Fire Check Valve

Abstract

The present invention relates to a fire-proof check valve, which solves the problem of short service life of a temperature sensing mechanism. The fire-proof check valve comprises a valve body with an exhaust port, a valve plate and a connecting mechanism, wherein the connecting mechanism is used to connect the valve plate with the valve body and can drive the valve plate to close the exhaust port, and the fire-proof check valve also comprises a locking mechanism, a toggle mechanism, an elastic element and a temperature sensing mechanism, wherein the locking mechanism and the toggle mechanism are arranged on the valve body, and the locking mechanism has a locking position and an unlocking position, and when the locking mechanism is in the locking position, the temperature sensing mechanism is clamped between the locking mechanism and the valve body, and after the temperature sensing mechanism is actuated, the elastic element drives the locking mechanism to move from the locking position to the unlocking position through the toggle mechanism, and when the locking mechanism is in the unlocking position, the valve plate closes the exhaust port.

Description

Technical Field

[0001] The invention relates to a fire-proof check valve. Background Art

[0002] The existing fireproof check valve (the specific structure can refer to the invention patent with application number 201610651149.5) includes a valve seat, a lever, a temperature sensing mechanism and a torsion spring. The temperature sensing mechanism includes a first metal plate, a second metal plate and a fusible solder for connecting the first metal plate and the second metal plate. The lever and the second metal plate are rotatably connected to the valve seat, one torsion arm of the torsion spring is connected to the valve seat, and the other torsion arm of the torsion spring is connected to the lever and drives the lever to abut against the first metal plate. A limit piece is provided on the valve seat. When the other torsion arm of the torsion spring is connected to the lever and drives the lever to abut against the first metal plate, and the first metal plate and the second metal plate are connected by the fusible solder, the second metal plate abuts against the limit piece to achieve the temperature sensing mechanism being clamped between the lever and the limit piece.

[0003] When the temperature sensing mechanism is clamped between the lever and the limit member, the lever applies a first force to the first metal plate, and the limit member applies a second force to the second metal plate. The first force and the second force are of the same magnitude and opposite in direction. In other words, the first force keeps the first metal plate moving upward relative to the fusible solder, and the second force keeps the second metal plate moving downward relative to the fusible solder. Since the position where the lever abuts the first metal plate and the position where the limit member abuts the second metal plate are staggered, the fusible solder is subjected to torsional force for a long time.

[0004] The long-term torsional force acting on the fusible solder will cause the first metal plate (or the second metal plate) to separate from the fusible solder, which means that under normal temperature conditions, the temperature sensing mechanism of the fire check valve will automatically fail after a period of use. After the temperature sensing mechanism automatically fails, the torsion spring drives the lever to rotate relative to the valve seat, so that the lever drives the valve plate to close the exhaust port through the connecting rod. Summary of the invention

[0005] The problem to be solved by the present invention is to provide a fire-proof check valve to increase the service life of a temperature sensing mechanism.

[0006] To solve the above problems, the present invention provides the following technical solutions: a fire check valve comprises a valve body with an exhaust port, a valve plate and a connecting mechanism, the valve plate is made of metal, the connecting mechanism is used to connect the valve plate and the valve body and can drive the valve plate to close the exhaust port, the fire check valve also comprises a locking mechanism, a toggle mechanism, an elastic element and a temperature sensing mechanism, the locking mechanism and the toggle mechanism are arranged on the valve body, the locking mechanism has a locking position and an unlocking position, when the locking mechanism is in the locking position, the temperature sensing mechanism is clamped between the locking mechanism and the valve body, after the temperature sensing mechanism is actuated, the elastic element drives the locking mechanism to move from the locking position to the unlocking position through the toggle mechanism, when the locking mechanism is in the unlocking position, the valve plate closes the exhaust port.

[0007] Furthermore, the locking mechanism moves axially relative to the valve body so as to move it from a locked position to an unlocked position.

[0008] Furthermore, when the temperature sensing mechanism is clamped between the locking mechanism and the valve body, the temperature sensing mechanism is located on the outside of the valve body; or, the temperature sensing mechanism is located on the inside of the valve body; or, part of the temperature sensing mechanism is located on the outside of the valve body, and the remaining part of the temperature sensing mechanism is located on the inside of the valve body.

