JP2016118989A - Gas leakage prevention device and pressure governor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a gas leakage in a simple structure without inviting the deterioration of the function of a pressure governor.SOLUTION: A gas leakage prevention device includes: a cylindrical main body 20a; a valve seat 22 provided in the main body 20a; a valve body 23 abutting to the valve seat 22 from one end side A1 of an axial direction A and capable of blocking the flow of a fluid in the inner part of the main body; and a spring 24 for energizing the valve body 23 to the other side A2 of the axial direction A. The main body 20a is fixed to an air hole so as to apply the outside pressure to a diaphragm from the other end side A2 to one end side A1. When there is no possibility for the gas leakage, a sum of the gravity force of the valve body 23 and the elastic force of the spring 24 is directed at least to one end side A1 in a state that the valve body 23 abuts against the valve seat 22, and when there occurs a possibility of the gas leakage, the sum of the gravity force of the valve body 23, the elastic force of the spring 24, and the pressure applied to the valve body 23 due to the gas leakage is at least directed to the other end side A2 in a state that the valve body 23 abuts against the valve seat 22.SELECTED DRAWING: Figure 2

Description

  The present invention is provided at a predetermined position of the gas flow passage and regulates the pressure of the gas supplied from the primary pipe upstream from the predetermined position using the external pressure applied to the diaphragm through the air hole. In addition, the present invention relates to a gas leakage prevention device for preventing gas leakage in a pressure regulator that is supplied to the secondary pipe downstream from the predetermined position.

  As a pressure regulator provided in the gas flow passage, a governor is used that adjusts the gas pressure by adjusting the opening degree of the valve port for communicating the primary side pipe and the secondary side pipe. More specifically, this type of governor has a structure in which a valve body that opens and closes a valve opening in accordance with the displacement is attached to a diaphragm that is displaced by receiving the gas pressure of the primary side pipe.

  The diaphragm in the governor may be damaged during long-term use. When the diaphragm is damaged, there is a risk of gas leakage from the air hole for applying back pressure to the governor diaphragm. In order to make the governor safe to use, it is important to prevent gas leakage even if the diaphragm is damaged.

  Conventionally, as a measure for preventing such gas leakage, a configuration in which a double diaphragm is provided in a pressure regulator is known. Further, as shown in Patent Document 1, another diaphragm (detection diaphragm) is connected through an air hole for applying a back pressure to the diaphragm in the pressure regulator, and gas leakage is caused based on the displacement of the detection diaphragm. A configuration is known that detects and closes a shielding valve that shuts off the gas flow in the secondary pipe.

JP 58-5016 A

  However, the configuration in which the above-described diaphragm is doubled has a problem in that the structure of the governor is complicated, and there is a concern that the function may be deteriorated such that followability to pressure fluctuations is reduced, and the cost is increased. Further, in the configuration disclosed in Patent Document 1, the apparatus configuration other than the governor is complicated, and there is a large cost problem such as the need to process the secondary pipe of the gas flow passage. For this reason, there is generally a problem that many governors that do not have a gas leakage prevention function are used.

  Accordingly, an object of the present invention is to prevent gas leakage with a simple structure as a means for developing an infrastructure that can safely use gas without causing a decrease in the function of the pressure regulator. Another object is to provide a gas leakage prevention device that can be used for a pressure regulator that does not have an existing gas leakage prevention function.

In order to achieve the above object, the gas leak prevention device according to the present invention is characterized in that the pressure of gas supplied from a primary pipe upstream of the predetermined position is set at a predetermined position of the gas flow passage. A gas leakage prevention device for preventing gas leakage in a pressure regulator that supplies pressure to a secondary pipe downstream from the predetermined position after pressure regulation using an external pressure applied to the diaphragm through a hole. And
A cylindrical main body configured to allow fluid to flow axially therein;
A valve seat provided inside the main body;
A valve body that is in contact with the valve seat from one end side in the axial direction and is provided so as to be able to block the flow of fluid inside the main body;
A spring for urging the valve body in the axial direction,
The body is fixed to the air hole so as to apply an external pressure to the diaphragm from the other end side in the axial direction toward the one end side,
When there is no possibility of gas leakage in the pressure regulator, the sum of the gravity of the valve body and the elastic force of the spring is at least one end in the axial direction when the valve body is in contact with the valve seat. Head to the side
The pressure applied to the valve body due to the gravity of the valve body, the elastic force of the spring, and the gas leakage in a state where the valve body is in contact with the valve seat when a gas leak may occur in the pressure regulator. Is at least a point that is configured to be directed toward the other end side in the axial direction.

