CN111445658A

CN111445658A - Fire detector

Info

Publication number: CN111445658A
Application number: CN202010408529.2A
Authority: CN
Inventors: 洪尧祥; 黄金祥
Original assignee: Xiamen Set Electronics Co Ltd
Current assignee: Xiamen Set Electronics Co Ltd
Priority date: 2020-05-14
Filing date: 2020-05-14
Publication date: 2020-07-24
Anticipated expiration: 2040-05-14
Also published as: CN111445658B

Abstract

The present invention relates to fire detectors. The fire detector of the invention, including a outer casing and a fixed seat, there is a slideway on the fixed seat, also include: the bridge piece is provided with a constant limiting end and a releasable limiting end, and a low-melting-point alloy which is welded and fixed at the releasable limiting end, when the bridge piece is at an initial position or a triggering position, the bridge piece and two contact points of the first conductor and the second conductor are in a bridge connection state or an electric insulation state, so that the switching change is realized. The invention can be used for fire detection.

Description

Fire detector

Technical Field

The invention relates to a fire detector, in particular to a temperature-sensing fire detector adopting fusible metal as a temperature-sensing trigger material.

Background

The fire detector is one of the most important components of a fire detection system, which comprises at least one sensor capable of detecting various physical and chemical phenomena occurring during the combustion of a substance, either continuously or periodically with a certain frequency, and at least capable of providing a suitable signal to a control and indication device. Its basic function is to make effective response to the physical and chemical parameters of fire signals, such as various gases, smoke, heat and light (flame) generated during the combustion of matter, and to convert them into electric signals which can be received by computer for analysis and processing by computer.

The temperature-sensing fire detector is one of the more commonly used fire detectors, and is very suitable for some occasions which generate a large amount of heat and no smoke or a small amount of smoke, and have the defects of high dust, high humidity, smoke and water vapor retention and are not suitable for the smoke-sensing fire detector under normal conditions. The temperature sensing type fire detector especially the constant temperature type fire detector mainly includes: bimetallic fire detector, fusible metal fire detector and thermistor electronic fire detector.

The existing fusible metal type fire detector mainly utilizes a mechanism that after fusible metal sensitive to temperature is affected by high temperature of fire environment and is melted, a trigger component is driven to trigger a switch to generate an alarm signal. For example, CN204463348U, CN205680230U and CN208636979U are all based on that after the fusible metal melts or softens, the compressed return spring is released, thereby triggering the switch to generate the alarm switch signal. The structure of the fire detector is complicated due to the fact that the displacement trigger mechanism and the switch mechanism caused by temperature are two independent elements, and reliability is reduced.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a compact temperature-sensitive fire detector which integrates a displacement trigger mechanism and a switch mechanism caused by temperature into a whole.

The invention is realized by adopting the following technical scheme:

a fire detector comprises a shell with an inner space and a fixed seat arranged in the shell, wherein a slide way for a trigger slide rod to pass through is arranged on the fixed seat, and the fire detector also comprises:

a first conductor and a second conductor, the first conductor and the second conductor are fixed on the fixed seat respectively in an electric isolation way, and the ends of the first conductor and the second conductor at the same side are respectively provided with a contact head, the contact heads of the first conductor and the second conductor are used as two static contacts of the switch,

a bridging piece, which is provided with two abutting parts corresponding to the positions of the two contact points of the first conductor and the second conductor respectively, and is also provided with a through hole, so that the through hole can be sheathed on a trigger slide bar in a sliding way,

a compression elastic piece which is sleeved on a trigger sliding rod in a compression energy storage state,

a trigger slide bar, the trigger slide bar is positioned on the slide way of the fixed seat in a sliding way, the trigger slide bar is provided with a first end and a second end, the first end is a constant limiting end, the second end is a limit-releasing end, the compression elastic piece and the bridge piece are limited on the first position of the trigger slide bar by the constant limiting end and the limit-releasing end, the first position is an initial position,

a low melting point alloy welded and fixed on the releasable limiting end of the trigger slide bar,

when the low melting point alloy reaches the melting point of the low melting point alloy and is converted from a solid state into a liquid state, the limitation on the limit-removable end of the trigger slide bar can be removed, so that the elastic compression piece releases energy to push the bridging piece to slide to a second position on the trigger slide bar, namely a trigger position,

when the bridging piece is at the initial position or the triggering position, the bridging piece and two contact heads of the first conductor and the second conductor are in a bridging conduction state or an electric insulation state, so that switching change is realized.

In one embodiment, the first and second conductors are rods of metal conductors each having a step at one end to form the respective contact head.

