Check valve for negative pressure environment and vacuum creating system

Abstract

The invention discloses a check valve for a negative pressure environment. The check valve comprises a valve body, a valve element assembly and a diaphragm assembly. When the difference value obtained by subtracting the air pressure of the air inlet section of the valve body from the air pressure of the air outlet section of the valve body exceeds a set threshold value, the diaphragm assembly can overcome the resistance from the reset spring and the resistance from the air in the air outlet section with the help of the air entering the air inlet section, and the valve element assembly is pushed to move from the position where the opening is blocked to the position where the opening is opened. When the difference value obtained by subtracting the air pressure of the air outlet section from the air pressure of the air inlet section is equal to or lower than a set threshold value, a reset spring of the valve element assembly can overcome the resistance from the diaphragm assembly and the resistance from the air in the air inlet section with the help of the air entering the air outlet section. And the valve core assembly is pushed to return to the position for blocking the opening from the position for opening the opening. The check valve can timely block the communication between the forestage vacuum side and the molecular pump, so that the overall performance of the molecular pump is improved, and the service life of the molecular pump is prolonged.

Description

Technical Field

[0001] Embodiments of the present invention relate to the technical field of check valves for negative pressure environments, and more particularly, the present invention relates to a check valve for negative pressure environments and a vacuum creation system. Background Art

[0002] In the field of vacuum technology, molecular pumps are key equipment for achieving vacuum environments. The stability and reliability of their performance are crucial to maintaining the normal operation of the vacuum system in which the molecular pumps are located. Molecular pumps efficiently compress and discharge gas molecules through internal high-speed rotating components (such as turbine rotor blades) to achieve the required vacuum level. However, molecular pumps may face serious challenges in the event of certain failures or operational errors. Specifically, in order for the molecular pump to efficiently compress and discharge gas molecules, it is also necessary to connect the molecular pump to a vacuum pump to form a vacuum creation system to meet the needs of creating a vacuum environment.

[0003] In order to ensure the stability of the molecular pump structure and safe operation, the vacuum creation system also includes a check valve that is located between the molecular pump and the vacuum pump and connects the two. The check valve is in a negative pressure environment formed by the vacuum pump and the molecular pump. However, in actual applications, if the vacuum pump connected to the molecular pump is suddenly exposed to the atmospheric environment (such as a leak in the vacuum pump), due to the huge difference between the atmospheric pressure and the extremely low vacuum maintained inside the molecular pump, this sudden pressure change will cause a strong airflow shock in an instant. Unfortunately, the common check valves on the market are often difficult to respond quickly in such a tight time and adapt to this sudden pressure change to achieve closure. The result of this delayed reaction is that the strong airflow shock directly acts on the rotating components inside the molecular pump, causing the rotating components to deform or break, which seriously affects the overall performance and service life of the molecular pump. Summary of the invention

[0004] In order to solve one or more of the technical problems mentioned above, the present invention provides a check valve and a vacuum creation system for a negative pressure environment, which can promptly block the connection between the front-stage vacuum side and the molecular pump when the front-stage vacuum side is suddenly exposed to the atmospheric environment, thereby preventing the rotating components inside the molecular pump from being deformed or broken, thereby improving the overall performance and service life of the molecular pump.

[0005] According to a first aspect of the present invention, there is provided a check valve for a negative pressure environment, the check valve comprising: a valve body, comprising an inner cavity, a partition structure fixedly arranged in the inner cavity and dividing it into an air inlet section and an air outlet section, an inlet connected to the air inlet section of the inner cavity, and an outlet connected to the air outlet section of the inner cavity, wherein the partition structure has an opening for connecting the air inlet section and the air outlet section; a valve core assembly, comprising a valve core arranged in the inner cavity and used to open or block the opening, and a return spring arranged in the valve body and abutting or connected to the valve core; and a diaphragm assembly, which is partially exposed on the valve body and can increase the pressure on the valve core assembly according to the increase of the pressure difference between the inside and the outside of the valve body. force; wherein, when the difference between the air pressure in the air inlet section and the air pressure in the air outlet section exceeds a set threshold value, the gas entering the air inlet section can, with the help of the diaphragm assembly, overcome the resistance from the return spring and the resistance from the gas in the air outlet section, and push the valve core assembly to move from a position blocking the opening to a position opening the opening; when the difference between the air pressure in the air inlet section and the air pressure in the air outlet section is equal to or lower than the set threshold value, the return spring can, with the help of the gas entering the air outlet section, overcome the resistance from the diaphragm assembly and the resistance from the gas in the air inlet section, and push the valve core assembly to return from a position opening the opening to a position blocking the opening.

