Maintenance-free pilot operated safety valve

Abstract

The utility model belongs to valve body technical field especially relates to pilot safety valve, the utility model provides maintenance -free pilot safety valve, include: main valve, pilot valve, the connecting structure of connecting main valve and pilot valve and joint, the connecting structure includes: a plurality of pipe fittings, locking piece is covered in the both ends of pipe fitting, locking piece includes cap nut and extension cylinder, extension cylinder outside is equipped with first thread, and first thread is reverse thread, prevent piece, it is connected with extension cylinder, prevent piece includes stop retreat cylinder, stop retreat cylinder inside is equipped with second thread with extension cylinder outside first thread is adapted, and second thread is reverse thread with first thread rotation direction is contrary, the utility model discloses through setting extension cylinder outside reverse first thread and stop retreat cylinder inside reverse second thread, realized both reverse thread screwing connection, solved the industry pain point that traditional single rotation direction thread cap nut is easy to back off because of vibration load, ensured the long -term fastening of connecting structure.

Description

Technical Field

[0001] This utility model belongs to the field of valve body technology, specifically relating to pilot-operated safety valves, and more particularly to maintenance-free pilot-operated safety valves. Background Technology

[0002] Pilot-operated safety valves sense system pressure and control the main valve's operation through a pilot valve. They have advantages such as high pressure setting accuracy and large discharge capacity, and are widely used in many industries such as petrochemicals, energy and power, and metallurgy.

[0003] In related technologies, the main valve and pilot valve of a pilot-operated safety valve are connected by a pipeline. The nuts used for fastening at the connection point of the pipeline mostly adopt a traditional single-thread structure. However, the industrial environment in which the safety valve is located is often accompanied by high-frequency vibration (such as pump operation, pulsation of the medium in the pipeline, etc.). Under such vibration conditions, the nuts in the existing technology are very prone to backing back due to continuous vibration load. The backing back of the nuts will cause the seal between the pipeline and the safety valve to fail, which may lead to medium leakage, waste of resources and environmental pollution.

[0004] Therefore, how to prevent the nut connecting the valve body and the pipeline from retracting under vibration is a technical problem that urgently needs to be solved in this field.

[0005] It should be noted that the information disclosed in this background section is only for understanding the background technology of the present application concept, and therefore, the above description is not considered to constitute prior art information. Utility Model Content

[0006] This disclosure provides at least one maintenance-free pilot-operated safety valve to solve the technical problem of the nut retraction between the valve body and the pipeline under vibration.

[0007] In a first aspect, embodiments of this disclosure provide a maintenance-free pilot-operated safety valve, comprising: a main valve, a pilot valve, a connecting structure connecting the main valve and the pilot valve, and a connector; the connecting structure comprises: a plurality of pipe fittings; a locking member fitted onto both ends of the pipe fittings, the locking member comprising a nut and an extension sleeve, the extension sleeve having a first thread on its outer side, the first thread being a reverse thread; and an anti-retraction member connected to the extension sleeve, the anti-retraction member comprising a backstop sleeve, the backstop sleeve having a second thread on its inner side adapted to the first thread on the outer side of the extension sleeve, the second thread being a reverse thread opposite in direction to the first thread; wherein the backstop sleeve and the extension sleeve are screwed together by the reverse thread to restrict the nut from retracting.

[0008] In one optional embodiment, a first rubber ring is sleeved on the outer side of the extension tube; the anti-reverse component further includes a stop ring, the inner diameter of which is smaller than the maximum outer diameter of the nut, and a second rubber ring on the inner side of the stop ring; wherein, when the end face of the anti-reverse tube abuts against the first rubber ring, the second rubber ring abuts against the end face of the extension tube.

[0009] In one alternative embodiment, both the first rubber ring and the second rubber ring are hollow.

[0010] In one alternative embodiment, the wall thickness of the second rubber ring in the direction of the central axis of the stop ring is less than the wall thickness of the rest, and it deforms and bulges towards the center when squeezed.

[0011] In one optional embodiment, the pipe fitting is a metal bend or a metal straight pipe, with both ends connected to the connectors on the main valve and the pilot valve respectively via locking components.

[0012] Secondly, this disclosure also provides a maintenance-free pilot-operated safety valve, comprising: a plurality of pipe fittings, which are metal bends or metal straight pipes; a locking member, which is sleeved on both ends of the pipe fittings, wherein the pipe fittings are connected to the connectors on the main valve and the pilot valve through the locking member; the locking member includes a nut and an extension sleeve, wherein the extension sleeve has a first thread on its outer side, and the first thread is a reverse thread; an anti-retraction member, which is connected to the extension sleeve, wherein the anti-retraction member includes a backstop sleeve, wherein the backstop sleeve has a second thread on its inner side that is adapted to the first thread on the outer side of the extension sleeve, and the second thread is a reverse thread with the opposite direction of rotation to the first thread; wherein the backstop sleeve and the extension sleeve are screwed together by the reverse thread to restrict the nut from retracting.

