JP2000120921A - Slow shutout valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify structure of a slow shut-out valve so as to lower cost by arranging a valve working as a one-way valve when a piston body is positioned between a valve closing position and an intermediate valve opening position and working as an opening/closing valve until the piston body is moved to the intermediate valve opening position after it is moved to the valve opening position. SOLUTION: When a pressure from a pressure source 31 is applied to a valve 40 via a control valve 30 and a flow passage 28, the pressure is applied to a ring type packing 33 via a clearance between a valve rod 41 and a valve rod receiver 42, and the ring type packing 44 is warped while lifted upward for releasing a pressure to a valve opening pressure chamber 26. When the ring type packing 44 is brought into contact with a spacer 45, a communication area is expanded in a diameter expanded flow passage 28a. Therefore, a pressure is applied to a valve opening pressure chamber 26 quickly and a piston body 21 and the valve rod 14 are led. On the other hand, supply of a pilot pressure is cut off, the valve rod 41 is lowered, and if its recess part 41X exceeds the ring type packing 44, these clearances are closed and a function as a one-way valve is restored.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slow-shut valve in which a normally closed valve is rapidly opened, rapidly closed to a certain opening, and then slowly closed.

[0002]

2. Description of the Related Art A slow-shut valve of this type is used, for example, in a fluid piping to protect equipment in the piping from a water hammer phenomenon that occurs when the valve is closed instantaneously. .

[0003] Such a slow-shut function can be obtained by providing a plurality of on-off valves and needle valves that operate in accordance with the moving position of the valve element. However, as the number of valves increases, the number of valves increases. It is inevitable that costs will increase.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a slow-shut valve having a simpler structure and a lower cost while having the above functions.

[0005]

SUMMARY OF THE INVENTION A slow-shut valve according to the present invention is a valve rod having a piston body for operating a valve element which opens and closes a flow path in contact with and away from a valve seat; an urging element for urging the valve rod in a valve closing direction. Means; a valve-opening pressure chamber defined by a piston body and moving the piston body and the valve rod in a valve-opening direction against the biasing means when receiving a pilot pressure; the valve-opening pressure chamber and a pilot pressure source A first valve provided in a flow path that communicates with the first valve and changing a state according to the movement position of the piston body; and a second valve provided in a flow path that communicates the valve-opening pressure chamber to the atmosphere. A throttle valve; wherein the first valve has a fluid flow from the pilot pressure source side to the valve opening pressure chamber side when the piston body is located between the valve closing position and the intermediate valve opening position. Forgive and not the opposite fluid flow It operates as a one-way valve, and operates as an on-off valve that allows fluid flow from the valve-opening pressure chamber until the piston body once moves to the valve-opening position and then moves to the intermediate valve-opening position. .

Specifically, the first valve is, at least, a valve rod which is displaced along with a piston body, an annular packing fitted on the outer periphery of the valve rod, and a piston body which is moved from an open position to an intermediate open position. And a recess formed in a part of the valve rod in the circumferential direction to form a gap between the annular packing and the annular packing.

This annular packing may be an O-ring in principle, but in order to increase the reliability of operation, it is preferable to use an annular packing having a Y-shaped cross section or a V-shaped cross section in which the valve-opening pressure chamber side is open. preferable. In addition, it is preferable that a member (cylinder) into which the valve rod is inserted is formed with a diameter-enlarging passage located on the outer periphery of the annular packing and expanding the area from the pressure source to the valve opening pressure chamber side.

It is desirable to lay a slow motion start position adjusting mechanism for setting the initial position on the valve rod.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fluid passage 12 is provided in a flow passage block 11 located below FIG. 1, and an annular valve seat 13 is formed in a part thereof. A valve body 15 provided at the lower end of a valve rod 14 comes into contact with and separates from the annular valve seat 13 to open and close the fluid passage 12.

The valve rod 14 penetrates through the spacer 16 and the connector sleeve 17 and projects upward in FIG. A bellows 18 is stretched between the lower part of the valve rod 14 and the spacer 16 so that the fluid flowing through the fluid passage 12 does not reach the shaft of the valve rod 14. The valve rod 14 is urged by a compression spring 19 in a valve closing direction in which the valve body 15 is seated on the annular valve seat 13. 17a is a spacer 16 and a connector sleeve 17
Is a lock nut for fixing the lock nut to the flow path block 11.

At the upper end of the connector sleeve 17 in the drawing,
A cylinder 20 including a lower cylinder 20a and an upper cylinder 20b is fixed, and a piston body 21 is fixed to an upper end of the valve rod 14. The piston body 21 includes an upper plate 22, a lower plate 23, and a rolling diaphragm 24 in which an inner edge portion is sandwiched and fixed between the upper plate 22 and the lower plate 23. The outer edge of the rolling diaphragm 24 is sandwiched between the lower cylinder 20a and the upper cylinder 20b.
Are integrated by a lock ring 25, so that
A valve opening pressure chamber 26 is defined between the lower cylinder 20a and the piston body 21.

