Self-compensating bellows and self-compensating gas density measuring device

Abstract

The present application relates to the technical field of gas density measuring devices, and provides a self-compensating bellows. By arranging a plurality of compensating elastic parts that fit together with a plurality of corrugated elastic parts of a corrugated outer tube, and the thermal expansion coefficients of the compensating elastic parts and the corrugated elastic parts are inconsistent, when the temperature of the gas in the self-compensating bellows changes, each compensating elastic part undergoes a deformation amount different from that of each corrugated elastic part, so as to overcome the influence of temperature on the deformation of each corrugated elastic part, thereby enabling the self-compensating bellows to achieve temperature self-compensation. The present application provides a self-compensating gas density measuring device, which uses the self-compensating bellows as a measuring mechanism, so that the device does not need to install additional temperature compensation elements such as a compensating gas chamber or a bimetallic strip, thereby simplifying the structure, reducing costs, and solving the technical problems of the complex structure and high cost of the temperature compensation method of the existing gas density measuring equipment.

Description

Technical Field

[0001] The present application relates to the technical field of gas density measuring devices, and in particular to a self-compensating bellows and a self-compensating gas density measuring device. Background Art

[0002] Circuit breakers are crucial electrical equipment in power systems. They ensure the distribution and control of power by closing and opening circuits according to control quality during normal system operation. They also automatically and quickly disconnect circuits in the event of faults such as overload, short circuit, or undervoltage, preventing the spread and expansion of the fault. A circuit breaker failure can cause significant economic losses. To ensure reliable circuit breaker operation, a gas density relay can monitor the density of sulfur hexafluoride gas within the circuit breaker in real time, ensuring it meets relevant standards and maintains optimal long-term operation. Furthermore, the gas density relay can control the closing and opening of the circuit breaker through its node output signals. Thus, the circuit breaker and gas density relay work together to ensure the safe and stable operation of the power system.

[0003] Currently, gas density relays primarily use Bourdon tube and bellows measurement methods. Bellows measurement offers greater accuracy and sensitivity, but due to the inherent characteristics of bellows, temperature compensation is required when the ambient temperature changes.

[0004] The commonly used temperature compensation methods currently used are to use a sealed compensation air chamber or to add a bimetallic strip as a temperature compensation element.

[0005] Specifically, temperature compensation using a sealed compensation chamber involves changing the pressure of the gas inside the chamber as the ambient temperature changes. This pressure change is then compared with the pressure change of the measured gas to compensate for the change. However, this compensation method requires a matching inflatable and sealing structure, as well as related equipment, which is costly.

[0006] The method of using a bimetallic strip for temperature compensation involves connecting one end of the bimetallic strip to a bellows and the other end to the movement. When the bellows senses the pressure of the gas being measured and displaces, it drives the bimetallic strip to move. The elastic deformation and displacement characteristics of the bimetallic strip compensate for the pressure changes in the bellows caused by temperature changes, allowing the pointer to more accurately indicate the gas density. However, this compensation method adds a bimetallic strip, which increases the structural complexity of the gas density relay and the cost. Summary of the Invention

[0007] In view of the above-mentioned shortcomings of the prior art, the purpose of this application is to provide a self-compensating bellows and a self-compensating gas density measuring device to solve the technical problems of the complex structure and high cost of the temperature compensation method of the existing gas density measuring equipment.

[0008] To achieve the above-mentioned purpose and other related purposes, the first aspect of the present application provides a self-compensating bellows, which includes: a bellows outer tube, which is a corrugated shell including a plurality of corrugated elastic parts; a plurality of compensating elastic parts, each of which is connected to the bellows outer tube and fits together with each corrugated elastic part; wherein, when the gas density in the self-compensating bellows changes, each corrugated elastic part deforms under the action of the gas pressure, driving the corrugated outer tube to stretch or contract as a whole; the thermal expansion coefficients of the compensating elastic part and the corrugated elastic part are inconsistent, and when the gas temperature in the self-compensating bellows changes, each compensating elastic part undergoes a different deformation amount from each corrugated elastic part, so as to overcome the influence of temperature on the deformation of each corrugated elastic part, thereby keeping the corrugated outer tube unchanged as a whole.

[0009] In some embodiments of the first aspect of the present application, the corrugated elastic member includes: a first corrugated connection part, a second corrugated connection part, a third corrugated connection part, a first corrugated bending part and a second corrugated bending part; wherein, the two ends of the first corrugated bending part are respectively connected to one end of the first corrugated connection part and one end of the second corrugated connection part, and the two ends of the second corrugated bending part are respectively connected to the other end of the second corrugated connection part and one end of the third corrugated connection part; under the action of gas pressure, the angle between each corrugated connection part and each corrugated bending part of the self-compensating bellows changes, and the corrugated elastic member expands or contracts, driving the corrugated outer tube to stretch or contract as a whole; the compensating elastic member includes: a first compensating connection part, a second compensating connection part and a compensating bending part; wherein, the two ends of the compensating bending part are respectively connected to one end of the first compensating connection part and one end of the second compensating connection part; under the action of gas pressure, the angle between each compensating connection part and each compensating bending part of the self-compensating bellows changes, and the compensating elastic member expands or contracts.

[0010] In some embodiments of the first aspect of the present application, each compensation elastic member is respectively arranged on the inner side of each corrugated elastic member; wherein, the first compensation connection portion, the compensation bending portion and the second compensation connection portion of each compensation elastic member are respectively fitted with the first corrugated connection portion, the first corrugated bending portion and the second corrugated connection portion of each corrugated elastic member; the thermal expansion coefficient of the compensation elastic member is smaller than the thermal expansion coefficient of the corrugated elastic member.

[0011] In some embodiments of the first aspect of the present application, each compensation elastic member is respectively arranged on the inner side of each corrugated elastic member; wherein, the first compensation connection portion, the compensation bending portion and the second compensation connection portion of each compensation elastic member are respectively fitted with the second corrugated connection portion, the second corrugated bending portion and the third corrugated connection portion of each corrugated elastic member; the thermal expansion coefficient of the compensation elastic member is greater than the thermal expansion coefficient of the corrugated elastic member.