[0013] In one alternative embodiment, a first rubber ring is fitted around the outer side of the extension tube.

[0014] In one optional embodiment, the anti-reverse component further includes a stop ring, the inner diameter of which is smaller than the maximum outer diameter of the nut, and a second rubber ring on the inner side of the stop ring; wherein, when the end face of the anti-reverse cylinder abuts against the first rubber ring, the second rubber ring abuts against the end face of the extension cylinder.

[0015] In one alternative embodiment, the second rubber ring is hollow.

[0016] In one alternative embodiment, the wall thickness of the second rubber ring in the direction of the central axis of the stop ring is less than the wall thickness of the rest, and it deforms and bulges towards the center when squeezed.

[0017] The beneficial effect of this utility model is that it provides a maintenance-free pilot-operated safety valve; By setting the reverse first thread on the outside of the extension tube and the reverse second thread on the inside of the anti-reverse tube, the reverse thread engagement connection of the two is realized, which solves the industry pain point that traditional single-threaded nuts are prone to retraction due to vibration load, and ensures the long-term tightness of the connection structure. By setting a hollow first rubber ring, the gap between the anti-reverse cylinder and the extension cylinder is fully filled when the anti-reverse cylinder end face is squeezed; at the same time, it absorbs vibration energy, reduces the impact damage of vibration to the threaded connection, improves the service life of the locking part and the anti-reverse part, and reduces the frequency of maintenance. By setting a hollow second rubber ring with a thinner wall thickness facing the central axis of the stop ring, it deforms and bulges towards the center when it comes into contact with and is squeezed against the end face of the extension cylinder. On the one hand, it fills the gap between the end face of the extension cylinder and the stop ring; on the other hand, the reaction force generated by the bulging deformation forms an auxiliary locking effect on the extension cylinder, further enhancing the anti-reverse effect.

[0018] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objectives and other advantages of this invention are realized and obtained through the structures particularly pointed out in the description and the accompanying drawings.

[0019] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 A perspective view of a maintenance-free pilot-operated safety valve provided in an embodiment of this disclosure; Figure 2 A perspective view of the locking member and the anti-reverse member in a separated state provided in an embodiment of this disclosure; Figure 3 This is a cross-sectional view of the locking member and the anti-reverse member in a separated state, as provided in an embodiment of this disclosure.

[0022] In the picture: 1. Main valve; 2. Pilot valve; 3. Connecting structure; 31. Pipe fitting; 32. Locking component; 321. Nut; 322. Extension sleeve; 323. First rubber ring; 33. Anti-reverse component; 331. Anti-reverse sleeve; 332. Stop ring; 333. Second rubber ring; 4. Connector. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0024] In this document, when it is mentioned that a first component is located on a second component, this can mean that the first component can be directly formed on the second component, or that a third component can be inserted between the first and second components. Furthermore, in the accompanying drawings, the thickness of the components may be exaggerated or reduced for the purpose of effectively describing the technical content.

[0025] In this document, exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. As used herein, expressions such as “at least one of…” modify the entire list of elements when following a list of elements, rather than individual elements in the list. For example, the expression “at least one of a, b, and c” should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0026] The terminology used herein is for the purpose of describing specific exemplary configurations only and is not intended to be limiting. As used herein, the singular articles “a,” “an,” and “the” may also be intended to include plural forms unless otherwise clearly stated herein. The terms “comprising,” “including,” and “having” are inclusive and thus specify the presence of features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein should not be construed as requiring them to be performed in the specific order discussed or shown, unless specifically identified as such. Additional or alternative steps may be employed.

[0027] As used herein, the phrases “in one embodiment,” “according to one embodiment,” “in some embodiments,” etc., generally refer to the fact that a particular feature, structure, or characteristic following the phrase can be included in at least one embodiment of this disclosure. Therefore, a particular feature, structure, or characteristic can be included in more than one embodiment of this disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms “example,” “exemplary,” etc., are used to “serve as an example, instance, or illustration.” Any implementation, aspect, or design described herein as “example” or “exemplary” is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. Rather, the use of the terms “example,” “exemplary,” etc., is intended to present concepts in a specific manner.

[0028] Research has revealed the following drawbacks of existing technologies: In related technologies, the main valve and pilot valve of a pilot-operated safety valve are connected by a pipeline, and the nuts used for fastening at the connection point often employ a traditional single-threaded structure. However, the industrial environment in which safety valves operate is often accompanied by high-frequency vibrations (such as pump operation and pulsation of the medium in the pipeline). Under such vibration conditions, the nuts in existing technologies are prone to retraction due to continuous vibration loads. Nut retraction can lead to seal failure between the pipeline and the safety valve, potentially causing media leakage, resource waste, and environmental pollution.

