JP2784379B2 - Pressure reducing valve - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas pressure reducing valve, and more particularly to a gas pressure reducing valve which is used at a small set secondary pressure and a small flow rate, and is set even during restart and long-term operation. The present invention relates to a pressure reducing valve having a stable secondary pressure.

[Conventional technology]

As the gas pressure reducing valve, for example, those described in Japanese Utility Model Laid-Open No. 61-99211, Japanese Patent Application Laid-Open No. 58-29020, Japanese Utility Model Laid-Open No. 61-70212, and the like are known.

Such a pressure reducing valve does not use a lubricant in the flow path and has a non-relief mechanism. The reason is as follows.

Although lubricants are chemically stable at very low vapor pressures, very low vapor pressure lubricants may not be admixed depending on the gas being handled. Even if forgiven, it sometimes happens that the deposition of lubricant on downstream, for example flow resistance tubes or constrictions, impairs the function of those parts. Also, although chemically stable, the chemical action of lubricants and gases over long periods of time
The lubricant may harden or deteriorate slightly, which may significantly impair the stability of the set secondary pressure.

The non-relief mechanism is a mechanism necessary for avoiding that the dissipation of gas becomes a problem in terms of increasing gas consumption and that the toxicity of gas does not affect the surroundings.

Regarding the point of gas dissipation, when the pressure detecting element is a membrane-like product such as a rubber diaphragm, for example, the gas component selectively moves and the composition changes,
It occurs especially when the flow rate is very small. In such a case,
Generally, a metal bellows or a metal diaphragm is used as the pressure detecting element.

[Problems to be solved by the invention]

However, in the above prior art, for example, 5 to 50 kP
Set the secondary pressure to about a and apply the JIS C 0041 Environmental Test Method (Electrical / Electronic) Impact Test Method "Basic test for robustness, handling and transportation. Permanently installed on the ground or durable impact resistant packaging. 147m / S ₂ , applied to products transported by road, rail or air
If an impact time of 11 ms and a half sine wave is applied, the set secondary pressure will fluctuate significantly.

This variation is caused by, firstly, the transmission rod being displaced in the direction perpendicular to the axial force with respect to the spherical valve, and the positional relationship between the valve spring and the spherical valve being displaced in the perpendicular direction. This is because a difference occurs in the pressing force of the spherical valve against the valve seat, the sealing circle of the valve seat and the sealing circle of the spherical valve are not coaxial, and the same gap is not maintained. In the present specification, this development is referred to as a first dance phenomenon. Note that the sealing circle refers to a virtual circle formed at a circumferential contact position between the valve seat and the spherical valve when they are in a sealed state.

Second, the central axis of the transmission rod moves in the direction perpendicular to it, or the axial force, which is the resultant force of the compensating spring and the bellows, has a component force in the direction perpendicular to it, and the point of action of the central axis of the transmission rod and the axial force This is because the trajectory does not match. Here, this phenomenon is referred to as a second jump phenomenon.

In addition, for example, the frequency range applied to “equipment installed or transported on ships, railways and land vehicles” according to the JIS (0040 environmental test method (electric / electronic) sine wave vibration test method)
If a vibration of 10 to 50 Hz and an acceleration of 19.6 m / S ₂ is applied, the set secondary pressure fluctuates significantly.

This is because the valve spring and / or the compensating spring resonate, and at this time, the amount of deflection is changed due to the addition of the rotation axis and the like. Here, this phenomenon is called the third dance phenomenon.

The phenomena described separately for these various tests naturally occur even when combined.

An object of the present invention is to provide a pressure reducing valve having a mechanism capable of suppressing the occurrence of each of the above phenomena and stably maintaining a secondary pressure once set.

