Gas density relay and manufacturing method therefor

Abstract

The present invention relates to a gas density relay and a manufacturing method therefor. A gas channel is provided in a base, a Bourdon tube is mounted on the base, and an inner cavity of the Bourdon tube is in communication with the gas channel; a second chamber of a contact apparatus is also in communication with the gas channel, the second chamber is in communication with a filling connector, and the filling connector is configured to be connected to a gas chamber of an electrical device, so that an insulating gas in the gas chamber of the electrical device can be filled in the contact apparatus and the Bourdon tube of a display apparatus by means of the filling connector and the gas channel in the base. The gas channel directly realizes gas-path communication, eliminating the need for a metal capillary tube, thereby avoiding fracture of the metal capillary tube caused by vibration during assembly or use. In addition, since a first chamber and a second chamber of the display apparatus are not communicated in the gas path and are isolated from each other, a compensating gas or oil can be filled in the first chamber of the display apparatus to overcome the impact of factors such as altitude or vibration on display precision.

Description

A gas density relay and its manufacturing method Technical Field

[0001] This invention relates to a gas density relay and its manufacturing method, and particularly to a manufacturing method for a gas density relay with good vibration resistance. Background Technology

[0002] In recent years, with the rapid development of my country's economy, SF6 (sulfur hexafluoride) electrical equipment has been widely used in the power sector and industrial and mining enterprises, promoting the rapid development of the power industry. SF6 gas density relays are one of the key components of SF6 electrical equipment. They are used to detect changes in the density of SF6 gas within the equipment, and their performance directly affects the reliable and safe operation of the equipment. The industry commonly uses mechanical pointer-type SF6 gas density relays to monitor SF6 gas density. When a leak occurs in the SF6 electrical equipment, the density relay can output alarm and interlocking signals to ensure the safe operation of the equipment. Currently, a widely used density relay uses a C-tube (also known as a Baden tube) as the pressure-sensing element in its display section and a bimetallic strip as the compensation element; its contact section uses a bellows as the pressure-sensing element and a relative cavity as the compensation element. The aforementioned density relay contacts possess excellent electrical performance, and the relative cavity compensation method provides ideal vibration resistance. However, because the air circuit connection between the Baden tube of the display device and the gas filling connector uses a capillary structure, capillary breakage is easily caused during assembly and field application, leading to gas leakage, triggering alarm and interlocking signals, and compromising the effective and reliable operation of the system. This is especially true for some SF6 circuit breakers, which often generate significant impact forces during opening / closing operations. In short, its vibration resistance is not ideal, making it difficult to guarantee the reliable operation of the power grid system. To reduce capillary breakage, the industry generally uses limit protection for the capillary, but this cannot completely solve the problem and also introduces risks such as increased product structure complexity and weight.

[0003] To overcome the problem of capillary tube breakage in the gas path connecting the display section's main gas chamber, the contact section's main gas chamber, and the electrical equipment's gas chamber during the opening / closing operation of electrical switches in field environments using SF6 gas density relays, there is an urgent need for a highly vibration-resistant gas density relay and its manufacturing method. This relay can be applied to the ubiquitous power Internet of Things SF6 gas density monitoring system to improve efficiency and ensure safety. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a gas density relay and its manufacturing method, which avoids the risk of capillary breakage due to vibration and other reasons, and has good vibration resistance.

[0005] To achieve the above objectives, the present invention provides a gas density relay, comprising a display device, a contact device, and an inflation connector. The display device has a first chamber, in which a base, a Baden tube, and a pointer mechanism are disposed. One end of the Baden tube is fixed to the base, and the other end of the Baden tube is drively connected to the pointer mechanism. The base has an air passage, and the inner cavity of the Baden tube communicates with the air passage. The contact device has a second chamber, which communicates with the inflation connector. The air passage communicates with the second chamber. The second chamber has a bellows and a micro switch. The inner cavity of the bellows is sealed with pre-charged gas. One end of the bellows is sealed and fixed, and the other end of the bellows is connected to a push rod for triggering the micro switch.

