A manual and pneumatic emergency cut-off valve

Abstract

The present invention relates to the technical field of cut-off valves, and particularly to a manual pneumatic emergency cut-off valve, which includes a valve body, a manual device, a pneumatic device, a valve stem, and a valve flap. The pneumatic device and the manual device are arranged on the valve body. The pneumatic device is connected to an external air supply device. The air supply device controls the opening and closing state of the cut-off valve by charging and discharging air into the pneumatic device. The manual device controls the opening and closing state of the emergency cut-off valve by manual operation. By setting a protective cover, during the opening and closing process of the cut-off valve, the protective cover can be used to replace the valve flap to be subjected to cavitation, thereby avoiding the wear of the valve flap caused by cavitation. At the same time, when the cut-off valve is already closed, the compensation unit is used to prevent the protective cover from being damaged due to extrusion pressure, so as to solve the problems raised in the above background technology. Ultimately, the valve flap of the manual pneumatic emergency cut-off valve can be effectively protected, thereby ensuring the reliability of the cut-off valve during the working process.

Description

Technical Field

[0001] The present invention relates to the technical field of cut-off valves, and specifically to a manual and pneumatic emergency cut-off valve. Background Art

[0002] An emergency cut-off valve, also known as a safety cut-off valve, is a valve used to avoid accidents by quickly cutting off or connecting a fluid pipeline in case of an emergency.

[0003] In the existing cut-off valves, when used in a high-pressure liquid pipeline, during the process of the valve opening from the closed state, there is a huge pressure difference on both sides of the gate inside the cut-off valve. At this time, the liquid may undergo flash evaporation, resulting in wear and damage to the valve flap of the cut-off valve, that is, the cut-off valve is cavitated. The cavitation phenomenon causes greater wear on the valve flap when the opening of the cut-off valve is smaller. After the valve flap is cavitated, it will affect the sealing effect of the valve flap on the gate, ultimately leading to leakage of the cut-off valve.

[0004] Among the existing cut-off valves, there is a type of manual and pneumatic emergency cut-off valve. Its main usage method is that the control system controls the charging and discharging of the air supply system to achieve the opening and closing of the cut-off valve; only when the pneumatic device fails or in special cases (for example, when on-site workers have already discovered possible safety hazards, and the control system still has not controlled the cut-off valve to start the emergency action), the operator needs to use the manual device to manually operate the cut-off valve. This means that the manual device of this type of cut-off valve has a low usage frequency.

[0005] Therefore, when the parts inside the manual device rust, the rust will continue to accumulate. After the manual device has been idle for a long time and is used again, these rusts will hinder the operator from operating the cut-off valve, increasing the difficulty of opening or closing the cut-off valve, thus increasing the opening and closing time of the cut-off valve. This may force the cut-off valve to be in a small opening state for a longer time, further causing additional wear on the valve flap.

[0006] For the above problems, a conventional solution is to shorten the time for manually opening and closing the cut-off valve, thereby shortening the time when the cut-off valve is in a small opening state. However, particularly for existing plunger cut-off valve products, in order to achieve good mechanical reliability while taking into account economy, a threaded rod is usually used as a measure to control the opening and closing state of the valve flap. Specifically, when the worker screws the threaded rod into the thread on the valve body that mates with it, the valve flap closes and the cut-off valve cuts off the pipeline. Conversely, when the worker unscrews the threaded rod, the valve flap opens and the pipeline resumes connection. For this opening and closing method, considering the need to avoid misoperation of the equipment and the reliability of the equipment, the force for rotating the threaded rod must be designed with a certain threshold during design, making it relatively difficult to rotate the threaded rod. Thus, for plunger cut-off valves, there is a certain contradiction between the idea of reducing cavitation by reducing the opening and closing difficulty and the actual design of the cut-off valve.

[0007] In addition, there is another conventional solution, which is to set a protective layer outside the valve flap. For example, a certain surface treatment process is adopted for the valve flap to directly enhance the cavitation resistance of the valve flap, or a cap-shaped protective sleeve is put on the valve flap to avoid the valve flap directly suffering from cavitation.

[0008] However, in the actual application process, these two solutions still have inevitable problems respectively.

[0009] The solution of adopting a surface treatment process for the valve flap means that the production cost of the valve flap will increase, thus increasing the equipment cost of the cut-off valve. And it still cannot avoid the valve flap from suffering from cavitation, but only prolongs the service life of the valve flap.

[0010] The solution of putting a cap-shaped protective sleeve on the valve flap means that when the cut-off valve cuts off the pipeline, the valve flap will tightly press the protective sleeve against the valve body. This pressing force will lead to an inevitable contradiction, that is, if the pressing force is too large, it can indeed ensure the cut-off function of the cut-off valve for the pipeline, but the protective sleeve may be damaged under the action of a large extrusion force. And if we want to ensure that the protective sleeve is not damaged under this extrusion force, we need to reduce the pressing force. However, reducing the pressing force will affect the reliability of the cut-off valve when applied to high-pressure fluid pipelines.