[Means for solving the problem]

In order to achieve the above object, the present invention has a valve seat member having a straight through hole and disposed between a primary pressure side and a secondary pressure side, and is disposed on a primary side with respect to the valve seat member. A movable valve,
In the pressure reducing valve including a bellows having a convex portion disposed on the secondary side with respect to the valve seat member and a transmission rod fixed to the bottom of the convex portion and transmitting the movement of the convex portion to the movable valve, A guide portion that extends in a direction parallel to the through hole and linearly moves the convex portion only in the parallel direction is formed on the bellows side of the valve seat member, and the transmission rod is slid linearly along the straight through hole. The present invention proposes a pressure reducing valve that moves the movable valve while keeping it coaxial with the valve seat member in accordance with the linear movement of the projection.

[Action]

In this way, the means for restricting the movement of the movable valve is provided so that the sealing circle of the movable valve always keeps the same coaxial gap with the sealing circle of the valve seat over the movable range of the movable valve. Therefore, the displacement of the movable valve can be eliminated, and the fluctuation of the set secondary pressure can be suppressed.

〔Example〕

Next, an embodiment of a pressure reducing valve according to the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing the structure of one embodiment of a pressure reducing valve according to the present invention. The valve element 10 has a primary pressure port 11 on the side and a secondary pressure port 12 on the bottom. The upper surface 13 of the valve body 10 is a reference surface, and a hole 14 is formed vertically in the reference surface 13 and is formed in three steps at the center of the valve body 10. Counterbore 15
Must be exactly parallel to the reference plane,
Must be perpendicular to the reference plane and concentric with the hole 14, the counterbore 17 must be a surface suitable for the O-ring sealing surface, and the counterbore 18 has escaped. Reference numeral 19 denotes a secondary pressure guide path, and reference numeral 20 denotes a discarded hole sealing ball for processing.

FIG. 2 is a cross-sectional view showing around the hole 14 in the embodiment of FIG. The primary pressure conduit 21 communicates with the hole 14 and the groove 22
Thereby, it leads to the counterbore 18.

Returning to FIG. 1, a small-diameter, straight through hole 31 is dug on the central axis of the valve seat plate 30, a lower portion becomes a counterbore 32, and a conduit 323 is dug in the counterbore 32. I have. The guide 34 integral with the valve seat plate 30 is exactly coaxial with the straight through-hole 31 and has an intake hole 35 at its lowermost part. Valve seat plate 30
Is an O-ring whose dimensions, surface roughness, and hardness have been examined. The valve seat plate 30 includes an O-ring 37 and a screw 38.
Therefore, the valve body 10 is fixed to the valve body 10 without any clearance by the counterbore surface 15, and becomes airtight.Moreover, due to the fitting tolerance of the counterbore surface 16, the linear shape of the central axis of the hole 14 of the valve body 10 and the valve seat plate 30. The central axis of the through hole 31 coincides with the error of 10 μm or less, and all the surfaces inside the lower surface of the O-ring valve seat 36 are at the same height from this central axis and within the same distance within the above error. is there.

The transmission rod 41 is fixed to the true spherical valve 40 coaxially with the axis passing through the center thereof. The spherical valve 40 and the hole 14 of the valve body 10
It has a gap of about 15 μm over the operating temperature range, and has a straight through hole 31 between the transmission rod 41 and the valve seat plate 30.
Also have a gap of about 15 μm. A valve spring 45, which is a compression spring that presses the spherical valve 40 against the valve seat 36, has an outer diameter that provides a gap of only about 200 μm on the inner wall of the hole 14, and the seats at both ends force the spherical valve 40 in an oblique direction. , That is, the spherical valve 40 is processed such that a force due to the sealing circle and deflection is applied.

At the center of the bellows 50, a convex portion 51 is formed on the upper surface, and a spring seat 55 to which the upper end of the transmission rod 41 abuts is attached to the lower bottom 52. The gap between the outer diameter of the projection 51 and the inner wall of the guide 34 is about 50 to 500 μm. On the inner wall of the projection 51,
A compensating spring 58, which is a compression spring, includes a spring seat 56 having a recess 57.
And the spring seat 55. The spring seat 55 is
The central axis of the spring 58 is 100 to 500 μ with respect to the central axis of the projection 51.
It is set to match at about m. The bonnet 60 has an intake hole 61, and is fixed to the valve body 10 with a screw 63.
In this case, the bellows 50
The pressure chamber 64 is hermetically sealed from the outside by an O-ring 62.

