CN115681580A - Safe pressure relief device of ultra-high accuracy - Google Patents
Safe pressure relief device of ultra-high accuracy Download PDFInfo
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- CN115681580A CN115681580A CN202211083300.1A CN202211083300A CN115681580A CN 115681580 A CN115681580 A CN 115681580A CN 202211083300 A CN202211083300 A CN 202211083300A CN 115681580 A CN115681580 A CN 115681580A
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Abstract
The invention discloses an ultra-high precision safety pressure relief device, which comprises: the main valve body, the valve core assembly in the main valve body, one end of the valve core assembly is connected with the pressure adjusting nut through a spring, the other end of the valve core assembly is connected with the medium inlet, the small end face of the valve core and the large end face of the valve core are positioned on the valve core assembly, the valve core sealing gasket is radially sleeved on the small end face of the valve core, and the pressure sensing channel is communicated with the large end face of the valve core and the medium inlet. By reducing the opening and closing pressure difference, namely, the recoil pressure is closer to the setting pressure value, the pressure stabilization precision of the equipment can be greatly improved, and the amount of medium discharge loss can be reduced, so that the economy can be improved; meanwhile, the environmental protection problem possibly caused by certain greenhouse effect gases due to more media discharged by pressure relief caused by large opening and closing pressure difference is avoided; in addition, the frequency and the amplitude of the alternate pressure change of the pressure container and the pipeline are objectively reduced, and the fatigue times caused by the alternate pressure are reduced to a certain extent, so that the service lives of all pressure-bearing parts in the whole system can be effectively protected and prolonged.
Description
Technical Field
The invention relates to the technical field of pressure control and adjustment, in particular to an ultra-high-precision safety pressure relief device.
Background
When the pressure in the equipment or the pipeline exceeds the set pressure of the pressure relief device, the pressure relief device is automatically started to relieve pressure, the medium pressure in the equipment and the pipeline is ensured to be below the set pressure, the equipment and the pipeline are protected, and accidents are prevented. The pressure relief device can be automatically opened and closed according to the working pressure of the system, and is generally arranged on equipment or a pipeline of a pressure bearing system to protect the safety of the system.
In some applications where the requirements are relatively high, it is desirable to have the cracking pressure and the recoil pressure of the pressure vessel or pressure line as close as possible. For example, in the field of semiconductors and the like, the pressure in a pipeline is required to be kept constant, and the process stability is influenced by an overlarge pressure fluctuation value.
According to the regulations of the national standard GB12241-2005 safety valve general requirements, the traditional safety pressure relief device has the pressure difference between the set pressure and the recoil pressure for the incompressible medium, namely, the maximum value of the opening and closing pressure difference is 20% of the set pressure, and the set pressure is the set opening pressure value. Obviously, the opening and closing pressure difference set by the national standard is large, and the requirements of severe special occasions are difficult to meet. Aiming at the occasions with high standards and requirements, a pressure sensor and an electromagnetic switch valve are mostly adopted at present to realize the accurate control of the pressure. The disadvantages of this are two:
1. electromagnetic valves, pressure sensors, and the like, resulting in a substantial increase in equipment costs;
2. under the conditions of unexpected power failure and the like, the electromagnetic valve fails, so that the system is exposed to the risk that the safety pressure relief device cannot work normally;
in addition, the larger the opening and closing pressure difference is, namely the farther the recoil pressure value is from the setting pressure value, the more the discharged medium is, the larger the loss is, the worse the economy is, the environmental protection problem can be brought by medium discharge, and the cost of enterprise application is also indirectly increased.
Disclosure of Invention
The invention aims to: the invention aims to solve the defects of the prior art and provides an ultra-high precision safety pressure relief device, which comprises: the main valve body, the valve core assembly located in the main valve body, one end of the valve core assembly are connected with the pressure regulating nut through a spring, the other end of the valve core assembly is connected with the medium inlet, the small end face of the valve core and the large end face of the valve core which are located on the valve core assembly, the valve core sealing gasket which is radially sleeved on the small end face of the valve core and the pressure sensing channel which connects the large end face of the valve core and the medium inlet;
the sum of the areas of the small end surface of the valve core and the large end surface of the valve core is the same as the radial area of the valve core assembly;
the main valve body is provided with a medium discharge port, and the valve core assembly moves axially in the main valve body to realize the connection or disconnection of the medium discharge port and the medium inlet port;
after the pressure relief device is installed in a container, when the pressure in the container is obviously lower than a pressure set value or a set pressure value of the safety pressure relief device, the spring force of a spring is greater than the medium pressure resultant force, a valve core sealing gasket presses a sealing surface of a valve body rightwards, and the safety pressure relief device is in a closed state; the medium enters from the medium inlet at the moment and enters the closed inner cavity filled with the right side of the large end face of the valve core through the pressure sensing channel, and the pressure of the inner cavity is equal to the pressure of the medium inlet;
when the pressure in the container rises, the resultant force of the pressure of the medium is larger than the sum of the spring force and the friction force, the valve core assembly moves leftwards, the spring is compressed, the spring force rises, the sealing ring leaves the sealing surface of the valve body, the medium in the storage tank begins to be released outwards from the medium release port, and if the releasing speed is larger than the rising speed of the pressure in the storage tank, the pressure in the storage tank is reduced along with releasing;
the control of opening and closing differential pressure is realized by adjusting the area ratio of the small end surface of the valve core to the large end surface of the valve core.