[0006] The check valve for negative pressure environment provided in this embodiment realizes opening or blocking the opening of the partition structure through the cooperation of the valve core assembly and the diaphragm assembly, thereby realizing the blocking and connection between the outlet section and the inlet section of the valve body. Among them, the diaphragm assembly can respond quickly to the pressure difference on both sides of the diaphragm assembly, so it is arranged between the inner cavity of the valve body and the external environment, so that when the vacuum pump is suddenly exposed to the atmospheric environment, the opening can be blocked in time with the return spring of the valve core assembly, thereby avoiding the strong airflow impact directly acting on the rotating components (such as the turbine rotor blades of the molecular pump) inside the molecular pump through the outlet section and the inlet section of the check valve, reducing the risk of deformation or breakage of the rotating components, ensuring the overall performance of the molecular pump, and improving the service life of the molecular pump.

[0007] It should be noted that in the vacuum field, the pressure difference between the air inlet section and the air outlet section in the valve body is relatively small (for example, 100 pa), which makes it extremely difficult to find a reset spring that can respond to this pressure difference and drive the valve core to open or block the opening of the partition structure, and it is even unclear whether it exists in reality. On this basis, if the check valve only relies on the reset spring to drive the valve core to open or block the opening of the partition structure, when the molecular pump and the vacuum pump are in working state, the gas in the air inlet section of the valve body is difficult to cause the reset spring to be compressed, and it is difficult to maintain the opening open. As a result, the check valve cannot be opened when the molecular pump and the vacuum pump are in working state. However, after the diaphragm assembly is introduced, the diaphragm assembly can respond to the pressure difference between the inside and outside of the valve body (especially the air outlet section and the outside of the valve body) and choose to assist the gas in the air inlet section, so that the gas in the air inlet section can overcome the resistance from the reset spring with the help of the diaphragm assembly, and push the valve core assembly from the position of blocking the opening to the position of opening the opening, thereby realizing the opening of the check valve.

[0008] According to a second aspect of the present invention, a vacuum creation system is provided, which includes a molecular pump, a check valve connected to the molecular pump, and a vacuum pump connected to the check valve, which are arranged in sequence along the gas flow direction, and the check valve is the above-mentioned check valve.

[0009] The vacuum creation system provided in this embodiment can timely block the connection between the fore-stage vacuum side and the molecular pump when the fore-stage vacuum side is suddenly exposed to the atmospheric environment, thereby preventing the rotating components inside the molecular pump from being deformed or broken, thereby improving the overall performance and service life of the molecular pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] By reading the following detailed description with reference to the accompanying drawings, the above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood. In the accompanying drawings, several embodiments of the present invention are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0011] Figure 1 A schematic structural diagram of a check valve for use in a negative pressure environment provided by an embodiment of the present invention is shown;

[0012] Figure 2 A schematic diagram showing the structure of a check valve in a gas flow state provided by an embodiment of the present invention;

[0013] Figure 3 A schematic diagram showing the structure of a check valve in a blocked gas state provided by an embodiment of the present invention is shown;

[0014] Figure 4 A schematic diagram showing the structure of the valve core assembly and the diaphragm assembly in a gas flow state provided by an embodiment of the present invention;

[0015] Figure 5 A schematic diagram showing the structure of the valve core assembly and the diaphragm assembly in a blocked state provided by an embodiment of the present invention is shown;

[0016] Figure 6 A bottom view of a check valve provided by an embodiment of the present invention is shown;

[0017] Figure 7 A schematic structural diagram of an elastic diaphragm provided in an embodiment of the present invention is shown;

[0018] Figure 8 A top view of a check valve provided by an embodiment of the present invention is shown;

[0019] Fig. 9 A schematic structural diagram of a sealing cover provided by an embodiment of the present invention is shown.