The secondary pressure adjusting screw 65 has a handle 66 and a bonnet 60
, And fixed by the additional screw 67 so as not to be loosened.
The central axis of the adjusting screw 65 is 100 to 500μ with the central axis of the transmission rod 41.
The values are matched at about m. The tip of the adjusting screw 65 has a hemispherical shape and contacts the concave portion 57 of the spring seat 55. When the adjusting screw 5 is loosened, it separates from the concave portion 57 of the spring seat 56, and the bellows 50 extends almost free length.
Is a spherical valve separated from the transmission rod 41 and pushed up by a valve spring 45.
40 contacts the valve seat 36 along the sealing circle, and the primary pressure side and the pressure chamber 64
And completely isolated.

First, a compressed air source having a gauge pressure of 50 ± 10 kPa is connected to the primary pressure port 11, and a resistance that can be set to a flow rate of 33 ml / min is applied to the secondary pressure port 12. Next, turn the adjusting screw 65 to set the secondary pressure to 20 kP
When the spring 58 is bent so as to be a, the lower bottom 5 of the spring seat 55
2 is pushed downward and pierces the transmission rod 41, so that the spherical valve 40 is kept coaxial so that the sealing circle of the spherical valve 40 always keeps a gap equal to the sealing circle of the valve seat 36. Leaves seat 36. At this time, the sum of the force by which the primary pressure pushes up the spherical valve 40 and the force by which the valve spring 45 pushes up the valve 40, and the force by which the compensation spring 58 pushes down the lower bottom 52 of the spring seat 55 and the secondary pressure by the spring seat 55 Push up the lower bottom 52 (because the bellows 50 extends upwards,
The spring force of the bellows 50 must also be considered) and the difference in forces is balanced via the transmission rod 41. Thereafter, the additional screw 67 is tightened so that the adjusting screw 65 does not move.

Next, when the primary pressure is set to the atmospheric pressure, the secondary pressure is set to the atmospheric pressure, the force of the bellows 50 due to the secondary pressure becomes almost zero, and the spherical valve 40 is further separated from the valve seat 36, and the upper force is applied. The downward force is balanced and stopped. The pressure reducing valve of this embodiment is transported in this state. In each case, a spherical valve
The valve 40 and the valve seat 36 are not sealed. In this state, an impact that does not cause permanent deformation of the member (of course, the above-described JIS test is within this range) is applied. For a force in the lateral direction with respect to the central axis of the transmission rod 41,
The difference between the center of the spherical valve 40 and the center of the valve seat 36 is 25 μm at the maximum, but since the valve 40 is spherical, the transmission rod 41 and the linear through hole 31 of the valve seat plate 30 have a gap of about 15 μm. Will be corrected. Adjusting screw 65 and spring seat 56, spring seat 56 and compensation spring 58,
Compensating spring 58 and spring seat 55, convex portion 51 of spring seat 55 and bellows 50
Deviation of the inner diameter of the valve seat
By 34, only a maximum displacement of 500 μm occurs in the horizontal direction. The impact in the same direction as the central axis is balanced by the pressure reducing valve with the force in this direction, so the balance is temporarily lost, but it recovers quickly. Even in the case of an impact in the axial direction, a component force in the lateral direction is generated due to a displacement of some force, but the displacement caused by the displacement is also within the above range. In response to this impact, in the experiment under the above operating conditions, the deviation of the set secondary pressure was within 20 ± 0.4 kPa. However, when an impact is applied during operation, the recovery is quicker if the primary pressure is temporarily set to 0, that is, the operation is stopped, and then the operation is restarted.

