Pressure instrument with self protection

Abstract

A self-protective pressure instrument disclosed by the present invention comprises an instrument body, the instrument body is internally provided with a pointer and a transmission mechanism, the instrument body is fixedly provided with a mounting part, the mounting part is internally provided with a transmission rod and a pressure conversion piece, and the mounting part is communicated with the interior of the instrument body. The pressure conversion piece comprises a first component and a second component which are located in the mounting part, the second component is in sliding sealing connection with the mounting part in the length direction of the mounting part, a third component is arranged between the first component and the second component, and the third component and the second component are connected through a first elastic piece; a connecting rod is fixed to the side, back to the second component, of the third component, the end, away from the third component, of the connecting rod is connected with the transmission rod, and a first limiting part and a second limiting part are arranged between the first component and the second component. The invention aims to solve the technical problems of material fatigue caused by excessive deformation of an elastic element, abrasion of a gear tooth surface and deformation and bending of a connecting rod caused by transmission of overload pressure to a transmission mechanism.

Description

Technical Field

[0001] The present invention belongs to the technical field of pressure measurement, and more specifically, relates to a pressure instrument with self-protection. Background Art

[0002] Traditional mechanical pressure instruments are widely used in fields such as the automotive industry, chemical production, and medical treatment. Taking the automotive industry as an example, although modern automobile manufacturing highly relies on automated detection equipment, mechanical pressure gauges are still important auxiliary tools for manual spot checks due to their characteristics of not requiring an external power source and having a rapid response. For example, after the completion of automobile assembly, the air conditioning system needs to undergo a leak test and pressure detection, and at this time, the mechanical pressure gauge can efficiently intervene in the detection process.

[0003] The mainstream mechanical pressure gauges are divided into three structures: bourdon tube type, diaphragm type, and bellows type. When the measured pressure exceeds the design range of the instrument, the elastic element (bourdon tube / diaphragm / bellows) will cause material fatigue due to excessive deformation. In the light case, irreversible plastic deformation will occur, and in the severe case, rupture will occur. At the same time, the overload pressure will be transmitted to the transmission mechanism, resulting in wear of the gear tooth surface and deformation and bending of the connecting rod. In the light case, the pointer will get stuck, and in the severe case, the transmission chain will break, ultimately resulting in deviation of the instrument reading or complete failure. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a pressure instrument with self-protection to solve the technical problems that when the measured pressure exceeds the design range of the instrument, the elastic element will cause material fatigue due to excessive deformation, resulting in irreversible plastic deformation in the light case and rupture in the severe case, and the overload pressure will be transmitted to the transmission mechanism, resulting in wear of the gear tooth surface and deformation and bending of the connecting rod, causing the pointer to get stuck in the light case and the transmission chain to break in the severe case.

[0005] To achieve the foregoing invention purpose, the technical solution adopted by the present invention includes: a pressure instrument with self-protection, including an instrument body. A pointer and a transmission mechanism are arranged inside the instrument body. An installation part is fixed to the instrument body. A transmission rod and a pressure conversion part are arranged inside the installation part. The pressure conversion part is connected to the transmission rod, and the transmission rod is connected to the transmission mechanism. When the pressure changes, the pressure conversion part makes the transmission mechanism operate through the transmission rod so that the pointer rotates accordingly. The mounting portion is a hollow tubular structure, the mounting portion is communicated with the inside of the instrument body, the pressure conversion element includes a first component and a second component located in the mounting portion, the first component is fixed to the side of the mounting portion close to the instrument body, the second component is slidably and sealedly connected with the mounting portion along the length direction of the mounting portion, a sealed space is formed between the first component and the second component, a third component is arranged between the first component and the second component, the third component is connected to the second component through a first elastic component, and a breathable gap is provided between the third component and the inner wall of the mounting portion; A connecting rod is fixed to the side of the third component facing away from the second component, and the connecting rod extends toward the first component at one end away from the third component, passes through the first component and is slidingly and sealingly connected to the first component, and the connecting rod is connected to the transmission rod at one end away from the third component, and a first limiting portion and a second limiting portion for limiting the movement of the third component are arranged between the first component and the second component, and the first limiting portion and the second limiting portion are respectively located on both sides of the third component.