[0020] In the figure:

[0021] 1. valve body; 11. inner cavity; 111. air inlet section; 112. air outlet section; 12. partition structure; 121. opening; 122. partition body; 123. bulge; 13. inlet; 14. outlet; 15. first radial hole; 16. pressing block; 161. central through hole; 17. second radial hole; 18. cover; 181. positioning groove; 182. annular groove;

[0022] 2. Valve core assembly; 21. Valve core; 211. Plug; 212. Sliding rod; 213. Baffle; 214. Adjusting nut; 22. Return spring;

[0023] 3. Diaphragm assembly; 31. Elastic diaphragm; 311. Diaphragm body; 312. Boss; 313. Limiting groove; 32. Connecting member; 321. Membrane connecting part; 322. Core connecting part; 323. Bending part;

[0024] 4. First fastening bolt;

[0025] 5. Second tightening bolt. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present disclosure.

[0027] This embodiment provides a vacuum creation system, which includes a molecular pump, a check valve connected to the molecular pump, and a vacuum pump connected to the check valve, which are arranged in sequence along the gas flow direction. When creating a vacuum in a certain environment, the vacuum pump is first started to generate a fore pressure, and then the molecular pump is started to generate pressure to achieve the creation of a vacuum environment.

[0028] The vacuum creation system provided in this embodiment can promptly block the connection between the front-stage vacuum side and the molecular pump when the front-stage vacuum side is suddenly exposed to the atmospheric environment (such as leakage in the vacuum pump), thereby preventing the rotating components inside the molecular pump from deforming or breaking, thereby improving the overall performance and service life of the molecular pump.

[0029] It should be noted that the vacuum pump and the molecular pump are conventional settings known to those skilled in the art, so the specific structures of the vacuum pump and the molecular pump and the specific connection with the check valve are not described in detail. Any vacuum pump and molecular pump that can achieve the above-mentioned vacuum environment should be within the protection scope of the embodiments of the present disclosure.

[0030] Figure 1 FIG. 1 shows a schematic structural diagram of a check valve for use in a negative pressure environment provided by this embodiment. Figure 2 The schematic diagram of the structure of the check valve in the gas flow state provided by this embodiment is shown. Figure 3 FIG. 2 shows a schematic diagram of the structure of the check valve provided in this embodiment when the gas is blocked. Figure 1-Figure 3As shown, this embodiment provides a check valve for a negative pressure environment, which is applied to the aforementioned vacuum creation system and is respectively connected to the aforementioned vacuum pump and the aforementioned molecular pump. The check valve includes a valve body 1, a valve core assembly 2, and a diaphragm assembly 3. The valve body 1 includes an inner cavity 11, a partition structure 12 fixedly arranged in the inner cavity 11 and dividing it into an air inlet section 111 and an air outlet section 112, an inlet 13 connected to the air inlet section 111 of the inner cavity 11, and an outlet 14 connected to the air outlet section 112 of the inner cavity 11, wherein the partition structure 12 has an opening 121 for connecting the air inlet section 111 and the air outlet section 112. The valve core assembly 2 includes a valve core 21 arranged in the inner cavity 11 and used to open or block the opening 121, and a return spring 22 arranged in the valve body 1 and abutting or connected to the valve core 21. The diaphragm assembly 3 is partially exposed on the valve body 1, and can increase the force acting on the valve core assembly 2 according to the increase of the pressure difference between the inside and outside of the valve body 1. When the difference between the air pressure of the air inlet section 111 and the air pressure of the air outlet section 112 exceeds a set threshold value (for example, 0.1-0.4N), the diaphragm assembly 3 can overcome the resistance from the return spring 22 and the resistance from the gas in the air outlet section 112 with the help of the gas entering the air inlet section 111, and push the valve core assembly 2 from the position of blocking the opening 121 to the position of opening the opening 121. When the difference between the air pressure of the air inlet section 111 and the air pressure of the air outlet section 112 is equal to or lower than the set threshold value, the return spring 22 can overcome the resistance from the diaphragm assembly 3 and the resistance from the gas in the air inlet section 111 with the help of the gas entering the air outlet section 112, and push the valve core assembly 2 from the position of opening the opening 121 to the position of blocking the opening 121.

