JP5855504B2 - Gate valve - Google Patents

Description

  The present invention is a kind of fluid control valve that controls the flow of fluid by causing a valve body to abut against or separate from each of two valve seats facing each other in a flow path formed in a straight line. It relates to a gate valve. Specifically, the two valve bodies are simultaneously pressed between the two valve seats by the valve stem wedge portion that is interlocked with the movement of the valve stem that is arranged in a direction orthogonal to the flow path. The present invention relates to a gate valve that is brought into contact with a seat to be closed.

  In a linear flow path, two valve stem wedges interlocking with the movement of the valve stem arranged in a direction orthogonal to the flow path between two valve seats formed at opposing positions, As a gate valve that simultaneously presses the valve bodies and closes them by contacting the valve seats, there is, for example, a gate valve disclosed in a catalog of non-patent literature. FIG. 9 is an explanatory view showing the gate valve disclosed in the non-patent document, and FIG. 10 is an exploded perspective view showing components constituting the Y portion in FIG. 9. As shown in FIGS. 9 and 10, the gate valve 101 of the non-patent document includes a first valve seat 114 and a second valve seat 115 formed in the body 110, and a stem 120 inserted through the through hole of the bonnet 161. A wedge portion 123 connected to the tip of the stem 120, a first valve body 130 that contacts or separates from the first valve seat 114, a second valve body 140 that contacts or separates from the second valve seat 115, The first pressing member 135 and the second pressing member 145 are provided. The first pressing member 135 has a first wedge contact surface 135a that is substantially parallel to the one side tapered surface 123a of the wedge portion 123, and the second pressing member 145 is substantially the same as the other side tapered surface 123b of the wedge portion 123. It has the parallel 2nd wedge part contact surface 145a.

  The gate valve 101 of non-patent literature opens and closes the valve by moving the stem 120 in the vertical direction. The gate valve 101 closes and is pressed by moving the wedge portion 123 at the tip of the stem 120 downward and pressing the wedge portion 123 against the first pressing member 135 and the second pressing member 145 at the same time. The first valve body 130 is brought into contact with the first valve seat 114 via the first pressing member 135. Further, the second valve body 140 is brought into contact with the second valve seat 115 via the second pressing member 145 pressed together with the first pressing member 135.

  In the gate valve 101 of the non-patent document, the vertical downward pressing force F acting on the wedge portion 123 causes the one-side tapered surface 123a of the wedge portion 123 to contact the first wedge portion abutting surface 135a of the first pressing member 135. By sliding in the state of surface contact, it is divided into a lower component force acting downward in the vertical direction and a one component force Fa acting on one side (left side in FIG. 9) in the flow path direction. The first valve body 130 moves toward the first valve seat 114 and closes by being pressed by the one side component Fa acting on the first pressing member 135.

  At the same time, a vertically downward pressing force F acting on the wedge portion 123 causes the other side tapered surface 123b of the wedge portion 123 to come into surface contact with the second wedge portion abutting surface 145a of the second pressing member 145. Is divided into a lower component force acting in the vertical direction and a second component force Fb acting on the other side in the flow path direction (right side in FIG. 9). The second valve body 140 moves toward the second valve seat 115 and closes by being pressed by the other side component force Fb acting on the second pressing member 145.

  In addition, in the gate valve of the non-patent document, the constituent members and parts are arranged symmetrically on both sides of the one side and the other side sandwiching the wedge part, and both sides are substantially the same. For reasons of space, the description includes that the one side taper surface and the other side taper surface of the wedge portion are “taper surfaces”, the first press member and the second press member are “press members”, There is also a portion in which the one valve body and the second valve body are collectively referred to as “valve body” and the first valve seat and the second valve seat are collectively referred to as “valve seat”.

Catalog of product name “Springless Parallel Slide Valve 400H SERIES” (manufactured by Nippon Koso Co., Ltd.)

  However, the prior art such as the gate valve of the non-patent literature has the following problems. In the gate valve of the non-patent document, the one side taper surface 123a of the wedge portion 123 is brought into surface contact with the first wedge portion abutting surface 135a of the first pressing member 135, and at the same time, the other side taper surface 123b of the wedge portion 123 is set to the first. 2 Since the structure is in surface contact with the second wedge portion contact surface 145a of the pressing member 145, due to the assembly accuracy at the time of manufacturing the gate valve, the magnitude and direction of the one-side component force Fa, The magnitude and direction of the other side component force Fb may be different on the left and right sides sandwiching the wedge portion 123. Moreover, when the opening / closing operation of the gate valve of the non-patent document is repeatedly performed, the portion that comes into contact with the surface and slides is unevenly worn over time, and between the one side component force Fa and the other side component force Fb, There may be differences in the magnitude and direction of the force. In the gate valve of the non-patent document, the one side tapered surface 123a of the wedge portion 123 is brought into surface contact with the first wedge portion abutting surface 135a of the first pressing member 135 and at the same time, the other side tapered surface 123b of the wedge portion 123 is used. Is in surface contact with the second wedge contact surface 145a of the second pressing member 145, and therefore, the cutoff performance varies due to contact resistance and wear at the surface contact portion.

  In addition, the gate valve of the non-patent document has a surface contact state between the one side tapered surface 123a of the wedge portion 123 and the first wedge portion abutting surface 135a of the first pressing member 135 and the other side of the wedge portion 123 at the time of manufacture. The surface contact state between the side taper surface 123b and the second wedge portion abutment surface 145a of the second pressing member 145 is set so that the one side component force Fa and the other side component force Fb act on the flow path axis AX. Is set. However, if the valve opening / closing operation is repeated, the taper surface of the wedge portion and the wedge contact surface of the pressing member are in surface contact with each other and wear and slide over time. The pressing force F from the stem 120 is transmitted to the wedge portion 123 at a position further lowered in the vertical direction from the set position. Therefore, the position where the pressing force F transmitted from the stem 120 acts in a distributed manner on the one side component force Fa and the other side component force Fb is lowered from the axis AX of the flow path. When the one-side component force Fa acts at a position lowered from the flow path axis AX, the first valve body 130 is partially biased and abutted on the lower side of the first valve seat 114 with the axis AX as a boundary. On the upper side of the one valve seat 114, the first valve body 130 cannot be contacted until the valve can be closed with a sufficient sealing force, and the contact state of the first valve body 130 is different between the upper and lower sides of the first valve seat 114. Similar to the one-side component force Fa, when the other-side component force Fb acts at a position lowered from the flow path axis AX, the second valve body 140 is below the second valve seat 115 with the flow path axis AX as a boundary. The second valve seat 115 cannot be brought into contact with a state where it can be closed with a sufficient sealing force on the upper side of the second valve seat 115, and the second valve body 140 is located on both upper and lower sides of the second valve seat 115. The contact state is different.

  Thus, if the magnitude of the one side component (or the other side component force) and the direction of the one side component force (or the other side component force) differ between the left and right sides sandwiching the wedge portion, The valve seats cannot be contacted evenly on the left and right sides, and the valve seats on both the left and right sides cannot be closed with a uniform sealing force. In addition, if the operating position of one side component force (or the other side component force) falls below the axis of the flow path while repeatedly opening and closing the valve, the valve element and the valve seat are in contact with each other. However, it is different on both the upper and lower sides with the axis of the flow path as a boundary, and each valve body cannot contact the respective valve seats evenly in the vertical direction, and the valve seats on both the left and right sides cannot be closed with a uniform sealing force. Therefore, if the contact state between the valve body and the valve seat is not even on both the left and right sides of the wedge part and on both the upper and lower sides with the axis of the flow path as a boundary, the fluid flow can be controlled with high accuracy. I can't. That is, as in the gate valve of the non-patent document, if the tapered surface of the wedge portion and the wedge contact surface of the pressing member slide in surface contact, the tapered surface of the wedge portion and the pressing member Since the sliding portion of the wedge contact surface comes into contact with the surface and wears over time, it becomes difficult to use the gate valve for a long period of time, and maintenance for replacing or repairing the worn portion at an early stage is difficult. Needed more often.

  On the other hand, when using the gate valve such as the gate valve of the non-patent document for a while until the maintenance is performed, the worker presses the valve body against the valve seat, that is, one side component force (or The other side component force) is gradually increased from the beginning of use, and the valve body is brought into close contact with the valve seat to prevent fluid leakage. In particular, in a gate valve such as a gate valve in non-patent literature, in order to adjust the pressing force applied to the wedge portion, a manual gate valve in which a handle connected to the stem is rotated and adjusted manually by an operator is used. The operator increases the rotation angle of the handle that rotates in the forward direction during the valve closing operation from the beginning of use, increases the pressing force applied to the wedge portion, and increases the one side component force (or the other side component force). ing. At this time, when the pressing force is insufficient and the valve body is not in close contact with the valve seat, the operator temporarily rotates the handle in the reverse direction to return to the position where the valve is opened, and then from the valve opened state. Since this operation is repeated until the handle is rotated in the forward direction again and the pressing force capable of closing the valve can be transmitted to the valve body, the burden on the operator is large. In addition, when the tapered surface of the wedge portion and the wedge contact surface of the pressing member are configured to slide in surface contact, the frictional force between the taper surface and the wedge contact surface acts greatly. Therefore, when an operation for increasing the pressing force applied to the wedge portion is performed, a burden imposed on the operator increases. When the above-mentioned wear has grown excessively, the valve body can be brought into contact with the valve seat in a stable state so that no fluid leaks no matter how much the pressing force applied to the wedge portion is increased. It becomes impossible and the fluid leaks from between the valve body and the valve seat. If fluid leakage occurs between the valve body and the valve seat, the gate valve needs to be disassembled.