FIG. 3 is a longitudinal sectional view showing the structure of another embodiment of the pressure reducing valve according to the present invention. Here, a corrugated metal diaphragm 50 'is used as a detection element. At this time, the spring seat 55
Between the center of the diaphragm 50 'and the center of the diaphragm 50'
Fix with m. The valve 40 'is frusto-conical and has a transmission rod 41 at the top and a valve rod 42 at the bottom. The valve stem 42 has a guide 46 fitted into the hole 14 dug in the valve body 10 with a gap of about 5 μm.
Slide in the center hole of. The gap between the hole of the valve stem 42 and the hole of the guide 46 is about 10 μm. On the other hand, the guide is not provided on the valve seat plate 30 '. In this embodiment, the transmission rod 41 and the valve rod 42 prevent the first and second dance phenomena.

FIG. 4 is a longitudinal sectional view showing a modification of the embodiment of FIG. Instead of the guide 34 provided on the valve seat plate 30 of the embodiment shown in FIG.
The flange of the bellows 50 where the 70 is placed
It is fitted into the counterbore 68 which is counterbore on the flange of 60,
It is fixed to the valve body 10 with its central axis aligned. The outer diameter of the collar 70 is 100-500 more than the inner diameter of the bellows 50 when compressed.
The length of the collar 70 is about 2 μm, and the length of the collar 70 is about two valleys of the bellows 50 when extended. The collar 70 has an intake hole 69
Is empty. The material is low density and bellows
A slippery one for 50 is used.

FIG. 5 is a longitudinal sectional view showing another modification of the embodiment of FIG. Disconnect the spherical valve 40 and the transmission rod 41, and
Was fixed on the central axis of the lower bottom 52 of the spring seat 55. At this time, a straight through hole 31 opened on the central axis of the valve seat plate 30
The gap between the transmission rod 41 is about 5 to 100 μm. The gap between the protrusion 51 and the guide 34 is about 10 to 100 μm. The gap between the hole 14 and the spherical valve 40 is 5 to 10 μm.
m.

FIG. 6 is a sectional view showing a further modified example of the modified example of FIG. A spring seat 47 is provided between the spherical valve 40 and the valve spring 45. The upper surface of the spring seat 47 is flat, where it contacts the spherical valve 40. Further, the valve seat plate 30 'has no guide of the bellows convex portion 51. Instead, the counterbore 33 is made as shallow as possible to
A counterbore 39 is separately provided on the lower bottom 52 side of 55. At this time,
The gap between the transmission rod 41 and the straight through hole 31 on the central axis of the valve seat plate 30 'is about 5 μm. FIG. 7 shows, in particular,
FIG. 9 is a longitudinal sectional view showing another embodiment of the pressure reducing valve according to the present invention, which is suitable for a case where the flow rate is minute at a minute set secondary pressure. A lower limit stopper 71 is provided at the center of the valve seat plate 30, and an upper limit stopper 72 is provided at the spring seat 56. Spring seat 55 on lower limit stopper 71
When the lower bottom 52 hits, the maximum flow rate flows and the inertia of the impact prevents the bellows 50 from being excessively compressed. The upper limit stopper 72 prevents the upper bottom of the bellows 50 from being abnormally elongated due to excessive secondary pressure or impact inertia. The more the movable range of the bellows 50 is limited by the upper and lower stoppers, the smaller the change in the set secondary pressure with respect to an impact or a restart. In addition, the filter made of sintered metal
97 prevents foreign matter from entering from the primary pressure side, and prevents foreign matter from flowing backward from the secondary pressure side. O-ring 98
Seals the filter 97 to prevent falling off.