In one embodiment, the bridging piece is a substantially "(" type structure of conductive material, the two ends of the bridging piece are the interference parts, and the middle part of the bridging piece is provided with the through hole.

In one embodiment, the trigger slide is a rod body having a substantially T-shaped cross-sectional axial surface, and has a hanging platform with one end serving as the constant restriction end and the other end serving as the releasable restriction end.

In one embodiment, the compression spring is a compression spring.

In one embodiment, the slide way of the fixing seat is a stepped hole through hole, and two ends of the compression spring respectively act between the bottom surface of the large stepped hole of the stepped hole through hole and the bridge piece.

In one embodiment, the fire detector is a normally closed switch, the hanging platform of the trigger slide bar abuts against the bottom end of the fixed seat, one side of the bridging piece is under the action of the elastic force of the compression spring, the other side of the bridging piece is limited by the low-melting-point alloy, the initial position of the triggering slide bar is a position in a bridging conduction state with two contact heads of the first conductor and the second conductor, and the triggering position of the triggering slide bar is a position in an electrical insulation state with the two contact heads of the first conductor and the second conductor.

In one embodiment, the low melting point alloy trigger device further comprises a compensation spring, wherein the compensation spring is sleeved on the trigger sliding rod in a compressed state and is arranged between the bridging piece and the low melting point alloy, and the elastic force of the compensation spring is greater than that of the compression spring.

In one embodiment, the fire detector is a normally open switch, the hanging platform of the trigger slide bar abuts against the bridging piece, one side of the bridging piece is under the action of the elastic force of the compression spring, the other side of the bridging piece is limited by the hanging platform of the trigger slide bar, the other end of the trigger slide bar passes through the slideway, is exposed out of the fixed seat and is limited by the low-melting-point alloy, the bridging piece is in a state of being electrically insulated from two contact heads of the first conductor and the second conductor at the initial position of the trigger slide bar, and the bridging piece is in a state of being bridged and conducted with the two contact heads of the first conductor and the second conductor at the trigger position of the trigger slide bar.

In one embodiment, the trigger slide bar further comprises a blocking piece which is sleeved on the limit-removable end of the trigger slide bar, and the low-melting-point alloy is used for welding and fixing the blocking piece on the limit-removable end of the trigger slide bar.

In one embodiment, the alloy further comprises a fluxing agent, and the fluxing agent covers the low-melting-point alloy.

In one embodiment, the flux-cored wire further comprises a protective layer, and the protective layer is coated on the outer surface of the flux-cored wire.

In one embodiment, the device further comprises a first conducting wire and a second conducting wire, wherein the first conducting wire and the second conducting wire are respectively connected with the first conductor and the second conductor and exposed out of the shell.

In one embodiment, the fixed seat is further provided with a flange structure for increasing creepage distance.

In one embodiment, the fixing seat further comprises a sealing glue for filling and sealing the opening of the outer shell to seal the fixing seat in the inner space of the outer shell.

By adopting the technical scheme, the displacement trigger mechanism and the switch mechanism caused by temperature can be integrated into a whole, the device has a more compact structure, and the use is more stable and reliable.

Drawings

FIG. 1 is a schematic sectional view of example 1;

FIG. 2 is a schematic sectional view of example 2;

FIG. 3 is an exploded view of the parts of example 2;

FIG. 4 is a schematic sectional view of example 3;

FIG. 5 is a schematic sectional view of example 4;

FIG. 6 is an exploded perspective view of the parts of example 4;

FIG. 7 is a schematic sectional view of example 5.

Detailed Description

To further illustrate the various embodiments, the invention provides the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the embodiments. Those skilled in the art will appreciate still other possible embodiments and advantages of the present invention with reference to these figures. Elements in the figures are not drawn to scale and like reference numerals are generally used to indicate like elements.

The invention will now be further described with reference to the accompanying drawings and detailed description.

Example 1:

as shown in fig. 1, this embodiment discloses a normally closed alloy type temperature-sensitive fire detector, which includes a casing 101 with an open end, and a sealing compound 102 filled in the opening of the casing 101 to form a space with a closed interior. A fixing base 105 made of insulating material is arranged in the space, three parallel through holes are arranged on the fixing base 105, and the through holes on two outer sides are pin mounting holes 1051. The two pin mounting holes 1051 are respectively fixedly mounted with a first spring leg 103 and a second spring leg 104, and the first spring leg 103 and the second spring leg 104 are used as two stationary contacts of the switch. The first spring leg 103 is connected with a first lead 112 and passes through the sealing compound 102 to be exposed out of the shell of the casing 101, and the second spring leg 104 is connected with a second lead 113 and passes through the sealing compound 102 to be exposed out of the shell of the casing 101. The first spring leg 103 and the second spring leg 104 are bars of conductive metal conductors, and each form a

step

1031 and 1041, respectively, to form corresponding contact heads. The contact heads of the first and

second spring legs

103 and 104 are in conductive contact via a bridge piece 106 for electrical connection.