According to the above characteristic configuration, the main body of the gas leakage prevention device is fixed to the air hole of the pressure regulator, and when there is no possibility of gas leakage in the pressure regulator, the valve body is in contact with the valve seat. Since the sum of the gravity of the body and the elastic force of the spring is directed to at least one end side in the axial direction, the valve body is separated from the valve seat, and the fluid flows through the main body. For this reason, external pressure outside the pressure regulator is applied to the diaphragm of the pressure regulator, and the pressure regulator can operate normally.
In addition, when the possibility of gas leakage begins to occur in the pressure regulator due to, for example, damage to the diaphragm (that is, when the pressure of the fluid flowing into the air hole increases), the valve element contacts the valve seat. In the contacted state, the sum of the gravity of the valve body, the elastic force of the spring, and the pressure applied to the valve body due to gas leakage is directed at least to the other end side in the axial direction, so that the valve body comes into contact with the valve seat. For this reason, when the gas leak begins to occur in the pressure regulator, the flow of the fluid inside the main body is interrupted, and the gas can be prevented from leaking out from the pressure regulator.
As described above, the simple configuration including the cylindrical main body, the spring, the valve seat, and the valve body eliminates the gas leakage without causing the function of the pressure regulator to deteriorate in a state where no gas leakage occurs (normal time). Can be prevented.

A further characteristic configuration is that the body is
A position variable mechanism configured to variably change the position in the axial direction on the other end side in the axial direction from the valve seat;
A regulating portion for regulating movement of the valve body from the other end side in the axial direction to the one end side on the one end side in the axial direction from the valve body, and the one end side in the axial direction of the spring includes the Fixed to the disc,
The other end side of the spring in the axial direction is fixed to the position variable mechanism.

  According to the above characteristic configuration, the one end side of the spring is fixed to the position variable mechanism, and the movement of the valve body to the one end side from the restricting portion is restricted by the restricting portion. Therefore, the length of the spring can be changed by adjusting the position of the position variable mechanism in the axial direction in a state where the movement of the valve body to the one end side is regulated by the regulating portion, and there is no gas leakage It is possible to adjust the elastic force of the spring during normal operation. Therefore, for example, pressure regulators having different configurations such as gas types and sizes flowing in the gas flow passages can be used by adjusting at the time of fixing. That is, it is possible to provide a gas leakage prevention device that can be mass-produced by ensuring versatility and that can reduce the manufacturing cost.

In another feature configuration, the position variable mechanism is
A position fixing portion fixed to the main body;
A screw threaded portion provided in the position fixing portion;
A screw screwed into the screw threaded portion;
A fixing member fixed to one end of the screw in the axial direction,
The other end side of the spring in the axial direction is fixed to the fixing member.

  According to the above characteristic configuration, the spring is fixed to the fixing member, and when the screw screwed to the screw screwing portion is rotated, the fixing member fixed to the end portion on one end side of the screw moves in the axial direction. Therefore, by rotating the screw, the total length of the spring can be changed and the elastic force of the spring can be adjusted. That is, versatility can be ensured by a simple configuration in which a screw fixing portion is provided in the position fixing portion and a fixing member is provided in the end portion of the screw. Further, since the elastic force of the spring can be adjusted only by rotating the screw, the operator can easily adjust the elastic force when fixing the gas leakage prevention device to the pressure regulator. That is, it is possible to provide a gas leakage prevention device that is excellent in versatility and excellent in workability during fixing.

Furthermore, another characteristic configuration is that the main body is
Provided with a body-side screw threaded portion on the other end side in the axial direction,
The position variable mechanism is
A cylindrical threaded body provided with a variable part side screw threaded part that is threadedly engaged with the main body side threaded thread part;
A screwed body fixing portion fixed inside the screwed body,
The other end of the spring is
It is in the point fixed to the said screwing body fixing | fixed part of the said position variable mechanism.

