Sealed gas density monitoring device

Abstract

The utility model relates to a sealed gas density monitoring device, in the sealed gas density monitoring device, the interior of a shell is sealed into a sealed space, and gas with set gas pressure can be filled into the interior of the shell through an inflation inlet; the stable standard air pressure is kept in the shell, so that the pressure detection pipe is accurately deformed according to the air pressure in the pipe and is not influenced by the external air pressure of the shell, and the precision of the gas density monitoring device is relatively high; as the air pipe connector, the cable connector and the inflation inlet are all arranged on the bottom cover, a hole groove structure does not need to be arranged on the side wall of the shell main cylinder body to influence the structural rigidity of the shell main cylinder body, the rigidity of the shell main cylinder body is good, and the side wall of the main cylinder body is not pulled by parts such as the air pipe or the cable, so that the air pipe connector, the cable connector and the inflation inlet can be conveniently connected. The main cylinder of the shell is not prone to deformation, sealing between the observation cover and the main cylinder is not prone to being affected, and the sealing performance of the shell is good.

Description

Technical Field

[0001] The utility model relates to the field of gas density monitoring devices for electrical equipment to monitor gas density, and in particular to a sealed gas density monitoring device suitable for high altitudes. Background Art

[0002] Gas density relays and gas density gauges are widely used in the power system. The two are common gas density monitoring devices, generally divided into oil-free type and oil-filled type. The performance of these gas density monitoring devices directly affects the reliable and safe operation of their related systems. Therefore, ensuring the reliable and safe operation of these gas density monitoring devices has become one of the important tasks and jobs for people. Especially in high-altitude areas, as the altitude increases, the change in atmospheric pressure will cause a greater impact on the accuracy. Therefore, we need the gas density monitoring device to keep the whole shell in a sealed state, achieving complete isolation of the atmospheric pressure inside and outside the shell, and avoiding the occurrence of poor accuracy or oil leakage and air leakage.

[0003] At present, due to the poor sealing performance of the shells of these density relay monitoring devices, the internal pressure of the shells cannot be maintained at the set standard pressure, resulting in inaccurate measurement accuracy of the gas density monitoring devices. Through research and analysis, it is found that parts such as air pipes or electrical connectors connected to the outer side wall of the shell generate tensile loads on the local part of the shell, causing local deformation at the parts where the air pipes or electrical connectors are connected to the side wall of the shell. The shells of existing gas density monitoring devices are generally thin-walled cylindrical structures processed by stamping. Installing parts such as air pipes or electrical connectors requires opening installation holes on the outer side wall of the shell, resulting in insufficient stiffness at the parts where the air pipes or electrical connectors are connected to the shell. The shell is prone to local deformation, which in turn causes slight deformation of the sealing surface, resulting in poor sealing; the sealing effect of the shell is not good, often resulting in oil leakage or air leakage problems, and at the same time bringing errors in accuracy, causing losses to users and seriously affecting normal use in severe cases. Therefore, how to improve the sealing performance of the shell of the gas density monitoring device is a technical problem that urgently needs to be solved in this field. Summary of the Utility Model

[0004] In view of the above-mentioned disadvantages of the prior art, the technical problem to be solved by the present utility model is to provide a sealed gas density monitoring device that can improve the sealing performance of the shell of the gas density monitoring device.

[0005] To achieve the above object, the present utility model provides a sealed gas density monitoring device, including a sealed shell, a pressure detection tube and an indicating mechanism are arranged inside the shell. The pressure detection tube deforms according to the gas pressure inside the tube, thereby acting on the indicating mechanism to make the indicating mechanism indicate the gas density inside the pressure detection tube; an air pipe connector is connected to the shell; the air pipe connector communicates with the pressure detection tube and is used for inflating the pressure detection tube.

[0006] The housing includes a main cylinder, an observation cover, and a bottom cover. The observation cover seals the opening at the top end of the main cylinder. The bottom cover is hermetically connected to the bottom end of the main cylinder. The air pipe connector is provided on the bottom cover, and an inflation port for filling a set air pressure into the housing is also provided on the bottom cover. A detachable sealing plug is connected to the inflation port.

[0007] Preferably, the inflation port is a threaded hole structure. The sealing plug includes a screw head and a gland connected to the screw head. The screw head is screwed into the inflation port, and a second sealing ring is provided between the gland and the bottom cover.

[0008] Preferably, there are no holes or grooves on the side wall of the main cylinder.

[0009] Preferably, the main cylinder is machined by cutting a metal pipe.

[0010] Preferably, the sealed gas density monitoring device is a gas density relay. An alarm switch is also provided in the housing. The deformation of the pressure detection tube can drive the alarm switch to close or open. A cable connector is also connected to the housing. The cable connector is provided on the bottom cover, and the cable connector is connected to the alarm switch.

[0011] Preferably, the sealed gas density monitoring device is a gas density gauge.

[0012] Preferably, the main cylinder includes a sealing part and a barrel part. The sealing part is located at the top end of the main cylinder. The edge of the sealing part extends out a circular limiting lip towards the center of the main cylinder. A sealing groove is provided on the inner wall of the sealing part, and a first sealing ring is provided in the sealing groove. The observation cover includes a transparent sheet and a side surrounding part provided at the edge of the transparent sheet. The sealing part of the main cylinder surrounds the outside of the side surrounding part of the observation cover. The transparent sheet of the observation cover abuts against the limiting lip and exposes from the opening at the top of the main cylinder. The first sealing ring is squeezed between the side surrounding part of the observation cover and the sealing part of the main cylinder.