[0006] Compared with the prior art, the advantages of the present invention include: (1) The present invention provides a self-protective pressure instrument. By setting a first limit part and a second limit part, the measuring range of the pressure instrument is controlled within an appropriate range. Even if the measured pressure exceeds the design range of the instrument, the third component will not continue to move under the action of the first limit part and the second limit part, so that the overload pressure will not be transmitted to the transmission mechanism through the transmission rod, and the pointer will not deflect beyond the range. In this way, the possibility of gear tooth surface wear and connecting rod deformation and bending is reduced, and the possibility of pointer jamming or transmission chain breakage is also reduced.

[0007] (2) The present invention provides a self-protective pressure instrument. The traditional elastic element (i.e., pressure conversion element) is replaced by a sealed space between a first component and a second component. Since the sealed space pressure conversion method does not rely on the deformation of the elastic element to transmit pressure, it effectively avoids problems such as material fatigue, plastic deformation or rupture caused by excessive deformation of the elastic element, and has better practicality.

[0008] (3) The present invention provides a self-protective pressure meter. When the internal pressure of the container to be measured changes slowly, the gas on both sides of the third member is slowly exchanged through the air-permeable gap to form a balance. The first elastic member stably transmits force to make the second and third members move synchronously. This is because the thrust generated by the deformation of the elastic member and the gas exchange resistance reach a dynamic balance. Under instantaneous pressure, the second component directly bears the pressure and generates displacement. Since the third component has a tendency to remain stationary and the third component is connected to the second component through the first elastic member, the first elastic member deforms rapidly, and the pressure cannot be transmitted to the third component in time. The third component lags behind, resulting in a relative displacement between the second component and the third component. Then, after the first elastic member deforms and absorbs energy, it applies to the third component at a relatively slow speed to make the third component move relatively slowly. Furthermore, the transmission rod and the transmission mechanism also operate slowly, thereby reducing the possibility of damage to the transmission mechanism and the pointer due to inertial force in the case of rapid response.

[0009] (4) For a pressure gauge with self-protection provided by the present invention, when the container to be measured is connected to the gauge, the two sides of the second component respectively bear the gas pressure inside the container to be measured and the pressure in the sealed space between the first component and the second component. The balance of the two-side pressures keeps the second component stationary. When the pressure of the container changes, the balance is broken, and the second component generates displacement. The different positions of the second component will reflect different pressure conditions of the container to be measured, realizing the measurement of the gas pressure inside the container to be measured.

[0010] (5) For a pressure gauge with self-protection provided by the present invention, when exceeding the measurement range, although the third component is restricted by the first limiting portion and the second limiting portion and does not continue to move, the second component will continue to move and cause the first elastic member to elastically deform. The elastic deformation of the first elastic member will absorb part of the pressure exerted on the second component by the gas inside the container to be measured, thereby reducing the pressure inside the sealed space and increasing the stability of the device.

[0011] Furthermore, a fixing rod is movably connected to the third component, a second elastic member for elastic reset of the fixing rod is arranged on the fixing rod, and a transmission member is arranged on the second component. When the internal pressure of the container to be measured instantaneously increases or decreases, the second component can generate displacement relative to the third component, and the fixing rod is moved through the transmission member to abut against the inner wall of the installation portion.

[0012] Furthermore, the third component is of a plate-like structure, a through hole is axially drilled through the center of the third component along its thickness direction, an installation hole is formed in the side wall of the through hole and extends out of the third component along the diameter direction of the through hole, the fixing rod is slidably arranged in the installation hole, the second elastic member is a second spring sleeved outside the fixing rod, one end of the second spring is connected to the fixing rod, and the other end is connected to the end of the installation hole; The transmission member is a push rod. One end of the push rod is fixed to the middle of the second member, and the other end extends along the length direction of the installation part and passes through the through hole. The transmission rod is composed of a first part, a second part and a third part. The first part and the second part are integrally connected by the third part. Conical structures are provided on the opposite sides of the first part and the second part, and the small ends of the two conical structures are arranged opposite to each other. When the first elastic member is in the natural state, the third part is located in the through hole, and the end of the fixing rod close to the center of the through hole abuts against the third part.

