CN212113337U

CN212113337U - Lightning arrester with built-in anti-falling mechanism and lightning protection fusing combination device

Info

Publication number: CN212113337U
Application number: CN202021032318.5U
Authority: CN
Inventors: 岳夕皓; 郑春雨
Original assignee: Shaanxi Heshuo Electrical Co ltd
Current assignee: Shaanxi Heshuo Electrical Co ltd
Priority date: 2020-06-08
Filing date: 2020-06-08
Publication date: 2020-12-08
Anticipated expiration: 2030-06-08

Abstract

The utility model discloses a lightning arrester with a built-in anti-falling mechanism and a lightning protection fusing combination device, wherein the lightning arrester comprises an insulator main body, a bell mouth main body and a lightning arrester body, and the bell mouth main body is connected with the lower opening of an insulating pipe at the lower end of a sub-insulator main body; the outer ring of the top of the lightning arrester body is provided with a brim; the inside claw type packing ring that is provided with of horn mouth main part, the claw type packing ring includes the many elastic claws that collar and collar lower part set up, the top and the collar of every elastic claw are solid and unite as an organic whole, the elastic claw incurved forms the arch at the middle part, when the arrester body became invalid and drops, the claw type packing ring that is in the lower part of insulator cavity has blockked the brim of a hat at arrester body top, the falling of arrester body has been prevented, because make full use of the length of arrester body, make the arrester body after taking off apart from the earthing terminal distance farthest, can effectively break away from with the main line after having ensured the arrester body to become invalid, make the safe distance maximize.

Description

Lightning arrester with built-in anti-falling mechanism and lightning protection fusing combination device

Technical Field

The utility model belongs to the technical field of power transmission and distribution, a built-in arrester and lightning-arrest fusing composite set who prevents weighing down mechanism is related to.

Background

An RW series drop-out fuse and an MOA series zinc oxide arrester are generally required to be installed at the offline position of a 10kV distribution network terminal to provide overcurrent and lightning protection for a distribution transformer, and a typical installation method of double-pole double-cross-arm up-in and down-out is generally adopted in the installation mode. The installation mode increases the complexity and the complexity of the installation process of the drop-out fuse and the zinc oxide arrester, and the drop-out fuse and the zinc oxide arrester cannot be safely separated from the system to operate in time when the zinc oxide arrester fails or fails, so that the operation and maintenance workload of the distribution network terminal 10kV side is increased.

The patent of this company with application number 201911351440.0 "an indoor automatic tripping arrester" discloses an automatic tripping arrester, and this arrester is furnished with anti-falling device, and this anti-falling device installs and imports and exports the position in insulator lower extreme arrester installation storehouse, and the arrester is caught on the anti-falling boss of arrester lower extreme by anti-falling movable hook when the inefficacy drops, has avoided directly falling to ground emergence accident. The problem that exists in the application is that the safe distance between the arrester and the earthing terminal arranged in the middle of the umbrella skirt is not enough after the arrester falls off after failure. Especially in severe environment and heavy pollution areas, special requirements are made on the safety distance between the arrester after failure and falling and the grounding end, so that the length of the hook body of the anti-falling hook can only be increased to ensure that the arrester can be effectively separated from a main line after failure. Therefore, the anti-falling device can be lengthened, the cost of parts, the packaging cost and the transportation cost are increased, and the overall attractiveness of the product is influenced by the overlong anti-falling device.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a built-in arrester and lightning-arrest fusing composite set who prevents weighing down mechanism adopts built-in anti-falling structure, solves the arrester and prevents weighing down the problem that mechanism restriction safe distance to retrench whole composite set structure, promoted the pleasing to the eye degree of product.

The utility model discloses a utility model main points are: the outer structure of the upper end separation device of the lightning arrester body is changed, the brim is additionally arranged on the edge of the upper end sealing cover of the separation device, the brim is used for providing a hanging point for the whole lightning arrester body during falling, then a claw-shaped gasket is arranged between a bell mouth at the lower end of the combination device and the glass fiber tube, the convex part of the side surface of the gasket is matched with the brim at the upper end of the separation device for use, the lightning arrester body is hung on the hood, the anti-falling effect is generated, and the safety distance is increased.