[0029] Therefore, how to prevent the nut connecting the valve body and the pipeline from retracting under vibration is a technical problem that urgently needs to be solved in this field.

[0030] The shortcomings of the above solutions are the result of the utility model inventor's practice and careful research. Therefore, the discovery process of the above problems and the solutions proposed in this disclosure should be considered as contributions made by the utility model inventor to this disclosure.

[0031] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0032] The following detailed description, with reference to the accompanying drawings, describes some embodiments of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0033] like Figures 1 to 3 As shown, some embodiments provide a maintenance-free pilot-operated safety valve, including: a main valve 1, a pilot valve 2, a connection structure 3 connecting the main valve 1 and the pilot valve 2, and a connector 4; similar to related technologies, the main valve 1 is the core actuator of the pilot-operated safety valve, and its main function is to quickly open to discharge the medium when the system pressure exceeds the set pressure, thereby controlling the system pressure within a safe range; the pilot valve 2 is a pressure sensing and control component, which senses the medium pressure in the system in real time and converts the pressure signal into a control action, thereby driving the main valve 1 to open and close.

[0034] In the working system of a pilot-operated safety valve, the main valve 1 and the pilot valve 2 do not work independently, but rather form a close coordinated control relationship: when the system pressure is within the normal range, the pilot valve 2 remains closed, and the main valve 1 is also closed under the balance of the medium pressure and its own spring force, ensuring that the medium does not leak; when the system pressure rises and exceeds the set pressure, the valve core of the pilot valve 2 opens under pressure, and the medium in the upper chamber of the main valve 1 is discharged through the pilot valve 2, resulting in a pressure difference between the upper and lower chambers of the main valve 1. Driven by the pressure difference, the valve core of the main valve 1 opens, and a large amount of medium is discharged to reduce the system pressure; when the system pressure drops below the set pressure, the valve core of the pilot valve 2 resets and closes, the pressure in the upper chamber of the main valve 1 gradually recovers, and the main valve 1 closes under the action of the spring force, restoring the sealing state. The connector 4 is a transition component connecting the main valve 1, the pilot valve 2 and the pipe fitting 31. Its structural design needs to be compatible with the outlet end of the main valve 1, the inlet end of the pilot valve 2 and the end structure of the pipe fitting 31. It usually adopts a threaded connection or a flange connection (in this embodiment, in conjunction with the use of the locking part 32, the threaded adaptation structure is preferred).

[0035] The core function of connector 4 is to enable detachable connection between main valve 1, pilot valve 2 and pipe fitting 31, while ensuring the sealing performance of the connection to prevent leakage of the medium during transmission.

[0036] The connection structure 3 includes several pipe fittings 31. The connection structure 3 is the core component for realizing the medium transmission between the main valve 1 and the pilot valve 2. It is also the key to solving the problem of the nut retraction in traditional safety valves. It includes several pipe fittings 31, locking parts 32 and anti-retraction parts 33. The components cooperate with each other to form a complete "transmission-fastening-anti-retraction" system. Fitting 31 is the channel for media transmission. Its number is determined according to the installation distance between the main valve 1 and the pilot valve 2 and the installation space layout. It is usually 1-3 (for example, when the main valve 1 and the pilot valve 2 are close and the installation space is open, one straight pipe is used; when there is a positional deviation between the two or the installation space is narrow, one bend or a combination of multiple straight pipes and bends is used).

[0037] Fitting 31 is made of metal (such as carbon steel or stainless steel), specifically a metal bend or a metal straight pipe. The choice depends on the pressure level, medium characteristics, and installation environment of the actual application scenario. For example, under high pressure conditions, thicker stainless steel straight pipes are preferred to ensure sufficient pressure resistance. In scenarios where the medium is corrosive, corrosion-resistant stainless steel is used to prevent fitting 31 from being damaged by corrosion. When installation space is limited and the direction of medium transmission needs to be changed, metal bends (such as 90° bends or 45° bends) are selected to adapt to the space layout requirements. Both ends of the pipe fitting 31 are provided with structures (such as external threads) that are compatible with the connector 4 and the locking element 32, so as to facilitate communication with the connector 4 and to be fastened by the locking element 32 to ensure the stability of the connection. The pipe fitting 31 is combinable (multiple straight pipes and bends can be combined), which improves the installation flexibility of the safety valve and can adapt to the installation position requirements of the main valve 1 and pilot valve 2 in different industrial scenarios. It does not require large-scale modification of the installation site and reduces installation costs. In addition, the inner wall of the pipe fitting 31 is smooth and has good sealing performance, which can ensure the sealing and smoothness of media transmission, avoid resource waste and environmental pollution caused by media leakage, and at the same time ensure that the pilot valve 2 can obtain the system pressure signal in real time and accurately, so as to provide a guarantee for the precise operation of the main valve 1. The locking component 32 is fitted onto both ends of the pipe fitting 31. The locking component 32 includes a nut 321 and an extension sleeve 322. The extension sleeve 322 has a first thread on its outer side, and the first thread is a reverse thread. The locking component 32 is fitted onto both ends of the pipe fitting 31 and is the core component for achieving a tight connection between the pipe fitting 31 and the connector 4. It includes a nut 321, an extension sleeve 322 and a first rubber ring 323. The components work together to ensure the tightness of the connection and enhance the sealing performance.