  The present invention has been made to solve the above-described problems, and includes a first valve seat and a second valve seat arranged at positions facing each other across a valve rod wedge portion in a linear flow path. On the other hand, in a gate valve that closes the first valve body and the second valve body by simultaneously pressing them with the pressing force from the valve stem transmitted to the two tapered surfaces of the valve stem wedge portion of the valve stem tip, An object of the present invention is to provide a gate valve that can be closed with a stable sealing force even when the opening / closing operation is repeatedly performed a plurality of times.

  In order to solve the above problems, the gate valve of the present invention has the following configuration.

(1) The first valve body, the second valve body, the input port and the output port are formed on the input port side with respect to the intermediate flow path, the body formed on the first axis across the intermediate flow path The first valve seat, the second valve seat formed on the output port side with respect to the intermediate flow path, the first tapered surface and the second tapered surface are formed in a wedge shape, and the first axial direction along the first axis A valve stem wedge portion connected to a valve stem movable in a second axis direction perpendicular to the valve stem, and the valve stem wedge portion that is interlocked with the movement of the valve stem includes the first valve body and the second valve By simultaneously moving the body to the opposite sides with respect to the first axis direction, the first valve body and the second valve body against the first valve seat and In the gate valve that controls the flow of the fluid flowing through the intermediate flow path by contacting or separating, the first valve body has a first axial direction relative to the first axial direction. On the opposite side of the first abutment surface that abuts the seat, a first protrusion is formed that projects to form a first apex, and the second valve body is located on the second valve seat with respect to the first axial direction. On the opposite side of the second abutting surface that abuts, there is a second projection that forms a second apex and projects, and at the same time the first projection slides in contact with the first taper surface, When the two protrusions slide in contact with the second taper surface, the first valve body contacts the first valve seat and the second valve body contacts the second valve seat to close the valve. It is characterized by that.
(2) In the gate valve described in (1), both the first protrusion and the second protrusion are formed in a hemispherical shape.
(3) In the gate valve described in (1) or (2), the first valve body has a plate-like first base portion having a first contact surface, which is separate from the first protrusion, The first protrusion is detachably attached to the first base, and the second valve body has a plate-like second base that is separate from the second protrusion and has a second contact surface; The second protrusion is detachably attached to the second base.
(4) The gate valve described in (3) is characterized in that at least the first base and the second base are made of resin.

  The operation and effect of the gate valve of the present invention having the above configuration will be described.

(1) The first valve body, the second valve body, the input port and the output port are formed on the input port side with respect to the intermediate flow path, the body formed on the first axis across the intermediate flow path The first valve seat, the second valve seat formed on the output port side with respect to the intermediate flow path, the first tapered surface and the second tapered surface are formed in a wedge shape, and the first axial direction along the first axis A valve stem wedge portion connected to a valve stem movable in a second axis direction perpendicular to the valve stem, and the valve stem wedge portion that is interlocked with the movement of the valve stem includes the first valve body and the second valve By simultaneously moving the body to the opposite sides with respect to the first axis direction, the first valve body and the second valve body against the first valve seat and In the gate valve that controls the flow of the fluid flowing through the intermediate flow path by contacting or separating, the first valve body has a first axial direction relative to the first axial direction. On the opposite side of the first abutment surface that abuts the seat, a first protrusion is formed that projects to form a first apex, and the second valve body is located on the second valve seat with respect to the first axial direction. On the opposite side of the second abutting surface that abuts, there is a second projection that forms a second apex and projects, and at the same time the first projection slides in contact with the first taper surface, When the two protrusions slide in contact with the second taper surface, the first valve body contacts the first valve seat and the second valve body contacts the second valve seat to close the valve. In order to close the valve by bringing the first valve body into contact with the first valve seat and the second valve body into contact with the second valve seat, the valve stem on one side in the second axial direction is The pressing force is transmitted to the valve stem wedge part, and is divided into an input port side component force acting on the input port side and an output port side component force acting on the output port side in the first axial direction. That. At this time, the vicinity of the first top portion of the first protrusion and the first tapered surface of the valve stem wedge portion, and the vicinity of the second top portion of the second protrusion portion and the second tapered surface of the valve stem wedge portion are slid. When moving, the first protrusion side and the second protrusion side are in contact with each other in a substantially point contact state.

  That is, in the gate valve of the present invention, the point contact position between the vicinity of the first top of the first protrusion and the first tapered surface of the valve stem wedge, and the vicinity of the second top of the second protrusion and the valve stem wedge. When the point contact position with the second taper surface is located on the first axis of the intermediate flow path, the first valve body is pressed by the input port side component force and comes into contact with the first valve seat to close the valve. Let At this time, the contact portion between the first valve body and the first valve seat in the radial direction centered on the first axis is the contact surface of the first valve seat centered on the first axis (the first valve body is The contact portions are uniform over the entire circumference in the circumferential direction of the contact surface, and the sealing force of the first valve body that contacts the first valve seat can be obtained in a stable state. At the same time as the first valve body is pressed and the first valve seat is closed, the second valve body is pressed and brought into contact with the second valve seat and closed by the output port side component force. At this time, the contact portion between the second valve body and the second valve seat in the radial direction centered on the first axis is the contact surface of the second valve seat centered on the first axis (the second valve body is The sealing force of the second valve element that is uniform over the entire circumference of the abutting surface) and that abuts the second valve seat can be obtained in a stable state. Further, the point contact position between the vicinity of the first top of the first protrusion and the first tapered surface of the valve stem wedge portion, and the vicinity of the second top of the second protrusion and the second tapered surface of the valve stem wedge portion The point contact position is a balanced position on both the left and right sides of the valve stem wedge. Therefore, a difference in sealing force is unlikely to occur between the sealing force of the first valve body that contacts the first valve seat and the sealing force of the second valve body that contacts the second valve seat. Further, due to the assembly accuracy at the time of manufacture of the gate valve, the seal between the sealing force of the first valve body that contacts the first valve seat and the sealing force of the second valve body that contacts the second valve seat Differences in power are unlikely to occur.

  In particular, the point contact position between the vicinity of the first top of the first protrusion and the first tapered surface of the valve stem wedge portion, and the vicinity of the second top of the second protrusion and the second tapered surface of the valve stem wedge portion. If the point contact position is located on the first axis of the intermediate flow path, the first protrusion is disposed at the center of the first valve body, and the second protrusion is disposed at the center of the second valve body, The direction of the input port side component force and the direction of the output port side component force are maintained in a straight direction along the first axis direction even when the gate valve is used for a long period of time. Therefore, the sealing force of the first valve body that abuts on the first valve seat and the sealing force of the second valve body that abuts on the second valve seat are on both the upper and lower sides with the first axis as a boundary. By acting equally on the entire circumferential direction and the entire circumferential direction of the second valve seat, it is possible to maintain a stable state while suppressing a decrease over time. In addition, the vicinity of the first top of the first protrusion and the first taper surface of the valve stem wedge portion, and the vicinity of the second top of the second protrusion and the second taper surface of the valve stem wedge portion are almost all. Since the contact is point contact, uneven wear is less likely to occur compared to a conventional gate valve in which the tapered surfaces on both sides of the wedge portion are brought into surface contact with the wedge contact surface of each pressing member. Therefore, even if the opening / closing operation of the valve is repeated a plurality of times, the first valve body and the second valve body abut against the first valve seat and the second valve seat in a uniform state so that fluid leakage does not occur. Thus, it is possible to maintain the valve closing with a small force and a high adhesion force for a longer period. In particular, even when the fluid to be controlled is a flammable fluid such as LNG having a cryogenic temperature of 162 ° C. below zero, the valve can be kept closed with high adhesion so as not to leak.

  Further, the vicinity of the first top of the first protrusion and the first tapered surface, and the vicinity of the second top of the second protrusion and the second tapered surface are both substantially point contact, and the second axis. The pressing force of the valve rod applied to one side in the direction is from the center of the first valve body to the first valve seat via the first protrusion, and from the center of the second valve body to the second valve via the second protrusion. Each is transmitted directly to the seat. Therefore, the relative wear between the vicinity of the first top of the first protrusion and the first tapered surface, and the relative wear between the vicinity of the second top of the second protrusion and the second tapered surface are determined by the wedge portion. This can be suppressed as compared with a conventional gate valve in which each taper surface and each wedge contact surface of the pressing member are brought into surface contact and slid. Therefore, the number of maintenance operations for exchanging or repairing a worn portion or the like can be reduced, and the cost can be reduced. Further, even if the valve opening / closing valve operation is repeated a plurality of times, the valve stem wedge portion, the first projection portion of the first valve body, and the second projection portion of the second valve body are not easily worn. The wear powder hardly mixes in the fluid flowing in the flow path.

  Therefore, the gate valve of the present invention has an excellent effect that the valve can be closed with a stable sealing force even when the opening and closing operation of the valve is repeated a plurality of times.

(2) In the gate valve described in (1), since both the first protrusion and the second protrusion are formed in a hemispherical shape, the pressing force to the valve stem is When the first valve body is pushed by the input port side component acting on the first taper surface of the valve stem wedge portion and moves to the input port side when the first valve body is moved to the input port side, Is moved on the first taper surface of the valve stem wedge portion. At the same time, when the second valve body is pressed by the output port side component acting on the second taper surface of the valve stem wedge portion and moves to the output port side, the contact portion with the second protrusion of the hemispherical shape is It moves on the second taper surface of the valve stem wedge. Thereby, the valve stem wedge portion does not wear at the same portion of the first tapered surface and at the same portion of the second tapered surface. Further, when both the first protrusion and the second protrusion are formed in a hemispherical shape, the contact state between the first protrusion and the vicinity of the first top of the first protrusion with respect to the first tapered surface of the valve stem wedge ( The contact surface, angle, etc.) hardly change over time. In addition, the contact state (contact surface, angle, etc.) of the second protrusion with the second taper surface of the valve stem wedge portion hardly changes over time.

