Ball valve

Abstract

The present invention provides a ball valve with a simple structure that can accommodate an orifice flow path that enables flow rate switching. [Solution] The ball valve 1 comprises a casing 3 with a valve chamber 9 in the middle of the flow path, a valve body 20 with a through hole 21 formed therein, and a valve stem 30 that rotatably supports the valve body within the valve chamber. By rotating the valve body, the valve valve 1 switches between a fully open state in which the inlet side and outlet side communicate through the through hole, and an orifice discharge state in which the outlet side is closed by the surface 20a of the valve body. The casing has a support hole 5b that leads from the valve chamber 9 to the outside of the casing into which the valve stem is inserted. The valve body has a branch hole 23 that branches off from the through hole and opens on the surface of the valve body so that the inlet side and the through hole communicate in the orifice discharge state. The valve stem has an orifice flow path 35 that communicates with the through hole and extends axially inside the valve stem to communicate with the outside of the casing.

Description

Technical Field

[0001] The technology of the present disclosure relates to a ball valve.

Background Art

[0002] Conventionally, by rotating a spherical valve body housed in a valve chamber provided in the middle of a flow path in a casing so as to block the flow path, the inflow side and the outflow side of the flow path are blocked, and through a through hole formed in the valve body, the inflow side and the outflow side of the flow path are communicated. A ball valve that switches between the two states is known. Such a ball valve is widely used from household to industrial applications because of its simple structure and high operability that allows opening and closing only by rotating the valve body.

[0003] By the way, in such a ball valve, separate from a flow path (temporarily referred to as "main flow path") that allows fluid to flow from the inflow side to the outflow side through a through hole formed in the valve body, for example, if the fluid is air, water, warm water, etc., a smaller flow rate than the main flow path is possible, and for example, if the fluid is steam, there is a desire to provide an orifice flow path for flow rate switching that mainly enables drainage.

[0004] In this regard, for example, in Patent Document 1, when the ball valve is rotated by a predetermined angle, the secondary side water passage is closed and the primary side water passage is in a semi-open state. The primary side opening diameter of the ball valve water passage hole is made larger and the secondary side opening diameter is made smaller. A backflow prevention water stop valve is disclosed that sets a bypass flow path (orifice flow path) in which the secondary side opening that is disengaged from the secondary side water passage communicates with the secondary side rear when the ball valve is rotated by a predetermined angle.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] If an orifice passage that enables flow rate switching is to be provided in a ball valve, as in the case of Patent Document 1 mentioned above, the diameter of the ball valve water passage hole may have to be made different on the primary and secondary sides, or the valve chamber may become complex in order to set up a bypass passage, which may undermine the advantage of the ball valve, which is its simple structure.

[0007] The technology disclosed herein has been made in view of the above, and its purpose is to provide a ball valve with an orifice flow path that enables flow rate switching with a simple structure. [Means for solving the problem]

[0008] The ball valve of the present disclosure comprises a casing having a fluid passage through which a fluid flows, with a valve chamber provided in the middle of the passage; a spherical valve body having a through hole housed in the valve chamber; and a valve shaft that rotatably supports the valve body relative to the casing, wherein the ball valve switches between a first state in which the inlet and outlet sides of the passage are in communication through the through hole, and a second state in which the outlet side of the passage is closed by a surface of the valve body where the hole is not open, wherein the casing has a support hole formed therein that extends from the valve chamber to the outside of the casing into which the valve shaft is inserted; the valve body has a branch hole formed therein that branches from the through hole and opens on the surface of the valve body so that the inlet side of the passage and the through hole are in communication in the second state; and the valve shaft has an orifice passage formed therein that communicates with the through hole and extends axially within the valve shaft to communicate with the outside of the casing, and has an orifice passage smaller in diameter than the through hole. [Effects of the Invention]

[0009] According to the ball valve of this disclosure, an orifice flow path that enables flow rate switching can be provided with a simple structure. [Brief explanation of the drawing]

[0010] [Figure 1] This figure schematically shows the external appearance of the ball valve according to Embodiment 1. [Figure 2] This is a schematic cross-sectional view of a ball valve. [Figure 3] This is a schematic cross-sectional view showing a ball valve in a state where the valve body has been rotated from the state shown in Figure 2. [Figure 4] This is a cross-sectional view taken along the line IV-IV in Figure 2. [Figure 5] This is a cross-sectional view taken along the VV line in Figure 3. [Figure 6] This is a cross-sectional view of the valve body after it has been rotated 180° from the state shown in Figure 5. [Figure 7] This diagram schematically shows the steam flow inside the ball valve when it is fully open. [Figure 8] This is a cross-sectional view taken along the line VIII-VIII in Figure 7. [Figure 9] This diagram schematically shows the flow of steam and condensate inside the ball valve when it is fully open. [Figure 10] This diagram schematically shows the flow of drain water inside a ball valve when the orifice is discharged. [Figure 11] This diagram schematically illustrates the procedure for changing the diameter of the orifice channel. [Figure 12] This figure schematically shows a valve stem according to a modified example of Embodiment 1. [Figure 13] This is a schematic cross-sectional view showing a ball valve according to Embodiment 2. [Figure 14] This figure schematically shows a ball valve according to another embodiment. [Figure 15] This figure schematically shows a valve body according to another embodiment. [Modes for carrying out the invention]

[0011] The embodiments for carrying out the technology disclosed in this application will be described below with reference to the drawings.