[0006] Preferably, the display device includes a protective cover, a transparent cover, and an end cap. The protective cover is fitted over the outside of the transparent cover. The front end of the protective cover has an observation window, and the front end of the transparent cover faces the observation window. The opening at the rear end of the transparent cover is sealed by the end cap. The space between the transparent cover and the end cap forms the first chamber. The end cap has a connection hole, and the base has a connector. The air inlet of the air passage is located at the end of the connector. The connector is inserted into the connection hole, and the connector and the connection hole are sealed together.

[0007] More preferably, the contact device has a sealing shell, the inner cavity of which is the second chamber, and the sealing shell has a forward-protruding insertion tube, into which the connector is inserted, and the connector and the insertion tube are sealed together.

[0008] Furthermore, a sealing ring is provided between the connector and the connecting hole, and one or two sealing rings are provided between the connector and the insertion tube.

[0009] Furthermore, the end cap has a pressure plate at its rear end, which presses against the end cap; or the end cap has an intermediate housing at its rear end, which presses against the end cap.

[0010] Furthermore, the sealing shell and protective cover have a cylindrical structure.

[0011] Furthermore, the inflation connector is connected to the sealing shell, and the sealing shell is also provided with a cable connector.

[0012] Preferably, the end cap is further provided with a filling inlet, which is sealed by a threaded plug.

[0013] Preferably, the end cap and the transparent cover are sealed by a sealing ring.

[0014] Corresponding to the gas density relay of the present invention described above, the present invention also provides a method for manufacturing a gas density relay, for manufacturing the gas density relay described in the above technical solution, comprising the following steps:

[0015] 1) Assemble the base, Baden tube, and pointer mechanism together, and then connect the connector of the base to the connection hole of the end cap;

[0016] 2) Install a transparent cover on the end cap, thereby enclosing the base, Baden tube, and pointer mechanism in the first chamber between the end cap and the transparent cover;

[0017] 3) Fill the first chamber with gas or oil at standard atmospheric pressure through the filling inlet, and then seal the filling inlet with a threaded plug;

[0018] 4) Put a protective cover on the outside of the transparent cover, and install a pressure plate at the rear end of the end cover to press the end cover tightly, or install an intermediate shell at the rear end of the end cover to press the end cover tightly.

[0019] 5) Install the bellows, micro switch and inflation connector together with the sealing shell, and then insert the connector of the base into the insertion tube of the sealing shell, and seal the connection between the connector and the insertion tube.

[0020] As described above, the gas density relay and its manufacturing method according to the present invention have the following beneficial effects: In the gas density relay of the present invention, since a gas channel is provided in the base, the Baden tube is installed on the base and the inner cavity of the Baden tube is connected to the gas channel; the second chamber of the contact device is also connected to the gas channel, and the second chamber is connected to the inflation connector, which is used to connect to the gas chamber of the electrical equipment. In this way, the insulating gas in the gas chamber of the electrical equipment can be filled into the contact device and the Baden tube of the display device through the inflation connector and the gas channel in the base. The gas channel directly realizes the gas path connection, eliminating the need for a metal capillary tube, thereby avoiding the breakage of the metal capillary tube due to vibration during assembly or use. In addition, since the first chamber and the second chamber of the display device are not connected in the gas path and are isolated from each other, compensating gas or oil can be filled into the first chamber of the display device to overcome the influence of factors such as altitude or vibration on the display accuracy.

[0021] The manufacturing method of the gas density relay of the present invention also has the above-mentioned beneficial effects, which will not be repeated here. Attached Figure Description

[0022] Figure 1 shows a cross-sectional structural diagram of a first embodiment of the gas density relay of the present invention.

[0023] Figure 2 shows a perspective cross-sectional view of the display device of the gas density relay of the present invention.

[0024] Figure 3 shows a cross-sectional structural diagram of a second embodiment of the gas density relay of the present invention.

[0025] Figure 4 shows a cross-sectional view of a third embodiment of the gas density relay of the present invention.

[0026] Figure 5 shows a perspective structural diagram of a third embodiment of the gas density relay of the present invention.