[0012] In some embodiments of the first aspect of the present application, each compensation elastic member is respectively arranged on the outside of each corrugated elastic member; wherein, the first compensation connection portion, the compensation bending portion and the second compensation connection portion of each compensation elastic member are respectively fitted with the first corrugated connection portion, the first corrugated bending portion and the second corrugated connection portion of each corrugated elastic member; the thermal expansion coefficient of the compensation elastic member is greater than the thermal expansion coefficient of the corrugated elastic member.

[0013] In some embodiments of the first aspect of the present application, each compensation elastic member is respectively arranged on the outside of each corrugated elastic member; wherein, the first compensation connection portion, the compensation bending portion and the second compensation connection portion of each compensation elastic member are respectively fitted with the second corrugated connection portion, the second corrugated bending portion and the third corrugated connection portion of each corrugated elastic member; the thermal expansion coefficient of the compensation elastic member is smaller than the thermal expansion coefficient of the corrugated elastic member.

[0014] To achieve the above-mentioned object and other related objects, a second aspect of the present application provides a self-compensating gas density measuring device, comprising: a measuring mechanism, comprising: a self-compensating bellows as described in any of the above-mentioned embodiments; a bellows top cover and a bellows bottom cover are respectively provided at both ends of the self-compensating bellows, forming a closed air cavity that is connected to the gas to be measured through an air inlet hole in the bellows bottom cover, so that the gas to be measured flows into the closed air cavity; the bellows top cover is connected to one end of a driving mechanism, and the other end of the driving mechanism is connected to an indicating mechanism; wherein, when the gas density of the gas to be measured changes, the self-compensating bellows contracts or extends under the action of the gas pressure, and drives the driving mechanism to move up and down, thereby driving the indicating mechanism to rotate and indicate the corresponding gas density value; when the gas temperature of the gas to be measured changes, the self-compensating bellows undergoes deformation different from that of the other bellows elastic members through each compensating elastic member to overcome the influence of temperature on the deformation of each bellows elastic member, thereby maintaining the self-compensating bellows unchanged, and thereby maintaining the driving mechanism and the indicating mechanism unchanged.

[0015] In some embodiments of the second aspect of the present application, the driving mechanism includes: a guide rod, one end of which is connected to the bellows top cover through a cylindrical pin; when the self-compensating bellows contracts or extends, it drives the bellows top cover to move up and down, and then drives the guide rod to move up and down; a slider, which is fixedly connected to the other end of the guide rod, and when the self-compensating bellows contracts or extends, the slider follows the guide rod to move up and down; a first guide groove is provided on the slider, which is connected to the indicating mechanism, and when the slider moves up and down, it drives the indicating mechanism to rotate and indicates the corresponding gas density value.

[0016] In some embodiments of the second aspect of the present application, the indicating mechanism includes: a movement, including: sector teeth and a pointer shaft meshingly connected to one end of the sector teeth through a gear structure; a second guide groove is provided at the other end of the sector teeth, and a first connecting member passes through the second guide groove and the first guide groove of the slider to connect the sector teeth and the slider; a pointer, one end of the pointer is connected to the pointer shaft; a dial, the dial is arranged between the movement and the pointer, and a scale of gas density value is marked on the side facing the pointer; when the slider moves up and down, it drives the sector teeth to rotate, and drives the pointer shaft to rotate through the gear structure, and then drives the pointer to rotate with the connection point with the pointer shaft as the center. After the pointer rotates, it aligns with the scale marked on the dial, which is the gas density value of the gas to be measured.

[0017] In some embodiments of the second aspect of the present application, the self-compensating gas density measuring device also includes: a supporting mechanism; wherein the supporting mechanism includes: an outer cylinder covered outside the self-compensating bellows; an air inlet portion is provided at the lower end of the outer cylinder, and the air inlet portion is provided with an air inlet channel; the air inlet portion is fixedly connected to the bottom cover of the bellows and is connected to the measuring gas pipe for storing the gas to be measured, so that the air inlet channel is respectively connected to the closed air cavity and the gas to be measured; when the gas density of the gas to be measured changes, the gas pressure in the closed air cavity changes; a cylinder cover is provided at the upper end of the outer cylinder, and one or more support columns are provided on the top of the cylinder cover; an L-shaped support frame, including: a first support portion and a second support portion arranged perpendicular to the first support portion; the first support portion is fixedly connected to each of the support columns, and the second support portion is fixedly connected to the dial through one or more second connecting members.

[0018] As described above, the present application provides a self-compensating bellows, which is provided with a plurality of compensating elastic members that fit together with the plurality of corrugated elastic members of the corrugated outer tube, and the thermal expansion coefficients of the compensating elastic members and the corrugated elastic members are inconsistent, so that when the temperature of the gas in the self-compensating bellows changes, each compensating elastic member undergoes a deformation amount different from that of each corrugated elastic member, so as to overcome the influence of temperature on the deformation of each corrugated elastic member, thereby enabling the self-compensating bellows to achieve temperature self-compensation. The present application provides a self-compensating gas density measuring device, which uses the self-compensating bellows as a measuring mechanism, so that the device does not need to install additional temperature compensation elements such as a compensating gas chamber or a bimetallic strip, thereby having the following beneficial effects: simplifying the structure of the self-compensating gas density measuring device and reducing costs, solving the technical problems of the complex structure and high cost of the temperature compensation method of the existing gas density measuring equipment; at the same time, the product process is simple and more suitable for batch production operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Shown is a schematic diagram of the cross-sectional structure of a self-compensating bellows in one embodiment of the present application.

[0020] Figure 2 Shown is a schematic structural diagram of a corrugated elastic member and a compensating elastic member in one embodiment of the present application.

[0021] Figure 3 Shown is a schematic structural diagram of a corrugated elastic member and a compensating elastic member in one embodiment of the present application.

[0022] Figure 4 Shown is a schematic structural diagram of a corrugated elastic member and a compensating elastic member in one embodiment of the present application.

[0023] Figure 5 Shown is a schematic structural diagram of a corrugated elastic member and a compensating elastic member in one embodiment of the present application.

[0024] Figure 6 Shown is a structural schematic diagram of a self-compensating gas density measurement device in one embodiment of the present application.

[0025] Figure 7 Shown is a connection diagram of a measuring mechanism, a driving mechanism, and an indicating mechanism in one embodiment of the present application.

[0026] Figure 8 Shown is a structural schematic diagram of a self-compensating gas density measurement device in one embodiment of the present application.

[0027] Figure 9 Shown is a schematic structural diagram of a movement in one embodiment of the present application.

