A regulating valve

Abstract

This invention discloses a regulating valve, comprising a valve body and a valve cover. Three pressure chambers are located between the valve body and the valve cover: a pre-valve chamber, a post-valve chamber, and a balancing chamber. The balancing chamber is positioned between the pre-valve chamber and the post-valve chamber. A pilot-operated valve internal is also installed between the valve body and the valve cover. The pilot-operated valve internal includes an upper sleeve, a lower sleeve, a valve seat, a small valve core, and a valve plug. The upper sleeve, lower sleeve, and valve seat are all fixedly installed within the balancing chamber. The upper sleeve has an overflow hole, and the lower sleeve has a flow characteristic control window. The valve plug is installed in a suspended manner within the balancing chamber. A spring tension sealing ring that cooperates with the valve plug is also installed between the upper and lower sleeves. The valve plug has an auxiliary fluid passage, and the small valve core is movably connected to the middle of the valve plug. The valve body also has two fluid channels.

Description

Technical Field

[0001] This invention belongs to the field of regulating valve technology and relates to a regulating valve. Background Technology

[0002] Liquefied natural gas (LNG) control valves face numerous challenges under complex operating conditions such as ultra-low temperatures, high pressures, large pressure differentials, and large diameters. Specific operating characteristics are as follows: The medium handled is LNG, and the operating conditions exhibit significant characteristics of ultra-low temperatures (-155℃), high pressures (11.5MPa), large pressure differentials (15.4MPa), and large diameters (DN250mm), making it a complex and demanding type of operation. Structurally, the valve must withstand the effects of freezing temperatures and thermal expansion and contraction on its dimensions. Furthermore, to prevent movement jamming due to thermal deformation, a large clearance exists between the valve plug and the sleeve, which reduces the valve plug's guiding performance. Therefore, the alignment of the valve plug and valve seat sealing surfaces must be effectively ensured. Regarding the force exerted by the medium, under conditions of large diameter, high pressure, and high pressure differential, the medium generates enormous forces. To ensure normal operation of the control valve, the operating force of the actuator must be reduced. Regarding the risk of cavitation damage, the low-temperature, high-pressure medium is highly susceptible to vaporization (phase change) during throttling and depressurization, leading to strong cavitation effects (internal vaporization, cavitation). Regarding the stringent shut-off requirements, the control valve needs to achieve tight shut-off under low temperature and high pressure environments to ensure complete valve closure and provide sufficient sealing pressure. In summary, designing a control valve to solve these problems is of significant practical importance and necessity. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a regulating valve.

[0004] To achieve the above objectives, the technical solution of the present invention is: a regulating valve, comprising a valve body and a valve cover, wherein three pressure chambers are provided between the valve body and the valve cover, namely a pre-valve chamber, a post-valve chamber, and a balance chamber, and the balance chamber is disposed between the pre-valve chamber and the post-valve chamber; a pilot-operated valve internal component is also installed between the valve body and the valve cover, the pilot-operated valve internal component comprising an upper sleeve, a lower sleeve, a valve seat, a small valve core, and a valve plug; the upper sleeve, lower sleeve, and valve seat are all fixedly installed in the balance chamber, and the upper sleeve, lower sleeve, and valve seat are arranged sequentially from top to bottom; the upper sleeve has an overflow hole, the lower sleeve has a flow characteristic control window, and the valve plug is installed in the balance chamber in a suspended installation manner, with the valve plug... The upper and lower sleeves are adjusted to change the flow area exposed by the flow characteristic control window, thereby achieving flow control. A spring tension sealing ring that cooperates with the valve plug is also installed between the upper and lower sleeves. The valve plug has an auxiliary fluid passage. The small valve core is movably connected to the middle of the valve plug and can move up and down relative to the valve plug. A spring is also provided between the small valve core and the valve plug. The opening and closing of the auxiliary fluid passage is controlled by the up and down movement of the small valve core. The valve body also has two fluid channels. The main fluid channel goes from the valve front chamber through the sealing surface of the valve seat to the valve rear chamber. The auxiliary fluid channel goes from the valve front chamber through the overflow hole to the balance chamber, and then through the sealing surface of the small valve seat to the valve rear chamber.

[0005] A metal winding ring is provided between the valve cover and the upper sleeve, and between the upper sleeve and the lower sleeve.

[0006] The metal winding ring is made of multi-layered, wave-shaped stainless steel sheet.

[0007] The sealing surface of the valve seat is a conical surface, and the surface on which the valve plug mates with the valve seat is a spherical surface.

[0008] The sealing surface of the valve plug is a conical surface, and the surface on which the small valve core mates with the valve plug is a spherical surface.

[0009] The spring tension sealing ring adopts a structure with a built-in pre-tightened H-type spring.

[0010] The valve cover has an elongated top cover.