  According to the above characteristic configuration, the gas leakage prevention device includes the main body and the screwed body, and the spring is fixed to the screwed body fixing portion. By rotating the main body and the screwed body, the screwed body moves in the axial direction with respect to the main body. Therefore, by rotating the screwed body, the overall length of the spring can be changed and the elastic force of the spring can be adjusted. That is, versatility can be ensured by a simple configuration including a main body and a screwed body and screwed by a screw threaded portion. In addition, since the elastic force of the spring can be adjusted only by rotating the screwed body, the operator can easily adjust the elastic force when fixing the gas leakage prevention device to the pressure regulator. That is, it is possible to provide a gas leakage prevention device that is excellent in versatility and excellent in workability during fixing.

According to another characteristic configuration, the pressure regulator includes an air hole-side screwed portion on an inner peripheral surface of the air hole,
The main body is provided with an outer peripheral surface screwed portion that engages with the air hole side screwed portion on an outer peripheral surface on one end side in the axial direction.

  According to the said characteristic structure, it fixes to the air hole of a pressure regulator by rotating the main body of a gas leak prevention apparatus. That is, the operator can easily fix the gas leakage prevention device to the pressure regulator. Some pressure regulators are commercially available in which a plug with a hole is fixed to the air hole. In this type of pressure regulator, a screw threaded portion is already provided on the inner peripheral surface of the air hole. . Therefore, even if it is an existing pressure regulator in the gas supply pipe, in some cases, a gas leakage prevention function can be added by fixing the gas leakage prevention device instead of the plug. As described above, it is possible to provide a gas leakage prevention device that is excellent in workability at the time of fixation and can be used for an existing pressure regulator.

  Further, the pressure regulator according to the present invention is characterized in that the main body of the gas leakage prevention apparatus is fixed to the air hole so as to apply an external air pressure to the diaphragm from one end side in the axial direction.

  According to the above-described characteristic configuration, the simple configuration including the cylindrical main body, the spring, the valve seat, and the valve body allows the gas regulator to be used without degrading the function of the pressure regulator in a state where no gas leakage occurs (normal time). A pressure regulator that can prevent leakage can be provided.

Schematic diagram of pressure regulator Sectional drawing of the gas leak prevention apparatus which concerns on 1st Embodiment Cross section of the gas leak prevention device at the start of gas leak Top view of the gas leak prevention device Bottom view of gas leak prevention device Sectional drawing of the gas leak prevention apparatus which concerns on 2nd Embodiment Sectional drawing of the gas leak prevention apparatus which concerns on 3rd Embodiment

[First Embodiment]
Below, the gas leak prevention apparatus 2 and the pressure regulator 1 which concern on 1st Embodiment of this invention are demonstrated using figures.
1. Overview of Pressure Regulator As shown in FIG. 1, the pressure regulator 1 is provided at a predetermined position of the gas flow passage P, and includes a primary side pipe P1 that is upstream of the predetermined position and a secondary side pipe P2 that is downstream. The pressure of the gas G flowing through the secondary side pipe P2 is adjusted by adjusting the opening degree of the valve port 16 to be communicated. Here, a case where city gas flows as gas G in the gas flow path P will be described.

  In the present embodiment, an example in which a so-called governor is used as the pressure regulator 1 will be described. The pressure regulator 1 includes a first diaphragm 12 and a second diaphragm 13 inside. The first diaphragm 12 is configured such that the urging means 14 fixed in the pressure regulator 1 can move in a predetermined direction (vertical direction in the figure) according to the pressure of the gas G in the secondary side pipe P2. . Here, the first diaphragm 12 corresponds to the “diaphragm” in the present invention.

  The first diaphragm 12 is in an airtight state in the pressure regulator 1 in two spaces: a first chamber R1 that communicates with the secondary side pipe P2 and a second chamber R2 that communicates with the outside air via the air holes 10. Divide. As a result, the pressure of the gas G in the first chamber R1 and the external pressure (back pressure) in the second chamber R2 act on the first diaphragm 12 in a direction that cancels each other.

  Here, in addition to the case where the air hole 10 is opened to the atmosphere, there are cases where a gas supply pipe is connected and connected to another pressure regulator (governor). For this reason, the atmospheric pressure or the pressure outside the pressure regulator 1 is applied to the second chamber R <b> 2 through the air hole 10.