[0011] Based on the above description, therefore, a manual pneumatic emergency cut-off valve is proposed. Summary of the Invention

[0012] The purpose of the present invention is to provide a manual and pneumatic emergency cut-off valve. By setting a protective cover, during the process of opening / closing the cut-off valve, the valve flap can be received inside the protective cover, and the protective cover is used to replace the valve flap to be subjected to cavitation, thereby avoiding the wear of the valve flap caused by cavitation. At the same time, when the cut-off valve is already closed, the compensation unit is used to prevent the protective cover from being damaged due to the extrusion force, so as to solve the problems raised in the above background technology. Finally, the valve flap of the manual and pneumatic emergency cut-off valve can be effectively protected, thereby ensuring the reliability of the cut-off valve during the working process.

[0013] To achieve the above purpose, the present invention provides the following technical solutions:

[0014] A manual and pneumatic emergency cut-off valve, comprising:

[0015] A valve body, a manual device, a pneumatic device, a valve stem, and a valve flap;

[0016] The valve body is provided with a pneumatic device and a manual device. The pneumatic device is connected to an external air supply device. The air supply device controls the opening and closing state of the cut-off valve by charging and discharging air into the pneumatic device. The manual device controls the opening and closing state of the emergency cut-off valve by manual operation;

[0017] Both the valve stem and the valve flap are installed inside the valve body. The valve stem is connected to both the pneumatic device and the manual device, and the valve flap is installed at one end of the valve stem. A gate is provided inside the valve body that cooperates with the valve flap;

[0018] A protective cover is sleeved on the valve stem. The protective cover cooperates with the valve flap. When the valve flap enters the protective cover, the valve flap fits tightly with the inner side surface of the protective cover;

[0019] During the opening / closing process of the cut-off valve, the valve flap is received inside the protective cover, and the protective cover is used to replace the valve flap to be subjected to cavitation;

[0020] A limiting platform is fixed on the valve stem. A compensation unit is provided between the limiting platform and the protective cover for pressing the protective cover tightly against the gate inside the valve body in the closed state of the emergency cut-off valve.

[0021] The compensation unit includes a spring sleeved on the valve stem, and both ends of the spring are fixedly connected to the protective cover and the limiting platform respectively.

[0022] Based on this technical solution, taking the process of the shut-off valve changing from the open state to the closed state as an example, the basic working principle of the present invention is as follows: As the initial state, the protective cover presses on the valve flap, that is, the valve flap is received in the protective cover, abuts against the inner top of the protective cover, and at this time, the bottom end of the protective cover protrudes more towards the gate opening than the valve flap. During operation, first, through a pneumatic device or a manual device, the valve stem is made to push the valve flap towards the gate opening, causing the opening degree of the valve to gradually decrease. During this process, before the valve flap closes the gate opening, the bottom end of the protective cover first contacts the peripheral area of the gate opening. Subsequently, the valve flap continues to move downward, and the opening degree of the valve continues to decrease. Then, the spring is compressed under the action of the limiting platform, and the elastic force acts on the protective cover, pressing the protective cover tightly in the current position until the opening degree of the valve is zero. Thus, the shut-off valve completes the closing action.

[0023] Correspondingly, the process of the shut-off valve opening is that the valve flap moves upward and gradually falls into the protective cover, and a chamber for accommodating liquid is formed between the bottom end surface of the valve flap and the inner wall surface of the protective cover. During this process, the opening degree of the shut-off valve gradually increases, and the volume of the chamber also gradually increases. At the same time, due to the elastic force of the spring pressing the protective cover tightly at the gate opening, as the chamber increases, the liquid always fills the chamber until the valve stem drives the limiting platform to move upward by a certain height, and the elastic force of the spring cannot balance the pressure of the liquid. At this time, the protective cover lifts upward, creating a gap below, and thus the liquid can overflow outward from this gap, and the valve opens.

[0024] It can be found from the above description that whether during the process of the valve flap closing the gate opening or the process of the valve flap moving away from the gate opening, the protective cover always remains pressed tightly against the peripheral area of the gate opening and covers the gate inside. This means that only when the protective cover is opened is the shut-off valve truly opened.

[0025] The condition for the protective cover to open is specifically that when the height of the bottom end surface of the valve flap is lower than the height of the bottom end of the protective cover, the protective cover does not open, and only when the height of the bottom end surface of the valve flap is higher than the height of the bottom end of the protective cover (that is, when the valve flap is completely received inside the protective cover), the protective cover is opened.