[0012] (Embodiment 1) -Overall structure of the ball valve- FIG. 1 is a diagram schematically showing the appearance of the ball valve 1 according to the present embodiment. This ball valve 1 is applied to, for example, a steam system in which steam flows through a pipe, and is configured as a three-way valve having an inflow port 3a to which an inflow pipe IP is connected, a first outflow port 3b to which a first outflow pipe OP1 is connected, and a second outflow port 3c to which a second outflow pipe OP2 is connected.

[0013] By rotating the handle 50, the ball valve 1 is configured to switch between a fully open state in which the steam flowing into the inflow port 3a mainly flows out from the first outflow port 3b, a fully closed state in which the fluid flow is blocked, and an orifice discharge state in which the drain mainly contained in the steam is discharged from the second outflow port 3c. Hereinafter, the configuration of the ball valve 1 that can be switched to such three states will be described in detail.

[0014] FIG. 2 is a cross-sectional view schematically showing the ball valve 1, and FIG. 3 is a cross-sectional view schematically showing the ball valve 1 in a state where the valve body 20 is rotated from the state shown in FIG. 2. FIG. 4 is a cross-sectional view taken along the arrow IV-IV in FIG. 2, FIG. 5 is a cross-sectional view taken along the arrow V-V in FIG. 3, and FIG. 6 is a cross-sectional view in a state where the valve body 20 is rotated 180° from the state shown in FIG. 5. In FIG. 3, the handle 50 is not shown for easy viewing, and in FIGS. 4 to 6, the casing 3 is not shown for easy viewing.

[0015] When the ball valve 1 is applied to a steam system, since the ball valve 1 is used in a mode where the valve shaft 30 extends vertically, hereinafter, for convenience, based on such a use state, the direction in which the Z-axis shown in each figure extends (the direction in which the valve shaft 30 extends) is defined as the "vertical direction", the positive side of the Z-axis is defined as the "upper side", the negative side of the Z-axis is defined as the "lower side", and the direction in which the X-axis shown in each figure extends, which is orthogonal to the Z-axis, and the direction in which the Y-axis shown in each figure extends, which is orthogonal to the Z-axis and the X-axis, are defined as the "horizontal direction" for explanation.

[0016] In this embodiment, "vertical direction," "upper side," "lower side," and "horizontal direction" are used to explain the relative positional relationships of each part, and do not limit the orientation or posture of the ball valve 1 when it is applied to a system in which a fluid other than steam (air, water, hot water, etc.) flows through the piping.

[0017] As shown in Figures 2 and 3, the ball valve 1 comprises a casing 3 in which a valve chamber 9 is provided, a valve body 20 housed in the valve chamber 9, a valve shaft 30 that rotatably supports the valve body 20 relative to the casing 3, and an operating handle 50 connected to the valve shaft 30.

[0018] -Casing- The casing 3 has a main body 5 and a flange 7 that is attached to the main body 5 from one horizontal side (the left side in Figures 2 and 3) with an annular gasket 8 sandwiched between them. The inlet port 3a and the first outlet port 3b, which constitute the flow path for the fluid (steam, etc.) in the casing 3, are formed in the flange 7 and the main body 5, respectively, so as to extend horizontally. The valve chamber 9 is formed in the casing 3 as a cylindrical space extending horizontally, located in the middle of the flow path, specifically between the inlet port 3a and the first outlet port 3b. The main body 5 has a circular cross-section communication hole 5a that extends horizontally to connect the valve chamber 9 and the first outlet port 3b. On the other hand, the flange 7 has a circular cross-section communication hole 7a that extends horizontally to connect the valve chamber 9 and the inlet port 3a.

[0019] The inlet port 3a, communication hole 7a, valve chamber 9, communication hole 5a, and first outlet port 3b are formed such that their axes form a straight line when the flange portion 7 is assembled to the main body portion 5. This imaginary straight line formed by these axes will be tentatively referred to as the "first imaginary line." In Figures 2 and 3, this first imaginary line coincides with the X-axis.

[0020] The second outlet port 3c is formed at the lower end of the main body 5 so as to extend vertically. Below the valve chamber 9 in the main body 5, a support hole 5b with a circular cross-section is formed so as to communicate with the valve chamber 9 and the second outlet port 3c, extending vertically. The support hole 5b communicates with the second outlet pipe OP2 (outside the casing 3) via the second outlet port 3c. Furthermore, as will be described later, the valve stem 30 is inserted into this support hole 5b. Therefore, in relation to the claims, the support hole 5b in this embodiment corresponds to the "support hole that allows the valve stem to be inserted and leads from the valve chamber to the outside of the casing" as described in the claims.