[0031] When the molecular pump is in normal working condition, the vacuum pump makes the air outlet section 112 in the valve body 1 in a negative pressure environment, and the diaphragm assembly 3 moves due to the large air pressure difference between the inside and outside of the valve body 1 and causes the valve core assembly 2 to move. Moreover, since there is also an air pressure difference between the air inlet section 111 and the air outlet section 112 (that is, the difference between the air pressure of the air inlet section 111 and the air pressure of the air outlet section 112, and the difference between the two exceeds the set threshold at this time), at this time, the gas entering the air inlet section 111 can easily overcome the elastic force of the return spring 22 of the valve core assembly 2 with the help of the diaphragm assembly 3, thereby pushing the valve core 21 of the valve core assembly 2 to open the opening 121 of the partition structure 12, and then allowing the gas in the air inlet section 111 to enter the air outlet section 112 to achieve the purpose of connecting the vacuum pump with the molecular pump. When the opening 121 is opened, the force of the diaphragm assembly 3 acting on the valve core assembly 2 is in a balanced state with the elastic force of the return spring 22, the gravity of the return spring 22 itself and the restoring force of the diaphragm assembly 3 acting on the valve core assembly 2, so as to keep the opening 121 in a stable open state at all times.

[0032] It should be noted that after the opening 121 is opened, the difference between the air pressure in the outlet section 112 and the air pressure in the inlet section 111 can be eliminated almost instantly, and the difference between the two can even be negligible. In summary, the threshold value described in this embodiment only refers to a preset value of the valve core assembly 2 that changes according to the difference in air pressure between the inlet section 111 and the outlet section 112 before the opening 121 is opened.

[0033] When the vacuum pump is suddenly exposed to the atmospheric environment, the air pressure of the air outlet section 112 increases rapidly in a very short period of time, causing the air pressure difference between the inside and outside of the valve body 1 to decrease compared to the air pressure difference of the molecular pump in the normal working state. The diaphragm assembly 3 is affected by the air pressure difference and gradually returns to its original state to reduce the resistance to the reset spring 22. Since there is also an air pressure difference between the air inlet section 111 and the air outlet section 112 (that is, the difference between the air pressure of the air inlet section 111 and the air outlet section 112, and the difference between the two is less than or equal to the set threshold at this time), at this time, the reset spring 22 overcomes the resistance of the gas from the diaphragm assembly 3 and the air inlet section 111 under the influence of the air pressure difference between the diaphragm assembly 3 and the air inlet section 111 and the air outlet section 112, thereby pushing the valve core 21 of the valve core assembly 2 to block the opening 121 of the partition structure 12, thereby isolating the air inlet section 111 from the air outlet section 112 to achieve the purpose of blocking the connection between the vacuum pump and the molecular pump. When the opening 121 is just blocked, the diaphragm assembly 3 no longer exerts a force on the valve core assembly 2, and the elastic force of the return spring 22 and the gravity of the return spring 22 acting on the valve core assembly 2 are in a balanced state with the air pressure of the air inlet section 111. It should be noted that when the opening 121 is just blocked, the air pressure of the air outlet section 112 may be greater than the air pressure of the air inlet section 111, but the air pressure of the air outlet section 112 is less than the standard atmospheric pressure, so as to achieve an early response to the change of the air pressure of the air outlet section 112. If the air pressure of the air outlet section 112 continues to increase, the difference between the air outlet section 112 and the standard atmospheric pressure outside the valve body 1 is gradually reduced, causing the force of the diaphragm assembly 3 on the valve core assembly 2 to gradually decrease. At this time, the return spring 22 is subjected to a gradually reduced resistance, which can make the valve core assembly 2 more and more pressed against the partition structure 12.

[0034] The check valve for negative pressure environment provided in this embodiment realizes opening or blocking of the opening 121 of the partition structure 12 through the cooperation of the valve core assembly 2 and the diaphragm assembly 3, thereby realizing the blocking and connection between the outlet section 112 and the inlet section 111 of the valve body 1. Among them, the diaphragm assembly 3 can respond quickly to the pressure difference on both sides of the diaphragm assembly 3, so it is arranged between the inner cavity 11 of the valve body 1 and the external environment, so that when the vacuum pump is suddenly exposed to the atmospheric environment, the opening 121 is blocked in time with the return spring 22 of the valve core assembly 2, thereby preventing the strong air flow impact from directly acting on the rotating components (such as the turbine rotor blades of the molecular pump) inside the molecular pump through the outlet section 112 and the inlet section 111 of the check valve, reducing the risk of deformation or breakage of the rotating components, ensuring the overall performance of the molecular pump, and improving the service life of the molecular pump.