[0026] Therefore, when the shut-off valve is opened, the area where the liquid pressure undergoes a sudden change is no longer on both sides with the valve flap as the boundary, but on both sides with the protective cover as the boundary. That is to say, when the shut-off valve is opened, the high-pressure liquid inside the protective cover rushes into the low-pressure space outside the protective cover through the gap below the protective cover. Thus, cavitation acts on the protective cover rather than the valve flap, thereby protecting the valve flap.

[0027] In addition, when the shut-off valve is in the closed state, the valve flap still serves as the closing member of the gate opening. Therefore, in fact, the protective cover only needs to withstand the pressure of the liquid from the inside to the outside during the process of opening or closing the valve. After the valve is fully opened or fully closed, it no longer needs to withstand the pressure of the liquid that intends to deform it. The reason is that when the valve is fully closed, the valve flap closes the gate opening. Naturally, it is the valve flap that bears the pressure of the liquid, and the protective cover does not need to bear it. When the valve is fully opened, the shut-off valve is filled with fluid, so the protective cover is in a balanced force state and is not easily deformed.

[0028] It should be noted that in the above description of the equipment of the present invention, there is obviously a problem, that is, high-pressure liquid may spray into the inner cavity of the protective cover above the valve flap through the gap between the valve flap and the protective cover. At this time, the valve flap will still be affected by cavitation. To prevent this situation from occurring, in this technical solution, further, the protective cover and the valve flap are mutually coordinated. That is to say, when the valve flap is received inside the protective cover, the valve flap is closely attached to the inner side surface of the protective cover to prevent the liquid from spraying into the inner cavity of the protective cover above the valve flap through the gap between the valve flap and the protective cover.

[0029] Specifically, at this time, the movement of the valve flap inside the protective cover is similar to the action of the hydraulic cylinder. Among them, the valve flap is similar to the piston of the hydraulic cylinder, the valve rod is the piston rod, and the protective cover is the cylinder body of the hydraulic cylinder. Based on this, in order to ensure the sealing effect, it is obvious that a sealing ring can also be installed on the side surface of the valve flap to seal the gap between the valve flap and the protective cover, thereby preventing the liquid from spraying out.

[0030] Preferably, the spring is provided with a pre-tightening force.

[0031] The reason for such a setting is that there is pressure and conveying speed during the conveying process of the liquid. Therefore, during the closing process of the shut-off valve, as the valve opening decreases, the protective cover gets closer and closer to the gate opening, and inevitably bears the impact of the liquid at its bottom position, that is, the liquid generates an upward force on the protective cover. Therefore, if the pre-tightening force is not set, the spring may be prematurely compressed due to this impact force, and then it cannot be ensured that the protective cover is pressed against the gate opening one step before the valve flap closes the gate opening and covers the gate inside it. Once this situation occurs, the protective function of the protective cover will be completely lost. Therefore, it is necessary to set a certain pre-tightening force for the spring.

[0032] Preferably, the spring is a conical spiral spring.

[0033] By setting the spring as a conical spiral spring, the spring can obtain a greater compression amount at the same length, which is beneficial to the application of preload, saves space in the valve body, and helps to reduce the volume of the cut-off valve. On this basis, the spring can also be selected as a rectangular spring to obtain excellent load-bearing capacity and further reduce the required volume of the spring, which is more conducive to reducing the volume of the cut-off valve.

[0034] Preferably, the compensation unit described above can also adopt another form, specifically: the compensation unit includes a diaphragm mounted on the valve stem, the diaphragm is annular, and the two ends of the diaphragm are respectively fixedly connected to the limit platform and the protective cover; the diaphragm, the valve stem, the limit platform and the protective cover together form a cavity for accommodating the fluid; a branch pipe is provided on the valve body, and the branch pipe is used to connect the valve body and the cavity near one end of the fluid source.

[0035] The effective cross-sectional area of ​​the valve disc that withstands the fluid pressure when the emergency shut-off valve is in the open state is A1, and the effective cross-sectional area of ​​the protective cover in the cavity that withstands the fluid pressure is A2, and A1≥A2.

[0036] The basic working principle of this compensation unit is: when fluid is passed into the cut-off valve, part of the valve body portion close to one end of the fluid source, that is, the part where the liquid in the cut-off valve is permanently located, will pass through the branch pipe into the cavity surrounded by the diaphragm, valve stem, limit platform and protective cover, thus forming a hydraulic zone, and then a pressure is generated on the protective cover in the cavity. This pressure can ensure that the protective cover can be pressed against the gate, which is equivalent to the effect of the preload force of the spring in the previous technical solution.