[0038] The anti-reverse component 33 is connected to the extension tube 322. The anti-reverse component 33 includes a backstop tube 331. The inner side of the backstop tube 331 is provided with a second thread that is adapted to the first thread on the outer side of the extension tube 322. The second thread is a reverse thread with the opposite direction of the first thread. The anti-reverse component 33 is connected to the extension tube 322 and is a key component to enhance the anti-reverse effect of the locking component 32. It includes a backstop tube 331, a stop ring 332, and a second rubber ring 333. The components cooperate with each other to form a multi-layer anti-reverse and sealing system with the locking component 32, which consists of "reverse thread interlocking + mechanical limit + rubber sealing".

[0039] The anti-reverse sleeve 331 and the extension sleeve 322 are connected by reverse thread to restrict the retraction of the nut 321.

[0040] Nut 321 is the operating component of locking part 32. It has an internal thread on its inner side, which is compatible with the external thread on the outer side of connector 4. The pipe 31 and connector 4 are fastened together by screwing. Nut 321 is usually hexagonal (or dodecagonal) in shape, which makes it easy to operate with tools such as wrenches and improves installation efficiency.

[0041] It should be further explained that the thread profile of nut 321 (such as triangular thread) has been optimized and has good self-locking performance. In the absence of external vibration, it can prevent loosening by the friction between the threads. At the same time, the wall thickness of nut 321 is determined according to the pressure level of the actual working conditions to ensure that it will not deform or break due to excessive force during the tightening process. The fixed connection between nut 321 and extension sleeve 322 (such as welding or integral molding) forms an integral structure, which avoids relative loosening between nut 321 and extension sleeve 322 and lays the foundation for subsequent cooperation with anti-retraction component 33. In addition, nut 321 is made of high-strength alloy material, which has good wear resistance and corrosion resistance. During long-term use, the connection will not loosen due to thread wear, nor will the service life be affected by media corrosion, ensuring the long-term stability of the connection.

[0042] The extension sleeve 322 is a key component connecting the nut 321 and the anti-reverse component 33. One end of it is fixedly connected to the nut 321 (e.g., by welding or integral molding), and the other end has a first thread (reverse thread) on the outside, which is adapted to the second thread (reverse thread) on the inside of the anti-reverse component 33 and the anti-reverse sleeve 331.

[0043] The length of the extension sleeve 322 is determined according to the structural dimensions of the anti-reverse component 33, and is usually 1.5-2 times the height of the nut 321, to ensure sufficient engagement length between it and the anti-reverse sleeve 331 and to ensure the stability of the connection. The first thread on the outer side of the extension sleeve 322 adopts a reverse thread design (that is, the direction of rotation is opposite to that of the inner fastening thread of the nut 321; for example, if the inner thread of the nut 321 is a right-hand thread, then the first thread is a left-hand thread). The main purpose is that, under high-frequency vibration environment, the friction between the threads of a traditional single-threaded nut will decrease due to vibration load, and then rotate in the loosening direction (opposite to the tightening direction), eventually causing it to retract. When the reverse thread of the extension sleeve 322 is engaged with the reverse thread of the anti-retraction sleeve 331, when the nut 321 has a tendency to retract (that is, rotate in the loosening direction), it will drive the extension sleeve 322 to rotate synchronously. At this time, the reverse threads between the extension sleeve 322 and the anti-retraction sleeve 331 will generate a mutual locking force, preventing the extension sleeve 322 from continuing to rotate, thereby limiting the retraction of the nut 321.

[0044] The reverse thread design fundamentally solves the problem of nut 321 retraction under vibration environment. Through the interlocking of the reverse threads of extension sleeve 322 and anti-retraction sleeve 331, a "retraction prevention barrier" is formed. Even under high-frequency vibration conditions (such as 200-500Hz vibration generated by pump operation and 100-300Hz vibration generated by pipeline medium pulsation), it can effectively prevent nut 321 from retraction and avoid sealing failure at the connection.

[0045] In addition, the extension tube 322 extends the overall length of the locking member 32, providing sufficient installation space for the anti-reverse member 33, allowing the anti-reverse member 33 to fit tightly with the locking member 32. It also facilitates the inspection of the installation status of the connection (such as by observing the engagement position of the extension tube 322 and the anti-reverse tube 331 to determine whether there is any looseness). Furthermore, the fixed connection between the extension tube 322 and the nut 321 ensures synchronous movement between the two, avoiding anti-reverse failure caused by relative looseness between the two, and further improving the reliability of the connection.