[0028] Component number description

[0029] 1. Measuring mechanism

[0030] 11 Self-compensating bellows

[0031] 111 Corrugated elastic parts

[0032] 111a First corrugated connecting portion

[0033] 111b Second corrugated connection portion

[0034] 111c Third corrugated connection part

[0035] 111d First corrugated bending part

[0036] 111e Second corrugated bend

[0037] 112 Compensating elastic piece

[0038] 112a First compensation connection portion

[0039] 112b Second compensation connection portion

[0040] 112c Compensation bending part

[0041] 12 Bellows cover

[0042] 13 Bellows bottom cover

[0043] 131 air intake

[0044] 14 Sealed air cavity

[0045] 2 Drive mechanism

[0046] 21 Guide rod

[0047] 22 cylindrical pins

[0048] 23 Sliders

[0049] 231 First guide groove

[0050] 3 Indicating agency

[0051] 31 movement

[0052] 311 sector teeth

[0053] 312 gear structure

[0054] 313 pointer axis

[0055] 314 Second guide groove

[0056] 315 first support plate

[0057] 316 Second support plate

[0058] 317 First fixed column

[0059] 318 Second fixed column

[0060] 319 hairspring

[0061] 32 pointers

[0062] 33 dial

[0063] 34 First connecting piece

[0064] 4 Support mechanism

[0065] 41 outer cylinder

[0066] 42 Air intake

[0067] 421 intake duct

[0068] 43 cylinder cover

[0069] 431 Support Column

[0070] 44 L-shaped support frame

[0071] 441 First Supporting Part

[0072] 442 Second support part

[0073] 45 Second connecting piece DETAILED DESCRIPTION

[0074] The following describes the embodiments of the present application through specific examples. Those skilled in the art can easily understand the other advantages and effects of the present application from the content disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other unless they conflict.

[0075] In the embodiments of this application, terms such as "first" and "second" are used to distinguish between identical or similar items with substantially the same function or effect. For example, the terms "first connector" and "second connector" are used solely to distinguish between the different connectors and do not define the order in which they are connected. Those skilled in the art will understand that terms such as "first" and "second" do not define the quantity or order of execution, and that terms such as "first" and "second" do not necessarily define differences.

[0076] In order to solve the problems in the above background technology, the present invention provides a self-compensating bellows and a self-compensating gas density measuring device, aiming to solve the technical problems that the temperature compensation method of the existing gas density measuring equipment is complex in structure and high in cost.

[0077] In order to make the purpose, technical solutions and advantages of this application more clear, the following embodiments and the accompanying drawings are used to further explain the technical solutions in the embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0078] like Figure 1 FIG2 shows a schematic diagram of the structure of a self-compensating bellows 11 in an embodiment of the present application. The self-compensating bellows 11 in this embodiment comprises a bellows outer tube and a plurality of compensating elastic members 112 connected to the bellows outer tube. The bellows outer tube is a corrugated shell comprising a plurality of bellows elastic members 111, and each bellows elastic member 111 is in contact with a respective compensating elastic member 112.

[0079] It should be understood that the bellows can expand and contract under the action of external pressure. Based on this, it can be used as the main measuring element of the gas density measuring device, which is used to expand and contract under the action of gas pressure when the gas density of the gas to be measured changes, thereby monitoring the gas density changes of the gas to be measured in real time.

[0080] According to the ideal gas state equation And the formula for calculating the amount of substance , the calculation formula for gas density can be obtained as .in, is the gas pressure, is the gas volume, is the amount of substance, is the molar gas constant, is the gas temperature, is the gas density, is the mass of the gas, is the molar mass of the gas.

[0081] From this we can see that for the same type of gas, its molar mass Fixed, when the gas temperature remains unchanged, the gas density is proportional to the gas pressure. That is, when the gas density of the gas to be measured increases, the gas pressure on the bellows also increases, causing the bellows to stretch and deform; when the gas density of the gas to be measured decreases, the gas pressure on the bellows also decreases, causing the bellows to shrink and deform.

[0082] However, when the gas temperature changes, the gas pressure also changes. Specifically, as the gas temperature of the measured gas increases, the gas expands, and the gas pressure increases. This increases the gas pressure on the bellows, causing the bellows to stretch and deform. Similarly, as the gas temperature of the measured gas decreases, the gas pressure decreases, which reduces the gas pressure on the bellows, causing the bellows to contract and deform. In this case, bellows deformation caused by temperature changes can seriously affect the accuracy of the monitored gas density.

[0083] In this embodiment, when the gas density in the self-compensating bellows changes, each bellows elastic member 111 is deformed under the action of the gas pressure, driving the entire bellows outer tube to extend or contract, thereby supporting the measurement of gas density.

[0084] More importantly, each compensation elastic member 112 is respectively fitted with each corrugated elastic member 111 , and the thermal expansion coefficients of the compensation elastic member 112 and the corrugated elastic member 111 are inconsistent, thereby forming a bimetallic structure.

[0085] It should be understood that a bimetallic structure refers to a composite structure composed of two different metals or alloys, consisting of an active layer and a passive layer of metals with different thermal expansion coefficients. The thermal expansion coefficient of the active layer is greater than that of the passive layer. When the bimetallic structure is heated, the active layer expands more, while the passive layer expands less, causing the bimetallic structure to bend toward the passive layer.

[0086] When the temperature of the gas in the self-compensating bellows changes, based on the bimetallic structure, each compensating elastic member 112 can undergo a deformation amount different from that of each corrugated elastic member 111, so as to overcome the influence of temperature on the deformation of each corrugated elastic member 111, thereby keeping the overall corrugated outer tube unchanged, ensuring that the self-compensating bellows can achieve temperature self-compensation when used in a gas density measuring device, always indicating the gas density value at a specified temperature, and ensuring the accuracy of gas density measurement.

[0087] In one embodiment, if Figures 2 to 5 As shown, the corrugated elastic member 111 includes a first corrugated connecting portion 111a, a second corrugated connecting portion 111b, a third corrugated connecting portion 111c, a first corrugated bent portion 111d, and a second corrugated bent portion 111e. The first corrugated bent portion 111d has two ends connected to one end of the first corrugated connecting portion 111a and one end of the second corrugated connecting portion 111b, respectively; the second corrugated bent portion 111e has two ends connected to the other end of the second corrugated connecting portion 111b and one end of the third corrugated connecting portion 111c, respectively. In a preferred embodiment, the first corrugated bent portion 111d and the second corrugated bent portion 111e are semicircular.