[0013] More preferably, the wall thickness of the sealing part is greater than the wall thickness of the barrel part.

[0014] More preferably, a positioning ring is also provided in the main cylinder, and the positioning ring abuts against the bottom end of the side surrounding part.

[0015] More preferably, the positioning ring is welded to the inner wall of the main cylinder.

[0016] As described above, a sealed gas density monitoring device of the present utility model has the following beneficial effects: In the sealed gas density monitoring device of the present utility model, the interior of the housing is sealed into a sealed space, and gas with a set air pressure can be introduced into the interior of the housing through the inflation port, so that a stable standard air pressure is maintained inside the housing, and the pressure detection tube generates accurate deformation according to the gas pressure inside the tube without being affected by the external air pressure of the housing. In this way, the accuracy of the gas density monitoring device will be relatively high; since both the gas pipe connector and the inflation port are provided on the bottom cover, there is no need to open a hole and groove structure on the side wall of the main body of the housing, which will not affect the structural stiffness of the main body of the housing. The main body of the housing has good stiffness, and the side wall of the main body will not be pulled by the gas pipe. Therefore, the main body of the housing is not prone to deformation, and the seal between the observation cover and the main body is not easily affected, and the sealing performance of the housing is good. Description of the Drawings

[0017] Figure 1 Shown is the front view of the density relay, from the perspective of observing along the axis of the housing, with the observation cover removed.

[0018] Figure 2-1 Shown is the cross-sectional view of Embodiment 1. Figure 2-2 Shown as Figure 2-1 The partial view at C in

[0019] Figure 3 Shown is the cross-sectional view of Embodiment 2.

[0020] Figure 4 Shown is the cross-sectional view of the reinforcement protective cover.

[0021] Figure 5 Shown is the cross-sectional view of Embodiment 3.

[0022] Figure 6 Shown is the cross-sectional view of Embodiment 4.

[0023] Figure 7 Shown is the cross-sectional view of Embodiment 5.

[0024] Figure 8 Shown is the cross-sectional view of Embodiment 6.

[0025] Figure 9 Shown is the cross-sectional view of Embodiment 7.

[0026] Figure 10 Shown is the front view of the gas pressure gauge, from the perspective of observing along the axis of the housing, with the observation cover removed.

[0027] Figure 11 Cross-sectional view of the gas pressure gauge.

[0028] Element Number Description

[0029]

[0030] Specific embodiments

[0031] The following specific embodiments illustrate the implementation manners of the present utility model. Those skilled in the art can easily understand other advantages and effects of the present utility model from the content disclosed in this specification.

[0032] It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in the art to understand and read, and are not used to limit the limited conditions for the implementation of the present utility model. Therefore, they do not have substantial technical significance. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present utility model can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed in the present utility model. At the same time, the terms such as "upper", "lower", "left", "right", "middle", etc. cited in this specification are only for the convenience of clear narration, rather than used to limit the scope of implementation of the present utility model. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope that the present utility model can implement.

[0033] Please refer to Figures 1 to 9 , the present utility model provides a sealed gas density monitoring device, including a sealed housing 1. Inside the housing 1, there are a pressure detection tube 13 and an indicating mechanism 14. The pressure detection tube 13 deforms according to the gas pressure inside the tube, thereby acting on the indicating mechanism 14 to make the indicating mechanism 14 indicate the gas density inside the pressure detection tube 13; an air pipe connector 16 is connected to the housing 1; the air pipe connector 16 is communicated with the pressure detection tube 13 and is used to inflate the pressure detection tube 13;

[0034] The housing 1 includes a main cylinder 2, an observation cover 9 and a bottom cover 12. The observation cover 9 seals the opening at the top of the main cylinder 2. The bottom cover 12 is hermetically connected to the bottom end of the main cylinder 2. The air pipe connector 16 is arranged on the bottom cover 12. The bottom cover 12 is also provided with an air filling port 18 for filling the housing 1 with gas at a set air pressure. A detachable sealing plug 19 is connected to the air filling port 18.

[0035] The sealed gas density monitoring device of the present utility model can be a gas density meter (a gas density meter is also often called a gas pressure gauge) or a gas density relay. Compared with the gas density relay, the gas density meter does not have parts such as an alarm switch and a cable connected to the alarm switch. Other basic structures and working principles are the same as those of the gas density relay, such as Figure 10 and Figure 11As shown, a pressure detection tube 13, an indicating mechanism 14, etc. are also provided inside the housing of the gas density gauge. The pressure detection tube 13 deforms according to the gas pressure inside the tube, thereby acting on the indicating mechanism 14 to make the indicating mechanism 14 indicate the gas density inside the pressure detection tube 13.

[0036] When the sealed gas density monitoring device of the present utility model is used in a gas density relay, please refer to Figure 2-1 , Figure 3 , Figure 5 . An alarm switch 15 is further provided inside the housing. The deformation of the pressure detection tube 13 can drive the alarm switch 15 to close or open. A cable connector 17 is also connected to the housing 1. The cable connector 17 is arranged on the bottom cover 12, and the cable connector 17 is connected to the alarm switch 15.