[0037] It should be noted that this method of pressing the protective cover against the valve gate has the following advantages: First, since the transmission of liquid pressure does not depend on the volume of the liquid, in fact, the volume of the cavity surrounded by the diaphragm, valve stem, limit platform and protective cover can obtain extremely small design dimensions at the design level, while ensuring the pressure transmission effect. More specifically, its volume can be much smaller than the volume occupied by the spring mentioned in the previous technical solution; second, since the liquid in the cavity is directly drawn from the pipeline, the pressure of the liquid acting on the protective cover is equal. Therefore, it is only necessary to design the area of ​​the protective cover in the cavity (the outer area of ​​the top of the protective cover) to be larger than the cross-sectional area of ​​its bottom end, so as to ensure that the downward pressure on the protective cover is always not less than the upward pressure during the process, thereby ensuring that in the process of closing the cut-off valve, the protective cover can always cover the gate mouth before the valve disc closes the gate mouth, thereby ensuring that the valve disc is not affected by cavitation.

[0038] On this basis, the effective cross-sectional area A1 of the valve flap under the fluid pressure in the open state of the emergency cut-off valve and the effective cross-sectional area of the protective cover in the cavity (i.e., the outer area at the top of the protective cover) A2 can be set such that the relationship between the two areas is: A1≥A2. In this way, the force-bearing situation of the structure of the present invention can be optimized, and further the service life of the equipment of the present invention can be extended. The specific explanation is as follows:

[0039] First of all, when the valve is in the open state, for the protective cover, the protective cover needs to bear a downward pressure acting on the outer side of its top from the cavity and an upward pressure acting on its bottom. According to the above description, the resultant force on the protective cover is a downward pressure F1; for the valve flap, the valve flap needs to bear an upward pressure F2 from the pipeline. If F1>F2, it will cause the valve flap to bear a downward force that makes it tend to break away from the valve stem. This force is obviously unnecessary and will ultimately act on the connecting part between the valve stem and the valve flap. Obviously, the size of this connecting part is smaller than the valve stem, so it is more likely to be damaged compared to the valve stem, and thus the valve flap will bear an additional risk of breaking away from the valve stem. To solve this problem, the above two areas are designed so that the two areas satisfy A1≥A2. Then, when the valve is in the open state, the resultant force borne by the valve flap is upward, that is, the direction in which the valve stem is compressed. At this time, the valve flap will always be subjected to a force in the direction in which the valve stem is compressed, so the connecting part between the valve flap and the valve stem is prevented from bearing unnecessary tensile force and being damaged, and the force-bearing situation of the structure is optimized.

[0040] Preferably, a soft pad is installed at the edge where the protective cover mates with the inner gate of the valve body.

[0041] During the working process of the present invention, for the purpose of protecting the valve flap, the protective cover is used to bear the influence of cavitation instead of the valve flap. Therefore, the part at the bottom of the protective cover that bears cavitation will inevitably be worn, resulting in a reduction in the height dimension of the protective cover. This will cause the force provided by the spring to press the protective cover against the gate of the cut-off valve to decrease (because the compression amount of the spring also decreases at this time). Then, during the opening process of the cut-off valve, as the limit platform moves upward, the protective cover may open earlier than expected, allowing high-pressure liquid to leak out. At this time, the height at which the valve flap lifts from the gate is obviously lower than the height expected in the original design, that is to say, the valve flap is closer to the area where cavitation occurs at this time, thus increasing the risk of the valve flap being subjected to cavitation.

[0042] Therefore, a soft pad is provided. When the protective cover is pressed tightly against the gate opening, the soft pad undergoes elastic deformation and adheres to the peripheral area at the gate opening, improving the sealing performance. At the same time, the soft pad plays a protective role for the protective cover, bearing the cavitation in place of the protective cover itself, avoiding the wear caused by the cavitation effect from affecting the height dimension of the protective cover. Furthermore, since the soft pad can undergo elastic deformation, as long as there is a certain amount of compression when the protective cover is pressed, even if the soft pad reduces in size due to wear, it can continue to compensate for the gap with the peripheral area at the gate opening through the recovery of its elastic deformation, thereby preventing the liquid from leaking out prematurely, and thus protecting the valve flap from the cavitation phenomenon.

[0043] It should be added that when high-pressure liquid sprays into the low-pressure space, due to factors such as the interference between droplets and the surface roughness of components, the droplets will not only affect the bottom end face of the protective cover, but also affect a part of the side wall surface above the bottom end face. That is to say, this part of the side wall surface of the protective cover will also be likely to bear the wear of the cavitation phenomenon, which will then lead to the thinning of the protective cover, and thus the protective cover may deform or even be damaged when subjected to the spring pressure. To avoid this problem and ensure the protective effect of the soft pad on the protective cover, the bottom end of the protective cover can be wrapped with a soft pad. The specific setting can be: using a ring-shaped soft pad, and the overall cross-section of the soft pad presents a shape similar to a U shape, and the concave inner surface of the U shape is used to wrap the bottom end of the protective cover. In this way, the soft pad not only protects the bottom end face of the protective cover, but also protects a part of the edge above the bottom end. Therefore, the soft pad has a protective effect on a part of the side wall surface above the bottom end of the protective cover.