In this embodiment, the through hole in the middle of the fixing seat 105 is a stepped hole through hole 1052, the stepped hole through hole 1052 serves as a sliding way for the trigger slide bar 107 to slide, and a trigger slide bar 107 having a hanging platform and having a T-shaped cross section along the axial surface is movably sleeved in the stepped hole through hole 1052 in the middle, and since the outer diameter of the hanging platform 1071 of the trigger slide bar 107 is larger than the inner diameter of the matching section of the stepped hole through hole 1052, the hanging platform 1071 of the trigger slide bar 107 cannot pass through. The hanging platform 1071 of the trigger sliding rod 107 may be an integral structure formed by flattening a rod at an end thereof, or may be formed by welding a block shaped like the hanging platform 1071 and a rod. The left side of the drawing in fig. 1 is defined as the top end, and the right side of the drawing is defined as the bottom end, so that the trigger slide bar 107 movably sleeved in the middle stepped hole through hole 1052 can only slide towards the bottom end in one direction. The bridge piece 106 is a substantially "(" type structure "conductive material sheet, and a through hole 1061 is formed in the middle portion thereof," ("type structure" conductive material sheet may have two end portions corresponding to the positions of the contact heads of the first and

second spring legs

103 and 104, respectively.

The bridge piece 106 is movably sleeved on the trigger slide bar 107 through a through hole 1061 thereof. Defining one end of the trigger slide bar 107 having the hanging platform 1071 as a lower end and the other opposite free end as an upper end, a breaking spring 108 in a compressed state is disposed in the large step hole of the step hole through hole 1052, the breaking spring 108 is also sleeved on the trigger slide bar 107 and guided and limited by the trigger slide bar 107, and both ends of the breaking spring 108 act between the bottom surface of the large step hole of the step hole through hole 1052 and the bridge piece 106. The opening spring 108 thus gives the bridge piece 106 the force to move away towards the first and

second spring legs

103, 104. A blocking piece 110 is provided with a sleeve hole, sleeved on the upper end of the trigger slide bar 107, and welded at the end of the trigger slide bar 107 through a low melting point alloy 111 (also called fusible alloy or fusible metal), and ensures that the blocking piece 110 can reliably press against the bridge piece 106 and can make the bridge piece 106 and the surfaces of the

steps

1031 and 1041 of the first and second

static spring legs

103 and 104 keep conductive contact with a certain pressure. Therefore, it is preferable that the bridging piece 106 is made of a conductive metal material having an elastic material, such as a copper sheet, an aluminum sheet, a copper alloy sheet, and the like, so that the bridging piece 106 can be used as both a conductor for connecting the first spring leg 103 and the second spring leg 104 and a spring for generating a downward pressure.

In addition, the embodiment can be used in the occasions with higher current and voltage, and in order to improve the insulation and voltage resistance of the product, a retaining edge 1053 is arranged at the contact position of the mounting points of the first and second

static spring feet

103 and 104 on the fixed seat 105 and the shell 101 so as to increase the creepage distance.

In this embodiment, the first spring leg 103 and the second spring leg 104 are fixed on the fixing base 105, and can be deformed to generate an extrusion force by increasing the form of the rivet point, so as to be more reliably fixed on the fixing base 105, and can be adhered and fixed by glue. The casing 101 may be made of metal or nonmetal, the metal material is preferably SPCC (generally cold rolled carbon steel), and the nonmetal material may be thermoplastic material, thermosetting material, ceramic material, etc. The first and

second spring legs

103, 104 may be made of copper-based wire, and the surface may be treated with tin plating and silver plating, and the bridge piece 106 may be made of metal conductive material and may have tin plating and silver plating on the surface. The fixing seat 105 can be made of thermoplastic materials, thermosetting materials and ceramic materials, preferably ceramic materials, so that the requirement of high-temperature impact is met, the materials are not obviously deformed, and the insulating property is good. The first conductive line 112 and the second conductive line 113 may be tin-plated copper lines or CP lines, and may also be added with an insulating layer. Preferably a multi-strand wire, with bending operability. In addition, if the first spring leg 103 and the second spring leg 104 are designed to be exposed out of the housing, the first lead 112 and the second lead 113 may be disconnected according to the requirement. The spring material of the opening spring 108 can be selected from SUS304, SUS631, GH 4169, GH 4145, Monel K500, Inconel 718, Inconel X750, and the like. The melting point of the low-melting-point alloy 111 is a predetermined temperature threshold, preferably below 232 ℃, and may be mainly composed of low-melting-point metal elements such as Bi, Sn, Pb, and In, and is changed from a solid state to a liquid state when the temperature reaches its melting point.

