JP2011256921A - Safety valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safety valve capable of easily remarkably changing a spring load of an operation spring from a high-pressure side to a low-pressure side and vice versa with a simple structure.SOLUTION: This safety valve 1 includes: a valve casing 10 including two opening parts 13, 15; a diaphragm 2 for partitioning the inside of the valve casing 10 into a primary chamber 14 and a secondary chamber 16; a diaphragm holder 3 connected to the diaphragm 2; a valve hole 34 for making the primary chamber 14 communicate with the secondary chamber 16; a valve element 5 capable of opening/closing the valve hole 34; and an operation spring 4 received by the diaphragm holder 3 to energize the diaphragm 2, and setting pressure at which the diaphragm 2 reacts with excessive pressure in the primary chamber 14 to open the valve element 5. The valve casing 10 comprises a diaphragm case 11 for housing the diaphragm 2 therein, and a spring case 12 for housing the operation spring 4 therein to support an end of the operation spring 4 serving as a supporting point side, wherein the spring case 12 is screwed and connected to the diaphragm case 11 movably in a spring pressure direction of the operation spring 4.

Description

  The present invention relates to a safety valve attached to a fluid pipe or the like of a hot water device.

  Conventionally, there is a relief valve disclosed in Patent Document 1 as this type of safety valve. As shown in FIGS. 9 and 10, the relief valve 100 includes a valve box 101 having a connection port 110 connected to a pipe such as a water heater and a drain port 111 opened to the atmosphere, and drainage in the valve box 101. The valve body 121 which opens and closes the relief port 113 connected with the opening | mouth 111, the diaphragm 102 which provided the valve body 121, and the action | operation spring 104 which urges | biases the diaphragm 102 in the valve closing direction of the valve body 121 are provided. The operating spring 104 is accommodated in a spring case 114 assembled to the upper end of the valve box 101, and one end on the fulcrum side is supported by a spring support seat 140 of the operating member 106 disposed on the upper end of the spring case 114, The other end is received by a diaphragm presser 103 provided on the upper surface of the diaphragm 102. The operating member 106 is supported so as to be movable with respect to an adjustment screw 105 in which a screw portion 105a is screwed and fixed to an upper screw groove 114a in the spring case 114. Further, a block 170 having a pressurizing chamber K is assembled to the upper end of the spring case 114, and a driving member D that moves due to tap water pressure abuts the upper surface of the operating member 106 in the pressurizing chamber K. Is provided.

  According to the relief valve 100, in the state where tap water is not introduced into the pressurizing chamber K, the spring support seat 140 of the operating member 106 is adjusted by the spring pressure of the operating spring 104 as shown in FIG. Therefore, the spring load of the operating spring 104 is set to the pressure (on the low pressure side) by the adjustment screw 105. On the other hand, as shown in FIG. 10, when the tap water is introduced into the pressurizing chamber K and the drive member D is lowered by the tap water pressure, the actuating member 106 is lowered and the actuating spring 104 is compressed. The spring load 104 is set to a higher pressure side than the pressure (low pressure side) set by the adjusting screw 105.

Japanese Patent Laid-Open No. 6-259142

  The conventional relief valve 100 can change the spring load of the operating spring 104 between the high pressure side and the low pressure side as described above. For this purpose, a block 170 in which a pressurizing chamber K is formed is provided, or an additional pressure is applied. The structure is complicated, for example, it is necessary to provide a mechanism for introducing tap water into the pressure chamber K. In addition, since the spring load of the operating spring 104 on the high pressure side depends on the tap water pressure, the spring load cannot be changed significantly. Although it is conceivable to change the spring load of the operating spring 104 by adjusting the screwing amount of the adjusting screw 105 in the spring case 114, the adjusting screw 105 is rotated when the relief valve 100 is assembled. Since the spring load of the spring 104 is set and the set pressure is fixed after assembly, it is difficult to adjust the spring load of the operating spring 104 with the adjusting screw 105 in the relief valve 100 after assembly (Patent Literature). 1 paragraph 0003).

  This invention is made | formed in view of the said situation, and makes it a subject to provide the safety valve which can change the spring load of an action | operation spring easily to a high voltage | pressure side and a low voltage | pressure side easily with a simple structure.

