KR20180002030U - Pressure safety valve - Google Patents

Abstract

The present invention discloses a pressure relief valve. According to an embodiment of the present invention, there is provided a pressure safety valve comprising: a first body and a second body in which a working chamber having an opening is formed; A top cap covering an upper portion of the first body; A first bar provided in the space between the first body and the top cap; A second bar connected to the first bar; An opening / closing unit that opens and closes at a lower end of the second bar in accordance with a pressure inside the container; And a spring coupled to the first and second bars to apply elasticity to the opening and closing portions.

Description

{PRESSURE SAFETY VALVE}

The present invention relates to a pressure relief valve, and more particularly, to a pressure relief valve capable of opening and closing one side at an increased temperature.

With the increasing interest of human beings in recent years, there are fossil fuels such as natural gas as well as byproducts from crude oil and crude oil drilling from the ground. In addition, there is renewable energy such as sunlight and solar heat transmitted to the earth by solar energy, wind and wave generated from the earth by this, and tidal force generated by interplanetary attraction.

Of these, in the case of offshore plants producing crude oil or natural gas that can be obtained from the ocean, pressure vessels contain dangerous oils and hydrocarbons in the fire, which can lead to further expansion accidents when exposed to fire.

For example, explosive phenomena such as Boiling Liquid Expanding Vapor Explosions (BLEVE), which evaporate liquids with rapid increase in volume at the time of fire exposure, may occur.

In order to prevent this, Blow Down Valve (BDV) and Pressure Safety Valve (PSV) are applied.

1 is a schematic partial cross-sectional view of a conventional pressure relief valve.

1, the pressure relief valve 1a is provided with a working chamber 13 having an opening 12 therein and having a predetermined depth from the opening 12 to the inner peripheral surface of the working chamber 13 A male threaded engaging portion 16a formed integrally with a lower end of the cylindrical portion 11 and a cylindrical portion 11 forming a fastening screw portion 14 and forming a discharge port 15a of a screw hole through one side, A valve body 10a constituted by an inclined valve seat 17a formed at the upper center of the engaging portion 16a and a pressure inlet 18 communicating with the valve seat 17a; A valve shaft 34 provided at the center of the valve disc 31a and an inclined valve disc 31a formed in the operating chamber 13 for opening and closing the valve seat 17a; An opening / closing part 30a constituted by a plurality of compression springs 35a and 35b accommodating and accommodating the plurality of compression springs 35a and 35b; A compression screw portion (not shown) for tightening the compression springs 35a and 35b and forming a guide hole 43 having a predetermined depth for guiding the inserted valve shaft 34 up and down, And a fastening space 45 is formed on the inner side of the tool connecting portion 46a so that the upper end of the cylindrical portion 11 is received And a washer 51a accommodated in the valve shaft 34 and disposed so as to be in tight contact with the ends of the compression springs 35a and 35b, (40a).

However, in the case of the conventional pressure relief valve, if the set pressure is not reached, the pressure vessel is not opened and the pressure vessel is not exposed to the fire, There is a problem that it can cause additional accidents.

FIG. 2 is a graph showing a decrease in yield strength when a fire occurs, and FIG. 3 is a graph showing a decrease in elastic modulus when a fire occurs.

Referring to FIGS. 2 and 3 together, a graph is shown in which the yield strength and modulus of elasticity decrease with increasing temperature. In each graph, the X axis represents the temperature and the Y axis represents the normalized intensity value.

Ⅰ and Ⅱ show the steel with different yield strength, respectively, and Ⅲ shows the modulus of elasticity versus load.

The yield strength of Ⅰ is better than the yield strength of Ⅱ, and as the temperature rises, the yield strength of steel is lowered, and the yield strength is lowered even at a small load, so that the structural stiffness is lowered.

4 is a graph showing the strength of the ship when a fire occurs.

Referring to FIG. 4, the X axis represents time, the left Y axis represents intensity, and the right Y axis represents temperature.

V represents Ultimate Tensile Strength (UTS), VI represents the calculated strength, VII represents the maximum average temperature, and VIII represents the maximum tensile strength.

When the fire occurs, the temperature rises to about 950 degrees. As the temperature rises, the strength of the pressure vessel decreases, and the pressure rises and the pressure vessel stress rises.

After 13 hours, the pressure vessel stress at point A becomes larger than the UTS value, causing a rupture in the pressure vessel.

FIG. 5 is a graph showing the maximum opening rate when a fire occurs.

Referring to FIG. 5 together with FIG. 4, it can be seen that the X axis represents time and the Y axis represents the opening rate, and the pressure relief valve is opened at point B after 20 minutes.