[0037] In the sealed gas density monitoring device of the present utility model, please refer to Figure 2-1 , Figure 3 , Figures 5 to 9 . Since the inside of the housing 1 is sealed into a sealed space, gas (such as air, nitrogen, sulfur hexafluoride gas, etc. at standard atmospheric pressure) with a set air pressure can be introduced into the inside of the housing 1 through the inflation port 18, so that the inside of the housing 1 maintains a stable set air pressure, and the pressure detection tube 13 deforms accurately according to the gas pressure inside the tube without being affected by the change of the air pressure outside the housing 1. The gas density relay is zero-calibrated according to the set air pressure, and the air pressure inside the housing 1 is maintained at the set air pressure. In this way, the accuracy of the density relay will be relatively high. The sealed gas density monitoring device of the present utility model completely isolates the inside and outside of the housing 1 through the sealing of the housing 1, thereby eliminating the influence of the change of atmospheric pressure caused by different altitudes on the accuracy. Its structure is simpler and more reliable. Moreover, since the air pipe connector 16, the cable connector 17, and the inflation port 18 are all arranged on the bottom cover 12, in this way, there is no need to open hole and groove structures on the side wall of the main cylinder 2 of the housing 1, which affects the structural stiffness of the main cylinder 2 of the housing 1. The main cylinder 2 of the housing 1 has good stiffness. Moreover, the side wall of the main cylinder 2 will not be pulled by parts such as air pipes or cables. Therefore, the main cylinder 2 of the housing 1 is not easily deformed, and the seal between the observation cover 9 and the main cylinder 2 is not easily affected. The sealing performance of the housing 1 is good, the gas inside the housing 1 will not leak, and the outside gas will not leak into the inside of the housing 1. The inside of the housing 1 maintains a stable set air pressure. Therefore, the pressure detection tube 13 deforms accurately according to the gas pressure inside the tube without being affected by the change of the air pressure outside the housing 1, and the detection accuracy of the sealed gas density monitoring device of the present utility model will be relatively high.

[0038] Gas density relays are commonly used in gas insulated switchgear (GIS). Their main function is to monitor gas density (generally the density of insulating gas such as sulfur hexafluoride (SF6) gas, and sulfur hexafluoride (SF6) gas is taken as an example below) to ensure that the equipment operates under safe and reliable conditions. The gas density relay for monitoring the density of sulfur hexafluoride (SF6) mainly includes a housing 1, a pressure detection tube 13, an indicating mechanism 14 and an alarm switch 15 arranged in the housing 1, wherein:

[0039] The pressure detection tube 13 can generally be called a pressure detection element, a bellows, a spring metal curved tube or a Baden tube, etc. One end of the pressure detection tube 13 is connected to the trachea connector 16, the trachea connector 16 is connected to the trachea 23, the trachea 23 is connected to the sulfur hexafluoride gas chamber in the equipment, and the other end of the pressure detection tube 13 is sealed. In this way, the sulfur hexafluoride gas density in the pressure detection tube 13 is the same as the gas density in the sulfur hexafluoride gas chamber of the equipment. The pressure detection tube 13 is very sensitive to changes in the gas pressure in its inner cavity and can expand and contract according to changes in the gas pressure in its inner cavity. The other end of the pressure detection tube 13 (i.e., the end of the pressure detection tube 13 that is blocked, in the following description, the other end of the pressure detection tube 13 is the end of the pressure detection tube 13 that is blocked) is connected to the indicating mechanism 14 and the alarm switch 15 in a transmission manner. Under the action of the pressure in its inner cavity, the pressure detection tube 13 is deformed according to the gas pressure in the tube, so that the other end of the pressure detection tube 13 acts on the indicating mechanism 14, so that the indicating mechanism 14 indicates the gas density in the pressure detection tube 13. The deformation of the other end of the pressure detection tube 13 can also drive the alarm switch 15 to close or open. In order to compensate for the error caused by the ambient temperature on the deformation of the pressure detection tube 13, a temperature compensation device can also be connected to the other end of the pressure detection tube 13. The temperature compensation device generally adopts a bimetallic strip 25. The temperature compensation device can compensate for the effect of temperature changes on gas pressure. The bimetallic strip 25 is made of two metals with different expansion coefficients. They expand and contract to different degrees when the temperature changes, thereby compensating for the effect of temperature on the pressure reading.

[0040] The indicating mechanism 14 generally includes a gear mechanism and a pointer 26. The gear mechanism and the pointer 26 are generally connected to the movement 28. The movement 28 and the pressure detection tube 13 are both installed on the air pipe connector 16 (the air pipe connector 16 is fixed to the housing 1 as the installation base for related parts). The deformation and telescopic movement generated at the other end of the pressure detection tube 13 is converted into the rotational movement of the pointer 26 through the gear mechanism. Generally, the pressure detection tube 13 is connected to a temperature compensation device, and the temperature compensation device is connected to the gear mechanism. After the temperature compensation device corrects the temperature of the telescopic deformation amount of the pressure detection tube 13, the movement is transmitted to the gear mechanism. The gear mechanism converts the telescopic movement of the detection tube 13 into the rotational movement of the pointer 26, and the pointer 26 indicates the scale value on the dial 27 of the gas density relay, indicating the current SF6 gas density.