[0009] Further, after the temperature sensing mechanism is actuated, the toggle mechanism drives the valve plate to close the exhaust port through the connecting mechanism; or, after the temperature sensing mechanism is actuated, the toggle mechanism drives the valve plate to close the exhaust port.

[0010] Furthermore, a guide channel is provided on the valve body, and at least a part of the locking mechanism is arranged in the guide channel. When the locking mechanism is located at the locking position or the unlocking position, at least one end surface of the locking mechanism is located outside the guide channel.

[0011] Furthermore, the valve body includes an annular baffle plate, a guide hole is provided on the annular baffle plate, the guide hole is the guide channel, and the locking mechanism includes a locking rod, and the locking rod passes through the guide hole.

[0012] Furthermore, a fixing portion is provided at one end of the locking rod, and the temperature sensing mechanism is clamped between the fixing portion and the annular baffle.

[0013] Furthermore, the temperature sensing mechanism includes at least one solder ring sleeved on the locking rod, and the at least one solder ring is clamped between the fixing portion and the annular baffle.

[0014] Furthermore, the temperature sensing mechanism also includes a first metal plate, a second metal plate and a solder part for connecting the first metal plate and the second metal plate, the first metal plate is detachably arranged at the other end of the locking rod, and the second metal plate is provided with a stopper, when the locking mechanism is in the locking position, the stopper is engaged with the toggle mechanism to prevent the elastic element from driving the toggle mechanism to move relative to the valve body.

[0015] Furthermore, the height of the anti-rotation portion is less than the axial length of the solder ring.

[0016] Furthermore, the locking rod includes a screw, the fixing portion is the head of the screw, and the rod portion of the screw is fixedly connected to the first metal plate.

[0017] Furthermore, the temperature sensing mechanism also includes a solder rod, one end of which is clamped between the locking rod and the valve body, and the other end of the solder rod is provided with a stopper. When the locking mechanism is in the locking position, the stopper is engaged with the toggle mechanism to prevent the elastic element from driving the toggle mechanism to move relative to the valve body.

[0018] Beneficial effects of the present invention:

[0019] 1. In the present invention, the fire check valve includes a locking mechanism and a temperature sensing mechanism, and the temperature sensing mechanism is clamped between the locking mechanism and the valve body. In the prior art, the fire check valve needs to go through three steps to install the temperature sensing mechanism on the valve seat during the manufacturing process: step one, the temperature sensing mechanism is set on the valve seat through a fastener; step two, one side of the temperature sensing mechanism is against the limiter; step three, the other side of the temperature sensing mechanism is against the lever. In the present invention, the temperature sensing mechanism is first set on the locking mechanism, and then the temperature sensing mechanism is clamped between the locking mechanism and the valve body. Through the above two steps, the temperature sensing mechanism completes its installation steps. With such a design, by changing the installation position and installation structure of the temperature sensing mechanism, the installation steps of the fire check valve are simplified, the production efficiency of the fire check valve is improved, and the manufacturing cost of the fire check valve is reduced.

[0020] 2. In the present invention, the locking mechanism has a locking position and an unlocking position. After the temperature sensing mechanism is activated, the elastic element drives the locking mechanism to move from the locking position to the unlocking position through the toggle mechanism. After the fire check valve is replaced with a temperature sensing mechanism of different specifications, the locking position of the locking mechanism will change. With such a design, the position accuracy requirement of the locking mechanism can be appropriately reduced to reduce the manufacturing cost of the fire check valve.