As a further preferable mode of the present invention, the large end surface of the valve core is annular, the right side of the large end surface of the valve core is a closed inner cavity, and the pressure at the inner cavity is equal to the pressure at the medium inlet.
As further optimization of the invention, the section of the valve core assembly is in a T shape, the small end surface and the large end surface of the valve core are arranged in a ladder shape, the area ratio of the small end surface and the large end surface of the valve core is controllable, and finally controllable opening and closing pressure difference is obtained.
As a further preference of the invention, the contact surfaces of the small end surface and the large end surface of the valve core and the main valve body are respectively provided with a support ring, and the support rings are additionally arranged, so that the tightness of the contact surfaces of the small end surface and the large end surface of the valve core and the main valve body is ensured, and the working reliability of the valve core assembly is ensured.
As a further preferred aspect of the present invention, the opening and closing pressure difference is:
wherein, P S Is a set pressure value, P, in the technical scheme B Is the container reseating pressure value, P, in the technical scheme B ' is the value of the container reseating pressure in the prior art, S X Is the area of the small end face of the valve core, S D Is the total radial area of the valve core.
As a further preferred feature of the present invention, the medium inlet is connected to a pressure vessel or a pressure pipe.
As a further preferred aspect of the present invention, a protective sleeve is sleeved on the radial outer side of the main valve body, and the small valve element end face, the large valve element end face and the spring are located on one side of the main valve body close to the protective sleeve. The protective sheath is used for preventing water vapor dust foreign matter acid rain etc. guarantees that core components such as inside spring do not receive the influence of environment and impurity.
Has the beneficial effects that: compared with the prior art, the ultra-high precision safety pressure relief device has the following advantages:
(1) The deviation between the recoil pressure value and the standard pressure value is controllable, so that the pressure stability precision of the equipment can be greatly improved, and the opening and closing pressure difference is reduced to 5% from the maximum 20% of the national standard;
(2) The medium discharge loss is reduced, the loss is reduced, and the environmental protection pressure is reduced, so that the application cost is reduced;
(3) The frequency and the amplitude of the pressure change of the pressure container and the pipeline are reduced, and the fatigue times caused by the alternative pressure are reduced to a certain extent, so that the service lives of all pressure-bearing parts in the whole system can be effectively protected and prolonged, and the pressure-bearing device comprises a storage tank, a pipeline, a valve, a pressure gauge, a flowmeter and the like.
Drawings
FIG. 1 is a full sectional view of a prior art pressure relief;
FIG. 2 is a cross-sectional view of an open state of a pressure relief valve in the prior art;
FIG. 3 is a full sectional view of the present invention;
FIG. 4 is a full sectional view of the present invention in a pressure relief state;
FIG. 5 is a partial cross-sectional view of the present invention;
FIG. 6 is an enlarged view of a portion of the sealing surface of the valve body.
Detailed Description
The invention will be further elucidated with reference to the drawing.
As shown in fig. 1 and fig. 2, cross-sectional views of a pressure relief valve in the prior art are shown, a maximum value of an opening/closing differential pressure in the prior art is 20% of a set pressure, and the set pressure is a set opening pressure value. This results in a large amount of discharged media, high loss, poor economy, and increased cost of environmental pollution control.
Fig. 3 shows an ultra-high precision safety pressure relief device according to the present invention, which comprises: the valve comprises a main valve body 1, a protective sleeve 2, a valve core assembly 3, a spring 4, a pressure adjusting screw 5, a support ring 6, a valve core sealing gasket 7, a medium inlet 8, a pressure sensing channel 9 and a medium discharge port 10;
the valve core assembly 3 is arranged in the main valve body 1 in a penetrating mode, one end of the valve core assembly 3 is connected with the pressure adjusting nut 5 through the spring 4, the other end of the valve core assembly 3 is connected with a medium inlet port 8 located at the end of the main valve body 1, a valve core small end face 31 and a valve core large end face 32 are coaxially arranged on the valve core assembly 3, a valve core sealing gasket 7 is radially sleeved on the valve core small end face 31 and abuts against a valve body sealing face 71, and the medium inlet port 8 is communicated with the valve core large end face 32 through a pressure sensing channel 9.