[0027] Figure 6 shows a schematic diagram of the control module connection of the intelligent control component.

[0028] Component designation explanation

[0029] 1. Display device 2. Contact device 3. Inflation connector 4. First chamber 5. Base 6. Baden tube 7. Pointer mechanism 8. Air passage 9. Second chamber 10. Bellows 11. Micro switch 12. Push rod 13. Protective cover 14. Transparent cover 15. End cap 16. Observation window 17. Connection hole 18. Connector 19. Sealing shell 20. Insert pipe 21. Sealing ring 22. Pressure plate 23. Cable connector 24. Inflation inlet 25. Threaded plug 26. Glass plate 27. Fixing screw 28. Intelligent control component 29. Intermediate shell 30. Rear shell 31. Annular positioning groove 32. Annular insert connector 33. Sealing groove Detailed Implementation

[0030] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0031] It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings of this specification are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of the invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0032] As shown in Figures 1, 3, and 4, the present invention provides a gas density relay, including a display device 1, a contact device 2, and an inflation connector 3. The display device 1 has a first chamber 4, in which a base 5, a Baden tube 6, and a pointer mechanism 7 are provided. One end of the Baden tube 6 is fixed to the base 5, and the other end of the Baden tube 6 is connected to the pointer mechanism 7. The base 5 has an air passage 8, and the inner cavity of the Baden tube 6 communicates with the air passage 8. The contact device 2 has a second chamber 9, which communicates with the inflation connector 3. The air passage 8 communicates with the second chamber 9. The second chamber 9 has a bellows 10 and a micro switch 11. The inner cavity of the bellows 10 is sealed with pre-charged gas. One end of the bellows 10 is sealed and fixed, and the other end of the bellows 10 is connected to a push rod 12 for triggering the micro switch 11.

[0033] The operation of a gas density relay according to the present invention is as follows: Referring to Figures 1, 3, and 4, the inflation connector 3 is connected to the insulating gas chamber of the electrical equipment. The second chamber 9 of the contact device 2 is sealed into a gas-sealed cavity. The gas in the insulating gas chamber of the electrical equipment enters the second chamber 9 of the contact device 2 through the inflation connector 3. The second chamber 9 is directly connected to the gas channel 8 on the base 5. Therefore, the gas in the gas channel 8 has the same density as the gas in the insulating gas chamber of the electrical equipment. The gas in the gas channel 8 enters the Baden tube 6. Referring to Figures 1 and 2, the Baden tube 6, as a detection element, will undergo precise deformation according to the gas pressure or density in its inner cavity, thereby driving the pointer mechanism 7 to indicate an accurate density value. The first chamber 4 is completely sealed and is neither connected to the Baden tube 6 nor to the second chamber 9. As needed, the first chamber 4 can be filled with gas at standard atmospheric pressure so that the Baden tube 6 and the pointer assembly can remain under standard atmospheric pressure in high-altitude environments, thereby avoiding the influence of high-altitude environments on the indication accuracy. Alternatively, the first chamber 4 can be filled with oil to prevent vibration from affecting the pointer indication. To facilitate the filling of gas or oil into the first chamber 4, as shown in Figure 1, a filling inlet 24 is provided on the end cap 15, which is sealed by a threaded plug 25. Gas or oil can be filled through the filling inlet 24, and after filling, the filling inlet 24 is sealed with the threaded plug 25. The bellows 10 is pre-filled with compensating gas, which can be selected as needed to compensate for environmental factors such as temperature, so that the contact device 2 can more accurately measure the gas density in the insulating gas chamber of the electrical equipment.