[0013] Further, the fixing rod includes a first rod body, a second rod body and a third elastic member. The first rod body and the second rod body are connected by the third elastic member. The end of the first rod body opposite to the second rod body abuts against the push rod. The opposite ends of the two conical structures respectively extend to the opposite ends of the first part and the second part so that the whole push rod has an "hourglass-shaped" structure.

[0014] Further, the third part is provided with a third limiting part and a fourth limiting part for limiting the position of the fixing rod. When the first elastic member is in the natural state, the end of the fixing rod close to the through hole is clamped between the third limiting part and the fourth limiting part.

[0015] Further, a coil is provided around the inner side of the through hole, and a magnetic rod is provided on the push rod; an alarm is provided outside the installation part, and the alarm is electrically connected to the coil. When the internal pressure of the container to be measured increases or decreases instantaneously, the magnetic rod can be inserted into the coil along with the push rod to generate an electric current, thereby making the alarm powered on and alarm.

[0016] Further, the end of the fixing rod close to the inner wall of the installation part is made of rubber material. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 It is a schematic structural diagram of an embodiment of the present invention; Figure 2 is Figure 1 a cross-sectional structural diagram of; Figure 3 It is a cross-sectional structural diagram of the second member and the third member part; Figure 4 It is a schematic structural diagram of the push rod.

[0019] Reference Signs: Instrument body 1, transmission rod 2, mounting part 3, connection head 4, first member 5, second member 6, third member 7, first elastic member 8, connecting rod 9, first limiting part 10, second limiting part 11, fixed rod 12, second elastic member 13, push rod 14, first part 15, second part 16, third part 17, conical structure 18, first rod body 19, second rod body 20, third elastic member 21, third limiting part 22, fourth limiting part 23, coil 24, magnetic rod 25, alarm 26. Detailed Description of the Invention

[0020] In view of the deficiencies in the prior art, the inventors of this case have proposed the technical solution of the present invention through long-term research and a large number of practices. The following will further explain and illustrate the technical solution, its implementation process and principle in combination with the drawings in the embodiments of the present application and specific implementation cases.

[0021] It should be noted that the embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention, and should not be construed as a limitation of the present invention. The described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, the present invention covers any substitution, modification, equivalent method and solution made within the spirit, principle and scope of the present invention defined by the claims. All other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present invention.

[0022] In the description of the present application, terms such as "first", "second", "third" and similar terms do not denote any order, quantity or importance, but are only used to distinguish different components. Similarly, terms such as "a" or "one" do not denote a quantity limitation, but mean that there is at least one. Terms such as "comprising" or "including" mean that the elements or items appearing before "comprising" or "including" cover the elements or items listed after "comprising" or "including" and their equivalents, and do not exclude other elements or items. Terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0023] In the description of the present application, the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present application. In addition, when using position terms such as both sides, outer side, upper and lower, etc., it should be understood that they are only used for easy understanding and description, considering that the structure may be oriented to other positions.

[0024] In the description of the present application, unless otherwise clearly defined and limited, the technical terms or scientific terms used should have the ordinary meaning understood by those with ordinary skills in the field to which the present application belongs. Terms such as "installation", "connection", "coupling", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or a contact connection or an integral connection; for those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to specific circumstances.

[0025] Please refer to Figures 1-4 , the present invention provides a technical solution: Refer to Figure 2 , a pressure gauge with self-protection, including a gauge body 1. A pointer and a transmission mechanism are arranged inside the gauge body 1. The transmission mechanism is connected to the pointer. An installation part 3 is fixed on the gauge body 1. A transmission rod 2 and a pressure conversion member are arranged inside the installation part 3. The pressure conversion member is connected to the transmission rod 2. The transmission rod 2 is connected to the transmission mechanism. When the pressure changes, the pressure conversion member makes the transmission mechanism operate through the transmission rod 2, and through the amplification of the transmission mechanism, the pointer rotates correspondingly, and then the measured pressure value is indicated on the dial.