[0041] The alarm switch 15 generally has alarm and locking functions. The alarm switch 15 is generally also called a micro switch, a magnetic-assisted electrical contact, etc. When the gas density in the pressure detection tube 13 is lower than the preset safety threshold, the deformation of the pressure detection tube 13 can drive the alarm switch 15 to act, thus triggering an alarm signal. If the gas density continues to drop to the locking value, the deformation of the pressure detection tube 13 can drive the alarm switch 15 to act and further trigger the locking mechanism to prevent the equipment from operating under unsafe conditions.

[0042] The basic structure and working principle of the gas density relay are prior arts. Although the names of related basic structures and parts are different in different prior literatures, the structures, functions, and principles are basically the same and are all included in the density relay related to the technical solution of the present invention. No further detailed description is given here.

[0043] In the sealed gas density monitoring device of the present utility model, the air pipe connector 16 and the cable connector 17 are generally welded to the bottom cover 12 by welding. Two holes are opened on the bottom cover 12, and the air pipe connector 16 and the cable connector 17 are respectively inserted into the two holes, and then the gaps between the air pipe connector 16 and the holes and the gaps between the cable connector 17 and the holes are welded and sealed. In order to make the local stiffness of the bottom cover 12 relatively uniform, the opening positions on the bottom cover 12 for welding the air pipe connector 16 and the cable connector 17 and the position of the inflation port 18 can be set to be approximately evenly distributed around the center of the bottom cover 12. In this way, the local stiffness of the bottom cover 12 is relatively uniform, and it is not easy to generate deformation in the area with weak local stiffness, which will not cause the main cylinder 2 to deform and affect the sealing performance. In order to facilitate the manufacture of the sealed gas density monitoring device of the present utility model, the pressure detection pipe 13 can be first welded to the air pipe connector 16, then the air pipe connector 16 and the cable connector 17 are inserted into the holes opened on the bottom cover 12 and welded. After the parts such as the indicating mechanism 14 and the alarm switch 15 are integrally assembled and debugged with the air pipe connector 16, finally, the bottom cover 12 is welded to the bottom end of the main cylinder 2.

[0044] The sealed gas density monitoring device of the present utility model is very suitable for application environments where the ambient air pressure is quite different from the standard atmospheric pressure, such as high altitude areas. The sealed gas density monitoring device of the present utility model greatly improves the reliability of the sealing performance of the gas density relay housing 1 in terms of structure, can effectively avoid the influence of atmospheric pressure changes on the accuracy, and at the same time, in the oil-filled density relay, the situation of oil leakage or air leakage can be completely avoided.

[0045] The technical solution of the present utility model will be further described below in combination with the specific implementation manners of each embodiment.

[0046] Embodiment 1:

[0047] As Figure 2-1 and Figure 2-2As shown, a pressure detection tube 13, an indicating mechanism 14 and an alarm switch 15 are arranged in the housing 1 of the gas density relay. The housing 1 includes a main cylinder 2, an observation cover 9 and a bottom cover 12. The observation cover 9 seals the opening at the top of the main cylinder 2. The bottom cover 12 is sealed and connected to the bottom end of the main cylinder 2. Generally, the bottom cover 12 can be welded to the bottom end of the main cylinder 2 by welding. The air pipe connector 16 and the cable connector 17 are both arranged on the bottom cover 12. Generally, the air pipe connector 16 and the cable connector 17 can be welded to the bottom cover 12 by welding. The welding method is relatively firm, has high structural strength and good sealing performance; of course, the air pipe connector 16 and the cable connector 17 can also be connected to the bottom cover 12 in a detachable manner. The air pipe is connected to the air pipe connector 16, and the air pipe connector 16 has an airway 24, which is connected to the pressure detection tube 13. The cable connector 17 is connected to an external cable, and the cable connector 17 is also connected to the alarm switch 15 inside the housing 1 through a signal connection line (not shown in the figure).

[0048] like Figure 2-1 and Figure 2-2 As shown, the main cylinder 2 includes a sealing portion 3 and a cylinder body 5, the sealing portion 3 is located at the top of the main cylinder 2, and an annular limiting lip 6 is extended from the edge of the sealing portion 3 toward the center of the main cylinder 2. A sealing groove 4 is provided on the inner wall of the sealing portion 3, and a first sealing ring 8 is provided in the sealing groove 4; the observation cover 9 includes a transparent sheet 10 and a side surrounding portion 11 provided on the edge of the transparent sheet 10, the sealing portion 3 of the main cylinder 2 is surrounded by the outer side of the side surrounding portion 11 of the observation cover 9, and the first sealing ring 8 is squeezed between the side surrounding portion 11 of the observation cover 9 and the sealing portion 3 of the main cylinder 2 so that the outer wall of the observation cover 9 and the inner wall of the sealing portion 3 are sealed; the transparent sheet 10 of the observation cover 9 is against the limiting lip 6 and exposed from the opening at the top of the main cylinder 2, so that the observation cover 9 cannot be detached from the opening at the top of the main cylinder 2 and the scale value indicated by the pointer 26 can be observed from the opening at the top of the main cylinder 2. Moreover, since the limiting lip 6 and the sealing portion 3 form a corner structure similar to a wall corner, the limiting lip 6 strengthens the structural rigidity of the sealing portion 3, and the sealing portion 3 is not easily deformed to cause the seal to loosen, shift, and leak.