Therefore, in Fig. 4, since the pressure vessel stress is greater than the UTS value in Fig. 4 and the pressure vessel ruptures, the pressure safety valve should preferably be opened 13 minutes before, more preferably 10 minutes before, in order to prevent the pressure rise .

In this way, when the set pressure can not be reached, the pressure safety valve is not opened and the pressure vessel is ruptured. Therefore, additional passive fire protection (PFP) is applied to prevent the pressure vessel rupture due to the temperature rise.

However, the PFP application is difficult to install due to the increase in the weight of the module of the offshore plant and the narrow space, and it is difficult to maintain even if it is installed, and congestion is increased, The use of explosive gas increases the probability of gas leakage, which can cause another problem.

Particularly, the PFP installation causes a problem such as a process delay, which causes a problem of deteriorating process efficiency.

Registered Utility Model Application No. 20-2001-0029348

One embodiment of the present invention is to develop a pressure relief valve that takes temperature rise and pressure rise into consideration, and to provide a ship or an offshore structure including it, in place of the use of PFP.

According to one aspect of the present invention, for a pressure relief valve,

A first body;

A second body coupled to the first body and having a working chamber having an opening therein;

A top cap covering an upper portion of the first body;

A first bar provided in the space between the first body and the top cap;

A second bar connected to the first bar;

An opening / closing unit that opens and closes at a lower end of the second bar in accordance with a pressure inside the container; And

A spring coupled to the first and second bars to apply elasticity to the opening and closing portions;

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The opening / closing part may include an open side where one side is opened.

The open face may be made of a bimetal material.

The open side may be made of a metal whose inner side has a relatively higher thermal expansion coefficient than the outer side.

The open face can be opened in proportion to the pressure inside the container.

The opening angle of the open face is preferably PL ³ / (6EI).

The safety valve may further include a first sealing member that seals between the first body and the top cap.

The first hermetically sealed structure may have a structure in which a hole through which the first bar passes is perforated.

And a spring is fixed to a lower portion of the first hermetically sealed part.

The safety valve may further include a second sealing member that seals between the first body and the second body.

The second sealing member may have a structure in which a hole penetrating through the second bar is perforated.

And an opening through which gas or fluid is discharged may be formed on one side of the second body.

According to another aspect of the present invention, a vessel or an offshore structure including the pressure relief valve may be provided.

According to one embodiment of the present invention, the pressure relief valve can improve the safety by adjusting the pressure in consideration of the temperature rise.

In addition, it is possible to minimize or eliminate PFP application, thereby improving load reduction and space efficiency, and improving process efficiency.

1 is a schematic partial cross-sectional view of a conventional pressure relief valve.
2 is a graph showing a decrease in yield strength in the event of a fire.
3 is a graph showing a decrease in elastic modulus when a fire occurs.
4 is a graph showing the strength of a ship when a fire occurs.
5 is a graph showing the maximum opening rate when a fire occurs.
6 is a schematic view showing the principle of a bimetal according to one embodiment of the present invention.
7 is a schematic partial cross-sectional view of a pressure relief valve according to the principle of FIG.
8 is a schematic partial cross-sectional view of a safety valve according to an embodiment of the present invention when a fire occurs.

Various embodiments of the present invention will now be described by way of specific embodiments shown in the accompanying drawings. The differences in the embodiments of the present invention described below are to be understood as mutually exclusive. That is, the specific shapes, structures, and characteristics described may be implemented in other embodiments in accordance with one embodiment, without departing from the spirit and scope of the present invention, It is to be understood that the arrangements may be altered, where like reference numerals refer to like or similar features throughout the several views, and length and area, thickness, and the like may be exaggerated for convenience.

FIG. 6 is a schematic view showing the principle of a bimetal according to one embodiment of the present invention.

Referring to FIG. 6, the metal C, which receives a large amount of thermal energy, expands prior to the metal D using two metals C and D having different thermal expansion coefficients, and the pressure safety valve is opened as the temperature rises .

7 is a schematic partial cross-sectional view of a pressure relief valve in accordance with the principles of FIG. 6, and FIG. 8 is a schematic partial cross-sectional view of a safety valve in accordance with one embodiment of the present invention.

7 and 8, the pressure safety valve 100 includes a first body 111, a second body 112, a top cap 120, a first bar 131, a second bar 132, An opening / closing part 140, and a spring 150.

The second body 112 is formed with a working chamber 114 coupled to the first body 111 and having an opening therein.

The top cap 120 covers and seals the top of the first main body 111.

The first bar 131 is provided in the inner space of the first body 111 and the top cap 120.