The safety valve according to the present invention is:
A valve box with two mouths;
A diaphragm that divides the inside of the valve box into a primary chamber that communicates with the first port and a secondary chamber that communicates with the second port;
A diaphragm holder provided on the diaphragm;
A valve hole communicating the primary chamber and the secondary chamber;
A valve body provided on the diaphragm to open and close the valve hole;
An operating spring that is received by the diaphragm holder and urges the diaphragm to set the pressure at which the diaphragm is actuated by the pressure rise in the primary chamber and the valve body opens,
The valve box is composed of a diaphragm case that accommodates the diaphragm, and a spring case that accommodates the operating spring and supports the end on the fulcrum side of the operating spring,
The spring case is screwed to the diaphragm case so as to be movable in the spring pressure direction of the operating spring.

  With the above configuration, the operating spring is expanded or contracted according to the amount of movement of the spring case by moving the spring case that houses the operating spring with respect to the diaphragm case. For example, when the spring case is rotated and moved so as to be higher than the diaphragm case, the operating spring is extended by its own spring pressure according to the amount of movement of the spring case. As a result, the spring load of the operating spring acting on the diaphragm becomes weak, and the pressure can be set on the low pressure side. On the other hand, when the spring case is rotated and moved so as to be lower than the diaphragm case, the operating spring is compressed by the spring case according to the amount of movement of the spring case. As a result, the spring load of the operating spring acting on the diaphragm is increased, and the pressure can be set on the high pressure side. As described above, even after the safety valve is assembled, the spring load of the operating spring acting on the diaphragm can be easily set to the low pressure side and the high pressure side by a simple operation of simply rotating the spring case. Moreover, the spring load of the operating spring can be significantly changed from the low pressure side to the high pressure side according to the amount of movement of the spring case.

In the above safety valve,
A valve rod that extends from the valve body arranged on the primary chamber side and passes through a guide hole formed through the diaphragm presser and projects to the secondary chamber side;
A valve spring that is extrapolated to the arrangement portion of the valve stem on the secondary chamber side and biases the valve body in the valve-closing direction;
A pressure regulating shaft facing the end of the valve stem on the secondary chamber side and disposed at a predetermined interval from the end of the valve stem;
A pressure adjusting portion that is provided in the spring case and accommodates the pressure adjusting shaft;
It is desirable that the pressure adjusting portion is screwed and connected to the spring case so that the pressure adjusting shaft can move in a direction in which the pressure adjusting shaft approaches or separates from the end of the valve rod.

  In the above safety valve, when the diaphragm is displaced to the secondary chamber side against the spring pressure of the operating spring due to the pressure increase on the primary chamber side, and the valve stem of the valve body contacts the pressure adjusting shaft, the displacement of the diaphragm further The valve body is opened. Thereby, the excess pressure on the primary chamber side is released to the secondary chamber side through the valve hole, and the pressure increase on the primary chamber side is eliminated. On the other hand, when the primary chamber side becomes negative pressure, the valve element is opened against the spring pressure of the valve spring through the valve hole by the pressure (atmospheric pressure) of the secondary chamber. Thereby, atmospheric pressure is attracted | sucked from a secondary chamber to a primary chamber through a valve hole, and the negative pressure by the side of a primary chamber is eliminated. If the spring case is moved with respect to the diaphragm case in order to change the spring load of the operating spring in such a safety valve, the pressure adjusting unit moves together with the spring case, and the distance between the pressure adjusting shaft and the valve stem is changed. .

  However, according to the above configuration, the pressure adjusting unit is screwed to the spring case so that the pressure adjusting shaft can be adjusted to the end of the valve rod so that the spring case is higher than the diaphragm case. When moved in such a manner, the pressure adjusting unit can be rotated and moved so as to be lower than the spring case by the amount of movement of the spring case. Further, when the spring case is moved so as to be lower than the diaphragm case, the pressure adjusting unit can be rotated and moved so as to be higher than the spring case by the amount of movement of the spring case.

  Thus, by making the pressure adjusting part movable with respect to the spring case, the distance between the valve stem and the pressure adjusting shaft can be kept the same before and after the movement of the spring case. Therefore, the pressure settings on the low pressure side and the high pressure side at which the valve element opens can be set according to the amount of movement of the spring case only. Further, the height of the pressure adjusting portion can be kept the same as that of the diaphragm case before and after the movement of the spring case. Accordingly, the height of the safety valve can be maintained at the same height before and after the movement of the spring case, and there is no inconvenience such as interference with the peripheral portion. Furthermore, since the setting of the pressure at which the valve element opens due to the excess pressure in the primary chamber can be adjusted also by the movement of the pressure adjusting unit, the pressure setting can be significantly changed from the low pressure side to the high pressure side.

