An overpressure protection device for vacuum gauge

Abstract

The present invention discloses an overpressure protection device for a vacuum gauge, which relates to the technical field of overpressure protection of vacuum gauges, and comprises a main pipe and a control module, wherein a cover is fixedly connected to the right side of the main pipe, and three openings are opened on the right side of the cover, and a first fixed pipe is fixedly connected to the inner wall of the upper opening on the right side of the cover, and an exhaust port is opened on the upper middle side of the first fixed pipe, and a pressure valve is fixedly connected to the inner wall of the first fixed pipe, and a sealing mechanism and a pressure reducing mechanism are respectively provided inside the two openings on the lower right side of the cover. The present invention can realize real-time sensing and active sealing control of abnormal pressure caused by recoil airflow, and by providing a second fixed pipe, a telescopic rod and an elastic rod, it can synchronize and amplify the transmission force to the pressure rod through mechanical displacement conversion when the air pressure rises, thereby enhancing the sensing accuracy and response sensitivity of the piezoelectric module, and has the characteristics of strong practicality and effective improvement of the reliability of the vacuum gauge.

Description

Technical Field

[0001] The present invention relates to the technical field of vacuum gauge overpressure protection, in particular to an overpressure protection device for a vacuum gauge. Background Art

[0002] As a key component in a vacuum system used to monitor pressure changes within a cavity, the vacuum gauge's measurement accuracy and service life depend largely on the stability of the pressure environment. However, in practical applications, when the vacuum system is connected to the cavity to be measured, backflow or transient overpressure can often occur due to factors such as sudden gas release, misoperation, or seal failure. Such phenomena can cause airflow to flow back into the vacuum gauge, disrupting its normal measurement accuracy and potentially damaging the sensor structure. In severe cases, this can even lead to the failure of the entire vacuum system.

[0003] Existing Chinese patent publication number: CN109060238A discloses a vacuum gauge overpressure protection device. The device begins to relieve pressure when the pressure exceeds 0.16 bar. When encountering a pressure shock, the vacuum gauge channel is quickly blocked and the overpressure relief channel is simultaneously relieved to protect the safety of the vacuum gauge. The device is designed to use the air pressure to break through a certain threshold. The air pressure is used to lift the second sphere through the air pressure thrust, the second sphere is separated from the fixed lower ball seat, and the gas passes through the second air channel, and the overpressure relief channel is relieved. When the pressure of the floating lower ball seat and the first ball exceeds 0.12 bar, the vacuum gauge channel is closed. During this process, the recoil speed and recoil amount of the recoil airflow are not accurately limited. Therefore, the recoil of the airflow that does not reach the pressure threshold in a short time may still damage the vacuum gauge.

[0004] In addition, the device has difficulty in quickly guiding and balancing the residual gas pressure after a recoil occurs, which can easily cause the vacuum gauge area to remain in a high-pressure state, further increasing the risk of damage.

[0005] Therefore, it is urgent to propose an overpressure protection device for vacuum gauges with fast response speed, high recognition accuracy, dual protection and pressure relief capabilities. The device can not only actively identify the increase in the recoil airflow speed in a short period of time and initiate a protection response in real time, but also regulate the system pressure while closing the passage, thereby effectively improving the reliability of the vacuum gauge and the safety of the system. Summary of the Invention

[0006] The object of the present invention is to provide an overpressure protection device for a vacuum gauge to solve the problems raised in the above background technology.

[0007] In order to solve the above technical problems, the present invention provides the following technical solution: an overpressure protection device for a vacuum gauge, comprising a main pipe and a control module, characterized in that: a cover is fixedly connected to the right side of the main pipe, three openings are opened on the right side of the cover, a first fixed pipe is fixedly connected to the inner wall of the upper opening on the right side of the cover, an exhaust port is opened on the upper middle side of the first fixed pipe, a pressure valve is fixedly connected to the inner wall of the first fixed pipe, and a sealing mechanism and a pressure reducing mechanism are respectively provided inside the two openings on the lower right side of the cover;

[0008] The sealing mechanism includes a connecting assembly, a pressure rod, and a piezoelectric module. One end of the pressure rod contacts the outer wall of the piezoelectric module, and the pressure rod can change the pressure on the piezoelectric module according to the change of the internal air pressure of the main pipe.