[0034] In a gas density relay of the present invention, an air passage 8 is provided in the base 5, and a Baden tube 6 is installed on the base 5 with its inner cavity connected to the air passage 8. The second chamber 9 of the contact device 2 is also connected to the air passage 8 and to the inflation connector 3. The inflation connector 3 is used to connect to the air chamber of the electrical equipment. In this way, the insulating gas in the air chamber of the electrical equipment can be filled into the Baden tube 6 of the display device 1 through the inflation connector 3 and the air passage 8 in the base 5. The air passage 8 directly realizes the air path connection, eliminating the need for a metal capillary tube and thus avoiding the breakage of the metal capillary tube due to vibration during assembly or use. In addition, since the first chamber 4 and the second chamber 9 of the display device 1 are not connected in the air path and are isolated from each other, compensating gas or oil can be filled into the first chamber 4 of the display device 1 to overcome the influence of factors such as altitude or vibration on the display accuracy.

[0035] In a gas density relay of the present invention, the gas in the insulating gas chamber of the electrical equipment enters the second chamber 9, the gas passage 8 of the base 5, and the Baden tube 6 through the gas filling connector 3. The Baden tube 6 deforms according to the gas density (density is related to pressure) and drives the pointer mechanism 7 to indicate the gas density. The bellows 10 in the second chamber 9 deforms according to the gas density in the second chamber 9 and the pre-filled gas density in the bellows 10 and drives the top rod 12 to produce a corresponding displacement, thereby triggering the opening and closing of the micro switch 11. The micro switch 11 generates an electrical signal and transmits it to the intelligent control unit for processing.

[0036] In a gas density relay of the present invention, the gas in the insulating gas chamber of the electrical equipment enters the second chamber 9 through the inflation connector 3. The lower end of the sealing shell 19 is sealed by the lower bottom plate of the bellows, which forms the bottom of the sealing shell 19. The inflation connector 3 is connected to the sealing shell 19 (refer to Figure 4). The intermediate shell 29 and the rear shell 30 are also provided with cable connectors 23 and junction boxes for connecting the micro switch 11 and the electrical components in the intelligent unit.

[0037] Example 1:

[0038] As shown in Figure 1, the display device 1 includes a protective cover 13, a transparent cover 14, and an end cap 15. The protective cover 13 is fitted over the transparent cover 14. The front end of the protective cover 13 has an observation window 16. The front end of the transparent cover 14 faces the observation window 16. The opening at the rear end of the transparent cover 14 is sealed by the end cap 15. The space between the transparent cover 14 and the end cap 15 forms a first chamber 4. The end cap 15 is provided with a connection hole 17. The base 5 has a connector 18. The air inlet of the air passage 8 is located at the end of the connector 18. The connector 18 is inserted into the connection hole 17. The connector 18 and the connection hole 17 are sealed together. Thus, the base 5 is fixedly installed on the end cap 15. The Baden tube 6 is sealed and fixedly installed on the base 5. One end of the Baden tube 6 is connected to the air passage 8 on the base 5. A glass plate 26 is also provided at the front end of the protective cover 13. The glass plate 26 is located between the inwardly extending edge of the observation window 16 and the transparent cover 14. The front end of the transparent cover 14 rests on the glass plate 26, and the glass plate 26 presses against the inwardly extending edge of the observation window 16. A sealing ring 21 is provided between the glass plate 26 and the front end face of the transparent cover 14. The sealing ring 21 can prevent water vapor from entering between the front end face of the transparent cover 14 and the glass plate 26 and causing condensation. As mentioned earlier, the space between the transparent cover 14 and the end cap 15 forms the first chamber 4. In order to reliably seal the space between the end cap 15 and the transparent cover 14, the end cap 15 and the transparent cover 14 are sealed by the sealing ring 21. The end cap 15 is machined from a relatively thick metal plate. A sealing groove 33 is provided on the front side wall of the end cap 15, and the sealing ring 21 is provided in the sealing groove 33. The transparent cover 14 presses the sealing ring 21 tightly.

[0039] As shown in Figure 1, the contact device 2 has a sealing shell 19, the inner cavity of which is a second chamber 9. The sealing shell 19 has a forward-protruding insertion tube 20, and the connector 18 is inserted into the insertion tube 20. The connector 18 and the insertion tube 20 are sealed together, thus isolating the second chamber 9 from the first chamber 4 and preventing gas communication. To achieve a reliable sealing effect, a sealing ring 21 is provided between the connector 18 and the connection hole 17, and one or two sealing rings 21 are provided between the connector 18 and the insertion tube 20. In Figure 1, the connector 18 on the base 5 is close to the outer side of the end cap 15, thus the connector 18 is close to the air inlet of the Baden tube 6.