[0021] Furthermore, in the portion of the main body 5 above the valve chamber 9, a bearing hole 5c with a circular cross-section is formed, extending upward from the valve chamber 9 and penetrating the portion. A cylindrical wall portion 5d is also formed extending upward from a position radially outside the bearing hole 5c. The second outlet port 3c, support hole 5b, bearing hole 5c, and cylindrical wall portion 5d are formed so that their axes form a straight line. This imaginary straight line formed by these axes will be tentatively referred to as the "second imaginary line." In Figures 2 and 3, this second imaginary line coincides with the Z-axis.

[0022] - Valve body - The valve body 20 is formed in a spherical shape. As shown in Figures 2 to 6, the valve body 20 has a through hole 21 with a circular cross-section that penetrates the valve body 20 horizontally. The through hole 21 is formed to the same diameter as the communication holes 5a and 7a, and its axis passes through the center of the valve body 20.

[0023] Furthermore, the valve body 20 has a branch hole 23 with a circular cross-section whose axis passes through the center of the valve body 20 and perpendicular to the through hole 21. More specifically, as shown in Figures 4 to 6, the branch hole 23 branches perpendicularly from the center of the through hole 21, extends horizontally, and opens on the surface 20a of the valve body 20. The branch hole 23 is formed to have the same diameter as the communication holes 5a and 7a, similar to the through hole 21. A screen 27 for removing foreign matter from the fluid is provided in this branch hole 23.

[0024] Furthermore, the valve body 20 has two circular rotating shaft holes 25 that extend vertically and penetrate the valve body 20, with their axes passing through the center of the valve body 20 and perpendicular to the through hole 21 and the branch hole 23, sandwiching the through hole 21 from above and below. Both rotating shaft holes 25 are formed to be smaller in diameter than the through hole 21 and the branch hole 23. The upper rotating shaft hole 25 has a keyway 25a that engages with the spindle 33 of the valve stem 30 in order to prevent relative rotation between the valve stem 30 inserted into the rotating shaft hole 25 and the valve body 20.

[0025] Since the valve stem 30, which is inserted through a vertically extending support hole 5b, is inserted into the rotating shaft hole 25 in a way that prevents relative rotation, the valve body 20 is rotatable around the valve stem 30 (vertically) relative to the casing 3. Furthermore, the valve body 20 is housed in the valve chamber 9 such that its center coincides with the intersection of the first and second imaginary lines. As a result, the orientation of the through hole 21 and branch hole 23 changes as the valve body 20 rotates, while the axes of the through hole 21 and branch hole 23 and the axes of the inlet port 3a, communication hole 7a, communication hole 5a, and first outlet port 3b are located on the same plane.

[0026] The valve body 20, configured as described above, is housed in the valve chamber 9, sandwiched horizontally between a pair of annular valve seats 10, each having an opening in the center with the same diameter as the communication holes 5a and 7a. More specifically, the valve body 20, along with a pair of annular disc springs 11, a pair of annular washers 13, and a pair of valve seats 10, is inserted into the valve chamber 9 from one horizontal side (the left side in Figures 2 and 3) in the order of disc spring 11, washer 13, valve seat 10, valve body 20, valve seat 10, washer 13, and disc spring 11. After the flange portion 7 is assembled to the main body portion 5, the valve seats 10 are housed in the valve chamber 9, pressed horizontally against each other by the biasing force of the disc springs 11. In this way, the valve seats 10 are pressed against the valve body 20, causing the surface 20a of the valve body 20 and the valve seats 10 to be in close contact, thereby maintaining airtightness between the surface 20a of the valve body 20 and the valve seats 10. In Figures 2 and 3, reference numeral 15 indicates an O-ring attached to the outer circumference of the valve seat 10 to prevent fluid leakage from the gap between the valve seat 10 and the casing 3.

[0027] In the ball valve 1 according to this embodiment, which has a valve body 20 configured in this way, by rotating the valve body 20 so that the axis of the through hole 21 coincides with the first imaginary line, it is possible to achieve a fully open state (first state) in which the inlet port 3a (inlet side) and the first outlet port 3b (outlet side) communicate through the through hole 21, as shown in Figure 4.

[0028] Furthermore, when the ball valve 1 is rotated 90° clockwise in Figure 4 from this fully open state, as shown in Figure 5, the first outlet port 3b side (outlet side) is closed on the surface 20a of the valve body 20 where the through hole 21 and branch hole 23 are not open, and the through hole 21 is connected to the inlet port 3a side (inlet side) via the branch hole 23, switching to an orifice discharge state (second state). Note that since both outer sides of the valve chamber 9 in the Y-axis direction are blocked by the side walls of the casing 3 (not shown), fluid flowing in from the inlet port 3a via the branch hole 23 does not flow out horizontally from the through hole 21.

