JPS61109978A - Positive and negative pressure relief valve having pilot valve - Google Patents

Abstract

PURPOSE:To provide a compact and light weight device that allows an accurate setting of the relief pressure by controlling the opening and closing of a pressure pilot valve and a vacuum pilot valve by multiple airtight extendable members that are operated in response to a pressure change of pressure fluid in the container. CONSTITUTION:Pilot valve chambers 47, 48 are respectively provided in cases 38, 39, and valve seats 49, 50 are fixedly attached to said valve chambers. For opening and closing said valve seats, a pressure and a vacuum pilot valves 51, 52 are provided. Valve stems 57, 58 connected to the respective valves 51, 52 are inserted into tubular adjusting screws 60, 61. A connecting rod 68 penetrates the center of diaphragms 41, 42, 43 in an airtight manner. The ends of the connecting rod 68 oppose the inner surface of the valves 51, 52 in a closed position with a slight gap in between.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention is applicable to positive pressure and negative pressure used in pressure vessels that receive positive pressure and negative pressure, such as gas tanks for city gas, liquefied natural gas, etc., or oil tanks. Concerning a safety valve with a dual-purpose pilot valve. It is something.

[Conventional technology]

The illustrated figure shows a conventional safety valve with a pilot valve. In this figure, 1 is a pressure vessel, and 2 is a mounting nozzle mounted on the top of the pressure vessel. A hollow main body 3 is fixed to this nozzle holder 2, and a pressure pilot valve 7 and a vacuum pilot valve 8 are mounted on this main body 3 by means of a 7-shaped connecting pipe.

An air outlet 5 is provided on one side of the main body 3, and a dome 6 is provided on the top.
and a main diaphragm 1 as an example of an airtight telescopic part set.
0 is fixed, and the main valve body 11 for opening and closing the valve seats 9 of the three gates of the main body is fixed at the center thereof.

When the pressure inside the container 1 is positive and has not reached a predetermined blowout pressure number, the fluid pressure inside the container 1 is applied to the lower surface of the main valve body 11 and is also applied to the lower surface of the main valve body 11 through the vibrator 12 and the check valve 14. , are applied above and below the upper diaphragm 15 and the lower diaphragm 16 of the pressure pilot valve 7, but the valve body 18 of the pilot valve 7 closes the valve seat 20 leading to the connecting pipe due to the load of the spring 19. .

However, since the inside of the valve seat 20 communicates with the vibrator 12 and the connecting pipe →, the fluid pressure inside the container 1 is applied to the dome 6.

In addition, the lower and upper parts of the diaphragm 22 at the lower part of the vacuum pilot valve 8 are applied via the vibrator 12-1 t+ -20-4 (the pressure inside the container 1 is also applied to the lower part of the diaphragm 21, but Since the pressure from the vibrator 23 advancing into the container 1 is applied to the upper part of the diaphragm 21 at the upper part of the pilot valve 8, and the load of the spring 24 is also applied, the valve body 25 presses the valve seat 26 communicating with the connecting pipe 4. Closed.

Therefore, the force of the pressure fluid applied to the upper part of the main diaphragm 10 is greater than the force of the pressure fluid applied to the lower part of the main valve element 11, so the main valve element 11 closes the valve seat 9.

Now, when the pressure of the fluid in the container 1 approaches the blowing pressure,
The force pushing up the upper diaphragm 15 of the pressure pilot valve 7 and the load of the spring 19 are balanced, and the valve body 1B opens slightly.

Therefore, the pressure fluid in the dome 6 and the pilot valve 7 is slightly discharged through the pilot discharge pipe 28.

In this way, as the pressure inside the container 1 increases, the diaphragms 15 and 16 of the pilot valve 7 are pushed up, and the valve seat 2
As the opening of 0 increases, the pressure inside the dome 6 decreases, and finally the pilot valve 7 fully opens.
The pressure fluid in the container 1 is discharged from the discharge pipe 28, the main valve body 11 is also fully opened, and the pressure fluid in the container 1 is blown out from the outlet 5.

When the daily fluid pressure in the container decreases due to the pressure fluid being blown out from the outlet 5, the amount of discharge from the pilot valve 7 decreases, and as a result, the pressure fluid entering the dome 6 is accumulated. The pressure increases by L, and the main valve body 11 closes the valve seat 9.