The lower cylinder 20a is provided with a valve opening pressure chamber 26.
Are connected to a pilot pressure source 31 (FIG. 2) via a control valve 30, and a flow passage 29 that connects the valve-opening pressure chamber 26 to the atmosphere is formed. The flow path 28 is provided with a first 40, and the flow path 29 is provided with a needle valve 50 as a throttle valve.

When the piston body 21 is located between the valve closing position and the intermediate valve opening position, the first valve 40 allows fluid flow from the pilot pressure source 31 to the valve opening pressure chamber 26 side, and vice versa. The fluid acts as a one-way valve (check valve) that does not allow the fluid to flow from the valve-opening pressure chamber 26 side to the atmosphere until the piston body 21 once moves to the valve-opening position and then moves to the intermediate valve-opening position. This valve acts as an on-off valve that allows flow. First,
The structure as a one-way valve will be described. The valve rod 41 located in the flow path 28 is slidably fitted in the valve rod receiver 42 in parallel with the piston body 21, and is always in contact with the piston body 21 by the compression spring 43.

An annular packing 44 is fitted on the outer periphery of the valve rod 41 so as to be movable between a valve rod receiver 42 and a spacer 45. The annular packing 44 of this embodiment has a Y-shaped cross section in which the valve-opening pressure chamber 26 side is open. When a pilot pressure is applied from the pilot pressure source 31 side (downward in the drawing), the Y-shaped section is formed. The part is narrowed to allow fluid flow to the valve opening pressure chamber 26. In addition, an annular packing 44 is provided on the lower cylinder 20a with a
A diameter-enlarging passage 28a is formed to widen the gap between the annular packing 44 and the outer peripheral portion when it is moved to a position where it comes into contact with the annular packing 5. When a pilot pressure is applied from the pilot pressure source 31 side (downward in the figure), the annular packing 44 moves from the normal position to the enlarged-diameter passage 28a to increase the flow passage area. On the other hand, when the pressure from the valve-opening pressure chamber 26 is applied to the annular packing 44 while the supply of the pilot pressure from the pilot pressure source 31 is stopped, the annular packing 44
Moves from the diameter-enlarging passage 28a to a normal position (downward), the Y-shaped portion thereof expands, and the inner peripheral portion thereof is connected to the valve rod 41.
The outer peripheral portion is in close contact with the flow path 28 and does not allow fluid flow from the valve-opening pressure chamber 26 to the atmosphere.

The function of the on-off valve in addition to the function of the one-way valve is provided by a concave portion 41
Provided by X. As shown in FIG. 5 and FIG. 6, the concave portion 41X is formed only in a part in the circumferential direction to obtain a better effect. The recess 41X forms a gap between the inner peripheral surface of the annular packing 44 and the recess 41X when the annular packing 44 reaches the recess 41X due to a change in the relative position between the valve rod 41 and the annular packing 44. Deactivate the function of the one-way valve. That is, it acts to open the flow path 28. The position, size, and depth of the concave portion 41X are determined so that this flow passage opening action is maintained until the piston body 21 once moves to the valve opening position and then moves to the intermediate valve opening position. I have.

As shown in detail in FIG. 4, the needle valve 50 is formed by screwing a needle valve body 52 to a valve receiver 51, and by adjusting the depth of screwing of the distal end needle 52a into the passage 51a. , The flow path area can be adjusted.

The slow-shut valve having the above-mentioned structure operates with characteristics as shown in FIG. 7, for example. When the pilot pressure is not supplied to the valve opening pressure chamber 26, the valve rod 14 is pushed downward in the drawing by the force of the compression spring 19, and the valve body 15 is seated on the annular valve seat 13 to close the fluid passage 12. (Section A in FIGS. 2 and 7). In this closed state, when the pilot pressure from the pilot pressure source 31 is applied to the first valve 40 via the control valve 30 and the flow path 28, the pressure is applied through the gap between the valve rod 41 and the valve rod receiver 42. The annular packing 44, which is affected by the annular packing 44 and has a V-shaped cross section, narrows while moving upward to allow the pilot pressure to flow into the valve opening pressure chamber 26. Before or after this, the annular packing 44 rises until it comes into contact with the spacer 45,
Since the diameter-enlarged flow path 28a exists at the ascending position, the communication area increases. Accordingly, the pilot pressure is quickly applied to the valve opening pressure chamber 26, and this pilot pressure overcomes the force of the compression spring 19, so that the piston body 21 and the valve rod 14 rise, and eventually reach the rising end (fully open position). (Section B in FIG. 3 and FIG. 7). At this time, the concave portion 41X of the valve rod 41 has reached a position corresponding to the annular packing 44.

Next, in order to close the valve, the supply of the pilot pressure is cut off and the flow path 28 is opened to the atmosphere.
The piston body 21 starts descending due to the force, and the valve rod 41 is also pushed down by the piston body 21 and descends. At the rising end of the piston body 21, the concave portion 41X
Therefore, there is a gap between the annular packing 44 and the concave portion 41X. Therefore, the pressurized air in the valve opening pressure chamber 26 is released to the atmosphere through the gap between the concave portion 41X and the annular packing 44, and as a result, the piston body 21 and the valve rod 41 descend together. Then, when the valve rod 41 descends relatively to the annular packing 44 and its concave portion 41X exceeds the annular packing 44 (when the cylindrical portion of the valve rod 41 comes into contact with the annular packing 44), the concave portion 41X and the annular packing 44 The gap between is closed. That is, the function as the one-way valve is restored (section C in FIGS. 4 and 7).