  In this embodiment, the pressure regulator 1 is arrange | positioned so that the air hole 10 may become a hole penetrated in the perpendicular direction.

  Further, the first diaphragm 12 is connected to a pressure regulating valve 15 for adjusting the opening degree of the valve port 16 through a connecting portion 17. With such a configuration, the first diaphragm 12 operates the pressure regulating valve 15 in a predetermined direction by the differential pressure between the pressure of the gas G in the first chamber R1 and the back pressure in the second chamber R2, and the valve port 16 By adjusting the opening, the pressure of the gas G in the secondary side pipe P2 is regulated.

  Here, the urging force is set so that the urging means 14 can maintain the gas G in the secondary side pipe P2 at a predetermined pressure.

  The second diaphragm 13 in the pressure regulator 1 is provided, for example, to prevent the gas G from leaking into the first chamber R1 from the primary side pipe P1 when the connecting portion 17 is broken. ing. That is, the pressure regulator 1 includes two diaphragms of the first diaphragm 12 and the second diaphragm 13, thereby preventing the pressure regulator 1 from being broken due to gas leakage from the primary side pipe P <b> 1.

  The pressure regulator 1 includes an air hole side screwing portion 11 on the inner peripheral surface of the air hole 10, and the gas leakage prevention device 2 is fixed to the air hole 10. Specifically, a screw hole is provided as the air hole side screwing portion 11. The air hole-side screw threaded portion 11 is provided to fix a plug provided with a through hole through which outside air can flow. In the embodiment, the gas G leaks in place of the plug. A gas leakage prevention device 2 for preventing the problem is fixed.

  In other words, in the present embodiment, the pressure regulator 1 is an existing governor that does not originally have a mechanism for preventing gas leakage caused by damage to the first diaphragm 12, and the gas leakage preventing device 2 is attached later. ing. Below, the gas leak prevention apparatus 2 is demonstrated in detail.

2. Configuration of Gas Leakage Prevention Device 2 As shown in FIG. 2 (a), the gas leak prevention device 2 includes a valve seat 22, a valve body 23, and a spring 24 as main components in a cylindrical main body 20a.

  The main body 20a is configured to allow fluid to flow in the axial direction A. In the present embodiment, the main body 20a is formed in a hollow cylindrical shape. The axial direction A means the axial center direction of the main body 20a or a direction parallel to the axial center.

  The main body 20a includes an outer peripheral surface screwed portion 21 that is engaged with an air hole side screwed portion on the outer peripheral surface of the one end side A1 in the axial direction A. The outer circumferential surface screw threaded portion 21 is configured to be threadedly engaged with an air hole side threaded threaded portion 11 (screw hole) provided in the air hole 10 of the pressure regulator 1, and in this embodiment, a thread is formed. Has been.

  With such a configuration, the main body 20a is fixed to the air hole 10, so that the outside air that enters from the one end side A1 of the main body 20a and exits to the other end side A2 applies an external pressure to the first diaphragm 12 of the pressure regulator 1. . In the present embodiment, the gas leakage prevention device 2 is fixed to the pressure regulator 1, and the axial direction A coincides with the vertical direction.

  The valve seat 22 is an annular member fixed inside the main body 20a. The valve seat 22 is provided with a through hole in the center, and allows the fluid in the axial direction A to flow through the main body 20a.

  In the present embodiment, the valve body 23 is formed in a spherical shape having a diameter larger than the diameter of the through hole of the valve seat 22. The valve body 23 is connected to one end A1 end of the spring 24 and is configured to be swingable in the axial direction A within the main body 20a. The valve body 23 is provided on the one end side A1 with respect to the valve seat 22, and shuts off the fluid flow inside the main body 20a by contacting the valve seat 22 from the one end side A1.

  The spring 24 is provided so as to bias the valve body 23 toward the other end A2 in a state where the gas leak prevention device 2 is attached to the pressure regulator 1 and no gas leak occurs (normal time). Specifically, it is arranged so as to be inserted into the through hole of the valve seat 22, the valve body 23 is fixed to one end side A <b> 1, and the other end side A <b> 2 is arranged in the axial direction A in the gas leakage prevention device 2. The fixing member 34 of the position variable mechanism 3a whose position is arbitrarily determined is fixed.