[0088] In this embodiment, under the action of gas pressure, the angle between each corrugated connecting portion and each corrugated bending portion of the self-compensating bellows changes, and the corrugated elastic member 111 expands or contracts, driving the overall extension or contraction of the corrugated outer tube.

[0089] like Figures 2 to 5 As shown, the compensating spring member 112 is U-shaped and includes a first compensating connection portion 112a, a second compensating connection portion 112b, and a compensating bent portion 112c. The two ends of the compensating bent portion 112c are connected to one end of the first compensating connection portion 112a and one end of the second compensating connection portion 112b, respectively. When the gas density in the self-compensating bellows changes, the angle between each compensating connection portion and each compensating bent portion changes, causing the compensating spring member 112 to expand or contract. In a preferred embodiment, the compensating bent portion 112c is semicircular.

[0090] In this embodiment, under the action of gas pressure, the angles between the compensation connecting portions and the compensation bending portions of the self-compensating bellows change, and the compensation elastic member 112 expands or contracts.

[0091] In a specific embodiment, if Figure 2 As shown, each compensating elastic member 112 is respectively disposed inside each corrugated elastic member 111. The first compensating connection portion 112a, the compensating bent portion 112c, and the second compensating connection portion 112b of each compensating elastic member 112 are respectively in contact with the first corrugated connection portion 111a, the first corrugated bent portion 111d, and the second corrugated connection portion 111b of each corrugated elastic member 111.

[0092] At this time, the thermal expansion coefficient of the compensation elastic member 112 is smaller than the thermal expansion coefficient of the corrugated elastic member 111 .

[0093] It should be understood that the thermal expansion coefficient is a physical quantity that characterizes the dimensional change characteristics of an object when heated. The calculation formula for the thermal expansion coefficient is: ;in, is the coefficient of thermal expansion, is the expansion deformation, is the initial amount, is the temperature change. When the material is constant, the greater the thermal expansion coefficient, the greater the expansion deformation.

[0094] When the temperature of the gas to be measured rises, the gas pressure on the corrugated elastic member 111 and the compensating elastic member 112 attached thereto increases. Under the action of the gas pressure, the corrugated elastic member 111 and the compensating elastic member 112 undergo elongation and deformation. However, due to the inconsistency in thermal expansion coefficients, the compensating elastic member 112 undergoes a different amount of elongation and deformation than the corrugated elastic member 111. Specifically, the thermal expansion coefficient of the compensating elastic member 112 is smaller than that of the corrugated elastic member 111. Therefore, for the same temperature change, the elongation and deformation of the compensating elastic member 112 is smaller than that of the corrugated elastic member 111. The compensating elastic member 112 fits with the corrugated elastic member 111, and the smaller elongation deformation of the compensating elastic member 112 causes the corrugated elastic member 111 to contract, thereby overcoming the elongation deformation of the corrugated elastic member 111, so that the corrugated elastic member 111 does not expand and contract due to temperature changes, thereby allowing the corrugated outer tube to remain unchanged as a whole when the temperature changes.

[0095] Similarly, when the temperature of the gas to be measured decreases, the gas pressure on the corrugated elastic member 111 and the compensating elastic member 112 attached thereto decreases. Under the action of the gas pressure, the corrugated elastic member 111 and the compensating elastic member 112 contract and deform. However, because the thermal expansion coefficient of the compensating elastic member 112 is smaller than that of the corrugated elastic member 111, the amount of contraction and deformation of the compensating elastic member 112 is smaller than that of the corrugated elastic member 111. The compensating elastic member 112 and the corrugated elastic member 111 are attached to each other, and the smaller contraction and deformation of the compensating elastic member 112 causes the corrugated elastic member 111 to expand, overcoming the contraction and deformation of the corrugated elastic member 111, preventing the corrugated elastic member 111 from expanding or contracting due to temperature changes, thereby ensuring that the overall corrugated outer tube remains unchanged during temperature changes.

[0096] It should be noted that the material of the corrugated elastic member 111, the dimensions of each corrugated connecting portion and each corrugated bending portion, and the material of the compensation elastic member 112, the dimensions of each compensation connecting portion and each compensation bending portion can be set by the user according to needs. This application does not limit them, but it must be satisfied that: the compensation elastic member 112 is adapted to the corrugated elastic member 111, and when the temperature changes by the same amount, the expansion and deformation between the two can be exactly offset, thereby achieving temperature self-compensation.

[0097] In a preferred embodiment, the corrugated elastic member 111 and the compensating elastic member 112 can be made of one of manganese-nickel-copper alloy, nickel-chromium-iron alloy, nickel-iron alloy, brass, stainless steel and aluminum alloy.

[0098] In a specific embodiment, if Figure 3As shown, each compensating elastic member 112 is disposed inside each corrugated elastic member 111. The first compensating connection portion 112a, the compensating bent portion 112c, and the second compensating connection portion 112b of each compensating elastic member 112 are respectively abutted against the second corrugated connection portion 111b, the second corrugated bent portion 111e, and the third corrugated connection portion 111c of each corrugated elastic member 111. At this point, the thermal expansion coefficient of each compensating elastic member 112 is greater than that of each corrugated elastic member 111.

[0099] In this embodiment, the method of achieving temperature self-compensation by the compensation elastic member 112 and the corrugated elastic member 111 includes: when the gas temperature of the gas to be measured rises, the gas pressure on the corrugated elastic member 111 and the compensation elastic member 112 attached thereto increases, and the corrugated elastic member 111 and the compensation elastic member 112 are elongated and deformed, but because the thermal expansion coefficient of the compensation elastic member 112 is greater than the thermal expansion coefficient of the corrugated elastic member 111, the elongation deformation of the compensation elastic member 112 is greater than the elongation deformation of the corrugated elastic member 111, and the larger elongation deformation of the compensation elastic member 112 causes the corrugated elastic member 111 to contract, thereby overcoming the elongation deformation of the corrugated elastic member 111; when When the gas temperature of the gas to be measured decreases, the gas pressure on the corrugated elastic member 111 and the compensating elastic member 112 attached thereto decreases, and the corrugated elastic member 111 and the compensating elastic member 112 shrink and deform. However, since the thermal expansion coefficient of the compensating elastic member 112 is greater than the thermal expansion coefficient of the corrugated elastic member 111, the shrinkage deformation of the compensating elastic member 112 is greater than the shrinkage deformation of the corrugated elastic member 111. The larger shrinkage deformation of the compensating elastic member 112 causes the corrugated elastic member 111 to expand, overcoming the shrinkage deformation of the corrugated elastic member 111; therefore, the corrugated elastic member 111 does not expand and contract due to temperature changes, and the corrugated outer tube remains unchanged as a whole when the temperature changes.