[0026] Refer to Figure 2 , the installation part 3 is a hollow tubular structure, specifically a hollow circular tubular structure in this embodiment. The installation part 3 is in communication with the inside of the gauge body 1. Specifically, one end of the installation part 3 is in communication with the inside of the gauge body 1, and the other end is provided with a connection head 4 and is connected to the container to be measured through the connection head 4, such as the most common threaded connection method.

[0027] The pressure conversion component includes a first component 5 and a second component 6 located within the installation part 3. The first component 5 is fixed to the side of the installation part 3 close to the instrument body 1. In this embodiment, the first component 5 has a circular plate-like structure. It should be noted that the first component 5 is not limited to a circular plate-like structure. As long as the first component 5 is fixed inside the installation part 3 to close one end of the installation part 3 close to the instrument body 1 (in order to form a sealed space between it and the second component 6 to reflect the pressure condition inside the container to be measured). The second component 6 is slidably and sealingly connected to the installation part 3 along the length direction of the installation part 3, enabling it to move under the action of axial pressure. A sealed space is formed between the first component 5 and the second component 6. When the container to be measured is connected to this instrument, the two sides of the second component 6 respectively bear the gas pressure inside the container to be measured and the pressure in the sealed space between the first component 5 and the second component 6. Under normal circumstances, the pressure balance on both sides keeps the second component 6 stationary. When the container pressure changes, the balance is broken and the second component 6 generates displacement. Different positions of the second component 6 will reflect different pressure conditions of the container to be measured.

[0028] Refer to Figure 2 , a third component 7 is arranged between the first component 5 and the second component 6. The third component 7 is connected to the second component 6 through a first elastic member 8. There is a ventilation gap between the third component 7 and the inner wall of the installation part 3. When the internal pressure of the container to be measured changes slowly, the gases on both sides of the third component 7 are slowly exchanged through the ventilation gap to form a balance. The first elastic member 8 stably transmits force to make the second and third components 7 move synchronously. Under instantaneous pressure, the second component 6 directly bears the pressure and generates displacement. Since the third component 7 has a tendency to remain stationary and the third component 7 is connected to the second component 6 through the first elastic member 8. The first elastic member 8 deforms rapidly, and the pressure cannot be transmitted to the third component 7 in time. The third component 7 lags behind, resulting in a relative displacement between the second component 6 and the third component 7.

[0029] Subsequently, after the first elastic member 8 deforms to absorb energy, it applies force to the third component 7 to make the third component 7 move relatively slowly, and then makes the transmission rod 2 and the transmission mechanism also operate slower, thereby reducing the possibility of damage to the transmission mechanism and the pointer due to inertial force in the case of rapid response. Specifically, the first elastic member 8 is a first spring. One end of the first spring is fixedly connected to the second component 6, and the other end is fixedly connected to the third component 7.

[0030] Refer to Figure 2, a connecting rod 9 is fixed to the side of the third member 7 facing away from the second member 6. One end of the connecting rod 9 away from the third member 7 extends towards the first member 5, passes through the first member 5, and is slidably and sealingly connected to the first member 5. The slidable and sealing connection between the connecting rod 9 and the first member 5 is intended to maintain the sealed environment between the first member 5 and the second member 6. One end of the connecting rod 9 away from the third member 7 is connected to the transmission rod 2. The movement of the third member 7 will drive the movement of the connecting rod 9, and the movement of the connecting rod 9 will drive the movement of the transmission rod 2. Then, under the action of the transmission mechanism, the pointer rotates to indicate the corresponding reading on the instrument panel.

[0031] Refer to Figure 2 , a first limiting portion 10 and a second limiting portion 11 for restricting the movement of the third member 7 are provided between the first member 5 and the second member 6. The first limiting portion 10 and the second limiting portion 11 are respectively located on both sides of the third member 7. When the third member 7 moves to the first limiting portion 10 or the second limiting portion 11, the first limiting portion 10 or the second limiting portion 11 will restrict the continuous movement of the third member 7, and finally the pointer will not deflect. In other words, when the third member 7 moves to the first limiting portion 10 or the second limiting portion 11, the maximum measurement limit of this pressure gauge is reached. In this embodiment, the first limiting portion 10 is provided on the side of the third member 7 close to the second member 6. When the third member 7 moves to the first limiting portion 10, it is the minimum indication of the measurement. The second limiting portion 11 is provided on the side of the third member 7 away from the second member 6. When the third member 7 moves to the second limiting portion 11, it is the maximum indication of the measurement. In this embodiment, the first limiting portion 10 is of an annular structure and is coaxially fixed to the inner wall of the mounting portion 3 by welding. The first member 5 can serve as the second limiting portion 11.

