Valve

Abstract

To provide a valve hardly causing looseness of a seat member formed with a valve seat when allowing high-temperature high-pressure fluid to flow.SOLUTION: A valve in which fluid channels 11, 12 and a valve chamber 13 having openings 17 of the fluid channels on a bottom face 14 are formed, includes: a seat member 20 arranged in a valve chamber and having a first male screw 23 engaged with a valve body 10 and cut on an outer peripheral surface; a valve element 4 abutted on and separated from the seat member; and a seat member presser 30 having a second male screw 33 engaged with the inner peripheral surface of the valve chamber and cut on the outer peripheral surface, and a through hole 32 into which a stem 3 having the valve element at the tip is inserted, and pressing the seat member. One of the seat member and the seat member presser has a male taper 21 projecting in an axial direction to the other side, and the other has a female taper 31 fitted to the male taper. The male taper and the female taper are eccentrically fitted due to that the central axis of the male taper and the central axis of the female taper are deviated from each other.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fluid control valve, and more particularly to a valve that is suitably used as an on-off valve for controlling high-temperature and high-pressure fluid. [Background technology]

[0002] Figure 5 shows the vicinity of the valve chest of the valve described in Patent Document 1. A valve seat body 101 is joined to a hole 123 of a valve body 102 having an inlet 121 and an outlet 122 by a male thread 112 screwing into a female thread 124 formed on the inner surface of the hole 123. The flow rate of the fluid flowing through the valve port 113 is controlled by the contact and separation between the valve body 104 and the valve seat 114. A gasket packing 103 is fitted to the underside of the flange 111 to prevent back leakage of the fluid. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 58-1878 Summary of the Invention [Problem to be solved by the invention]

[0004] 5, the valve seat body 101 is joined to the valve body 102 by the screwing of the male thread 112 and the female thread 124. If the screwing becomes loose, back leakage of the fluid will occur.

[0005] There are two modes of loosening of threads: loosening due to thread rotation and non-rotational loosening. Causes of loosening due to thread rotation include repeated loads in the axial direction, perpendicular direction, torsional direction, temperature change, bending moment, etc., and impact loads on the screw head, fastened object, etc.

[0006] Causes of non-rotational loosening of threads include plastic deformation of the thread, break-in of the fastened body, settling of the fastened body, temperature change, plastic deformation due to bending moment, etc., creep elongation of the thread, creep deformation such as compressive creep of the fastened body, and temperature change due to the difference in thermal expansion between the thread and the fastened body, change in elastic modulus due to thermal effects, etc.

[0007] These numerous causes are all intricately intertwined, and although loosening of the threads over time can be prevented by welding the valve seat 101 and the valve body 102 together, it is difficult to prevent back leakage when high-temperature, high-pressure fluids are being passed through them using only thread fastening and welding.

[0008] The object of the present invention has been made in consideration of the above-mentioned points, and its object is to provide a valve in which, when a high-temperature, high-pressure fluid is flowing, the seat member on which the valve seat is formed is unlikely to become loose, even if the seat member is separate from the valve body. [Means for solving the problem]

[0009] The present invention (1) made to solve the above problems is a valve comprising: a valve body having a fluid passage and a valve chamber with an opening of the fluid passage on its bottom surface; a seat member disposed in the valve chamber and having a passage communicating with the fluid passage, the seat member having a first male thread engraved on its outer peripheral surface which screws into the valve body; a valve body which abuts and separates from the seat member; a seat member presser which has a second male thread engraved on its outer peripheral surface which screws into the inner peripheral surface of the valve chamber and has a through hole through which a stem having the valve body at its tip is inserted, and which presses the seat member; wherein one of the seat member and the seat member presser has a male taper protruding in the axial direction toward the other, and the other has a female taper which engages with the male taper, the central axis of the male taper and the central axis of the female taper are misaligned, and the male taper and the female taper are eccentrically engaged with each other.

[0010] The first male thread of the seat member screws into the female thread formed on the valve body, fastening the seal member and the valve body without loosening. When fastening the screws, the fastening force is strongest when fastening, and decreases immediately after fastening or over time. To prevent loosening of the screws due to rotation and non-rotation, it is ideal to continue applying the biasing force when fastening, but in reality this is difficult.

[0011] Therefore, the present invention (1) comprises a seat member having a first male thread engraved on its outer peripheral surface which screws into the valve body, and a seat member holder having a second male thread engraved on its outer peripheral surface which screws into the inner peripheral surface of the valve chamber and which presses the seat member, wherein one of the seat member and the seat member holder has a male taper that protrudes axially toward the other, and the other has a female taper that mates with the male taper, and the central axis of the male taper and the central axis of the female taper are misaligned, so that the male taper and the female taper mate eccentrically.