[0009] The sealing mechanism further comprises a sealing ring and a sealing sheet on the upper side of the sealing ring, wherein the sealing sheet can be lowered to seal the sealing ring;

[0010] The pressure reducing mechanism includes a third fixed pipe, a fixed assembly, and a sealing block that can move relative to the fixed assembly. The sealing block can isolate the third fixed pipe and the interior of the main pipe into two sealed cavities.

[0011] The lockhole that is formed on the upper end of the hinge part is formed on the upper end of the crankcase, and the hinge part has an inner wall of the lockhole that is formed on the upper end of the hinge part.

[0012] According to the above technical solution, the outer wall of the sealing ring is fixedly connected to the upper inner wall of the main pipe, the inner wall of the sealing ring is fixedly connected to an electromagnet, the lower side of the sealing ring is fixedly connected to a support frame, the upper surface of the support frame is fixedly connected to a spring, the upper end of the spring is fixedly connected to the lower surface of the sealing sheet, the lower end of the sealing sheet is also fixedly connected to a second sliding rod, the lower end of the second sliding rod passes through the support frame and extends to the lower side of the support frame, the outer wall of the second sliding rod contacts the inner wall of the support frame, the upper surface of the sealing sheet is fixedly connected to a metal sheet, the outer wall of the main pipe is fixedly connected to the first motor, the output end of the first motor is fixedly connected to a rotating rod, one end of the rotating rod passes through the main pipe and extends to the interior of the main pipe, and the rotating rod is located on the outer wall of the inner side of the main pipe and is fixedly connected to a pressure block.

[0013] According to the above technical solution, the outer diameter of the sealing sheet is larger than the inner diameter of the sealing ring, the sealing sheet and the sealing ring are both made of rubber, the metal sheet is made of metal, and the pressure block is located on the upper side of the metal sheet. The pressure block is a horizontal triangular structure, and the left-right length of the pressure block is greater than the distance between the outer wall of the rotating rod and the upper surface of the metal sheet.

[0014] According to the above technical solution, the elastic rod is made of elastic metal material, the telescopic rod can change its length, the elastic metal film is made of elastic metal material, the piezoelectric module is electrically connected to the control module, and the first motor and electromagnet are both electrically connected to the control module.

[0015] According to the above technical solution, the connection point between the fixing frame and the telescopic rod is located at the lower middle part of the telescopic rod, and when the elastic metal film is not deformed, the torsion spring at the connection between the fixing frame and the telescopic rod can make the pressure rod contact with the piezoelectric module.

[0016] According to the above technical solution, the left end of the third fixed tube is fixedly connected to the inner wall of the upper opening of the cover, the left side of the inner wall of the third fixed tube is fixedly connected with a retaining ring, the right side of the inner wall of the third fixed tube is fixedly connected with an elastic membrane, an extension rod is provided inside the third fixed tube, the right end of the extension rod passes through the elastic membrane and extends to the right side of the elastic membrane, the left end of the extension rod is fixedly connected to the right side of the sealing block, the right side of the extension rod is fixedly connected to a threaded barrel, the right side of the outer wall of the third fixed tube is fixedly connected to a fixed frame, the inner wall of the fixed frame is fixedly connected to a second motor, the output end of the second motor is fixedly connected to a threaded rod, the outer wall of the threaded rod is threadedly connected to the inner wall of the threaded barrel, and the left end of the third fixed tube is fixedly connected to the inner wall of the upper opening of the cover.

