CN217061995U - Alloy type thermal link with metal cover plate - Google Patents

Abstract

The utility model provides an alloy type thermal link who has metal covering plate. The thermal fuse link is characterized in that a central cavity or an irregular central cavity is arranged in the middle of a shell, a right end sealing cavity and a left end sealing cavity are respectively arranged at two ends of the shell, cover plates are arranged at two ends or one end of the central cavity and the irregular central cavity, two ends of a thermal element are respectively welded with a lead, the outer surface of the thermal element is wrapped with fluxing agent, the lead extends to the outside of the shell through a lead hole in the cover plate, and the right end sealing cavity and the left end sealing cavity are sealed by epoxy resin glue. Before the thermal element is welded, one end of the lead is struck or punched into a flat shape, and then welded to the thermal element. According to the thermal fuse link, the metal cover plate is additionally arranged between the thermal element and the epoxy resin adhesive, and the direct burn of high-temperature flame formed at the fusing moment of the thermal element of the thermal fuse link to the epoxy resin adhesive is prevented by utilizing the quick heat absorption performance of the metal cover plate.

Description

Alloy type thermal link with metal cover plate

Technical Field

The utility model relates to the thermal link field, in particular to alloy type thermal link who has metal cover plate.

Background

At present, current high-power domestic heating electrical apparatus when using, domestic heating electrical apparatus can rapid heating up under the circuit abnormal conditions, when the unusual temperature rise of heating electrical apparatus reaches a definite value, will influence whole high-power domestic heating electrical apparatus's normal work, can lead to high-power domestic heating electrical apparatus to fire the burning when serious. The working principle of the thermal fuse link is as follows: the heat energy of the household heating appliance is conducted to the shell of the thermal fuse link, the shell conducts the heat energy to the thermal element and the fluxing agent through epoxy resin glue, a lead and the like, the thermal element is fused under the action of the fluxing agent after being heated, and the power supply of a circuit is cut off, so that the household heating appliance is protected to prevent accidents or fires. When a temperature-sensitive thermal element is fused in a high-temperature and high-current environment, an electric arc is formed between two leads in a shell, the electric arc can directly act on epoxy resin glue at a shell opening to cause the performance of the epoxy resin glue to be instantly reduced, and when the adhesive force of the epoxy resin glue and the leads is reduced, molten liquid thermal element material and molten fluxing agent overflow along the joint surface of the leads and the epoxy resin glue, so that the electrical safety of the whole thermal fuse link is not guaranteed.

The patent number 201210096329.3, the patent name is the invention patent of temperature fuse, its main technical characteristics are: a fusible part: a first lead conductor and a second lead conductor extending from both ends of the fusible portion, respectively; a first stepped portion formed on the first lead conductor and a second stepped portion formed on the second lead conductor; a cylindrical case in which the fusible parts, the first lead conductor, and the second lead conductor are inserted from an opening at one end thereof, and the fusible parts are accommodated in a state in which end portions of the first lead conductor and the second lead conductor are led out to the outside; convex part: the first lead conductor is formed on the inner surface near the other end of the shell and used for clamping the first lead conductor; and a cover body which is sleeved on the second lead conductor and is clamped by the second step part.

Disclosure of Invention

An object of the utility model is to provide an alloy type thermal link who has metal covering plate. The utility model discloses the required technical problem who solves is: the metal cover plate is additionally arranged in the shell of the thermal fuse link, so that the instant burn of an electric arc formed when the thermal fuse link is fused under a high-temperature and high-current environment to the epoxy resin adhesive in the shell is prevented, and the fused liquid thermal element material is prevented from overflowing from the thermal fuse link; the product percent of pass of the thermal link during batch production is greatly improved, and 100 percent of the thermal link in batch production reaches the current standard of the thermal link issued by the state.