In the above safety valve,
It is desirable that the pressure adjusting shaft is screwed and connected so that the distance between the pressure adjusting shaft and the end of the valve rod can be adjusted.

  According to this, the pressure adjusting shaft can be rotated and moved in accordance with the amount of movement of the spring case to adjust the distance from the end of the valve stem. Can be kept the same. Therefore, the pressure settings on the low pressure side and the high pressure side at which the valve element opens can be set according to the amount of movement of the spring case only. Furthermore, since the setting of the pressure at which the valve element opens due to the excess pressure in the primary chamber can be adjusted by the movement of the pressure adjusting shaft, the pressure setting can be significantly changed from the low pressure side to the high pressure side.

  As described above, according to the present invention, the spring load of the operating spring can be easily set to the low pressure side and the high pressure side by simply rotating and moving the spring case even after the safety valve is assembled, The spring load of the operating spring can be significantly changed from the low pressure side to the high pressure side according to the amount of movement of the spring case.

It is sectional drawing which shows the valve closing state of the safety valve by embodiment. It is a top view which shows the external appearance of the safety valve by embodiment. It is sectional drawing which shows the forced valve opening state which hold | maintained the manual lever upright. It is sectional drawing which shows the valve opening state at the time of the pressure rise of a primary side. It is sectional drawing which shows the valve opening state at the time of the primary side negative pressure. It is sectional drawing which shows the state which moved the spring case highly and the spring load of the action | operation spring was pressure-set to the low voltage | pressure side. It is sectional drawing which shows the state which moved the spring case low and the spring load of the action | operation spring was set to the high voltage | pressure side. It is sectional drawing which shows the valve closing state of the safety valve by other embodiment. It is sectional drawing which shows the state by which the spring load of the action | operation spring was set to the low pressure side in the conventional relief valve. It is sectional drawing which shows the state by which the spring load of the action | operation spring was set to the high voltage | pressure side in the conventional relief valve.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
As shown in FIG. 1, the safety valve 1 according to the embodiment includes a valve box 10 in which two ports 13 and 15 are formed at right angles, a primary chamber 14 that communicates with the first port 13 in the valve box 10, and a second chamber. A diaphragm 2 that is partitioned into a secondary chamber 16 that communicates with the mouth portion 15 of the first diaphragm 15, a diaphragm retainer 3 that is coupled to the diaphragm 2, and a valve that is formed in the diaphragm retainer 3 and communicates the primary chamber 14 and the secondary chamber 16. The hole 34, the valve body 5 that is disposed on the primary chamber 14 side so that the valve hole 34 can be opened and closed, and the diaphragm 2 is urged toward the primary chamber 14 to increase the pressure in the primary chamber 14 so that the diaphragm 2 responds. And an operating spring 4 for setting the pressure at which the valve body 5 opens.

  The first mouth portion 13 of the valve box 10 is connected to a fluid piping or a fluid container of a hot water device, and the second mouth portion 15 is open to the atmosphere. The valve box 10 includes a diaphragm case 11 that accommodates the diaphragm 2, and a spring case 12 that accommodates the operating spring 4 and supports the end portion on the fulcrum side of the operating spring 4 with the ceiling surface 18. The valve box 10 is made of resin or metal.

  The diaphragm case 11 has an upper part 11A and a lower part 11B, and the upper part 11A and the lower part 11B are assembled so as to sandwich the outer edge part of the diaphragm 2. The diaphragm case 11 in the diaphragm case 11 has a large-diameter portion 17a. The step 17b connected to the large-diameter portion 17a stops the movement of the diaphragm 2 toward the primary chamber 14 at a predetermined position. A plurality of convex portions 17c for projecting are provided on the circumference. A metal annular washer 23 integrally formed on the lower surface of the diaphragm 2 facing the primary chamber 14 is brought into contact with the convex portions 17c.

  The spring case 12 is attached to a coupling port 11x provided in the upper portion 11A of the diaphragm case 11. Screw grooves 12a and 11a are provided in the outer surface of the lower part of the spring case 12 and the coupling opening 11x of the diaphragm case. The spring case 12 is screwed to the diaphragm case 11 so as to be movable in the spring pressure direction of the operating spring 4. It is connected.