[0044] It is true that by directly increasing the pre-tightening force of the spring, a function similar to that of the soft pad can also be achieved through the spring. However, in order to ensure that the spring can press the protective cover tightly in the limited space within the cut-off valve, it means that a spring with a large elastic modulus needs to be selected. At this time, the difficulty of adjusting the spring pre-tightening force is obviously greatly increased. The reason is that even a small amount of deformation can bring a large change in the pre-tightening force. For the soft pad, since its main functions are buffering and gap compensation, its elastic modulus can be selected to be smaller compared to the spring. Therefore, only a suitable soft pad needs to be selected, without adjusting the spring pre-tightening force, which simplifies the adjustment work of the present invention.

[0045] Correspondingly, it can also be found that for the compensation unit that presses the protective cover with liquid pressure, this problem obviously does not exist. Then, the main function of the soft pad at this time is to protect the protective cover from cavitation wear.

[0046] In addition, it is worth noting that the soft pad can be made of soft sealing materials used in conventional liquid seals. According to the actual application conditions such as the pressure in the pipeline, materials such as polyurethane and rubber can be used.

[0047] Preferably, the soft pad has an arc surface. When the protective cover is pressed against the gate at the inner part of the valve body, the arc surface of the soft pad contacts the inner side wall of the valve body.

[0048] The reason for such a setting is that when the protective cover is pressed against the peripheral area at the gate, the soft pad will obviously be compressed and deformed inevitably. Since the deformed soft pad can only have deformation amounts on the inner and outer sides of the protective cover, it is very likely to protrude towards the gate direction. At this time, the soft pad will instead hinder the movement of the valve flap. Therefore, it is necessary to avoid this situation. By setting the soft pad to have an arc surface, when the protective cover is pressed on the area around the gate, during the deformation process of the soft pad, the deformation amount of the soft pad towards the inside of the protective cover can be reduced, thereby reducing or even eliminating the hindering effect of the soft pad on the movement of the valve flap.

[0049] Finally, for the specific forms of the two compensation units mentioned in the foregoing, it can be found that they can both ensure that the pressure borne by the protective cover has a constant upper limit, rather than increasing continuously with the increase of the force pressing the valve flap against the gate, but will reach the upper limit when the gate is closed by the valve flap. This means that as long as the pressure parameter in the pipeline is determined when designing and selecting the equipment of the present invention, the protective cover will not be damaged due to excessive extrusion force. For easy understanding, the following is a specific example:

[0050] For the compensation unit using a spring, after the valve flap is pressed on the gate and the manual device is continuously operated to press down the valve flap to make it tightly pressed, since both the valve body and the valve flap are objects with large stiffness, the downward displacement amount of the valve flap is actually very small and can almost be ignored, but it will cause the valve flap to obtain a large pressing force, thereby ensuring the closure of the gate. At the same time, the downward displacement of the limit platform is also very small. Therefore, it can be approximately considered that the elastic force of the spring is constant. Thus, it can be considered that the pressing force borne by the protective cover reaches the upper limit at this time. Therefore, as long as a suitable spring is selected, the protective cover will not be damaged due to the extrusion force.

[0051] For the compensation unit using components such as a diaphragm and a branch pipe and utilizing the fluid pressure in the pipeline, it is easy to find that the pressing force borne by the protective cover is only related to the fluid pressure in the pipeline. Therefore, it also has an upper limit. Thus, as long as suitable A1 and A2 are selected according to the fluid pressure in the pipeline, the protective cover will not be damaged due to the extrusion force.

[0052] In view of the content mentioned in the foregoing, to further dispel doubts, it should be added that when the protective cover is pressed near the gate, it is not required to be able to completely block the fluid from passing through, but has a certain tolerance as long as it is ensured that the fluid can always fill the space enclosed by the valve flap and the inner side wall of the protective cover. And this tolerance can actually also reduce the difficulty in the selection of the spring and the design of A1 and A2.

[0053] In summary, compared with the prior art, the advantages of the present invention are as follows:

[0054] 1. By providing a cavitation prevention device with a spring as a compensation unit, during the process of opening / closing the cut-off valve, the valve flap can be received inside the protective cover, and the protective cover is used to replace the valve flap to be subjected to cavitation, thereby avoiding the wear of the valve flap caused by cavitation. At the same time, when the cut-off valve is in the closed state, the valve flap is still used as the closing member of the gate opening. Therefore, in fact, the protective cover only needs to bear the pressure of the liquid from the inside to the outside during the process of opening or closing the valve, and after the valve is fully opened or fully closed, it no longer needs to bear the pressure of the liquid that intends to deform it, thereby improving the reliability of the present invention and extending the service life of the present invention.