The design idea of the utility model is that: 1. a metal cover plate is added between the thermal element and the epoxy resin adhesive, and the direct burning of the epoxy resin adhesive by high-temperature flame formed at the fusing moment of the thermal element of the thermal fuse link is prevented by utilizing the quick heat absorption performance of the metal cover plate; 2. the quick heat-conducting property of the metal cover plate is utilized to absorb the heat energy released by a thermal element of a part of thermal link due to arc discharge at the fusing moment, so that the temperature in the shell of the thermal link is prevented from being quickly raised at the moment, and the thermal link is protected from being damaged by high pressure formed by gas expansion in the shell; 3. the metal cover plate is made of metal materials which are convenient to punch and form and good in heat conductivity, such as copper sheets, silver sheets and the like, the effect of tin plating, silver plating and the like on the outer side of the copper sheets is better, meanwhile, the tiny thermal element liquid particles splashed due to arc striking when the thermal fuse-link is fused can be adsorbed on the surface of the metal cover plate by utilizing the mutual fusibility of a tin plating layer on the outer side of the metal cover plate and tin contained in the thermal fuse-link thermal element, the risk that the splashed tiny thermal element liquid particles participate in conductive arc striking again is reduced, and the thermal fuse-link is protected from being damaged due to continuous arc striking; 4. according to the current of the thermal fuse-link product in a using circuit, the thickness of the metal cover plate is controlled, and the phenomenon that the temperature of the metal cover plate is too high after absorbing the heat energy of arc discharge due to insufficient heat capacity is prevented, so that the rapid temperature rise of epoxy resin glue cannot be effectively slowed down; 5. the shape of the metal cover plate can be made into a round shape, a square shape and the like, and can also be made into a multi-claw shape such as eight claws and the like, and the operation and use effects of the eight-claw shape are better; 6. the installation direction of the metal cover plate can be designed to be installed from the left side and the right side of the shell to the center of the shell simultaneously, and can also be designed to be installed from the right side of the shell; 7. The structure of the shell can be designed to simultaneously use two metal cover plates, and can also be designed to use the metal cover plates and protect the shell by using the material of the shell; 8. the shell is made of 95 ceramics or plastic with good heat conduction, insulation and temperature resistance, and the shell is round or square; 9. the front ends of the two lead wires are close to the thermal element, the lead wires are beaten or stamped into a flat shape, so that the inconsistency of fusing performance of the thermal element caused by the direct contact of the metal cover plate and the thermal element is prevented, and meanwhile, the thermal element can be ensured to be always positioned in the central part in the shell.

In order to achieve the above purpose, the technical scheme of the utility model is that:

an alloy type thermal fuse with a metal cover plate, comprising: casing, lead wire, hot component, fluxing agent, apron, epoxy glue, center chamber, right-hand member sealed chamber, pin hole, through-hole, left end sealed chamber and special-shaped center chamber, the thermal link be provided with center chamber or special-shaped center chamber at the middle part of casing, the both ends of casing are provided with right-hand member sealed chamber and left end sealed chamber respectively, be equipped with the apron at center chamber, special-shaped center chamber's both ends or one end, the both ends of hot component are welded with the lead wire respectively, the surface parcel of hot component has the fluxing agent, the lead wire extends to the outside of casing through the pin hole in the apron, right-hand member sealed chamber and left end sealed chamber are sealed with epoxy glue.

Before the lead wire in the thermal fuse body is welded with the thermal element, one end of the lead wire is beaten or punched into a flat shape, and then the lead wire is welded with the thermal element.

The casing of the thermal fuse link is circular or rectangular in shape, the central cavity or the special-shaped central cavity arranged in the casing is circular or rectangular, the inner diameter of the central cavity or the special-shaped central cavity is smaller than that of the right end sealing cavity and not larger than that of the left end sealing cavity, and the aperture of the through hole is smaller than that of the left end sealing cavity, so that bosses are formed at two ends of the central cavity or the special-shaped central cavity.

The center of the cover plate of the thermal fuse link is provided with a lead hole, the shape of the lead hole is any one of circular, square, eight-claw or multi-claw shape, the thickness of the cover plate is changed along with the characteristic requirement of the thermal fuse link, and the cover plate is made of metal materials which are convenient to punch and form and have good heat conductivity.

One end of a special-shaped central cavity arranged in the shell of the thermal fuse link is provided with a through hole, and the lead extends to the outside of the shell through the through hole.

The size, shape and thickness of the thermal fuse inner cover plate change along with the shape of the shell, and the cover plate is installed from the left end and the right end of the shell or is sequentially installed from the right end of the shell.