[0029] Furthermore, when the ball valve 1 is rotated 180° from the state shown in Figure 5, it switches to a fully closed state (third state) as shown in Figure 6, where the inlet port 3a side is closed on the surface 20a of the valve body 20 where the through hole 21 and branch hole 23 are not open.

[0030] -Valve shaft- The valve stem 30 includes a valve stem 31 inserted into two rotating shaft holes 25 of the valve body 20, and a spindle 33 that fits into the keyway 25a of the valve body 20 through a bearing hole 5c. The valve stem 31 is formed in a cylindrical shape without steps, while the spindle 33 is formed in a cylindrical shape with multiple stepped sections and has a flange portion 33a whose outer diameter is larger than the inner diameter of the bearing hole 5c. The valve stem 31 and the spindle 33 are connected such that the axis of the valve stem 31 and the axis of the spindle 33 are in a straight line.

[0031] As shown in Figures 2 and 3, the valve stem 31 passes through the valve body 20 vertically through the through hole 21. The valve stem 31 has an orifice passage 35 that is smaller in diameter than the through hole 21, which communicates with the through hole 21 when the valve stem 30 is assembled to the casing 3, and extends axially within the valve stem 31 to communicate with the outside of the casing 3. The orifice passage 35 has a first passage 35a that penetrates the valve stem 31 radially and a second passage 35b that extends axially within the valve stem 31, and is formed to form a T shape when viewed from the Y-axis direction in the orifice discharge state shown in Figure 3.

[0032] More specifically, the first flow path 35a is formed to penetrate the valve stem 31 radially (horizontally) at a position lower than the axis of the through-hole 21 in the portion of the valve stem 31 that passes through the through-hole 21 when the valve stem 30 is assembled to the casing 3, and to open on the surface 31a of the valve stem 31. In contrast, the second flow path 35b is formed to extend axially (downward) from the central part of the first flow path 35a through the valve stem 31 and communicate with the outside of the casing 3 by communicating with the second outlet port 3c.

[0033] The valve stem 30, configured as described above, is assembled to the casing 3 from top to bottom such that the tip of the valve stem 31 is inserted into the support hole 5b by passing through the bearing hole 5c and the rotational shaft hole 25 in that order. At this time, the tip of the valve stem 31 is inserted into the support hole 5b so as to be rotatable relative to it via the cylindrical metal 37. The spindle 33 is fitted into the keyway 25a formed in the valve body 20 such that the first flow path 35a formed through the valve stem 31 extends in a direction different from the through hole 21, specifically, in the same direction as the branch hole 23.

[0034] Prior to assembling the valve stem 30 to the casing 3, an annular disc spring 38, an annular washer 39, and the flange portion of a hat-shaped gland seat 40 are installed on the upper side of the periphery of the bearing hole 5c, in this order from bottom to top. An annular gasket 41 is also installed between the disc spring 38 and the cylindrical wall portion 5d. In this state, when the spindle 33 is fitted into the keyway 25a, the flange portion 33a of the spindle 33 sits on the flange portion of the gland seat 40, thereby biasing the valve stem 30 upward by the disc spring 38.

[0035] Then, an annular packing 42, an annular seal 43, and a cylindrical sliding tube 44 are fitted onto the spindle 33 in that order from bottom to top on each stepped portion above the flange portion 33a, and a holder 45 is placed over the spindle 33 from above, and the holder 45 is fixed to the cylindrical wall portion 5d with a set screw 47. As a result, the valve stem 30 is biased upward by the disc spring 38, suppressing vertical play (looseness), while the holder 45 prevents the valve stem 30 from popping out.

[0036] -handle- As shown in Figures 1 and 2, the handle 50 has a handle body portion 51 that is gripped by the operator and a cylindrical cover portion 53. The handle 50 is installed on the upper end of the spindle 33 such that the cover portion 53 covers the cylindrical wall portion 5d from above, and then fastened to the upper end of the spindle 33 with a bolt 55. Reference numeral 57 in Figure 2 indicates a disc spring washer that prevents the bolt 55 from loosening, and reference numeral 59 in Figure 2 indicates a bush that prevents wear of the bolt 55 due to repeated rotational operation.

[0037] -Fluid flow- Next, we will describe the fluid (steam, drain) flow in the fully open state and the orifice discharge state when the ball valve 1 is applied to a steam system.