  Therefore, the direction of the input port side component force and the direction of the output port side component force are maintained in a straight direction along the first axial direction during the longer period of use of the gate valve, and the first valve seat The sealing force of the first valve body that abuts and the sealing force of the second valve body that abuts the second valve seat are prevented from decreasing over time, and can be maintained in a stable state. Accordingly, the first valve body is in contact with the first valve seat and the second valve body is in contact with each contact portion in a uniform state over the entire circumference, so that there is no fluid leakage. It is possible to maintain the contact and close with close contact force for a longer period.

  Also, wear between the first taper surface of the valve stem wedge portion and the vicinity of the first top of the first projection portion of the first valve body, and the second taper surface of the valve stem wedge portion and the second projection portion of the second valve body. The wear with the vicinity of the second top can be further reduced. Therefore, each of the gate valve according to the present invention and the conventional gate valve in which both the tapered surfaces of the wedge portion and the wedge contact surface of each pressing member are slid in surface contact with each other are pressed onto the valve rod. In the gate valve according to the present invention, when the pressures are applied at the same magnitude, the input port side component force required to bring the first valve body into contact with the first valve seat, and the second valve body are connected to the second valve seat. The component force on the output port side required to contact the valve body can be further reduced, and the loss of force transmitted from the pressing force to the valve stem to the first valve body and the second valve body can be reduced. Therefore, in order to close both the first valve body side and the second valve body side, the valve rod applied with the pressing force is moved to one side in the second axial direction, and one side in the second axial direction applied to the valve rod wedge portion. The pressing force can be made smaller than that of a conventional gate valve in which the tapered surfaces on both sides of the wedge portion and the wedge portion contact surface of each pressing member are brought into sliding contact with each other.

  In particular, even when the gate valve of the present invention has a structure in which, for example, a handle wheel connected to the valve stem is rotated manually by an operator to adjust the pressing force applied to the valve stem wedge portion, The direction of the component force on the port side and the direction of the component force on the output port side are easily acted while being maintained in a straight direction along the first axial direction. Therefore, when the operator rotates the handle wheel in one direction during the valve closing operation, the clamping force for closing the valve and shutting off the fluid is also reduced by the tapered surfaces on both sides of the wedge portion and the wedge portion contact surface of each pressing member. As compared with the conventional gate valve slid in contact with each other, it is possible to reduce the burden on the operator for the valve closing operation. When the gate valve of the present invention has a structure in which a screw is provided on the valve stem in order to convert the rotary motion of the handle wheel into the vertical motion of the valve stem, the gate valve of the present invention has the first valve body. Since the tightening force for shutting off the fluid by the second valve body can be reduced, the screw pitch for raising and lowering the valve stem can be increased, and the number of rotations of the handle wheel when the valve is opened and closed is This can be reduced compared to a conventional gate valve having the same structure.

  In the gate valve of the present invention, if both the first protrusion and the second protrusion are made of, for example, metal, the vicinity of the first top of the first protrusion and the first of the valve stem wedge The first taper surface and the vicinity of the second top portion of the second protrusion and the second taper surface of the valve stem wedge portion can be in contact with each other in a state close to point contact, so that the above-described wear is reduced. And preferably, a measure for giving wear resistance to the first protrusion and the second protrusion is taken.

(3) In the gate valve described in (1) or (2), the first valve body has a plate-like first base portion having a first contact surface, which is separate from the first protrusion, The first protrusion is detachably attached to the first base, and the second valve body has a plate-like second base that is separate from the second protrusion and has a second contact surface; Since the second protrusion is detachably attached to the second base portion, the first protrusion or the second taper surface between the first taper surface of the valve stem wedge portion and the second taper surface Even if the second projections are worn by receiving frictional force, the first base of the first valve body and the second base of the second valve body can be replaced by simply replacing the first projection and the second projection. The base can continue to be used. Also, when the first valve body is made of different materials for the first base and the first protrusion, or when the second valve body is made of different materials for the second base and the second protrusion. Such a 1st valve body and a 2nd valve body can be manufactured easily.

(4) Since the gate valve described in (3) is characterized in that at least the first base and the second base are formed of resin, the resin is more easily deformed than metal. The first abutment surface of the first base and the first valve seat can be in close contact with each other, and the sealing performance of the first valve body that abuts on the first valve seat can be largely ensured. In addition, the second contact surface of the second base portion and the second valve seat are easily in close contact with each other, and the sealing performance of the second valve body that contacts the second valve seat can be ensured greatly.

  In particular, when the fluid to be controlled is, for example, a fluid such as LNG at a cryogenic temperature of 162 ° C. below zero, the resin to be used needs to be made of a material that can withstand extremely low temperatures. In this case, for example, if the resin is a composite resin of poly ether ether ketone (PEEK) and carbon fiber (PEEK / carbon fiber composite resin), this type of resin is resistant to abrasion and compression. Since the mechanical properties such as strength are materials that can be maintained at the same level as room temperature even at an extremely low temperature of 162 ° C. below zero, the gate valve of the present invention controls the flow of such a cryogenic fluid. It can also be applied to cases. Further, even when the fluid to be controlled is a flammable fluid such as LNG having a cryogenic temperature of 162 ° C. below zero, the PEEK / carbon fiber composite resin is not altered by the contact of the flammable fluid.

It is explanatory drawing which shows the gate valve which concerns on embodiment, and shows a valve opening state. It is explanatory drawing which shows the gate valve which concerns on embodiment, and shows the intermediate state immediately after the 1st valve body and 2nd valve body which are descending contacting the body in the intermediate flow path. It is explanatory drawing which shows the gate valve which concerns on embodiment, and shows a valve closing state. It is a disassembled perspective view which shows the components which comprise X part in FIG. In FIG. 4, it is AA arrow sectional drawing. It is explanatory drawing which shows the 1st valve body and 2nd valve body which were comprised by the gate valve which concerns on embodiment, In FIG. 6, the left side is FIG. 4, the BB arrow sectional drawing, and the right side is FIG. It is CC sectional view taken on the line. It is a table | surface which shows the result of a performance evaluation test about the gate valve which concerns on embodiment. It is explanatory drawing which shows the 1st valve body and 2nd valve body which concern on a modification, In FIG. 6, the left side is the figure shown by the cross section corresponded to BB arrow in FIG. 4, The right side is FIG. It is the figure shown in the cross section equivalent to CC arrow. It is explanatory drawing which shows the gate valve which concerns on a nonpatent literature of a prior art. FIG. 10 is an exploded perspective view showing components constituting the Y part in FIG. 9.

  Hereinafter, embodiments of the gate valve according to the present invention will be described in detail with reference to the drawings. Drawing 1 is an explanatory view showing the gate valve concerning an embodiment, and shows a valve opening state. FIG. 3 is a diagram showing a closed valve state. In the present embodiment, in FIG. 1, the left-right direction is the first axial direction L1, and the second axial direction L2 orthogonal to the first axial direction L1 is the vertical direction. The drawings subsequent to FIG. 2 also follow the directions shown in FIG. Moreover, in FIG. 1 thru | or FIG. 3, in order to make a figure legible, the part relevant to a valve drive part is shown with a front view, and others are shown with sectional drawing.

  The gate valve 1 of the present embodiment is disposed in a facility that manufactures LNG (corresponding to the fluid of the present invention) having a cryogenic temperature of 162 ° C. below zero, and the LNG flowing from the primary side (input port 11 side) It is used for the purpose of controlling the flow to the (output port 12 side).

  First, the overall configuration of the gate valve 1 will be briefly described with reference to FIGS. 1 and 3. As shown in FIG. 1, the gate valve 1 includes a body 10, a valve stem 20, a valve stem wedge member 22 (corresponding to the valve stem wedge portion of the present invention), a first valve body 30, a second valve body 40, and a lid 61. , Handle 63, yoke support member 64, cover 65, yoke sleeve 68, and the like. The body 10 is made of metal, and in this embodiment, the body 10 is made of a stainless material containing a predetermined additive so that mechanical properties such as compressive strength can be maintained at the same level as room temperature even at an extremely low temperature of 162 ° C. below zero. . In the body 10, an input port 11 and an output port 12 are formed on the first axis AX across the intermediate flow path 13, and the first valve seat 14 is on the input port 11 side with respect to the intermediate flow path 13. The second valve seat 15 is formed on the output port 12 side with respect to the intermediate flow path 13. The body 10 and the lid 61 are fixed by bolting.

  The valve stem 20 is a round bar-like member extending in the second axial direction L2 perpendicular to the first axial direction L1 along the first axial line AX. The valve stem 20 is made of metal, and in the present embodiment, the mechanical property such as compressive strength is made of a stainless material containing a predetermined additive so that the mechanical properties such as compressive strength can be maintained at the same level as room temperature even at an extremely low temperature of 162 ° C below zero. Become. A male screw 29 is formed along the second axial direction L2 on one end (upper side in FIG. 1) of the valve stem 20 in the second axial direction L2. A yoke sleeve 68 is rotatable at one end of the valve stem 20 in the second axial direction L2 with respect to the valve stem 20 about its axis, and is provided with a yoke support member with respect to the second axial direction L2. 64 is arranged in a fixed state. A handle 63 for moving the valve stem 20 in the second axial direction L2 is attached to the yoke sleeve 68. As the handle 63 rotates, the yoke sleeve 68 also rotates. The yoke sleeve 68 is formed with a hole through which the end of the valve stem 20 can be inserted, and a female screw 69 that is screwed into the male screw 29 of the valve stem 20 is formed in this hole. In the gate valve 1 according to the present embodiment, when the operator manually rotates the handle 63, the yoke sleeve 68 rotates with the rotation of the handle 63, so that the male screw that engages with the female screw 69 of the yoke sleeve 68. 29 moves relative to the female screw 69 in the second axial direction L2, so that the valve stem 20 can move in the second axial direction L2.