The technical scheme of the utility model as follows:

a lightning arrester with a built-in anti-falling mechanism comprises an insulator main body, a bell mouth main body and a lightning arrester body, wherein the lightning arrester body is arranged in the insulator main body of a sealing cylinder structure, and the bell mouth main body is connected to a lower opening of an insulating pipe at the lower end of a sub-insulator main body; the outer ring of the top of the lightning arrester body is provided with a brim; the inside claw type packing ring that is provided with of horn mouth main part, claw type packing ring includes the many elastic claw that collar and collar lower part set up, the top of every elastic claw is integrated with the collar is fixed, the inward bending of elastic claw forms the arch in the middle part, the arch realize blockking to the brim of a hat when the arrester body drops.

In the lightning arrester with the built-in anti-falling mechanism, one side of the ring body of the mounting ring is provided with the mounting notch, and the mounting notch penetrates through the whole ring body.

In the lightning arrester with the built-in anti-falling mechanism, a gasket mounting groove and a gasket movable groove are arranged in the horn mouth main body from top to bottom; the mounting ring of the claw-shaped gasket is mounted in the gasket mounting groove, and the gasket movable groove corresponds to the position of the elastic claw bulge.

In the arrester with the built-in anti-falling mechanism, the outer ring of the middle lower part of the arrester body is provided with the conductive convex ring, the limiting groove is arranged in the horn mouth main body, and the conductive contact surface on the upper part of the limiting groove is contacted with the conductive convex ring when the arrester body works normally.

In the lightning arrester with the built-in anti-falling mechanism, the outer ring of the insulator main body is provided with the fixing piece.

In the lightning arrester with the built-in anti-falling mechanism, the magnet adsorption block is arranged inside the insulator main body and fixed on the fixing piece.

In the lightning arrester with the built-in anti-falling mechanism, the magnet is arranged in the separation unit at the upper end of the lightning arrester body and is adsorbed with the magnet adsorption block.

In the lightning arrester with the built-in anti-falling mechanism, the insulator main body comprises an insulating pipe with the upper end sealed, the umbrella skirt main body is sleeved on the outer ring of the insulating pipe, and the lower opening of the insulating pipe is arranged at the lower end of the umbrella skirt main body.

A lightning protection and fusing combination device with a built-in anti-falling mechanism comprises a fuse protector and a lightning arrester, wherein an upper end fixing piece is connected with the upper parts of an insulator main body and the fuse protector, and the upper end fixing piece is connected with a high-voltage wire inlet end of an external power transmission line.

In the lightning protection and fusing combined device with the built-in anti-falling mechanism, the lower end fixing piece is connected to the lower portions of the insulator main body and the fuse, and is fixed between the lower opening of the insulating tube and the bell mouth main body.

The utility model has the advantages as follows:

1. the utility model discloses place insulator cavity inside with the anti-falling mechanism of arrester body in, and the lower part at the insulator cavity has set up the claw type packing ring, when the arrester body became invalid and drops, the claw type packing ring that is in the lower part of insulator cavity has blockked the brim of a hat at arrester body top, the falling of arrester body has been prevented, because make full use of the length of arrester body, make the arrester body after the dropout keep away from the earthing terminal distance farthest, ensured that the arrester body can effectively break away from with the main line after becoming invalid, make the safe distance maximize.

2. In the implementation of the utility model, the claw-shaped gasket with the notch is arranged inside the bell mouth of the built-in movable groove, and the claw-shaped gasket is provided with the elastic claw which is bent inwards, so that the blocking effect on the falling arrester body is realized; meanwhile, the claw-shaped gasket with the notch is easily arranged in the appointed gasket mounting groove under the action of external force; in addition the flexible activity space of reserving of elasticity of packing ring movable groove then for the elastic claw, can be smoothly with the arrester body from supreme passing elastic claw to insulator internal portion down, a plurality of functions have been realized to one set of integrated configuration, design benefit, function are complete, have satisfied ageing arrester anti-drop and have changed the demand.

3. The utility model discloses an anti-falling mechanism is built-in by original external change, has solved the installation interference that external anti-falling mechanism and the structure of end outlet lead-out terminal produced for the part is simplified, the structure is pleasing to the eye, and has improved production efficiency.