Examples
If the pressure in the container rises, so that the resultant force of the pressure of the medium is larger than the sum of the spring force and the friction force, the valve core assembly 3 moves leftwards, and meanwhile, the spring 4 is compressed, so that the spring force rises; at the same time, the sealing gasket 7 is separated from the sealing surface 71 of the valve body, so that the medium in the storage tank begins to be discharged outwards from the medium discharge port 10, as shown in fig. 4, 5 and 6. If the medium discharge speed is higher than the pressure rise speed in the storage tank, the pressure in the storage tank is reduced along with discharge;
when the pressure in the storage tank gradually drops and is lower than a set safety pressure value along with the opening and the release of the safety pressure relief device, the spring force is greater than the resultant force of the medium pressure, and the safety pressure relief device is closed again;
when the resultant force of the spring force and the medium pressure is in an unbalanced state, the valve core assembly 3 is in a sliding state and can be subjected to sliding friction force, or the valve core assembly 3 is not in motion, the valve core assembly is still in a static state due to the action of static friction force, and then the static friction force plays a balance role in the total stress of the valve core.
Setting the opening pressure of the safety pressure relief device as a set value, at the moment that the valve core sealing gasket 7 and the valve body sealing surface 71 are just in contact but do not generate acting force when the safety pressure relief device returns to the seat after the pressure is reduced from opening pressure relief, if the system pressure is lower than the safety set pressure value, the spring force is greater than the resultant force of the medium pressure and the friction resistance, the valve core assembly 3 is subjected to the rightward resultant force, and continues to move rightwards under the effect of the rightward resultant force, at this moment, the valve core sealing gasket 7 and the valve body sealing surface 71 are tightly pressed and generate certain deformation until the pressure of the valve core sealing gasket 7 on the valve body sealing surface 71 is enough, so that when the medium escape resistance in the container is increased and is not discharged any more, the container pressure value at this moment is the return pressure value.
By adjusting the area ratio of the small end surface 31 and the large end surface 32 of the valve core, the deviation value of the reseating pressure value relative to the standard pressure value is changed, namely the opening and closing pressure difference is obtained according to the following steps:
the aperture of the medium inlet is a fixed value, and the set pressure value is assumed to be P S Assuming a container reseat pressure value of P B Spring force of F in the return-to-seat state B (neglecting the micro-deformation of the sealing gasket), the area of the small end surface 31 of the valve core is S X The total radial area of the valve core assembly 3 is S D ，
In the return-to-seat state, the axial pressing force between the valve core sealing gasket 7 and the valve body sealing surface 71 is F H (axial force is used as a standard value for comparison and measurement), at this time, the valve core assembly 3 is in a static state and has no moving tendency, so that the static friction force is not generated:
F H ＝F B -P B *S D (1)
assuming that the container pressure is just at the standard set pressure value, at this time, the valve core sealing gasket 7 and the valve body sealing surface 71 are in contact with each other theoretically, but the acting force of each other is zero, because the displacement of the spring 4 is equal to the displacement in the reseating state, the difference value of the spring force caused by slight deformation of the valve core sealing gasket 7 is ignored, so the spring force in this state is equal to the spring force in the reseating state:
0＝F B -P S *S D (2)
(1) The formula (2) can be given as follows:
F H ＝(P S -P B )*S D (3)
however, the valve core of the safety relief device in the prior art has no large end and only has one specified relief caliber, so the corresponding area is the area S of the sealing position of the small end of the valve core in the invention X Thus, it is derived from the above that the axial pressing force F between the valve core sealing gasket and the valve body sealing surface in the return seat state in the prior art H ' (compare and measure against axial force as standard) are:
F H ’＝(P S -P B )*S X (4)
due to S D >S X Thus F H >F H ' therefore, the sealing pressing force of the invention is larger, and the proportional relation of the two is that (3) is divided by (4) to obtain:
F H /F H ’＝S D /S X (5)
it can be known from the formula (5) that different pressure values can be realized by adjusting the areas of the valve core small end surface 31 and the valve core large end surface 32. Due to the arrangement, for the safety pressure relief device with the specified rated discharge size, the caliber of a medium inlet is a fixed value, so that the larger the pressing force is, the better the sealing property is with the same sealing caliber. The above derivation is based on the assumption that: the standard set pressure value and the recoil pressure value are fixed and unchangeable values.