[0035] It should be noted that in the vacuum field, the pressure difference between the air inlet section 111 and the air outlet section 112 in the valve body 1 is relatively small (e.g., 100 pa), which makes it extremely difficult to find the return spring 22 that can respond to this pressure difference and drive the valve core 21 to open or block the opening 121 of the partition structure 12, and it is even unclear whether it exists in reality. On this basis, if the check valve only relies on the return spring 22 to drive the valve core 21 to open or block the opening 121 of the partition structure 12, when the molecular pump and the vacuum pump are in the working state, the gas in the air inlet section 111 in the valve body 1 is difficult to cause the return spring 22 to be compressed, resulting in the check valve being unable to open when the molecular pump and the vacuum pump are in the working state, and it is difficult to maintain the opening 121 in the open state. However, after the diaphragm assembly 3 is introduced, the diaphragm assembly 3 can choose to assist the gas in the air inlet section 111 in response to the pressure difference change between the outside and the inside of the valve body 1 (especially the air outlet section 112), so that the gas in the air inlet section 111 can overcome the resistance from the return spring 22 with the help of the diaphragm assembly 3, and push the valve core assembly 2 from the position of blocking the opening 121 to the position of opening the opening 121, thereby realizing the opening of the check valve.

[0036] Further, the partition structure 12 includes a partition body 122 and a bulge 123 disposed on the partition body 122 and extending toward the outlet 14, and the opening 121 is radially opened on the bulge 123. The valve core 21 includes a plug 211 for opening and blocking the opening 121, and a slide bar 212 which is slidably disposed in the valve body 1 along the radial direction of the valve body 1 and is fixedly connected to the plug 211. The return spring 22 is sleeved on the slide bar 212, and one end of the return spring 22 abuts against the inner wall of the valve body 1 and the other end of the return spring 22 abuts against the valve core 21. When the return spring 22 is compressed by the gas of the diaphragm assembly 3 and the air inlet section 111, it no longer presses the valve core 21, and the valve core 21 can move away from the bulge 123 along the radial direction of the valve body 1 under the action of the gas of the diaphragm assembly 3 and the air inlet section 111 to open the opening 121. When the return spring 22 is affected by the diaphragm assembly 3, its own elastic force and the gas in the outlet section 112, it recovers to the length when the opening 121 is blocked, so as to press the valve core 21 again, and the valve core 21 moves closer to the bulge 123 along the radial direction of the valve body 1 to block the opening 121. Among them, since the opening 121 and the slide rod 212 are both arranged along the radial direction of the valve body 1, the moving direction of the plug 211 is also passively restricted to the radial direction of the valve body 1, so that the movement of the valve core assembly 2 is to move along the radial direction of the valve body 1, thereby making the structure of the valve core assembly 2 more compact, and can reduce the influence of the gas flowing in the valve body 1 on the opening 121 when it needs to be opened or blocked, so that the valve core assembly 2 can respond more quickly and accurately to the pressure changes of the inlet section 111 and the outlet section 112.