Further, when the pressure inside the container 1 decreases, the valve body 25 of the vacuum pilot valve 8 closes the valve seat 26 due to the load of the spring 24 until the pressure reaches a predetermined suction pressure.

At this time, the atmosphere suction vibe 29 of the vacuum pilot valve 8
from the check valve 30 and passes through the connecting pipe 4 to the dome 6.
The main valve element 11 closes the valve seat 9 because the force due to the atmospheric pressure applied during the day is greater than the force of the valve seat 9 which tries to push up the main valve element 11.

As the pressure inside the container decreases further and approaches the suction pressure,
Pushing the diaphragm 21° 22 of the vacuum pilot valve 8, the force to raise it and the load of the spring 24 are balanced, and the valve body 25 slowly separates from the valve seat 26, and the fluid inside the dome 6 and the pilot valve 8 is released. is slightly discharged into the container 1 via the vibrator 13.12.

As a result, the pressure inside the dome 6 and the pilot valve 8 yen further decreases, the valve body 25 is fully opened, and when the fluid inside the dome 6 is further discharged into the container 1, it acts on the top and bottom of the diaphragm 10. The balance between the forces is broken and the main valve body 11 is fully opened, allowing air to flow into the container.

The main valve body 11 is open while the pressure in one container is lower than the suction pressure, and when the pressure in one container increases and the vacuum pilot valve 8 begins to close, the amount of discharge from this valve 8 increases. The fluid flowing into the dome 6 is accumulated and the pressure inside the dome 6 increases, causing the main valve body 11 to close the valve seat.

[Problem that the invention seeks to solve]

The above-mentioned pilot valve side safety valve is excellent in that one safety valve doubles as a pressure safety valve and a vacuum safety valve.
Since two pilot valves, a pressure pilot valve and a vacuum pilot valve, are required on the main body, there are problems such as large size and heavy debt.

[Means for solving problems]

In order to solve the above problems, the present invention installs three airtight elastic members in the main body of one pilot valve,
Each member has four isolated chambers, and the chambers on both sides of the airtight elastic member in the center communicate with the inside of the container via a check valve and a throttle valve, and one of the chambers on the outside of the airtight elastic member on both sides communicates with the inside of the container through a check valve and a throttle valve. communicates with the pressure vessel, one chamber is provided with a valve seat that communicates with the dome, the other chamber is provided with an outlet that communicates with the atmosphere, and a valve that communicates this chamber with the throttle valve and the dome. A pressure pilot valve element for closing each valve seat from the outside, a vacuum pilot valve element, and an adjustable spring for compressing each pilot valve element against the valve seat are provided, respectively. The airtight telescopic part moves together with the moon to push open each pilot valve element from the valve seat side (an interlocking rod is provided).

[For production]

Since this invention has the above configuration, while the pressure inside the pressure vessel is higher than atmospheric pressure and has not reached the blowing pressure, the airtight elastic member, that is, the diaphragm inside the pilot valve does not work, and the pressure vessel When the pressure reaches the blowout pressure, the diaphragm acts to open the pressure pilot valve element or the valve seat, and this valve seat releases the fluid inside the dome of the safety valve to the atmosphere, causing the main valve element to fully open and reduce the pressure. Pressure fluid within the container is discharged to the atmosphere from the outlet.

In addition, when the pressure inside the pressure vessel decreases to the suction pressure while the main valve body is closing the valve seat, the diaphragm inside the pilot valve operates and the vacuum pilot valve body opens the valve seat. The inside of the dome is communicated with the inside of the container and the main valve body is fully opened.

〔Example〕

1 to 3 show examples of the present invention, and the main body 3 in FIGS. 2 and 3 has the same cylindrical internal structure as the conventional main body 3 shown in FIG. Explanation will be omitted.

35 is the main body of a pilot valve that serves both for pressure and vacuum, and there is an example of an airtight elastic member between the pair of ring-shaped retainers 36 and 37, and between the right case 3B and the left case 39. The diaphragms 41, 42, and 43 are sandwiched between them, respectively, and these are coupled together by means of bolts or the like. Further, spring boxes 45 and 46 are fixed to each case 38 and 39 by means of bolts or the like.

Each case 38, 39 contains a pilot valve chamber 47.
．． 48, a valve seat 49.50 is fixed to each valve chamber, and pilot valve bodies 5L52 for pressure and vacuum are provided to open and close the valve seats 49.50, and each valve body 515
The springs 55 and 56 that apply a spring load to the spring box 45
．． 46.