  In the present embodiment, the restricting portion 25 is provided on the one end side A1 from the valve body 23. As shown in FIG. 5, the restricting portion 25 is an annular structure having a circular hole larger than the diameter of the valve element 23, and is provided in a cross shape so as to go from the annular structure toward the center. It has a cross-linked structure. This bridging structure has a structure in which the central portion is missing to the extent that the valve body 23 does not come out of the main body 20a.

  The restricting portion 25 restricts the movement of the valve body 23 from the restricting portion 25 to the one end A1 without hindering the flow of the fluid in the axial direction A within the main body 20a.

3. Structure of Spring 24 The natural length L and the spring constant of the spring 24 are set so as to satisfy the following two conditions. The first condition is normally configured such that the sum of the gravity of the valve body 23 and the elastic force of the spring 24 is directed to at least one end A1 when the valve body 23 is in contact with the valve seat 22. Is Rukoto. The second condition is that gravity of the valve body 23, elastic force of the spring 24, and gas leakage occur in a state where the valve body 23 is in contact with the valve seat 22 when a possibility of gas leakage occurs in the pressure regulator 1. Therefore, the sum of the pressure applied to the valve body 23 is at least toward the other end A2.

  When the air hole 10 is provided in the vertical direction and the main body 20a of the gas leakage prevention device 2 fixed to the air hole 10 is in the vertical direction as shown in FIG. Is set to a length L1 which is longer than the natural length L in normal times. That is, the spring 24 is extended in a normal state, and the elastic force toward the other end A2 acts on the valve body 23.

  Here, a force that is pulled to one end A <b> 1 by the dead weight of the valve body 23 acts on the spring 24.

  That is, the spring 24 is configured such that the normal length L1 is such that the position of the valve body 23 is closer to the one end side A1 than the valve seat 22. Further, the normal elastic force of the spring 24 is set to be equal to or smaller than the force (gravity) acting on the spring 24 due to its own weight.

  In the present embodiment, in the normal length L1, the magnitude of the elastic force toward the other end A2 of the spring 24 and the magnitude of the gravity toward the one end A1 by the valve body 23 are configured to be equal. .

  With such a configuration, the valve body 23 can be separated from the valve seat 22 in a normal state. Further, when the possibility of gas leakage occurs due to the damage of the first diaphragm 12, etc., as shown in FIG. 3, the gas G flows from one end side A1 of the main body 20a. It is pushed to the A2 side and can come into contact with the valve seat 22.

  Note that the spring constant of the spring 24 and the normal length L1 (that is, the normal elastic force) are such that the valve element 23 is moved to the other end A2 by the inflow of the gas G when the possibility of gas leakage occurs. It is good to set so that the valve body 23 may contact | abut to the valve seat 22 with the force pressed.

  Further, when the valve body 23 is configured to contact the valve seat 22 in a state where the length L1 of the spring 24 is equal to or longer than the natural length L, when the valve body 23 approaches the valve seat 22, This is preferable because no elastic force is generated on the one end side A1. In the present embodiment, as shown in FIG. 3, the valve seat 22 is configured to contact the valve body 23 in a state where the length L1 of the spring 24 matches the natural length L.

  Here, in this embodiment, in order to ensure the versatility of the gas leakage prevention device 2 so that one gas leakage prevention device 2 can be used for a plurality of types of pressure regulators 1, A position variable mechanism 3a for adjusting the elastic force is provided. Below, the position variable mechanism 3a is demonstrated.

4). Configuration of Position Variable Mechanism 3a As shown in FIGS. 2A and 2B, the position variable mechanism 3a is provided on the other end A2 side of the valve seat 22 in the main body 20a, and the other end of the spring 24 is provided. The position of the fixing member 34 to which the side A2 end is fixed is configured to be adjustable.

  Specifically, the position variable mechanism 3a includes a position fixing portion 31a fixed to the main body 20a, a screw 33, and a fixing member 34 as main components.

  The position fixing portion 31a is provided in a state of being fixed to the other end side A2 side of the valve seat 22. In this embodiment, it is fixed to the other end A2 end of the main body 20a.