[0032] Through the settings of the first limiting portion 10 and the second limiting portion 11, the measurement range of this pressure gauge is controlled within a suitable range. Even if the measured pressure exceeds the designed range of the instrument, under the action of the first limiting portion 10 and the second limiting portion 11, the third member 7 will not continue to move. Thus, the overload pressure will not be transmitted to the transmission mechanism through the transmission rod 2, and further the pointer will not deflect beyond the range. In this way, the possibility of gear tooth surface wear and deformation and bending of the connecting rod 9 is reduced, and at the same time, the possibility of pointer jamming or transmission chain breakage is also reduced.

[0033] In addition, the traditional elastic element (i.e., the pressure conversion element) is replaced by the sealed space between the first member 5 and the second member 6 in the present invention. Since the pressure conversion method of the sealed space does not rely on the deformation of the elastic element to transmit pressure, problems such as material fatigue, plastic deformation or rupture caused by excessive deformation of the elastic element are effectively avoided, and it has better practicability.

[0034] In addition, when the measurement range is exceeded, although the third component 7 is restricted by the first limiting portion 10 and the second limiting portion 11 and does not continue to move, the second component 6 will continue to move and cause the first elastic member 8 to deform elastically. The elastic deformation of the first elastic member 8 will absorb part of the pressure exerted by the gas in the container to be measured on the second component 6, thereby reducing the pressure inside the sealed space and increasing the stability of the device.

[0035] Preferably, when the third component 7 abuts against the first limiting portion 10, the space on the left side of the third component 7 is larger than the space on the right side of the third component 7, so that the space on the left side of the third component 7 is always larger than the space on the right side of the third component 7. Since the space on the left side of the third component 7 is always larger than the space on the right side of the third component 7, under the same volume change, its pressure decay is slower and the pressure difference is smaller, so that the second component 6 is more likely to move closer to the third component 7 in the face of instantaneous pressure changes.

[0036] Refer to Figure 2 Or 3, in this embodiment: A fixing rod 12 is movably connected to the third component 7, a second elastic member 13 for elastic reset of the fixing rod 12 is provided on the fixing rod 12, and a transmission member is provided on the second component 6.

[0037] When the internal pressure of the container to be measured increases or decreases instantaneously, the second component 6 will undergo a rapid displacement. Since the second component 6 and the third component 7 are flexibly connected by the first elastic member 8, the first elastic member 8 cannot transmit the displacement of the second component 6 to the third component 7 in time, so that the second component 6 can generate a displacement relative to the third component 7, and at the same time the first elastic member 8 is elastically compressed. The displacement of the second component 6 relative to the third component 7 can cause the transmission member to displace relative to the fixing rod 12, and then drive the fixing rod 12 to generate a displacement so that the fixing rod 12 abuts inside the mounting portion 3, thereby fixing the third component 7 inside the mounting portion 3. Subsequently, since the third component 7 is fixed inside the mounting portion 3, the third component 7 will not undergo a rapid displacement along with the second component 6, so that the transmission rod 2 and the pointer will not have a rapid reaction.

[0038] When the pressure is restored, the second component 6 moves in the opposite direction relative to the third component 7 (since the third component 7 is fixed inside the mounting portion 3 at this time and does not move accordingly), and then drives the transmission member to move in the opposite direction until the transmission member and the fixing rod 12 return to their original positions. The fixing rod 12 then returns to its original state under the action of the second elastic member 13. After the fixing rod 12 is restored, the locking of the third component 7 is released, and normal measurement work can be carried out subsequently. The first elastic member 8 also elastically recovers during this process.