[0055] 2. By providing a cavitation prevention device with the liquid pressure in the pipeline itself as a compensation unit, when the cut-off valve is opened or closed, the protective cover covers the valve flap inside to prevent cavitation from wearing the valve flap. At the same time, this device can obtain a smaller design size, which is beneficial to reducing the design volume of the present invention; in addition, since the liquid providing hydraulic pressure is directly introduced from the pipeline inside, and the area of the protective cover in the cavity (the outer area at the top of the protective cover) is larger than the cross-sectional area at its bottom, the downward pressure on the protective cover is always not less than the upward pressure. Therefore, during the process of closing the cut-off valve, the protective cover can always cover the gate opening inside it one step before the valve flap closes the gate opening, thereby ensuring that the valve flap is not affected by cavitation, and thus improving the working reliability of the equipment of the present invention.

[0056] 3. By providing a soft pad, the protective cover is protected by the soft pad, avoiding the wear of the cavitation effect from affecting the height dimension of the protective cover. Furthermore, since the soft pad can undergo elastic deformation, as long as there is a certain amount of compression when the protective cover is pressed, even if the soft pad has a reduced size due to wear, it can continue to compensate for the gap between it and the surrounding area at the gate opening through the recovery of the elastic deformation of the soft pad, thereby preventing the liquid from leaking out prematurely, and thus protecting the valve flap from the cavitation phenomenon. Additionally, by setting the soft pad to have an arc-shaped surface, even if the soft pad is deformed, it will not hinder the movement of the valve flap, thereby improving the reliability of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0058] Figure 2 is a front view in a plane of the cut-off valve in the closed state in the first embodiment of the present invention;

[0059] Figure 3 is a front view in a plane of the cut-off valve in the open state in the first embodiment of the present invention;

[0060] Figure 4 is Figure 3 an enlarged view of part A in

[0061] Figure 5 the front plan view of the shut-off valve in the closed state according to the second embodiment of the present invention;

[0062] Figure 6 is Figure 5 an enlarged view of part B in

[0063] Figure 7 the front plan view of the shut-off valve in the open state according to the second embodiment of the present invention.

[0064] In the figure: 1, manual device; 2, pneumatic device; 3, valve body; 30, gate; 31, valve stem; 32, valve flap; 33, limit platform; 34, protective cover; 35, spring; 36, diaphragm; 37, branch pipe; 341, soft pad. Specific embodiments

[0065] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention.

[0066] Embodiment 1:

[0067] As Figures 1 to 4 shown, the first specific embodiment of the present invention is shown. The compensation unit used in this embodiment is the spring 35. In this embodiment, the viewing angle shown in Figure 2 is used to determine directions such as "up", "down", "left", and "right".

[0068] As preparations before the installation of the present invention, it should be noted that: First, the manual device 1, pneumatic device 2, valve body 3, valve stem 31 and the mating installation relationship among the four belong to well-known technologies, so their installation and principles will not be elaborated here; Second, in order to facilitate the installation of internal components, an opening is provided at the bottom end of the valve body 3 and is equipped with an end cover for closing the opening; Third, the limit platform 33 is pre-welded on the valve stem 31 and has a buckle for installing the spring 35; Fourth, in order to apply the pre-tightening force of the spring 35, the spring 35 is selected so that when the valve flap 32 is fixed to the lower end of the valve stem 31 and the shut-off valve is in the open state, it just has an appropriate pre-tightening force; Fifth, the soft pad 341 is pre-coated on the lower end of the protective cover 34 and fixed by means of threaded connection; Sixth, a sealing ring (not shown in the figure) is installed on the side wall surface of the valve flap 32 to seal the gap between the valve flap 32 and the protective cover 34.

[0069] When the present invention is installed, first, when the shut-off valve is installed, the valve stem 31 is in the highest position, that is, the shut-off valve is in the action position when it is in the open state at this time. The manual device 1, the pneumatic device 2, the valve body 3 and the valve stem 31 are pre-assembled and installed. Then, the end cover on the valve body 3 is removed, and the spring 35 is sleeved on the valve stem 31 from the pipeline interface on the left side of the valve body 3, and the spring 35 is fixedly installed on the limit platform 33 by a snap-fit ​​method. Then, the protective cover 34 is sleeved on the valve stem 31, and the protective cover 34 is fixedly connected to the lower end of the spring 35 by a snap-fit ​​method. Next, the valve flap 32 is installed to the lower end of the valve stem 31 by a threaded connection, and the valve flap 32 is located inside the protective cover 34. Finally, the end cover of the valve body 3 is re-installed back to the lower end of the valve body 3 by a threaded connection. At this point, the present invention is installed.