[0021] 3. In the present invention, when the temperature sensing mechanism is clamped between the locking mechanism and the valve body, the temperature sensing mechanism is located on the outside of the valve body. This structure can enable the fire check valve to prevent smoke from entering the exhaust duct when a fire occurs indoors; when the temperature sensing mechanism is clamped between the locking mechanism and the valve body, the temperature sensing mechanism is located on the inside of the valve body. This structure can enable the fire check valve to prevent smoke from entering the room through the exhaust duct when a fire occurs outdoors; when the temperature sensing mechanism is clamped between the locking mechanism and the valve body, part of the temperature sensing mechanism is located on the outside of the valve body, and the remaining part of the temperature sensing mechanism is located on the inside of the valve body. This structure can enable the fire check valve to achieve dual smoke isolation both indoors and outdoors. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a three-dimensional diagram of a fire check valve in a preferred embodiment of the present invention;

[0023] Figure 2 is a bottom view of a fire check valve in a preferred embodiment of the present invention;

[0024] Figure 3 yes Figure 2 Sectional view at AA in the middle;

[0025] Figure 4 yes Figure 2 Cross-sectional view at the middle BB (locking mechanism in locked position);

[0026] Figure 5 yes Figure 2 Cross-sectional view at the middle BB (locking mechanism in unlocked position);

[0027] Figure 6 is a three-dimensional diagram of a locking mechanism and a temperature sensing mechanism in a preferred embodiment of the present invention;

[0028] Figure 7 is a cross-sectional view of a locking mechanism and a temperature sensing mechanism in a preferred embodiment of the present invention;

[0029] Figure 8 is a three-dimensional diagram of a valve body in a preferred embodiment of the present invention;

[0030] Fig. 9 is a front view of the toggle mechanism in a preferred embodiment of the present invention;

[0031] Fig.10 is a three-dimensional diagram of a second valve seat in a preferred embodiment of the present invention;

[0032] Fig.11 It is a three-dimensional diagram of a part of the fire-proof check valve in the preferred embodiment of the present invention (the valve plate and the connecting mechanism are omitted);

[0033] Fig.12 It is a three-dimensional diagram of a part of the fire-proof check valve in the preferred embodiment of the present invention (the toggle mechanism is omitted);

[0034] Fig.13 It is a three-dimensional diagram of the connecting mechanism in the preferred embodiment of the present invention. DETAILED DESCRIPTION

[0035] The technical solutions of the embodiments of the present invention are explained and described below in conjunction with the drawings of the embodiments of the present invention, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative work are all within the protection scope of the present invention.

[0036] See also Figure 2 and Figure 3 The fireproof check valve comprises a valve body 1 having an exhaust port 111, a valve plate 2 and a connecting mechanism 3. The valve body 1, the valve plate 2 and the connecting mechanism 3 are made of metal or other high temperature resistant materials. The connecting mechanism 3 is used to connect the valve plate 2 with the valve body 1 and can drive the valve plate 2 to close the exhaust port 111.

[0037] from Figure 3 It can be seen that the valve body 1 of this embodiment has an exhaust channel 11, and an exhaust port 111 is arranged on the exhaust channel 11. When the valve plate 2 closes the exhaust port 111, the exhaust channel 11 located on both sides of the exhaust port 111 will not be able to realize the flow of smoke, which means that when the valve plate 2 closes the exhaust port 111, the smoke in the user's room cannot pass through the fire check valve to enter the exhaust channel, and the smoke in the exhaust channel cannot pass through the fire check valve to enter the user's room. Of course, in the prior art, the valve body may include an annular baffle with an exhaust port, and there is no exhaust channel on this valve body.

[0038] There are three ways for the connection mechanism 3 on the fire check valve to close the exhaust port 111 through the valve plate 2: 1. Figure 3 As shown, the fire check valve includes a second elastic element 8, which is one of a second torsion spring, a tension spring and a compression spring. The second elastic element 8 is used to drive the connecting mechanism 3 to drive the valve plate 1 to move relative to the valve body 1 to maintain the tendency of the valve plate 1 to close the exhaust port 111; 2. The valve plate maintains the tendency to close the exhaust port under the action of its own gravity; 3. The connecting mechanism is eccentrically arranged to maintain the tendency of the valve plate to close the exhaust port.