[0039] Due to the fact that after the instantaneous pressure, the first elastic member 8 will cause fluctuations in the transmission mechanism under the driving action of the third member 7, and the pointer will rotate back and forth, which may increase wear. In the above setting, when the internal pressure of the container to be measured increases or decreases instantaneously, the third member 7 is fixed in a stationary state through the fixing rod 12. When the pressure recovers, the fixing rod 12 releases the fixation of the third member 7. During the instantaneous increase or decrease and recovery of the internal pressure of the container to be measured, the transmission rod 2 and the transmission mechanism remain stationary, which not only provides anti-inertia impact protection for the transmission rod 2 and the transmission mechanism, but also reduces the fluctuations of the transmission mechanism and the possibility of wear caused by the pointer rotating back and forth. It should be noted that the above setting has good applicability in scenarios such as water hammer tests and burst tests where the pressure returns to the original state after transient high pressure. In addition, in chemical production, when an exothermic or endothermic reaction occurs in a closed container, the pressure will increase or decrease instantaneously, and then slowly drop due to a decrease or increase in temperature. In such cases, it also has good applicability.

[0040] Refer to Figures 2-4 , in this embodiment: The third member 7 is a plate-like structure. A through hole is formed through the center of the third member 7 along its thickness direction. An installation hole is formed on the side wall of the through hole and extends out of the third member 7 along the diameter direction of the through hole. The fixing rod 12 is slidably arranged in the installation hole. By applying an external force to make the fixing rod 12 slide in the installation hole, the end of the fixing rod 12 away from the through hole can be made to approach or move away from the inner wall of the installation part 3. When approaching and abutting, the fixation of the third member 7 is achieved. When moving away and disengaging, the fixation of the third member 7 is released. The second elastic member 13 is a second spring sleeved outside the fixing rod 12. One end of the second spring is connected to the fixing rod 12, and the other end is connected to the end of the installation hole. The second spring will be elastically stressed during the sliding process of the fixing rod 12 and can return to its original state under the elastic force of the second spring when the external force is withdrawn.

[0041] The transmission member is a push rod 14. One end of the push rod 14 is fixed to the middle of the second member 6, and the other end extends through the through hole along the length direction of the installation part 3. When the second member 6 slides along the length direction of the installation part 3, it can synchronously drive the push rod 14 to move along the length direction of the installation part 3. The transmission rod 2 is composed of a first part 15, a second part 16 and a third part 17. The first part 15 and the second part 16 are integrally connected through the third part 17. Both the first part 15 and the second part 16 have a tapered structure 18 on the opposite side. The tapered structure 18 is a frustum-shaped structure. The side surface of the tapered structure 18 is an inclined plane. The small ends of the two tapered structures 18 are arranged opposite to each other, that is, the dimensions of the opposite ends of the two tapered structures 18 are larger than those of the relative ends. When the first elastic member 8 is in a natural state, the third part 17 is located in the through hole, and the end of the fixing rod 12 close to the center of the through hole abuts against the third part 17.

[0042] When the internal pressure of the container to be measured increases or decreases instantaneously, the push rod 14 moves relative to the fixed rod 12, enabling the fixed rod 12 to move upward along the inclined surface of the conical structure 18, so that the end of the fixed rod 12 away from the through hole abuts against the inner wall of the mounting portion 3 to fix the third member 7. Under the action of the second spring, the end of the fixed rod 12 close to the through hole always abuts against the inclined surface of the conical structure 18; When the pressure recovers, the push rod 14 moves in the opposite direction, and the fixed rod 12 moves downward along the inclined surface of the conical structure 18 under the elastic force of the second spring. The end of the fixed rod 12 away from the through hole disengages from the contact with the inner wall of the mounting portion 3, realizing the release of the fixation of the third member 7. In addition, the second spring additionally provides a driving force for the fixed rod 12 to move downward along the inclined surface of the conical structure 18, which can accelerate the reset of the fixed rod 12.

[0043] Refer to Figures 2-4 In this embodiment: The fixed rod 12 includes a first rod body 19, a second rod body 20 and a third elastic member 21. The first rod body 19 and the second rod body 20 are connected by the third elastic member 21. Specifically, the third elastic member 21 is a third spring. The third spring is arranged between the first rod body 19 and the second rod body 20. One end of the third spring is fixedly connected to the first rod body 19, and the other end is fixedly connected to the second rod body 20. The end of the first rod body 19 opposite to the second rod body 20 abuts against the push rod 14.