[0040] In order to make the end cap 15 press against the transparent cover 14, thereby making the transparent cover 14 press against the glass plate 26 and the sealing cavity between the transparent cover 14 and the glass plate 26, a pressure plate 22 is provided at the rear end of the end cap 15. The pressure plate 22 presses against the end cap 15, and the edge of the pressure plate 22 is fixed to the inner wall of the protective cover 13. The sealing shell 19 is fixed to the pressure plate 22.

[0041] To ensure a reliable seal between the transparent cover 14 and the end cap 15, as shown in Figure 1, an annular positioning groove 31 is provided on the front side of the end cap 15. A sealing groove 33 is provided on the inner wall of the annular positioning groove 31 of the end cap 15, and a sealing ring 21 is provided in the sealing groove 33. An annular connector 32 is provided at the rear end of the transparent cover 14. The annular connector 32 is inserted into the positioning groove. In this way, the annular connector 32 is confined in the positioning groove, and the annular connector 32 and its surrounding parts are not easily deformed. Since the sealing groove 33 is very close to the annular connector 32, the part of the sealing ring 21 that is in sealing contact with the transparent cover 14 is also not easily deformed, resulting in good sealing performance.

[0042] Corresponding to the gas density relay of the present invention described above, the present invention also provides a method for manufacturing a gas density relay, for manufacturing the gas density relay described in the above technical solution, comprising the following steps:

[0043] 1) Assemble the base 5, the Baden tube 6 and the pointer mechanism 7 together, and then connect the connector 18 of the base 5 to the connector hole 17 of the end cap 15;

[0044] 2) Install a transparent cover 14 on the end cap 15, thereby covering the base 5, the Baden tube 6 and the pointer mechanism 7 in the first chamber 4 between the end cap 15 and the transparent cover 14;

[0045] 3) Fill the first chamber 4 with gas or oil at standard atmospheric pressure through the filling inlet 24, and then seal the filling inlet 24 with the threaded plug 25;

[0046] 4) Cover the outside of the transparent cover 14 with the protective cover 13, and install the pressure plate 22 at the rear end of the end cover 15 to press the end cover 15 tightly.

[0047] 5) Install the bellows 10, micro switch 11 and inflation connector 3 together with the sealing shell 19, and then insert the connector 18 of the base 5 into the insertion tube 20 of the sealing shell 19. The connector 18 and the insertion tube 20 are sealed together, which can fix the sealing shell 19 on the pressure plate 22.

[0048] Preferably, step 4) further includes the step of installing a sealing ring 21 and a glass plate 26 on the front end face of the transparent cover 14.

[0049] More specifically, the manufacturing method of a gas density relay according to the present invention mainly consists of the following steps:

[0050] Pre-assemble the Baden tube, pointer mechanism, and base:

[0051] In a dust-free and dry environment, first clean the base 5 thoroughly, ensuring its surface is free of impurities, oil stains, and other contaminants that could affect assembly accuracy. Using high-precision tooling, precisely install the Baden tube 6 in the preset position on the base 5, and tighten it with specialized fasteners such as small bolts and nuts to ensure the stability of the Baden tube 6. Next, install the pointer mechanism 7 and adjust the connection position between the pointer mechanism 7 and the Baden tube 6 to ensure precise linkage between the two. After completing the above assembly, use high-precision measuring tools to measure the dimensions of the connector 18 on the base 5, ensuring it meets the tolerance requirements for mating with the connection hole 17 on the end cap 15. Then, slowly and precisely connect the connector 18 into the connection hole 17. The Baden tube 6 is an elastic element sensitive to pressure changes; its shape changes with changes in internal pressure. Installing it on the base 5 provides a basis for subsequent sensing of gas or oil pressure changes. The pointer mechanism 7 is connected to the Baden tube 6 to convert the deformation of the Baden tube 6 into the rotation of the pointer, thus visually displaying pressure-related information. The connection between the connector 18 and the connecting hole 17 establishes the physical connection foundation between subsequent components. Through precise assembly and connection, the relative positional accuracy between the Baden tube 6, the pointer mechanism 7, and the base 5 is ensured, laying the foundation for accurate measurement and display of pressure information. Simultaneously, the stable connection ensures the reliability of the entire structure.