Reference numerals 57 and 58 indicate valve stems connected to the respective valve bodies 51 and 52, and these valve stems 5 and 58 are loosely fitted into tubular adjusting screws 60 and 61.

This adjustment screw e:io, 61fo each spring box 4! b,
A spring holder 62.63 is attached to the inner end of the spring holder 62, 63, and the spring 55. 56 is interposed. Also, spring receiver 64.6
A diaphragm 66.67 is attached to the portion 5, and its periphery is sandwiched between the spring boxes 4b, 46 and the cases 38, 39, thereby blocking the valve chambers 47, 48 and the spring boxes 45, 46.

An interlocking rod 68 is passed through the center of each diaphragm 41, 42, 43 in an airtight manner, and a moss spacer, diaphragm holding plate, set plate nut, etc. is fixed to the interlocking rod 68, and each diaphragm 41, 42, 43 is connected to the interlocking rod 68. 43 is configured to move forward and backward together with the interlocking rod 68 at a constant interval, and both ends of the interlocking rod 68 are opposed to the inner surfaces of the valve bodies 51 and 52 in the closed position with a very small gap. .

70.71 is a communication passage communicating with each valve chamber 47.48, the outer end of which is closed, and both communication passages 70.71 are connected to the tenor 3.
6.37 and the communication passage 73 passing through the case 38.39
One end of this communication path 73 is closed, a pipe 75 is connected to the bent end, and this vibe 75 is connected to the second tube 1 and the dome 6 as shown in FIG. 3.

Further, another communicating passage 76 leading to the valve chamber 47 is provided, and a communicating passage 78 leading to the chamber 77 on the left side of the diaphragm 43 is provided in the case 39, and the outer ends of each of these communicating passages 76, 78 are closed. , both communication passages 76 and 78 are communicated by a communication passage 79, and a needle valve 80 as an example of a throttle valve is provided in this communication passage 79.Furthermore, from the 7th day onwards, the communication passage opens to the needle valve 80 side, but the A check valve 81 that does not open in the opposite direction is provided. In addition, the communication path 78 is connected to the main body 3 by pipes 82 and 83.
The inside of the valve seat 9 and the inside of the spring box 46 on the left side in FIG.

The communication path 79 connects the diaphragm 41 with the communication path 85.
The needle valve 80 and the check valve 81 are connected to a chamber 86 between the needle valve 80 and the check valve 81. Diaphragm 41,4 by 89
The chamber 91 on the right side of the diaphragm 42
is released to the atmosphere through an outlet 92 provided in the case 38.

First, the operation of the above embodiment will be explained, or the operation inside the main body 3 will be explained based on FIG.

When the pressure inside the container 1 is positive and does not reach the preset blowout pressure, the pressure of the fluid in the container 1 is applied to the lower surface of the main valve body 11, and the pressure of the fluid in the container 1 is applied to the lower surface of the main valve body 11, and the pressure of the fluid in FIG. The pressure fluid enters the chamber 77 through the communication passage 78, opens the check valve 81, and flows into the chamber 90 through the communication passage 89.

Further, the same pressure fluid is supplied from the needle valve 80 to the communication path 85.
．． It also flows into the chamber 86 and the pilot valve chamber 47 . At the same time, pressure fluid also enters the spring box 45 from the pipe 83.

In this state, the fluid pressures on both sides of the central diaphragm 41 are equal, and the fluid pressures on both sides of the diaphragm 43 are also equal.

Also, inside the dome 6 are a pipe 75 and a communication path 70°73.
71 and 76 communicate with the valve chambers 47 and 48 and the communication passage 79, so that the pressure fluid from inside the container 1 reaches them.

In this state, fluid pressure is applied to the right only at the diaphragms 42 and 66, but the valve body 51 is pressed against the valve seat 49 by the cart of the spring 55, and the valve body 52 is also pressed against the valve seat 49 by the spring 55.
The valve seat 50 is pressed against the valve seat 50 by a load of 6.

Therefore, the main valve element 11 is pressed against the valve seat 9 by the fluid pressure applied to the upper part of the diaphragm 10 to which the main valve element 11 is attached.