[0038] ≪Fully open≫ First, we will explain the case where the valve is fully open and primarily steam flows through the piping. Figure 7 is a schematic diagram showing the steam flow inside the ball valve 1 in the fully open state, and Figure 8 is a cross-sectional view taken along the line VIII-VIII in Figure 7. In the fully open state, as shown in Figure 4 above, the inlet port 3a and the first outlet port 3b are in communication through the through hole 21, and as shown by the white arrows in Figure 7, a large flow rate of steam can be passed through the ball valve 1 from the inlet port 3a side (inlet side) to the first outlet port 3b side (outlet side). As a result, for example, if the ball valve 1 is fully opened when starting up the steam system, it becomes possible to remove (blow out) foreign matter adhering to the piping without having to perform complicated cleaning work such as dismantling the piping.

[0039] Here, since the valve stem 31 has an orifice passage 35 that communicates with the through hole 21 and also with the outside of the casing 3, it is thought that in the fully open state, steam will leak to the second outlet port 3c through this orifice passage 35, increasing leakage loss. However, as shown by the white arrow in Figure 8, when a large flow rate of steam is flowing from the inlet port 3a to the first outlet port 3b, it is difficult to imagine a flow that changes direction at a right angle as shown by the dashed line in Figure 8 occurring.

[0040] In this regard, in the ball valve 1 according to this embodiment, the first flow path 35a communicating with the through hole 21 extends in a direction different from the through hole 21, specifically in a direction perpendicular to the through hole 21, and opens on the surface 31a of the valve stem 31. Therefore, in the fully open state, steam flowing from the inlet side to the outlet side through the through hole 21 is less likely to enter the first flow path 35a. As a result, when it is desired to actively flow steam from the inlet side to the outlet side, leakage of steam from the orifice flow path 35 can be suppressed.

[0041] Next, we will explain the case where steam and condensate flow through the piping in the fully open state. Figure 9 is a schematic diagram showing the flow of steam and condensate inside the ball valve 1 in the fully open state. Note that the symbol WS in Figure 9 indicates the water level of the condensate. When both steam and condensate flow through the piping, as shown by the white arrows in Figure 9, the steam flows in the upper part of the piping, while as shown by the black arrows in Figure 9, the condensate flows in the lower part of the piping.

[0042] In this respect, in the ball valve 1 according to this embodiment, since the first flow path 35a is located lower than the axis of the through hole 21, the drain flowing in the lower part of the through hole 21 can be discharged to the outside of the casing 3 through the first flow path 35a and the second flow path 35b, as shown by the hatched arrows in Figure 9. Therefore, it is possible to discharge unnecessary drain to the second outlet pipe OP2 while a large flow rate of steam is flowing from the inlet port 3a to the first outlet port 3b.

[0043] <<Orifice discharge state>> Figure 10 schematically shows the flow of drain water inside the ball valve 1 in the orifice discharge state. In the orifice discharge state, the first outlet port 3b side (outlet side) is closed on the surface 20a of the valve body 20 where the through hole 21 and branch hole 23 are not open. However, since a branch hole 23 is formed in the valve body 20 that branches off from the through hole 21 and opens on the surface 20a of the valve body 20 to communicate with the inlet port 3a (inlet side), steam (see white arrow) and drain water (see black arrow) flow into the through hole 21 through the branch hole 23, as shown in Figure 10.

[0044] Thus, an orifice passage 35 is formed in the valve stem 30, which communicates with the through hole 21 and extends downward (axially) within the valve stem 30, communicating with the outside of the casing 3 via the second outflow port 3c. As shown by the hatched arrow in Figure 10, drain can be discharged from the ball valve 1 through the orifice passage 35. At that time, since a screen 27 is provided in the branch hole 23 that connects the inflow port 3a and the through hole 21, it is possible to prevent the orifice passage 35, which has a smaller diameter than the through hole 21, from being blocked by foreign matter.

[0045] Furthermore, when the drain water level WS falls below the first flow path 35a, steam inevitably flows from the ball valve 1 to the second outlet pipe OP2 through the orifice flow path 35. However, since the orifice flow path 35 is formed with a smaller diameter than the through hole 21, it is possible to suppress an excessive increase in leakage loss.

[0046] As described above, in the ball valve 1 according to this embodiment, an orifice passage 35 that enables a small flow rate (drain discharge) in addition to a large flow rate of fluid flowing from the inlet side to the outlet side can be realized by a simple configuration in which a passage with a smaller diameter than the through hole 21 is formed on the valve stem 30, which is necessary for rotating the valve body 20 and whose position does not change even when the valve body 20 is rotated. In other words, an orifice passage 35 that enables flow rate switching can be realized.

[0047] Furthermore, in the ball valve 1 according to this embodiment, by simply rotating the valve body 20, it is possible to easily achieve a fully open state (first state) in which a large flow rate of fluid flows from the inlet side to the outlet side, an orifice discharge state (second state) in which a small flow rate of fluid flows out through the orifice passage 35, and a fully closed state (third state) in which the fluid flow is stopped, as shown in Figure 6 above.

[0048] In addition to these, the ball valve 1 according to this embodiment is configured as a so-called ball butterfly valve in which the valve stem 30 penetrates the valve body 20, and therefore has the following advantages.