  The valve stem 20 is inserted through the through-hole of the packing box 67 fixed together with the yoke support member 64, and even if it moves in the second axial direction L 2, the through-hole of the packing box 67 and the outer periphery of the valve stem 20 Are sealed hermetically by the packing 66A, the lantern ring 66B, and the packing 66C so that there is no leakage of LNG. Further, a valve rod lower end 21 is formed at the other end side (lower side in FIG. 1) of the valve rod 20 in the second axial direction L2. The valve stem lower end portion 21 has an upper diameter large portion 21A and a lower diameter large portion 21C that are larger than the diameter of the other portion of the valve rod 20, and the upper diameter large portion 21A and the lower diameter large portion 21C. The intermediate diameter small portion 21B is smaller than the upper large diameter portion 21A and the lower large diameter portion 21C. In the gate valve 1 according to the present embodiment, the upper diameter large portion 21A has a tapered shape whose tip is narrowed toward one end (upper side in FIG. 1), and is formed in an annular shape centering on the axis of the valve stem 20. A reverse seat 21Aa is formed. An intermediate portion of the valve stem 20 between the reverse seat 21Aa of the upper large diameter portion 21A and the packing box 67 is inserted into the lid insertion hole 62H of the lid 61, and the periphery of this intermediate portion is covered with a cover 65 or the like. It has been broken.

  Next, the valve body drive part illustrated in the X part in FIG. 1 will be described with reference to FIGS. FIG. 4 is an exploded perspective view showing components constituting part X in FIG. FIG. 5 is a cross-sectional view taken along line AA in FIG. 6 is an explanatory view showing a first valve body and a second valve body configured in the gate valve according to the embodiment. In FIG. 6, the left side is FIG. 4, and the right side is a cross-sectional view taken along the line BB. It is CC sectional view taken on the line in FIG. As shown in FIG. 4, the valve body drive unit includes a valve rod wedge member 22, a first valve body 30, a second valve body 40, and a valve body guide 50.

  First, the valve stem wedge member 22 will be described. The valve stem wedge member 22 is a member that is connected to the lower end portion 21 of the valve stem 20 and interlocks with the movement of the valve stem 20 in the second axial direction L2. In this embodiment, the valve stem wedge member 22 is made of metal such as stainless steel. As shown in FIG. 5, the valve stem wedge member 22 includes a wedge forming portion 22A and a valve stem connecting portion 22B connected integrally with the wedge forming portion 22A.

  The wedge forming portion 22A has a wedge 23 in which a first tapered surface 23a and a second tapered surface 23b are formed in a wedge shape. The first taper surface 23a and the second taper surface 23b have a shape constricted on the opposite side to the valve stem coupling portion 22B with respect to the second axial direction L2, and the first taper surface 23a and the second taper surface 23b In this embodiment, θ = 3 ° with respect to the second axial direction L2. In the wedge forming portion 22A, pin-like hook portions 24 and 24 projecting in a direction orthogonal to the second axial direction L2 are provided from the first tapered surface 23a and the second tapered surface 23b. The hooks 24, 24 may be formed integrally with the wedge 23, or may be inserted into the first tapered surface 23a and the second tapered surface 23b separately from the wedge 23, respectively.

  The valve stem connecting portion 22B includes a substantially disc-shaped wedge portion connecting portion 25A, and a substantially U-shaped valve stem lower end contact portion 25B disposed in parallel with and spaced from the wedge portion connecting portion 25A. ing. A notch 26 is formed inside the valve stem lower end contact portion 25 </ b> B so as to accommodate a small intermediate diameter portion 21 </ b> B of the valve stem lower end portion 21 of the valve stem 20. Between the wedge part connecting part 25A and the valve stem lower end contact part 25B is an engaging part 28 that can be engaged with the lower diameter large part 21C of the valve stem lower end part 21. The engaging portion 28 is a space surrounded by an inner peripheral surface 27 outside the inner peripheral surface in the radial direction (left and right direction in FIG. 5) of the notch 26, and communicates with the notch 26. The valve stem wedge member 22 accommodates the lower diameter large portion 21C of the valve stem lower end portion 21 in the engaging portion 28 of the valve rod connecting portion 22B, and the intermediate diameter small portion 21B inserted from the side through the notch 26 as the valve. The upper upper diameter portion 21A is fixedly connected to the valve stem 20 by covering it with the lower rod contact portion 25B and disposing the upper upper diameter portion 21A above the upper surface 25Ba of the reverse seat contact portion of the valve rod lower end contact portion 25B. The wedge forming portion 22A and the valve stem connecting portion 22B are connected by welding the wedge portion connecting portion 25A and the wedge 23 together.

  Next, the first valve body 30 will be described. The first valve body 30 is a valve body that contacts or separates from the first valve seat 14. The first valve body 30 is opposite to the flat first contact surface 31a in contact with the first valve seat 14 with respect to the first axial direction L1, and is opposite to the first contact surface 31a in parallel with the first contact surface 31a. It has a side surface 31b, and a hemispherical first protrusion 33 that protrudes by forming a first top 33T on the first opposite side surface 31b side.

  Specifically, in the present embodiment, the first valve body 30 has a plate-like first base portion 31 having a first contact surface 31a, which is separate from the first projection portion 33, and has a first projection. The part 33 is detachably attached to the first base 31. The first protrusion 33 is a flow path connecting the input port 11 and the intermediate flow path 13 when the first contact surface 31a of the first valve body 30 and the first valve seat 14 are closed. A position corresponding to the center in the radial direction, that is, on the first opposite side surface 31b side of the position corresponding to the radial center of the first contact surface 31a in the first valve body 30, is formed with a maximum outer diameter of about Φ5 mm. Are arranged.

  The first protrusion 33 has a first fixing portion 34 embedded in the first base 31. In the present embodiment, the first base portion 31 is formed of a composite material resin (PEEK / carbon fiber composite resin) of poly ether ether ketone (PEEK) and carbon fiber, and the first protrusion 33. Is made of a metal such as a stainless steel containing a predetermined additive so that the mechanical properties such as compressive strength can be maintained at the same level as room temperature even at an extremely low temperature of 162 ° C. below zero. In addition, the material of the 1st base part 31 is made to contain a predetermined additive so that mechanical properties such as compressive strength can be maintained at the same level as normal temperature even at an extremely low temperature of 162 ° C. It is also possible to use a metal such as stainless steel.

  The first base portion 31 is provided with a through hole 31H penetrating in the thickness direction TH along the first axial direction L1. Further, the first opposite side surface 31b of the first base portion 31 is provided with a first slit 35 in the valve stem wedge member 22 that can be engaged with the hook portion 24 of the wedge 23 of the wedge forming portion 22A. Furthermore, a first recess 32 for inserting the first fixing portion 34 and fixing the first protrusion 33 to the first base 31 is formed on the first opposite side surface 31 b.

  Next, the second valve body 40 will be described. The second valve body 40 is a valve body that contacts or separates from the second valve seat 15, and has the same shape as the first valve body 30 except for the through hole 31 </ b> H of the first base portion 31 of the first valve body 30. It is a size. The second valve body 40 is opposite to the flat second contact surface 41a contacting the second valve seat 15 with respect to the first axial direction L1, and is second opposite to the second contact surface 41a. A side surface 41b is provided, and a second protrusion 43 having a hemispherical shape is formed on the second opposite side surface 41b side to project and form a second top portion 43T.

  Specifically, in the present embodiment, the second valve body 40 has a plate-like second base 41 having a second contact surface 41a, which is a separate body from the second protrusion 43, and the second protrusion The portion 43 is detachably attached to the second base portion 41. The second protrusion 43 is a flow path connecting the output port 12 and the intermediate flow path 13 in a state where the second contact surface 41a of the second valve body 40 and the second valve seat 15 are in contact and closed. A position corresponding to the center in the radial direction, that is, on the second opposite side surface 41b side of the position corresponding to the central portion in the radial direction of the second contact surface 41a in the second valve body 40, is formed to have a maximum outer diameter of about Φ5 mm. Are arranged. That is, in the state assembled to the gate valve 1, the first top 33T of the first protrusion 33 and the second top 43T of the second protrusion 43 are disposed on the first axis AX.

  The second protrusion 43 has a second fixing portion 44 embedded in the second base 41. In the present embodiment, like the first base portion 31, the second base portion 41 is formed of a composite material resin (PEEK / carbon fiber composite resin) of poly ether ether ketone (PEEK) and carbon fiber. . The second protrusion 43 is made of a metal such as a stainless steel containing a predetermined additive so that mechanical properties such as compressive strength can be maintained at the same level as room temperature even at an extremely low temperature of 162 ° C. below zero. In addition, the material of the second base portion 41 contains a predetermined additive so that the mechanical properties such as compressive strength can be maintained at the same level as normal temperature even at an extremely low temperature of 162 ° C. It is also possible to use a metal such as stainless steel.

  In the second opposite side surface 41b of the second base portion 41, a second slit 45 that can engage with the hook portion 24 of the wedge 23 of the wedge forming portion 22A is recessed in the valve rod wedge member 22. The second opposite side surface 41 b is formed with a second recess 42 for inserting the second fixing portion 44 and fixing the second protrusion 43 to the second base portion 41.