Drawings

FIG. 1 is a structural diagram of the lightning protection and fusing combination device of the present invention;

FIG. 2 is a structural view of the main body of the insulator of the present invention;

FIG. 3 is a schematic view of the lower end mounting structure of the fuse of the present invention;

FIG. 4 is a view of the structure of the lower end fixing member of the present invention;

fig. 5 is a structural diagram of the arrester body of the present invention;

FIG. 6 is a view showing a structure of the bell mouth of the present invention;

FIG. 7 is a cross-sectional view of the flare of FIG. 6;

FIG. 8 is a view of the structure of the claw washer of the present invention;

fig. 9 is a structural view of the lightning arrester body of the present invention installed in situ;

fig. 10 is a state diagram of the lightning arrester of the present invention with its body detached;

fig. 11 is a structural view of the mounting ring in the bell mouth in a state where the arrester body is detached;

the reference numbers are as follows: 1-an insulator body; 2-a bellmouth main body; 3-a lightning arrester body; 4-a fuse; 101-umbrella skirt; 102-an insulating tube; 103-lower opening of the insulating tube; 104-external thread; 105-an upper end fixture; 106-lower end fixing piece; 107-a fixture; 108-a magnet adsorption block; 109-set screws; 110-fuse fixing holes; 111-locating holes; 200-claw washer; 201-mounting screw threads; 202-gasket mounting groove; 203-gasket active groove; 204-a conductive contact surface; 205-a mounting ring; 206-mounting notches; 207-elastic claws; 208-a bump; 209-limit groove; 210-an elastic jaw portion; 301-an extension rod; 302-a lightning protection core; 303-a detaching unit; 304-a visor; 305-a conductive convex ring; 401-bolt; 402-fuse outlet terminal.

Detailed Description

An RW series drop-out fuse and an MOA series zinc oxide arrester are generally required to be installed at the offline position of a 10kV distribution network terminal to provide overcurrent and lightning protection for a distribution transformer, wherein A, B, C three phases are arranged at the input end of the 10kV distribution transformer, and three sets of lightning protection and fusing combination devices are arranged on a three-phase line.

The fuse adopts conventional drop-out fuse, and the drop-out fuse is the power equipment who possesses isolation and protection characteristic function that electric power industry is common, and the main characteristic is that when the current exceeded the fuse rated value, the fuse-element fuses with the heat that produces of itself, and inside fuse forms tension with falling the mechanism in the fusion tube, and when fuse-element fuse fuses and loses tension, falls the structure and utilizes gravity to fuse the fusion tube body with system power to form obvious disconnection distance.

The function of an arrester is an important device for protecting electrical equipment from high transient overvoltage. The lightning arrester is installed and connected between a power supply line and the ground, is usually used in parallel with protected equipment, does not release the ground when the power supply line or the equipment operates under normal rated working voltage, and is regarded as a high-resistance open-circuit state for the ground. Once high voltage occurs and the insulation of the protected equipment is endangered, the lightning arrester made of zinc oxide material releases overvoltage action to the ground immediately, and high voltage impact is guided to the ground, so that the voltage amplitude is limited, and the insulation of a power supply cable and the equipment is protected. When the overvoltage disappears, the lightning arrester is quickly restored to the original state, so that the power supply circuit works normally.

As the lightning arrester is used for a long time, the service life of the lightning arrester is inevitably in a long-term problem, and once the device is aged, the lightning arrester needs to be timely separated from a distribution network circuit. The general arrester separation mode can adopt a hot-melt type separation mode, the hot-melt type separator separates the grounding end of the zinc oxide arrester when the valve core in the zinc oxide arrester has aging fault, mainly shows that the current flowing through the valve plate is increased, so that the valve plate group forms a heating state, because the valve plate group has a negative temperature coefficient, the equivalent resistance caused by heating is reduced, the heating is accelerated, and vicious circle is formed, therefore, the working state of the zinc oxide arrester is directly transmitted to the separator in a temperature mode, the power frequency current is utilized to heat through the separator, when the temperature reaches the design value of the separator, the low-melting-point alloy is melted, and the separator acts to separate the zinc oxide arrester from the system grounding wire and then is replaced.

As shown in fig. 1-4, the lightning protection and fusing combination device of the present invention comprises a fuse 4, an insulator main body 1, a bell mouth main body 2 and a lightning arrester main body 3. The lightning arrester body 3 is installed inside the insulator main body 1, and the bell mouth main body 2 is connected to the mouth part at the lower end of the insulator main body 1 through threads.