[0049] First, in this embodiment, the ball valve 1 has a valve stem 30 that penetrates the valve body 20 and is supported by the casing 3 at two locations (support hole 5b and bearing hole 5c) above and below the valve chamber 9. Therefore, the valve stem 30 is less likely to tilt than in a typical ball valve where the valve body is supported by the casing on only one side. Consequently, vibration of the valve body 20 due to high-pressure fluid is suppressed, making it suitable for use even in high-pressure environments.

[0050] Figure 11 is a schematic diagram illustrating the procedure for changing the diameter of the orifice passages 35 and 65. In this embodiment, the ball valve 1 employs a configuration in which the valve stem 30, to which the valve stem 31 and spindle 33 are connected, passes through the valve body 20. This allows the valve stem 30 to be easily replaced, thereby allowing the diameter of the orifice passage 35 to be easily changed.

[0051] Specifically, as indicated by arrow A in Figure 11, the set screw 47 for fixing the holder 45 to the casing 3 is removed, and then, as indicated by arrow B in Figure 11, the holder 45 is removed from the casing 3. Next, as indicated by the white arrow C in Figure 11, the valve stem 30 is removed from the casing 3, and as indicated by arrow D in Figure 11, the slide tube 44, seal 43, and packing 42 are removed from the removed valve stem 30.

[0052] Thus, a valve stem 60 is prepared that has the same external shape as the valve stem 30, but has an orifice passage 65 with a larger diameter than the orifice passage 35. After attaching the packing 42, seal 43, and slide tube 44 to this valve stem 60 as shown by arrow E in Figure 11, the valve stem 60 is inserted into the casing 3 as shown by the black-filled arrow F in Figure 11. Next, after fitting the holder 45 into the casing 3 as shown by arrow G in Figure 11, the holder 45 is fixed to the casing 3 with a set screw 47 as shown by arrow H in Figure 11. In this way, by preparing valve stems 60 with different diameters of orifice passages 65, a ball valve 1 having orifice passages 65 of different diameters can be easily realized.

[0053] <Variation> In this modified example, the shape of the portion of the valve stem passing through the through-hole 21 differs from that of Embodiment 1. The following description will focus on the differences from Embodiment 1.

[0054] Figure 12 schematically shows the valve stem 70 according to this modified example. The dashed circle in Figure 12 shows the outer shape of the portion of the valve stem 71 of the valve stem 70 that does not pass through the through hole 21. The white arrows in Figure 12 indicate the fluid flow.

[0055] As described above, in Embodiment 1, the ball valve 1 is configured as a ball butterfly valve. However, in a ball butterfly valve in which a portion of the valve stem 31 passes through the through hole 21, the resistance to the fluid passing through the interior is greater than in a general ball valve in which the valve stem does not pass through the through hole, due to the generation of vortices downstream of the valve stem 31. However, even in a ball butterfly valve, the portion of the valve stem other than the portion that is rotatably supported by the casing 3, specifically the portion inserted into the support hole 5b, does not necessarily need to have a circular cross-section.

[0056] Therefore, in this modified example, the cross-sectional shape of the portion of the valve stem 71 of the valve shaft 70 that passes through the through hole 21 (hereinafter also referred to as the "in-hole valve stem portion 72") is formed to have a streamlined shape that extends in the same direction as the through hole 21. More specifically, as shown in Figure 12, the in-hole valve stem portion 72 extends elongated in the direction of the fluid flow, which is the direction in which the through hole 21 extends, and has a cross-sectional shape in which the tip on the inlet side is rounded and the rear end on the outlet side is pointed.

[0057] Thus, because the cross-sectional shape of the valve stem portion 72 inside the hole has a streamlined shape extending in the same direction as the through hole 21, the fluid that hits the valve stem portion 72 inside the hole flows downstream along the surface of the valve stem portion 72 to the rear end, as shown by the hatched arrows in Figure 12, without generating vortices, thus suppressing an increase in resistance to the fluid.

[0058] Furthermore, since the in-hole valve stem portion 72 is contained within the dotted circle in Figure 12, that is, within the outer shape of the portion of the valve stem 71 that does not pass through the through-hole 21, the valve stem 70 can be easily replaced, similar to Embodiment 1, even if the cross-sectional shape of the in-hole valve stem portion 72 is not circular. This makes it possible to easily change the diameter of the orifice flow path 75 while suppressing an increase in resistance to the fluid.

[0059] In Figure 12, the cross-sectional shape of the valve stem portion 72 inside the bore is generally given as a streamlined shape, which is "rounded at the tip, pointed at the rear end, and elongated overall." However, if the resistance is lower than that of a valve stem with a circular cross-section, the cross-sectional shape of the valve stem portion 72 inside the bore may be an elliptical shape with its major axis extending in the direction of the through-hole 21. Also, in Figure 12, the entire cross-sectional shape of the valve stem portion 72 inside the bore is given as a general streamlined shape. However, if the resistance is lower than that of a valve stem with a circular cross-section, the cross-sectional shape of the valve stem portion 72 inside the bore may be a cross-sectional shape that has a streamlined shape in part.