  The diaphragm retainer 3 is formed on the upper surface of the diaphragm 2 facing the secondary chamber 16 side. The diaphragm 2 is made of a rubber sheet, and the diaphragm retainer 3 is made of resin. The diaphragm 2 and the diaphragm retainer 3 are configured as one part integrally formed by a two-color molding method of injection molding or the like. On the outer periphery of the diaphragm retainer 3, a concave groove 31 is formed in an annular shape for receiving the end portion on the operating point side of the operating spring 4. 4 is arranged in a compressed state. As a result, the diaphragm 2 is urged toward the primary chamber 14 by the spring pressure of the operating spring 4 in the compressed state. Therefore, by determining the height of the spring case 12 with respect to the diaphragm case 11, the spring load of the operating spring 4 acting on the diaphragm 2 can be set.

  At the center of the diaphragm retainer 3, a cylindrical portion 32 that penetrates the center hole 21 of the diaphragm 2 and projects toward the primary chamber 14 is integrally formed. The cylinder portion 32 has a guide hole 33 provided in the center portion and a plurality of valve holes 34 provided around the guide hole 33. A guide cylinder 35 that protrudes toward the secondary chamber 16 so as to extend the guide hole 33 is integrally formed in the cylinder portion 32. A valve body 5 that allows opening and closing of the plurality of valve holes 34 is disposed on the primary chamber 14 side, and a valve rod 51 extending from the valve body 5 passes through the guide hole 33 and enters the secondary chamber 16. It is protruding. The valve body 5 and the valve stem 51 are constituted by a single resin part formed by integral molding such as injection molding.

  The valve stem 51 is provided with a valve spring 52 that is less elastic than the operating spring 4. One end of the valve spring 52 is received on the outer periphery of the guide cylinder 35, and the other end is located near the upper end of the valve stem 51. It is received by the snap ring 53 fitted. In this way, the valve spring 52 is disposed in a compressed state between the snap ring 53 and the diaphragm retainer 3, and the valve rod 51 is drawn into the secondary chamber 16 side by the spring pressure of the valve spring 52, so that the valve element 5 Is urged in the valve closing direction to close the valve hole 34.

  The valve body 5 includes a disk portion 54 that extends in a direction perpendicular to the axis of the valve stem 51, and a cylindrical peripheral wall portion 55 that protrudes from the outer peripheral end of the disk portion 54 to the opposite side of the diaphragm 2. The distal end 55a of the peripheral wall portion 55 of the valve body 5 is formed to be tapered, and the distal end 55a of the peripheral wall portion 55 is brought into contact with the lower surface of the diaphragm 2 so as to be freely attached and detached. Since the front end 55a of the peripheral wall portion 55 of the valve body 5 is tapered, it can be strongly pressed against the diaphragm 2, and as a result, the sealing performance between the valve body 5 and the diaphragm 2 is improved.

  Further, the inner diameter of the guide hole 33 is set to be substantially the same as the outer diameter of the valve stem 51 (same as or slightly larger than the outer diameter of the valve stem 51). Thereby, the valve stem 51 is inserted and supported straight and stably in the axial direction of the guide hole 33, so that the posture of the valve body 5 formed on the valve stem 51 is not inclined with respect to the diaphragm surface forming the valve seat 22. The sealing performance by the valve body 5 is more stably exhibited by being held in parallel.

  On the upper part of the spring case 12, a pressure adjusting unit 6 is provided. The pressure adjusting unit 6 includes a cylindrical body 61 attached to a connection port 12 x provided on the upper wall of the spring case 12, a pressure adjusting nut 62 slidably accommodated in the cylindrical body 61, and a screw on the pressure adjusting nut 62. A pressure regulating shaft 63 that is connected and protrudes from the through hole 64 at the bottom of the cylindrical body 61 into the secondary chamber 16 is provided. Screw grooves 6 a and 12 b are provided on the outer surface of the lower side wall of the cylinder 61 and the connection port 12 x of the spring case 12, and the cylinder 61 is configured such that the pressure adjusting shaft 63 is the end of the valve stem 51 with respect to the spring case 12. Are screwed together so as to be movable in the direction of approaching and separating.