[0052] A transparent cover is installed to form the first chamber:

[0053] Before installing the transparent cover 14, apply a layer of high-performance silicone sealant evenly to the sealing groove of the end cap 15. Then, carefully align the transparent cover 14 with the end cap 15 and slowly lower it, ensuring a perfect fit between the two, forming a first chamber 4 between the transparent cover 14 and the end cap 15. During installation, use a dedicated positioning tool to ensure a uniform gap between the transparent cover 14 and the end cap 15, avoiding any gaps in sealing. Perform a preliminary sealing test, such as using a helium mass spectrometer leak detector to test the first chamber 4. The first chamber 4 is formed to isolate the internal sensitive components from the external environment, preventing external dust, moisture, and other impurities from entering and affecting the normal operation of the gas density relay. A reliable sealed chamber ensures a stable working environment for the internal components, improving the measurement accuracy and service life of the gas density relay. The transparent cover 14 also allows users to easily observe the indication of the internal pointer mechanism 7.

[0054] The first chamber 4 is filled with a medium and the filling inlet is sealed:

[0055] Before filling with gas or oil at standard atmospheric pressure, the purity of the medium is tested to ensure it meets relevant standards. Using high-precision pressure control equipment, the gas or oil is slowly filled into the first chamber 4 through the filling inlet 24. During the filling process, the pressure change within the first chamber 4 is monitored in real time to ensure that the filling pressure reaches standard atmospheric pressure. After filling, an appropriate amount of thread sealant is applied to the threaded portion of the threaded plug 25, and then tightened with a dedicated torque wrench to the specified torque value to ensure that the filling inlet 24 is completely sealed. Filling with gas or oil at standard atmospheric pressure provides an initial pressure environment for the Baden tube 6, enabling it to respond to subsequent pressure changes. The threaded plug 25, in conjunction with the thread sealant, prevents leakage of the filled medium and ensures stable pressure within the sealed chamber 4. A stable initial pressure environment ensures the accuracy and consistency of the gas density relay measurement, and effective sealing measures ensure the stability of the internal pressure environment, avoiding measurement errors caused by medium leakage.

[0056] Install external components and tighten them:

[0057] When installing the sealing ring 21 on the front end face of the transparent cover 14, first clean the front end face to ensure that the surface is flat and clean, and then accurately embed the sealing ring 21 into the preset sealing groove. When installing the glass plate 26, apply a thin layer of sealing grease to the contact surface between the glass plate 26 and the sealing ring 21 to further improve the sealing effect, and then install the glass plate 26 in place. When putting the protective cover 13 on the outside of the transparent cover 14, pay attention to adjusting the position of the protective cover 13 so that it evenly presses the glass plate 26. When installing the pressure plate 22 at the rear end of the end cap 15, first place a buffer pad on the contact surface between the pressure plate 22 and the end cap 15 (no buffer pad in the first and second embodiments), and then use bolts to fasten the pressure plate 22 to the end cap 15. Control the tightening torque with a torque wrench to ensure that the pressure plate 22 evenly presses the end cap 15. The sealing ring 21 and sealing grease are used to enhance the sealing between the glass plate 26 and the transparent cover 14 to prevent external moisture, dust, etc. from entering. The protective cover 13 serves two purposes: firstly, it protects the internal components from damage caused by external impacts; secondly, it presses down on the glass plate 26 to further ensure a tight seal. The pressure plate 22 reinforces the end cap 15 from the rear, ensuring the stability of the entire sealing structure. These excellent sealing and protective measures improve the environmental adaptability and reliability of the gas density relay, ensuring its normal operation in various complex environments.