[0100] In a specific embodiment, if Figure 4 As shown, each compensating elastic member 112 is disposed on the outside of each corrugated elastic member 111. The first compensating connection portion 112a, the compensating bent portion 112c, and the second compensating connection portion 112b of each compensating elastic member 112 are respectively abutted against the first corrugated connection portion 111a, the first corrugated bent portion 111d, and the second corrugated connection portion 111b of each corrugated elastic member 111. At this point, the thermal expansion coefficient of each compensating elastic member 112 is greater than that of each corrugated elastic member 111.

[0101] In this embodiment, the method of achieving temperature self-compensation by the compensation elastic member 112 and the corrugated elastic member 111 includes: when the gas temperature of the gas to be measured rises, the gas pressure on the corrugated elastic member 111 and the compensation elastic member 112 attached thereto increases, and the corrugated elastic member 111 and the compensation elastic member 112 are elongated and deformed, but because the thermal expansion coefficient of the compensation elastic member 112 is greater than the thermal expansion coefficient of the corrugated elastic member 111, the elongation deformation of the compensation elastic member 112 is greater than the elongation deformation of the corrugated elastic member 111, and the larger elongation deformation of the compensation elastic member 112 causes the corrugated elastic member 111 to contract, overcoming the elongation deformation of the corrugated elastic member 111; when the gas to be measured rises, the gas pressure on the corrugated elastic member 111 and the compensation elastic member 112 attached thereto increases, and the corrugated elastic member 111 and the compensation elastic member 112 are elongated and deformed. As the gas temperature of the measuring gas decreases, the gas pressure on the corrugated elastic member 111 and the compensating elastic member 112 fitted therewith decreases, and the corrugated elastic member 111 and the compensating elastic member 112 shrink and deform. However, since the thermal expansion coefficient of the compensating elastic member 112 is greater than the thermal expansion coefficient of the corrugated elastic member 111, the shrinkage deformation of the compensating elastic member 112 is greater than the shrinkage deformation of the corrugated elastic member 111. The larger shrinkage deformation of the compensating elastic member 112 causes the corrugated elastic member 111 to expand, overcoming the shrinkage deformation of the corrugated elastic member 111. Therefore, the corrugated elastic member 111 does not expand and contract due to temperature changes, and the corrugated outer tube remains unchanged as a whole when the temperature changes.

[0102] In a specific embodiment, if Figure 5 As shown, each compensating elastic member 112 is disposed on the outside of each corrugated elastic member 111. The first compensating connection portion 112a, the compensating bent portion 112c, and the second compensating connection portion 112b of each compensating elastic member 112 are respectively abutted against the second corrugated connection portion 111b, the second corrugated bent portion 111e, and the third corrugated connection portion 111c of each corrugated elastic member 111. At this point, the thermal expansion coefficient of the compensating elastic member 112 is smaller than that of the corrugated elastic member 111.

[0103] In this embodiment, the method of achieving temperature self-compensation by the compensation elastic member 112 and the corrugated elastic member 111 includes: when the gas temperature of the gas to be measured rises, the gas pressure on the corrugated elastic member 111 and the compensation elastic member 112 attached thereto increases, and the corrugated elastic member 111 and the compensation elastic member 112 are elongated and deformed, but because the thermal expansion coefficient of the compensation elastic member 112 is smaller than the thermal expansion coefficient of the corrugated elastic member 111, the elongation deformation of the compensation elastic member 112 is smaller than the elongation deformation of the corrugated elastic member 111, and the smaller elongation deformation of the compensation elastic member 112 causes the corrugated elastic member 111 to contract, thereby overcoming the elongation deformation of the corrugated elastic member 111; when the gas to be measured rises, the gas pressure on the corrugated elastic member 111 and the compensation elastic member 112 attached thereto increases, and the corrugated elastic member 111 and the compensation elastic member 112 are elongated and deformed. As the gas temperature of the measuring gas decreases, the gas pressure on the corrugated elastic member 111 and the compensating elastic member 112 fitted therewith decreases, and the corrugated elastic member 111 and the compensating elastic member 112 shrink and deform. However, since the thermal expansion coefficient of the compensating elastic member 112 is smaller than that of the corrugated elastic member 111, the shrinkage deformation of the compensating elastic member 112 is smaller than that of the corrugated elastic member 111. The smaller shrinkage deformation of the compensating elastic member 112 causes the corrugated elastic member 111 to expand, thereby overcoming the shrinkage deformation of the corrugated elastic member 111. Therefore, the corrugated elastic member 111 does not expand and contract due to temperature changes, and the corrugated outer tube remains unchanged as a whole when the temperature changes.

[0104] It should be noted that, in other embodiments, each of the corrugated elastic members 111 can be fitted with two of the compensating elastic members 112 to form a bimetallic structure, wherein the two compensating elastic members 112 can be respectively disposed on the inner and outer sides of the corrugated elastic member 111, or the compensating bent portions 112c of the two compensating elastic members 112 can be fitted with the first corrugated bent portion 111d and the second corrugated bent portion 111e, respectively. The two compensating elastic members 112 must satisfy the following requirements: the two compensating elastic members 112 are compatible with the corrugated elastic member 111, and when the temperature changes by the same amount, the expansion and deformation between the two compensating elastic members 112 and the corrugated elastic member 111 can be exactly offset, thereby achieving temperature self-compensation.

[0105] like Figure 6 FIG2 is a schematic diagram showing the structure of a self-compensating gas density measuring device according to an embodiment of the present invention. The self-compensating gas density measuring device comprises: a measuring mechanism 1 , a driving mechanism 2 and an indicating mechanism 3 .

[0106] The measuring mechanism 1 includes the self-compensating bellows 11 as described in any of the above embodiments. It should be understood that the specific structure and working principle of the self-compensating bellows 11 have been described in detail in the above embodiments and will not be repeated here for the sake of brevity.