  Next, the valve body guide 50 will be described. When the valve body guide 50 performs valve opening / closing operations simultaneously on both the input port 11 side and the output port 12 side, the first valve body 30, the second valve body 40, and the valve stem wedge member 22 are The member is slid in the axial direction L2. The valve body guide 50 is made of metal, and in this embodiment, a stainless material containing a predetermined additive so that mechanical properties such as compressive strength can be maintained at the same level as room temperature even at an extremely low temperature of 162 ° C. below zero. Consists of.

  As shown in FIGS. 1 to 4, the valve body guide 50 is formed with an opening 52 having a substantially rectangular cross section and penetrating in the second axial direction L2 in a circle which is a cross section of a cylinder. Yes. In the opening 52, guide slits 53, 53 that are recessed from the side surface of the short side are formed on both side surfaces of the short side that face each other. The groove width of the guide slits 53, 53 (size in the upper left-lower right direction in FIG. 4) is set to the size of the thickest portion of the wedge 23 of the wedge forming portion 22A (size in the left-right direction in FIG. 5). It has a corresponding uniform size, and both side portions of the valve stem wedge member 22 (ends on the left and right sides in FIG. 4) can move straight up and down in the guide slits 53 and 53. Yes. That is, the guide slits 53, 53 are the valve rod wedge members 22 sandwiched between the first valve body 30, the second valve body 40, and the first and second valve bodies 30, 40 during the opening / closing operation of the valve. Has a detent function for restricting rotation in the opening 52.

  The opening 52 has an opening first side surface 52a and an opening second side surface 52b, which are long side surfaces. The opening first side surface 52a contacts the first contact surface 31a of the first base 31 of the first valve body 30 in the state where the first valve body 30 is inserted into the opening 52, and the second axial direction L2 On the other hand, when the first valve body 30 or the like moves up and down, the first contact surface 31a slides on the opening first side surface 52a. In addition, the opening second side surface 52b contacts the second contact surface 41a of the second base 41 of the second valve body 40 in a state where the second valve body 40 is inserted into the opening 52, and the second axis line When the second valve body 30 or the like moves up and down with respect to the direction L2, the second contact surface 41a slides on the opening second side surface 52b.

  Next, the operation of the gate valve 1 will be described. In the gate valve 1, the valve stem wedge member 22 interlocked with the movement of the valve stem 20 with respect to the second axial direction L2 causes the first valve body 30 and the second valve body 40 to move with respect to the first axial direction L1. , Move to opposite sides at the same time. Thus, the first contact surface 31a of the first base 31 of the first valve body 30 with respect to the first valve seat 14 and the second base 41 of the second valve body 40 with respect to the second valve seat 15 are The two abutment surfaces 41a abut or separate at the same time, whereby the flow of LNG flowing through the intermediate flow path 13 is controlled. Further, in the gate valve 1, the first protrusion of the first valve body 30 until the first contact surface 31 a of the first base portion 31 of the first valve body 30 contacts the first valve seat 14 and closes. Of the portion 33, the vicinity of the first top portion 33 </ b> T mainly slides in a state where the wedge forming portion 22 </ b> A of the valve stem wedge member 22 is in contact with the first tapered surface 23 a of the wedge 23. At the same time, until the second contact surface 41a of the second base 41 of the second valve body 40 contacts the second valve seat 15 and closes, the second protrusion 43 of the second valve body 40 Of these, the vicinity of the second top portion 43 </ b> T mainly slides in the wedge forming portion 22 </ b> A of the valve rod wedge member 22 while being in contact with the second tapered surface 23 b of the wedge 23.

  This will be specifically described with reference to FIGS. 1 to 3 and FIG. When the gate valve 1 is in the open state, the valve stem 20 is in a predetermined upper position. At the lower end portion 21 of the valve stem, the reverse seat 21Aa of the upper diameter large portion 21A is inserted into the lid 61 as shown in FIG. It is in contact with the opening edge of the hole 62H, and prevents the LNG in the intermediate flow path 13 from leaking outside through the lid insertion hole 62H. In this state, the first valve body 30 and the second valve body 40 connect the hook portions 24 and 24 of the wedge 23, the first slit 35 of the first base 31 of the first valve body 30, and the second valve body. The upper side surface of the second slit 45 of the 40 second base 41 is lifted. In the valve open state, the first valve body 30 and the second valve body 40 are arranged at positions where the flow of the LNG is blocked and not disturbed when the LNG flows from the input port 11 to the output port 12 through the intermediate flow path 13. Yes.

  Further, in the arrangement position of the first valve body 30 in the valve open state, the vicinity of the first top 33 </ b> T of the first protrusion 33 in the first base 31 is the wedge 23 of the wedge forming portion 22 </ b> A of the valve stem wedge member 22. The first taper surface 23a is not pressed. Further, in the arrangement position of the second valve body 40 in this state, the vicinity of the second top 43T of the second protrusion 43 on the second base 41 is the wedge 23 of the wedge forming portion 22A of the valve stem wedge member 22. The second taper surface 23b is not pressed.

  Next, in order to change the valve opening state to the valve closing state, the operator rotates the handle 63 in one direction (for example, clockwise direction), and rotates the handle 63 with the male screw 29 and the female screw 69. Is converted into a linear motion by moving the valve rod 20 downward in the second axial direction L2, and the valve rod wedge member 22, the first valve body 30 and the second valve body 40 are lowered. FIG. 2 shows an intermediate state immediately after the lowering first valve body and second valve body come into contact with the body in the intermediate flow path.

  The first valve body 30 and the second valve body 40 are positioned at the lowest position on the inner peripheral surface of the body 10 in the intermediate flow path 13 (the position of the lower line indicated by the intermediate flow path 13 illustrated in FIGS. 1 and 2). ) (The intermediate state), the first valve body 30 and the second valve body 40 remain suspended in the valve-opened state by the upper side surfaces of the hook portions 24 and 24. And although the 1st top part 33T vicinity of the 1st projection part 33 exists in the state which contacted the 1st taper surface 23a of the wedge 23 of the valve stem wedge member 22, it is the free state which is not pressing this 1st taper surface 23a. It has become. Therefore, even if the first valve body 30 is in contact with or close to the first valve seat 14, the first valve body 30 is not pressed against the first valve seat 14. The valve body 30 does not close the first valve seat 14 with a sealing force.

  Further, the vicinity of the second top portion 43T of the second protrusion 43 is in a state where it is in contact with the second taper surface 23b of the wedge 23 of the valve rod wedge member 22, but is not pressing the second taper surface 23b. It has become. Therefore, even if the second valve body 40 is in contact with or close to the second valve seat 15, the second valve body 40 is not pressed against the second valve seat 15. The valve body 40 does not close the second valve seat 15 with a sealing force.

  Next, in order to change from the intermediate state to the valve-closed state, the operator rotates the handle 63 further in one direction from the intermediate state, and moves the valve stem 20 downward in the second axial direction L2 to thereby set the valve stem wedge. The member 22 is lowered. When the valve stem 20 is further lowered from the intermediate position to the lower side in the second axial direction L2, the first tapered surface 23a of the wedge 23 moves relative to the stationary first valve body 30, and the first The position where the vicinity of the first top 33T of the first protrusion 33 of the valve body 30 contacts the first tapered surface 23a of the wedge 23 changes to the wide portion side above the second axial direction L2 in the wedge 23. At the same time, the second tapered surface 23b of the wedge 23 moves relative to the stationary second valve body 40, and the vicinity of the second top 43T of the second protrusion 43 of the second valve body 40 is the wedge 23. The position in contact with the second tapered surface 23 b of the wedge 23 changes to the wide part side on the upper side in the second axial direction L <b> 2 in the wedge 23.

  At this time, the vicinity of the first top 33T of the first protrusion 33 is already in an intermediate state and is in contact with the first taper surface 23a of the wedge 23. Therefore, the valve stem wedge member 22 is further lowered from the intermediate state. As shown in FIG. 3, a valve closing pressing force F that presses the valve rod wedge member 22 downward in the second axial direction L2 is required. The valve closing pressing force F is generated by moving the valve rod 20 downward in the second axial direction L2. The valve closing pressing force F that has acted on the valve rod wedge member 22 acts locally in the vicinity of the first top 33T of the first protrusion 33 that contacts the first taper surface 23a of the wedge 23, and thus the first axial direction L1. Is divided into a component force Fa parallel to the input port side and a component force acting on the lower side in the second axial direction L2. The first valve body 30 is pressed by the input port side component Fa received in the vicinity of the first top 33T of the first protrusion 33 until the first valve body 30 can be in close contact with the first valve seat 14. In order to increase the adhesion force to the first valve seat 14, the valve closing pressure F is increased to further lower the valve rod wedge member 22, and the input port side component Fa is further increased to increase the first valve seat. The first base portion 31 of the first valve body 30 is pressed against the first valve seat 14 so that the contact surface pressure (seal force) of the first contact surface 31 a that contacts the contact member 14 increases. Thus, the first valve body 30 and the first valve seat 14 come into contact with each other with a large sealing force so that LNG does not leak, and the valve is closed.