[0039] See also Figure 1 , Figure 6 and Fig.11 , which is different from the prior art in that: in this embodiment, the fire check valve further includes a locking mechanism 4, a toggle mechanism 6, an elastic element and a temperature sensing mechanism 5. The present invention refers to the elastic element as a first elastic element 7 for easy distinction. The locking mechanism 4 and the toggle mechanism 6 are movably arranged on the valve body 1. The locking mechanism 4 has a locking position and an unlocking position, such as Figure 4As shown, when the locking mechanism 4 is in the locked position, the temperature sensing mechanism 5 is clamped between the locking mechanism 4 and the valve body 1. After the temperature sensing mechanism 5 is actuated, the first elastic element 7 drives the locking mechanism 4 to move from the locked position to the unlocked position through the toggle mechanism 6. Figure 5 As shown, when the locking mechanism 4 is located at the unlocking position, the valve plate 2 closes the exhaust port 111 .

[0040] In this embodiment, after the temperature sensing mechanism 5 is actuated, the toggle mechanism 6 drives the valve plate 2 to close the exhaust port 111 through the connecting mechanism 3. With such a design, the toggle mechanism 6 does not directly contact the valve plate 2 to prevent the valve plate 2 from being deformed by the impact of the toggle mechanism 6. Of course, in other embodiments of the present invention, after the temperature sensing mechanism is actuated, the toggle mechanism may also directly drive the valve plate to close the exhaust port.

[0041] See also Figure 8 The valve body 1 is provided with a guide channel for guiding the movement direction of the locking mechanism 4, at least part of the locking mechanism 4 is arranged in the guide channel, and when the locking mechanism 4 is in the locked position or the unlocked position, at least one end face of the locking mechanism 4 is located outside the guide channel. Such a design facilitates the removal of the locking mechanism 4 from the guide channel, and facilitates the arrangement of part of the temperature sensing mechanism 5 on the outside of the valve body 1 and the arrangement of the remaining part of the temperature sensing mechanism 5 on the inside of the valve body 1. In other embodiments of the present invention, the locking mechanism can be welded inside the valve body, and a space for clamping the temperature sensing mechanism is reserved between the locking mechanism and the side wall of the valve body.

[0042] Preferably, the valve body 1 includes a first exhaust pipe 101, a second exhaust pipe 103 and an annular baffle 102 that can abut against the valve plate 2. The first exhaust pipe 101 and the second exhaust pipe 103 are connected through the annular baffle 102. The annular baffle 102 encloses an exhaust port 111. The annular baffle 102 is provided with a guide hole 12, which is the guide channel. The locking mechanism 4 includes a locking rod, which passes through the guide hole 12. With such a design, the temperature sensing mechanism 5 can be arranged on the outside of the valve body 1 or on the inside of the valve body 1, which means that the fire check valve can achieve dual indoor and outdoor smoke isolation by setting a set of toggle mechanisms 6. In addition, in other embodiments of the present invention, the guide channel can also be set at other positions of the valve body by changing its shape. For example, a guide seat is provided on the inside of the valve body, and a guide groove is provided on the guide seat. The top of the guide groove is open, and two opposite openings are provided on the side wall of the guide groove. The guide groove is the guide channel; or the guide hole is provided on the mounting panel 104.

[0043] In this embodiment, when the temperature sensing mechanism 5 is clamped between the locking mechanism 4 and the valve body 1, part of the temperature sensing mechanism 5 is located on the outside of the valve body 1, and the remaining part of the temperature sensing mechanism 1 is located on the inside of the valve body 1. With such a design, the fire check valve can be used for both indoor and outdoor smoke isolation. Of course, in other embodiments of the present invention, when the temperature sensing mechanism is clamped between the locking mechanism and the valve body, the temperature sensing mechanism can be located only on the outside of the valve body; or, when the temperature sensing mechanism is clamped between the locking mechanism and the valve body, the temperature sensing mechanism can be located only on the inside of the valve body.