[0046] The anti-reverse sleeve 331 is the core component of the anti-reverse part 33. It has a second thread (reverse thread) on its inner side, which is adapted to the first thread (reverse thread) on the outer side of the extension sleeve 322 and is connected to the extension sleeve 322 by screwing.

[0047] The anti-lock sleeve 331 is made of the same material as the extension sleeve 322 (such as a high-strength alloy) to ensure that both have the same coefficient of thermal expansion, preventing thread loosening due to differences in the coefficient of thermal expansion during temperature changes. The length of the anti-lock sleeve 331 is matched with the length of the extension sleeve 322, typically 0.6-0.8 times the length of the extension sleeve 322, to ensure sufficient engagement length between the two and ensure connection stability. The core anti-retraction mechanism is the reverse thread engagement of the anti-retraction sleeve 331 and the extension sleeve 322: When the nut 321 is subjected to vibration load and tends to retract (i.e., rotates in the loosening direction), it will drive the extension sleeve 322 to rotate synchronously. Since the first thread of the extension sleeve 322 and the second thread of the anti-retraction sleeve 331 are reverse threads, the rotation direction of the extension sleeve 322 is exactly the tightening direction of the anti-retraction sleeve 331. At this time, the anti-retraction sleeve 331 will further engage with the extension sleeve 322, generating a mutually locking force that prevents the extension sleeve 322 from continuing to rotate, thereby limiting the retraction of the nut 321. At the same time, one end of the anti-retraction sleeve 331 is fixedly connected to the stop ring 332 (such as by welding or integral molding), forming an integral structure to ensure that there is no relative loosening between the anti-retraction sleeve 331 and the stop ring 332, further strengthening the anti-retraction effect. It should be further explained that, firstly, the reverse thread interlocking of the anti-reverse sleeve 331 and the extension sleeve 322 structurally eliminates the possibility of the nut 321 retracting, solving the technical problem of easy retraction of traditional single-threaded nuts, and maintaining the tightness of the connection even under long-term high-frequency vibration conditions; secondly, the consistency of materials between the anti-reverse sleeve 331 and the extension sleeve 322 avoids thread loosening caused by temperature changes, ensuring good anti-retraction performance in scenarios with large temperature fluctuations (such as pressure control of reactors in the petrochemical industry and pressure control of steam pipelines in the energy and power industry); in addition, the anti-reverse sleeve 331 has a simple structural design, is easy to process and install, requires no complex auxiliary equipment, and reduces production costs and installation difficulty. The stop ring 332 is fixedly connected to the anti-reverse sleeve 331 (e.g., by welding or integral molding). Its inner diameter is smaller than the maximum outer diameter of the nut 321. It is usually a ring structure and its material is the same as that of the anti-reverse sleeve 331 (e.g., high-strength alloy).

[0048] The main function of the stop ring 332 is to achieve mechanical limiting: during the installation process, when the nut 321 is screwed to the designated position (i.e., the pipe fitting 31 and the connector 4 are tightly connected), the stop ring 332 will abut against the end face of the nut 321. At this time, the nut 321 cannot be screwed on further, thus avoiding damage to the pipe fitting 31 or the connector 4 due to the nut 321 being screwed on too tightly.

[0049] An extension cylinder 322 is fitted with a first rubber ring 323 on its outer side; the anti-reverse component 33 also includes a stop ring 332, the inner diameter of which is smaller than the maximum outer diameter of the nut 321, and a second rubber ring 333 on the inner side of the stop ring 332. When the end face of the anti-reverse cylinder 331 abuts against the first rubber ring 323, the second rubber ring 333 abuts against the end face of the extension cylinder 322; the extension cylinder 322 is also fitted with a first rubber ring 323 on its outer side, which is interference-fitted with the extension cylinder 322 to ensure that the first rubber ring 323 will not fall off the extension cylinder 322 during vibration.

[0050] The first rubber ring 323 is sleeved on the outside of the extension cylinder 322 and is interference-fitted with the extension cylinder 322. Its material is an oil-resistant, temperature-resistant, and corrosion-resistant rubber material (such as nitrile rubber or fluororubber). The specific material selection depends on the type of medium and temperature range in the application scenario of the safety valve. For example, in the petrochemical industry, where the medium is mostly oily substances such as crude oil and gasoline, nitrile rubber is the preferred material for the first rubber ring 323. The first rubber ring 323 has a circular or rectangular cross-sectional shape, and its inner diameter is slightly smaller than the outer diameter of the extension tube 322. It is tightly fitted onto the extension tube 322 by interference fit to ensure that it will not fall off due to vibration. The first rubber ring 323 mainly serves two functions: First, it acts as a seal. When the anti-reverse sleeve 331 and the extension sleeve 322 are screwed together to a certain position, the end face of the anti-reverse sleeve 331 will abut against the first rubber ring 323. At this time, the first rubber ring 323 undergoes elastic deformation under the squeezing action of the anti-reverse sleeve 331, filling the gap between the end face of the anti-reverse sleeve 331 and the extension sleeve 322, forming a sealing surface to prevent the medium from leaking from the connection between the extension sleeve 322 and the anti-reverse sleeve 331. Second, it acts as a buffer. Under high-frequency vibration, the elastic deformation of the first rubber ring 323 can absorb some vibration energy, reducing the vibration impact between the extension sleeve 322 and the anti-reverse sleeve 331, avoiding thread wear caused by long-term vibration friction, and extending service life.