  As shown in FIG. 4, the position fixing portion 31 a is an annular structure having a circular hole larger than the diameter of the valve body 23, and is provided in a cross shape so as to go from the annular structure toward the center. Having a crosslinked structure. Thus, the position fixing part 31a is formed so as not to hinder the flow of the fluid in the axial direction A within the main body 20a.

  A screw hole is provided as a screw threaded portion 32 at the center of the position fixing portion 31a. A screw 33 is screwed into the screw threaded portion 32 so that the head of the screw is at the other end A2.

  A fixing member 34 is fixed to one end A <b> 1 of the screw 33. The other end side A <b> 2 of the spring 24 is fixed to the fixing member 34. The fixing member 34 may have any shape as long as it does not block the flow of fluid in the main body 20a and can fix the other end A2 end of the spring 24. In the present embodiment, a cube-shaped member having sides having substantially the same size as the diameter of the screw 33 is used.

  With such a configuration, when the operator fixes the gas leakage prevention device 2 to the pressure regulator 1, only by rotating the screw 33, as shown in FIGS. The position of the screw 33 with respect to 32 moves up and down in the axial direction A, and the position of the fixing member 34 in the axial direction A moves up and down in conjunction. Therefore, since the position of the other end A2 of the spring 24 fixed to the fixing member 34 changes, the elastic force generated by the spring 24 can be adjusted according to the weight of the valve body 23 and the like.

  With the above configuration, the pressure regulator 1 provided with the gas leakage prevention device 2 can prevent the gas G from leaking into the first chamber R1 from the primary side pipe P1 by the second diaphragm 13, and further, Gas leakage from the air hole 10 due to damage to the first diaphragm 12 or the like can be prevented.

[Second Embodiment]
A gas leakage prevention apparatus 2 according to a second embodiment of the present invention will be described with reference to FIGS. 6 (a) and 6 (b). The gas leakage prevention device 2 according to this embodiment is different from the above embodiment in the structure of the “position variable mechanism”. Since the configuration other than the “position variable mechanism” is substantially the same as that of the first embodiment, the description thereof is basically omitted.

  In the present embodiment, the position variable mechanism 3b includes a cylindrical screw 35 that is relatively movable in the axial direction A with respect to the cylindrical main body 20b, so that the shaft on the other end side A2 of the spring 24 is provided. The position in the direction A can be adjusted.

  The main body 20b includes a main body side screwing portion 26 on the other end side A2 from the valve seat 22. As the main body side screwing portion 26, a thread or a screw groove configured to be screwed with a variable portion side screwing portion 36 provided in the screwing body 35 can be used.

  In the present embodiment, a thread groove is provided as the body-side screw threaded portion 26 on the inner peripheral surface of the body 20b.

  On the other hand, the variable position mechanism 3b includes a cylindrical screw 35 and a screw fixing portion 31b. The threaded body 35 is provided with a variable portion side screw threaded portion 36 for being threadedly engaged with the main body side threaded threaded portion 26 on one end side A1 side.

  In the present embodiment, a thread corresponding to the thread groove of the main body side screwing portion 26 is provided on the outer peripheral surface of the one end side A1 of the screwing body 35 as the variable portion side screwing portion 36.

  The screwed body fixing portion 31b is a member that is fixed inside the screwed body 35, and is configured not to block the flow of fluid in the axial direction A in the gas leakage preventing apparatus 2. The shape of the screw fixing part 31b is the same as that of the position fixing part 31a shown in FIG. 4 except that the screw fixing part 32 is not provided.

  In this embodiment, the screw body fixing portion 31b is provided at the other end A2 end portion of the screw body 35. The other end side A2 of the spring 24 is fixed to the center portion of the screw body fixing portion 31b.

  With such a configuration, when fixing the gas leakage prevention device 2 to the pressure regulator 1, the operator simply rotates the screw 35 directly as shown in FIGS. 6 (a) and 6 (b). Since the position of the other end A2 of the spring 24 fixed to the combined fixing portion 31b changes, the elastic force generated by the spring 24 can be adjusted according to the weight of the valve body 23 and the like.

[Third Embodiment]
A gas leakage prevention device 2 according to a third embodiment of the present invention will be described with reference to FIGS. 7 (a) and 7 (b). The gas leakage prevention device 2 according to the present embodiment is different from the above embodiment in “the state of the spring 24 in a normal state”. The configuration other than “the state of the spring 24 in the normal state” is the same as that of the first embodiment, and thus the description thereof is omitted.