In fig. 1, an upper end fixing member 105 is connected with the upper part of the insulator main body 1 and the upper part of the fuse 4, and the upper end fixing member 105 is connected with a high-voltage inlet end of an external power transmission line; the upper end fixing piece 105 is used as an upper end fixing part of the fuse, is provided with a mounting hole position and can be used for mounting a standard fuse; and is also the high-voltage incoming line end of the whole equipment.

As shown in fig. 3 and 4, the lower end fixing member 106 is connected to the lower portion of the insulator main body 1 and the lower portion of the fuse 4, and the lower end fixing member 106 serves as a fuse lower end fixing member and serves as a dual function of connecting a low-voltage outlet terminal and an inlet terminal of the surge arrester, and is connected to an input terminal of one of A, B, C three phases of an electric power device such as a transformer on the one hand and communicates with the lower end of the surge arrester main body 3 on the other hand.

One end of the lower end fixing member 106 is a straight end, and the other end is a ring-shaped end; wherein the straight end portion is provided with a fuse fixing hole 110 and is connected to a standard fuse and fuse outlet terminal 402 through a bolt 401; the annular end is sleeved on the lower opening 103 of the insulating tube, a positioning hole 111 is formed in the annular end, and the annular end is positioned at the set position of the lower opening 103 of the insulating tube through a positioning screw 109. The bell mouth main body 2 is fixed to the lower opening 103 of the insulating tube against the annular end of the lower end fixing member 106, and ensures electrical conduction between the lower end fixing member 106 and the bell mouth main body 2. The upper end fixing member 105 and the lower end fixing member 106 fix the fuse 4 and the insulator main body 1 in combination as an integrated device.

Insulator main part 1 is sealed barrel structure, and the middle part outer lane of insulator main part 1 is provided with mounting 107, mounting 107 and power equipment's earthing terminal and ground switch on mutually. An iron magnet adsorption block 108 is arranged in the cabin of the insulator main body 1, is fixedly connected with the fixing piece 107, and is used for adsorbing and fixing the lightning arrester body 3 at a set position in the insulator main body. The fixing part 107 is used as an external connecting part of the whole structure, one end of the part is provided with two connecting hole sites, and the fixing part can be fixed with a cross arm on a telegraph pole, so that the whole device is fixed through one cross arm; secondly, the grounding end of the lightning arrester is used as a connecting position; thirdly, the magnet absorption block 108 is connected to provide a firm fixing position for the magnet absorption block 108. The upper end of the arrester body 3 is attracted to the magnet attraction block 108 by magnetic force and is conducted with the fixing member 107. A magnet attracting surface is formed on the lower end surface of the magnet attracting block 108 to attract the magnet inside the detaching unit 303.

Insulator main part 1 includes sealed insulating tube 102 in upper end, and the full skirt main part 101 has been cup jointed to the outer lane of insulating tube 102, and insulating tube 102 adopts the fine pipe of glass to make, and full skirt main part 101 is pressed after with the silicon rubber vulcanization and is made on the insulating tube, and insulating tube end opening 103 outer lane is provided with the external screw thread for fixed hookup horn mouth main part 2. The bell mouth main body 2 is made of aluminum or other conductor materials, and the bell mouth main body 2 is fixed on the insulator main body 1 by the thread at the lower opening 103 of the insulating tube and is electrically communicated with the lower end fixing piece 106. The insulating tube 102 has threads, locating grooves and mounting holes formed therein to provide mounting locations for all of the structural components. A solid glass fiber rod is arranged in the insulating tube 102 on the upper part of the middle fixing piece 107, and the solid glass fiber rod has the first function of sealing and filling the upper end part of the insulating tube 102; second, the upper fixture 105 and the middle fixture 107 are prevented from conducting discharge.