[0049] like Figure 2-1 and Figure 2-2As shown, a positioning ring 7 is also provided in the main cylinder body 2. The positioning ring 7 abuts against the bottom end of the side surrounding portion 11 of the observation cover 9. In this way, the transparent sheet 10 at the top end of the observation cover 9 abuts against the limiting lip 6, and the bottom end of the side surrounding portion 11 of the observation cover 9 abuts against the positioning ring 7. The observation cover 9 is positioned on the axis and cannot move axially, so the seal between the first sealing ring 8, the observation cover 9 and the sealing portion 3 will not become loose and displaced to cause leakage. The positioning ring 7 can be welded to the inner wall of the main cylinder body 2 by welding. In order to achieve a better sealing effect, two sealing grooves 4 are provided on the inner wall of the sealing portion 3, and a first sealing ring 8 is provided in each sealing groove 4.

[0050] As Figure 2-1 and Figure 2-2 shown, in order to achieve an even better sealing effect, the sealing portion 3 is thickened. The wall thickness of the sealing portion 3 is greater than the wall thickness of the barrel portion 5. In this way, the structural stiffness of the sealing portion 3 is relatively high, and it is not easy to deform, resulting in the loosening and displacement of the first sealing ring 8 and causing leakage.

[0051] As Figure 2-1 and Figure 2-2 shown, an air inlet 18 for filling the housing 1 with a gas at a set air pressure is further provided on the bottom cover 12, and a detachable sealing plug 19 is connected to the air inlet 18. After filling the housing 1 with a set pressure through the air inlet 18, the air inlet 18 is sealed with the sealing plug 19. The sealing plug 19 includes a screw head 20 and a gland 21 connected to the screw head 20. The air inlet 18 is a threaded hole structure. The screw head 20 of the sealing plug 19 is screwed into the air inlet 18, and a second sealing ring 22 is provided between the gland 21 and the bottom cover 12. Of course, the sealing plug 19 can adopt a self-sealing valve structure form and automatically seal after filling the gas.

[0052] As Figure 2-1 and Figure 2-2 shown, there are no holes, grooves or other structures on the side wall of the main cylinder body 2. In this way, the side wall of the main cylinder body 2 is smooth and complete, without stress concentration points, and the main cylinder body 2 is not easy to deform, resulting in the loosening and displacement of the sealing position and causing leakage. The main cylinder body 2 can be machined by cutting a metal pipe, such as a steel pipe or an aluminum pipe. In this manufacturing method, the structural stiffness and strength of the main cylinder body 2 formed by relative stamping or rolling are higher, and the main cylinder body 2 is not easy to deform, resulting in the loosening and displacement of the sealing position and causing leakage.

[0053] Figure 2-1 and Figure 2-2 The manufacturing method of the gas density relay shown is as follows:

[0054] 1) Weld the pressure detection pipe 13 to the gas pipe connector 16, and then weld the gas pipe connector 16 and the cable connector 17 to the bottom cover 1, and weld the gas pipe 23 to the gas pipe connector 16 together to form a bottom cover assembly, including:

[0055] 1.1) Weld the pressure detection tube 13 to the air pipe connector 16.

[0056] The air passage in the air pipe connector 16 communicates with the inner cavity of the pressure detection tube 13. The air pipe connector 16 serves as a base for installing other related components in subsequent manufacturing and assembly.

[0057] 1.2) Weld the cable connector 17 to the bottom cover 12 and weld the air pipe connector 16 to the bottom cover 12.

[0058] Seal the welds between the bottom cover 12, the cable connector 17, and the air pipe connector 16.

[0059] 1.3) Weld the air pipe 23 to the air pipe connector 16 and seal the weld.

[0060] 2) Install the movement 28, bimetallic strip 25, pointer 26, alarm switch 15, and dial 27 on the bottom cover assembly to form a bare gas density relay, including:

[0061] 2.1) Connect the movement 28 to the air pipe connector 16 through fasteners.

[0062] 2.2) Connect the bimetallic strip 25 between the movement 28 and the pressure detection tube 13. Fasteners can be used to connect the bimetallic strip 25 between the movement 28 and the pressure detection tube 13.

[0063] 2.3) Connect the pointer 26 to the movement 28 through fasteners.

[0064] 2.4) Connect the alarm switch 15 to the air pipe connector 16 through fasteners.

[0065] 2.5) Connect the dial 27 to the alarm switch 15 through fasteners.

[0066] 2.6) Connect the cable connector 17 to the alarm switch 15 through a signal connecting wire (not marked in the figure).

[0067] 3) Debug the bare gas density relay, including:

[0068] 3.1) Conduct pressure accuracy debugging on the gas pressure in the pressure detection tube 13 and the indicated value corresponding to the pointer 26 according to requirements.

[0069] 3.2) Debug the action threshold of the alarm switch 15.

[0070] 4) Install the first sealing ring 8 in the sealing groove 4 of the main cylinder body 2, insert the observation cover 9 into the main cylinder body 2 and fix it to form a cylinder body assembly, including:

[0071] 4.1) Install the first sealing ring 8 in the sealing groove 4 of the main cylinder body 2.