The temperature-sensitive fire detector of the embodiment is used as a switch device for sensing the temperature of the fire environment, and is connected into an electric circuit of a fire alarm system as a switch when the temperature-sensitive fire detector is used together with the system. Under the normal room temperature state, the low melting point alloy 111 keeps the baffle 110 fixed at the upper end position of the trigger slide bar 107, and the bridge piece 106 keeps the electrical connection with the first spring leg 103 and the second spring leg 104, and is in a normally closed state in an on-off state. Under the condition of fire, the low-melting-point alloy 111 is converted from a solid state to a liquid state due to the high environmental temperature, the baffle 110 is separated, the bridge piece 106 and the disconnecting spring 108 are not limited any more, the bridge piece 106 is driven to move towards the direction (upwards) in which the first spring foot 103 and the second spring foot 104 are far away under the action of the elastic force of the disconnecting spring 108, the electrical connection between the first spring foot 103 and the second spring foot 104 is driven to be disconnected, the switch state is an open state, and therefore an electric loop of a fire alarm system detects a fire signal and performs early warning and preventive measures.

The structural shapes of the above components of this embodiment can be realized by those skilled in the art in different shapes according to different applications and design requirements, and it is possible to adopt any schemes as long as the schemes can meet the characteristic requirements of the above description to realize the corresponding working principle.

In this embodiment, the structure formed by the first spring leg 103, the second spring leg 104, the bridge 106, the trigger slide 107 and the opening spring 108 has functions of both a displacement trigger mechanism and a switch mechanism, so that the structure is more compact and the use is more stable and reliable.

Example 2:

as shown in fig. 2 and 3, this embodiment discloses a normally closed alloy type temperature-sensitive fire detector, which includes a casing 101 with an open end, and a sealing compound 102 filled into the opening of the casing 101 to form a space with a closed interior. A fixing seat 105 is arranged in the space, three parallel through holes are arranged on the fixing seat 105, and the through holes on two outer sides are pin mounting holes 1051. The two pin mounting holes 1051 are respectively fixedly mounted with a first spring leg 103 and a second spring leg 104, and the first spring leg 103 and the second spring leg 104 are used as two stationary contacts of the switch. The first spring leg 103 is connected with a first lead 112 and passes through the sealing compound 102 to be exposed out of the shell of the casing 101, and the second spring leg 104 is connected with a second lead 113 and passes through the sealing compound 102 to be exposed out of the shell of the casing 101. The first spring leg 103 and the second spring leg 104 are metal conductors made of conductive materials, and are respectively provided with a step 1031 and a step 1041 to form corresponding contact heads. The contact heads of the first and

second spring legs

In this embodiment, the through hole in the middle of the fixing seat 105 is a stepped hole through hole 1052, and a trigger slide bar 107 having a hanging platform and having a T-shaped cross section along the axial surface is movably sleeved in the stepped hole through hole 1052 in the middle, and since the outer diameter of the hanging platform 1071 of the trigger slide bar 107 is larger than the inner diameter of the matching section of the stepped hole through hole 1052, the hanging platform 1071 of the trigger slide bar 107 cannot pass through. The left side of the drawing in fig. 1 is defined as the top end, and the right side of the drawing is defined as the bottom end, so that the trigger slide bar 107 movably sleeved in the middle stepped hole through hole 1052 can only slide towards the bottom end in one direction. The bridge piece 106 is a substantially "(" shaped "conductive material sheet with a through hole 1061 in the middle.

