Ball valve

Abstract

To provide a ball valve which can suppress an external leakage of fluid in an extremely low temperature even with a ball valve using a seal member including a metal elastics body therein.SOLUTION: The ball valve includes: a valve body 2 having a fluid inlet passage 20, a fluid outlet passage 21, and an operation hole 3 formed in a direction perpendicular to the passages; a rotor 5 having a fluid communication passage 5a and rotationally provided inside the valve body 2; an operation mechanism for rotating the rotor 5; and a seal member 7 provided on a peripheral edge of a stem 6 connecting the operation mechanism and the rotor 5 and including a metal elastic body therein. The operation hole 3 is composed of a large diameter part 30 for permitting the seal member 7 to pass through on the operation mechanism side, and a small diameter part 31 that matches a diameter of the stem 6 on the rotor 5 side. A contact peripheral face of the seal member 7 of the large diameter part 30 is a tapered face 30a having a diameter tapering toward the rotor 5 side.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a ball valve for controlling the flow of a fluid, and particularly to a ball valve for controlling the flow of cryogenic liquid hydrogen.

Background Art

[0002] Liquid hydrogen used in hydrogen stations and the like is for use in FCVs (fuel cell vehicles). Since it is at an extremely low temperature and under an extremely high pressure, needle valves for high-pressure use exceeding 50 MPa or 90 MPa are widely used.

[0003] On the other hand, although the liquid hydrogen used for a hydrogen engine is at an extremely low temperature (-253°C), the operating pressure is, for example, a low pressure of about 0.2 to 0.3 MPa. Therefore, by adopting a cryogenic specification, a ball valve or the like can be used as the valve for use in the line through which liquid hydrogen flows.

[0004] At a substantially central portion of a valve body provided with a fluid flow path, it engages with an engaging portion at the tip of a stem inserted into the valve body, and the flow of the fluid flowing through the fluid flow path is communicated and blocked by a rotating body (ball valve body) that rotates approximately 90° along with the rotation of the stem.

[0005] As shown in FIG. 4, the ball valve 9 developed by the present inventors includes a body main body 2A having an operation hole 3 formed by a through hole 4 in which a rotating body 5 (ball valve body) is disposed, a large-diameter portion 30 and a small-diameter portion 31 communicating with the through hole 4, a side body 2B (flange) that sandwiches the body main body 2A and is fixed to the body main body 2A by a fastening member 8, and a stem 6 having an engaging portion 60 formed at the tip that engages with a groove portion 5b formed at the top of the rotating body 5. The rear end portion of the stem 6 is an operation mechanism joint portion 61 and is joined to an operation mechanism composed of an actuator such as a manual handle or an electric motor (not shown).

[0006] The rotating body 5 forms a fluid communication passage 5a inside that communicates with the fluid passage 20 formed in the side body 2B, and is held in the through hole 4 by a pair of seat rings 50. The fluid flowing through such a ball valve 9 leaks to the stem 6 side because the rotating body 5 rotates and slides between the rotating body 5 and the seat ring 50 that supports it, and the seal member 7 disposed in the large-diameter portion 30 of the operation hole 3 suppresses leakage to the outside.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] This seal member 7 uses a resin material that can withstand use at low temperatures, such as PTFE resin (tetrafluoroethylene resin), and further forms an annular groove portion and encloses a metal elastic body such as a spring therein to improve the sealing performance. However, when used at extremely low temperatures, the resin shrinks in the state at the time of attachment (room temperature) (see Fig. 4(a)) to the state at the time of use (extremely low temperature) (see Fig. 4(b)), and the outer peripheral surface of the seal member 7 and the inner peripheral surface of the large-diameter portion decrease from surface contact to about annular line contact, and there is a problem that sufficient sealing performance cannot be ensured even with the elastic force of the enclosed metal elastic body.

[0009] The present invention has been made in view of such points, and provides a ball valve that can suppress external leakage of fluid even at extremely low temperatures, even a ball valve using a seal member that encloses a metal elastic body inside.

Means for Solving the Problems

[0010] The ball valve according to the first invention made to solve the above problems is A valve body having a fluid inlet passage, a fluid outlet passage, and an operation hole formed in a direction perpendicular to these passages, A rotating body having a fluid communication passage and rotatably disposed within the valve body, An operating mechanism for rotating the rotating body, A ball valve comprising a seal member disposed at the periphery of a stem that connects the operating mechanism and the rotating body and enclosing a metal elastic body therein, The operation hole consists of a large-diameter portion that allows the passage of the seal member on the operating mechanism side and a small-diameter portion that matches the diameter of the stem on the rotating body side. The contact peripheral surface of the seal member of the large-diameter portion is a tapered surface that tapers toward the rotating body side.