  The pressure adjusting shaft 63 is slidably inserted into the through hole 64 in a state in which the water tightness of the through hole 64 is secured by the sealing material 65. The pressure adjusting shaft 63 is opposed to the end portion of the valve rod 51 on the secondary chamber 16 side, and is disposed so that the distance from the end portion of the valve rod 51 can be adjusted. A screw groove 63 a is formed on the outer surface of the upper portion of the pressure adjusting shaft 63, and is screwed into the screw groove 62 a of the pressure adjusting nut 62. A ring-shaped pressing plate 66 is attached to the bottom of the cylinder 61, and a pressure adjusting spring 67 is disposed in a compressed state between the pressing plate 66 and an annular recess 62b formed on the lower surface of the pressure adjusting nut 62. ing.

  A recess 61a is continuously formed over the entire outer surface of the upper portion of the cylindrical body 61, and an arm 68 having a U-shaped cross section is attached between the recess 61a and the upper surface of the flange portion 62b formed on the upper portion of the pressure adjusting nut 62. The pressure adjusting shaft 63 and the pressure adjusting nut 62 are held in a retaining state. Referring also to FIG. 2, the upper end portion of arm 68 has a pair of tongue pieces 68a bent upward, and manual lever 7 is attached between these tongue pieces 68a by a split pin 70 so as to be vertically rotatable. It has been.

  The manual lever 7 is normally disposed in a lateral posture orthogonal to the pressure adjusting shaft 63. When the manual lever 7 is rotated upward or downward, an operation piece 71 formed to hang from the front of the manual lever 7. The upper surface of the flange 62b of the pressure adjusting nut 62 is pushed downward. Accordingly, the pressure adjusting shaft 63 moves downward together with the pressure adjusting nut 62 to move the valve rod 51 toward the primary chamber 14, thereby forcibly opening the valve body 5. Then, by releasing the pressing force applied to the pressure adjusting nut 62 by the manual lever 7, the pressure adjusting shaft 63 is retracted by the elastic force of the pressure adjusting spring 67, and the valve body 5 is moved to the diaphragm 2 by the elastic force of the valve spring 52. Sit down and return to the closed state.

  Further, as shown in FIG. 3, if the manual lever 7 is pushed up to stand on the pressure adjusting nut 62 and the pressure adjusting nut 62 is held in the pressed down state, the valve body 5 is forcibly separated from the diaphragm 2 as described above. The valve is kept open. In order to cancel the forced valve opening state, when the manual lever 7 is pushed down to return to the original lateral orientation, the valve body 5 returns to the valve closing state.

  When the manual lever 7 is in the horizontal posture, a tool such as a screwdriver is inserted through an opening 72 formed near the tip of the manual lever 7 and is engaged with a groove 63b provided at the upper end of the pressure adjusting shaft 63. By rotating the shaft 63 and adjusting the screwing amount of the pressure adjusting shaft 63 into the pressure adjusting nut 62, the distance between the pressure adjusting shaft 63 and the valve stem 51 can be adjusted. Accordingly, whether the pressure setting for releasing the excess pressure on the primary side in the piping or the like is set to the high pressure side or the low pressure side can be determined by the spring load by the operating spring 4, but the pressure setting value at that time is regulated. The distance between the lower end of the shaft 63 and the upper end of the valve stem 51 can be adjusted by appropriately approaching or separating.

Next, the operation of the safety valve 1 configured as described above will be described.
Referring to FIG. 1 and FIG. 4, when the internal pressure of the pipe connected to the primary chamber 14 side rises above the set pressure, the diaphragm rises against the spring pressure of the operating spring 4 due to the pressure increase in the primary chamber 14. 2 is displaced to the secondary chamber 16 side. At this time, the valve body 5 also moves together with the diaphragm 2 while being seated on the diaphragm 2 serving as the valve seat 22. When the valve rod 51 integrated with the valve body 5 comes into contact with the pressure adjusting shaft 63, the valve body 5 is separated from the diaphragm 2 and opened by the diaphragm 2 which is further displaced toward the secondary chamber 16. 4), the fluid corresponding to the excess pressure on the primary chamber 14 side is released to the secondary chamber 16 side through the valve hole 34. As a result, when the pressure in the primary chamber 14 drops to a set value, the diaphragm 2 is displaced toward the primary chamber 14 by the spring pressure of the operating spring 4, and the valve body 5 is seated on the diaphragm 2 that becomes the valve seat 22 and is closed. I speak. As described above, an abnormal increase in pressure in the pipe or the like is prevented.

