of the stem holder 6 and the inner circumference 2b of the valve body 2. Furthermore, as shown in Figure 3, the valve holder 32 is screwed onto the valve body 2 and attached.

[0085] As shown in Figure 4, a wrench hook 15 with a hexagonal outer shape in plan view is formed on the lower side of the stepped portion 4a of the stem 4. The wrench hook 15 is used when screwing the male threaded portion formed at the upper end of the stem 4 into the air cylinder 31, as shown in Figure 3. In the second stem unit 3b, which will be described later, a wrench hook 15 is also formed on the stem 24, as shown in Figure 9.

[0086] Next, the procedure for replacing the packing 7 will be explained. As shown in Figure 6(a), the stem 4 is removed downwards from the stem holder 6. At this time, the packing 7 is held inside the stem holder 6 by the packing shelf 12a. The first stem guide 8 is also held inside the stem holder 6 by the stem holder shelf 18. The fixing member 9a is removed upwards from the stem holder 6 while rotating it in the opposite direction to how it was assembled.

[0087] Next, the first stem guide 8 and the packing 7 are removed from the stem holder 6 in order. As shown in Figure 6(b), the outer circumference member 7b of the packing 7 may be elastically deformed relative to the packing mounting portion 12, but when detached from the stem 4, the inner diameter of the inner circumference member 7a is smaller. The packing 7 can be easily removed by inserting a jig J corresponding to the shaft diameter of the stem 4 from the bottom of the stem holder 6. Note that it is not always necessary to use the jig J when removing the packing 7. If the outer circumference member 7b of the packing 7 is not elastically deformed, it can be easily removed without using the jig J. Alternatively, it can be pushed out with a flathead screwdriver or the like without using the jig J.

[0088] Next, we will explain the case where the stem unit 3 is the second stem unit 3b as an example. The differences from the first stem unit 3a are as follows: In the second stem unit 3b, the tip portion 24b is directly inserted into the internal flow path 23, so there is no need to insert the stem tip 5 into the stem 24. Also, instead of having a fixing member 9a, the second stem unit 3b is fixed in a press-fit state when the first stem guide 8 is inserted into the stem holder 26.

[0089] Next, we will explain the case where the stem unit 3 is the third stem unit 3c as an example. The differences from the first stem unit 3a are as follows. As shown in Figure 10, the stem holder 36 of the third stem unit 3c does not have a stem holder shelf portion 18 formed thereon. As shown in Figure 10(a), the packing 7 is pressed down by the first stem guide 8 and mounted on the stem 4, but the vertical spacing W2 of the packing mounting portion 12 is determined by the position of the lower end portion 8a when the first stem guide 8 presses down. When the first stem guide 8 is pressed down without any gap between the lower end portion 8a and the packing 7, and the lower end portion of the packing 7 is in contact with the packing shelf portion 12a, the vertical spacing W2 is the same as the packing width W1. That is, the vertical spacing W2 is formed by pressing the first stem guide 8 toward the packing shelf portion 12a according to the packing width W1.

[0090] As explained above, the packing 7 can be easily assembled and replaced in the stem unit 3. The packing 7 is a consumable part that is frequently replaced in order to extend the lifespan of the valve device 1. With the configuration of the valve device 1, assembly and replacement of the packing 7 do not require any adjustment, and the amount of work required can be reduced compared to conventional methods.

[0091] <Explanation regarding the durability of valve device 1> Next, the durability of the valve device 1 will be described in comparison with the conventional technology. As shown in Figure 11, conventionally, there was a diaphragm-type valve device 40 as the first device. The diaphragm-type valve device 40 comprises a valve body 42 having an inlet passage 21 and an outlet passage 22, a diaphragm 43 that allows or blocks the flow of fluid 20 in the internal flow path 23 from the inlet passage 21 to the outlet passage 22 of the valve body 42, and an actuator (not shown) that actsuates a plunger 44 directly connected to the diaphragm 43.

[0092] Furthermore, as shown in Figure 12, conventionally, there was a bellows seal valve device 50 as a second device. The stem 54 of the bellows seal valve device 50 is sealed by a bellows 53. The stem 54 is actuated by an actuator (not shown), so that the stem tip 55 at the end of the stem 54 allows or blocks the flow of fluid 20 in the internal flow path 23 from the inlet passage 21 to the outlet passage 22 of the valve body 52. ​​The relationship between the stem 54 and the stem tip 55 is the same as that of the valve device 1 of the present invention.

[0093] To compare the valve device 1 of the present invention with a conventional device, the valve bodies 2 shown in Figures 3 and 4 were reused and designated as valve body 42 and valve body 52, respectively. As shown in Figures 11 and 12, the conventional first device, a diaphragm-type valve device 40, and the second device, a bellows-seal valve device 50, were evaluated by replacing the part corresponding to the stem unit 3 with the present invention's valve body 42 and valve body 52, respectively. Shut-off valves (not shown) were installed in the inlet passage 21 and the outlet passage 22, respectively.

[0094] The evaluation was carried out using the following procedure. First, polyol, the raw material for urethane foam, was filled into the valve device with the internal passage 23 open. Once the air in the valve device was removed, the shut-off valve on the outlet passage 22 side was closed, and then the shut-off valve on the inlet passage 21 side was closed. The filling pressure inside the valve device was adjusted to 9-10 MPa to block the internal passage 23. That is, in the case of the diaphragm type valve device 40, the diaphragm 43 was closed (see Figure 11(a)), and in the case of the bellows seal valve device 50 and the valve device 1 of the present invention, the stem tip 55(5) was closed to block the internal passage 23 (see Figure 12(a)).