[0037] Figure 4 The structure diagram of the valve core assembly 2 and the diaphragm assembly 3 provided in the present embodiment in the gas flow state is shown. Figure 5 FIG. 2 shows a schematic diagram of the structure of the valve core assembly 2 and the diaphragm assembly 3 provided in this embodiment in a blocked state. Figure 4 and Figure 5 Combined with Figure 1-Figure 3As shown, the valve body 1 includes a first radial hole 15 provided on the valve body 1 and connecting the air outlet section 112 of the inner cavity 11 with the outside, and the first radial hole 15 is arranged to face the bulge 123 of the partition structure 12 and face away from the opening 121. The diaphragm assembly 3 includes an elastic diaphragm 31 and a connecting member 32. The elastic diaphragm 31 is fixedly provided on the valve body 1 and blocks the first radial hole 15 of the valve body 1. The connecting member 32 is provided in the inner cavity 11 of the valve body 1, and includes a connecting membrane portion 321 connected to the diaphragm assembly 3, a connecting core portion 322 opposite to the connecting membrane portion 321 and connected to the valve core assembly 2, and a bending portion 323 connecting the connecting membrane portion 321 and the connecting core portion 322 and avoiding the bulge 123 of the partition structure 12. When the difference between the air pressure of the air inlet section 111 and the air pressure of the air outlet section 112 exceeds the set threshold, the elastic diaphragm 31, under the action of the atmospheric pressure, overcomes the resistance of the gas in the air outlet section 112 and deforms (from a flat state to a concave state), so as to help the gas in the air inlet section 111 overcome the resistance from the return spring 22 and the resistance from the gas in the air outlet section 112, and push the valve core assembly 2 from the position of blocking the opening 121 to the position of opening the opening 121. When the difference between the air pressure of the air inlet section 111 and the air pressure of the air outlet section 112 is equal to or lower than the set threshold, the air pressure of the air outlet section 112 increases, while the atmospheric pressure remains unchanged, causing the elastic diaphragm 31 to gradually change from a concave state to a flat state, so that the gas in the air outlet section 112 and the return spring 22 can jointly overcome the resistance of the gas in the air inlet section 111 and the resistance of the diaphragm assembly 3, and the valve core assembly 2 is pushed from the position of opening the opening 121 to the position of blocking the opening 121.

[0038] In this embodiment, the elastic diaphragm 31 is made of rubber material to ensure that the elastic diaphragm 31 can withstand certain pressure and deformation. In other embodiments, it can also be made of other materials that can achieve the above effects. This embodiment does not specifically limit this, and any elastic diaphragm 31 that can achieve the above effects should be within the protection scope of the disclosed embodiment.

[0039] Preferably, the valve core 21 further comprises a baffle 213 sleeved on the slide rod 212, and an adjusting nut 214 threadedly connected to the slide rod 212 and further away from the plug 211 than the baffle 213, and the return spring 22 and the connecting member 32 respectively abut against the two sides of the baffle 213, and force the baffle 213 to abut against the adjusting nut 214. When the valve core assembly 2 opens the opening 121, the baffle 213 moves under the action of the connecting member 32, and at the same time, the adjusting nut 214 moves and the slide rod 212 moves, so as to transmit the movement of the connecting member 32 to the valve core 21. Since the adjusting nut 214 is threadedly connected to the slide rod 212, when the application environment of the valve body 1 changes, the slide rod 212 can be adjusted to move along its own axial direction, so as to adjust the slide rod 212 to abut against the valve body 1 for a shorter time or a longer time, so as to adjust the valve core assembly 2 to open or block the opening 121 for a shorter time or a longer time.

[0040] Preferably, the core connecting portion 322 of the connecting member 32 is used to abut against the baffle 213 and has an opening for accommodating the connecting end of the plug 211, wherein the connecting end of the plug 211 refers to the end used to connect the slide rod 212, and the opening allows the connecting end of the plug 211 to pass through and connect together, so that the connecting end of the plug 211 directly abuts against the baffle 213, so as to save the space occupied by the connection position between the connecting member 32 and the valve core assembly 2 in the valve body 1, thereby making the overall structure of the valve body 1 more compact.

[0041] Figure 6 FIG. 2 shows a bottom view of the check valve provided in this embodiment. Figure 6 Combined with Figure 1-Figure 3 As shown, the first radial hole 15 is a first stepped hole with a first step, and the elastic diaphragm 31 is installed on the first step of the first stepped hole. The valve body 1 also includes a pressing block 16 installed in the first stepped hole and pressing the elastic diaphragm 31 on the first step. The pressing block 16 has a central through hole 161 and is fixed in the first stepped hole by a first fastening bolt 4 that penetrates itself and is screwed into the first step, so that the elastic diaphragm 31 is installed on the valve body 1 and remains firmly fixed. The elastic diaphragm 31 can also be detachably connected to the valve body 1 by fixing the elastic diaphragm 31 through the first fastening bolt 4 and the pressing block 16. The central through hole 161 ensures that the elastic diaphragm 31 can contact the outside air, so that deformation can be achieved by using the air pressure difference.