[0012] With this structure, by screwing the seat member retainer into the female thread formed in the valve chamber, the male taper and female taper are eccentrically engaged, a thrust force is applied to the upper part of the seat member, a reaction force of this thrust force is generated in the first thread portion, and the first thread portion is pressed against the female thread of the valve body in a direction perpendicular to the axis, effectively preventing loosening of the thread and the occurrence of micromotion. In this way, the valve of the present invention (1) can prevent loosening of rotating and non-rotating threads, and provides a valve in which loosening of the seat member is unlikely to occur even if the seat member on which the valve seat is formed is separate from the valve body when high-temperature and high-pressure fluid is flowed.

[0013] The present invention (2) is the valve of the present invention (1), wherein the seat member has a flange portion facing the bottom surface, and a seal member is interposed between the lower surface of the flange portion and the bottom surface. In the present invention (2), a flange portion is provided facing the bottom surface, and a seal ring is interposed between the underside of the flange portion and the bottom surface. This makes it possible to prevent the seat member from loosening when flowing high-temperature, high-pressure fluid, etc., and prevents back leakage.

[0014] The present invention (3) is the valve according to the present invention (2), wherein the seal member is a hollow seal ring made of metal.

[0015] In the present invention (3), since the seal ring is a hollow seal ring made of metal, the seat member is less likely to become loose when a high-temperature, high-pressure fluid is passed through it, and back leakage can be prevented. Effect of the Invention

[0016] According to the present invention, it is possible to provide a valve in which, when a high-temperature, high-pressure fluid is passed through, the seat member on which the valve seat is formed is unlikely to come loose even if the seat member is separate from the valve body. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a partial cross-sectional view of a first embodiment of a valve according to an embodiment of the present invention, illustrating the entirety of the valve. [Diagram 2] 1 is a cross-sectional view showing a portion of a valve according to a first embodiment. [Diagram 3] FIG. 2 is a perspective view showing a part of the valve of the first embodiment. [Figure 4] FIG. 6 is a cross-sectional view showing a part of a valve according to a second embodiment. [Diagram 5] FIG. 1 is a cross-sectional view showing a portion of a conventional valve. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the following embodiments are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or its uses.

[0019] Fig. 1 shows an overall view of a partial cross section of a valve according to a first embodiment of the present invention. The valve 1 controls the flow of a fluid by contacting and separating a valve element 4 attached to the tip of a stem 3 connected to an actuator 2 and a seat member 20 on which a valve seat abutment surface 24 is formed. An inlet passage (fluid passage) 11 and an outlet passage (fluid passage) 12 are formed in a valve body 10, and a valve chamber 13 is formed between the inlet passage 11 and the outlet passage 12. An opening 17 of the inlet passage (fluid passage) 11 is formed in a bottom surface 14.

[0020] The seat member 20 is provided with a passage 22 that communicates with the fluid passage 11, and a first male thread 23 that screws into the valve body 10 is engraved on the outer circumferential surface at the lower part. A seat member holder 30 is disposed on the upper part of the seat member 20. A bonnet 5, through which the stem 3 is inserted, is fixed to the valve body 10 by a fixing screw 6, and the bonnet 5 is connected to the actuator 2 by a yoke 7.

[0021] Fig. 2 is a cross-sectional view showing a part of the valve of the first embodiment. Fig. 2(A) shows the state before the seat member holder 30 is assembled to the seat member 20 connected to the valve body 10, and Fig. 2(B) shows the state after assembly. Some parts already explained in Fig. 1 will not be explained again. A male taper 21 is formed on the seat member 20, and its surface serves as a male taper abutment surface 25. A first male thread 23 is screwed into a female thread (no reference number) engraved on the valve body 10. This screwing is performed by applying a special tool to the cutout surface 28 and applying the required tightening torque.

[0022] The seat member 20 is formed with a flange portion 26, and a metal seal member 16 is interposed between its lower surface 27 and the bottom surface 14 of the valve chamber 13. The seal member 16 is preferably a hollow seal ring, and is preferably made of stainless steel or the like. The upper end portion of the seat member 20 is formed with a valve seat abutment surface 24 that abuts against and separates from the valve body 4. A valve chamber female thread 15 is engraved on the inner peripheral surface of the valve chamber 13 to be screwed with a second male thread 33 of the seat member retainer 30.

[0023] The seat member retainer 30 has a through hole 32 through which the stem 3 passes, and a second male thread 33 is engraved on its outer circumferential surface to screw into the valve chest female thread 15. A female taper 31 that engages with the male taper 21 is formed on the lower part of the seat member retainer 30, and the female taper abutment surface 34 abuts against the male taper abutment surface 25.