Compared with the prior art, the beneficial effects of the utility model reside in that:

1. according to the thermal fuse link, the metal cover plate is additionally arranged between the thermal element and the epoxy resin adhesive, and the direct burning of the epoxy resin adhesive by high-temperature flame formed at the fusing moment of the thermal element of the thermal fuse link is prevented by utilizing the quick heat absorption performance of the metal cover plate;

2. the thermal link absorbs heat energy released by a thermal element of a part of the thermal link due to arc discharge at the fusing moment by utilizing the quick heat conduction performance of the metal cover plate, so that the temperature in the shell of the thermal link is prevented from being quickly raised at the moment, and the thermal link is protected from being damaged by high pressure formed by gas expansion in the shell;

3. the thermal fuse metal cover plate is made of metal materials which are convenient to punch and form and good in heat conductivity, such as copper sheets, silver sheets and the like, and the effect of plating tin, silver and the like on the copper sheets is better;

4. the thermal fuse controls the thickness of the metal cover plate according to the current of the thermal fuse product in a using circuit, and prevents the metal cover plate from being heated too high after absorbing the heat energy of arc discharge due to insufficient heat capacity, so that the rapid temperature rise of the epoxy resin adhesive can not be effectively slowed down;

5. the shape of the metal cover plate arranged on the thermal fuse link can be made into a round shape, a square shape and the like, and can also be made into an eight-claw shape or a multi-claw shape, so that the eight-claw shape has better operation and use effects;

6. the installation direction of the metal cover plate can be designed to be installed from the left side and the right side of the shell to the center of the shell simultaneously, and can also be designed to be installed from the right side of the shell;

7. the shell structure of the thermal fuse link can be designed to simultaneously use two metal cover plates, and can also be designed to use the metal cover plate on the right side and protect the shell on the left side by using the material of the shell;

8. by adopting the thermal link body produced in batch with the structure, 100% of the produced thermal link body can reach the current standard of the thermal link body issued by the state, and 100% of products of the thermal link body in batch production are ensured to be qualified.

Drawings

FIG. 1 is a schematic structural diagram of a bi-metal cover plate thermal link mounted on two sides of a main view;

FIG. 2 is a schematic view of a thermal fuse link housing with a bi-metal cover plate mounted on both sides in a cross-sectional view;

FIG. 3 is a schematic left-view structural diagram of a circular housing of a bimetal cover thermal fuse;

FIG. 4 is a schematic left-view structural diagram of a square housing of a bimetal cover plate thermal fuse-link;

FIG. 5 is a schematic front view of a circular metal cover plate of the thermal fuse;

FIG. 6 is a schematic left sectional view of a thermal fuse circular metal cover plate;

FIG. 7 is a schematic front view of the thermal fuse eight-claw metal cover plate;

FIG. 8 is a schematic left sectional view of the thermal fuse eight-claw metal cover plate;

FIG. 9 is a schematic front view of a thermal fuse five-claw metal cover plate;

FIG. 10 is a schematic view of the lead, the thermal element and the flux;

FIG. 11 is a schematic diagram of the main sectional structure of the thermal fuse-link with a bimetal cover plate installed on the right side;

FIG. 12 is a schematic top sectional view of the thermal fuse link housing with the bimetallic cover mounted to the right;

FIG. 13 is a schematic view of the main cross-sectional structure of the thermal fuse link of a single metal cover plate;

fig. 14 is a schematic top sectional view of a thermal fuse link housing with a single metal cover.

In the figure: 1. the device comprises a shell, 2, leads, 3, a thermal element, 4, fluxing agent, 5, a cover plate, 6, epoxy resin glue, 7, a central cavity, 8, a right end sealing cavity, 9, lead holes, 10, a through hole, 11, a left end sealing cavity, 12 and a special-shaped central cavity.

Detailed Description

The technical solution of the present invention will be further clearly and completely described with reference to the accompanying drawings and examples.

Referring to fig. 1-14, the thermal fuse link is provided with a central cavity 7 or a special-shaped central cavity 12 in the middle of a housing 1, a right end sealing cavity 8 and a left end sealing cavity 11 are respectively arranged at two ends of the housing 1, a cover plate 5 is arranged at two ends or one end of the central cavity 7 or the special-shaped central cavity 12, two ends of a thermal element 3 are respectively welded with leads, the outer surface of the thermal element 3 is wrapped with a fluxing agent 4, the leads 2 extend to the outside of the housing 1 through lead holes 9 in the cover plate 5, and the right end sealing cavity 8 and the left end sealing cavity 11 are sealed by epoxy resin glue 6.