The second bar 132 is connected to the lower end of the first bar 131.

The opening and closing part 140 is opened and closed at the lower end of the second bar 132 in accordance with the pressure inside the container.

The opening / closing part 140 includes an opening 141 whose one side opens in the lateral direction.

The opening 141 is made of a bimetallic material and the inner side surface 143 is made of a metal having a thermal expansion coefficient relatively higher than that of the outer side surface 144.

The opening face 141 is opened in proportion to the inner pressure of the container, and the opening angle? Of the opening face 141 is PL ³ / (6EI).

Where P = pressure vessel pressure, L = bimetallic length, E = metal elastic modulus, and I = bimetallic second order moment of inertia.

The spring 150 is coupled to the first bar 131 and the second bar 132 to apply elasticity to the opening and closing part 140.

The spring 150 is fixed to the lower portion of the first closing port 161 and is extended by the second bar 132.

The first hermetic seal 161 seals between the first body 111 and the top cap 120 and the second hermetic seal 162 seals between the first body 111 and the second body 112 .

A hole 165 through which the first bar 131 penetrates is formed in the first closing hole 161 and a hole 166 through which the second bar 132 passes is formed in the second closing hole 162, .

7 and 8, the pressure relief valve 100 is heated by the high-temperature and high-pressure gas when the inside of the pressure vessel is heated by the fire, by describing the operation relationship according to one embodiment of the present invention.

The high-temperature and high-pressure gas heats and presses one opening face 141 of the opening / closing part 140 located at the lower end of the second bar 132.

The inner surface 141 of the opening 141 is expanded first because the inner surface 141 is made of a bimetal metal having a thermal expansion coefficient relatively higher than that of the outer surface 144.

When the inner surface 143 of the opening 141 is relatively expanded relative to the outer surface 144 and the opening 141 is opened at a predetermined angle θ, The pressure vessel is prevented from being ruptured due to the reduction of the structural strength by discharging it to the operating chamber 114 inside the main body 112. When the predetermined temperature is reached, the opening and closing part 140 in the first main body 111 is pressed do.

The second bar 132 connected to the upper end of the opening and closing part 140 is pressed in the vertical direction so that the first bar 131 is moved in the vertical direction by the first body 111 and the top cap 120 so that the opening and closing part 140 is opened upward so that the heated liquid inside the container is discharged through the opening 116 of the second main body 112.

Therefore, even if the conventional pressure relief valve does not reach the set pressure, the problem of the rupture in the pressure vessel due to the decrease in the strength of the pressure vessel due to the temperature rise is solved to improve the overall safety while reducing the load and space efficiency have.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Deletion, addition or the like of the present invention may be variously modified and changed, and this also falls within the scope of the present invention.

100: pressure safety valve 111: first main body
112: second main body 114: operating room
116: opening 120: top cap
131: 1st bar 132: 2nd bar
140: opening / closing part 141: opening face
143: inner side 144: outer side
150: spring 161: first seal
162: second seal 165, 166: holes

Claims (13)

In a pressure relief valve,
A first body;
A second body coupled to the first body and having a working chamber having an opening therein;
A top cap covering an upper portion of the first body;
A first bar provided in an inner space of the first body and the top cap;
A second bar connected to the first bar;
An opening / closing unit that opens and closes at a lower end of the second bar in accordance with a pressure inside the container; And
A spring coupled to the first and second bars to apply elasticity to the opening and closing portions;
And a pressure-relief valve. The method according to claim 1,
Wherein the opening / closing part includes an opening that opens at one side thereof. 3. The method of claim 2,
Wherein the opening is made of bimetallic material. 3. The method of claim 2,
Wherein the open side is made of a metal whose inner side is relatively higher in thermal expansion coefficient than the outer side. 3. The method of claim 2,
Wherein the opening is opened in proportion to the pressure inside the container. 3. The method of claim 2,
And the opening angle of the opening face is PL ³ / (6EI). The method according to claim 1,
Wherein the safety valve further comprises a first sealing member that seals between the first body and the top cap. 8. The method of claim 7,
Wherein the first sealing member is formed with a hole through which the first bar passes. 8. The method of claim 7,
And a spring is fixed to a lower portion of the first hermetic seal. The method according to claim 1,
Wherein the safety valve further comprises a second hermetic seal for sealing between the first body and the second body. 11. The method of claim 10,
Wherein the second sealing member is formed with a hole penetrating through the second bar. The method according to claim 1,
And an opening through which gas or fluid is discharged is formed at one side of the second body. A ship or offshore structure comprising a pressure relief valve according to paragraph 1 or 12.

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