[0095] Next, the internal passage 23 is opened and closed continuously in each valve device. The opening and closing times are 1 second each for the open and closed states. This is repeated 30 times per minute. In the case of the diaphragm valve device 40, as shown in Figure 11(b), the diaphragm 43 deforms upward as the pressure from the plunger 44 is released, opening the internal passage 23. In the case of the bellows seal valve device 50, as shown in Figure 12(b), the stem 54 moves upward and the stem tip 55 opens, similar to valve device 1.

[0096] To monitor for fluid leakage 20 within the valve device and damage to each diaphragm 43, bellows 53, and packing 7, the following indicators were used. The first indicator was monitoring the pressure within the valve device; an abnormality was determined when the pressure fell below 9 MPa. The second indicator was measuring the pressure on the inlet side 21 and the pressure on the outlet side 22; an abnormality was determined based on whether the pressure difference was 1 MPa or less. The third indicator was monitoring the temperature of the liquid (polyol) in the flow path within the valve device.

[0097] The test results were as follows: In the first device, a diaphragm-type valve device 40, the diaphragm 43 broke and liquid leakage occurred after 650,000 cycles of opening and closing operations on the internal flow path 23. In the second device, a bellows-seal valve device 50, the bellows 53 broke and liquid leakage occurred after 39,000 to 84,000 cycles of opening and closing operations on the internal flow path 23. In contrast, no abnormalities were detected in the valve device 1 of the present invention even after 1,300,000 cycles of opening and closing operations on the internal flow path 23.

[0098] Based on the above, the valve device 1 of the present invention demonstrated superior durability compared to conventional diaphragm-type valve devices 40 and bellows-seal valve devices 50. Therefore, the valve device 1 of the present invention can be said to be a more reliable device compared to conventional devices.

[0099] Furthermore, the diaphragm valve device 40 experienced the following problems due to the damage to the diaphragm 43. Because the device was used continuously with the diaphragm 43 damaged, fragments of the diaphragm 43 struck the inside of the valve device, causing chipping and roughening of the surface. In this case, the conventional diaphragm valve device 40 required not only replacement of the diaphragm 43 but also repair or replacement of the internal components of the valve device.

[0100] In contrast, the valve device 1 of the present invention solves this problem as well. Since the packing 7 is installed sandwiched between the first stem guide 8 and the second stem guide 11, even if the packing 7 is damaged, it is prevented from fragments scattering inside the valve device 1, preventing damage from impacts to the inside or roughening of the surface. [Explanation of Symbols]

[0101] 1. Valve device 2 Valve Body 2a Bottom 2b Inner circumference 3 Stem Unit 4 Stems 5 Stem Tips 6 Stem holder 6a end 7. Packing 7a Inner circumference side member 7b Outer peripheral member 7d Tip 8. First stem guide 8a Lower end 8b Bottom side 8c First stem guide protrusion 9 Fixing means 11. Second Stem Guide 12. Packing mounting section 12a Packing shelf section 12b Inner circumference of the packing mounting area 13 Inclined guideway 16. Guard section 16a Lower side 16b Top side 17 Gasket 18 Stem holder shelf section 20 fluid 21 Inflow channel 22 Outflow channel 23 Internal flow path 24 Stem 24b Tip 26 Stem Holder 31 Air Cylinder 32 Valve holder 36 Stem Holder 42 Valve Body D1 Stem outer diameter D2 Inner diameter of packing mounting area D3 Packing inner diameter D4 Packing outer diameter L2 maximum movement amount L3 Distance W1 Packing width W2 Vertical spacing

Claims

1. A valve device that controls the flow of a fluid by opening and closing an internal flow path between a fluid inlet passage and an outlet passage, The inlet passage, the outlet passage, and the valve body in which the internal flow path is formed, The valve body is equipped with a stem unit that can be attached to or removed from it. The aforementioned stem unit is The tip has a stem for opening and closing the internal flow path, A stem holder is installed on the valve body into which the stem is inserted, Equipped with a gasket, The aforementioned stem holder is equipped with a packing mounting portion, The aforementioned packing is A valve device formed in an annular shape, having a predetermined packing width in the direction in which the stem extends, mounted on the stem holder with the stem inserted, and satisfying at least one of the following (1) to (3). (1) The stem unit is equipped with a first stem guide, The first stem guide is attached to the stem holder with the packing in between when the stem is inserted. The stem holder comprises a second stem guide, which is an opening at the lower end for guiding the stem, and a packing mounting portion formed above the second stem guide. The packing is installed sandwiched between the first stem guide and the second stem guide. The stem operates guided by the first stem guide, the packing, and the second stem guide. (2) The stem unit is oriented in a direction along the vertical direction, with the tip of the stem facing downwards and the opposite side facing upwards, and the direction perpendicular to the direction in which the stem extends is the horizontal direction, An inclined guide surface is formed continuously above the packing mounting portion, and moves away from the stem as it extends upward. (3) The packing mounting portion is formed at regular intervals in the direction in which the stem extends, The width of the packing is smaller than the spacing of the packing mounting portion.

2. A stem unit that can be attached to and detached from a valve device that controls the flow of fluid by opening and closing an internal flow path between a fluid inlet passage and an outlet passage, The tip has a stem for opening and closing the internal flow path, A stem holder into which the aforementioned stem is inserted, Gasket and, Equipped with a first stem guide, The aforementioned stem holder is A second stem guide, which is an opening hole at the lower end for guiding the stem, The second stem guide is equipped with a packing mounting portion formed on the upper side, The aforementioned packing is It is formed in an annular shape, has a predetermined packing width in the direction in which the stem extends, and is mounted in the stem holder with the stem inserted. The first stem guide is attached to the stem holder with the packing in between when the stem is inserted. The packing is installed sandwiched between the first stem guide and the second stem guide. The stem is connected to the first stem guide, the packing, and the second stem guide. A stem unit that operates from within.

Images