[0058] Secondary assembly forms a second chamber:

[0059] Extended operating steps: When assembling the bellows 10, micro switch 11, and inflation connector 3 with the sealing shell 19, first install the sealing gasket in the mounting groove of the sealing shell 19, then install the bellows 10, micro switch 11, and inflation connector 3 in sequence, and tighten them using dedicated fasteners. Before inserting the connector 18 of the base 5 into the insertion tube 20 of the sealing shell 19, apply sealant to the contact surfaces of the connector 18 and the insertion tube 20, then slowly insert it to ensure a sealed connection. Finally, use bolts, nuts, and other fasteners to fix the sealing shell 19 and the protective cover 13 together. During the connection process, pay attention to adjusting their positions to ensure the coaxiality and stability of the overall structure. The bellows 10 is used to sense changes in external gas pressure and transmit these changes to the micro switch 11. The micro switch 11 then controls the circuit's on / off state based on the movement of the bellows 10, realizing the monitoring and alarm function for changes in gas density. The inflation connector 3 is used to replenish or detect external gas when needed. Through secondary assembly and connection, the gas density relay achieves functions such as pressure sensing, signal control, and overall protection, enabling it to accurately monitor changes in gas density and promptly issue alarm signals in abnormal situations.

[0060] The manufacturing method of the gas density relay of the present invention also has the beneficial effects of the gas density relay of the present invention described above, which will not be repeated here.

[0061] As shown in Figure 1, the sealing ring 21 between the end cap 15 and the transparent cover 14 is located in the sealing groove 33 on the side of the end cap 15. After the transparent cover 14 and the end cap 15 are assembled, the protective cover 13 is put on the outside of the transparent cover 14. In this way, the protective cover 13 can tightly wrap the transparent cover 14, and the transparent cover 14 is not easy to deform, so that the sealing ring 21 will loosen and leak air.

[0062] Example 2:

[0063] As shown in Figure 3, the density relay in Figure 3 is the same as the density relay in Figure 1 in terms of basic structure and principle. The main difference between the density relay in Figure 3 and the density relay in Figure 1 lies in the structural form of the base 5. In Figure 3, the connection hole 17 on the end cover 15 of the display device 1 is located at the center of the end cover 15, and the connector 18 on the base 5 is also located at the center of the end cover 15 so that it can be adapted to the connection hole 17. The air passage 8 extends outward from the center of the connector 18 to communicate with the air inlet of the Baden tube 6. In addition, the pressure plate 22 of the density relay in Figure 2 is fixed to the end cover 15 by fixing screws 27. The remaining design and basic structure of the density relay in Figure 3 are the same as those in Figure 1, and will not be described again here.

[0064] Example 3:

[0065] As shown in Figure 4, the density relay in Figure 4 has the same display device 1 as the density relay in Figure 1, and the base 5 has the same structure. However, the pressure plate 22 is not set behind the base 5. Unlike the density relay in Figure 1, the density relay in Figure 4 connects the intermediate housing 29 and the rear housing 30 at the rear end of the protective cover 13. The intermediate housing 29 and the rear housing 30 are connected. The inner cavity of the sealing shell 19 is the second chamber 9. The second chamber 9 is a sealed cavity formed between the outer side of the bellows 10 and the lower bottom plate of the bellows 10. The bellows 10, the micro switch 11, and the top rod 12 are installed in the second chamber 9. The air inlet 3 is connected to the sealing shell 19. The outer diameter of the intermediate housing 29 and the rear housing 30 is the same as the outer diameter of the protective cover 13, and they are coaxially installed together. In this way, the intermediate housing 29, the rear housing 30, and the protective cover 13 are assembled together to form a cylindrical structure with equal outer diameter. Thus, as shown in Figure 5, the overall shape and structure of the density relay are similar to those of existing density relays, eliminating the need for separate type testing before operation. A smart control component 28 is housed in the rear housing 30, as shown in Figure 6. The smart control component 28 includes a smart microprocessor, pressure and temperature sensors, a power module, and a communication module. The smart microprocessor calculates the gas density value based on the pressure and temperature values ​​collected by the pressure and temperature sensors; the communication module uploads the calculated gas density value to the target device or platform.

