JPS5829865B2 - Bourdon tube pressure gauge safety device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a technique for improving safety in, for example, a primary side pressure gauge of a pressure regulator or a Bourdon tube pressure gauge used for measuring fluid pressure in various fluid pipelines.

For example, when extracting oxygen from a high-pressure cylinder by lowering it to the desired pressure, the container valve must be opened gradually in accordance with the regulations, but even so, the high-pressure fluid flows out suddenly due to the large diameter of the valve. However, when the valve is opened, a large pressure is momentarily applied to the high-pressure side pressure gauge of the pressure regulator, and the Bourdon tube inside the pressure gauge may be damaged.

Moreover, since the opening operation of such container valves tends to be quick, the actual risk is even higher, and if the valve is opened rapidly due to such use, it will directly lead to an accident that breaks the Bourdon tube. Easy and extremely dangerous.

Also, for example, backfire may occur during welding work and abnormal pressure is applied to the oxygen or acetylene pipeline, or the downstream pipeline may be blocked due to the pipeline being bent or being trampled by a heavy object. If the fluid pressure in the pipeline rises abnormally, such as in the event of an accident, there is a risk that a similar Bourdon tube breakage accident will occur in the pressure gauge attached to the pipeline.

For this reason, as illustrated in FIG. 3, consideration was given to buffering the introduction pressure when the container valve is opened by constricting it at the starting end of the pressure fluid introduction path 06 of the Bourdon tube pressure gauge 05A and screwing a so-called insect 07. However, there is a limit to the size of the cross-sectional area of the constricted part formed in the insect 07 due to the manufacturing process, and in practice, the limit is to provide a through hole with a diameter of 0.1 mm. Therefore, as described later, the pressure buffering effect is
This is insignificant compared to the case where 7 is not included, and it is not only insufficient as a measure to prevent damage to the Bourdon tube, but also
Even if such measures are taken, in the unlikely event that the cylinder falls over or collides with another object and the Bourdon tube is destroyed, a large amount of gas will inevitably be ejected from the damaged point. However, safety was not sufficiently ensured in this respect.

The safety device for the Bourdon tube pressure gauge according to the present invention was developed in view of the current situation, and the Bourdon tube pressure gauge is installed by forming a fine passage inside the branch pipe to allow the passage of a small amount of fluid. A valve body is inserted, and the valve body is brought into close contact with the end face of the pressure fluid introduction path to the Bourdon tube due to the generation of a pressure difference between the primary side and the secondary first law as the pressure of the downstream fluid increases. By blocking the introduction path and eliminating the differential pressure caused by the pressure fluid flowing into the secondary side through the fine passage in the valve body in this closed state, the valve body is moved away from the end face of the pressure fluid introduction path. The structure is configured such that the close contact is released and the blockage of the introduction passage is released, and further, the mounting is arranged such that the valve body is mounted in a position on the upper side of the primary fluid passage than the valve body in the branch pipe from the end face of the pressure fluid introduction passage. The present invention is characterized in that a regulating portion is provided to prevent the primary fluid passage from being blocked by a separate valve body.

Therefore, there is no need to make or process the pressure fluid introduction path extremely narrow to open the valve or during pressure measurement.
When abnormal high-pressure fluid flows into the pipeline for some reason, the differential pressure generated between the primary and secondary sides in front of the valve body causes the valve body to come into close contact with the end face of the pressure fluid introduction path, blocking the introduction path. In this state, the pressure fluid gradually flows into the Bourdon tube through the fine passage of the valve body, exerting a remarkable pressure buffering effect, and preventing the Bourdon tube from being damaged due to an instantaneous pressure increase. Even if the Bourdon tube is destroyed due to an external cause such as contact with an object, the valve body will be closed due to the pressure difference, functioning as a safety valve that suppresses fluid ejection from the broken point, ensuring safety. It is.

In addition, in a state where the pressure in front and behind the valve body is equalized due to fluid inflow through the fine passage of the valve body in the closed state, the closed state due to the differential pressure is released and the valve body returns to the open position, or At least, the urging force that maintains the valve in the closed position is released, so that the pressure fluid inside the Bourdon tube can be quickly released when the valve is closed or when the cause of abnormal pressure rise is removed.