[0107] like Figure 6 as well as Figure 7 As shown, the two ends of the self-compensating bellows 11 are respectively provided with a bellows top cover 12 and a bellows bottom cover 13. Figure 6 As shown, the formed closed air cavity 14 is communicated with the gas to be measured through the air inlet hole 131 on the bellows bottom cover 13 , so that the gas to be measured flows into the closed air cavity 14 .

[0108] And, as Figures 6 to 8 As shown, the bellows top cover 12 is connected to one end of the driving mechanism 2 , and the other end of the driving mechanism 2 is connected to the indicating mechanism 3 .

[0109] In this embodiment, the self-compensating gas density measuring device performs gas density measurement in the following manner: when the gas density of the gas to be measured changes, the self-compensating bellows 11 contracts or stretches under the action of the gas pressure, and drives the driving mechanism 2 to move up and down, thereby driving the indicating mechanism 3 to rotate and indicate the corresponding gas density value; at the same time, when the gas temperature of the gas to be measured changes, the self-compensating bellows 11 undergoes a deformation amount different from that of each corrugated elastic member 111 through each compensating elastic member 112 to overcome the influence of temperature on the deformation of each corrugated elastic member 111, so that the self-compensating bellows 11 remains unchanged, and thereby the driving mechanism 2 and the indicating mechanism 3 remain unchanged.

[0110] In one embodiment, if Figures 6 to 8 As shown, the drive mechanism 2 includes a guide rod 21 and a slider 23. One end of the guide rod 21 is connected to the bellows cover 12 via a cylindrical pin 22. When the self-compensating bellows 11 contracts or extends, it drives the bellows cover 12 up and down, thereby driving the guide rod 21 up and down. The slider 23 is fixedly connected to the other end of the guide rod 21. When the self-compensating bellows 11 contracts or extends, the slider 23 moves up and down with the guide rod 21. The slider 23 is provided with a first guide groove 231, which is connected to the indicating mechanism 3. When the slider 23 moves up and down, it drives the indicating mechanism 3 to rotate and indicate the corresponding gas density value.

[0111] In one embodiment, if Figure 6 As shown, the indicating mechanism 3 includes: a movement 31 , a pointer 32 and a dial 33 .

[0112] like Figure 7As shown, the movement 31 includes a sector tooth 311 and a pointer shaft 313 meshingly connected to one end of the sector tooth 311 via a gear structure 312. A second guide groove 314 is provided at the other end of the sector tooth 311. A first connecting member 34 passes through the second guide groove 314 and the first guide groove 231 of the slider 23 to connect the sector tooth 311 and the slider 23.

[0113] like Figure 7 As shown, one end of the pointer 32 is connected to the pointer shaft 313. Figure 6 As shown, the dial 33 is arranged between the movement 31 and the pointer 32, and the side of the dial facing the pointer 32 is marked with a scale of gas density values.

[0114] In this embodiment, when the slider 23 moves up and down, it drives the sector teeth 311 to rotate, and drives the pointer shaft 313 to rotate through the gear structure 312, thereby driving the pointer 32 to rotate around the connection point with the pointer shaft 313. After the pointer 32 rotates and aligns with the scale marked on the dial 33, it indicates the gas density value of the gas to be measured.

[0115] In a specific embodiment, if Figure 9 As shown, the movement 31 further includes a first support plate 315 and a second support plate 316, respectively disposed on either side of the sector teeth 311. The first and second support plates 315, 316 are connected via one or more first fixing posts 317 and are connected to the sector teeth 311 via second fixing posts 318, thereby supporting the sector teeth 311. The movement 31 further includes a hairspring 319. The hairspring 319 is disposed on the gear structure 312 and connected to the pointer shaft 313 via the gear structure 312. When the sector teeth 311 rotate, the gear structure 312, the pointer shaft 313, and the pointer 32 rotate. The hairspring 319 generates a reaction torque to eliminate pointer instability caused by gaps between the gear structure 312 and the sector teeth 311, as well as gaps at the junction of the drive mechanism 2 and the indicating mechanism 3. This ensures accurate and stable indication by the pointer 32 and helps the pointer 32 quickly return to zero after the gas pressure is eliminated.

[0116] In one embodiment, if Figure 6 as well as Figure 8 As shown, the self-compensating gas density measuring device further includes a support mechanism 4. The support mechanism 4 is used to fix and support various components of the self-compensating gas density measuring device. Specifically, the support mechanism 4 includes an outer cylinder 41, a cylinder cover 43, and an L-shaped support frame 44.

[0117] like Figure 6 as well as Figure 8 As shown, the outer cylinder 41 is provided outside the self-compensating bellows 11, and an air inlet portion 42 is provided at its lower end. The air inlet portion 42 is provided with an air inlet channel 421. The air inlet portion 42 is fixedly connected to the bottom cover 13 of the bellows and is connected to the measuring air pipe for storing the gas to be measured, so that the air inlet channel 421 is connected to the closed air cavity 14 and the gas to be measured, respectively. As a result, the gas to be measured in the measuring air pipe enters the closed air cavity 14 through the air inlet channel 421 and the air inlet hole 131, so that the closed air cavity 14 is filled with the gas to be measured. When the gas density of the gas to be measured changes, the gas pressure in the closed air cavity 14 changes synchronously. The self-compensating gas density measuring device can measure and monitor the change in the gas density of the gas to be measured based on the change in the gas density in the closed air cavity 14.

[0118] like Figure 8 As shown, the cylinder cover 43 is mounted on the upper end of the outer cylinder 41, and one or more support columns 431 are disposed on the top of the cylinder cover 43. The L-shaped support frame 44 includes a first support portion 441 and a second support portion 442 disposed perpendicular to the first support portion 441. The first support portion 441 is fixedly connected to each of the support columns 431, and the second support portion 442 is fixedly connected to the dial 33 via one or more second connectors 45.