[0017] According to the above technical solution, the elastic membrane is an elastic diaphragm structure, the outer diameter of the sealing block is larger than the inner diameter of the retaining ring, the second motor is connected to the control module, and when the sealing block is not in contact with the retaining ring, the interior of the third fixed tube is connected to the interior of the main tube.

[0018] Compared with the prior art, the present invention has the following beneficial effects: the present invention, by providing the pressure rod, piezoelectric module, sealing ring, and sealing sheet in the sealing mechanism, can realize real-time sensing and active sealing control of abnormal pressure caused by recoil airflow; by providing the second fixed tube, telescopic rod, and elastic rod, when the air pressure rises, the force transmitted to the pressure rod can be synchronously and amplified through mechanical displacement conversion, thereby enhancing the sensing accuracy and response sensitivity of the piezoelectric module, thereby realizing rapid recognition of recoil events and linking the sealing structure to prevent airflow from entering the vacuum gauge and causing damage;

[0019] By setting up an electromagnet and a metal sheet, and cooperating with a sealing sheet and a sealing ring, the upward airflow can be quickly blocked at the initial stage of recoil. When the control module detects a sudden voltage change, the electromagnet magnetically attracts the metal sheet to complete the blockage, effectively cutting off the airflow path.

[0020] By providing a first motor, a rotating rod, and a pressing block, and electrically connecting them to the control module, an auxiliary reinforcement mechanism after sealing is realized. After the initial magnetic sealing, the first motor drives the pressing block to press the upper surface of the metal sheet, using mechanical pressure instead of electromagnetic adsorption to enhance the sealing. This not only reduces the risk of heating caused by continuous power supply to the electromagnet and avoids affecting the stability of the vacuum gauge's measurement environment, but also improves the continuous reliability of the metal sheet sealing effect, ensuring the sealing integrity in the face of multiple or high-intensity recoils.

[0021] By providing a pressure-reducing mechanism, including an extension rod, an elastic membrane, a sealing block and a threaded rod, the air pressure in the third fixed tube cavity is actively adjusted when it is detected that the air pressure reaches a threshold value, so as to achieve slow-release control of the air pressure change inside the main tube. When recoil occurs, the structure delays the connection and extracts the high-pressure gas in the main tube cavity, reduces its rising speed, and induces the metal sheet to close quickly through gas backflow, reducing the duration and intensity of high pressure, further improving the protection effect of the vacuum gauge, and significantly reducing errors and device damage caused by pressure fluctuations. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0023] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0024] Figure 2 It is a schematic diagram of the rear structure of the present invention;

[0025] Figure 3 It is a schematic diagram of the split structure of the present invention;

[0026] Figure 4 Schematic diagram of the internal structure of the sealing ring of the present invention;

[0027] Figure 5 It is a partial structural diagram of the sealing mechanism of the present invention;

[0028] Figure 6 This is a schematic diagram of the internal structure of the second fixed tube of the present invention;

[0029] Figure 7 It is a schematic structural diagram of the pressure reducing mechanism of the present invention;

[0030] Figure 8 1 is a schematic cross-sectional structural diagram of the pressure reducing mechanism of the present invention;

[0031] Figure: 1, main pipe; 2, cover; 3, first fixed pipe; 4, exhaust port; 5, pressure valve; 6, closing mechanism; 7, pressure reducing mechanism; 601, second fixed pipe; 602, slide; 603, elastic metal film; 604, first slide; 605, ball bearing; 606, telescopic rod; 607, elastic rod; 608, pressure rod; 609, fixed frame; 610, connecting frame; 611, fixed box; 612, piezoelectric module; 613 , sealing ring; 614, electromagnet; 615, support frame; 616, spring; 617, sealing sheet; 618, second slide rod; 619, metal sheet; 620, first motor; 621, rotating rod; 622, pressure block; 701, third fixed tube; 702, elastic membrane; 703, extension rod; 704, sealing block; 705, threaded cylinder; 706, fixed frame; 707, second motor; 708, threaded rod; 709, retaining ring. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] See also Figure 1-8 The present invention provides a technical solution: an overpressure protection device for a vacuum gauge, comprising a main pipe 1 and a control module, a cover 2 fixedly connected to the right side of the main pipe 1, three openings being opened on the right side of the cover 2, a first fixed pipe 3 fixedly connected to the inner wall of the upper opening on the right side of the cover 2, an exhaust port 4 being opened on the upper middle side of the first fixed pipe 3, a pressure valve 5 fixedly connected to the inner wall of the first fixed pipe 3, and a sealing mechanism 6 and a pressure reducing mechanism 7 being respectively provided inside the two openings on the lower right side of the cover 2;