In particular, in the present invention, when the valve body is separated from the end face of the pressure fluid introduction path, that is, when the differential pressure disappears in the fluid passage on the downstream side and the secondary side, or when the downstream side pressure is If the pressure becomes lower than , the pressure fluid in the Bourdon tube can be quickly discharged to quickly prepare for the next pressure detection.

Furthermore, since the valve body has a fine passage formed therein to allow the passage of a small amount of fluid, the surface of the valve body that frequently comes into contact with the end face of the pressure fluid introduction path is not worn out. However, it has almost no effect on the area of the micro passage, and is therefore advantageous in that the degree of passage of micro fluid can be maintained at a substantially constant value over a long period of time, allowing stable pressure detection. It is.

Hereinafter, an embodiment in which the present invention is applied to a high-pressure side pressure gauge of a pressure regulator for a high-pressure gas container will be described based on the drawings.

FIG. 1 shows an example of a pressure regulator, in which 1 is a handle for attaching the oxygen cylinder to the pressure vessel, 2 is a pressure adjustment handle, 3 is a container valve (not shown, a force opening/closing operation handle,
4 is a pressure fluid outlet, 5A is a Bourdon tube pressure gauge communicating with the high pressure side of the pressure regulator, and 5B is a Bourdon tube pressure gauge communicating with the low pressure side.

In this embodiment, the pressure gauge 5A is installed by interposing a valve body 7 having a fine passageway that allows passage of a small amount of fluid, as described later, in the branch flow path of the pressure regulator main body, which is an example of the branch pipe 9. Therefore, due to the generation of a pressure difference between the primary side and the secondary side due to the rise in the pressure of the downstream side fluid, the valve body 7 is brought into close contact with the end surface 6a of the pressure fluid introduction path 6 to the Bourdon tube, and its introduction Road 6
The pressure difference is eliminated by once blocking the valve body 7 and allowing a small amount of fluid to flow from the introduction path 6 into the Bourdon tube through the fine passage of the valve body 7 in this closed state, thereby causing the valve body 7 to be closed to the point where pressure fluid is introduced. The structure is such that the introduction channel 6 is automatically unblocked by releasing the close contact from the end surface of the channel 6.

Reference numeral 8 denotes a filter which is an example of a regulating portion, and when the valve body 7 is separated from the end face of the pressure fluid introduction path, the valve body 7 closes the primary fluid passage due to its own weight or the pressure of the secondary fluid. This is to prevent this from happening.

According to the above embodiment, when the pressure regulator is installed with the pointer of the pressure gauge 5A facing upward, opening the container valve allows the pressure regulator to be installed as shown in FIG. 2A.

As shown in the figure, the valve body 7 is pushed up and comes into close contact with the periphery of the starting end of the pressure fluid introduction path 6, and the pressure fluid introduction path 6 is closed, so that the pressure fluid is prevented from flowing into the Bourdon tube side.

However, since the valve body 7 is made of a porous material with minute open cells, such as a metal filter, and has fine passages that allow the passage of a small amount of fluid, the pressure fluid can flow through the valve body 7. When the pressure is equalized inside and outside the valve body 7 and the pointer of the pressure gauge 5A remains stationary at a predetermined value, the close contact is released and the pointer of the pressure gauge 5A is slowly raised. As shown in c, it falls due to its own weight.

When the work is finished and the container valve is closed, if the pressure gauge has the insect 07 inserted as shown in Figure 3, the flow path is constricted, which prevents the release of the pressure fluid inside the pressure gauge. However, in the case of this embodiment, since the valve body 7 has fallen due to its own weight, when the container valve is closed, the return of the pressure gauge pointer to the zero point is delayed. , pressure gauge 5A
The pressure fluid inside is quickly discharged to the outside through the filter 8, and the pointer of the pressure gauge 5A instantly returns to the zero point.

Even if the pointer is installed with the pointer facing downward, when the pressure inside and outside of the valve body 7 is equalized, the valve body 7 is pressed against the starting end surface of the pressure fluid introduction path 6 by the pressure fluid. Since the pressure gauge 5A is in a free state and the container valve is closed, the pointer of the pressure gauge 5A instantly returns to zero.

FIG. 4 shows valve bodies 7 of various shapes, materials, and structures, which are selected and used as appropriate depending on the properties of the fluid, operating pressure, etc. The joint valve body will be explained below.

As mentioned above, what is shown in FIG. good.