[0119] In a specific embodiment, the self-compensating gas density measuring device performs gas density measurement in the following manner: when the gas density of the gas to be measured changes, the self-compensating bellows 11 contracts or extends under the action of the gas pressure, driving the bellows top cover 12, the cylindrical pin 22, the guide rod 21 and the slider 23 to move up and down in turn, thereby driving the sector teeth 311 to rotate, and driving the pointer shaft 313 to rotate through the gear structure 312, and then driving the pointer 32 to rotate with the connection point with the pointer shaft 313 as the center. After the pointer 32 rotates and aligns with the scale marked on the dial 33, it indicates the gas density value of the gas to be measured. Since the self-compensating bellows 11 has a temperature self-compensation function, even when the gas temperature changes, the multiple compensating elastic members 112 therein undergo deformation amounts different from those of the corrugated elastic members 111, which can overcome the influence of temperature on the deformation of the corrugated elastic members 111, so that the self-compensating bellows 11 does not expand and contract due to temperature changes, and thus the pointer 32 always indicates the gas density value at the specified temperature, thereby ensuring the accuracy of the gas density measurement performed by the self-compensating gas density measuring device.

[0120] The purpose of this design in this embodiment is to improve the structure of the bellows itself and add a compensating spring member to the bellows, giving it a bimetallic structure that can self-compensate for temperature changes. As a result, the self-compensating gas density measurement device eliminates the need for additional gas compensation or bimetallic compensation components, saving significant structural complexity. Furthermore, the product process is simple, significantly reducing costs and making it more suitable for mass production.

[0121] It should be noted that, in one embodiment, the self-compensating gas density measuring device may also be provided with a micro switch and a remote transmission mechanism.

[0122] The micro switch is a switch with a small contact spacing and a quick-action mechanism. In the self-compensating gas density measuring device, when the expansion and contraction deformation of the self-compensating bellows 11 due to the change in gas density reaches a preset value, the micro switch will be pushed, causing the normally open node or the normally closed node of the micro switch to quickly operate to realize the on and off of the circuit, thereby providing a node signal to feedback the working status of the self-compensating gas density measuring device and transmit the gas density change of the gas to be measured to an external monitoring system or other related equipment.

[0123] Specifically, under normal circumstances, the normally open node of the microswitch is in an open state, and the normally closed node is in a closed state. When the self-compensating gas density measuring device detects that the gas density is lower than or higher than a preset normal operating range, the microswitch is actuated, closing the normally open node or disconnecting the normally closed node, and sending an alarm signal to an external monitoring system or other related equipment. When the gas density is seriously abnormal, such as when the gas density is detected to be lower than or higher than the preset alarm range, a serious abnormality node signal is sent to cut off the power supply of the self-compensating gas density measuring device through the relevant control device, causing the self-compensating gas density measuring device to stop operating and realize the locking function. This prevents equipment failure or accidents caused by gas density problems and protects the safety of equipment and personnel.

[0124] The remote transmission mechanism includes multiple types of sensors to provide remote transmission signals, so that the staff can timely grasp the operating status of the self-compensating gas density measuring device. The sensors include but are not limited to: temperature sensors, humidity sensors and pressure sensors, etc., which are respectively used to monitor the gas parameters such as gas temperature, humidity and pressure in the self-compensating gas density measuring device in real time. When each sensor detects that the gas parameters deviate from the normal range, the remote transmission mechanism sends a remote transmission signal to the external monitoring system or other related equipment to provide timely warnings to the staff, reminding them to check and handle the problem as soon as possible to avoid equipment failure or accidents due to abnormal gas parameters. In addition, the external monitoring system can also store, analyze and count the gas parameters obtained by remote transmission. By analyzing the changing trends of gas parameters, etc., it can evaluate the health status of the equipment, provide a basis for equipment maintenance and inspection, and realize refined management of the equipment.

[0125] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

[0126] In summary, the present application provides a self-compensating bellows, which is provided with a plurality of compensating elastic members that fit together with the plurality of corrugated elastic members of the corrugated outer tube, and the thermal expansion coefficients of the compensating elastic members and the corrugated elastic members are inconsistent, so that when the temperature of the gas in the self-compensating bellows changes, each compensating elastic member undergoes a deformation amount different from that of each corrugated elastic member, so as to overcome the influence of temperature on the deformation of each corrugated elastic member, thereby enabling the self-compensating bellows to achieve temperature self-compensation. The present application provides a self-compensating gas density measuring device, which uses the self-compensating bellows as a measuring mechanism, so that the device does not need to install additional temperature compensation elements such as a compensating gas chamber or a bimetallic strip, thereby having the following beneficial effects: simplifying the structure of the self-compensating gas density measuring device and reducing costs, solving the technical problems of the complex structure and high cost of the temperature compensation method of the existing gas density measuring equipment; at the same time, the product process is simple and more suitable for batch production operations.

[0127] Therefore, the present invention effectively overcomes various shortcomings of the prior art and has high industrial utilization value.

[0128] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical concepts disclosed in this application shall be covered by the claims of this application.

Claims

1. A self-compensating bellows, characterized in that: include: A corrugated outer tube, the corrugated outer tube being a corrugated shell including a plurality of corrugated elastic members (111); A plurality of compensating elastic members (112), each compensating elastic member (112) being connected to the corrugated outer tube and being fitted with each corrugated elastic member (111); The corrugated elastic member (111) comprises: a first corrugated connecting portion (111a), a second corrugated connecting portion (111b), a third corrugated connecting portion (111c), a first corrugated bending portion (111d), and a second corrugated bending portion (111e); two ends of the first corrugated bending portion (111d) are respectively connected to one end of the first corrugated connecting portion (111a) and one end of the second corrugated connecting portion (111b); two ends of the second corrugated bending portion (111e) are respectively connected to the other end of the second corrugated connecting portion (111b) and one end of the third corrugated connecting portion (111c); The compensating elastic member (112) comprises: a first compensating connecting portion (112a), a second compensating connecting portion (112b), and a compensating bending portion (112c); two ends of the compensating bending portion (112c) are respectively connected to one end of the first compensating connecting portion (112a) and one end of the second compensating connecting portion (112b); When the gas density in the self-compensating bellows changes, the angle between each bellows connecting portion and each bellows bending portion changes, and each bellows elastic member (111) deforms under the action of gas pressure, driving the entire bellows outer tube to extend or contract; The thermal expansion coefficients of the compensation elastic member (112) and the corrugated elastic member (111) are inconsistent. When the temperature of the gas in the self-compensating bellows changes, the angle between each corrugated connection portion and each corrugated bending portion changes, and the angle between each compensation connection portion and each compensation bending portion changes. Each compensation elastic member (112) undergoes a different deformation amount from that of each corrugated elastic member (111), thereby overcoming the influence of temperature on the deformation of each corrugated elastic member (111), thereby keeping the overall corrugated outer tube unchanged.