[0011] Also, a ball valve according to the second invention made to solve the above problems, A valve body having a fluid inlet passage, a fluid outlet passage, and an operation hole formed in a direction perpendicular to these passages, A rotating body having a fluid communication passage and rotatably disposed within the valve body, An operating mechanism for rotating the rotating body, A ball valve comprising a seal member disposed at the periphery of a stem that connects the operating mechanism and the rotating body and enclosing a metal elastic body therein, The operation hole consists of a large-diameter portion that allows the passage of the seal member on the opening side and a small-diameter portion that matches the diameter of the stem on the rotating portion side. The contact peripheral surface of the seal member of the large-diameter portion is a middle-diameter portion that is smaller than the large-diameter portion and larger than the small-diameter portion.

[0012] According to the present invention, by making the large-diameter portion of the operation hole with which the seal member abuts a tapered surface that tapers the diameter or a middle-diameter portion that is smaller than the large-diameter portion, the seal member is compressed at normal temperature, and even when the resin shrinks in an extremely low temperature state, sufficient sealing performance can be ensured by the elastic force of the enclosed metal elastic body, and leakage of fluid to the outside can be suppressed.

[0013] In this case, the valve body can be composed of a body main body that forms a through hole for accommodating the rotating body and the operation hole, and a flange portion that sandwiches the body main body. Thereby, the incorporation and assembly of each part are simplified.

[0014] Further, the valve of the present invention can limit the use fluid to liquid hydrogen. This ball valve can surely block the external leakage of liquid hydrogen as a valve that conducts and shuts off the flow of liquid hydrogen with a boiling point of -253°C.

Effect of the Invention

[0015] According to the valve of the present invention, even in an extremely low temperature state or at room temperature, a resin seal member that encapsulates a metal elastic body inside and is attached by compression more than usual ensures sufficient sealing performance, and a ball valve that effectively suppresses the leakage of the internal fluid to the outside can be provided.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiment for Carrying Out the Invention

[0017] Hereinafter, a preferred embodiment of the valve according to the present invention will be described with reference to the drawings. The shape of the components described in this embodiment, their relative arrangement, etc. are not intended to limit the scope of the present invention as long as there is no specific description, and are merely illustrative examples. Also, for convenience, the directions of members etc. may be referred to as up, down, left, and right according to the directions on the drawings, but these do not limit the scope of the present invention.

[0018] <Embodiment 1> An embodiment of the first invention is shown. FIG. 1 is a front cross-sectional view of a partially cut-away valve 1 of the present invention. The ball valve 1 of the first invention has a valve body 2 having a fluid inlet passage 20, a fluid outlet passage 21, and an operation hole 3 formed in a direction perpendicular to these passages, a rotating body 5 having a fluid communication passage 5a and rotatably disposed in the valve body 2, an operation mechanism for rotating the rotating body 5, and a seal member 7 disposed on the periphery of a stem 6 connecting the operation mechanism and the rotating body 5 and enclosing a metal elastic body inside.

[0019] The operation hole 3 consists of a large-diameter portion 30 that allows the operation mechanism side to pass through the seal member 7 and a small-diameter portion 31 on the rotating body 5 side that matches the diameter of the stem 6. The contact peripheral surface of the seal member 7 of the large-diameter portion 30 is a tapered surface 30a that tapers toward the rotating body 5 side.

[0020] The configuration of the valve body 2 is not particularly limited, but it is composed of a through-hole 4 that houses the ball valve body that is the rotating body 5 and a body main body 2A that forms the operation hole 3, and side bodies 2B that sandwich the body main body 2A. The side bodies 2B form flange portions that connect to the upstream and downstream pipes, and form a fluid inlet passage 20 on one side and a fluid outlet passage 21 on the other side. The body main body 2A and the side bodies 2B are fixed by a fastening member 8, and a seal material 22 for cryogenic use is disposed on their mating surfaces to prevent leakage of fluid to the outside.

[0021] In the through hole 4 of the valve body 2A, in the same manner as in the prior art, a rotating body 5 is sandwiched between seat rings 50, 50 that form a pair, and is arranged such that a groove 5b that engages with an engaging portion 60 formed at the tip of the stem 6 comes to the top. A fluid communication passage 5a that penetrates the rotating body 5 is formed. The illustrated example shows a state where the fluid inlet passage 20 and the fluid outlet passage 21 are in communication, and the flow path is blocked by rotating the stem 6 by 90°.

[0022] Further, the fluid communication passage 5a of the rotating body 5 is formed in a T shape, the fluid communication passage 5a is opened to the facing side of the groove 5b, and a three-way valve can also be formed by forming a flow path and a flange on the lower side of the illustrated body main body 2A.

[0023] A seal member 7 that encloses a metal elastic body inside is disposed in the large-diameter portion 30 of the operation hole 3 of the valve body 2A. The seal member 7 has an inner diameter that is substantially the same as the outer diameter of the corresponding portion of the stem 6, and an outer diameter that is substantially the same as the inner diameter of the large-diameter portion 30. The seal member 7 is fixed by a seal retainer 70 that fixes it to the opening side of the operation hole 3 of the body main body 2A and restricts its movement in the vertical direction. The illustrated example shows an example in which two seal members 7 are attached, but it is not limited to this, and a seal member composite in which a seal material for cryogenic temperatures is attached to the inner diameter side and the outer diameter side can also be disposed on the seal member 7.