[0051] Specifically, the sealing effect of the first rubber ring 323 and the sealing structure of the connector 4 form a double seal, which further improves the sealing performance of the connection and solves the problem of medium leakage caused by the failure of a single sealing structure in traditional connection methods, reducing resource waste and environmental pollution. Secondly, the buffering effect can reduce the damage of vibration to the threads of the extension cylinder 322 and the anti-reverse cylinder 331, avoid the failure of anti-reverse due to thread wear, and extend the service life of the locking part 32 and the anti-reverse part 33. In addition, the oil resistance, temperature resistance and corrosion resistance of the first rubber ring 323 enable it to adapt to the use requirements of different industrial scenarios, ensuring that it can maintain good sealing and buffering performance under harsh working conditions, and improving the applicability and reliability of the safety valve.

[0052] The second rubber ring 333 is located inside the stop ring 332 and is a hollow structure. At the same time, the wall thickness of the second rubber ring 333 facing the central axis of the stop ring 332 is less than the wall thickness of the rest. When squeezed, it bulges and deforms towards the center.

[0053] Both the first rubber ring 323 and the second rubber ring 333 are hollow. When the end face of the anti-reverse cylinder 331 abuts against the first rubber ring 323, the second rubber ring 333 abuts against the end face of the extension cylinder 322. Under the action of extrusion pressure, due to its specific wall thickness distribution, it will bulge and deform towards the center. On the one hand, it fills the gap between the end face of the extension cylinder 322 and the stop ring 332, further enhancing the sealing effect and forming a double seal with the first rubber ring 323. On the other hand, the reaction force generated by the bulging deformation can generate a certain locking force on the extension cylinder 322, helping to prevent the extension cylinder 322 from driving the nut 321 to retract.

[0054] Its hollow structure and special wall thickness distribution give it unique deformation characteristics, allowing it to bulge precisely towards the center during extrusion, resulting in a better sealing effect. The dual sealing mechanism can minimize the risk of media leakage. At the same time, the auxiliary locking effect further enhances the anti-reverse effect, enabling the entire connection structure to remain stable in high-frequency vibration environments and meet the requirements of maintenance-free operation.

[0055] The wall thickness of the second rubber ring 333 facing the central axis of the stop ring 332 is less than the wall thickness of the rest, and it bulges and deforms towards the center when squeezed.

[0056] The fitting 31 is a metal bend or a metal straight pipe, and its two ends are connected to the connectors 4 on the main valve 1 and the pilot valve 2 respectively through locking parts 32.

[0057] Some embodiments provide a maintenance-free pilot-operated safety valve, comprising: a plurality of pipe fittings 31, which are metal bends or metal straight pipes; a locking member 32, which is fitted over both ends of the pipe fittings 31, the pipe fittings 31 being connected to the connectors 4 on the main valve 1 and the pilot valve 2 via the locking member 32; the locking member 32 includes a nut 321 and an extension sleeve 322, the extension sleeve 322 having a first thread on its outer side, and the first thread being a reverse thread; an anti-retraction member 33, which is connected to the extension sleeve 322, the anti-retraction member 33 including a backstop sleeve 331, the backstop sleeve 331 having a second thread on its inner side that is adapted to the first thread on the outer side of the extension sleeve 322, and the second thread being a reverse thread with the opposite direction of rotation to the first thread; wherein, the backstop sleeve 331 and the extension sleeve 322 are screwed together via the reverse thread to restrict the nut 321 from retracting.

[0058] The extension tube 322 is fitted with a first rubber ring 323 on its outer side.

[0059] The anti-reverse component 33 also includes a stop ring 332, the inner diameter of which is smaller than the maximum outer diameter of the nut 321. The stop ring 332 has a second rubber ring 333 on its inner side. When the end face of the anti-reverse cylinder 331 abuts against the first rubber ring 323, the second rubber ring 333 abuts against the end face of the extension cylinder 322. The second rubber ring 333 is hollow. The wall thickness of the second rubber ring 333 towards the central axis of the stop ring 332 is smaller than the wall thickness of the rest. When squeezed, it bulges and deforms towards the center.