  Since the vicinity of the first top 33T of the first protrusion 33 and the vicinity of the second top 43T of the second protrusion 43 are already in an intermediate state and in contact with the second tapered surface 23b of the wedge 23, the valve In order to further lower the rod wedge member 22 from the intermediate position, a valve closing pressing force F that presses the valve rod wedge member 22 downward in the second axial direction L2 is required as shown in FIG. As described above, the valve closing pressing force F is a pressing force already generated when the valve closing pressing force F is locally applied in the vicinity of the first top 33T of the first protrusion 33 that contacts the first tapered surface 23a of the wedge 23. is there. The valve closing pressing force F acting on the valve rod wedge member 22 acts locally in the vicinity of the second top 43T of the second protrusion 43 that contacts the second taper surface 23b of the wedge 23, and the first axial direction L1. Are divided into an output port side component force Fb parallel to the second axial direction L2 and a component force acting on the lower side in the second axial direction L2. The second valve body 40 is pressed by the output port side component force Fb received at the second top portion 43T of the second protrusion 43 until the second valve body 40 can be brought into close contact with the second valve seat 15. In order to increase the adhesion force to the second valve seat 15, when the valve closing pressure F is further increased and the valve rod wedge member 22 is lowered, the input port side component Fa becomes larger and at the same time the output port side The component force Fb also increases. And the 2nd base 41 of the 2nd valve body 40 is pressed to the 2nd valve seat 15 so that the contact surface pressure (sealing force) of the 2nd contact surface 41a contact | abutted with the 2nd valve seat 15 may become large. Thus, the second valve body 40 and the second valve seat 15 abut against each other with a large sealing force so as to prevent LNG from leaking and close the valve.

  In addition, when the valve stem wedge member 22 is lowered by applying a valve closing pressing force F to the valve stem 20 to generate the input port side component Fa, as shown in FIG. The hooks 24, 24 are separated from the upper side surfaces of both the first slit 35 of the first base 31 of the first valve body 30 and the second slit 45 of the second base 41 of the second valve body 40, and the lower side Approach the side. And when the hook parts 24 and 24 contact the lower side surfaces of both the first slit 35 of the first base 31 of the first valve body 30 and the second slit 45 of the second base 41 of the second valve body 40. Further, the first valve body 30 cannot be pressed against the first valve seat 14 and the second valve body 40 cannot be pressed against the second valve seat 15 with more force. Therefore, in the normal use range of the gate valve 1, the first and second valve bodies 30, the hooking portion 24 are not in contact with the lower side surfaces of both the first slit 35 and the second slit 45. The first slit 35 and the second slit 45 are set with a margin in the width in the second axial direction L2 between the first slit 35 and the second slit 45 so that a sufficient tightening force by 40 can be obtained. It is important to keep it.

  In order to change from the closed state to the open state, the handle 63 may be rotated in the other direction (for example, counterclockwise direction), and the description thereof will be omitted.

Here, in order to confirm the valve closing performance on the secondary side (output port 12 side) of the gate valve 1, the pressure of the flowing fluid, the amount of fluid leakage between the second valve body and the second valve seat, A confirmation survey was conducted on the relationship with the rotation angle of the handle necessary to generate the valve closing pressure.
The survey conditions are
(1) Fluid: N ₂
(2) Fluid temperature: 20 ° C (room temperature)
(3) Primary pressure of fluid: 1.5 (MPa), 3.0 (MPa), 5.47 (MPa), 7.44 (MPa)
(4) Time for closing and shutting off the flow of fluid: 2 (min.)
(5) Reference angle of the handle: the second valve body 40 is in contact with the second valve seat 15 but the second valve body 40 is not pressing the second valve seat 15 (shown in FIG. 2) State) is a steering wheel rotation angle 0 (deg.).
(6) Maximum allowable rotation angle of the handle: 360 (deg.)
(7) Number of repeated investigations: When the handle rotation angle is 45 (deg.), Any primary side pressure is 3 times, and when 180 (deg.), The primary side pressure is 7.44 (MPa) twice.

The survey results are shown in FIG. As can be easily understood from FIG. 7, when the primary pressure is in the range up to 5.47 (MPa), the output port necessary for closing the second valve body 40 against the second valve seat 15 is provided. If the steering wheel rotation angle is rotated by 45 (deg.) To apply the side component force Fb, N ₂ leakage from the second valve body 40 and the second valve seat 15 becomes 0 (cc / min.). It can be seen that the intermediate flow path 13 and the output port 12 side are sufficiently airtight. On the other hand, when the primary pressure becomes 7.44 (MPa), it is necessary to close the second valve body 40 against the second valve seat 15 in order to prevent N ₂ leakage in a stable state. It can be seen that the handle 63 needs to be rotated to 180 (deg.) In order to apply the output port side component force Fb.

  Next, the survey results are considered. In a no-load state where the valve closing pressing force F from the valve stem 20 is not transmitted to the second valve body 40, the rotational torque of the handle 63 was 2.5 (N · m). When the primary pressure was 1.5 (MPa), the handle rotation angle of the handle 63 until the valve could be closed without leakage was 45 (deg.). On the other hand, in the closed valve load state when the output valve side component force Fb is applied to bring the second valve body 40 into contact with the second valve seat 15 and the valve is closed, the rotational torque of the handle 63 is 3 (N -M). That is, in order to generate the output port side component force Fb that presses the second valve body 40, the operator only has to rotate the handle 63 with a rotational torque of substantially 0.5 (N · m). Such a rotational torque value of 0.5 (N · m) is light enough that no load is applied to the handle 63, and light enough not to be tightened by the handle 63 (load due to rotation). Yes. Of course, even when the pressure on the primary side is other than 1.5 (MPa), the result is that there is almost no rotational load on the handle 63 associated with the operator.

On the other hand, instead of the first and second valve bodies 30 and 40, a conventional valve body made of metal in which two valve bodies are integrally formed in a wedge shape is used as a prior art gate valve. A conventional partition having a structure in which the conventional valve body is brought into contact with the conventional valve seat to close the valve by transmitting the pressing force from the valve stem to the conventional valve body in surface contact with the wedge portion corresponding to 22A. The confirmation survey described above was also conducted for the valves. According to the investigation, the handle wheel is rotated from the state in which the conventional valve body is in contact with the conventional valve seat to the valve closed state, so that the N ₂ leakage becomes 0 (cc / min.). In order to apply the component force, the substantial rotational torque was about 13 (N · m). In other words, in the prior art gate valve, the handle wheel had to be rotated with a rotational torque of about 13 (N · m) in order to obtain the closing force of the conventional type valve body necessary for closing. In the gate valve 1 of the present embodiment, as described above, it may be rotated with a rotational torque of 0.5 (N · m). Therefore, if the gate valve 1 of this embodiment is used, it is significant in that the closing force required to close the valve can be suppressed by about 97% smaller than that of the gate valve of the prior art. Was verified.

  The operation and effect of the gate valve 1 according to this embodiment having the above-described configuration will be described.

(1) The body 10 in which the first valve body 30, the second valve body 40, the input port 11 and the output port 12 are formed on the first axis AX across the intermediate flow path 13, and the intermediate flow path 13 The first valve seat 14 formed on the input port 11 side, the second valve seat 15 formed on the output port 12 side with respect to the intermediate flow path 13, the first tapered surface 23a and the second tapered surface 23b And a valve stem wedge member 22 connected to a valve stem 20 that is movable in a second axial direction L2 perpendicular to the first axial direction L1 along the first axial line AX. The valve stem wedge member 22 that is interlocked with the movement of the first valve seat 30 moves the first valve body 30 and the second valve body 40 to the opposite sides with respect to the first axial direction L1 simultaneously. 14, the first valve body 30 and the second valve seat 15 are the same as the second valve body 40, respectively. In the gate valve 1 that controls the flow of the LNG flowing through the intermediate flow path 13 by abutting or separating from the first flow path 30, the first valve body 30 abuts against the first valve seat 14 in the first axial direction L1. On the side opposite to the first abutting surface 31a, there is a first protrusion 33 that projects to form a first apex 33T, and the second valve body 40 has a second valve seat 15 with respect to the first axial direction L1. On the opposite side of the second abutting surface 41a that abuts against the second abutting surface 41a, the second abutting portion 43T is formed to project and the second projecting portion 43 projects, and the first projecting portion 33 is in contact with the first tapered surface 23a. Simultaneously with the sliding, the second projecting portion 43 slides in contact with the second tapered surface 23b, whereby the first valve body 30 and the second valve body 40 are moved to the first valve seat 14 and the second valve body 40, respectively. Since the valve seats 15 are in contact with each other and are closed, the first valve body 30 is connected to the first valve seat. 4. To close the second valve body 40 by contacting the second valve body 40 with the second valve seat 15 respectively, the valve closing pressing force F of the valve rod 20 applied to the lower side (one side) in the second axial direction L2 is: It is transmitted to the valve rod wedge member 22 and is divided into an input port side component Fa acting on the input port 11 side and an output port side component Fb acting on the output port 12 side in the first axial direction L1. At this time, the vicinity of the first top 33T of the first protrusion 33 and the first tapered surface 23a of the valve stem wedge member 22 and the vicinity of the second top 43T of the second protrusion 43 and the second of the valve stem wedge member 22 are the same. When the taper surface 23b slides, the first protrusion 33 side and the second protrusion 43 side are in contact with each other in a substantially point contact state.