[0042] Figure 7 FIG. 4 shows a schematic structural diagram of the elastic diaphragm 31 provided in this embodiment. Figure 7 and Figure 6 Combined with Figure 1-Figure 3As shown, the elastic diaphragm 31 includes a diaphragm body 311 and a boss 312 arranged on the inner side of the diaphragm body 311 and having a limiting groove 313. The membrane connecting portion 321 of the connecting member 32 is inserted into the limiting groove 313 in a shape-matched manner. The limiting groove 313 can limit the movement of the connecting member 32, preventing the connecting member 32 from deviating from the original trajectory during the movement, thereby reducing the occurrence of the valve core assembly 2 failing to open smoothly.

[0043] Figure 8 FIG. 2 shows a top view of the check valve provided in this embodiment, Fig. 9 FIG. 1 shows a schematic diagram of the structure of the cover 18 provided in this embodiment. Figure 8 and Fig. 9 Combined with Figure 1-Figure 3 As shown, the valve body 1 includes a second radial hole 17 provided on the valve body 1 and symmetrical with the first radial hole 15, and a cover 18 that can be removably installed in the second radial hole 17, wherein the cover 18 has a positioning groove 181 for accommodating the slide rod 212 and allowing the slide rod 212 to slide along its depth direction, and an annular groove 182 for accommodating the return spring 22 and preventing the return spring 22 from generating string movement and / or sliding.

[0044] Furthermore, the second radial hole 17 is a second stepped hole with a second step, and the cover 18 is installed in the second stepped hole and abuts against the second step, and can be fixed in the second stepped hole by a second fastening bolt 5 that penetrates through the cover 18 and can be screwed into the second step, so as to achieve the installation of the valve core assembly 2 on the valve body 1 and keep it firmly fixed, and the valve core assembly 2 can also be detachably connected to the valve core assembly 2 through the cover 18 and the second fastening bolt 5, so that the user can adjust the slide rod 212 and the adjusting nut 214.

[0045] In the above description of the present application, unless otherwise clearly specified and limited, the terms "fixed", "installed", "connected" or "connected" and the like should be understood in a broad sense. For example, with regard to the term "connection", it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements. Therefore, unless otherwise clearly defined in the present application, those skilled in the art can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0046] According to the above description of the present application, those skilled in the art may also understand that the terms used below, such as "upper", "inner", "outer", "axial", "radial" and the like, indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings of the present application, and are only for the purpose of facilitating the explanation of the scheme of the present invention and simplifying the description, rather than explicitly or implicitly indicating that the device or element involved must have the specific orientation, be constructed and operated in a specific orientation. Therefore, the above-mentioned orientation or position relationship terms cannot be understood or interpreted as limitations on the scheme of the present invention.

[0047] In addition, the terms "first" or "second" used in this application to refer to numbers or ordinals are only used for descriptive purposes and cannot be understood as explicitly or implicitly indicating relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this application, the meaning of "plurality" is at least two, such as two, three or more, etc., unless otherwise clearly and specifically defined.

[0048] Although multiple embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Those skilled in the art may conceive of many changes, modifications, and alternatives without departing from the thought and spirit of the present invention. It should be understood that in the process of practicing the present invention, various alternatives to the embodiments of the present invention described herein may be adopted. The appended claims are intended to define the scope of protection of the present invention, and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. A check valve for negative pressure environment, characterized in that: The check valve comprises: A valve body, comprising an inner cavity, a partition structure fixedly arranged in the inner cavity and dividing the inner cavity into an air inlet section and an air outlet section, an inlet connected to the air inlet section of the inner cavity, and an outlet connected to the air outlet section of the inner cavity, wherein the partition structure has an opening for connecting the air inlet section and the air outlet section; A valve core assembly, comprising a valve core disposed in the inner cavity and used to open or block the opening, and a return spring disposed in the valve body and abutting or connected to the valve core; and A diaphragm assembly, which is partially exposed and disposed on the valve body and can increase the force acting on the valve core assembly according to the increase of the pressure difference between the inside and outside of the valve body; When the difference between the air pressure of the air inlet section and the air pressure of the air outlet section exceeds a set threshold, the gas entering the air inlet section can, with the help of the diaphragm assembly, overcome the resistance from the return spring and the resistance from the gas in the air outlet section, and push the valve core assembly to move from a position blocking the opening to a position opening the opening; When the difference between the air pressure in the air inlet section and the air pressure in the air outlet section is equal to or lower than the set threshold value, the return spring can, with the help of the gas entering the air outlet section, overcome the resistance from the diaphragm assembly and the resistance from the gas in the air inlet section and push the valve core assembly to return from the position of opening the opening to the position of blocking the opening.