When the pressure of the fluid in one yen of the container approaches the blowout pressure, the force pushing the right diaphragm 42 to the right increases, and the right end of the interlocking rod 68, which moves together with the diaphragm 42, pushes the valve body 51, but this pushing force increases. The load of the spring 55 is balanced and the valve body 51 opens slightly.

Therefore, the fluid inside the dome 6 is transferred to the pipe 75 and the communication path 70.
, a small amount is discharged into the atmosphere through the valve seat 49, chamber 91, and discharge port 92.

In this way, as the pressure inside the container 1 rises, the opening degree of the valve body 51 increases, and the passage 76-
When the flow l of the pressure fluid flowing from the valve seat 49 to the chamber 91 to the discharge port 92 and being discharged to the atmosphere becomes large, the fluid in the container 1 passes through the pipe 82 because the check valve 81 is open. room 8
6, but since it is restricted by the needle valve 80, a pressure difference occurs between chamber 90 and chamber 86, and a large force flows into chamber 90.
Then, the diaphragm 42 moves further to the right together with the interlocking rod 68, compressing the spring 55 and fully opening the valve body 51.

Therefore, the pressure fluid in the dome 6 and the fluid in the container 1 whose pressure is regulated by the needle valve 80 are discharged from the discharge port 92.

When the pressure fluid in the dome 6 is thus exhausted and a pressure drop occurs in the dome 6, the main valve body 11 opens and the pressure fluid in the container 1 is blown out from the outlet 5 into the atmosphere. The main valve body 11 and the pilot valve body 51 are fully open while the pressure inside the container 1 is higher than the blowing pressure. The amount of pressure fluid discharged from the exhaust port 92 decreases, and the flow rate of the pressure fluid entering the dome 6 through the communication path 70 is accumulated, and the pressure inside the dome 6 increases.
The main valve body 11 is fully closed by overcoming the downward pressure of the pressure fluid pushing the main valve body 1 and the diaphragm 10 or the upward pressure from the container 1 side pushing the main valve body 11 from the inside.

Next, the suction action when the inside of the container 1 reaches negative pressure fj will be explained.

The pilot valve body 52 is closed by the load of the spring 56 until the pressure inside the container 1 reaches a preset suction pressure.

The 6 gates of the dome are the pipe 75, the communication path 70° in Figure 1, and the valve chamber 4.
7, communication passages 76, 79, 85, chamber 86, atmosphere suction pipe 88 shown in FIGS. 2 and 3, and check valve 87 to communicate with the atmosphere. Therefore, when the pressure inside the container 1 is negative, the check valve 87 opens and the atmospheric pressure sucking the atmosphere into the dome 6 is higher than the pressure inside the container 1 that tries to push up the main valve element 11. Valve body 11 is closed. now,
When the pressure in the container 1 yen further decreases and approaches the preset suction pressure, the pressure in the chamber γ7 shown in FIG.
The force pushing the left end of the valve 8 or the pilot valve body 52 and the load of the spring 56 are balanced, and the valve body 52 opens slightly.

Therefore, the air inside the dome 6 is transferred from the pie differential 5 to the communication path 73.
→ A1 → Valve chamber 48 - Inside of valve seat 50 - Chamber 77 → Communication passage 78 →
It flows with the vibe 82 and is slightly discharged into one container.

As a result, the pressure in the chambers 90°86 on both sides of the diaphragm 41 decreases, or the chamber 86 sucks in atmospheric air through the check valve 8, and since the communication passage 85 is narrowed, the pressure in the chamber 90°86 decreases.
．． A pressure difference occurs at 86.

Also, since the diaphragm 41 has a large area, the chamber 90.
When a pressure difference occurs at 86, a large force is generated, which causes interlocking rod 68 to forcefully push valve body 52 open.

When the pilot valve body 52 is fully opened in this way, the dome 6
Since the air inside is discharged into the container 1 approaching the vibrator 82, a pressure drop occurs in the dome 6, and the balance of the forces acting above and below the main valve body 1 is disrupted, causing the main valve body 1 to fully open fj. A large volume of outside air is sucked directly into the container 1 from the valve seat 9.

While the pressure inside the container 1 is lower than the suction pressure, the main valve body 11
is kept fully open, and when the pressure inside the container 1 increases and the pilot valve body 52 attempts to close, the amount of air flowing into the container 1 through the valve seat 50 decreases, and the amount of air entering the dome 6 decreases. The pressure inside the dome 6 increases and the diaphragm 1
0, the main valve body 11 fully closes the valve seat 9.