If the caliber of a medium inlet of the safety pressure relief device with a specified rated discharge size is a fixed value, and if the sizes of the valve core sealing gaskets 7 are the same and the physical characteristic parameters such as the size, the smoothness and the like of the valve body sealing surface 71 are also the same, the pressing force of the invention and the traditional structure when the back seat effective sealing is realized is theoretically equal, namely F H ＝F H ', then the recoil pressure P of both B And P B ' are not equal:
F H ＝(P S -P B )*S D (6)
F H ＝(P S -P B ’)*S X (7)
the ratio of the deviation value of the standard pressure value from the recoil pressure value can be obtained from the above equations (6) and (7):
comparative experimental data
The product of the invention has been trial-manufactured and tested and verified, the experiment adopts 2.41 MPa setting pressure and adopts a liquid nitrogen Dewar flask provided by Faihouye corporation to test,
this pressure relief device of installation on the dewar bottle, 5 times experimental data show, open and close the pressure differential value and do respectively: 4.9%, 4.8%, 4.9%, 4.95%, 4.85%.
The imported brand of former dress on the dewar bottle, adopt prior art's traditional relief valve, 5 times experimental data show that it is respectively to open and close the pressure differential: 18.9%, 16.8%, 17.9%, 16.9%, 19.8%.
According to the contrast experiment data, the opening and closing pressure difference is reduced to be within 5% from the maximum 20% of the national standard, the opening and closing pressure difference is reduced, the pressure stability precision of the equipment can be greatly improved, the medium discharge loss is reduced, the economy is improved, the environmental protection problem possibly caused by the opening and closing pressure difference is avoided, the frequency and the amplitude of the alternate pressure change of the pressure container and the pipeline are reduced, the fatigue frequency caused by the alternate pressure is reduced to a certain degree, the service life of all pressure-bearing parts in the whole system can be effectively protected and prolonged, and the pressure-bearing device comprises a storage tank, a pipeline, a valve, a pressure gauge, a flowmeter and the like
The above embodiments are merely illustrative of the technical concepts and features of the present invention, and the purpose of the embodiments is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.
Claims (8)
1. An ultra-high precision safety pressure relief device, comprising: the main valve body (1), the case assembly (3) that is located main valve body (1), the one end of case assembly (3) are passed through spring (4) and are connected with pressure adjusting nut (5), and the other end and the medium inlet port (8) of case assembly (3) link to each other, its characterized in that: it still includes: a valve core small end face (31) and a valve core large end face (32) which are positioned on the valve core assembly (3), a valve core sealing gasket (7) which is radially sleeved on the valve core small end face (31), and a pressure sensing channel (9) which connects the valve core large end face (32) with a medium inlet (8);
the sum of the areas of the small end surface (31) and the large end surface (32) of the valve core is the same as the total radial area of the valve core assembly (3);
a medium discharge port (10) is arranged on the main valve body (1), and the valve core assembly (3) moves axially in the main valve body (1) to realize the connection or disconnection of the medium discharge port (10) and the medium inlet port (8);
the control of opening and closing differential pressure is realized by adjusting the area ratio of the small end surface (31) and the large end surface (32) of the valve core.
2. An ultra-high precision safety pressure relief device according to claim 1, wherein: the big end surface (32) of the valve core is annular.
3. The ultra-high precision safety pressure relief device according to claim 1, wherein: the section of the valve core assembly (3) is T-shaped.
4. An ultra-high precision safety pressure relief device according to claim 1, wherein: and support rings (6) are respectively arranged on the contact surfaces of the small end surface (31) and the large end surface (32) of the valve core and the main valve body (1).
5. The ultra-high precision safety pressure relief device according to claim 1, wherein: the opening and closing pressure difference is as follows:
wherein, P S Is a set pressure value in the technical scheme, also called as a setting pressure value, P B Is the container reseating pressure value, P in the technical scheme B ' is the container reseating pressure value, S in the prior art X The area of the small end surface (31) of the valve core is equal to the corresponding area of the pressure born by the valve core in the prior art; s D The total radial area of the valve core is equal to the corresponding area of the pressure born by the valve core in the technical scheme.
6. The ultra-high precision safety pressure relief device according to claim 1, wherein: the medium inlet (8) is connected with a pressure vessel or a pressure pipeline.
7. An ultra-high precision safety pressure relief device according to claim 1, wherein: the radial outer side of the main valve body (1) is sleeved with a protective sleeve (2).
8. The ultra-high precision safety pressure relief device according to claim 1, wherein: the small end face (31) of the valve core, the large end face (32) of the valve core and the spring (4) are positioned on one side, close to the protective sleeve (2), in the main valve body (1).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2022110762059 | 2022-09-05 | ||
| CN202211076205 | 2022-09-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115681580A true CN115681580A (en) | 2023-02-03 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211083300.1A Pending CN115681580A (en) | 2022-09-05 | 2022-09-06 | Safe pressure relief device of ultra-high accuracy |
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| CN (1) | CN115681580A (en) |
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- 2022-09-06 CN CN202211083300.1A patent/CN115681580A/en active Pending
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