2. The self-compensating bellows according to claim 1, characterized in that: Each compensation elastic member (112) is respectively arranged on the inner side of each corrugated elastic member (111); wherein the first compensation connection portion (112a), the compensation bending portion (112c), and the second compensation connection portion (112b) of each compensation elastic member (112) are respectively fitted with the first corrugated connection portion (111a), the first corrugated bending portion (111d), and the second corrugated connection portion (111b) of each corrugated elastic member (111); and the thermal expansion coefficient of the compensation elastic member (112) is smaller than the thermal expansion coefficient of the corrugated elastic member (111).

3. The self-compensating bellows according to claim 1, characterized in that: Each compensation elastic member (112) is respectively arranged on the inner side of each corrugated elastic member (111); wherein the first compensation connection portion (112a), the compensation bending portion (112c) and the second compensation connection portion (112b) of each compensation elastic member (112) are respectively fitted with the second corrugated connection portion (111b), the second corrugated bending portion (111e) and the third corrugated connection portion (111c) of each corrugated elastic member (111); the thermal expansion coefficient of the compensation elastic member (112) is greater than the thermal expansion coefficient of the corrugated elastic member (111).

4. The self-compensating bellows according to claim 1, characterized in that: Each compensation elastic member (112) is respectively arranged on the outside of each corrugated elastic member (111); wherein the first compensation connection portion (112a), the compensation bending portion (112c), and the second compensation connection portion (112b) of each compensation elastic member (112) are respectively fitted with the first corrugated connection portion (111a), the first corrugated bending portion (111d), and the second corrugated connection portion (111b) of each corrugated elastic member (111); and the thermal expansion coefficient of the compensation elastic member (112) is greater than the thermal expansion coefficient of the corrugated elastic member (111).

5. The self-compensating bellows according to claim 1, characterized in that: Each compensation elastic member (112) is respectively arranged on the outside of each corrugated elastic member (111); wherein the first compensation connection portion (112a), the compensation bending portion (112c), and the second compensation connection portion (112b) of each compensation elastic member (112) are respectively fitted with the second corrugated connection portion (111b), the second corrugated bending portion (111e), and the third corrugated connection portion (111c) of each corrugated elastic member (111); and the thermal expansion coefficient of the compensation elastic member (112) is smaller than the thermal expansion coefficient of the corrugated elastic member (111).

6. A self-compensating gas density measuring device, characterized in that: include: A measuring mechanism (1), comprising: a self-compensating bellows (11) according to any one of claims 1 to 5; a bellows top cover (12) and a bellows bottom cover (13) are respectively provided at both ends of the self-compensating bellows (11), and a closed air cavity (14) formed therein is communicated with a gas to be measured through an air inlet hole (131) on the bellows bottom cover (13), so that the gas to be measured flows into the closed air cavity (14); the bellows top cover (12) is connected to one end of a driving mechanism (2), and the other end of the driving mechanism (2) is connected to an indicating mechanism (3); When the gas density of the gas to be measured changes, the self-compensating bellows (11) contracts or extends under the action of the gas pressure, and drives the driving mechanism (2) to move up and down, thereby driving the indicating mechanism (3) to rotate and indicate the corresponding gas density value; When the gas temperature of the gas to be measured changes, the self-compensating bellows (11) undergoes deformation different from that of the respective corrugated elastic members (111) through the respective compensating elastic members (112) to overcome the influence of the temperature on the deformation of the respective corrugated elastic members (111), thereby keeping the self-compensating bellows (11) unchanged, and further keeping the driving mechanism (2) and the indicating mechanism (3) unchanged.

7. The self-compensating gas density measuring device according to claim 6, characterized in that: The driving mechanism (2) comprises: A guide rod (21), one end of which is connected to the bellows top cover (12) via a cylindrical pin (22); when the self-compensating bellows (11) contracts or extends, it drives the bellows top cover (12) to move up and down, thereby driving the guide rod (21) to move up and down; A slider (23) is fixedly connected to the other end of the guide rod (21). When the self-compensating bellows (11) contracts or extends, the slider (23) moves up and down following the guide rod (21). A first guide groove (231) is provided on the slider (23) and is connected to the indicating mechanism (3). When the slider (23) moves up and down, it drives the indicating mechanism (3) to rotate and indicates the corresponding gas density value.

8. The self-compensating gas density measuring device according to claim 7, characterized in that: The indicating mechanism (3) comprises: The movement (31) comprises: a sector tooth (311) and a pointer shaft (313) meshingly connected to one end of the sector tooth (311) via a gear structure (312); a second guide groove (314) is provided at the other end of the sector tooth (311); a first connecting member (34) passes through the second guide groove (314) and the first guide groove (231) of the slider (23) to connect the sector tooth (311) and the slider (23); A pointer (32), one end of the pointer (32) is connected to the pointer shaft (313); A dial (33), the dial (33) being arranged between the movement (31) and the pointer (32), and having a scale indicating a gas density value on a side thereof facing the pointer (32); When the slider (23) moves up and down, it drives the sector teeth (311) to rotate, and drives the pointer shaft (313) to rotate through the gear structure (312), thereby driving the pointer (32) to rotate around the connection point with the pointer shaft (313). After the pointer (32) rotates and aligns with the scale marked on the dial (33), it indicates the gas density value of the gas to be measured.

9. The self-compensating gas density measuring device according to claim 8, characterized in that: Also includes: Support mechanism (4); Wherein, the support mechanism (4) comprises: An outer cylinder (41) is provided outside the self-compensating bellows (11); an air inlet portion (42) is provided at the lower end of the outer cylinder (41), and the air inlet portion (42) is provided with an air inlet channel (421); the air inlet portion (42) is fixedly connected to the bellows bottom cover (13), and is connected to a measuring air pipe for storing the gas to be measured, so that the air inlet channel (421) is respectively connected to the closed air cavity (14) and the gas to be measured; when the gas density of the gas to be measured changes, the gas pressure in the closed air cavity (14) changes; A cylinder cover (43) is provided at the upper end of the outer cylinder (41), and one or more supporting columns (431) are provided on the top of the cylinder cover (43); The L-shaped support frame (44) comprises: a first support portion (441) and a second support portion (442) arranged perpendicular to the first support portion (441); the first support portion (441) is fixedly connected to each of the support columns (431), and the second support portion (442) is fixedly connected to the dial (33) via one or more second connecting members (45).

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