[0011] The valve cover is also connected to a valve stem for driving the movement of the small valve core, and a valve position indicator is installed on the valve stem.

[0012] The valve seat has a main fluid passage.

[0013] The lower sleeve, valve seat, and valve plug all use small-hole channels.

[0014] The small-hole channel is composed of several evenly distributed small holes.

[0015] By adopting the above technical solution, the beneficial effects of the present invention are: 1. Pressure balance and thrust optimization: The internal components adopt a pressure balance cage structure, combined with the pilot design of the valve plug. By switching between pressure balance and unbalanced states, the force of the medium and the thrust of the actuator are effectively reduced, solving the sealing pressure problem under large diameter, high pressure and large pressure difference.

[0016] 2. Low temperature environment adaptability: The elongated top cover design keeps the upper packing in a normal temperature environment, avoiding freezing and ensuring normal valve stem operation.

[0017] 3. Anti-cavitation and noise reduction design: The small-hole flow channel forms a multi-stage pressure reduction, which has the functions of anti-cavitation, noise reduction and vibration reduction.

[0018] 4. Improved sealing performance: In the conical + spherical sealing pair, the floating compensation of the spherical surface can make up for the insufficient sealing surface fit rate caused by the fit error, and improve the sealing cut-off effectiveness; the metal winding ring compensates for the axial dimension change caused by temperature through the change of compression, keeping the valve internals stable and not loose.

[0019] 5. Visual monitoring and control: The valve position indicator installed on the valve stem can display the valve plug position in real time, realizing visual monitoring and precise control of the valve opening, which makes it easy for operators to quickly judge the working status. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the planar structure of the present invention; Figure 2 This is a schematic diagram of a partial location of the present invention; Figure 3 This is a magnified view of a section at point C; Figure 4 This is a magnified view of a portion at point D; Figure 5 This is a magnified view of a section at point E; Figure 6 This is a magnified view of a section at point F; Figure 7 This is a magnified view of a portion of point G; Figure 8 This is a magnified view of a portion at point H; In the diagram, 1 is the valve body; 3 is the valve seat; 3a is the main fluid passage; 4 is the lower sleeve; 4a is the flow characteristic control window; 5 is the upper sleeve; 5a is the overflow hole; 6 is the valve cover; 6a is the extended upper cover; 9 is the valve stem; 16 is the packing; 21 is the spring; 22 is the small valve core; 23 is the valve plug; 23a is the auxiliary fluid passage; 24 is the metal spiral wound ring; 26 is the spring tension sealing ring; and 27 is the valve position indicator. Detailed Implementation

[0021] To further explain the technical solution of the present invention, the present invention will be described in detail below through specific embodiments.

[0022] like Figure 1-8 As shown, this regulating valve includes a valve body 1 and a valve cover 6. There are three pressure chambers between the valve body 1 and the valve cover 6: a pre-valve chamber, a post-valve chamber, and a balance chamber. The balance chamber is located between the pre-valve chamber and the post-valve chamber. In a balanced state, the post-valve chamber is connected to the balance chamber to reduce the unbalanced area of ​​the medium, greatly reducing the force of the medium and significantly reducing the thrust of the actuator. A pilot-operated valve internal is also installed between the valve body 1 and the valve cover 6. The pilot-operated valve internal includes an upper sleeve 5, a lower sleeve 4, a valve seat 3, a small valve core 22, and a valve plug 23. Specifically: the valve... The seat 3 has a main fluid passage 3a; the upper sleeve 5, lower sleeve 4, and valve seat 3 are all fixedly installed in the balance chamber, and the upper sleeve 5, lower sleeve 4, and valve seat 3 are arranged sequentially from top to bottom. The upper sleeve 5 has an overflow hole 5a, and the lower sleeve 4 has a flow characteristic control window 4a. The valve plug 23 is installed in the balance chamber in a suspended manner. The flow area exposed by the flow characteristic control window 4a on the lower sleeve 4 is adjusted by the up and down movement of the valve plug 23 to achieve flow control; a valve plug 23 is also installed between the upper sleeve 5 and the lower sleeve 4. The spring tension sealing ring 26 is matched accordingly. Due to the large gap between the upper sleeve 5, lower sleeve 4 and valve plug 23 after assembly, the valve plug 23 is in a suspended state. The spring tension sealing ring 26 eliminates the gap between the upper sleeve 5, lower sleeve 4 and valve plug 23, ensuring positioning accuracy. When the valve plug 23 is closed downwards, it can effectively ensure the alignment of the sealing surface of the valve seat 3, making the sealing performance more reliable. When the medium undergoes a phase change and forms an alternating force acting on the valve plug 23, the spring tension sealing ring 26 can act as a damping element, effectively suppressing the vibration of the valve plug 23. The valve plug 23 has an auxiliary fluid passage 23a. The small valve core 22 is movably connected to the middle of the valve plug 23 and can move up and down relative to the valve plug 23. A spring 21 is also provided between the small valve core 22 and the valve plug 23. The opening and closing of the auxiliary fluid passage 23a is controlled by the up and down movement of the small valve core 22. The valve body 1 also has two fluid channels. The main fluid channel goes from the valve front chamber through the sealing surface of the valve seat 3 to the valve rear chamber. The auxiliary fluid channel goes from the valve front chamber through the overflow hole 5a to the balance chamber, and then through the sealing surface of the small valve seat 3 to the valve rear chamber.