When the lightning arrester is used, the whole lightning arrester body 3 is installed in the insulating tube 102, the magnet 313 adsorbs the lightning arrester body 3 to the magnet adsorption block 108, and at this time, the lightning arrester body 3 is grounded. The magnet attraction block 108 serves as a magnet attraction point, provides a reliable attraction force for the entire arrester body 3, and serves as an intermediate point for communicating the arrester body 3 with a ground wire. The metal conductive part of 3 lower extremes of arrester body can switch on with horn mouth

main part

2, and 3 completion high pressure inlet wire ends of arrester body are connected this moment, and 3 installations of whole arrester body are accomplished to this moment. The horn mouth main body 2 is structurally characterized in that the lower end is horn-shaped, and the structure is convenient for the installation of the lightning arrester body 3 and provides larger installation caliber and guiding function. The bell mouth main body 2 is made of aluminum, and a conductive layer is plated on the outer surface of the bell mouth main body to serve as an intermediate structure for communicating the lower end fixing member 106 with the arrester body 3.

As shown in fig. 5, the arrester body 3 includes a detachment unit 303, an arrester core 302 and an extension rod 301, which are arranged from top to bottom, and a cap peak 304 is arranged at an end of the detachment unit 303; an electrically conductive protruding ring 305 is arranged between the lightning protection core 302 and the extension rod 301. The inside magnet and other annexes that are provided with of unit 303 break away from, after the lightning-arrest core bears overvoltage or thunder and lightning emergence ageing trouble many times, break away from the unit inside and can begin to generate heat, finally make magnet lose magnetism for arrester body 3 drops naturally.

As shown in fig. 6 to 8, the exterior of the bell mouth main body 2 is of a bell mouth structure, the interior of the bell mouth main body is sequentially provided with an installation thread 201, a gasket installation groove 202, a gasket movable groove 203 and a conductive contact surface 204 from top to bottom, the installation thread 201 is matched with the external thread 104 at the lower part of the insulating tube in parameters, and the bell mouth main body 2 is fixed at the lower opening 103 of the insulating tube.

The gasket mounting groove 202 is used for fixing the claw type gasket 200, the protrusion 208 of the elastic claw 207 corresponds to the position of the gasket movable groove 203, the inner diameter and the width of the gasket movable groove 203 are both larger than the outer diameter of the protrusion 208, a movable space is reserved for the elastic part of the elastic claw 207 to ensure the telescopic function of the elastic claw, the upper surface of the limiting groove 209 is a conductive contact surface 204, and when the lightning arrester body is mounted in place, the conductive contact surface 204 is fully contacted with the conductive convex ring 305 on the lightning arrester body 3 for conduction.

The claw washer 200 comprises a mounting ring 205 and a plurality of elastic claws 207 arranged at the lower part of the mounting ring 205, the tops of the elastic claws 207 are fixedly connected with the mounting ring 205 into a whole, the elastic claws 207 are bent inwards and form a bulge 208 at the middle part, and the opening parts 210 of the elastic claws are of an outwards-opened structure, so that the lightning arrester body 3 can be conveniently assembled from the lower part. One side of collar 205 ring body is provided with installation breach 206, installation breach 206 run through whole ring body, installation breach 206's effect is for collar 205 provides the contraction structure, conveniently installs claw type packing ring 200 inside horn mouth main part 2.

In the mounting, in the first step, the mounting ring 205 of the claw washer 200 is held by hand so as to be partially overlapped at the mounting notch 206, and then the claw washer 200 is fixed inside the bell mouth body 2 from the lower portion of the bell mouth body 2 with the mounting ring 205 fixed at the position of the washer mounting groove 202. And secondly, fixedly connecting the bell mouth main body 2 to the lower part of the insulator main body 1 through threads. Thirdly, the arrester body 3 is installed from the lower part of the bell mouth main body 2, as long as the arrester body 3 is pushed upwards by force, the brim 304 of the arrester body 3 overcomes the elasticity of the claw-shaped gasket 200, and at the moment, the gasket movable groove 203 reserves an elastic space for the protrusion 208 of the elastic claw 207, so that the arrester body 3 is installed at a set position inside the insulator main body 1.

As shown in fig. 9, at this time, the top of the arrester body 3 is attracted to the magnet attraction block 108 disposed at the center of the insulator by the magnet inside the detachment unit 303, and the conductive contact surface 204 is fully contacted and conducted with the conductive convex ring 305 on the arrester body 3.

As shown in fig. 10 and 11, when the aged arrester body 3 falls off from the inside of the insulator main body 1, the visor 304 of the arrester body 3 is just caught on the protrusion 208 of the resilient claw 207, and the protrusion 208 provides resistance against the passage of the visor 304. Operating personnel uses the device cover at arrester body lower extreme, and it can make elastic claw 207 take place deformation to apply decurrent pulling force, makes brim of a hat 304 pass through horn mouth main part 2 to realize the dismantlement of arrester body 3, the step above the repetition again can be changed.