[0024] Also, an annular elastic member, for example, a coil wave spring or the like, can be disposed between the seal member 7 and the seal retainer 70 for the purpose of compensating for the decrease in surface pressure on the peripheral surface of the seal member 7 at cryogenic temperatures.

[0025] As shown in FIG. 2, the ball valve of the first invention having the above configuration is such that in the state at the time of attachment (room temperature) (see FIG. 2(a)), the seal portion is compressed by the tapered surface 30a, and even when it contracts in the state at the time of use (cryogenic temperature) (see FIG. 2(b)), the contact between the outer peripheral surface of the seal member 7 and the inner peripheral surface of the large-diameter portion maintains surface contact, and leakage of fluid to the outside can be suppressed.

[0026] <Embodiment 2> An embodiment of the second invention is shown. The ball valve 1 of the second invention includes a valve body 2 having a fluid inlet passage 20, a fluid outlet passage 21, and an operation hole 3 formed in a direction perpendicular to these passages, a rotating body 5 having a fluid communication passage 5a and rotatably disposed in the valve body 2, an operation mechanism for rotating the rotating body 5, and a seal member 7 disposed on the periphery of a stem 6 that connects the operation mechanism and the rotating body 5 and encloses a metal elastic body inside, which is the same as the first invention.

[0027] The operation hole 3 is composed of a large-diameter portion 30 that allows the operation mechanism side to pass through the seal member 7 and a small-diameter portion 31 on the rotating body 5 side that matches the diameter of the stem 6. The contact peripheral surface of the seal member 7 of the large-diameter portion 30 is a medium-diameter portion 30b that is smaller than the large-diameter portion 30 and larger than the small-diameter portion 31.

[0028] Thus, also in the ball valve 1 of the second invention, as shown in FIG. 3, in the state at the time of attachment (room temperature) (see FIG. 3(a)), the seal portion is compressed by the medium-diameter portion 30b, and even when it contracts in the state at the time of use (extremely low temperature) (see FIG. 3(b)), the contact between the outer peripheral surface of the seal member 7 and the inner peripheral surface of the large-diameter portion maintains surface contact, and leakage of the fluid to the outside can be suppressed.

Industrial Applicability

[0029] The valve according to the present invention can be suitably used as a valve that does not leak internal fluid to the outside even in an extremely low temperature state, and can be particularly suitably used as an on-off valve for a fluid having a boiling point of -253°C such as liquid hydrogen.

Explanation of Reference Numerals

[0030] 1 Ball valve 2 Valve body 2A Body main body 2B Side body (flange) 20 Fluid inlet passage 20 Fluid outlet passage 3 Operation hole 30 Large-diameter portion 30a Tapered surface Medium diameter part of 30b Small diameter part of 31 Through hole of 4 Rotating body (ball valve body) of 5 Seat ring of 50 Stem of 6 Engaging part of 60 Operating mechanism engaging part of 61 Sealing member of 7 Fastening member of 8

Claims

1. A valve body having a fluid inlet passage, a fluid outlet passage, and an operation hole formed in a direction perpendicular to these passages, a rotating body having a fluid communication passage and rotatably disposed within the valve body, an operation mechanism for rotating the rotating body, a ball valve comprising a seal member disposed at the periphery of a stem connecting the operation mechanism and the rotating body and enclosing a metallic elastic body therein, wherein the operation hole consists of a large-diameter portion allowing the passage of the seal member on the operation mechanism side and a small-diameter portion adapted to the diameter of the stem on the rotating body side, and the contact peripheral surface of the seal member of the large-diameter portion is a tapered surface that tapers in diameter toward the rotating body side.

2. A valve body having a fluid inlet passage, a fluid outlet passage, and an operation hole formed in a direction perpendicular to these passages, a rotating body having a fluid communication passage and rotatably disposed within the valve body, an operation mechanism for rotating the rotating body, a ball valve comprising a seal member disposed at the periphery of a stem connecting the operation mechanism and the rotating body and enclosing a metallic elastic body therein, wherein the operation hole consists of a large-diameter portion allowing the passage of the seal member on the opening side and a small-diameter portion adapted to the diameter of the stem on the rotating portion side, and the contact peripheral surface of the seal member of the large-diameter portion is a middle-diameter portion having a diameter smaller than the large-diameter portion and larger than the small-diameter portion.

3. The ball valve according to claim 1 or claim 2, wherein the valve body is composed of a body main body forming a through hole for housing the rotating body and the operation hole, and a pair of flange portions sandwiching the body main body.

4. The ball valve according to claim 1 or claim 2, wherein the fluid in use is liquid hydrogen.

Images