[0044] The opposite ends of the two conical structures 18 respectively extend to the opposite ends of the first part 15 and the second part 16. That is, the first part 15 and the second part 16 as a whole present a frustum structure, and are connected by a cylindrical third part 17 in the middle. The side surface of the first part 15 is entirely an inclined surface, and the push rod 14 as a whole has an "hourglass-shaped" structure, that is, a double-cone structure with a small middle and large ends.

[0045] Since the elastic force of the first elastic member 8 gradually increases during the displacement of the second member 6 under the instantaneous pressure, the thrust applied by the first elastic member 8 to the third member 7 gradually increases. Due to the entire side surface of the first part 15 being an inclined surface, the end of the fixed rod 12 close to the through hole always slides on the inclined surface, and as the displacement length of the second member 6 gradually increases, the rising distance of the fixed rod 12 along the inclined surface gradually increases. Furthermore, the elastic compression force of the third spring gradually increases, so the force with which the fixed rod 12 abuts against the inner wall of the mounting portion 3 gradually increases, and the frictional force between the fixed rod 12 and the inner wall of the mounting portion 3 gradually increases, which is adapted to the gradually increasing thrust applied by the first elastic member 8 to the third member 7, realizing the dynamic adjustment of the frictional force between the fixed rod 12 and the inner wall of the mounting portion 3.

[0046] Refer to Figures 2-4, in this embodiment: The third part 17 is provided with a third limiting part 22 and a fourth limiting part 23 for restricting the position of the fixing rod 12. Specifically, the third limiting part 22 and the fourth limiting part 23 are ring-shaped structures and are coaxially fixed on the outer wall of the third part 17. When the first elastic member 8 is in a natural state, the end of the fixing rod 12 close to the through hole is clamped between the third limiting part 22 and the fourth limiting part 23. Specifically, the third limiting part 22 is located on the left side of the end of the fixing rod 12 close to the through hole, and the fourth limiting part 23 is located on the right side of the end of the fixing rod 12 close to the through hole. Since the influence on the transmission mechanism and the pointer is not significant under the condition of small instantaneous pressure change, the third limiting part 22 and the fourth limiting part 23 play a certain role in restricting the position of the fixing rod 12. When the pressure change is not very large, the fixing rod 12 cannot cross the third limiting part 22 and the fourth limiting part 23, so that the fixing rod 12 cannot fix the third component 7 to the inner wall of the installation part 3, thereby defining the instantaneous pressure change within a suitable critical value and avoiding the adverse impact on the normal reading caused by the activation of the protection mechanism under the condition of small instantaneous pressure change.

[0047] Refer to Figure 2 , in this embodiment: A coil 24 is provided around the inner side of the through hole, and a magnetic rod 25 is provided on the push rod 14; An alarm 26 is provided outside the installation part 3, and the alarm 26 is electrically connected to the coil 24. When the pressure inside the container to be measured increases or decreases instantaneously, the magnetic rod 25 can be inserted into the coil 24 along with the push rod 14. When the magnetic rod 25 moves, the magnetic field strength at the position where the coil 24 is located changes, resulting in a change in magnetic flux. The change in magnetic flux will generate an induced electromotive force, and the induced electromotive force drives the directional movement of free electrons in the coil 24 to form an instantaneous current. Moreover, the current generated by the single movement of the magnetic rod 25 is an instantaneous pulse current. The two ends of the coil 24 are connected to the alarm 26 to form a closed loop. The instantaneous pulse current will activate the alarm 26 to give an alarm. For example, an electronic alarm with higher pulse sensitivity.

[0048] In this embodiment: The end of the fixing rod 12 close to the inner wall of the installation part 3 is made of rubber material. The above settings have the following two effects. One is to increase the friction between the fixing rod 12 and the inner wall of the installation part 3 and improve the fixing effect; The other is to provide additional buffer protection for the inner wall of the installation part 3 to prevent the fixing rod 12 from damaging the inner wall of the installation part 3 due to excessive extrusion force on the inner wall of the installation part 3.