[0044] See also Figure 6 A fixing portion is provided at one end of the locking rod, and the temperature sensing mechanism 5 is clamped between the fixing portion and the annular baffle 102. Figure 7 It is not difficult to see that the locking rod includes a screw, the axial length of the screw rod 42 is greater than the sum of the lengths of the brazing ring 51 and the guide hole 12, the fixing portion is the head 41 of the screw, the temperature sensing mechanism 5 includes at least one brazing ring 51 sleeved on the locking rod, the brazing ring 51 has a mounting hole 511, and when the screw rod 42 passes through the mounting hole 511, the brazing ring 51 is clamped between the screw head 41 and the annular baffle 102. In other embodiments of the present invention, the locking mechanism includes a bolt and a nut, and the bolt passes through the brazing ring and the first metal plate and is fixedly connected to the nut.

[0045] Furthermore, in other embodiments of the present invention, the temperature sensing mechanism may include at least one solder plate, and the solder plate is clamped between the head of the screw and the annular baffle.

[0046] In this embodiment, a solder ring is clamped between the head 41 of the screw and the annular baffle 102, but in other embodiments of the present invention, the number of solder rings clamped between the fixing portion and the annular baffle can be adjusted according to actual needs.

[0047] See also Figure 6The temperature sensing mechanism 5 further includes a first metal plate 521, a second metal plate 523 and a brazing member 522 for connecting the first metal plate 521 and the second metal plate 523. The first metal plate 521 is detachably arranged at the other end of the locking rod, and a rotation stop 5231 is arranged on the second metal plate 523. When the locking mechanism 4 is located at the locking position, the rotation stop 5231 is engaged with the toggle mechanism 6 to prevent the first elastic element 7 from driving the toggle mechanism 6 to move relative to the valve body 1. In other embodiments of the present invention, the temperature sensing mechanism further includes a brazing rod, one end of the brazing rod is clamped between the locking rod and the valve body, and the other end of the brazing rod is provided with a rotation stop. When the locking mechanism is located at the locking position, the rotation stop is engaged with the toggle mechanism to prevent the first elastic element from driving the toggle mechanism to move relative to the valve body. The first metal plate 521, the second metal plate 523 and the brazing member 522 form a temperature sensing unit 52, and the temperature sensing unit 52 and the brazing ring 51 form a temperature sensing mechanism 5. When a fire occurs indoors, the brazing ring 51 melts, and the locking rod axially moves from the locked position to the unlocked position, so that the valve plate 2 closes the exhaust port 111. When a fire occurs outdoors, the brazing member 522 melts, and the first metal plate 521 separates from the second metal plate 523, so that the valve plate 2 closes the exhaust port 111.

[0048] See also Figure 7 , the height of the stopper 5231 is H1, the axial length of the brazing ring 51 is H3, and H1<H3. With such a design, after the brazing ring 51 melts, the axial movement range of the locking mechanism 4 relative to the valve body 1 is greater than H1, which means that when the locking mechanism 4 moves from the locked position to the unlocked position, the stopper 5231 will be separated from the toggle mechanism 6.

[0049] In this embodiment, the solder ring 51 and the solder piece 522 can be one or more solders selected from the group consisting of bismuth-based, indium-based, tin-based, cadmium-based, zinc-based and lead-based solders.

[0050] It is not difficult to conclude from the above description that the action of the temperature sensing mechanism 5 includes the melting action of the temperature sensing mechanism 5. In other embodiments of the present invention, the temperature sensing mechanism may include a memory metal, which is clamped between the locking mechanism and the valve body. After the memory metal is deformed (the deformation action includes but is not limited to the bending of the memory metal under pressure and the change of the thickness of the memory metal under pressure), the first elastic element drives the locking mechanism to move from the locked position to the unlocked position through the toggle mechanism. When the locking mechanism is in the unlocked position, the valve plate closes the exhaust port.

[0051] In this embodiment, the first metal plate 521 can be detachably set on the other end of the locking rod by means of snap-on, screw-on, hinged, etc. Preferably, a fixing section 5211 is provided on the first metal plate 521, and a threaded hole matching the rod portion 42 of the screw is provided on the fixing section 5211. Therefore, the rod portion 42 of the screw passes through the threaded hole to realize the fixed connection between the rod portion 42 of the screw and the first metal plate 521.