[0034] During the actual application of this device, the lower side of the main pipe 1 is connected to the measured cavity, and then the upper side of the main pipe 1 is connected to the vacuum gauge. The air flow moves through the inside of the main pipe 1. When the air flow backflow occurs, the air pressure inside the main pipe 1 can be released through the pressure valve 5.

[0035] The closing mechanism 6 includes a connecting assembly, a pressure rod 608, and a piezoelectric module 612. One end of the pressure rod 608 contacts the outer wall of the piezoelectric module 612. The pressure rod 608 can change the pressure on the piezoelectric module 612 according to the change of the internal air pressure of the main pipe 1. The closing mechanism 6 also includes a sealing ring 613 and a sealing sheet 617 on the upper side of the sealing ring 613. The sealing sheet 617 can be lowered to seal the sealing ring 613. The connecting assembly includes a second fixed tube 601. The left end of the second fixed tube 601 is fixedly connected to the inner wall of the opening on the cover 2. The inner wall of the second fixed tube 601 is fixedly connected to the slide 602. The inner wall of the slide 602 is on the left. The side is fixedly connected with an elastic metal film 603, and the middle part of the inner wall of the slide 602 is slidably connected with a first slide bar 604. The left end of the first slide bar 604 is embedded with a ball 605. The outer wall of the ball 605 contacts the outer wall of the elastic metal film 603. The right end of the first slide bar 604 is hinged with a telescopic rod 606. The lower end of the telescopic rod 606 is plugged with an elastic rod 607. The outer wall of the telescopic rod 606 is hinged with a fixed frame 609 through a torsion spring. The upper end of the fixed frame 609 is fixedly connected to the outer wall of the cover 2, and the lower end of the elastic rod 607 intersects with the right end of the pressure rod 608. The connecting component also includes a connecting frame 610. The upper end is fixedly connected to the outer wall of the cover 2, the lower end of the connecting frame 610 is fixedly connected to a fixed box 611, the right inner wall of the fixed box 611 is slidably connected to the outer wall of the pressure rod 608, the left inner wall of the fixed box 611 is fixedly connected to the outer wall of the piezoelectric module 612, the outer wall of the sealing ring 613 is fixedly connected to the upper inner wall of the main pipe 1, the inner wall of the sealing ring 613 is fixedly connected to the electromagnet 614, the lower side of the sealing ring 613 is fixedly connected to a support frame 615, the upper surface of the support frame 615 is fixedly connected to a spring 616, the upper end of the spring 616 is fixedly connected to the lower surface of the sealing sheet 617, and the lower end of the sealing sheet 617 is also fixedly connected to the upper inner wall of the main pipe 1. A second slide bar 618 is fixedly connected, and the lower end of the second slide bar 618 passes through the support frame 615 and extends to the lower side of the support frame 615. The outer wall of the second slide bar 618 contacts the inner wall of the support frame 615. The outer diameter of the sealing sheet 617 is larger than the inner diameter of the sealing ring 613. The sealing sheet 617 and the sealing ring 613 are both made of rubber. The elastic rod 607 is made of elastic metal. The telescopic rod 606 can be changed in length. The elastic metal film 603 is made of elastic metal. The piezoelectric module 612 is electrically connected to the control module. The upper surface of the sealing sheet 617 is fixedly connected to a metal sheet 619, and the metal sheet 619 is made of metal.