[0049] It should be understood that the above embodiments are only used to illustrate the technical concept and features of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can be made. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A self - protective pressure gauge, comprising a gauge body. Inside the gauge body, a pointer and a transmission mechanism are provided. The gauge body is fixed with a mounting part. Inside the mounting part, a transmission rod and a pressure conversion part are provided. The pressure conversion part is connected to the transmission rod, and the transmission rod is connected to the transmission mechanism. When the pressure changes, the pressure conversion part makes the transmission mechanism operate through the transmission rod so that the pointer rotates correspondingly. It is characterized in that: The mounting part is a hollow tubular structure, and the mounting part is in communication with the inside of the gauge body. The pressure conversion part includes a first component and a second component located inside the mounting part. The first component is fixed on the side of the mounting part close to the gauge body. The second component is slidably and sealingly connected to the mounting part along the length direction of the mounting part. A sealed space is formed between the first component and the second component. A third component is arranged between the first component and the second component. The third component is connected to the second component through a first elastic member. There is a ventilation gap between the third component and the inner wall of the mounting part; A connecting rod is fixed on the side of the third component facing away from the second component. The end of the connecting rod away from the third component extends towards the first component and passes through the first component and is slidably and sealingly connected to the first component. The end of the connecting rod away from the third component is connected to the transmission rod. A first limiting part and a second limiting part for restricting the movement of the third component are arranged between the first component and the second component. The first limiting part and the second limiting part are respectively located on both sides of the third component.

2. The self-protective pressure gauge according to claim 1, characterized in that: A fixing rod is movably connected to the third component. A second elastic member for elastic reset of the fixing rod is arranged on the fixing rod. A transmission part is arranged on the second component. When the pressure inside the container to be measured instantaneously increases or decreases, the second component can generate a displacement relative to the third component, and make the fixing rod move through the transmission part so that the fixing rod abuts against the inner wall of the mounting part.

3. The self-protective pressure gauge according to claim 2, characterized in that: The third component is a plate - like structure. A through - hole is axially drilled through the center of the third component along its thickness direction. A mounting hole is drilled in the side wall of the through - hole and extends through the third component along the diameter direction of the through - hole. The fixing rod is slidably arranged in the mounting hole. The second elastic member is a second spring sleeved outside the fixing rod. One end of the second spring is connected to the fixing rod, and the other end is connected to the end of the mounting hole; The transmission part is a push rod. One end of the push rod is fixed in the middle of the second component, and the other end extends along the length direction of the mounting part and passes through the through - hole. The transmission rod is composed of a first part, a second part and a third part combined. The first part and the second part are integrally connected by the third part. Conical structures are provided on the opposite sides of the first part and the second part, and the small ends of the two conical structures are arranged opposite to each other. When the first elastic member is in a natural state, the third part is located inside the through - hole, and the end of the fixing rod close to the center of the through - hole abuts against the third part.

4. The self-protective pressure gauge according to claim 3, wherein: The fixing rod includes a first rod body, a second rod body and a third elastic member. The first rod body and the second rod body are connected by the third elastic member. The end of the first rod body facing away from the second rod body abuts against the push rod; The opposite ends of the two conical structures respectively extend to the opposite ends of the first part and the second part so that the whole push rod has an "hourglass-shaped" structure.

5. The self-protective pressure gauge according to claim 4, characterized in that: The third part is provided with a third limiting part and a fourth limiting part for limiting the position of the fixing rod. When the first elastic member is in a natural state, the end of the fixing rod close to the through hole is clamped between the third limiting part and the fourth limiting part.

6. A pressure gauge with self - protection according to any one of claims 3 - 5, characterized in that: A coil is disposed around the inner side of the through hole, and a magnetic rod is disposed on the push rod; an alarm is disposed outside the mounting part, and the alarm is electrically connected to the coil. When the internal pressure of the container to be measured instantaneously increases or decreases, the magnetic rod can be inserted into the coil along with the push rod to generate an electric current, thereby causing the alarm to be powered on and give an alarm.

7. The self-protective pressure gauge according to claim 6, wherein: One end of the fixing rod close to the inner wall of the mounting part is made of rubber material.

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