[0060] Overall workflow: (a) Installation phase Component assembly: First, the first rubber ring 323 is fitted onto the outside of the extension tube 322 to ensure that the first rubber ring 323 fits tightly with the extension tube 322; then the nut 321 is fixedly connected to the extension tube 322 to form a complete locking component 32; next, the second rubber ring 333 is installed on the inside of the stop ring 332, and then the stop ring 332 is fixedly connected to the anti-reverse tube 331 to form an anti-reverse component 33.

[0061] Connecting the main valve and the pilot valve: Based on the installation position and spatial layout of the main valve 1 and the pilot valve 2, select an appropriate number and type (bend or straight pipe) of fittings 31. Connect one end of the fitting 31 to the main valve 1 through the connector 4. Specifically, put the locking part 32 on the end of the fitting 31 and screw the nut 321 into the external thread of the connector 4 for initial tightening. Then, screw the anti-reverse sleeve 331 and the extension sleeve 322 in the anti-reverse part 33 into the reverse thread until the end face of the anti-reverse sleeve 331 abuts against the first rubber ring 323. At this time, the second rubber ring 333 abuts against the end face of the extension sleeve 322, completing the connection of one end of the fitting 31 to the main valve 1. In the same way, connect the other end of the fitting 31 to the pilot valve 2 through the connector 4 to complete the installation of the entire safety valve.

[0062] (II) Normal working phase Pressure monitoring and main valve closure: When the system is running normally, the medium pressure is below the set pressure. After sensing the system pressure, the pilot valve 2 remains closed. The medium pressure in the upper chamber of the main valve 1 is balanced with the system pressure. Under the action of the spring force, the valve core of the main valve 1 is closed, and the medium cannot be discharged through the main valve 1. The entire system remains sealed. At this time, the pipe fitting 31 in the connecting structure 3 normally transmits the medium pressure signal to the pilot valve 2. The locking part 32 and the anti-retraction part 33 are kept tight by reverse thread engagement and mechanical limit (stop ring 332). The first rubber ring 323 and the second rubber ring 333 are in a slightly compressed state to ensure the sealing of the connection and prevent medium leakage.

[0063] Pressure Exceedance and Main Valve Opening: When the system pressure exceeds the set pressure, the pilot valve 2 senses the pressure change and opens. The medium in the upper chamber of the main valve 1 is discharged through the pilot valve 2, causing the pressure in the upper chamber of the main valve 1 to decrease. A pressure difference is formed on both sides of the valve core of the main valve 1. Driven by the pressure difference, the valve core opens, and a large amount of medium is discharged through the main valve 1, and the system pressure gradually decreases. During this process, the connecting structure 3 needs to withstand the pressure and vibration brought by the medium flow. Due to the interlocking effect of the reverse threads of the locking part 32 and the anti-retraction part 33, even if it is affected by vibration, the nut 321 will not retract. At the same time, the elastic deformation of the first rubber ring 323 and the second rubber ring 333 is further optimized under the action of pressure and vibration, which can better fill the gap, maintain the seal, and prevent the medium from leaking from the connection part.

[0064] Pressure recovery and main valve closure: When the system pressure drops below the set pressure, pilot valve 2 closes, and the medium pressure in the upper chamber of main valve 1 gradually recovers. Under the action of the spring force, the valve core of main valve 1 closes, and the system returns to normal sealing. All components in connection structure 3 remain stable. The locking force of the reverse thread, the limiting effect of the stop ring 332, and the sealing and buffering effect of the rubber ring remain effective, ensuring that the entire safety valve can respond to the next pressure exceedance at any time.

[0065] During normal operation, the precise pressure sensing of pilot valve 2 and the timely action of main valve 1 ensure effective control of system pressure and prevent safety accidents caused by excessive pressure. The anti-retraction and sealing mechanism of connection structure 3 is stable and reliable. Under high-frequency vibration and pressure change conditions, nut 321 does not retract and there is no medium leakage at the connection point, achieving the requirement of maintenance-free operation, reducing resource waste and environmental pollution. At the same time, the stable operation of each component also extends the service life of the safety valve and reduces equipment operating costs.

[0066] In summary, this utility model: By setting the reverse first thread on the outside of the extension sleeve 322 and the reverse second thread on the inside of the anti-reverse sleeve 331, the reverse thread engagement connection of the two is realized, which prevents the nut 321 from retreating under high-frequency vibration environment from the structural source. This solves the industry pain point that traditional single-threaded nuts are prone to retreating due to vibration load, and ensures the long-term fastening of the connection structure 3.

[0067] By setting a hollow first rubber ring 323, its excellent elastic deformation ability is utilized to fully fill the gap between the anti-reverse cylinder 331 and the extension cylinder 322 when the anti-reverse cylinder 331 is squeezed at the end face, thus achieving a first-level seal at the connection. At the same time, it absorbs vibration energy, reduces the impact damage of vibration on the threaded connection, improves the service life of the locking part 32 and the anti-reverse part 33, and reduces the frequency of maintenance.