  On the other hand, referring to FIG. 5 together with FIG. 1, when the pressure in the pipe connected to the primary chamber 14 side becomes negative, the pressure in the primary chamber 14 is higher than the atmospheric pressure in the secondary chamber 16 communicating with the outside. Pressure drops (negative pressure). Then, the valve body 5 is pressed toward the primary chamber 14 against the spring pressure of the valve spring 52 by the pressure (atmospheric pressure) of the secondary chamber 16 through the valve hole 34, and the valve body 5 serves as the valve seat 22. And the valve is opened (see FIG. 5), and atmospheric pressure is sucked from the secondary chamber 16 into the primary chamber 14 through the valve hole 34. As a result, when the negative pressure in the piping or the like is eliminated and the pressure in the primary chamber 14 rises to a set value, the valve body 5 is seated on the diaphragm 2 serving as the valve seat 22 by the spring pressure of the valve spring 52 and the valve is closed. To do. As a result, negative pressure in the pipe or the like is prevented. In this way, it is possible to quickly return to the set pressure not only when the pressure in the primary side pipe or the like abnormally increases but also when the pressure becomes negative.

  By the way, the spring case 12 is screwed and connected to the diaphragm case 11 by screw grooves 11a and 12a so as to be movable in the spring pressure direction of the operating spring 4. Accordingly, the operating spring 4 is expanded and contracted according to the amount of movement of the spring case 12 by moving the spring case 12 that houses the operating spring 4 with respect to the diaphragm case 11.

  As shown in FIG. 6, for example, when the spring case 12 is rotated and moved so as to be higher than the diaphragm case 11, the operating spring 4 is extended by its own spring pressure according to the amount of movement of the spring case 12. As a result, the spring load of the operating spring 4 acting on the diaphragm 2 becomes weak, and the pressure on the low pressure side can be set. On the other hand, as shown in FIG. 7, when the spring case 12 is rotated and moved so as to be lower than the diaphragm case 11, the operating spring 4 is compressed by the spring case 12 according to the amount of movement of the spring case 12. As a result, the spring load of the operating spring 4 acting on the diaphragm 2 is increased, and the pressure can be set on the high pressure side.

  As described above, even after the safety valve 1 is assembled, the spring load of the operating spring 4 acting on the diaphragm 2 can be easily set to the low pressure side and the high pressure side by a simple operation of simply rotating the spring case 12. . Moreover, the spring load of the operating spring 4 can be significantly changed from the low pressure side to the high pressure side according to the amount of movement of the spring case 12.

  Here, when the spring case 12 is moved with respect to the diaphragm case 11 in order to change the spring load of the operating spring 4 in the safety valve 1, the pressure adjusting unit 6 is moved together with the spring case 12, and the pressure adjusting shaft 63 and the valve stem 51 are moved. The interval between and will be changed. However, in the pressure adjusting unit 6, the pressure adjusting shaft 63 is screwed and connected to the spring case 12 by screw grooves 6 a and 12 a so that the distance from the end of the valve rod 51 can be adjusted. Therefore, when the spring case 12 is moved so as to be higher than the diaphragm case 11, the pressure adjusting unit 6 is rotated so as to be lowered relative to the spring case 12 by the amount of movement of the spring case 12. Yes (see FIG. 6). Further, when the spring case 12 is moved so as to be lower than the diaphragm case 11, the pressure adjusting unit 6 is rotated and moved so as to be higher than the spring case 12 by the amount of movement of the spring case 12. Yes (see FIG. 7).

  Thus, by making the pressure adjusting unit 6 movable with respect to the spring case 12, the distance between the valve stem 51 and the pressure adjusting shaft 63 can be kept the same before and after the movement of the spring case 12. Accordingly, the pressure settings on the low pressure side and the high pressure side at which the valve body 5 opens can be set according to the amount of movement of the spring case 12 only. In addition, the height of the pressure adjusting unit 6 can be maintained at the same height with respect to the diaphragm case 11 before and after the movement of the spring case 12. Therefore, the height of the safety valve 1 can be maintained at the same height before and after the movement of the spring case 12, and there is no inconvenience such as interference with the peripheral portion.