[0066] Based on the technical solutions of the above embodiments, the gas density relay of the present invention eliminates the need for a metal capillary tube, thereby avoiding breakage of the metal capillary tube due to vibration during assembly or use. Furthermore, since the first and second chambers of the display device 1 are not connected in the gas path and are isolated from each other, compensating gas or oil can be filled into the first chamber of the display device to overcome the influence of factors such as altitude or vibration on display accuracy. The manufacturing method of the gas density relay of the present invention also possesses the aforementioned beneficial effects of the gas density relay of the present invention, which will not be elaborated upon here.

[0067] In summary, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0068] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A gas density relay, comprising a display device, a contact device, and a gas filling connector, characterized in that: The display device has a first chamber, in which a base, a Baden tube, and a pointer mechanism are provided. One end of the Baden tube is fixed to the base, and the other end of the Baden tube is drivenly connected to the pointer mechanism. An air passage is provided in the base, and the inner cavity of the Baden tube communicates with the air passage. The contact device has a second chamber, which is connected to the inflation connector. The air passage is connected to the second chamber. The second chamber is equipped with a bellows and a micro switch. The inner cavity of the bellows is sealed with pre-filled gas. One end of the bellows is fixedly installed, and the other end of the bellows is connected to a push rod for triggering the micro switch.

2. The gas density relay according to claim 1, characterized in that: The display device includes a protective cover, a transparent cover, and an end cap. The protective cover is fitted over the outside of the transparent cover. The front end of the protective cover has an observation window, and the front end of the transparent cover faces the observation window. The opening at the rear end of the transparent cover is sealed by the end cap. The space between the transparent cover and the end cap forms the first chamber. The end cap has a connection hole, and the base has a connector. The air inlet of the air passage is located at the end of the connector. The connector is inserted into the connection hole, and the connector and the connection hole are sealed together.

3. The gas density relay according to claim 2, characterized in that: The contact device has a sealing shell, the inner cavity of which is the second chamber. The sealing shell has a forward-protruding insertion tube, and the connector is inserted into the insertion tube, with a sealed connection between the connector and the insertion tube.

4. The gas density relay according to claim 3, characterized in that: A sealing ring is provided between the connector and the connecting hole, and one or two sealing rings are provided between the connector and the insertion tube.

5. The gas density relay according to claim 3, characterized in that: The end cap is provided with a pressure plate at its rear end, which presses against the end cap, or the end cap is provided with an intermediate shell at its rear end, which presses against the end cap.

6. The gas density relay according to claim 3, characterized in that: The sealing shell and protective cover are cylindrical structures.

7. The gas density relay according to claim 3, characterized in that: The inflation connector is connected to the sealing shell, and the sealing shell is also provided with a cable connector.

8. The gas density relay according to claim 2, characterized in that: The end cap is also provided with a filling inlet, which is sealed by a threaded plug.

9. The gas density relay according to claim 2, characterized in that: The end cap and the transparent cover are sealed by a sealing ring.

10. A method for manufacturing a gas density relay, used to manufacture the gas density relay of claim 1, characterized in that, Includes the following steps: 1) Assemble the base, Baden tube, and pointer mechanism together, and then connect the connector of the base to the connection hole of the end cap; 2) Install a transparent cover on the end cap, thereby enclosing the base, Baden tube, and pointer mechanism in the first chamber between the end cap and the transparent cover; 3) Fill the first chamber with gas or oil at standard atmospheric pressure through the filling inlet, and then seal the filling inlet with a threaded plug; 4) Put a protective cover on the outside of the transparent cover, and install a pressure plate at the rear end of the end cover to press the end cover tightly, or install an intermediate shell at the rear end of the end cover to press the end cover tightly. 5) Install the bellows, micro switch and inflation connector together with the sealing shell, and then insert the connector of the base into the insertion tube of the sealing shell, and seal the connection between the connector and the insertion tube.

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