[0070] When the present invention is working, it is divided into two action processes: closing and opening:

[0071] First, when the present invention is closed, the pneumatic device 2 is used to make the valve stem 31 push the valve flap 32 toward the gate 30, so that the opening of the valve gradually becomes smaller. In this process, before the valve flap 32 closes the gate 30, the bottom end of the protective cover 34 first contacts the surrounding area of ​​the gate 30. Then, the valve flap 32 continues to move downward, and the opening of the valve continues to decrease. Therefore, the spring 35 is compressed under the action of the limit platform 33, and the elastic force acts on the protective cover 34, pressing the protective cover 34 to the current position until the opening of the valve is zero. At this point, the present invention completes the closing action.

[0072] When the present invention is opened, the valve flap 32 moves upward through the pneumatic device 2 and extends into the protective cover 34. The bottom end surface of the valve flap 32 and the inner wall surface of the protective cover 34 form a chamber for accommodating liquid. During this process, the opening of the cut-off valve gradually increases, and the volume of the chamber also gradually increases. At the same time, the elastic force of the spring 35 presses the protective cover 34 against the gate 30. As the chamber increases, the liquid continues to fill the chamber until the valve stem 31 moves up a certain height with the limit platform 33, and the valve flap 32 abuts against the protective cover 34, so that the protective cover 34 is lifted upward by the valve flap 32. At this time, the protective cover 34 is lifted upward to form a gap below, so that the liquid can overflow from the gap, and the valve opens until the valve stem 31 reaches the highest position and the valve is fully opened.

[0073] After the present invention is closed, no leakage occurs in the pipeline and the liquid flow pipeline is cut off; after the present invention is fully opened, the liquid flow path is restored in the pipeline and the device of the present invention does not vibrate significantly.

[0074] Embodiment 2:

[0075] like Figure 1 ,as well as Figures 5 to 7, which shows a second specific embodiment of the present invention. The difference between this embodiment and the first embodiment is that the compensation unit used in this embodiment is a structure composed of a protective cover 34, a diaphragm 36, a limit table 33, and a branch pipe 37. Among these components, the remaining components except the branch pipe 37 and the valve stem 31 form a cavity for accommodating liquid. The branch pipe 37 is used to introduce liquid into the cavity or discharge the liquid in the cavity, and a sealing ring (not shown in the figure) is installed in the gap between the protective cover 34 and the valve stem 31 to prevent liquid from leaking downward.

[0076] In addition, three points are added: first, in the present embodiment, the material of the diaphragm 36 is nitrile rubber; second, the diaphragm 36 is connected to the limit platform 33 and the protective cover 34 respectively by threaded connection; third, since the protective cover 34 is sleeved on the valve stem 31, A1 is actually an annular area.

[0077] In this embodiment, when the present invention is working, it is divided into two processes: closing and opening:

[0078] When the present invention is closed, the pneumatic device 2 is used to make the valve stem 31 push the valve flap 32 toward the gate 30, so that the opening of the valve gradually becomes smaller. In this process, before the valve flap 32 closes the gate 30, the bottom end of the protective cover 34 first contacts the peripheral area of ​​the gate 30. Then, the valve flap 32 continues to move downward, so that the protective cover 34 no longer rests on the valve flap 32. Therefore, the valve flap 32 no longer provides the protective cover 34 with a supporting force to resist the hydraulic pressure in the cavity. Then, the hydraulic pressure in the cavity presses the protective cover 34 to the position of the gate 30 until the opening of the valve is zero. At this point, the present invention completes the closing action.

[0079] When the present invention is opened, the valve flap 32 moves upward through the pneumatic device 2 and extends into the protective cover 34. The bottom end surface of the valve flap 32 and the inner wall surface of the protective cover 34 form a chamber for accommodating liquid. During this process, the opening of the cut-off valve gradually increases, and the volume of the chamber also gradually increases. At the same time, the liquid pressure provided by the liquid in the chamber presses the protective cover 34 against the gate 30. As the chamber increases, the liquid continues to fill the chamber until the valve stem 31 moves up a certain height with the limit platform 33. The valve flap 32 abuts against the inner top of the protective cover 34 and lifts the protective cover 34. At this time, the protective cover 34 is lifted upward to form a gap below, so that the liquid can overflow from the gap, and the valve opens until the valve stem 31 reaches the highest position and the valve is fully opened. It should be added that, when the volume of the cavity decreases, the excess liquid returns to the main pipe of the valve body 3 through the branch pipe 37; conversely, when the volume of the cavity increases, the liquid enters the cavity from the main pipe of the valve body 3 through the branch pipe 37.

[0080] The effects of this embodiment are the same as those of the first embodiment.