[0068] By setting a hollow second rubber ring 333 with a thinner wall thickness towards the central axis of the stop ring 332, it deforms and bulges towards the center when it comes into contact with and is squeezed against the end face of the extension cylinder 322. On the one hand, it fills the gap between the end face of the extension cylinder 322 and the stop ring 332, forming a double seal with the first rubber ring 323, which significantly improves the sealing performance of the connection and reduces the risk of media leakage. On the other hand, the reaction force generated by the bulging deformation forms an auxiliary locking on the extension cylinder 322, further enhancing the anti-retraction effect.

[0069] By setting a stop ring 332 with an inner diameter smaller than the maximum outer diameter of the nut 321, mechanical limitation on the axial displacement of the nut 321 is achieved. This complements the anti-retraction mechanism of the reverse thread, preventing the nut 321 from moving excessively axially due to vibration, improving the reliability of the anti-retraction structure, and ensuring the stability of the connection.

[0070] In the description of the embodiments of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0071] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence unless expressly indicated herein. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer, or segment discussed above may be referred to as the second element, component, region, layer, or segment.

[0072] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A maintenance-free pilot-operated safety valve, characterized in that, include: Main valve (1), pilot valve (2), connection structure (3) connecting the main valve (1) and pilot valve (2) and connector (4); The connection structure (3) includes: Several pipe fittings (31); A locking element (32) is fitted onto both ends of a pipe fitting (31). The locking element (32) includes a nut (321) and an extension tube (322). The extension tube (322) has a first thread on its outer side, and the first thread is a reverse thread. Anti-retraction component (33), which is connected to extension tube (322), the anti-retraction component (33) includes anti-retraction tube (331), the inner side of the anti-retraction tube (331) is provided with a second thread that is adapted to the first thread on the outer side of the extension tube (322), and the second thread is a reverse thread with the opposite direction of the first thread; The anti-reverse sleeve (331) and the extension sleeve (322) are connected by reverse thread to restrict the retraction of the nut (321).

2. The maintenance-free pilot-operated safety valve as described in claim 1, characterized in that, The extension tube (322) is fitted with a first rubber ring (323) on its outer side; The anti-retraction component (33) also includes a stop ring (332), the inner diameter of which is smaller than the maximum outer diameter of the nut (321), and a second rubber ring (333) on the inner side of the stop ring (332). When the end face of the anti-reverse sleeve (331) abuts against the first rubber ring (323), the second rubber ring (333) abuts against the end face of the extension sleeve (322).

3. The maintenance-free pilot-operated safety valve as described in claim 2, characterized in that, Both the first rubber ring (323) and the second rubber ring (333) are hollow.

4. The maintenance-free pilot-operated safety valve as described in claim 3, characterized in that, The wall thickness of the second rubber ring (333) in the direction of the central axis of the stop ring (332) is less than the wall thickness of the rest, and it bulges and deforms towards the center when squeezed.

5. The maintenance-free pilot-operated safety valve as described in claim 1, characterized in that, The pipe fitting (31) is a metal bend or a metal straight pipe, and its two ends are connected to the connectors (4) on the main valve (1) and the pilot valve (2) respectively through locking parts (32).

6. A maintenance-free pilot-operated safety valve, characterized in that, include: Several pipe fittings (31), which are metal bends or metal straight pipes; Locking element (32) is fitted onto both ends of pipe fitting (31), which is connected to the connector (4) on the main valve (1) and pilot valve (2) through locking element (32); The locking component (32) includes a nut (321) and an extension tube (322). The extension tube (322) has a first thread on its outer side, and the first thread is a reverse thread. Anti-retraction component (33), which is connected to extension tube (322), the anti-retraction component (33) includes anti-retraction tube (331), the inner side of the anti-retraction tube (331) is provided with a second thread that is adapted to the first thread on the outer side of the extension tube (322), and the second thread is a reverse thread with the opposite direction of the first thread; The anti-reverse sleeve (331) and the extension sleeve (322) are connected by reverse thread to restrict the retraction of the nut (321).

7. The maintenance-free pilot-operated safety valve as described in claim 6, characterized in that, The extension tube (322) is fitted with a first rubber ring (323) on its outer side.

8. The maintenance-free pilot-operated safety valve as described in claim 7, characterized in that, The anti-retraction component (33) also includes a stop ring (332), the inner diameter of which is smaller than the maximum outer diameter of the nut (321), and a second rubber ring (333) on the inner side of the stop ring (332). When the end face of the anti-reverse sleeve (331) abuts against the first rubber ring (323), the second rubber ring (333) abuts against the end face of the extension sleeve (322).

9. The maintenance-free pilot-operated safety valve as described in claim 8, characterized in that, The second rubber ring (333) is hollow.

10. The maintenance-free pilot-operated safety valve as described in claim 9, characterized in that, The wall thickness of the second rubber ring (333) in the direction of the central axis of the stop ring (332) is less than the wall thickness of the rest, and it bulges and deforms towards the center when squeezed.

Images