[0036] During use, if airflow backflow occurs, first, the airflow flows back from the lower side of the main pipe 1 to the inside of the main pipe 1, and the sealing ring 613 and the sealing sheet 617 can create resistance to the upward flow of the airflow, which will increase the pressure inside the main pipe 1. The increased pressure inside the main pipe 1 will cause the sealing ring 613 to expand and deform outward, thereby applying a rightward force to the ball 605 and the first sliding rod 604. The rightward movement of the right end of the first sliding rod 604 will drive the telescopic rod 606 to deflect, thereby causing the lower side of the telescopic rod 606 to apply a leftward force to the elastic rod 607, which pushes the pressure rod 608 through the lower end of the elastic rod 607 to apply pressure to the piezoelectric module 612;

[0037] When the pressure rod 608 applies pressure to the piezoelectric module 612, the output voltage of the piezoelectric module 612 fluctuates. The control module detects the output voltage fluctuation of the piezoelectric module 612. The control module collects the voltage value of the piezoelectric module 612 in real time and analyzes the voltage change rate per unit time to determine whether it meets the following conditions:

[0038]

[0039] in, Indicates the voltage value at the current sampling moment, Indicates the voltage value at the last sampling moment, is the sampling interval, is a preset voltage change rate threshold;

[0040] When this condition is met, it means that the output voltage of the piezoelectric module 612 increases beyond the threshold value per unit time. At this time, the control module activates the electromagnet 614, causing the electromagnet 614 to attract the metal sheet 619, thereby causing the sealing sheet 617 to seal the sealing ring 613. The recoil airflow is blocked by the sealing ring 613 and the sealing sheet 617, preventing the inside of the vacuum gauge from being damaged by the impact of the recoil airflow.

[0041] The outer wall of the main pipe 1 is fixedly connected to a first motor 620, and the output end of the first motor 620 is fixedly connected to a rotating rod 621. One end of the rotating rod 621 passes through the main pipe 1 and extends to the interior of the main pipe 1. The rotating rod 621 is located on one side of the inner outer wall of the main pipe 1 and is fixedly connected to a pressure block 622. The pressure block 622 is located on the upper side of the metal sheet 619. The pressure block 622 is a horizontal triangular structure, and the left-right length of the pressure block 622 is greater than the distance between the outer wall of the rotating rod 621 and the upper surface of the metal sheet 619. The first motor 620 and the electromagnet 614 are both electrically connected to the control module. The connection point between the fixed frame 609 and the telescopic rod 606 is located on the lower side of the middle part of the telescopic rod 606. When the elastic metal film 603 is in the undeformed state, the torsion spring at the connection between the fixed frame 609 and the telescopic rod 606 can make the pressure rod 608 contact with the piezoelectric module 612.

[0042] After the control module detects that the output voltage of the piezoelectric module 612 exceeds the threshold value per unit time, the first motor 620 is started at the same time to drive the rotating rod 621 and the pressure block 622 to deflect. At this time, since the response speed of the electromagnet 614 is faster than that of the metal sheet 619, the metal sheet 619 has moved downward at this time, and the pressure block 622 and the rotating rod 621 do not contact the metal sheet 619 in the initial rotation. Therefore, the starting load of the first motor 620 is relatively low, so that the first motor 620 can drive the pressure block 622 to deflect and press the metal sheet 619 more quickly. After the control module drives the pressure block 622 to deflect and contact the metal sheet 619 through the first motor 620, the electromagnet 614 is turned off, which can reduce the temperature increase of the main pipe 1 and the internal temperature of the vacuum gauge caused by the working temperature increase of the electromagnet 614. At the same time, the pressure block 622 squeezes the upper side of the metal sheet 619, so that the metal sheet 619 can withstand a larger air pressure in the subsequent airflow recoil, thereby avoiding sealing failure caused by the increase of the recoil airflow.