The bridge piece 106 is movably sleeved on the trigger slide bar 107 through a through hole 1061 thereof. Defining one end of the trigger slide bar 107 having the hanging platform 1071 as a lower end and the other opposite free end as an upper end, a compensation spring 109 in a compressed state is further sleeved between the upper end of the trigger slide bar 107 and the bridge piece 106, a baffle 110 having a sleeved hole is sleeved at the upper end of the trigger slide bar 107 and is welded at the end of the trigger slide bar 107 through a low melting point alloy 111 (also called fusible alloy or fusible metal), so that two ends of the compensation spring 109 act between the baffle 110 and the bridge piece 106. And a breaking spring 108 in a compressed state is arranged in the large step hole of the step hole through hole 1052, the breaking spring 108 is also sleeved on the trigger slide bar 107 and is guided and limited by the trigger slide bar 107, and two ends of the breaking spring 108 act between the bottom surface of the large step hole of the step hole through hole 1052 and the bridging piece 106. The opening spring 108 thus gives the bridge piece 106 the force to move away towards the first and

second spring legs

103, 104. The elastic force of the compensation spring 109 is greater than the elastic force of the opening spring 108, and because the suspension platform 1071 of the trigger slide bar 107 is unidirectionally restricted by the fixing base 105, and one end of the compensation spring 109 is restricted by the blocking piece 110, the other end of the compensation spring 109 overcomes the elastic force of the opening spring 108 and applies a force to the bridging piece 106, so that the bridging piece 106 is in conductive contact with the surfaces of the

steps

1031 and 1041 of the first and

second spring legs

103 and 104 with a certain pressure.

This example 2 adds a compensation spring 109 compared to embodiment 1. The inventor found in practical tests of example 1 that the bridge piece 106 of example 1 is no longer reliable in conductive contact with the

steps

1031 and 1041 of the first and

second spring legs

103 and 104 after a long period of use, the shock resistance of the product is poor, and the manufacturing difficulty is large because the low-melting-point alloy 111 is welded in a state that the bridge piece 106 is ensured to press the

steps

1031 and 104 of the first and

second spring legs

103 and 104. Therefore, through continuous improvement, the length of the trigger slide bar 107 is appropriately extended, and the compensation spring 109 is sleeved, so that the bridge piece 106 is ensured to be in reliable conductive contact with the

steps

1031 and 1041 of the first and

second spring legs

103 and 104 after a long period of use by the compensation spring 109, and thus the embodiment 2 has better shock resistance.

In addition, in this embodiment, in order to improve the dielectric withstand voltage capability of the product, the retaining edge 1053 is provided at the contact position between the mounting points of the first and

second spring legs

103 and 104 on the fixing base 105 and the housing 101, so as to increase the creepage distance.

second spring legs

103, 104 may be made of copper-based wire, and the surface may be treated with tin plating and silver plating, and the bridge piece 106 may be made of metal conductive material and may have tin plating and silver plating on the surface. The fixing seat 105 can be made of thermoplastic materials, thermosetting materials and ceramic materials, preferably ceramic materials, so that the requirement of high-temperature impact is met, the materials are not obviously deformed, and the insulating property is good. The first conductive line 112 and the second conductive line 113 may be tin-plated copper lines or CP lines, and may also be added with an insulating layer. Preferably a multi-strand wire, with bending operability. If the first spring leg 103 and the second spring leg 104 are designed to be exposed out of the housing, the first lead 112 and the second lead 113 may be selectively disconnected according to the requirement. The spring material of the opening spring 108 and the compensation spring 109 can be selected from SUS304, SUS631, GH 4169, GH 4145, Monel K500, Inconel 718, Inconel X750, and the like. The melting point of the low-melting-point alloy 111 is a predetermined temperature threshold, preferably below 232 ℃, and may be mainly composed of low-melting-point metal elements such as Bi, Sn, Pb, and In, and is changed from a solid state to a liquid state when the temperature reaches its melting point.

The temperature-sensitive fire detector of the embodiment is used as a switch device for sensing the temperature of the fire environment, and is connected into an electric circuit of a fire alarm system as a switch when the temperature-sensitive fire detector is used together with the system. Under the normal room temperature state, the low melting point alloy 111 keeps the baffle 110 fixed at the upper end position of the trigger slide bar 107, and the compensation spring 108 keeps the bridge piece 106 electrically connected with the first and second

static spring legs

103 and 104, and is in a normally closed state in a switch state. When a fire occurs, the low melting point alloy 111 is converted from a solid state to a liquid state due to the high environmental temperature, the baffle 110 is separated, when the compensation spring 109 loses support, pressure is not applied to the bridging piece 106 and the disconnecting spring 108 any more, the bridging piece 106 is driven to move towards the direction in which the first and

second spring feet

103 and 104 are far away under the action of the elastic force release of the disconnecting spring 108, the electrical connection between the first and

second spring feet

103 and 104 is driven to be disconnected, the switch state is an open state, and therefore an electric loop of the fire alarm system detects a fire signal, and early warning and preventive measures are taken.

This embodiment has the technical advantages of being more shock resistant and stable for a longer period of time in addition to the technical advantages of embodiment 1 described above.