  When the gas leakage prevention device 2 is disposed horizontally, the gravity of the valve element 23 does not act in the axial direction A (the force acting in the axial direction A by the gravity of the valve element 23 becomes zero).

  For this reason, the natural length L and the spring constant of the spring 24 are set so as to satisfy the following two conditions. The first condition is that, in a normal state, the elastic force of the spring 24 is configured to be directed to at least one end A1 in a state where the valve body 23 is in contact with the valve seat 22. The second condition is that, when a gas leak may occur in the pressure regulator 1, the valve body 23 is applied to the valve body 23 due to the elastic force of the spring 24 and the gas leak when the valve body 23 is in contact with the valve seat 22. The sum with the pressure is at least toward the other end A2.

  In the present embodiment, as shown in FIG. 7A, the spring 24 has the valve body 23 in a state where the gas leakage prevention device 2 is attached to the pressure regulator 1 and no gas leakage occurs (normal time). It is provided so as to be urged from the other end side A2 to the one end side A1.

  Specifically, the spring 24 is set so that the normal length L1 in the normal time is shorter than the natural length L. That is, the spring 24 is contracted in a normal state, and an elastic force toward the one end A1 side acts on the valve body 23.

  For this reason, this embodiment can be suitably used when the axial direction A of the gas leakage preventing apparatus 2 is fixed so as to coincide with the horizontal direction. This is because in such a case, the gravity of the valve body 23 acts only in the direction perpendicular to the axial direction A, and no pressing force is generated in the direction of the one end A1.

  In this embodiment, as shown in FIG. 7B, when the possibility of gas leakage occurs, the force by which the spring 24 pushes the valve body 23 toward the one end A1 is changed from the one end A1 to the other end. It is necessary to set the normal elastic force (normal length L1) and the spring constant of the spring 24 so that the gas G traveling toward the side A2 becomes smaller than the force pushing the valve body 23.

  With such a configuration, the valve element 23 is urged toward the one end A1 by the spring 24. For example, the axial direction A of the gas leakage prevention device 2 is fixed so as to coincide with the horizontal direction, and gas leakage occurs. Even when the force toward the one end side A1 does not act on the valve body 23 in a non-operating state (normal time), the valve body 23 can be separated from the valve seat 22. That is, the degree of freedom at the time of fixing to the pressure regulator 1 can be increased, and the gas leak prevention device 2 excellent in convenience can be provided.

[Another embodiment]
(1) In the above embodiment, an example in which the main body 20a (20b) is formed in a cylindrical shape, the valve seat 22 is formed in an annular shape, and the valve body 23 is formed in a spherical shape is shown. 22 and the valve body 23 may have any shape as long as the flow of the gas G in the axial direction A in the main body 20a (20b) can be cut off while the valve body 23 is in contact with the valve seat 22.

  For example, the main body 20a (20b) may be a hollow rectangular parallelepiped, the valve seat 22 may be formed in a square shape, and the valve body 23 may be formed in a rectangular parallelepiped. Further, the position of the through hole in the valve seat 22 is not necessarily provided at the center.

(2) In the above embodiment, the example in which the position variable mechanism 3a (3b) is realized by screwing with a screw has been shown. However, if the mechanism can adjust the position in the axial direction A, the screw is used. Means other than screwing may be used.

(3) The position variable mechanism 3a in the first embodiment may be combined with the position variable mechanism 3b in the second embodiment. That is, the gas leakage prevention device 2 includes the main body 20b and the screwed body 35 in the second embodiment, and the screwed body fixing portion 31b of the screwed body 35 includes the position fixing portion 31a and the screw screwed portion 32 in the first embodiment. The screw 33 and the fixing member 34 may be replaced.

(4) In the above embodiment, an example in which the gas leakage prevention device 2 separate from the pressure regulator 1 is fixed to the air hole 10 of the pressure regulator 1 is shown. You may comprise the leak prevention apparatus 2 as integral.

(5) In the above-described embodiment, the pressure regulator 1 has an example in which the two diaphragms of the first diaphragm 12 and the second diaphragm 13 are provided. However, a configuration without the second diaphragm 13 may be used. Absent.