[0043] The pressure reducing mechanism 7 includes a third fixed tube 701, a fixed assembly and a sealing block 704 that can move relative to the fixed assembly. The sealing block 704 can isolate the third fixed tube 701 from the inside of the main tube 1 into two sealed cavities. The left end of the third fixed tube 701 is fixedly connected to the inner wall of the opening on the sealing cover 2. A retaining ring 709 is fixedly connected to the left side of the inner wall of the third fixed tube 701. An elastic membrane 702 is fixedly connected to the right side of the inner wall of the third fixed tube 701. An extension rod 703 is provided inside the third fixed tube 701. The right end of the extension rod 703 passes through the elastic membrane 702 and extends to the right side of the elastic membrane 702. The left end of the extension rod 703 is fixedly connected to the right side of the sealing block 704. A threaded barrel 705 is fixedly connected to the right side, a fixed frame 706 is fixedly connected to the right side of the outer wall of the third fixed tube 701, a second motor 707 is fixedly connected to the inner wall of the fixed frame 706, a threaded rod 708 is fixedly connected to the output end of the second motor 707, the outer wall of the threaded rod 708 is threadedly connected to the inner wall of the threaded barrel 705, the left end of the third fixed tube 701 is fixedly connected to the inner wall of the opening on the cover 2, the elastic membrane 702 is a diaphragm structure with elasticity, the outer diameter of the sealing block 704 is larger than the inner diameter of the retaining ring 709, the second motor 707 is connected to the control module, and when the sealing block 704 is not in contact with the retaining ring 709, the interior of the third fixed tube 701 is connected to the interior of the main pipe 1;

[0044] During the application of the device, the control module is electrically connected to the vacuum gauge. When the air pressure inside the main pipe 1 gradually decreases, every time it drops a preset gradient, the control module drives the threaded rod 708 to rotate through the second motor 707, and the threaded rod 708 drives the threaded cylinder 705, the extension rod 703, and the sealing block 704 to move to the right, so that the interior of the third fixed pipe 701 is connected to the interior of the main pipe 1 to restore the air pressure balance. Then, the threaded rod 708 is driven to reverse by the second motor 707, so that the sealing block 704 seals the retaining ring 709. When the air pressure drops to another gradient, the above process is repeated, so that the air pressure drop speed inside the third fixed pipe 701 lags behind the air pressure drop speed inside the main pipe 1. When airflow backflow occurs inside, the air pressure inside the main pipe 1 rises rapidly, and the sealing mechanism 6 seals the upper side of the main pipe 1. At the same time, the second motor 707 is started to drive the threaded rod 708 to rotate, causing the threaded cylinder 705, the sealing block 704, and the extension rod 703 to move rightward, thereby connecting the interior of the third fixed pipe 701 with the interior of the main pipe 1. At this time, the air pressure inside the third fixed pipe 701 is lower than the air pressure inside the main pipe 1, and the rightward movement of the extension rod 703 drives the elastic membrane 702 to deform rightward, causing the third fixed pipe 701 to extract the air from the main pipe 1, thereby slowing down the rate of increase in the air pressure inside the main pipe 1, reducing the amount of gas escaping from the main pipe 1 to the vacuum gauge, and reducing the risk of damage to the vacuum gauge.

[0045] At the same time, when the elastic membrane 702 is deformed to the right by the extension rod 703, the gas inside the main pipe 1 will be quickly extracted into the third fixed pipe 701, and the recoil airflow will be balanced in a short time. Then, the escaped airflow on the upper side of the main pipe 1 is in the high-pressure area, and the upper airflow will be drawn back downward, so that the airflow drives the metal sheet 619 to descend and seal faster, while reducing the possibility of continued high pressure in the vacuum gauge area and the probability of damage.