Example 3:

as shown in fig. 4, this embodiment discloses a normally closed alloy type temperature sensitive fire detector, which is substantially the same as embodiment 2 described above, wherein the same reference numerals are used for the same components, except that: a layer of fluxing agent 112, such as rosin and the like, is added and covered on the low-melting-point alloy 111 in a certain amount, so that the embodiment can not only not reduce the insulation and voltage resistance of the product, but also improve the melting point precision of the low-melting-point alloy 111, thereby improving the reliability of the product. Additionally, in order to avoid the performance of the fusing aid 112 affected by the environment (such as softening or oxidation), the embodiment further covers a protective layer 113 on the outer surface of the fusing aid 112 for curing and sealing, such as an epoxy resin protective layer.

This embodiment has, in addition to the technical advantages of embodiment 2 described above, the technical advantage of more accurate and reliable trigger temperature.

Example 4:

as shown in fig. 5 and 6, the embodiment discloses a normally open alloy type temperature-sensitive fire detector, which includes a casing 201 with an open end, wherein the opening of the casing 201 is filled with a sealing compound 202 to form an inner closed space. A fixed seat is arranged in the space, and the fixed seat is formed by overlapping an upper fixed seat 211 and a lower fixed seat 205; two parallel through holes are arranged on the lower fixing seat 205 and serve as pin mounting holes 2051, the two pin mounting holes 2051 are respectively and fixedly provided with a first static spring foot 203 and a second static spring foot 204, and the first static spring foot 203 and the second static spring foot 204 serve as two static contacts of a switch. The first spring leg 203 is connected with a first lead 212 and passes through the sealing compound 202 to be exposed out of the shell 201, and the second spring leg 204 is connected with a second lead 213 and passes through the sealing compound 202 to be exposed out of the shell 201. The first and

second spring legs

203 and 204 are metal conductors made of conductive material, and each have a step 2031 and a step 2041 to form a corresponding contact head. After the upper fixing base 211 is overlapped with the lower fixing base 205, a space 215 is formed between the two in the opposite directions, a bridge piece 206 is disposed in the space 215, and the space 215 is sufficient to ensure that the bridge piece 206 can have a sufficient electrical insulation interval with the

steps

2031 and 2041 of the first and

second spring legs

203 and 204, so that the contact heads of the first and

second spring legs

203 and 204 can be displaced to a conductive bridging position by the bridge piece 206 to achieve electrical connection.

More specifically, the bridge piece 206 is a substantially "(" type structure of conductive material sheet, and the middle part thereof is provided with a through hole 2061, the middle of the upper fixing seat 211 is provided with a stepped hole through hole 2111, a trigger slide bar 207 with a hanging platform, which is substantially T-shaped along the cross section of the shaft surface, is movably sleeved in the middle stepped hole through hole 2111, the left side of the drawing surface in fig. 1 is defined as the top end, the right side of the drawing surface is defined as the bottom end, one end of the trigger slide bar 207 with the hanging platform 2071 is defined as the lower end, the opposite free end is the upper end, the bridge piece 206 is sleeved at the lower end of the trigger slide bar 207 through the through hole 2061 and abuts against the hanging platform 1, a compressed breaking spring 208 is arranged in the large stepped hole of the stepped hole through hole 2071, the breaking spring 208 is sleeved on the trigger slide bar 207, the triggering slide bar 207 is guided and limited, and the two ends of the breaking spring 208 respectively act on the large stepped hole through hole 2111 and the bridging piece 206 . The opening spring 208 thus provides the bridge piece 206 with a force to move toward the first and

second spring legs

203, 204. The upper end of the trigger slide bar 207 passes through the through hole 2111 of the stepped hole of the upper fixing seat 211 and is exposed out of the upper fixing seat 211, and a baffle plate 209 having a sleeving hole is sleeved on the upper end of the trigger slide bar 207 and welded to the upper end of the trigger slide bar 207 through a low melting point alloy 210 (also called fusible alloy or fusible metal), so that the trigger slide bar 207 is restricted to the upper fixing seat 211 and cannot slide. In this embodiment, in order to ensure that the baffle 209 and the low melting point alloy 210 have an installation space, the top end surface of the upper fixing seat 211 further has a convex pillar 2112 facing the top surface of the housing 201 to partition the installation space.

In addition, in this embodiment, a fence structure is formed at the outer periphery of the upper fixing seat 211 and the lower fixing seat 205 and at the contact position with the casing 101, so that the creepage distance can be increased, and the embodiment can be used in the occasions of higher current and voltage and has higher voltage insulation capability; in addition, the two parts are also matched with each other to form the space 215 for the displacement of the bridge piece 206.