In the case of such a porous single body, the fluid passing through it is
Since the cylinder 11 flows in and out not only in the axial direction but also from the side surfaces, and the end surface area is relatively large, the amount of fluid passing through it is difficult to be extremely small.

Furthermore, when the valve body 7 is brought into close contact with the end face of the pressure fluid introduction path 6 due to the differential pressure, there is a risk that the porous body may be damaged due to the impactful contact. It is preferable to cover the outer peripheral surface with metal, plastic, etc., leaving minute fluid passages on the surface.

Figures 4-2 are examples of such a device.

In the case shown in FIG. 4, the outer peripheral surface of the cylinder 11 shown in FIG. It reaches the cylinder 11 made of porous material.

The one shown in FIG. 4C is almost the same as the mouth, but is molded so as to leave a small hole 13, which is a microfluid passage, when it is covered with a plastic member 12.

In the case shown in FIG. 4, small protrusions 14 are formed by cutting out the center of both end faces of a cylinder 11 made of a porous material, and the tip portions of these small protrusions 14 are left to be covered with a plastic member 12. It has a structure.

If the valve body 7 having the structure shown in Figure 4-2 is used, the pressure fluid can flow through the small holes 13 or the cylinder 1 made of porous material.
1 and then gradually flows into the Bourdon tube from the pressure fluid introduction path 6 through the small hole 13 or the small protrusion 14, so that the pointer of the pressure gauge 5A slowly rises.

In these embodiments, for example, a plurality of small holes or slits may be provided on the side surface of the valve body so as to allow a small amount of fluid to pass from the lower end surface to the upper end surface.

The materials shown in FIG.
The one shown in Figure E is one in which the outer peripheral surface of a cylinder 11 made of a porous material is covered with a cylindrical member 12 made of metal or plastic. A small hole 13 is formed protrudingly in the center of the end surface, and a mesh 2 is inserted into this.
This is a box-shaped hollow member made of plastic, as shown in FIG. Small holes 13 are drilled in the upper and lower end surfaces of the cylinder 12, and an open-cell porous foaming agent is injected and foamed to form the cylinder 11.

The above seven types of valve bodies use porous materials or their substitutes to form fine passages that allow the passage of minute amounts of fluid, and allow fluid to pass through the fine gaps. Other materials and structures can also be used to provide microchannels for the passage of microfluids.

Examples of these are shown in Figure 4.

The one shown in FIG. 4H is one in which a small through hole 16 is bored in the axial center of a cylinder 15 made of metal or plastic, and the cross-sectional area of the small hole is narrowed by applying pressure from the side. A through hole with a micro cross-sectional area below the above limit can be obtained.

In the fourth diagram, a small hole 18 is provided in the center of the bottom of a hollow cylinder 17 with a bottom, another cylinder 19 is screwed into this hollow part, and the conical tip 20 is inserted into the small hole 18 of the hollow cylinder 17. I'm going to face it.

The pressure fluid once enters the hollow portion 21 through the gap between the two screwed parts, and then flows into the small hole 18 through the gap between the tip 20 of the cylinder 19 and the lower end of the small hole 18, and then enters the pressure fluid introduction path 6.
It gradually flows to.

At this time, the tip 20 of the cylinder 19 plays the role of a needle of a needle valve, and the inflow of fluid into the small hole 20 can be adjusted by adjusting the degree of screwing in the cylinder 19.

Alternatively, a sealant may be used to prevent fluid from flowing in from the threaded portion, and a small through hole 22 may be separately provided in the cylinder 19.

The one shown in Figure 4 is a structure similar to the above,
A flanged cylinder 24 having a small through hole 25 in the shaft portion is fitted into the hollow part of the bottomed hollow cylinder 23.

It is preferable that the tip of the flanged cylinder 24 has a truncated hemispherical shape or a truncated conical shape.

The pressure fluid enters the small hole 25 of the flanged cylinder 24 through the gap between the cylinders 23 and 24, and gradually flows into the Bourdon tube via the pressure fluid introduction channel 6.

At this time, the bottomed hollow cylinder 23 is strongly pressed against the lower end of the flanged cylinder 24 by the pressure fluid, so the gap between the two in this part is extremely small, and only a small amount of fluid can pass through the valve body as a whole. do not.

In the one shown in FIG. 4, a plurality of hollow chambers 27 are provided inside a cylinder 26, and a small through hole 28 is further bored in the shaft portion.