[0081] However, it is worth noting that in the second embodiment, since the time when the valve flap 32 leaves the protective cover 34 can be regarded as instantaneous, the pressing force (i.e., the liquid pressure) provided by the liquid pressure to the protective cover 34 to press the protective cover 34 against the gate 30 reaches the maximum value instantaneously; while the pressing force given by the spring 35 in the first embodiment to the protective cover 34 changes gradually with the deformation of the spring 35. Therefore, to achieve the same closing effect, the action speed of the compensation unit in the second embodiment is faster.

[0082] However, in the first embodiment, using the spring 35 as the compensation unit also has its advantages. The advantages are that the structure is simple and reliable and does not require frequent maintenance. This is because, in the second embodiment, to ensure the accuracy and stability of the liquid pressure in the cavity, it is necessary to ensure that the cavity has a certain sealing performance, which will introduce necessary sealing structures. In the second embodiment, the sealing structure is the sealing ring installed at the gap between the valve stem 31 and the protective cover 34. This means that there is one more component that may be damaged. At the same time, the diaphragm 36 may also fail due to fatigue damage during the use of the valve, thereby causing the sealing performance of the cavity to be damaged, and ultimately resulting in the failure of the device of the present invention. However, these problems do not need to be considered when using the spring 35 as the compensation unit.

[0083] Although the beneficial effects of the present invention have been shown in detail and embodiments have been provided in this specification, for those of ordinary skill in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A manual and pneumatic emergency cut-off valve, comprising: A valve body (3), a manual device (1), a pneumatic device (2), a valve stem (31), and a valve flap (32); The pneumatic device (2) and the manual device (1) are arranged on the valve body (3). The pneumatic device (2) is connected to an external gas supply device. The gas supply device controls the opening and closing state of the cut-off valve by charging and discharging gas to the pneumatic device (2). The manual device (1) controls the opening and closing state of the emergency cut-off valve by manual operation; Both the valve stem (31) and the valve flap (32) are installed inside the valve body (3). The valve stem (31) is connected to both the pneumatic device (2) and the manual device (1), and the valve flap (32) is installed at one end of the valve stem (31). A gate opening (30) that cooperates with the valve flap (32) is arranged inside the valve body (3); It is characterized in that: A protective cover (34) is sleeved on the valve stem (31). The protective cover (34) cooperates with the valve flap (32). When the valve flap (32) enters the protective cover (34), the valve flap (32) is in close fit with the inner side surface of the protective cover (34); During the opening / closing process of the cut-off valve, the valve flap (32) is received inside the protective cover (34), and the protective cover (34) is subjected to cavitation instead of the valve flap (32); A limiting platform (33) is fixed on the valve stem (31). A compensation unit is arranged between the limiting platform (33) and the protective cover (34) for pressing the protective cover (34) against the gate opening (30) inside the valve body (3) in the closed state of the emergency cut-off valve.

2. The manual and pneumatic emergency cut-off valve according to claim 1, wherein: The compensation unit includes a spring (35) sleeved on the valve stem (31), and both ends of the spring (35) are fixedly connected to the protective cover (34) and the limiting platform (33) respectively.

3. A manual and pneumatic emergency cut-off valve according to claim 2, characterized in that: The spring (35) is provided with a pre-tightening force.

4. A manual and pneumatic emergency cut-off valve according to claim 2, characterized in that: The spring (35) is a conical helical spring.

5. A manual pneumatic emergency cut-off valve according to claim 1, characterized in that: The compensation unit includes a diaphragm (36) sleeved on the valve stem (31). The diaphragm (36) is annular, and both ends of the diaphragm (36) are fixedly connected to the limiting platform (33) and the protective cover (34) respectively; A cavity for accommodating fluid is jointly formed by the diaphragm (36), the valve stem (31), the limiting platform (33), and the protective cover (34); A branch pipe (37) is arranged on the valve body (3). The branch pipe (37) is used to connect the cavity and the flow channel at one end of the valve body (3) close to the fluid source.

6. The manual pneumatic emergency cut-off valve according to claim 5, characterized in that: The effective cross-sectional area of the valve flap (32) bearing the fluid pressure in the open state of the emergency cut-off valve is A1, and the effective cross-sectional area of the protective cover (34) in the cavity bearing the fluid pressure is A2, and A1 = A2.

7. A manual and pneumatic emergency cut-off valve according to claim 2 or 5, characterized in that: A soft pad (341) is installed at the edge where the protective cover (34) cooperates with the gate opening (30) inside the valve body (3).

8. A manual and pneumatic emergency cut-off valve according to claim 7, characterized in that: The soft pad (341) wraps the edge where the protective cover (34) cooperates with the gate opening (30) inside the valve body (3).

9. The manual pneumatic emergency cut-off valve according to claim 7, characterized in that: The soft pad (341) has an arc-shaped surface. When the protective cover (34) is pressed against the gate opening (30) inside the valve body (3), the arc-shaped surface of the soft pad (341) contacts the inner side wall of the valve body (3).

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