2. The check valve according to claim 1, characterized in that: The partition structure comprises a partition body and a bulge portion provided on the partition body and extending toward the outlet, and the opening is radially opened on the bulge portion; The valve core includes a plug for opening and closing the opening, and a slide rod which is slidably disposed in the valve body along the radial direction of the valve body and is fixedly connected to the plug; and The return spring is sleeved on the slide rod, with one end abutting against the inner wall of the valve body and the other end abutting against the valve core.

3. The check valve according to claim 2, characterized in that: The valve body includes a first radial hole disposed thereon and connecting the air outlet section of the inner cavity with the outside, wherein the first radial hole is disposed toward the bulging portion of the partition structure and facing away from the opening; The diaphragm assembly comprises: an elastic diaphragm fixedly mounted on the valve body and blocking the first radial hole of the valve body; and a connecting member disposed in the inner cavity of the valve body and comprising a film connecting portion connected to the diaphragm assembly, a core connecting portion opposite to the film connecting portion and connected to the valve core assembly, and a curved portion connecting the film connecting portion and the core connecting portion and avoiding the bulging portion of the partition structure; Among them, when the difference between the air pressure in the air inlet section and the air pressure in the air outlet section exceeds a set threshold, the elastic diaphragm overcomes the resistance of the gas in the air inlet section and deforms under the action of atmospheric pressure, and transmits its own force to the valve core assembly through the connecting member, so as to help the gas entering the air inlet section push the valve core assembly from a position blocking the opening to a position opening the opening.

4. The check valve according to claim 3, characterized in that: The valve core also includes a baffle plate which is sleeved on the sliding rod and abuts against the plug, and an adjusting nut which is threadedly connected to the sliding rod and is farther away from the plug than the baffle plate. The return spring and the connecting member respectively abut against two sides of the baffle plate, and the connection between the sliding rod and the plug is a threaded connection.

5. The check valve according to claim 4, characterized in that: The core-connecting portion of the connecting member is used to abut against the blocking piece and has an opening for accommodating the connecting end of the plug, wherein the connecting end of the plug refers to the end portion used to connect with the sliding rod.

6. The check valve according to claim 3, characterized in that: The first radial hole is a first stepped hole having a first step, the elastic diaphragm is installed on the first step of the first stepped hole, the valve body also includes a pressing block which is installed in the first stepped hole and presses the elastic diaphragm on the first step, the pressing block has a central through hole, and is fixed in the first stepped hole by a first fastening bolt which penetrates the pressing block and is screwed into the first step.

7. The check valve according to claim 3, characterized in that: The valve body includes a second radial hole arranged thereon and symmetrical to the first radial hole, and a cover that can be detachably installed in the second radial hole, wherein the cover has a positioning groove for accommodating the sliding rod and allowing the sliding rod to slide along its depth direction, and an annular groove for accommodating the return spring and preventing the return spring from stringing and / or sliding.

8. The check valve according to claim 7, characterized in that: The second radial hole is a second stepped hole with a second step. The cover is installed in the second stepped hole and abuts against the second step, and can be fixed in the second stepped hole by a second fastening bolt that penetrates the cover and can be screwed into the second step.

9. The check valve according to claim 3, characterized in that: The elastic diaphragm comprises a diaphragm body and a boss which is arranged on the inner side of the diaphragm body and has a limiting groove, and the membrane connecting portion of the connecting member is inserted into the limiting groove in a shape-matched manner.

10. A vacuum creation system, characterized in that: A molecular pump, a check valve connected to the molecular pump, and a vacuum pump connected to the check valve are sequentially arranged along the gas flow direction, and the check valve is the check valve as described in any one of claims 1 to 9.

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