[0052] See also Figure 3 and Fig.13 The connecting mechanism 3 includes a connecting rod 31, the lower end of the connecting rod 31 is rotatably connected to the valve body 1, and the upper end of the connecting rod 31 is movably connected to the valve plate 2. In addition, in other embodiments of the present invention, the lower end of the connecting rod can slide along the slide rail on the valve body to enable the valve plate to close the exhaust port, while the upper end of the connecting rod is rotatably connected to the valve plate.

[0053] In this embodiment, the fireproof check valve also includes a bolt 91 and a nut 92. The bolt 91 passes through the connecting rod 31 and the valve plate 2 in sequence and is fixedly connected with the nut 92. When the bolt 91 passes through the connecting rod 31 and the valve plate 2 in sequence and is fixedly connected with the nut 92, the interval gap between the bolt head and the nut 92 is greater than the sum of the thickness of the valve plate 2 and the thickness of the bottom plate 301 on the connecting rod 31.

[0054] Preferably, the bolt 91 is a stepped bolt, which includes a bolt head, a stepped portion and a screw section in sequence along its axial direction, and the valve plate 2 is sleeved on the stepped portion.

[0055] In this embodiment, the connection mechanism 3 further comprises a rotating shaft 10, and the connecting rod 31 is rotatably connected to the second valve seat 107 via the rotating shaft 10. In other embodiments of the present invention, one of the connecting rod and the second valve seat is provided with a rotating shaft, and the other is provided with an axial hole matched with the rotating shaft.

[0056] See also Fig. 9 and Fig.11 The toggle mechanism 6 includes a toggle rod transversely arranged on the valve body 1, a transition portion is arranged at the edge of the toggle rod, and the middle position of the toggle rod protrudes outward. In other embodiments of the present invention, the toggle mechanism includes an arc plate, a rotating rod, and a fastener for connecting the arc plate and the rotating rod.

[0057] See also Fig. 9 , the lever is provided with a receiving cavity for limiting the installation position of the temperature sensing element 5, specifically: a positioning groove 611 is provided on the outer wall of the lever, the positioning groove 611 is the receiving cavity, and when the anti-rotation portion 5231 is engaged with the lever, the second metal plate 523 is located in the positioning groove 611. Such a design effectively limits the position where the second metal plate 523 is engaged with the toggle mechanism 6. In other embodiments of the present invention, the lever is provided with a positioning hole, the positioning hole is the receiving cavity, and the second metal plate can be inserted into the positioning hole.

[0058] Preferably, the depth of the positioning groove 611 is H2, where H2>the thickness of the second metal plate 523.

[0059] from Fig. 9 It can be seen that the middle position of the lever is provided with an arc segment 61 for connecting the adapter, and the outer side wall of the arc segment is arc-shaped. Such a design can prevent the lever from interfering with the valve body 1 during movement.

[0060] In this embodiment, the adapter includes a rotating shaft section 62 and a clamping section 63, and the first elastic element 7 is a first torsion spring, which is sleeved on the clamping section 63. Of course, in other embodiments of the present invention, the adapter may include only a rotating shaft section, and the first torsion spring is sleeved on the rotating shaft section; or, the adapter may include only a shaft hole section, and the first torsion spring is sleeved on the valve body.

[0061] See also Fig.12 and Fig.13 The connecting rod 31 includes a first side plate 302, a second side plate 303 and a bottom plate 301 for connecting the first side plate 302 and the second side plate 303. The first side plate 302, the bottom plate 301 and the second side plate 303 form a receiving cavity 311. The first side plate 302 is provided with a first inclined section 3021, and the second side plate 303 is provided with a second inclined section 3031. After the temperature sensing mechanism 5 is actuated, the toggle mechanism 6 slides forward along the first inclined section 3021 and / or the second inclined section 3031, so that the connecting rod 31 closes the exhaust port 111 through the valve plate 2. With such a design, the movement direction of the toggle mechanism 6 is limited.

[0062] In this embodiment, at least one protrusion for preventing the lever from sliding in the reverse direction thereof is provided on the first inclined section 3021 and / or the second inclined section 3031. Such a design effectively prevents the valve plate 2 from opening the exhaust port 111 under the action of the high-temperature airflow.