In this embodiment, the first spring leg 203 and the second spring leg 204 are fixed on the lower fixing base 205, and can be deformed to generate an extrusion force by increasing the form of the rivet point, so as to be more reliably fixed on the lower fixing base 205, and can be fixed by adhesion through glue. The housing 201 may be made of metal or nonmetal, the metal material is preferably SPCC (usually cold rolled carbon steel), and the nonmetal material may be thermoplastic, thermosetting, or ceramic. The first and

second spring legs

203, 204 may be made of copper-based wire, and the surface may be treated with tin plating and silver plating, and the bridge piece 206 may be made of metal conductive material and may have tin plating and silver plating on the surface. The upper fixing seat 211 and the lower fixing seat 205 can be made of thermoplastic materials, thermosetting materials and ceramic materials, and the ceramic materials are preferred, so that the requirement of high-temperature impact is met, the materials are not obviously deformed, and the insulating property is good. The first conductive line 212 and the second conductive line 213 may be a tinned copper line or a CP line, and an insulating layer may be added. Preferably a multi-strand wire, with bending operability. The spring material of the opening spring 208 can be selected from SUS304, SUS631, GH 4169, GH 4145, Monel K500, Inconel 718, Inconel X750, and the like. The melting point of the low-melting-point alloy 210 is a predetermined temperature threshold, preferably below 232 ℃, and may be mainly composed of low-melting-point metal elements such as Bi, Sn, Pb, and In, and is changed from a solid state to a liquid state when the temperature reaches its melting point.

The temperature-sensitive fire detector of the embodiment is used as a switch device for sensing the temperature of the fire environment, and is connected into an electric circuit of a fire alarm system as a switch when the temperature-sensitive fire detector is used together with the system. Under the normal room temperature state, the low melting point alloy 210 keeps the blocking piece 209 fixed at the upper end position of the trigger slide bar 207, and the bridge piece 206 keeps the electrical isolation from the first spring leg 103 and the second spring leg 104, and is in a normally off state in the switch state. Under the condition of fire, the low-melting-point alloy 210 is converted from a solid state into a liquid state due to the high environmental temperature, the baffle plate 209 is separated, the bridge piece 206 and the disconnecting spring 208 are not limited any more, the bridge piece 206 is driven to move towards the direction (downwards) in which the first spring leg 203 and the second spring leg 204 are close to each other under the action of the elastic force of the disconnecting spring 208, the electrical connection between the first spring leg 203 and the second spring leg 204 is conducted, the switch state is a closed state, and therefore an electric loop of a fire alarm system detects a fire signal and performs early warning and preventive measures.

In this embodiment, the structure formed by the first spring leg 203, the second spring leg 204, the bridge piece 206, the trigger slide 207 and the opening spring 208 has functions of both a displacement trigger mechanism and a switch mechanism, so that the structure is more compact and the use is more stable and reliable.

Example 5:

as shown in fig. 7, this embodiment discloses a normally open type alloy type temperature sensitive fire detector, which is substantially identical to embodiment 4 described above, wherein the same reference numerals are used for the same components, except that: the upper fixing base 211 'in this embodiment is slightly different from the fixing base 211 of embodiment 4, the top end surface of the upper fixing base 211' does not have the convex column facing the top surface of the housing in embodiment 4, and the top end surface of the upper fixing base 211 'can be attached to the inner wall surface of the top surface of the housing 201'. In addition, the housing 201' of this embodiment is different from the housing 201 of the above embodiment 4, and the top surface of this embodiment has a through hole for the upper end of the trigger slide 207 to directly pass through, so that the low melting point alloy 210 can be directly welded and fixed to the upper end of the trigger slide 207 by the top surface of the housing 201 without using the baffle 209 to assist the welding and fixing as in the above embodiment. And, the first and

second spring legs

203 and 204 of this embodiment are designed to be exposed to the housing 201' more, so that the lower ends of the first and

second spring legs

203 and 204 can be used as external pins of the device without connecting the first and

second wires

212 and 213 of embodiment 4.

In addition, similar to the embodiment 3, a certain amount of fluxing agent 212, such as rosin, is added to the low melting point alloy 210, so that the embodiment can not only not reduce the dielectric strength of the product, but also improve the melting point accuracy of the low melting point alloy 210, thereby improving the reliability of the product. Additionally, in order to avoid the performance of the fusing aid 212 affected by the environment (such as softening or oxidation), the embodiment further covers a protective layer 213, such as an epoxy resin protective layer, on the outer surface of the fusing aid 212 for curing and sealing.