[0072] 4.2) Insert the observation cover 9 forward from the bottom end of the main cylinder body 2 so that the side surrounding part 11 of the observation cover 2 cooperates with the sealing part 3, and the top of the observation cover 9 presses tightly against the main cylinder body 2;

[0073] 4.3) Place the positioning ring 7 into the main cylinder body 2 so that the positioning ring 7 abuts against the bottom end of the observation cover 9, and weld the positioning ring 7 to the main cylinder body 2. Spot welding can be adopted for welding;

[0074] 5) Cover the cylinder body assembly on the bare machine of the gas density relay, and seal all parts such as the pressure detection pipe 13, the movement 28, and the dial 27 in the cylinder body assembly, including:

[0075] 5.1) Cover the main cylinder body 2 on the bottom cover 12 so that the main cylinder body 2 accommodates all the pressure detection pipe 13, the movement 28, the bimetallic strip 25, the pointer 26, the alarm switch 15, and the dial 27 on the bottom cover 12 within the main cylinder body 2;

[0076] In short, the main cylinder body 2 accommodates all the relevant parts on the side of the bottom cover 12 where the pressure detection pipe 13 is installed, and aligns the bottom end edge of the main cylinder body 2 with the edge of the bottom cover 12 coaxially, preparing to weld the bottom end edge of the main cylinder body 2 and the edge of the bottom cover 12;

[0077] 5.2) Weld the full weld seam of the bottom end edge of the main cylinder body 2 and the edge of the bottom cover 12 to make the weld seam sealed;

[0078] 6) Fill the inner cavity of the housing with gas at a set air pressure and seal the housing, including:

[0079] 6.1) After completing the assembly, fill the inner cavity of the housing with gas at a set air pressure from the gas filling port 18;

[0080] 6.2) Plug the gas filling port 18 with the sealing plug 19 to keep the inner cavity of the housing at the set air pressure.

[0081] Embodiment 2:

[0082] As Figure 3 shown, different from the structure of the gas density relay in Figure 2-1 is that Figure 3The side enclosure 11 of the observation cover 9 of the gas density relay therein is relatively long, and the side enclosure 11 surrounds the outside of the sealing part 3 of the main cylinder body 2. The outer diameter of the sealing part 3 on the main cylinder body 2 is smaller than that of other parts of the main cylinder body 2. A sealing groove 4 is provided on the outer side of the sealing part 3. The first sealing ring 8 is arranged in the sealing groove 4, and the first sealing ring 8 seals between the side enclosure 11 of the observation cover 9 and the sealing part 3 of the main cylinder body 2. The main cylinder body 2 is processed by cutting a metal pipe into an integral structure. The observation cover 9 is made of a transparent material, not limited to transparent glass or transparent resin. Since the observation cover 9 is made of a non-metallic material, its strength is relatively low. In order to enhance the strength and stiffness of the observation cover 9, a reinforcing protective cover 29 is sleeved outside the observation cover 9. An observation port 30 is provided at the top of the reinforcing protective cover 29 (please refer to Figure 3 and Figure 4 ). The top of the observation cover 9 is exposed from the observation port 30. The reinforcing protective cover 29 presses the observation cover 9 against the top of the main cylinder body 2. The reinforcing protective cover 29 is fixed on the main cylinder body 2. The edge at the bottom of the reinforcing protective cover 29 can be welded to the main cylinder body 2 by welding; the outer diameter of the reinforcing protective cover 29 is the same as that of the main cylinder body 2, and the connection seam between the reinforcing protective cover 29 and the outer side wall of the main cylinder body 2 is flush. Figure 3 The other structures of the density relay in Figure 2-1 are the same, and will not be elaborated here.

[0083] Embodiment 3:

[0084] As shown in Figure 5 and different from the gas density relay structure in Figure 3 , the main cylinder body 2 of the gas density relay in Figure 5 is manufactured and processed in a split manner. The sealing part 3 of the main cylinder body 2 is processed from a section of metal pipe, and the barrel part 5 of the main cylinder body 2 is processed from another section of metal pipe. Then, the two processed metal pipes are welded together to form the main cylinder body 2. Figure 5 The remaining structures of the density relay in Figure 3 are the same as those of the density relay in

[0085] and will not be elaborated here.

[0086] Embodiment 4: Figure 6 As shown in Figure 2-1 and different from the gas density relay structure in Figure 6 , the main cylinder body 2 of the gas density relay in Figure 6The observation cover 9 in it is sleeved on the outside of the sealing part (a section at the top of the main cylinder body 2 is the sealing part, not marked in the figure). The outer side wall of the sealing part is the sealing surface. The sealing part is not provided with a sealing groove, and the sealing groove is arranged on the inner side wall of the side surrounding part 11 of the observation cover 9. A first sealing ring 8 is arranged in the sealing groove. In order to enhance the strength and rigidity of the observation cover 9, a reinforcing protective cover 29 is sleeved on the outside of the observation cover 9. An observation port 30 is arranged at the top end of the reinforcing protective cover 29, and the top of the observation cover 9 is exposed from the observation port 30. The reinforcing protective cover 29 presses the observation cover 9 against the top end of the main cylinder body 2. The reinforcing protective cover 29 is fixed on the main cylinder body 2, and the edge at the bottom of the reinforcing protective cover 29 can be welded to the main cylinder body 2 by welding. Figure 6 The other structures of the density relay in Figure 2-1 are the same, and will not be elaborated here.