In this case, in order to narrow the through hole 28, the fourth
It is sufficient to use a pressurizing means as described in the embodiment of FIG.

As described above with respect to several embodiments, in the present invention, the valve body 7 having a fine passage having various shapes, materials, and structures that allows passage of a small amount of fluid is interposed in the mounting branch pipe 9 of the pressure gauge. , - When the pressure of the fluid on the downstream side increases, the pressure difference between the primary side and the secondary side brings the valve body 7 into close contact with the end face of the pressure fluid introduction path 6 to the Bourdon tube, and once the fluid introduction path 6 is closed, While maintaining the closed state, a minute amount of fluid is gradually allowed to flow into the Bourdon tube from the pressure fluid introduction path 6 through the fine passage of the valve body 7, thereby preventing damage to the Bourdon tube due to sudden inflow of pressure fluid. I can do it.

Conversely, even when the pressure on the primary side decreases and the pressure on the secondary side increases, the differential pressure causes the valve body 7 to move away from the pressure fluid introduction path 6, causing the same 6 is opened, the pressure fluid in the Bourdon tube quickly flows out.

In order to see the effects of the present invention, we conducted a case in which the pressure fluid introduction path 6 was not penetrated, a case in which so-called insects of several shapes were inserted, and a case in which the valve body 7 according to the present invention was inserted into the pressure gauge installation branch pipe 9. A pressure gauge was attached to the high-pressure gas container, and the time required from the time when the container valve was opened until the pointer of the pressure gauge 5A indicated the pressure value inside the container was compared.

The results are as follows.

If nothing is inserted 0.29 seconds Figure 5 A is inserted 0.305 seconds Figure 5 mouth
0.347 seconds Figure 5 C
0.29 seconds Figure 5
0.51 seconds When Akira Kinai's Figure 4 mouth is inserted 2.8
5 seconds As is clear from this, according to the present invention, it takes about 10 times longer for the pressure gauge pointer to indicate the pressure than conventional pressure gauges, and the pressure buffering effect is dramatically increased. I understand.

This will be explained based on the diagram of FIG. 6, taking as an example a case where this is used in a pressure regulator for a high-pressure gas container.

The pressure inside the Bourdon tube (secondary pressure) increases from zero to the pressure inside the container (minus side pressure) by opening the container valve.

This required time T is plotted above the vertical axis.

The opening speed of the container valve is plotted on the right side of the horizontal axis.

This is the valve opening degree (cross-sectional area S
), it becomes ds/dt.

If the cross-sectional area of the pressure fluid introduction path to the Bourdon tube is S, then curve (11) with S as a parameter.

(12)... is determined experimentally.

In this case, S is a dog in (11) more than in (12).

On the other hand, if the probability (frequency) of the opening speed (ds/dt) when an operator opens a container valve is plotted below the vertical axis, it can be seen that it becomes a curve O.

Also, if the pressure inside the Bourdon tube increases over time T, and the rate at which the Bourdon tube breaks is plotted on the left side of the horizontal axis, the curve will be (bl) for a new product, and (b2) as the number of times it has been used increases. (b3) and the curve moves to the left.

In this way, for example, if the guarantee condition is a% breakage after 10,000 uses, the breakage rate will be this for a pressure rise time of T=L or less (time for the pointer to reach the primary side pressure value). It turns out that the above is the case.

In actual use of the pressure gauge, there is a time T = U at which it is undesirable if the pressure rise time is longer than this, so the appropriate pressure rise time T is naturally U<T. <Determined by L.

On the other hand, it can also be seen from curve O that a very common valve opening speed is between S and Q.

From the above, the safety condition of obtaining a pressure rise time with almost no damage to the Bourdon tube by a general valve opening operation is that the intersection points A, B, C, D Therefore, it can be seen that the curves (11), (12), etc. must intersect with the line S between A and C, and with the line Q between B and D.

Therefore, by reducing S, the curve (11) is obtained.

The conventional way of thinking is to raise (12) upwards, but as mentioned at the beginning, this is extremely difficult due to processing limitations.

On the other hand, in the device to which the present invention is applied, the shape and size of the valve body 7, the area receiving the pressure of the pressure fluid, and the mounting of the pressure gauge (which affects the gap area between the inner wall of the branch pipe and the outer edge of the valve body) are used as parameters to create a curve. (l,′).