[0023] A metal spiral wound ring 24 is installed between the valve cover 6 and the upper sleeve 5, and between the upper sleeve 5 and the lower sleeve 4. Because the medium is in an ultra-low temperature state, and the valve is processed and assembled at room temperature, drastic temperature changes after commissioning will cause changes in component dimensions. Simultaneously, there is a temperature difference between the valve body 1 and the valve internals, resulting in different amounts of thermal expansion and contraction. This can lead to axial loosening or thermal deformation of the upper sleeve 5 and lower sleeve 4 within the valve. Due to the large amplitude and significant amount of temperature changes, the metal spiral wound ring 24 can compensate for dimensional changes by adjusting its own compression and always maintain sufficient elasticity to prevent loosening of the valve internals. Adding two metal spiral wound rings 24 further adapts to such large temperature changes.

[0024] The metal winding ring 24 is made of a corrugated, multi-layered stainless steel sheet that generates elasticity under compression, thus fixing the upper sleeve 5 and the lower sleeve 4.

[0025] The sealing surface of valve seat 3 is a conical surface, and the surface of valve plug 23 that mates with valve seat 3 is a spherical surface; the sealing surface of valve plug 23 is a conical surface, and the surface of small valve core 22 that mates with valve plug 23 is a spherical surface; the spherical surface has floating compensation properties, which can compensate for insufficient sealing surface contact rate caused by fitting errors when the sealing pair is closed, thus improving the effectiveness of sealing and cutting off. Meanwhile, in practice, all sealing surfaces are overlaid with hard alloy, thereby giving them resistance to erosion and cavitation; such as Figure 7 and 8 As shown.

[0026] The spring tension sealing ring 26 adopts a built-in pre-tightened H-type spring structure, which relatively fixes the valve plug 23.

[0027] The valve cover 6 has an elongated top cover 6a. When the low temperature liquid is transferred upward, the temperature of the elongated top cover 6a gradually increases as it extends upward, so that the upper packing 16 is kept at room temperature and does not freeze. This ensures that the valve stem 9 will not freeze and can operate normally.

[0028] A valve stem 9 for driving the small valve core 22 is also connected to the valve cover 6, and a valve position indicator 27 is installed on the valve stem 9.

[0029] The lower sleeve 4, valve seat 3, and valve plug 23 all use small-hole channels, which can increase flow resistance and reduce pressure and flow velocity, reduce the generation of low-temperature liquid phase change, and reduce cavitation damage. Since the small holes share most of the medium pressure, the pressure acting on the sealing surface is small, the medium cavitation damage is small, and the reliability and durability of the seal are guaranteed. The small-hole channel is composed of several uniformly distributed small holes. The uniform distribution of small holes makes the complex fluid after the medium phase change more uniform, reduces the generation of eddies, and makes the fluid acting on the valve plug 23 more uniform and stable, reducing the generation of vibration sources.

[0030] The above structure allows the valve to switch between pressure balance and pressure imbalance during opening and closing.

[0031] When closing downwards: the small valve core 22 is transmitted to the valve plug 23 through the spring 21 and moves to the sealing surface of the valve seat 3, closing the main fluid passage. After that, the small valve core 22 continues to compress the spring 21 downwards until it is in complete contact with the sealing surface on the valve plug 23, closing the auxiliary fluid passage.

[0032] At this time, the valve internals are in a pressure-unbalanced state, with the medium pressure in the balancing chamber being the same as the pressure in the upstream chamber. The sealing surface of valve seat 3 achieves a tight seal under the combined action of the actuator thrust and the medium pressure. This effectively solves the sealing pressure problem under conditions of large diameter, high pressure, large pressure differential, and tight shut-off, and significantly reduces the actuator thrust.

[0033] When the valve is opened upwards: the small valve core 22 moves upwards, opening the sealing surface of the valve seat 3. At this time, the balance chamber and the valve rear chamber are in communication. Since the area of ​​the auxiliary fluid passage 23a of the valve seat 3 is much larger than that of the overflow hole 5a, the pressure in the balance chamber is relieved. At this time, the valve internals become pressure balanced, and the small valve core 22 drives the valve plug 23 to make adjustment movements with a small operating force.