In the embodiment, a diaphragm is used as the airtight elastic member, but if there are problems with corrosion resistance, low temperature resistance, high temperature resistance, etc., a bellows or the like is used.

Further, the main body 35 of the pilot valve may be installed horizontally on the dome of the safety valve as shown in FIG. 2, or vertically as shown in FIG.

〔effect〕

This invention (as mentioned above, in a safety valve with a pilot valve, the main body of the pilot valve is one, which is attached to a dome on a hollow body attached to a pressure vessel, and the pressure of the pressurized fluid in the vessel is inside the main body of this pilot valve. A plurality of airtight elastic members such as diaphragms that move with the change are provided to move the interlocking rod, and this movement opens and closes the pressure pilot valve body and the vacuum pilot valve body, causing pressure fluid to flow into the dome. The valve seat is opened and closed by the main valve element fixed to the airtight elastic member such as a diaphragm inside the dome, which is operated by letting external air flow in and out, and the valve seat is opened and closed using the main valve body fixed to this. Compared to a safety valve that has pilot valves for air and vacuum, it is smaller and lighter.

In addition, each pilot valve for pressure and vacuum can be adjusted independently by pressing the pilot valve against the valve seat and adjusting the spring that applies the load, so the operating pressure for pressure and vacuum can be adjusted independently. You can set it accurately. Other benefits include accurate adjustment using a throttle valve such as an on-needle valve.

[Brief explanation of drawings]

Figure 1 is an enlarged longitudinal sectional view [1] of the main part of this invention, Figure 2
Fig. 3 (; Front view showing each couple of this invention, Fig. 4 (
FIG. 2 is a longitudinal sectional front view of a conventional safety valve. 1... Pressure vessel, 3... Main body, 6... Dome, 9
... Valve seat, 10... Main diaphragm, 11... Main valve body, 35... Main body of pilot valve, 41.42.4
3...diaplum, 49.50...valve seat, 51...
・Pilot valve body for pressure, 52... Pilot valve body for vacuum, 55, 56... Spring, 68... Interlocking rod, 7
7.90, 86.91... Chamber, 80... Needle valve, 92... Outlet. Patent applicant Fukui Seisakusho Co., Ltd. Agent
Sickle 1) Bunji Figure 3 Figure 4 Procedural Amendment (Toge) January 25, 1985, 1985, 59th year of the Appearance Certification θf, 1 No. 233999 2゜ Name of Jingmei Positive pressure/negative with pilot valve Relationship between pressure-actuated safety valve 3 and the person making the amendment 1'F Patent applicant f, 1g l (r 1-6 Shodaita-chika, Hirakata-shi, Osaka Prefecture, name changed) Fukui Seisakusho Showa Co., Ltd. Month Day (Shipping date) ) Correction details 1. "Flow rate of pressure fluid" at the end of page 14 of the specification will be corrected to "pressure fluid". 2. On page 16, line 19 and from line 19 to line 20, the words "main valve element 1" will be corrected to "main valve element 11."

Claims (1)

[Claims] A valve seat communicating with the pressure vessel is provided in a hollow body mounted on the pressure vessel, and a main valve body for opening and closing the valve seat is provided in an airtight elastic member sandwiched between the body and the dome at the top of the body. It is actuated by the pressure change of the pressure fluid inside the dome to control the flow of fluid into and out of the dome, and fully opens the main valve body when the fluid pressure inside the container reaches a preset blowout pressure or suction pressure. In a safety valve equipped with a pilot valve, three airtight elastic members are attached to the main body of one pilot valve, and four chambers isolated by these members are provided, and a central airtight elastic member is installed. The chambers on both sides of the dome communicate with the inside of the container via a check valve and a throttle valve, and one of the chambers outside the airtight elastic member on both sides communicates with the pressure vessel, and this one chamber has a valve that communicates with the dome. The other chamber is provided with a discharge port that communicates with the atmosphere, and a valve seat that communicates this chamber with the throttle valve and the dome, and a pressure pilot valve element that closes these valve seats from the outside. , a vacuum pilot valve body, and an adjustable spring that presses each pilot valve body against the valve seat, and an interlocking rod that moves together with each airtight elastic member to push open each pilot valve body from the valve seat side. A positive and negative pressure operated safety valve with a pilot valve.