One end of the lead wire 2 in the thermal fuse is struck or punched into a flat shape before being welded to the heat element 3, and then welded to the heat element 3.

The casing 1 of the thermal fuse link is circular or rectangular in shape, the central cavity 7 or the special-shaped central cavity 12 arranged in the casing 1 is circular or rectangular, the inner diameter of the central cavity is smaller than that of the right end sealing cavity 8 and not larger than that of the left end sealing cavity 11, and the aperture of the through hole 10 is smaller than that of the left end sealing cavity 11, so that bosses are formed at two ends of the central cavity 7 or the special-shaped central cavity 12.

The center of the cover plate 5 of the thermal fuse link is provided with a lead hole 9 in any one of a circular shape, an eight-claw shape or a multi-claw shape, the thickness of the cover plate 5 is changed along with the characteristic requirement of the thermal fuse link, and the cover plate 5 is made of a metal material which is easy to punch and form and has good thermal conductivity.

One end of a special-shaped central cavity 12 arranged in a shell 1 of the thermal fuse link is provided with a through hole 10, a lead 2 extends to the outside of the shell 1 through the through hole 10, and the special-shaped central cavity 12 can be arranged in a round shape, a square shape and the like.

The size, shape and thickness of the cover 5 in the thermal fuse vary with the shape of the case 1, and the cover 5 is installed from both left and right ends of the case 1 or sequentially installed from the right end of the case 1.

Example one

The condition that the bimetal cover plate is installed from the two ends of the shell

Before the thermal link is assembled, different types of dies are selected according to the environment and the installation size of the thermal link, a central cavity 7 is punched in a shell 1, a right end sealing cavity 8 and a left end sealing cavity 11 are punched at two ends of the shell 1, the inner diameters of the right end sealing cavity 8 and the left end sealing cavity 11 are larger than that of the central cavity 7, and bosses are formed at two ends of the central cavity 7. Before the two leads 2 are soldered to the heat element 3, one ends of the two leads 2 are struck or punched into a flat shape, the two leads are soldered to the heat element 3, flux 4 is applied to the outside of the soldered heat element 3, the heat element 3 with the flux 4 applied thereto and the leads 2 are fed into the central cavity 7 through the right end sealing cavity 8, and the other ends of the leads 2 are led out of the left end sealing cavity 11. Two cover plates 5 are respectively sleeved on bosses at two ends of the central cavity 7 from the left lead wire 2 and the right lead wire 2, so that the heating element 3 arranged in the central cavity 7 cannot move. And finally, injecting the prepared epoxy resin adhesive 6 into a right end sealing cavity 8 and a left end sealing cavity 11 at two ends of the shell 1 to seal the installed lead 2.

When the surface temperature of the heating plate is rapidly increased due to an abnormality of the circuit in use, the temperature of the thermal link in direct contact with the outer surface of the heating plate is increased, the absorbed thermal energy is conducted to the heat element 3, and when the temperature of the heat element 3 is increased to the rated operating temperature, the heat element 3 is rapidly fused with the aid of the melted flux 4. The shell 1 prevents the direct burning of the epoxy resin adhesive 6 by high-temperature flame formed at the moment of fusing of the thermal element 3 of the thermal fuse body by utilizing the rapid heat absorption performance of the installed metal cover plate 5, thereby avoiding the occurrence of the overflow condition of the fused thermal element 3 along the lead after the epoxy resin adhesive 6 is burned by the high-temperature flame and achieving the purpose of protecting the circuit safely.

Example two

The condition that the bimetal cover plate is installed from the right end of the shell

Before the thermal fuse-link is assembled, according to the environment and installation size of the thermal fuse-link, different types of dies are selected, a special-shaped central cavity 12 is punched in a shell 1, a right end sealing cavity 8 is punched at the right end of the shell 1, a left end sealing cavity 11 is punched at the left end, the inner diameter of the right end sealing cavity 8 is larger than that of the special-shaped central cavity 12, the inner diameter of the left end sealing cavity 11 is larger than that of a through hole 10, the diameter of the through hole 10 is smaller than that of the special-shaped central cavity 12, and bosses are formed at two ends of the special-shaped central cavity 12. Before the two leads 2 are welded with the thermal element 3, one ends of the two leads 2 are beaten or punched into flat shapes, then the two leads are welded with the thermal element 3, then flux 4 is coated outside the welded thermal element 3, two cover plates 5 are respectively sleeved on two sides of the thermal element 3 from the left and right leads 2, finally the thermal element 3 coated with the flux 4, the leads 2 and the cover plates 5 are sent into a special-shaped central cavity 12 through a right end sealed cavity 8, the two cover plates 5 are installed on a boss, and the other ends of the leads 2 penetrate out of a left end sealed cavity 11. So that the heating element 3 housed in the shaped central cavity 12 does not move. And finally, injecting the prepared epoxy resin glue 6 into a right end sealing cavity 8 and a left end sealing cavity 11 at two ends of the shell 1 to seal the installed lead 2.