(6) In the above embodiment, an example in which the spring 24 is arranged on the other end side A2 of the valve body 23 has been shown. However, the spring 24 may be arranged on the one end side A1 side of the valve body 23. I do not care. That is, the other end A2 side of the spring 24 may be fixed to the valve body 23 and the one end A1 end may be fixed to the restricting portion 25. In this case, the structure of the restricting portion 25 is changed to a position fixing portion 31a (position variable mechanism 3a) or a screwed body fixing portion 31b (position) so that the position in the axial direction A of the one end A1 end of the spring 24 can be changed. You may comprise like the variable mechanism 3b).

1: Pressure regulator 2: Gas leakage prevention device 3a: Position variable mechanism 3b: Position variable mechanism 10: Air hole 11: Air hole side screwing part 12: 1st diaphragm (diaphragm)
20a: Main body 20b: Main body 22: Valve seat 23: Valve body 24: Spring 25: Restricting portion 26: Main body side screw screwing portion 31a: Position fixing portion 31b: Screw fixing portion 32: Screw screwing portion 33: Screw 34 : Fixing member 35: Screwed body 36: Variable part side screwed part A: Axial direction A1: One end side A2: Other end side G: Gas P: Gas flow passage P1: Primary side pipe P2: Secondary side pipe

Claims (6)

After adjusting the pressure of the gas supplied from the primary pipe upstream from the predetermined position, using an external pressure applied to the diaphragm via the air hole, provided at a predetermined position of the gas flow path, A gas leakage prevention device for preventing gas leakage in a pressure regulator supplied to a secondary pipe downstream from the predetermined position,
A cylindrical main body configured to allow fluid to flow axially therein;
A valve seat provided inside the main body;
A valve body that is in contact with the valve seat from one end side in the axial direction and is provided so as to be able to block the flow of fluid inside the main body;
A spring for urging the valve body in the axial direction,
The body is fixed to the air hole so as to apply an external pressure to the diaphragm from the other end side in the axial direction toward the one end side,
When there is no possibility of gas leakage in the pressure regulator, the sum of the gravity of the valve body and the elastic force of the spring is at least one end in the axial direction when the valve body is in contact with the valve seat. Head to the side
The pressure applied to the valve body due to the gravity of the valve body, the elastic force of the spring, and the gas leakage in a state where the valve body is in contact with the valve seat when a gas leak may occur in the pressure regulator. The gas leakage prevention device is configured so that the sum of the two points at least toward the other end side in the axial direction. The body is
A position variable mechanism configured to variably change the position in the axial direction on the other end side in the axial direction from the valve seat;
A regulating portion for regulating movement of the valve body from the other end side in the axial direction to the one end side on the one end side in the axial direction from the valve body, and the one end side in the axial direction of the spring includes the Fixed to the disc,
The gas leakage prevention device according to claim 1, wherein the other end side of the spring in the axial direction is fixed to the position variable mechanism. The position variable mechanism is
A position fixing portion fixed to the main body;
A screw threaded portion provided in the position fixing portion;
A screw screwed into the screw threaded portion;
A fixing member fixed to one end of the screw in the axial direction,
The gas leakage prevention device according to claim 2, wherein the other end side of the spring in the axial direction is fixed to the fixing member. The body is
Provided with a body-side screw threaded portion on the other end side in the axial direction,
The position variable mechanism is
A cylindrical threaded body provided with a variable part side screw threaded part that is threadedly engaged with the main body side threaded thread part;
A screwed body fixing portion fixed inside the screwed body,
The other end of the spring is
The gas leakage prevention device according to claim 2, wherein the gas leakage prevention device is fixed to the screwed body fixing portion of the position variable mechanism. The pressure regulator includes an air hole side screwed portion on an inner peripheral surface of the air hole;
The gas leakage prevention according to any one of claims 1 to 4, wherein the main body includes an outer peripheral surface screwed portion that engages with the air hole side screwed portion on an outer peripheral surface on one end side in the axial direction. apparatus.   The pressure regulator which was fixed to the said air hole so that the said main body in the gas leak prevention apparatus as described in any one of Claims 1-5 may apply external air pressure to the said diaphragm from the said one end side of the said axial direction.

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