  Further, since the pressure adjusting shaft 63 is screwed to the pressure adjusting nut 62 so that the interval between the pressure adjusting portion 6 and the end of the valve rod 51 can be adjusted, the pressure adjusting shaft 63 is adjusted according to the amount of movement of the spring case 12. The distance between the valve rod 51 and the end of the valve rod 51 can be adjusted by rotating 63, and the distance between the valve rod 51 and the pressure regulating shaft 63 can be kept the same before and after the movement of the spring case 12. Even in this way, the pressure settings on the low pressure side and the high pressure side at which the valve body 5 opens can be set according to the amount of movement of the spring case 12 only.

  Further, the spring case 12 is moved to change the spring load of the operating spring 4 to the low pressure side or the high pressure side, and the pressure adjusting unit 6 or the pressure adjusting shaft 63 is moved to increase the distance between the valve stem 51 and the pressure adjusting shaft 63. By adjusting, the pressure setting at the time of opening the valve with respect to the excess pressure on the primary chamber 14 side can be changed more greatly from the low pressure side to the high pressure side.

(Other embodiments)
As shown in FIG. 8, other embodiment comprises the safety valve 1X for releasing the excess pressure by the side of the primary chamber 14. As shown in FIG. In the safety valve 1 </ b> X, two openings 13 and 15 are provided in the diaphragm case 11, and an annular convex opening 19 serving as a valve hole is provided in the secondary chamber 16 that communicates with the second opening 15. The valve body 5 that is seated on the annular convex portion 19 and can be opened and closed is integrally formed on the lower surface of the diaphragm 2. The spring case 12 accommodates an operating spring 4 that urges the diaphragm 2 toward the secondary chamber 16, and is screwed and connected to the coupling port 11 x of the diaphragm case 11 by screw grooves 11 a and 12 a. Therefore, also with this safety valve 1X, the spring load of the operating spring 4 can be easily set to the low pressure side and the high pressure side only by rotating and moving the spring case 12, and the amount of movement of the spring case 12 can be increased. Accordingly, the spring load of the operating spring 4 can be significantly changed from the low pressure side to the high pressure side. The safety valve 1X of the other embodiment shown in FIG. 8 is not provided with a pressure adjusting unit, but the part indicated by the same reference numeral in FIG. 1 in FIG. 8 is the safety valve (FIG. 1) of the above embodiment. It is the same as or equivalent to what has been described.

1, 1X Safety valve 2 Diaphragm 3 Diaphragm retainer 4 Actuating spring 5 Valve element 6 Pressure adjusting part 6a, 11a, 12a, 12b Screw groove 7 Manual lever 10 Valve box 11 Diaphragm case 11x Connection port 12 Spring case 12x Joint port 13, 15 Portion 14 Primary chamber 16 Secondary chamber 33 Guide hole 34 Valve hole 51 Valve rod 52 Valve spring 63 Pressure regulating shaft

Claims (3)

A valve box with two mouths;
A diaphragm that divides the inside of the valve box into a primary chamber that communicates with the first port and a secondary chamber that communicates with the second port;
A diaphragm holder provided on the diaphragm;
A valve hole communicating the primary chamber and the secondary chamber;
A valve body provided on the diaphragm to open and close the valve hole;
An operating spring that is received by the diaphragm holder and urges the diaphragm to set the pressure at which the diaphragm is actuated by the pressure rise in the primary chamber and the valve body opens,
The valve box is composed of a diaphragm case that accommodates the diaphragm, and a spring case that accommodates the operating spring and supports the end on the fulcrum side of the operating spring,
The spring case is a safety valve that is screwed to the diaphragm case so as to be movable in the spring pressure direction of the operating spring. The safety valve according to claim 1,
A valve rod that extends from the valve body arranged on the primary chamber side and passes through a guide hole formed through the diaphragm presser and projects to the secondary chamber side;
A valve spring that is extrapolated to the arrangement portion of the valve stem on the secondary chamber side and biases the valve body in the valve-closing direction;
A pressure regulating shaft facing the end of the valve stem on the secondary chamber side and disposed at a predetermined interval from the end of the valve stem;
A pressure adjusting portion that is provided in the spring case and accommodates the pressure adjusting shaft;
The pressure adjusting unit is a safety valve that is screw-connected to the spring case so that the pressure adjusting shaft can move in a direction in which the pressure adjusting shaft approaches or separates from the end of the valve rod. The safety valve according to claim 2,
The pressure adjusting shaft is a safety valve that is screwed and connected so that the distance between the pressure adjusting portion and the end of the valve stem can be adjusted.

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