[0046] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0047] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An overpressure protection device for a vacuum gauge, comprising a main pipe (1) and a control module, characterized in that: The right side of the main pipe (1) is fixedly connected to a cover (2), and three openings are provided on the right side of the cover (2). A first fixed pipe (3) is fixedly connected to the inner wall of the upper opening on the right side of the cover (2), and an exhaust port (4) is provided on the upper middle side of the first fixed pipe (3). A pressure valve (5) is fixedly connected to the inner wall of the first fixed pipe (3), and a closing mechanism (6) and a pressure reducing mechanism (7) are respectively provided inside the two openings on the lower right side of the cover (2); The sealing mechanism (6) includes a connecting assembly, a pressure rod (608), and a piezoelectric module (612). One end of the pressure rod (608) contacts the outer wall of the piezoelectric module (612). The pressure rod (608) can change the pressure on the piezoelectric module (612) according to the change of the internal air pressure of the main pipe (1). The piezoelectric module (612) is electrically connected to a control module. The control module is used to detect the voltage change rate of the piezoelectric module (612) in real time and output a control signal when the voltage change rate exceeds a preset threshold value. The sealing mechanism (6) further comprises a sealing ring (613), a sealing sheet (617) on the upper side of the sealing ring (613), an electromagnet (614) inside the sealing ring (613), and a first motor (620); the sealing sheet (617) can be lowered to seal the sealing ring (613); the electromagnet (614) and the first motor (620) are both electrically connected to the control module, and drive the sealing sheet (617) to lower and seal the sealing ring (613) when the control module receives the control signal; The pressure reducing mechanism (7) comprises a third fixed tube (701), a fixed assembly, and a sealing block (704) movable relative to the fixed assembly. The sealing block (704) can isolate the third fixed tube (701) from the interior of the main tube (1) into two sealed cavities. The sealing block (704) is connected to the second motor (707) via a threaded rod (708) and an extension rod (703). The second motor (707) is electrically connected to a control module. The control module is used to drive the second motor (707) to move the sealing block (704) to connect or isolate the third fixed tube (701) from the interior of the main tube (1) when it is detected that the air pressure inside the main tube (1) reaches a preset threshold, thereby adjusting the air pressure inside the third fixed tube (701) and realizing slow-release control of the air pressure change inside the main tube (1).

2. The overpressure protection device for a vacuum gauge according to claim 1, characterized in that: The connecting assembly includes a second fixed tube (601), the left end of the second fixed tube (601) is fixedly connected to the inner wall of the opening on the cover (2), the inner wall of the second fixed tube (601) is fixedly connected to a slide (602), the left side of the inner wall of the slide (602) is fixedly connected to an elastic metal film (603), the middle part of the inner wall of the slide (602) is slidably connected to a first slide bar (604), the left end of the first slide bar (604) is embedded with a ball (605), the outer wall of the ball (605) is in contact with the outer wall of the elastic metal film (603), the right end of the first slide bar (604) is hinged to a telescopic rod (606), the lower end of the telescopic rod (606) is hinged to the left end of the telescopic rod (606). The end of the telescopic rod (606) is connected with an elastic rod (607), the outer wall of the telescopic rod (606) is hinged with a fixing frame (609) through a torsion spring, the upper end of the fixing frame (609) is fixedly connected to the outer wall of the cover (2), the lower end of the elastic rod (607) is connected to the right end of the pressure rod (608), and the connecting assembly also includes a connecting frame (610), the upper end of the connecting frame (610) is fixedly connected to the outer wall of the cover (2), and the lower end of the connecting frame (610) is fixedly connected to a fixing box (611), the right inner wall of the fixing box (611) is slidably connected to the outer wall of the pressure rod (608), and the left inner wall of the fixing box (611) is fixedly connected to the outer wall of the piezoelectric module (612).