FIG. 8 is a longitudinal sectional view of another embodiment of the present invention which is particularly suitable for a case where the flow rate is minute at a small set secondary pressure and which can be used even when the flow rate is large by removing parts; FIG. 9 is a longitudinal sectional view of a modification of the component shown in FIG. The valve seat fitting 77 has a gap of about 10 μm on the counterbore surface 16 of the valve body 10.
Fitted below. A hole 32 is formed in the center axis of the valve seat fitting 77, and the lower surface is formed in two steps, and the valve seat is an O-ring.
36 is arranged on the back facing surface, and the washer-shaped bracket 75 is
The valve seat 36 is pressed down from below. The inner diameter of the metal fitting 75 is slightly smaller than the center of the line of the valve seat 36 which is an O-ring, and the thickness thereof is such that when the spherical valve 40 is in close contact with the valve seat 36 at the time of sealing, the spherical valve is closed.
Do not touch 40. The role of the fitting 75 is to prevent abnormal deformation to the spherical valve 40 side when the valve seat 36 is correctly mounted. A straight through-hole 31 is provided concentrically and vertically in the center axis of the resistance plate 78. At the lower bottom of the resistance plate 78, there is a counterbore 82, and a bypass 79 penetrates vertically. The bypass 79 can be hermetically sealed by an O-ring 81 and a screw 80. The valve seat fitting 77 and the valve body 10 are
The valve 37, the resistance plate 78, and the valve element 10 are hermetically sealed together by an O-ring 83 with screws 38 by a ring 37. The valve seat 47 'includes a spherical counterbore 73 having a radius larger than the radius of the ball of the valve 40, and a stopper 74 so that the spring 45 does not receive an excessive compressive force due to an impact during transportation or the like.

The gap formed by the outer diameter of the transmission rod 41 and the inner diameter of the linear through hole 31 of the resistance plate 78 is sufficiently sandwiched between the transmission rod 41 and the resistance corresponding to the desired degree of pressure reduction and the flow rate. In this way, a very stable set secondary pressure can be obtained. To obtain a large flow rate, remove the screw 80. To obtain an intermediate flow rate, a hole 85 corresponding to the intermediate flow rate may be provided in the center of the screw 80 as shown in FIG. The gas flowing through the gap formed by the transmission rod 41 and the linear through-hole 31 increases in viscosity as the temperature rises, and the flow rate decreases. Therefore, the member of the resistance plate 78 in which the linear through hole 31 is formed has a larger coefficient of thermal expansion than the member of the transmission rod 41. In this way, the design can be made so as not to decrease the flow rate.

10 and 11 are partial sectional views showing an embodiment in which the gap between the hole and the transmission rod in the embodiment of FIG. 8 is not constant at the center axis. In FIG. 10, the straight through hole 31 is cylindrical and has the same diameter over the length of the central axis, whereas the transmission rod 41 is conical and has a large diameter on the spherical valve side. In FIG. 11, the straight through-hole 31 is the same as that described above, and the transmission rod 41 is a cylinder, but one side thereof is cut off on a surface inclined with respect to the central axis, and the cut-off side of the spherical valve is cut off. Is smaller. As described above, the gap formed between the linear through-hole 31 and the transmission rod 41 and forming the flow path resistance is not constant on the center axis of the linear through-hole 31 and is transmitted due to a decrease in the secondary pressure. When the rod 41 moves to the right side in the figure, the gap increases smoothly, and the flow path resistance decreases. That is, the change in the secondary pressure is constant in the case of FIG. 8, but changes in the present embodiment.

FIG. 12 is a partial cross-sectional view showing an embodiment in which the end face of the compensation spring is engaged so as not to be separated from other components. Compensation spring 58
Are provided with two or more tightly wound spring seats 91 at both ends. The bellows 50 is provided with a protrusion, and has an external thread 92 formed so as to be screwed into a spring seat 91. Spring seat
55 is provided with a female screw 93 so that a spring seat 91 at the other end of the compensation spring 58 can be screwed therein. A shoulder 95 of a hole formed in the center of the spring seat 55 is chamfered to have a slope of about 1 mm, and the slope is finished to have a roughness of about 1 μm. The end of the adjusting screw 65 penetrates loosely into the hole of the spring seat 55, and the spherically finished shoulder 94 is adapted to abut the shoulder 95 of the spring seat 55 so as not to separate from the spring seat 55. Stopped by a retaining ring 96. Lubricant is applied to the contact surfaces of the shoulders 54 and 55 so that the spring seat 55 does not rotate due to the rotational force of the adjusting screw 65,
If necessary, the seat 91 and the female screw 93 and the male screw 93 and the male screw are coated with anti-loosening paint. Although not shown, in a similar manner, the valve spring 45
To stop the spring seat 47 (or 47 ').