Thereafter, the discharge of the compressed air from the valve opening pressure chamber 26 is performed slowly through the needle valve 50 (section D in FIG. 7). The valve closing speed in this section D can be performed by adjusting the amount of screwing of the needle valve 50 to the valve receiver 51 of the needle valve 50 (adjustment of the flow path area).

The first valve 40 is provided with a slow operation start position adjusting mechanism 47 for setting an initial position of the valve rod 41. This slow motion start position adjusting mechanism 47
Is for indirectly adjusting the vertical position of the valve rod 41 by adjusting the vertical position of the valve rod receiver 42. The lower end of the valve rod receiver 42 is in contact with the vertical position adjusting plate 48. The position of the vertical position adjusting plate 48 can be adjusted with the vertical adjusting screw 49. When the initial position of the valve rod 41 is adjusted by the slow motion start position adjusting mechanism 47, the one-way valve function of the first valve 40 is restored after the piston body 21 (valve rod 14) once reaches the fully open position. (The height E in FIG. 7) can be adjusted.

In the above embodiment, the present invention is applied to a bellows valve. However, the present invention is widely applied to a metal diaphragm valve for preventing breakage of equipment due to a water hammer phenomenon and a normal on-off valve. Can be.

In the above embodiment, the valve rod 1
Although the valve body 15 is provided integrally at the lower end of the valve body 4, the present invention can also be applied to a valve structure in which the two are separated and the movement of the valve rod is transmitted to the valve body via a motion transmitting mechanism.

[0023]

As described above, according to the present invention, it is possible to easily open a normally closed valve rapidly, then quickly close the valve to a certain opening, and then slowly close the valve. It can be obtained with a simple structure.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a closed state of an embodiment of a slow-shut valve according to the present invention.

FIG. 2 is an enlarged sectional view of a main part immediately after the opening operation of the slow-shut valve of FIG. 1 is started.

FIG. 3 is an enlarged cross-sectional view showing a state where a valve closing operation is started after the valve opening is completed.

FIG. 4 is an enlarged cross-sectional view illustrating a state in which an intermediate valve is opened after the valve is opened.

FIG. 5 is a front view of a single valve rod of the first valve.

FIG. 6 is a sectional view taken along the line VI-VI in FIG. 5;

FIG. 7 is a diagram showing an example of the opening / closing characteristics of the slow-shut valve of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Flow path block 12 Fluid passage 13 Annular valve seat 14 Valve rod 15 Valve body 19 Compression spring 20 Cylinder 21 Piston body 24 Rolling diaphragm 26 Opening pressure chamber 28 29 Flow path 30 Control valve 31 Pilot pressure source 40 First valve 41 Valve rod 41X Recess 44 Annular packing 47 Slow operation start position adjustment mechanism 48 Vertical position adjustment plate 50 Needle valve (throttle valve)

Claims (5)

[Claims] 1. A valve rod having a piston body for operating a valve body that opens and closes a flow path in contact with and separated from a valve seat; biasing means for biasing the valve rod in a valve closing direction; A valve opening pressure chamber for moving the piston body and the valve rod in a valve opening direction against the urging means when receiving a pilot pressure; and a flow passage for communicating the valve opening pressure chamber with a pilot pressure source. A first valve provided to change the state according to the movement position of the piston body;
And a throttle valve as a second valve provided in a flow path that communicates the valve-opening pressure chamber to the atmosphere. The first valve has a piston body between a closed position and an intermediate open position. When the piston body is moved to the valve opening position, the fluid flows from the pilot pressure source side to the valve opening pressure chamber side, but does not allow fluid flow in the opposite direction. A slow-shut valve that functions as an on-off valve that allows fluid flow from the valve-opening pressure chamber side until it moves to the valve-opening position. 2. The slow-shut valve according to claim 1, wherein the first valve has a valve rod displaced along with the piston body, an annular packing fitted on the outer periphery of the valve rod, and an open piston element. A slow-shut valve having a recess formed in a part of the valve rod in a circumferential direction to form a gap between the annular packing when the valve is located at an intermediate valve opening position from a valve position. 3. The slow-shut valve according to claim 2, wherein the annular packing has a cross section Y in which a valve-opening pressure chamber side is open.
A slow shut valve having a V-shaped or V-shaped cross section. 4. The slow-shut valve according to claim 2, further comprising: a member through which a valve rod is inserted.
A slow shut valve located on the outer periphery of the annular packing and provided with a diameter-enlarging passage for increasing the area from the pressure source to the valve opening pressure chamber side. 5. The slow-shut valve according to claim 2, further comprising a slow-operation start position adjusting mechanism for setting an initial position of the valve rod.