It should be noted that the utility model discloses an arrester can also use as the arrester alone except can combining into lightning-arrest fusing composite set with the fuse, connects the mounting 107 and the lower extreme mounting 106 of arrester in series on the lightning-arrest circuit can realize solitary lightning-arrest effect during the use. For those skilled in the art, based on the teachings of the present invention, changes, modifications, substitutions and variations can be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. The utility model provides a built-in arrester of preventing weighing down mechanism which characterized in that: the lightning arrester comprises an insulator main body (1), a bell mouth main body (2) and a lightning arrester body (3), wherein the lightning arrester body (3) is arranged inside the insulator main body (1) of a sealed cylinder structure, and the bell mouth main body (2) is connected to a lower opening (103) of an insulating tube at the lower end of the insulator main body (1); the outer ring of the top of the lightning arrester body (3) is provided with a cap peak (304); the novel lightning arrester is characterized in that a claw-shaped gasket (200) is arranged in the horn mouth main body (2), each claw-shaped gasket (200) comprises a mounting ring (205) and a plurality of elastic claws (207) arranged on the lower portion of the mounting ring (205), the top of each elastic claw (207) is fixedly connected with the mounting ring (205) into a whole, each elastic claw (207) bends inwards and forms a bulge (208) in the middle, and the bulges (208) can block the brim (304) when the lightning arrester body (3) falls.

2. The arrester with built-in anti-falling mechanism of claim 1, characterized in that: one side of the ring body of the mounting ring (205) is provided with a mounting notch (206), and the mounting notch (206) penetrates through the whole ring body.

3. The arrester with built-in anti-falling mechanism of claim 1, characterized in that: a gasket mounting groove (202) and a gasket movable groove (203) are arranged in the bell mouth main body (2) from top to bottom; the mounting ring (205) of the claw-shaped gasket (200) is mounted in the gasket mounting groove (202), and the gasket movable groove (203) corresponds to the position of the bulge (208) of the elastic claw (207).

4. The arrester with built-in anti-falling mechanism of claim 1, characterized in that: the lightning arrester is characterized in that a conductive convex ring (305) is arranged on the outer ring of the middle lower portion of the lightning arrester body (3), a limiting groove (209) is arranged inside the horn mouth main body (2), and a conductive contact surface (204) on the upper portion of the limiting groove (209) is in contact with the conductive convex ring (305) when the lightning arrester body (3) works normally.

5. The arrester with built-in anti-falling mechanism of claim 1, characterized in that: the outer ring of the insulator main body (1) is provided with a fixing piece (107).

6. The arrester with built-in anti-falling mechanism according to claim 5, characterized in that: a magnet adsorption block (108) is arranged in the insulator main body (1), and the magnet adsorption block (108) is fixed on the fixing piece (107).

7. The arrester with built-in anti-falling mechanism according to claim 6, characterized in that: the inside of the separation unit (303) at the upper end of the lightning arrester body (3) is provided with a magnet which is adsorbed with the magnet adsorption block (108).

8. The arrester with built-in anti-falling mechanism according to claim 1, characterized in that: the insulator main body (1) comprises an insulating tube (102) with the upper end sealed, an umbrella skirt main body (101) is sleeved on the outer ring of the insulating tube (102), and a lower opening (103) of the insulating tube is formed in the lower end of the umbrella skirt main body (101).

9. A lightning protection and fusion combination device with a built-in anti-falling mechanism, which is characterized by comprising a fuse protector and the lightning protector with the built-in anti-falling mechanism of any one of claims 1 to 8, wherein an upper end fixing piece (105) is connected with the upper parts of the insulator main body (1) and the fuse protector (4), and the upper end fixing piece (105) is connected with a high-voltage incoming line end of an external power transmission line.

10. A lightning protection fusing combination device with an internal fall protection mechanism according to claim 9, wherein: the lower parts of the insulator main body (1) and the fuse (4) are connected with a lower end fixing piece (106), and the lower end fixing piece (106) is fixed between the lower opening (103) of the insulating tube and the bell mouth main body (2).