When the surface temperature of the heating plate is rapidly increased due to an abnormality of the circuit in use, the temperature of the thermal link in direct contact with the outer surface of the heating plate is increased, the absorbed thermal energy is conducted to the heat element 3, and when the temperature of the heat element 3 is increased to the rated operating temperature, the heat element 3 is rapidly fused with the aid of the melted flux 4. The shell 1 prevents the direct burning of the epoxy resin adhesive 6 by high-temperature flame formed at the moment of fusing of the thermal element 3 of the thermal fuse body by utilizing the rapid heat absorption performance of the installed metal cover plate 5, thereby avoiding the occurrence of the overflow condition of the fused thermal element 3 along the lead after the epoxy resin adhesive 6 is burned by the high-temperature flame and achieving the purpose of protecting the circuit safely.

EXAMPLE III

Installation of single metal cover plate

Before the thermal fuse-link is assembled, according to the environment and the installation size of the thermal fuse-link, different types of dies are selected, a special-shaped central cavity 12 is punched in a shell 1, a right end sealing cavity 8 is punched at the right end of the shell 1, a left end sealing cavity 11 is punched at the left end, the inner diameter of the right end sealing cavity 8 is larger than that of the special-shaped central cavity 12, the inner diameter of the left end sealing cavity 11 is larger than that of a through hole 10, the diameter of the through hole 10 is smaller than that of the special-shaped central cavity 12, bosses are formed at two ends of the special-shaped central cavity 12, and the through hole 10 is formed at the left end of the special-shaped central cavity 12. Before the two leads 2 are soldered to the heat element 3, one ends of the two leads 2 are struck or punched into a flat shape, the two leads are soldered to the heat element 3, flux 4 is applied to the outside of the soldered heat element 3, the heat element 3 with the flux 4 applied thereto is fed into the irregularly shaped central cavity 12 through the right end sealing cavity 8, and the other ends of the leads 2 are led out of the left end sealing cavity 11 through the through holes 10. A cover plate 5 is mounted on a boss at the right end of the shaped central cavity 12 from the right end of the housing 1 along the lead 2 through the right end seal cavity 8 so that the heat element 3 mounted in the shaped central cavity 12 does not move. And finally, injecting the prepared epoxy resin adhesive 6 into a right end sealing cavity 8 and a left end sealing cavity 11 at two ends of the shell 1 to seal the installed lead 2.

When the surface temperature of the heating plate is rapidly increased due to the abnormality of the circuit in use, the temperature of the thermal link directly contacting with the outer surface of the heating plate is increased, the absorbed thermal energy is conducted to the heat element 3, and when the temperature of the heat element 3 is increased to the rated operation temperature, the heat element 3 is rapidly fused with the aid of the melted flux 4. The shell 1 prevents the direct burn of the epoxy resin glue 6 by the high-temperature flame formed at the moment of fusing of the thermal element 3 of the thermal fuse body by utilizing the rapid heat absorption performance of the metal cover plate 5 and the boss at the left end of the special-shaped central cavity 12, thereby avoiding the occurrence of the condition that the fused thermal element 3 overflows along the lead after the epoxy resin glue 6 is burnt by the high-temperature flame and achieving the purpose of protecting the circuit safely.

Results of example testing

Test 1:

the product model is as follows: 130 ℃, 250V, 2A, test product quantity: 50 branches;

the test conditions are as follows: testing voltage: ac 275V, test current: ac 3A, voltage frequency: 50 Hz.

And (3) test results: 1. the actual fusing temperature of the product is 127 +/-0.3 ℃.

2. Visual inspection shows that the product has complete appearance, no damage, no lead falling, no heat element and no flux overflow from the casing.