According to the embodiment of the present invention described above, a pressure reducing valve that stably maintains the secondary pressure once set can be obtained with a simple configuration in which only a small number of parts are added and the shape of the parts is changed. According to experiments, for example, primary pressure 50 ± 10 kPa, secondary pressure
When the flow rate was set to 20 kPa and the flow rate was set to 33 ml / min, it was confirmed that the deviation of the set secondary pressure was within about 0.2 kPa.

〔The invention's effect〕

According to the present invention, there is provided means for restricting the movement of the movable valve so that the sealing circle of the movable valve always keeps the same coaxial gap with the sealing circle of the valve seat over the movable range of the movable valve. With the provision, the displacement of the movable valve can be eliminated, and the fluctuation of the set secondary pressure can be suppressed.

In addition, by restricting the movement of the central axis of the pressure detecting element and the central axis of the secondary pressure adjusting compensation spring so as to move only on the same trajectory as the restricted movement of the movable valve, the displacement of the movable valve is suppressed. However, fluctuations in the set secondary pressure can be eliminated.

Further, means for preventing the pressure detecting element and its compensating spring, and the connecting portion of the compensating spring and the secondary pressure setting spring from being separated in the direction of the central axis, are provided. Providing a means for preventing the connecting portion from separating in the direction of the central axis eliminates resonance of the compensation spring or the secondary pressure setting spring, thereby suppressing valve vibration and eliminating fluctuations in the set secondary pressure. Can be.

Therefore, a pressure reducing valve having a mechanism capable of stably maintaining the secondary pressure once set is obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing the structure of one embodiment of a pressure reducing valve according to the present invention, FIG. 2 is a transverse sectional view showing the periphery of a hole in the embodiment of FIG. 1, and FIG. FIG. 4 is a longitudinal sectional view showing a modified example of the embodiment of FIG. 1, and FIG. 5 is a longitudinal sectional view showing another modified example of the embodiment of FIG. 6, FIG. 6 is a longitudinal sectional view showing a further modified example of the modified example of FIG. 5, FIG. 7 is a longitudinal sectional view showing another embodiment of the pressure reducing valve according to the present invention, and FIG. FIG. 9 is a longitudinal sectional view showing another embodiment, FIG. 9 is a longitudinal sectional view of a modification of the part shown in FIG. 8, and FIGS. 10 and 11 show the embodiment shown in FIG. FIG. 12 is a partial cross-sectional view showing an embodiment in which the end surface of the compensation spring is not fixed to the center axis, and FIG.
The figure is an end view of the helical spring shown in JIS. 10… Valve, 11… Primary port, 12… Secondary port, 14…
Hole, 30, 30 '... valve seat plate, 31 ... linear through hole, 34 ... guide, 36 ... valve seat, 40 ... spherical valve, 40' ... valve, 41 ... transmission rod, 42… Valve stem, 47… Spring seat, 50… Bellows, 50 ′… Diaphragm, 51… Protrusion, 70… Collar, 71… Lower limit stopper, 72… Upper limit stopper, 79… Bypass .

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G05D 16/06

Claims (1)

(57) [Claims] 1. A valve seat member having a straight through hole and disposed between a primary pressure side and a secondary pressure side, a movable valve disposed on a primary side with respect to the valve seat member, and the valve A pressure reducing valve comprising: a bellows disposed on the secondary side with respect to the seat member and having a convex portion; and a transmission rod fixed to a bottom portion of the convex portion and transmitting the movement of the convex portion to the movable valve. A guide portion extending in a direction parallel to the through hole and linearly moving the convex portion only in the parallel direction is formed on the bellows side of the valve seat member; and the transmission rod is formed in the linear through hole. A pressure-reducing valve, wherein the movable valve is moved while keeping coaxial with the valve seat member in accordance with the linear movement of the projection.