3. The overpressure protection device for a vacuum gauge according to claim 2, characterized in that: The outer wall of the sealing ring (613) is fixedly connected to the upper inner wall of the main pipe (1), the outer wall of the electromagnet (614) is fixedly connected to the inner wall of the sealing ring (613), the lower side of the sealing ring (613) is fixedly connected to a support frame (615), the upper surface of the support frame (615) is fixedly connected to a spring (616), the upper end of the spring (616) is fixedly connected to the lower surface of the sealing sheet (617), the lower end of the sealing sheet (617) is also fixedly connected to a second slide bar (618), the lower end of the second slide bar (618) passes through the support frame ( 615) extends to the lower side of the support frame (615), the outer wall of the second slide bar (618) contacts the inner wall of the support frame (615), the upper surface of the sealing sheet (617) is fixedly connected with a metal sheet (619), the outer wall of the first motor (620) is fixedly connected to the outer wall of the main pipe (1), the output end of the first motor (620) is fixedly connected with a rotating rod (621), one end of the rotating rod (621) passes through the main pipe (1) and extends to the inside of the main pipe (1), and the rotating rod (621) is located on the outer wall of one side of the inside of the main pipe (1) and is fixedly connected with a pressure block (622).

4. The overpressure protection device for a vacuum gauge according to claim 3, characterized in that: The outer diameter of the sealing sheet (617) is greater than the inner diameter of the sealing ring (613); the sealing sheet (617) and the sealing ring (613) are both made of rubber; the metal sheet (619) is made of metal; and the pressing block (622) is located on the upper side of the metal sheet (619); the pressing block (622) is a horizontal triangular structure; and the left-right length of the pressing block (622) is greater than the distance between the outer wall of the rotating rod (621) and the upper surface of the metal sheet (619).

5. The overpressure protection device for a vacuum gauge according to claim 4, characterized in that: The elastic rod (607) is made of a metal material with elasticity, the telescopic rod (606) can change in length, the elastic metal film (603) is made of a metal material with elasticity, the piezoelectric module (612) is electrically connected to the control module, and the first motor (620) and the electromagnet (614) are both electrically connected to the control module.

6. The overpressure protection device for a vacuum gauge according to claim 5, characterized in that: The connection point between the fixed frame (609) and the telescopic rod (606) is located at the lower middle side of the telescopic rod (606), and when the elastic metal film (603) is in an undeformed state, the torsion spring at the connection between the fixed frame (609) and the telescopic rod (606) can make the pressure rod (608) contact with the piezoelectric module (612).

7. The overpressure protection device for a vacuum gauge according to claim 6, characterized in that: The left end of the third fixed tube (701) is fixedly connected to the inner wall of the upper opening of the cover (2), a retaining ring (709) is fixedly connected to the left side of the inner wall of the third fixed tube (701), and an elastic membrane (702) is fixedly connected to the right side of the inner wall of the third fixed tube (701). The extension rod (703) is arranged inside the third fixed tube (701), and the right end of the extension rod (703) passes through the elastic membrane (702) and extends to the right side of the elastic membrane (702). The left end of the extension rod (703) is fixedly connected to the right side of the sealing block (704). The right side of the extension rod (703) is fixedly connected to a threaded barrel (705), the right side of the outer wall of the third fixed tube (701) is fixedly connected to a fixed frame (706), the outer wall of the second motor (707) is fixedly connected to the inner wall of the fixed frame (706), the output end of the second motor (707) is fixedly connected to one end of the threaded rod (708), the outer wall of the threaded rod (708) is threadedly connected to the inner wall of the threaded barrel (705), and the left end of the third fixed tube (701) is fixedly connected to the inner wall of the upper opening of the cover (2).

8. The overpressure protection device for a vacuum gauge according to claim 7, characterized in that: The elastic membrane (702) is a diaphragm structure with elasticity. The outer diameter of the sealing block (704) is larger than the inner diameter of the retaining ring (709). The second motor (707) is connected to the control module. When the sealing block (704) is not in contact with the retaining ring (709), the interior of the third fixed pipe (701) is connected to the interior of the main pipe (1).

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