Test 2:

the product model is as follows: 140 ℃, 250V, 2A, test product quantity: 50 branches;

the test conditions are as follows: testing voltage: ac 275V, test current: ac 3A, voltage frequency: 50 Hz.

And (3) test results: 1. the actual fusing temperature of the product is 135 +/-0.3 ℃.

2. Visual inspection shows that the product has complete appearance, no damage, no lead falling, no heat element and no flux overflow from the casing.

Test 3:

the product model is as follows: 125 ℃, 250V, 2A, test product quantity: 50 pieces

The test conditions are as follows: testing voltage: ac 275V, test current: ac 3A, voltage frequency: 50 Hz.

And (3) test results: 1. the actual fusing temperature of the product is 121 +/-0.3 ℃.

2. Visual inspection shows that the product has complete appearance, no damage, no lead falling, no heat element and no flux overflow from the casing.

From the three sets of experimental data above, it can be seen that: the metal cover plate is added in the shell of the alloy type thermal fuse link, so that the fused thermal element can be effectively prevented from overflowing outwards along the combination position of the epoxy resin glue and the lead, the gas pressure in the shell at the moment of fusing the thermal element can be effectively reduced, the shell is prevented from being broken, the safe and leakage-free fusing of the thermal fuse link is realized, and the power utilization safety of household appliances is better protected.

The above description is only a non-limiting embodiment of the present invention, and many embodiments can be derived, and it will be apparent to those skilled in the art that many modifications and improvements can be made without departing from the inventive concept and without making creative efforts, and these embodiments are all within the protection scope of the present invention.

Claims (6)

1. An alloy type thermal fuse with a metal cover plate, comprising: casing (1), lead wire (2), heat element (3), fluxing agent (4), apron (5), epoxy glue (6), central chamber (7), right-hand member sealed chamber (8), pin hole (9), through-hole (10), left end sealed chamber (11) and dysmorphism central chamber (12), its characterized in that: the thermal fuse link is characterized in that a central cavity (7) or a special-shaped central cavity (12) is arranged in the middle of a shell (1), a right end sealing cavity (8) and a left end sealing cavity (11) are respectively arranged at two ends of the shell (1), cover plates (5) are arranged at two ends or one end of the central cavity (7) or the special-shaped central cavity (12), two ends of a thermal element (3) are respectively welded with a lead (2), a fluxing agent (4) wraps the outer surface of the thermal element (3), the lead (2) extends to the outside of the shell (1) through a lead hole (9) in the cover plate (5), and the right end sealing cavity (8) and the left end sealing cavity (11) are sealed by epoxy resin glue (6).

2. An alloy type thermal fuse having a metal cover plate according to claim 1, wherein: the lead wire (2) in the thermal fuse body is formed by striking or punching one end of the lead wire (2) into a flat shape before the thermal element (3) is welded, and then welding the lead wire with the thermal element (3).

3. An alloy type thermal fuse with a metal lid plate according to claim 1, wherein: the appearance of the shell (1) of the thermal fuse is circular or rectangular, the central cavity (7) or the special-shaped central cavity (12) arranged in the shell (1) is circular or rectangular, the inner diameter of the central cavity is smaller than that of the right end sealing cavity (8) and not larger than that of the left end sealing cavity (11), the aperture of the through hole (10) is smaller than that of the left end sealing cavity (11), and bosses are formed at two ends of the central cavity (7) or the special-shaped central cavity (12).

4. An alloy type thermal fuse with a metal lid plate according to claim 1, wherein: the center of a cover plate (5) of the thermal fuse body is provided with a lead hole (9) which is in any one of a circular shape, an eight-claw shape or a multi-claw shape, and the cover plate (5) is made of a metal material which is easy to punch and form and has good heat conductivity.

5. An alloy type thermal fuse with a metal lid plate according to claim 1, wherein: one end of a special-shaped central cavity (12) arranged in a shell (1) of the thermal fuse body is provided with a through hole (10), and a lead (2) extends to the outside of the shell (1) through the through hole (10).

6. An alloy type thermal fuse having a metal cover plate according to claim 1, wherein: the size, shape and thickness of the cover plates (5) in the thermal fuse body are changed along with the shape of the shell (1), and the cover plates (5) are installed from the left end and the right end of the shell (1) or are sequentially installed from the right end of the shell (1).

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