[0087] Embodiment Five:

[0088] As Figure 7 shown, different from the gas density relay structure in Figure 6 , in Figure 7 , the side surrounding part 11 of the observation cover 9 of the gas density relay is lined on the inside of the sealing part of the main cylinder body 2. The inner side wall of the sealing part (a section at the top of the main cylinder body 2 is the sealing part, not marked in the figure) is the sealing surface. The sealing part is also not provided with a sealing groove, and the sealing groove is arranged on the outer side wall of the side surrounding part 11 of the observation cover 9. A first sealing ring 8 is arranged in the sealing groove; a step surface (not marked in the figure) is arranged at the transition between the top end and the side surrounding part 11 of the observation cover 9, and the top end of the main cylinder body 2 abuts against the step surface. Similarly, in order to enhance the strength and rigidity of the observation cover 9, a reinforcing protective cover 29 is sleeved on the outside of the observation cover 9. An observation port 30 is arranged at the top end of the reinforcing protective cover 29, and the top of the observation cover 9 is exposed from the observation port 30. The reinforcing protective cover 29 presses the observation cover 9 against the top end of the main cylinder body 2. The reinforcing protective cover 29 is fixed on the main cylinder body 2, and the edge at the bottom of the reinforcing protective cover 29 can be welded to the main cylinder body 2 by welding;, or internal threads can be arranged on the inner side wall at the bottom end of the reinforcing protective cover 29, and external threads can be arranged at the top end of the main cylinder body 2, and the reinforcing protective cover 29 is threadedly connected to the main cylinder body 2. Figure 7 The other structures of the density relay in Figure 6 are the same, and will not be elaborated here.

[0089] Embodiment Six:

[0090] As Figure 8 shown, different from the gas density relay structures in Figure 6 and Figure 7 , in Figure 8The sealing part 3 of the gas density relay therein is a circular ring structure with an annular end face provided at the top end of the main cylinder body 2. A sealing groove can be provided on the end face of the sealing part 3, and the first sealing ring 8 is arranged in the sealing groove. The observation cover 9 is a circular transparent sheet 10, and the observation cover 9 presses on the end face of the sealing part 3 to press the first sealing ring 8 tightly. Similarly, in order to enhance the strength and rigidity of the observation cover 9, a reinforcing protective cover 29 is sleeved outside the observation cover 9. An observation port 30 is provided at the top end of the reinforcing protective cover 29, and the observation cover 9 exposes from the observation port 30. The reinforcing protective cover 29 presses the observation cover 9 against the top end of the main cylinder body 2. The reinforcing protective cover 29 is fixed on the main cylinder body 2. The edge at the bottom of the reinforcing protective cover 29 can be welded to the main cylinder body 2 by welding, or internal threads can be provided on the inner side wall at the bottom end of the reinforcing protective cover 29, and external threads can be provided at the top end of the main cylinder body 2 to thread-connect the reinforcing protective cover 29 and the main cylinder body 2 together. Figure 8 The other structures of the density relay therein are the same as Figure 6 and Figure 7 which will not be elaborated herein. Figure 8 The gas density relay shown has a relatively large axial stiffness of the housing 1 due to the adoption of the end face sealing form, and the sealing position is not prone to deformation, and the sealing performance is good.

[0091] Embodiment Seven:

[0092] As Figure 9 shown, Figure 9 the sealing part 3 of the gas density relay therein is also a circular ring structure with an annular end face provided at the top end of the main cylinder body 2, and the observation cover 9 is a circular transparent sheet 10. Different from the gas density relay structure in Figure 8 the gas density relay in Figure 9 the observation cover 9 of the gas density relay is arranged inside the sealing part 3. A sealing groove can be provided on the observation cover 9, and the first sealing ring 8 is arranged in the sealing groove. The first sealing ring 8 is located between the sealing part 3 and the observation cover 9 and is clamped by both of them, thereby sealing the inner cavity of the housing 1. In order to fix the observation cover 9, a positioning ring 7 is also lined in the inner cavity of the main cylinder body 2. The observation cover 9 is clamped between the sealing part 3 and the positioning ring 7, and the positioning ring 7 is welded to the inner wall of the main cylinder body 2. Different from the gas density relay structure in Figures 6 to 8 the gas density relay in Figure 9 the gas density relay does not require the reinforcing protective cover 29. Figure 9 The gas density relay shown has a relatively large axial stiffness of the housing 1 due to the adoption of the end face sealing form, and the sealing position is not prone to deformation, and the sealing performance is good.

[0093] Embodiment Eight:

[0094] As described above, the difference between the gas density gauge and the gas density relay lies only in that the gas density gauge does not require an alarm switch, as well as the signal connecting wires, cable connectors and other parts corresponding to the alarm switch. The other basic structures and basic principles are the same as those of the gas density relay. As Figure 10 and Figure 11 shown, a pressure detection tube 13 and an indicating mechanism 14 are provided in the housing 1 of the gas density gauge. Different from the gas density relay in Figure 2-1 and Figure 2-2 , Figure 10 and Figure 11 , there is no alarm switch in the housing 1 of the gas density gauge, so there is no need to set a cable connector on the bottom cover 12. As Figure 10 and Figure 11 shown, the housing 1 of the gas density gauge includes a main cylinder body 2, an observation cover 9 and a bottom cover 12. The observation cover 9 seals the opening at the top of the main cylinder body 2, and the bottom cover 12 is sealingly connected to the bottom end of the main cylinder body 2. The air pipe connector 16 is provided on the bottom cover 12. Generally, the air pipe connector 16 can be welded to the bottom cover 12 by welding. The welding method is relatively firm, with high structural strength and good sealing performance.