  That is, in the gate valve 1 of the present embodiment, the point contact position between the vicinity of the first top 33T of the first projection 33 and the first taper surface 23a of the valve rod wedge member 22 and the second projection 43 second. When the point contact position between the vicinity of the top 43T and the second tapered surface 23b of the valve rod wedge member 22 is located on the first axis AX of the intermediate flow path 13, the first valve body is caused by the input port side component Fa. 30 is pressed to contact the first valve seat 14 to close the valve. At this time, the contact portion between the first valve body 30 and the first valve seat 14 with respect to the radial direction centered on the first axis AX is the entire circumference of the first valve seat 14 centered on the first axis AX. Thus, the contact portions are more uniform, and the sealing force of the first valve body 30 that contacts the first valve seat 14 can be obtained in a stable state. At the same time as the first valve body 30 is pressed and the first valve seat 14 is closed, the second valve body 40 is pressed and contacted with the second valve seat 15 by the output port side component force Fb to close the valve. Let At this time, the contact portion between the second valve body 40 and the second valve seat 15 with respect to the radial direction centered on the first axis AX is the entire circumference in the circumferential direction of the second valve seat 15 centered on the first axis AX. Thus, the sealing force of the second valve body 40 that becomes more uniform and contacts the second valve seat 15 can be obtained in a stable state. The point contact position between the vicinity of the first top 33T of the first protrusion 33 and the first tapered surface 23a of the valve stem wedge member 22, and the vicinity of the second top 43T of the second protrusion 43 and the valve stem wedge member 22 The point contact position with the second taper surface 23b is a balanced position on both the left and right sides of the valve stem wedge member 22. Therefore, a difference in sealing force is unlikely to occur between the sealing force of the first valve body 30 that contacts the first valve seat 14 and the sealing force of the second valve body 40 that contacts the second valve seat 15. Further, due to the assembly accuracy at the time of manufacturing the gate valve 1, the sealing force of the first valve body 30 that contacts the first valve seat 14 and the second valve body 40 that contacts the second valve seat 15. Difference in sealing force from sealing force is unlikely to occur.

  In particular, the point contact position between the vicinity of the first top 33T of the first protrusion 33 and the first tapered surface 23a of the valve stem wedge member 22, and the vicinity of the second top 43T of the second protrusion 43 and the valve stem wedge The point contact position with the second taper surface 23 b is located on the first axis AX of the intermediate flow path 13, the first protrusion 33 at the center of the first valve body 30, and the center of the second valve body 40. If each of the second protrusions 43 is arranged, the direction of the input port side component force Fa and the direction of the output port side component force Fb are in the first axial direction L1 even if the gate valve 1 is used for a long period of time. A straight orientation is maintained along. Therefore, the sealing force of the first valve element 30 that contacts the first valve seat 14 and the sealing force of the second valve element 40 that contacts the second valve seat 15 are both on the upper and lower sides with the first axis AX as a boundary. By acting equally on the entire circumferential direction of the first valve seat 14 and the entire circumferential direction of the second valve seat 15, it is possible to maintain a stable state while suppressing a decrease over time. Further, the vicinity of the first top 33T of the first protrusion 33 and the first taper surface 23a of the valve stem wedge member 22 and the vicinity of the second top 43T of the second protrusion 43 and the second taper of the valve stem wedge member 22 are provided. Since the surface 23b is almost point contact, the wear on the both sides of the wedge portion is uneven compared to the conventional gate valve that slides in contact with the wedge contact surface of each pressing member. It is hard to do. Therefore, even if the opening / closing operation of the valve is repeated a plurality of times, the first valve body 30 and the second valve body 40 are respectively connected to the first valve seat 14 and the second valve seat 15 so that fluid (LNG) does not leak. It is possible to maintain the contact in a uniform state and close the valve with a slight contact force and a high contact force for a longer period. Even when the fluid to be controlled is a flammable fluid such as LNG at a cryogenic temperature of below 162 ° C. as in this embodiment, it is maintained that the valve is closed with high adhesion so that fluid (LNG) does not leak. it can.

  Further, the vicinity of the first top 33T of the first protrusion 33 and the first tapered surface 23a of the wedge 23, and the vicinity of the second top 43T of the second protrusion 43 and the second tapered surface 23b of the wedge 23, In any case, the valve closing pressing force F of the valve rod 20 that is substantially point contact and is applied to one side in the second axial direction L2 is from the center of the first valve body 30 via the first protrusion 33 to the first valve seat 14. And directly from the center of the second valve body 40 to the second valve seat 15 via the second protrusion 43. Therefore, the relative wear between the vicinity of the first top 33T of the first protrusion 33 and the first tapered surface 23a, and the relative wear between the vicinity of the second top 43T of the second protrusion 43 and the second tapered surface 23b. As compared with the conventional gate valve in which each taper surface of the wedge portion and each wedge portion abutting surface of the pressing member are brought into surface contact and slid, it can be suppressed. Therefore, the number of maintenance operations for exchanging or repairing a worn portion or the like can be reduced, and the cost can be reduced. In addition, even if the valve opening / closing operation is repeated a plurality of times, the valve stem wedge member 22 and the first protrusion 33 of the first valve body 30 and the second protrusion 43 of the second valve body 40 are worn. Since it is difficult, the wear powder hardly mixes into the LNG flowing in the flow path. In particular, when the fluid to be controlled is a flammable fluid (LNG) having a cryogenic temperature of below 162 ° C. as in the present embodiment, the first valve body 30 and the second valve caused by the wear powder mixed into the LNG. The maintenance frequency of the body 40 and the like can be suppressed to a lower level, and the maintenance cost can be reduced.

  Therefore, in the gate valve 1 of the present embodiment, even if the opening / closing operation of the valve is repeated a plurality of times, it is possible to prevent the wear powder from entering the LNG and to close the valve with a stable sealing force. Play.

(2) Since both the first protrusion 33 and the second protrusion 43 are formed in a hemispherical shape, the valve closing pressing force F to the valve rod 20 is the first valve body. When the first valve body 30 is pressed by the input port side component Fa acting on the first tapered surface 23a of the valve stem wedge member 22 and moves to the input port 11 side, the hemispherical first projection The contact portion with the portion 33 moves on the first tapered surface 23 a of the valve stem wedge member 22. At the same time, when the second valve body 40 is pressed by the output port side component force Fb acting on the second tapered surface 23b of the valve rod wedge member 22 and moves to the output port 12 side, the hemispherical second protrusion 43 is formed. The contact portion moves with the second taper surface 23 b of the valve stem wedge member 22. Thereby, the valve stem wedge member 22 does not wear at the same portion of the first tapered surface 23a and at the same portion of the second tapered surface 23b. Further, if both the first protrusion 33 and the second protrusion 43 are formed in a hemispherical shape, the first top 33T of the first protrusion 33 with respect to the first taper surface 23a of the valve stem wedge member 22 is formed. The state of contact with the vicinity (such as the contact surface and angle) is unlikely to change over time. Further, the contact state (contact surface, angle, etc.) of the second protrusion 43 with the second taper surface 23b of the valve stem wedge member 22 in the vicinity of the second apex 43T hardly changes over time.

  Therefore, the direction of the input port side component force Fa and the direction of the output port side component force Fb are easily maintained in a straight direction along the first axial direction L1 during a longer period of use of the gate valve 1. The sealing force of the first valve body 30 that contacts the first valve seat 14 and the sealing force of the second valve body 40 that contacts the second valve seat 15 are suppressed from decreasing over time, and are in a stable state. Can be maintained. As a result, the first valve body 30 contacts the first valve seat 14 and the second valve body 40 contacts the second valve seat 15 in a uniform state over the entire circumference of each contact portion. ) In order to prevent leakage, it is possible to maintain the contact and close with a high contact force for a longer period of time.

  Further, the wear of the first tapered surface 23a of the valve stem wedge member 22 and the vicinity of the first top portion 33T of the first protrusion 33 of the first valve body 30, and the second tapered surface 23b of the valve stem wedge member 22 and the second tapered surface 23b. Wear with the vicinity of the second top of the second protrusion 43 of the valve body 40 can be further reduced. Therefore, each of the valve stem 20 according to the present embodiment and the conventional gate valve in which both side tapered surfaces of the wedge portion and the wedge contact surface of each pressing member are brought into surface contact and slid are provided. In the gate valve 1 of the present embodiment, when the valve closing pressing force F (pressing force) is applied with the same magnitude, the input port required to bring the first valve body 30 into contact with the first valve seat 14 The side component force Fa and the output port side component force Fb necessary to bring the second valve body 40 into contact with the second valve seat 15 can be further reduced, and the valve closing pressure on the valve rod 20 is reduced. Loss of force transmitted from F to the first valve body 30 and the second valve body 40 can be reduced. Therefore, in order to close both the first valve body 30 side and the second valve body 40 side, the valve rod 20 applied with the valve closing pressing force F is moved downward in the second axial direction L2, and the valve rod wedge is moved. A conventional gate valve in which the valve closing pressing force F on the lower side in the second axial direction L2 applied to the member 22 is slid by bringing both side taper surfaces of the wedge portion and the wedge contact surface of each pressing member into surface contact with each other. It can be made smaller than

  In particular, in order to adjust the valve closing pressure F applied to the valve rod wedge member 22 by the gate valve of the gate valve 1 of the present embodiment, the handle 63 connected to the valve rod 20 is operated as in the present embodiment. Even when the structure is rotated manually by the user, the direction of the input port side component force Fa and the direction of the output port side component force Fb are maintained while maintaining a straight direction along the first axial direction L1. It becomes easy. Therefore, when the operator rotates the handle 63 in one direction at the time of the valve closing operation, the tightening force by the first and second valve bodies 30 and 40 for closing the valve and shutting off the LNG is also tapered on both sides of the wedge portion. Compared to the conventional gate valve in which the surface and the wedge contact surface of each pressing member are brought into surface contact with each other and slid, the pressure can be kept small, and the burden on the operator related to the valve closing operation can be reduced.