[0060] (Embodiment 2) This embodiment differs from Embodiment 1 in that the valve stem and spindle constituting the valve shaft are separated, and the valve stem and valve body are integrally formed. The following description will focus on the differences from Embodiment 1.

[0061] Figure 13 is a schematic cross-sectional view showing a ball valve 1 according to Embodiment 2. Note that the ball valve 1 illustrated in Figure 13 has substantially the same configuration as Embodiment 1, except for the valve body 80 and valve stem 90. Therefore, the same reference numerals are used for the same components as in Embodiment 1, and their descriptions are omitted.

[0062] - Valve body - As shown in Figure 13, the valve body 80 is formed in a spherical shape and has a through hole 81 corresponding to the through hole 21 and a branch hole 83 corresponding to the branch hole 23, similar to the valve body 20 of Embodiment 1.

[0063] However, unlike the valve body 20 of Embodiment 1, the valve body 80 has a circular cross-section rotating shaft hole 85 formed only in the upper part of the valve body 80, with its axis passing through the center of the valve body 80 and perpendicular to the through hole 81 and the branch hole 83. Also, unlike the rotating shaft hole 25 of Embodiment 1, the rotating shaft hole 85 does not penetrate the upper part of the valve body 80, but opens only upward. Furthermore, the valve body 80 differs from the valve body 20 of Embodiment 1 in that, instead of a rotating shaft hole, a valve stem 91 is integrally formed in the lower part of the valve body 80 that is vertically opposite to the rotating shaft hole 85.

[0064] -Valve shaft- The valve stem 90 has a valve stem (lower shaft portion) 91 and a spindle 93 (upper shaft portion) separated from the valve stem 91.

[0065] The spindle 93 is formed in a cylindrical shape with multiple stepped sections. The lower end of the spindle 93 is fitted in a way that prevents relative rotation with the rotational shaft hole 85 formed in the valve body 80 in the portion above the through hole 81. Therefore, in relation to the claims, the spindle 93 of this embodiment corresponds to the "upper shaft portion extending upward from the portion above the through hole" as described in the claims.

[0066] The valve stem 91 is formed in a cylindrical shape without any steps. The upper half of the valve stem 91 is integrally formed with the valve body 80 such that its upper end is flush with the lower end of the through hole 81. On the other hand, the lower half of the valve stem 91 has its tip inserted into the support hole 5b via the metal 37 so as to be rotatable relative to it. Therefore, in relation to the claims, the valve stem 91 of this embodiment corresponds to the "lower shaft portion extending downward from the lower end of the through hole" as described in the claims.

[0067] The valve stem 91 has an orifice passage 95 that is smaller in diameter than the through hole 81. This orifice passage 95 communicates with the through hole 81 when the valve stem 90 is assembled to the casing 3, and extends axially within the valve stem 91 to communicate with the outside of the casing 3. Specifically, the orifice passage 95 is formed to pass through the valve stem 91 vertically, connecting the through hole 81 and the outside of the casing 3 in a straight line.

[0068] In the ball valve 1 according to this embodiment, an orifice flow path 95 that enables flow rate switching can be realized with an even simpler configuration, which involves forming a small-diameter flow path that penetrates the valve stem 91 vertically.

[0069] Furthermore, in the ball valve 1 according to this embodiment, the valve body 80 is supported by the spindle 93 and the valve stem 91 (at two locations, upper and lower). This allows for the suppression of vibration of the valve body 80 due to high-pressure fluid, similar to a ball butterfly valve. In addition, unlike a ball butterfly valve, the valve stem 90 does not pass through the through hole 81, thus preventing an increase in resistance to the fluid flowing through the through hole 81.

[0070] Furthermore, since the orifice passage 95 penetrates the valve stem 91 vertically, or in other words, extends perpendicular to the through-hole 81, when fully open, steam flowing from the inlet port 3a (inlet side) to the first outlet port 3b (outlet side) via the through-hole 81 is less likely to enter the orifice passage 95. This makes it possible to suppress steam leakage from the orifice passage 95 when it is desired to actively flow steam from the inlet side to the outlet side.

[0071] Furthermore, since the orifice flow path 95 is in communication with the through-hole 81 at the upper end of the valve stem 91 (the lower end of the through-hole 81), the drain accumulated at the bottom of the through-hole 81 can be reliably discharged when the orifice is discharged.

[0072] (Other embodiments) The technology disclosed herein is not limited to its embodiments and can be implemented in various other ways without departing from its spirit or main features.