[0095] A manufacturing method of a sealed gas density monitoring device involved in the present application includes the following steps:

[0096] 1) Weld the pressure detection tube and the air pipe connector, and then weld or sealingly fix the air pipe connector on the bottom cover (for example, the air pipe joint can be connected to the bottom cover by means of threaded connection plus a seal, or the air pipe joint can be connected to the bottom cover by means of thread plus a filler seal), and weld or sealingly fix the air pipe and the air pipe connector together (for example, the air pipe joint can be connected to the air pipe by means of threaded connection plus a seal, or the air pipe joint can be connected to the air pipe by means of thread plus a filler seal) to form a bottom cover assembly;

[0097] 2) Install the movement, bimetallic strip, pointer and dial on the bottom cover assembly to form a bare machine of the gas density monitoring device;

[0098] 3) Debug the bare machine of the gas density monitoring device;

[0099] 4) Install the first sealing ring in the sealing groove of the main cylinder body, and install and fix the observation cover into the main cylinder body to form a cylinder body assembly;

[0100] 5) Cover the cylinder body assembly on the bare machine of the gas density monitoring device, and seal the pressure detection tube, movement, bimetallic strip, pointer and dial all in the cylinder body assembly;

[0101] 6) Fill the inner cavity of the housing with gas at a set air pressure and seal the housing.

[0102] Based on the technical solutions of the above embodiments, the housing of the sealed gas density monitoring device of the present utility model is not prone to deformation, the seal between the observation cover and the main cylinder is not easily affected, the sealing performance of the housing is good, and a stable set air pressure is maintained inside the housing. Therefore, the pressure detection tube generates accurate deformation according to the gas pressure inside the tube without being affected by the change of the external air pressure of the housing, and the detection accuracy is relatively high.

[0103] In summary, the present utility model effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

[0104] The above embodiments are only illustrative of the principles and effects of the present utility model, and are not used to limit the present utility model. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present utility model. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present utility model should still be covered by the claims of the present utility model.

Claims

1. A sealed gas density monitoring device, comprising a sealed housing, a pressure detection tube and an indicating mechanism arranged in the housing, the pressure detection tube deforms according to the gas pressure in the tube, thereby acting on the indicating mechanism so that the indicating mechanism indicates the gas density in the pressure detection tube; an air pipe connector is connected to the housing; the air pipe connector is connected to the pressure detection tube and is used to inflate the pressure detection tube; the characteristics are: The shell includes a main cylinder, an observation cover and a bottom cover. The observation cover seals the opening at the top end of the main cylinder. The bottom cover is sealingly connected to the bottom end of the main cylinder. The air pipe connector is arranged on the bottom cover. The bottom cover is also provided with an inflation port for filling gas with a set air pressure into the shell. A detachable sealing plug is connected to the inflation port.

2. The sealed gas density monitoring device according to claim 1, characterized in that: The inflation port is a threaded hole structure, and the sealing plug includes a screw head and a pressure cover connected to the screw head. The screw head is screwed into the inflation port, and a second sealing ring is provided between the pressure cover and the bottom cover.

3. The sealed gas density monitoring device according to claim 1, characterized in that: There are no holes or grooves on the side wall of the main cylinder.

4. The sealed gas density monitoring device according to claim 1, characterized in that: The main cylinder is formed by cutting a metal pipe.

5. The sealed gas density monitoring device according to claim 1, characterized in that: The sealed gas density monitoring device is a gas density relay, and an alarm switch is also provided in the shell. The deformation of the pressure detection tube can drive the alarm switch to close or open; a cable connector is also connected to the shell, and the cable connector is arranged on the bottom cover, and the cable connector is connected to the alarm switch.

6. The sealed gas density monitoring device according to claim 1, characterized in that: The sealed gas density monitoring device is a gas density meter.

7. The sealed gas density monitoring device according to claim 1, characterized in that: The main cylinder body includes a sealing portion and a cylinder body portion, the sealing portion is located at the top end of the main cylinder body, the edge of the sealing portion extends an annular limiting lip toward the center of the main cylinder body, the inner wall of the sealing portion is provided with a sealing groove, and the sealing groove is provided with a first sealing ring; the observation cover includes a transparent sheet and a side surrounding portion provided at the edge of the transparent sheet, the sealing portion of the main cylinder body is surrounded by the outer side of the side surrounding portion of the observation cover, the transparent sheet of the observation cover is abutted against the limiting lip and exposed from the opening at the top of the main cylinder body, and the first sealing ring is squeezed between the side surrounding portion of the observation cover and the sealing portion of the main cylinder body.

8. The sealed gas density monitoring device according to claim 7, characterized in that: The wall thickness of the sealing portion is greater than the wall thickness of the barrel portion.

9. The sealed gas density monitoring device according to claim 6, characterized in that: A positioning ring is also provided in the main cylinder, and the positioning ring abuts against the bottom end of the side surrounding part.

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