  Further, as with the gate valve 1 of the first embodiment, in order to adjust the valve closing pressing force F applied to the wedge portion 23, the handle 63 connected to the valve rod 20 is rotated by manual operation by an operator. In the case of the manually operated gate valve 1, the tightening force for blocking the LNG by the first and second valve bodies 30 and 40 can be reduced, so that the screw (male screw 29 and female screw) for moving the valve stem 20 up and down is reduced. Screw 69) The pitch can be increased. As a result, a structure in which the valve stem is provided with a screw so that the number of rotations of the handle 63 accompanying the opening and closing of the first and second valve bodies 30 and 40 converts the rotational motion of the handle wheel into the vertical motion of the valve stem. Compared to the conventional gate valve composed of

  Moreover, in the gate valve 1 of this embodiment, when both the 1st projection part 33 and the 2nd projection part 43 are formed, for example with metal, the 1st top part 33T vicinity of the 1st projection part 33 and The first taper surface 23a of the valve stem wedge member 22 and the vicinity of the second top 43T of the second protrusion 43 and the second taper surface 23b of the valve stem wedge member 22 are both close to point contact. Since it can contact, the wear mentioned above becomes small. And preferably, a measure for giving wear resistance to the first protrusion 33 and the second protrusion 43 is taken.

  By the way, in the conventional gate valve in which the both-side tapered surfaces of the wedge portion and the wedge-contact surface of each pressing member are brought into surface contact and slid, the one-side component force acting on the input port side and the output port side In order to cause the other side component force to act on the straight line along the flow path direction, for example, flatness, parallelism, etc., with respect to the tapered surface of the wedge portion and the wedge portion contact surface of the pressing member It is necessary to manufacture with high processing accuracy and assembly accuracy. In addition, if a measure against wear is applied to the taper surface and the wedge contact surface of the pressing member, the gate valve becomes expensive. Further, since a pressing member is required between the wedge portion and the valve body, the conventional gate valve is expensive.

  On the other hand, in the gate valve 1 of the present embodiment, the vicinity of the first top 33T of the hemispherical first protrusion 33 and the first taper surface 23a of the valve rod wedge member 22 have a hemispherical shape. The vicinity of the second top 43T of the two protrusions 43 and the second taper surface 23b of the valve stem wedge member 22 can be in contact with each other in a state close to point contact. For this reason, when manufacturing the valve stem wedge member 22, there is no counterpart member in surface contact with the first tapered surface 23a and the second tapered surface 23b. The assembly accuracy can be made relatively rough. Moreover, since the 1st projection part 33 and the 2nd projection part 43 are hemispherical shape, with respect to the 1st taper surface 23a and the 2nd taper surface 23b of the valve-rod wedge member 22, these 1st projection parts 33 and 2nd The contact area of the two protrusions 43 is small, and it is not necessary to perform a process having wear resistance. Therefore, the manufacturing cost can be reduced. Further, the gate valve 1 of the present embodiment differs from the conventional gate valve that requires a pressing member between the wedge portion and the valve body, and the valve closing pressing force F acting on the valve rod wedge member 22 is changed to the first value. Since it is directly transmitted to the valve body 30 and the second valve body 40, the number of parts can be reduced and the cost can be reduced.

(3) The first valve body 30 is a separate body from the first protrusion 33 and has a plate-like first base 31 having a first contact surface 31 a, and the first protrusion 33 is formed on the first base 31. The second valve body 40 has a plate-like second base 41 having a second abutting surface 41a, which is separate from the second protrusion 43, and is attached to be detachable. 43 is detachably attached to the second base 41, so that the first protrusion 33 or the second tapered surface 23b is formed between the first tapered surface 23a of the valve stem wedge member 22 and the second tapered surface 23b. Even if the second projecting portion 43 receives and wears frictional force between the first projecting portion 33 and the second projecting portion 43, the first base portion 31 of the first valve body 30 The second base 41 of the second valve body 40 can be used continuously. Moreover, when the 1st valve body 30 comprises the 1st base part 31 and the 1st projection part 33 with a different material, or the 2nd valve body 40, the 2nd base part 41 and the 2nd projection part 43 differ in a material. In such a case, the first valve body 30 and the second valve body 40 can be easily manufactured.

(4) Since at least the first base portion 31 and the second base portion 41 are formed of resin, since the resin is more easily deformed than metal, the first base portion 31 has a first property. The contact surface 31a and the first valve seat 14 are easily in close contact with each other, and the sealing performance of the first valve body 30 that contacts the first valve seat 14 can be largely ensured. In addition, the second contact surface 41a of the second base portion 41 and the second valve seat 15 are easily brought into close contact with each other, and the sealing performance of the second valve body 40 that contacts the second valve seat 15 can be largely ensured.

  In particular, in the gate valve 1 according to the present embodiment, the resin is a composite material resin (PEEK / carbon fiber composite resin) of poly, ether, ether, ketone, and carbon fiber. The material can be maintained at the same level as room temperature even at an extremely low temperature of 162 ° C. below zero. Even if the fluid to be controlled is a flammable fluid such as LNG having a cryogenic temperature of below 162 ° C. as in this embodiment, the PEEK / carbon fiber composite resin is altered by the contact of the flammable fluid. Absent. Therefore, the gate valve 1 of this embodiment is applicable when controlling the flow of such a cryogenic combustible fluid.

  Further, in the gate valve 1 according to the present embodiment, the first base portion 31 is provided with the through hole 31H penetrating in the thickness direction TH along the first axial direction L1, so that the first valve body 30 is the first valve body 30. At the same time as closing the valve seat 14, the volatile fluid is prevented from remaining in the intermediate flow path when the second valve body 40 is closed against the second valve seat 15. can do. That is, when controlling the flow of a volatile fluid such as LNG having a high volatile property at an extremely low temperature of 162 ° C. below zero as in the present embodiment, the first valve body 30 is placed in the first valve seat 14. At the same time as closing the valve, the volatile fluid may remain in the intermediate flow path 13 even when the second valve body 40 is in contact with the second valve seat 15 and closed. . The volatile fluid remaining in the intermediate flow path 13 returns from the intermediate flow path 13 to the input port 11 through the through hole 31H, and the volatile fluid can be prevented from remaining in the intermediate flow path 13.

  In the above, the present invention has been described with reference to the embodiments. However, the present invention is not limited to the above-described embodiments, and can be appropriately modified and applied without departing from the gist thereof.

  For example, in the embodiment, the first contact surface 31a of the first base 31 of the first valve body 30 and the second contact surface 41a of the second base 41 of the second valve body 40 are both flat. . However, the surface shape of the first contact surface of the first base of the first valve body and the second contact surface of the second base of the second valve body is not limited to the embodiment and can be changed as appropriate. As an example, FIG. 8 shows the surface shapes of the first contact surface of the first base portion of the first valve body and the second contact surface of the second base portion of the second valve body according to the modification. As shown in FIG. 8, in the first valve body 30A according to the modified example, the first contact surface 36b connects the first outer flat surface 36a and the first inner flat surface 36c having steps to connect the first valve It is formed by a tapered surface arranged at a position where it can come into contact with the seat 14. Also in the second valve body 40A, the second contact surface 46b connects the second outer flat surface 46a and the second inner flat surface 46c having a step, and is disposed at a position where the second valve seat 15 can contact. The tapered surface is formed.

DESCRIPTION OF SYMBOLS 1 Gate valve 10 Body 11 Input port 12 Output port 13 Intermediate flow path 14 1st valve seat 15 2nd valve seat 20 Valve stem 22 Valve stem wedge member (valve stem wedge part)
23a 1st taper surface 23b 2nd taper surface 30 1st valve body 31 1st base 31H Through-hole 31a 1st contact surface 33 1st projection part 33T 1st top part 40 2nd valve body 41 2nd base 41a 2nd contact Contact surface 43 Second protrusion 43T Second apex AX First axis L1 First axis direction L2 Second axis direction TH Thickness direction

Claims (2)

A first valve body, a second valve body, an input port and an output port are formed on the first axis with the intermediate flow path interposed therebetween, and formed on the input port side with respect to the intermediate flow path A first valve seat, a second valve seat formed on the output port side with respect to the intermediate flow path, a first tapered surface and a second tapered surface are formed in a wedge shape, and a first along the first axis. A valve stem wedge portion connected to a valve stem movable in a second axial direction orthogonal to the axial direction, and the valve stem wedge portion interlocked with the movement of the valve stem is the first valve The first valve body and the second valve seat are moved relative to the first valve seat by simultaneously moving the body and the second valve body in opposite directions with respect to the first axial direction. On the other hand, the flow of the fluid flowing through the intermediate flow path is controlled by the second valve bodies simultaneously contacting or separating from each other. In off valve,
The first valve body has a first protrusion that protrudes to form a first apex on a side opposite to the first contact surface that contacts the first valve seat with respect to the first axial direction. The second valve body has a second protrusion that protrudes to form a second top on the side opposite to the second contact surface that contacts the second valve seat with respect to the first axial direction. about,
The first protrusion is slid in a state in contact with the first tapered surface, and at the same time, the second protrusion is slid in a state in contact with the second tapered surface, whereby the first valve body is The first valve seat and the second valve body abutting and closing each of the second valve seat ;
The first protrusion and the second protrusion are both formed in a hemispherical shape,
The first valve body has a plate-like first base part that is separate from the first protrusion part and has the first contact surface, and the first protrusion part is detachably attached to the first base part. And
The second valve body has a plate-like second base portion that is separate from the second protrusion portion and has the second contact surface, and the second protrusion portion is detachably attached to the second base portion. Being done,
At least the first base and the second base are formed of resin;
A guide member having an opening penetrating in the second axial direction is provided, and the first valve body, the second valve body, and the valve stem wedge portion are formed by an inner surface of the opening portion of the guide member. , Go straight while being held under the restriction of rotation prevention,
A gate valve characterized by. The gate valve according to claim 1,
The first valve body is formed with a through hole communicating the input port and the intermediate flow path,
A gate valve characterized by.

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