[0073] In the embodiments and modifications described above, the technology of this disclosure is applied to a steam system in which steam flows through a pipe. However, the technology is not limited to this, and may also be applied to a system in which a fluid such as air, water, or hot water flows through a pipe. In this case, a large flow rate of fluid can be passed through the through-holes 21 and 81 in the fully open state, while a small flow rate of fluid can be passed through the orifice passages 35, 65, 75, and 95 in the orifice discharge state. In this case, it is not necessary to consider the discharge of drain flowing in the lower part of the pipe. In other words, it is not necessary to set the orifice passages 35, 65, 75, and 95 at a low position in the ball valve 1, so it is not necessary to align the direction in which the valve stems 30, 70, and 90 extend with the vertical direction.

[0074] Furthermore, in the above embodiment 1, the orifice flow path 35 was formed to form a T-shape when viewed from the Y-axis direction in the orifice discharge state shown in Figure 3. However, it is not limited to this, as long as it communicates with the through hole 21 and with the outside of the casing 3, for example, as shown in Figure 14, the first flow path 35a may be formed so as not to penetrate the valve stem 31, and the orifice flow path 35 may be formed to form an inverted L-shape when viewed from the Y-axis direction. In this case as well, drain can be discharged from the ball valve 1 through the orifice flow path 35, as indicated by the hatched arrow in Figure 14.

[0075] Furthermore, in the above embodiment 2, the valve stem 91 and the valve body 80 are formed integrally, but the invention is not limited to this. For example, the valve stem, which is formed separately from the valve body, may be connected to the valve body in a way that prevents relative rotation.

[0076] Furthermore, in each of the above embodiments, the through holes 21, 81 and branch holes 23, 83 were formed so that their axes pass through the center of the valve bodies 20, 80 and extend in a straight line. However, the invention is not limited to this, for example, the axes of the through holes 21, 81 and branch holes 23, 83 may not pass through the center of the valve bodies 20, 80, or the through holes 21 and branch holes 23 may be formed in a curved shape, as schematically shown in Figure 15.

[0077] Thus, the embodiments described above are merely illustrative in all respects and should not be interpreted restrictively. Furthermore, any variations or modifications that fall within the equivalent scope of the claims are all within the scope of this disclosure. [Industrial applicability]

[0078] As described above, the technology disclosed in this application is extremely useful when applied to ball valves. [Explanation of Symbols]

[0079] 1 Ball valve 3. Casing 3a Inflow port (flow path) 3b First outflow port (flow channel) 5a, 7a Communication hole (flow path) 5b Support hole 9 valve chambers 20, 80 valve bodies 20a surface 21, 81 through holes 23, 83 branch holes 27 screens 30, 60, 70, 90 valve stem 31a surface 35, 65, 75, 95 orifice channels 35a First channel 35b Second channel 72. Valve stem portion inside the hole (the part that passes through the through hole) 91 Valve stem (lower shaft) 93 Spindle (upper shaft section)

Claims

1. A ball valve comprising a casing having a fluid passage and a valve chamber provided in the middle of the passage, a spherical valve body with a through hole housed in the valve chamber, and a valve shaft that rotatably supports the valve body relative to the casing, wherein by rotating the valve body, the valve valve switches between a first state in which the inlet and outlet sides of the passage are in communication through the through hole, and a second state in which the outlet side of the passage is closed by the non-opening surface of the valve body, The casing has a support hole formed therein, into which the valve stem is inserted, and which leads from the valve chamber to the outside of the casing. The valve body has a branch hole that branches off from the through hole and opens on the surface of the valve body, such that in the second state, the inlet side of the flow path and the through hole are in communication with each other. A ball valve characterized in that the valve stem has an orifice passage formed therein, which communicates with the through hole and extends axially within the valve stem, communicating with the outside of the casing, and which has an orifice passage smaller in diameter than the through hole.

2. In the ball valve described in claim 1, The valve stem extends vertically and passes through the valve body so as to pass through the through hole. The ball valve is characterized in that the orifice passage has a first passage that extends in a direction different from the through-hole and opens on the surface of the valve stem at a position lower than the axis of the through-hole in the portion of the valve stem that passes through the through-hole, and a second passage that extends downward from the first passage inside the valve stem and communicates with the outside of the casing.

3. In the ball valve described in claim 1, The valve stem passes through the valve body so as to pass through the through hole, A ball valve characterized in that the cross-sectional shape of the portion of the valve stem passing through the through hole has a streamlined shape extending in the same direction as the through hole.

4. In the ball valve described in claim 1, The valve stem has an upper shaft portion extending upward from the portion above the through hole, and a lower shaft portion extending downward from the lower end of the through hole. The ball valve is characterized in that the orifice passage penetrates the lower shaft portion vertically.

5. In the ball valve described in claim 1, A ball valve characterized in that it is configured to switch to a third state in which the inflow side of the flow path is closed at the surface of the valve body where the hole is not open.

6. In the ball valve described in claim 1, A ball valve characterized in that a screen for removing foreign matter from the fluid is provided in the branch hole.

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