(12')... is determined experimentally.

In other words, if the valve opening speed is constant, the pressure increase speed can be changed arbitrarily by changing the shape and size of the valve body.

That is, as described above, in the device to which the present invention is applied, after the pressure fluid introduction path 6 is once closed by the valve body 7, the pressure fluid is configured to gradually flow in through the fine passage that the valve body 7 itself has. In addition, the gap between the inner wall of the pressure gauge mounting branch pipe 9 and the outer edge of the valve body 7 and the area of the lower surface of the valve body 7 are also related to the closing speed of the valve body 7 and the inflow of pressure fluid until the valve body is closed. It is possible to adjust the pressure rise time depending on the shape and size of 7.

As is clear from the figure, in the device according to the present invention, the curves (11'), (4/)... easily connect the intersection points between the line S and A, C, and the line Q between B and D. .

In other words, common valve opening operations are sufficient to maintain safety;
The pressure rise time can be set to an appropriate time (1 to several seconds).

If a dangerous operation such as suddenly opening the valve is performed, a pressure difference suddenly occurs between the negative side and the secondary side, and the valve body 7 instantly closes the pressure fluid introduction path 6. Since it is occluded, the pressure rise time is very long (l,').

(12') corresponds to the part far above the line U, and functions as a kind of safety shutoff valve.

In such a case, once the valve is closed and then opened at an appropriate opening speed, work can be continued without any problem.

In addition, when abnormal pressure is applied to the pressure gauge of the fluid pipe at a work site, the pressure fluid introduction channel is instantly blocked, preventing damage to the Bourdon pipe, and in the unlikely event that the Bourdon pipe breaks. Of course, even in such cases, the danger of high-pressure fluid continuing to be ejected can be avoided by the safety valve.

In addition, when the valve body 7 is in a state where the pressure fluid introduction path 6 is closed, the valve body 7 and the introduction path 6 are
Since it is necessary to make the valve body 7 almost concentric, it is necessary to provide a guide in the mounting branch pipe 9 or use a spring to bring the valve body 7 close to the end of the introduction path 6 in advance so that the movement stroke of the valve body 7 due to the differential pressure can be adjusted. Countermeasures may be taken, such as making the value smaller.

Furthermore, regardless of the mounting orientation of the pressure gauge (even if the pressure gauge pointer is not necessarily upward), the pressure fluid introduction passage 6 is largely open when no differential pressure is applied to the valve body. For example, if a spring is interposed between the end face of the pressure fluid introduction path 6 and the valve body 7 so that the valve body is always open, and the pressure on the primary side increases and a differential pressure occurs. Only the valve body 7 may close the introduction path 6.

This spring can also play the role of the aforementioned guide.

[Brief explanation of drawings]

The drawings illustrate an embodiment of the safety device for a Bourdon tube pressure gauge according to the present invention, and FIG. 1 is a plan view of a pressure regulator for a container;
2A to 3C are longitudinal sectional views of the main parts, FIG. 3 is a longitudinal sectional view of the main parts showing a conventional example, and FIGS. Figures 5A to 2 are longitudinal sectional views illustrating the shape of an insect, and Figure 6 is a diagram showing the operation of the present invention. 6... Pressure fluid introduction path, 7... Valve body,
9... Installation is a branch pipe.

Claims (1)

[Claims] 1. The Bourdon tube pressure gauge is installed by inserting a valve body 7 in the branch pipe 9, which has a fine passage formed therein to allow the passage of a small amount of fluid, so that the pressure between the primary and secondary sides increases as the pressure of the downstream fluid increases. Due to the generation of a pressure difference with the next side, the valve body 7 is brought into close contact with the end face of the pressure fluid introduction path 6 to the Bourdon tube, thereby blocking the introduction path 6, and in this closed state, the fine passage within the valve body 7 is closed. Due to the elimination of the differential pressure caused by the flow of pressure fluid into the secondary side through the valve body 7, the pressure fluid introduction path 6
The pressure fluid is disposed in a position above the valve body 7 in the mounting branch pipe 9 in the primary fluid passage. A safety device for a Bourdon tube pressure gauge, characterized in that it is provided with a regulating part 8 that prevents the primary side fluid passage from being blocked by a valve body 7 located away from an end face of an introduction path 6.