[0063] Preferably, the protrusion is an inverted tooth, and with such a design, the lever cannot slide in the reverse direction. In other embodiments of the present invention, the protrusion may be a boss.

[0064] See also Figure 3 and Fig.10 The valve body 1 is provided with a first valve seat 106 and a second valve seat 107, the first valve seat 106 is connected to the valve body 1 by a first fixing screw 20, and the second valve seat 107 is connected to the valve body 1 by a second fixing screw 30. In other embodiments of the present invention, the first valve seat is snap-connected to the valve body, and the second valve seat is connected to the valve body by welding.

[0065] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. A fire check valve, comprising a valve body with an exhaust port, a valve plate and a connecting mechanism, wherein the connecting mechanism is used to connect the valve plate with the valve body and can drive the valve plate to close the exhaust port, characterized in that: The fire-proof check valve further comprises a locking mechanism, a toggle mechanism, an elastic element and a temperature sensing mechanism. The locking mechanism and the toggle mechanism are arranged on the valve body. The locking mechanism has a locking position and an unlocking position. When the locking mechanism is located at the locking position, the temperature sensing mechanism is clamped between the locking mechanism and the valve body. After the temperature sensing mechanism is actuated, the elastic element drives the locking mechanism to move from the locking position to the unlocking position through the toggle mechanism. When the locking mechanism is located at the unlocking position, the valve plate closes the exhaust port. The valve plate is made of metal; When the temperature sensing mechanism is clamped between the locking mechanism and the valve body, the temperature sensing mechanism is located on the outside of the valve body; or, the temperature sensing mechanism is located on the inside of the valve body; or, part of the temperature sensing mechanism is located on the outside of the valve body, and the remaining part of the temperature sensing mechanism is located on the inside of the valve body; After the temperature sensing mechanism is actuated, the toggle mechanism drives the valve plate to close the exhaust port through the connecting mechanism; or, after the temperature sensing mechanism is actuated, the toggle mechanism drives the valve plate to close the exhaust port.

2. The fire check valve according to claim 1, characterized in that: The locking mechanism moves axially relative to the valve body so as to move the locking mechanism from a locking position to an unlocking position.

3. The fire check valve according to claim 1, characterized in that: The valve body is provided with a guide channel, and at least part of the locking mechanism is arranged in the guide channel. When the locking mechanism is located at a locking position or an unlocking position, at least one end surface of the locking mechanism is located outside the guide channel.

4. The fire-proof check valve according to claim 3, characterized in that: The valve body comprises an annular baffle plate, a guide hole is arranged on the annular baffle plate, the guide hole is the guide channel, and the locking mechanism comprises a locking rod, and the locking rod passes through the guide hole.

5. The fire-proof check valve according to claim 4, characterized in that: A fixing portion is provided at one end of the locking rod, and the temperature sensing mechanism is clamped between the fixing portion and the annular baffle.

6. The fire check valve according to claim 5, characterized in that: The temperature sensing mechanism comprises at least one solder ring sleeved on the locking rod, and the at least one solder ring is clamped between the fixing portion and the annular baffle.

7. The fire check valve according to claim 6, characterized in that: The temperature sensing mechanism also includes a first metal plate, a second metal plate and a solder piece for connecting the first metal plate and the second metal plate. The first metal plate is detachably arranged on the other end of the locking rod. The second metal plate is provided with a rotation stop. When the locking mechanism is in the locking position, the rotation stop is engaged with the toggle mechanism to prevent the elastic element from driving the toggle mechanism to move relative to the valve body.

8. The fire check valve according to claim 7, characterized in that: The height of the anti-rotation portion is less than the axial length of the solder ring; the locking rod comprises a screw, the fixing portion is the head of the screw, and the rod of the screw is fixedly connected to the first metal plate.

9. The fire check valve according to claim 4, characterized in that: The temperature sensing mechanism also includes a solder rod, one end of which is clamped between the locking rod and the valve body, and the other end of the solder rod is provided with a stopper. When the locking mechanism is in the locking position, the stopper is engaged with the toggle mechanism to prevent the elastic element from driving the toggle mechanism to move relative to the valve body.

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