This embodiment has the advantages of more compact structure and more stable and reliable use due to the structure of the first spring leg 203, the second spring leg 204, the bridge piece 206, the trigger sliding rod 207 and the opening spring 208 of embodiment 4 having the functions of both the displacement trigger mechanism and the switch mechanism, and also has the advantages of reduced manufacturing cost and difficulty compared with embodiment 4 because the components such as the blocking piece, the first lead wire and the second lead wire are omitted. In addition, this embodiment has the additional technical advantage of the above-described embodiment 3 that the trigger temperature is more accurate and reliable.

It should be noted that, the compressed elastic element sleeved on the trigger slide bar in the above embodiments is shown by taking a breaking spring (compression spring) in a compressed state as an example, but those skilled in the art may also use other compressed elastic elements instead, such as a high-elasticity foam sponge sleeve, a disc spring, a plurality of elastic sheets arranged along the circumferential direction, and the like, which are feasible solutions.

While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. Fire detector, including a shell that has inner space and a fixing base of setting in this shell, its characterized in that is provided with the slide that supplies one to trigger the slide bar and pass on this fixing base, still includes:

2. A fire detector as claimed in claim 1, wherein: the first conductor and the second conductor are rods of metal conductors, one end of each rod is provided with a step to form the corresponding contact head.

3. A fire detector as claimed in claim 1, wherein: the bridging piece is a piece body made of conductive materials with a roughly' shaped structure, two ends of the bridging piece are the abutting parts, and the middle part of the bridging piece is provided with the through hole.

4. A fire detector as claimed in claim 1, wherein: the trigger slide bar is a bar body with a shaft surface section approximately in a T shape, one end of the trigger slide bar is a constant limiting end, and the other end of the trigger slide bar is a limit-releasing end.

5. A fire detector as claimed in claim 4, wherein: the compression spring is a compression spring.

6. A fire detector as claimed in claim 5, characterised in that: the slideway of the fixing seat is a stepped hole through hole, and two ends of the compression spring respectively act between the bottom surface of the large stepped hole of the stepped hole through hole and the bridging piece.

7. A fire detector as claimed in claim 6, characterised in that: the fire detector is a normally closed switch, the hanging platform of the trigger slide bar is abutted against the bottom end of the fixed seat, one side of the bridging piece is under the elastic action of the compression spring, the other side of the bridging piece is limited by the low-melting-point alloy, the initial position of the bridging piece at the trigger slide bar is in a bridging conduction state with two contact heads of the first conductor and the second conductor, and the trigger position of the bridging piece at the trigger slide bar is in an electrical insulation state with the two contact heads of the first conductor and the second conductor.

8. A fire detector as claimed in claim 7, wherein: the compensating spring is sleeved on the trigger sliding rod in a compressed state and is arranged between the bridging piece and the low-melting-point alloy, and the elasticity of the compensating spring is greater than that of the compression spring.

9. A fire detector as claimed in claim 6, characterised in that: the fire detector is a normally open switch, the hanging platform of the trigger slide bar is abutted to the bridging piece, one side of the bridging piece is under the elastic force action of the compression spring, the other side of the bridging piece is limited by the hanging platform of the trigger slide bar, the other end of the trigger slide bar penetrates through the slideway and is exposed out of the fixed seat and limited by the low-melting-point alloy, the initial position of the bridging piece on the trigger slide bar is in an electric insulation state with two contact heads of the first conductor and the second conductor, and the trigger position of the bridging piece on the trigger slide bar is in a bridging conduction state with the two contact heads of the first conductor and the second conductor.

10. A fire detector as claimed in claim 1, wherein: the trigger slide bar is sleeved with the releasable limiting end of the trigger slide bar, and the low-melting-point alloy is used for welding and fixing the blocking piece at the releasable limiting end of the trigger slide bar.

11. A fire detector as claimed in claim 1, wherein: the low-melting-point alloy is characterized by also comprising a fusing assistant agent, wherein the fusing assistant agent covers the low-melting-point alloy.

12. A fire detector as claimed in claim 11, wherein: the flux-cored wire also comprises a protective layer, and the protective layer is coated on the outer surface of the flux-cored wire.

13. A fire detector as claimed in claim 1, wherein: the first lead and the second lead are respectively connected with the first conductor and the second conductor and are exposed out of the shell.

14. A fire detector as claimed in claim 1, wherein: the fixed seat is also provided with a flange structure for increasing creepage distance.

15. A fire detector as claimed in claim 1, wherein: the sealing glue is used for filling and sealing the opening of the shell to seal the fixed seat in the inner space of the shell.