[0034] After the valve is opened, the small valve seat 3 remains open under the action of the spring 21, maintaining a pressure balance state.

[0035] In the pilot-operated structure, the two sealing surfaces close sequentially without interference, ensuring effective sealing during the sealing process. The specific sealing surfaces mentioned can be found in [reference needed]. Figure 7 and 8 .

[0036] In summary, this invention addresses the complex operating conditions of liquefied natural gas (LNG) under ultra-low temperature, high pressure, large pressure differential, and large diameter conditions. Through the system integration of a pressure-balanced cage structure, a pilot structure, a small-orifice pressure-reducing flow channel, and a combined sleeve, it achieves comprehensive performance goals of low operating force, cavitation resistance, low vibration, and tight shut-off, providing an effective technical solution for key valves in LNG storage and transportation systems.

[0037] In practical applications, the entire regulating valve is as follows: Figure 1 As shown in the figure, the handwheel used to drive the valve stem 9 to rotate is omitted.

[0038] All of the above components are general standard parts or components known to those skilled in the art. Their structure and principles can be learned by those skilled in the art through technical manuals or conventional experimental methods.

[0039] The above embodiments and figures are not intended to limit the product form and style of the present invention. Any appropriate changes or modifications made by those skilled in the art should be considered as not departing from the patent scope of the present invention.

Claims

1. A regulating valve, comprising a valve body (1) and a valve cover (6), wherein the valve body (1) and the valve cover (6) have three pressure chambers, namely a pre-valve chamber, a post-valve chamber, and a balancing chamber, and the balancing chamber is disposed between the pre-valve chamber and the post-valve chamber, characterized in that, A pilot-operated valve internal is installed between the valve body (1) and the valve cover (6). The pilot-operated valve internal includes an upper sleeve (5), a lower sleeve (4), a valve seat (3), a small valve core (22), and a valve plug (23). The upper sleeve (5), the lower sleeve (4), and the valve seat (3) are all fixedly installed in the balance chamber, and the upper sleeve (5), the lower sleeve (4), and the valve seat (3) are arranged sequentially from top to bottom. The upper sleeve (5) has an overflow hole (5a), and the lower sleeve (4) has a flow characteristic control window (4a). The valve plug (23) is installed in the balance chamber in a suspended installation manner. The flow area exposed by the flow characteristic control window (4a) on the lower sleeve (4) is adjusted by the up and down movement of the valve plug (23) to achieve flow control. A spring tension sealing ring (26) that cooperates with the valve plug (23) is also installed between the sleeve (5) and the lower sleeve (4); the valve plug (23) has an auxiliary fluid passage (23a), the small valve core (22) is movably connected to the middle of the valve plug (23), and the small valve core (22) can move up and down relative to the valve plug (23). A spring (21) is also provided between the small valve core (22) and the valve plug (23), and the opening and closing of the auxiliary fluid passage (23a) is controlled by the up and down movement of the small valve core (22); the valve body (1) also has two fluid channels. The main fluid channel goes from the valve front cavity through the sealing surface of the valve seat (3) to the valve rear cavity; the auxiliary fluid channel goes from the valve front cavity through the overflow hole (5a) to the balance cavity, and then through the sealing surface of the small valve seat (3) to the valve rear cavity.

2. The pilot-operated valve internals of a regulating valve according to claim 1, characterized in that, The valve cover (6) is also connected to a valve stem (9) for driving the small valve core (22) to move, and a valve position indicator (27) is installed on the valve stem (9).

3. The pilot-operated valve internals of a regulating valve according to claim 1, characterized in that, A metal winding ring (24) is provided between the valve cover (6) and the upper sleeve (5), and between the upper sleeve (5) and the lower sleeve (4).

4. The pilot-operated valve internals of a regulating valve according to claim 3, characterized in that, The metal winding ring (24) is made of a wavy, multi-layered stainless steel sheet.

5. The pilot-operated valve internals of a regulating valve according to claim 1, characterized in that, The sealing surface of the valve seat (3) is a conical surface, and the surface on which the valve plug (23) mates with the valve seat (3) is a spherical surface.

6. The pilot-operated valve internals of a regulating valve according to claim 5, characterized in that, The sealing surface of the valve plug (23) is a conical surface, and the surface on which the small valve core (22) and the valve plug (23) cooperate is a spherical surface.

7. The pilot-operated valve internals of a regulating valve according to claim 1, characterized in that, The spring tension sealing ring (26) adopts a structure with a built-in pre-tightened H-type spring.

8. The pilot-operated valve internals of a regulating valve according to claim 1, characterized in that, The valve cover (6) has an elongated top cover (6a).

9. The pilot-operated valve internals of a regulating valve according to claim 1, characterized in that, The valve seat (3) has a main fluid passage (3a).

Images