[0024] As shown in Figure 2(B), when the sheet member retainer 30 is screwed in and taper-fitted with the sheet member 20, the central axis of the male taper 21 is misaligned with the central axis of the female taper 31, so that the left side of the taper joint is in contact as shown in the figure, but there is a gap on the right side. This figure is exaggerated for ease of understanding, but in reality there is only a very slight eccentricity, so there is no such big difference.

[0025] By strongly screwing in the seat member retainer 30, a force acts from the female taper abutment surface 34 to strongly press the male taper 21 to the right, and as a reaction to this force, the left side of the first male thread 23 is pressed leftward against the female thread (no symbol) engraved on the valve body 10. This pressing force prevents the first male thread 23 from loosening and micromotion.

[0026] Fig. 3(A) is a perspective view of the sheet member presser 30 shown in Fig. 2 when viewed obliquely from below, and Fig. 3(B) is a perspective view of the sheet member 20 shown in Fig. 2 when viewed obliquely from above. As this is the same as that described in Fig. 2, the description will be omitted.

[0027] Fig. 4 is a cross-sectional view showing a part of the valve of embodiment 2. Unlike embodiment 1, a male taper 51 is formed in the seat member retainer 50, and a female taper 41 is formed in the seat member 40. As shown in Fig. 4(A), a second male thread 53 is formed in the seat member retainer 50, and a through hole 52 is formed. The surface of the male taper 51 is a male taper abutment surface 55.

[0028] The seat member 40 is formed with a female tapered abutment surface 45, a cutout surface 48, a flange portion 46, a lower surface 47, a first male thread 43, a passage 42, and a valve seat abutment surface 44.

[0029] As shown in Figure 4(B), when the sheet member retainer 50 is screwed in and taper-fitted with the sheet member 40, the central axis of the male taper 51 is misaligned with the central axis of the female taper 41, so that the left side of the taper joint is in contact as shown in the figure, but there is a gap on the right side. This figure is exaggerated for ease of understanding, but in reality there is only a very slight eccentricity, so there is no such big difference.

[0030] By strongly screwing in the seat member retainer 50, a force acts from the male taper abutment surface 55 to strongly press the female taper 41 to the left, and as a reaction to this force, the first male thread 43 is pressed to the right against the female thread (no symbol) engraved on the valve body 10. This pressing force prevents the first male thread 43 from loosening and micromotion. [Industrial Applicability]

[0031] As described above, the valve of the present invention can provide a valve in which, when a high-temperature, high-pressure fluid is passed through, the seat member on which the valve seat is formed is unlikely to become loose, even if it is separate from the valve body. [Explanation of symbols]

[0032] 1 Valve 2 Actuators 3. Stem 4 Valve body 5. Bonnet 6 Fixing screws 7. York 10 Valve body 11 Inlet passage (fluid passage) 12 Outlet passage (fluid passage) 13 Valve chamber 14 Bottom 15 Valve chamber female thread 16 Sealing material 17 Opening 20, 40 Sheet material 21, 51 Male taper Aisles 22 and 42 23, 43 First male thread 24, 44 Valve seat contact surface 25, 55 Male taper abutment surface 26, 46 Flange part 27, 47 bottom surface 28, 48 Cutout surface 30, 50 Sheet material holder 31, 41 Female taper 32, 52 Through holes 33, 53 Second male thread 34, 45 Female taper abutment surface

Claims

1. a valve body having a fluid passage and a valve chamber on a bottom surface of the valve body that has an opening of the fluid passage; a seat member disposed in the valve chamber, the seat member including a passage communicating with the fluid passage, the seat member having a first male thread formed on an outer circumferential surface thereof and adapted to be screwed into the valve body; a valve body that comes into contact with and separates from the seat member; a seat member presser having an outer peripheral surface on which a second male screw is engraved and which screws into an inner peripheral surface of the valve chamber, the seat member presser having a through hole through which a stem having the valve body at its tip is inserted, and pressing the seat member; A valve comprising: One of the seat member and the seat member presser has a male taper protruding in the axial direction toward the other, and the other has a female taper mating with the male taper, A valve in which the central axis of the male taper and the central axis of the female taper are misaligned, and the male taper and the female taper are eccentrically mated.

2. 2. The valve according to claim 1, wherein the seat member has a flange portion facing the bottom surface, and a seal member is interposed between a lower surface of the flange portion and the bottom surface.

3. 3. The valve according to claim 2, wherein the seal member is a hollow metallic seal ring.

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